The ESA (Section 3) defines "endangered species" as "any species which is in danger of extinction throughout all or a significant portion of its range." "Threatened species" is defined as "any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range." NMFS considers a variety of information in evaluating the level of risk faced by a DPS, including: 1) absolute numbers of fish and their spatial and temporal distributions, 2) current abundance in relation to historical abundance and carrying capacity of the habitat, 3) trends in abundance, based on indices such catch statistics, catch per unit effort (CPUE), and spawner-recruit ratios, 4) natural and human-influenced factors that cause variability in survival and abundance, 5) possible threats to genetic integrity (e.g., selective fisheries and interactions between cultured and natural populations), and 6) recent events (e.g., climate change and changes in management) that have predictable short-term consequences for the abundance of a DPS. Additional risk factors, such as disease prevalence or changes in life-history traits, also may be considered in the evaluation of risk to a population.
The determination of whether a species is threatened or endangered, according to the ESA, should be based on the best scientific information available, after taking into consideration conservation measures that are proposed or in place. The BRT did not evaluate likely or possible effects of conservation measures. Therefore, they did not make recommendations on whether DPSs should be listed as threatened or endangered species, because that determination requires evaluation of factors not considered by the BRT. However, the BRT did draw scientific conclusions about the risk of extinction faced by DPSs under the assumption that present conditions will continue, recognizing that natural demographical and environmental variability is an inherent feature of present conditions. Conservation measures will be taken into account by the NMFS Northwest Regional Office in making listing recommendations. The following sections summarize the kinds of information the BRT considered in evaluating the potential effects of risk factors on the each of the DPSs identified by the BRT.
The absolute number of individuals in a population is important in assessing two aspects of extinction risk. First, population sizes of small populations can be an indicator of whether the population can sustain itself in the face of environmental fluctuations and small-population stochasticity, even if the population currently is stable or increasing. This conclusion follows from the theory of minimum viable populations (MVP) (Gilpin and Soulé 1986, Thompson 1991). Second, present abundance in a declining population is an indicator of the time expected until the population reaches critically low numbers. This follows from the idea of "driven extinction" (Caughley and Sinclair 1994). In addition to absolute numbers, the spatial and temporal distributions of adults are important in assessing risk to a DPS. Spatial distribution is important, both at the scale of the spawning population and the metapopulation.
Assessments of marine fish populations have focused on determining abundance and trends from models fit to catch, survey and biological data. Catch records, fishery and survey CPUE, and biomass estimates from research cruises constitute most of the data available to estimate abundance. The estimated numbers of reproductive adults is the most important measure of abundance in assessing the status of a population. Data on other life-history stages can be used as a supplemental indicator of abundance.
The relationship of present abundance to present carrying capacity is important for evaluating the health of a population, but a population with abundance near the carrying capacity of the habitat it occupies does not necessarily indicate that the population is healthy. Population abundances near carrying capacity imply that the effectiveness of short-term management actions is limited in increasing population abundance. The relationship between current abundance and habitat capacity to the historical relationship between these variables is an important consideration in evaluating risk. An understanding of historical conditions provides a perspective of the conditions under which present populations evolved. Estimates of historical abundances also provide the basis for establishing long-term abundance trends. Comparisons of past and present habitat capacity can also indicate long-term population trends and potential problems stemming from population fragmentation.
Short- and long-term trends in abundance are primary indicators of risk in natural populations. Trends may be calculated with a variety of quantitative data, including catch, CPUE, and survey data. Trend analyses for the three species considered in this status review are greatly limited by the lack of long time series of abundances in greater Puget Sound. The time series of abundance estimates that are available are limited in their usefulness by the lack of regular sampling, by use of different survey methods for a species, and, for harvest data, by the imposition of harvest regulations. The influence of environmental variability on population abundances also limits the use of short-term trends, because the climate changes in the late-1970s and 1980s coincided with apparent declines in population abundances for each of the three species being considered in this document.
Several natural and anthropogenic factors influence the degrees of risk facing populations of marine fish in greater Puget Sound. Recent changes in these factors may influence the degree of risk of a population without apparent changes in abundance, because of time lags between the events and the effects on the population. Thus, a consideration of these effects extends beyond the examination of recent trends in abundance. The BRT considered documented physical and climatic changes, but did not consider possible effects of recent or proposed conservation measures. Population variability in itself may not be an indication of risk. Habitat degradation and harvest have most likely weakened the resilience of populations in greater Puget Sound to climate variability. These effects are not easily quantified and are dealt with in more specific detail in the following section.
Artificial propagation and enhancement of populations in greater Puget Sound does not presently appear to be a risk factor for the species considered here. However, mariculture of some species is under development, and the effects of hatchery releases on natural populations may be important in the future. The interbreeding of cultured and natural fish can potentially lead to a loss in fitness of naturally-spawning populations. The genetic effects of artificially-propagated releases of species with high fecundities, as is common for many marine fishes, could be substantial. Ryman and Laikre (1991), Waples and Do (1994), and Ryman et al. (1995) discussed possible risks associated with enhancement of marine populations, but these risks are difficult to quantify and to incorporate into risk analysis. The chief concern is that the release of propagated fish, which may be inadvertently modified by breeding practices and novel-rearing environments, may lead to the erosion of genetic diversity and fitness in natural populations.
Human activities, other than population enhancement, can also influence the genetic characteristics of natural populations. These include size-selective harvest methods (Nelson and Soulé 1987); introductions of non-native species; and alterations of marine habitats by shoreline development, increased siltation in river runoff, and pollution. At the present time, empirical information documenting the genetic effects of these kinds of changes is largely lacking.
Coupled changes in atmospheric and ocean conditions have occurred on several different time scales and have influenced the geographical distributions, and hence local abundances, of marine fishes. On time scales of hundreds of millennia, periodic cooling produced several glaciations in the Pleistocene Epoch (Imbrie et al. 1984, Bond et al. 1993). The central part of greater Puget Sound was covered with ice about 1 km thick during the last glacial maximum about 14,000 years ago (Thorson 1980). Since the end of this major period of cooling, several population oscillations of pelagic fishes, such as anchovies and sardines, have been noted on the West Coast of North America (Baumgartner et al. 1992). These oscillations, with periods of about 100 years, have presumably occurred in response to climatic variability. On decadal time scales, climatic variability in the North Pacific and North Atlantic Oceans has influenced the abundances and distributions of widespread species, including several species of Pacific salmon (Francis et al. 1998, Mantua et al. 1997) in the North Pacific, and Atlantic herring (Alheit and Hagen 1997) and Atlantic cod (Swain 1999) in the North Atlantic. Recent declines in marine fish populations in greater Puget Sound may reflect recent climatic shifts (Fig. 8). However, we do not know whether these climatic shifts represent long-term changes or short-term fluctuations that may reverse in the near future. Although recent climatic conditions appear to be within the range of historical conditions, the risks associated with climatic changes may be exacerbated by human activities (Lawson 1993).
One of the greatest difficulties in the status review process is organizing a large amount of information regarding the biology of the species, genetics, and population trends over time. Often, the ability to measure or document risk factors is limited, and information is not quantitative and is very often lacking altogether. In assessing risk, it is often important to include both qualitative and quantitative information, and the method by which a BRT can do so takes several forms. In the next section, information to assist in assessing risk is presented in the format of the types of methods used in the BRT deliberations. The first is a presentation of information discussed in West (1997). This is a quantitative discussion that presents and references important pieces of information, but does not attempt to make a quantitative assessment of these factors. The second method for assessing risk is that of Wainwright and Kope (1999). This method was used in the Pacific salmon BRT process and provides a method to organize and summarize the professional judgement of a panel of knowledgeable scientists. This is a risk matrix approach and includes information on abundance, population trends, productivity and variability, genetic integrity and habitat condition/capacity. Another approach recently put forth by Musick et al. (2000), provides criteria by which to define risk. These criteria are based on productivity measures such as intrinsic rates of increase, age at maturity and maximum age. This provides another method to examine and organize available information for the evaluation of risk and an opportunity to compare the results of the methods. In addition, the stock assessment specialists, serving on the rockfish BRT, consider that it is important to set these analyses and results in context with the Sustainable Fisheries Act and the analyses that are made with respect to overfished stocks.
A useful method of assessing the risk of extinction for Pacific salmon species has been developed by Wainwright and Kope (1999) as described previously. This method was adapted for use by the rockfish BRT in their review of these species to evaluate the risk of extinction for each of the three rockfish species. The primary risk considerations to be considered in this evaluation are abundance of the rockfish species, the amount and quality of preferred habitats, and trends in rockfish populations and habitats. An analysis of loss of genetic integrity will be deleted due to the absence of supplementation programs for these fish.
In addition, Musick et al. 2000 presents criteria to define risk and decline thresholds for marine fish to determine whether a DPS is at risk. These criteria are similar to those examined in Wainwright and Kope (1999), however, they are organized somewhat differently. The criteria are rarity, small range and endemics, specialized-habitat requirements and population decline. Decline thresholds are based on population resilience of the species.
The risks to the survival of the demersal rockfish, copper (Sebastes caurinus), quillback (S. maliger) and brown (S. auriculatus), identified in this section are listed by West (1997) as "anthropogenic stressors and natural limiting factors", and include overharvesting, loss or degradation of habitat, predation by pinnipeds and fish, and pollution-related adverse effects. Each of these risk factors will be described below. Because the rockfish BRT determined that each rockfish species has at least one distinct population segment (DPS) consisting of Puget Sound proper, the emphasis of the evaluation of risk evaluation will be on risks inherent to Puget Sound proper. Other geographical areas will also be discussed, but primarily in relation to Puget Sound proper.
Brown, copper, and quillback are some of the most commonly caught rockfish species in greater Puget Sound. Catch rates of commonly caught rockfish species by recreational fishers in North Puget Sound declined from 1.8 fish/trip in 1977 to 1.0 fish/trip in 1981. Subsequent to this decline, the catch rates varied between 0.56 and 1.07 through 1999 (W. A. Palsson7) (Fig. 4). Similarly, catch rates of rockfish in South Sound dropped from 1.01 fish/trip in 1977 to 0.41 fish/trip in 1983 and remained at approximately 0.50 fish/trip until 1994. After 1994, the catch rates leveled off to between 0.27 and 0.30 fish/trip (W. A. Palsson8) (Fig. 4). These catch rates were influenced by increasingly restrictive fishery regulations, so are not necessarily proportional to population abundance. In 1994, the bag limit was reduced from 10 to 5 rockfish in North Puget Sound and from 5 to 3 rockfish in Puget Sound proper. The reduction did not appear to have an impact in North Puget Sound, but there may have been a delayed impact in Puget Sound proper because the catch rate dropped in 1995 and then was stable.
Palsson (W. A. Palsson, see Footnote 8) estimated species composition of some of these recreational catches from 1980 to 1999. In North Puget Sound the relative composition of copper and quillback remained somewhat similar between 1980 and 1989, but by 1996, there were relatively more copper rockfish (44 to 64.5%) caught than quillback rockfish (17.9 to 38%) (Fig. 21). A very similar trend was observed in Puget Sound proper (Fig. 22). The percentages of brown rockfish in Puget Sound proper were generally in decline through the 1980s and mid-1990s, but they increased in the late-1990s (Fig. 22).
Investigations of no-take marine refuges in North Puget Sound and Puget Sound proper provided indirect evidence that these rockfish populations were declining because of harvesting. From 1992 to 1997, Palsson and Pacunski (1995), and Palsson (1998) compared populations of the three rockfish species at the Edmonds Underwater Park (EUP, created in 1970), San Juan Marine Preserves (Shady Cove, created in 1990), and fishing sites in Puget Sound proper and North Puget Sound. Population densities for all copper rockfish were at least eight times higher at EUP, whereas Shady Cove was about two times higher than at fished sites (Table 3). The number of copper rockfish >40 cm found at EUP was 26 times that found at the fishing sites. The numbers at the no-take and fishing sites were about the same for the San Juan Islands (Table 3).
For quillback rockfish, the results were not as dramatic. More quillback were found at the EUP (17.3 fish/transect) and a fished site (Boeing Creek, 35.8 fish/transect), compared to the other fished sites (0-2.1 fish/transect). Very few quillback were counted at the San Juan sites. A different result was obtained for quillback rockfish >40 cm; fish of this size were essentially found only at the EUP.
The EUP was of no apparent benefit to brown rockfish. A variety of factors may have accounted for this result. They tend to be more generalists with regard to habitat preferences, and Palsson, (W. A. Palsson, see Footnote 8) suggests that brown rockfish are readily displaced by copper rockfish. Thus, copper rockfish may be excluding brown rockfish from the EUP.
Analysts have not had sufficient data to use standard stock assessment models such as Stock Synthesis (Methot 2000) or AD Model Builder (Fournier 2000) to evaluate impacts of harvest on rockfish in greater Puget Sound. However, declines in overall abundance and relatively high densities of rockfish at unfished sites indicate that harvesting has impacted population size. However, if the relative abundance of large copper and quillback rockfish in the EUP to fished sites in Central Puget Sound proper are indicative of the overall reduction of spawning output in greater Puget Sound from the unfished state, use of the Pacific Fishery Management Council criteria for overfishing for rockfish in coastal waters would result in classification of the two species as overfished (<25% of unfished spawning output).
Yamanaka and Kronlund (1997) reported that fishery independent surveys in statistical area 12 in the north end of the Strait of Georgia showed declines in survey catch-per-unit-effort (CPUE) of fully recruited quillback rockfish (>11 yr) and overall declines in the mean age of quillback rockfish. Declines in mean age were also apparent in commercial fishery samples (Yamanaka and Kronlund 1997). Stock assessments of copper and quillback rockfish in the Strait of Georgia in 1998 were performed by Kronlund et al. (1999). They used two primary populations near the Campbell River (north end of the Strait) and the Gulf Islands (south end of the Strait). Trends in CPUE by hand line gear in the two areas were similar between 1986 and 1996. However, CPUE values in the Gulf Island area tended to be lower than those from near Campbell River by 1996 (Fig. 23). Trends for quillback rockfish alone were very similar (Fig. 24).
Richards and Cass (1987) reported decreases in the size of rockfish stocks in the Strait of Georgia (primarily copper and quillback rockfish). They discounted lack of recruitment because "rockfish are long-lived and recruit to the fishery over several years. They stated that "the most likely explanation for this decrease is overfishing".
Early life-history stages of rockfish are dependent upon on eelgrass, kelp and other macrophytes as sources of food and for protection from predators (Love et al.1991). Kelp is important to juveniles and adults. No region-wide quantitative trend analysis for eelgrass coverage have been reported for greater Puget Sound. Levings and Thom (1994) suggest an increase of 53% in kelp beds. Sewell (1999) of the Puget Sound Water Quality Action Team (PSWQAT) studied areas of floating kelp beds in the Strait of Juan de Fuca and Washington coast, and overall there were no significant changes between 1989 and 1997. However, the kelp bed on the north side of Protection Island disappeared during that period.
The Washington State Department of Natural Resources conducted a study in 1995 to estimate the extent of shoreline modification in greater Puget Sound (PSWQAT 2000). Types of modifications included bulkheading, filling, dredging, aquaculture, and dock construction and other water-based settlement. The most extensive intertidal modification was found in the Main Basin, where 45% was modified. Hood Canal and the Whidbey Basin had similar levels of intertidal modification (24%), and North Puget Sound had the least (11%). Kelp beds are commonly considered to be important habitat for young-of-the-year (YOY) of most rockfish species. Macrocystis is not present in Puget Sound proper, whereas Nereocystis (bull kelp) is distributed with varying densities throughout Puget Sound proper (Sewell 1999; T. F. Mumford, Jr. 9). For example, Bailey et al. (1998) reported Nereocystis on only 3% of the shoreline in the Main Basin of Puget Sound proper (primarily in the northern part, primarily eastern shore), compared to17.5% of the shoreline in North Puget Sound. Kelp and other high profile algae are virtually absent in Puget Sound proper during the winter - the most common types of vegetation present during the winter are red algae, such as Antithamnion sp. (Shaffer 1998, Neushul 1967) and Sargassum muticum (Maxell and Miller 1996). This latter species was introduced to greater Puget Sound during the 1940s from Japan (Abbott and Hollenberg 1976).
In an article describing the results of a study of the use of a variety of habitat types by YOY rockfish, Doty et al. (1995) stated "Very few YOY rockfish were observed in shallow water habitats between December and July". They also reported that Nereocystis is the preferred habitat (Figs. 25, 26) when it is present. However, based on studies conducted in British Columbia, Haldorson and Richards (1986) suggest that eelgrass habitat is preferred by YOY rockfish (Fig. 27). The reason for the differing results is not known, but the latitudinal difference between British Columbia and greater Puget Sound may be one factor.
Older juvenile and adult copper and quillback rockfish prefer high-relief, broken rock habitats (Richards 1987). Limited amounts of these types of habitat are present in the main stem of Puget Sound proper. Between 1993 and 1995, Pacunski and Palsson (1998) estimated 207 km2 of rocky-reef habitat in North Puget Sound, and only 9.9 km2 in the Main Basin and south Puget Sound. Adult brown rockfish are found on a variety of habitat types, including high- and low-relief areas and sandy bottoms, but are generally not found on artificial reefs (Matthews 1990a).
Everitt et al. (1981) reported minor consumption of rockfish by pinnipeds in greater Puget Sound. Analyses of harbor seal scat from the Strait of Juan de Fuca showed that rockfish otoliths were in 4% of the samples. Only 0.3% of the harbor seal scat samples from Gertrude Island had rockfish otoliths. Rockfish otoliths were not detected in scat from California sea lions from Port Gardner.
Wiens and Scott (1975) reported that rockfish were an important prey item for the Oregon Coastal Common Murre (Uria aalge), consuming equal quantities of anchovy, smelt, cod, and rockfish over the year. However, according to Mahaffy et al. (1994), the population of Common Murre in the Georgia Basin is quite small.
Juvenile rockfish are the primary prey item for lingcod, followed by benthic gastropods, siphonophores, ascidians, and polychaetes (Matthews 1987). Pacific Ocean chinook and coho salmon have 7% and 14% (percent biomass), respectively, of rockfish as prey items in their stomachs (Fresh et al. 1981). Fish were a major item in greater Puget Sound chinook, but herring were the major prey species, with other fish only 6% of the biomass.
A variety of chemical contaminants are found within the main basin of Puget Sound proper below Admiralty Inlet, the area occupied by the Puget Sound proper quillback, copper, and brown rockfish DPSs. Contaminants identified in sediments and water which may be toxic to fish include a number of heavy metals; chlorinated pesticides, such as DDTs, chlordanes, and, dieldrin; dioxins and furans; PCBs; and aromatic hydrocarbons (AHs). Concentrations of these substances in sediments are monitored regularly as part of the Puget Sound Ambient Monitoring Program (PSAMP), run by the Puget Sound Water Quality Action Team, and have also been measured in other surveys by Federal agencies such as NOAA and EPA. Currently, over 15,000 acres of intertidal and subtidal lands have been surveyed in urban embayments of greater Puget Sound as part of the PSAMP (PSWQAT 2000). About 38% of this area has been identified as contaminated above state standards, so the problem is not negligible. Most contaminated sediments are located in industrialized areas of the Sound, such as Elliott Bay, Commencement Bay, Sinclair Inlet, and Everett Harbor. Some contaminants of concern (PCBs, DDTs) are no longer being released into the environment, and levels are gradually declining, but high-residual concentrations are still found in many industrialized areas. Others, such as PAHs, are still being released, especially through non-point sources, and do not appear to have declined greatly over the last 20 years.
Demersal rockfish have several traits that may predispose them to accumulation of contaminants. They are carnivorous, so they feed on organisms that may have taken up and bioaccumulated contaminants, and they are very long-lived, non-migratory, and reside close to sediments, so their potential for long-term exposure is high (West 1997). In fact, a few studies have been conducted that confirm that certain chemical contaminants (e.g., PCBs, PAHs, and mercury) are taken up by quillback rockfish in urban areas of Puget Sound proper (Malins et al. 1982, PSWQAT 2000; West et al. 1998; G. Ylitalo10, and J. West (see Footnote 6). The earliest of these (Malins et. al. 1982), measured liver concentrations of PCBs and DDTs in quillback rockfish from four sites in Elliott Bay. Concentrations of PCBs and mercury have also been measured in rockfish muscle as part of the PSAMP since 1995. More recently, additional analyses have been conducted to measure specific dioxin-like PCB congeners in muscle tissue, and to evaluate rockfish exposure to PAHs. Because PAHs are metabolized by fish and do not accumulate in tissues, PAH exposure is assessed by measuring concentrations of metabolites in bile. Results of these studies are presented in Tables 4-9.
All studies show accumulation of PCBs in rockfish from urban sites or near-urban sites in Puget Sound proper (Elliott Bay, Sinclair Inlet, Blakely Rocks). However, the data from the three studies are not strictly comparable. Concentrations vary widely from study to study due to the year when fish were collected, the sites where fish were sampled, and the tissue analyzed, and differences in methodology. There is also some uncertainty associated with estimates of whole-body contaminant concentrations based on concentrations in liver or muscle. Still, the data suggest that PCB concentrations have declined in rockfish since the mid-1970s. Current PCB concentrations in muscle range from about 50-500 ng/g wet wt in rockfish from urban sites, depending on the methodology used. Particularly high concentrations of PCBs were found in older male rockfish (West et al. 1998). Concentrations were lower in adult females, probably because the compounds were transferred to the lipid-rich yolk of their eggs during reproduction, where they could be taken up by developing larvae.
The level of PCB exposure that would be likely to cause health effects in rockfish has not been established. However, the estimated body residue effect threshold for salmonids, based on a range of field and laboratory studies, is 24_72 ng/g wet wt, assuming a 1_3% wet weight whole body lipid content (Meador, unpubl. data). These lipid levels approximate those in rockfish. In recent studies, lipid concentrations in muscle tissue of quillback rockfish sampled from greater Puget Sound ranged from 0.02_2.8% wet weight, with the majority of samples below 1% (West et al. 1998, G. Ylitalo (see Footnote 10). If the salmon PCB threshold is applied to greater Puget Sound rockfish, the data suggest that, even using the most conservative estimates of tissue PCB concentration, rockfish from all-urban to near_urban sites could be at some risk for biological injury due to PCB contamination. The effects associated with exposure at these levels are generally sublethal, and range from biochemical alterations, such as toxicant metabolizing enzyme induction, to effects on growth, reproductive function, and disease resistance (Meador, unpubl. data).
Concentrations of PCBs have also been measured in a limited number of copper and brown rockfish from a few sites in Puget Sound proper (See Tables 4-6). Trends are similar to those in quillback rockfish, but data are too limited to draw any conclusions about the risk to these species of chemical contaminants.
Mercury is another contaminant that is of particular concern in quillback rockfish. Some mercury accumulation was found in muscle tissue of rockfish from all areas sampled in greater Puget Sound as part of the PSAMP (West et al. 1998, PSWQAT 2000). Average concentrations range from 0.22-0.84 mg/kg in muscle tissue, with highest concentrations in fish from Sinclair Inlet. As with PCBs, mercury concentrations were highest in older fish, but in this case the relationship held for both males and females. Mercury concentrations comparable to those in the more highly exposed rockfish (0.5-1.5 mg/kg) are have been associated with impaired reproduction, reduced larval growth and survival, teratogenic effects in other species (rainbow trout, fathead minnow) (Beckvar et al. 1996), so could be a threat to rockfish productivity. Moreover, concentrations in some of the most contaminated fish equaled or exceeded the FDA human consumption guideline of 1 mg/kg.
Rockfish from urban sites (e.g., Elliott Bay) also show exposure to both high and low molecular weight PAHs. Exposure, based on bile metabolite levels, is somewhat lower than for bottomfish species (i.e., English sole) from the same sites, possibly because of differences in habitat and diet (PSWQAT 2000). Highest-exposure levels approximate those where liver disease, growth and reproductive impairment begin to occur in English sole (Johnson, unpubl. data).
Although exposure to chemical contaminants in quillback rockfish from greater Puget Sound has been clearly documented, information on the biological effects of exposure is very limited. Studies conducted in late-1970s (Malins et al. 1982) showed that rockfish from urban areas (Elliott Bay, Commencement Bay) exhibited some degenerative conditions in liver and kidney, and proliferative conditions in gills (Table 9). However, they did not develop liver cancer and related lesions that are characteristic of some species of Puget Sound proper flatfish residing in the same areas (Malins et al. 1982, see M. S. Myers et al. 1998 for a more recent review on toxicopathic disease in Puget Sound proper bottomfish). Whether this is primarily due to lower levels of exposure in the rockfish, or to lower sensitivity to the effects of some of these toxicants is not known.
Some preliminary data on larval abnormalities in quillback rockfish from Elliott Bay and Sinclair Inlet have been collected in association with the PSAMP program (Carla Stehr12; J. West, see Footnote 6.) Results indicate that larvae of fish from these sites show a certain low level of abnormalities, but there is too little information to be certain that these levels are clearly different from background level in reference fish.
Studies conducted by the WDFW (West and O'Neill 1995) indicate that growth rates are reduced in rockfish from Puget Sound proper in comparison to rockfish from San Juan Island (North Puget Sound). It is possible that exposure to chemical contaminants could contribute to some of these growth alterations, because some of the contaminants to which rockfish are exposed (PCBs, PAHs) have been shown to suppress growth rates of other fish (Casillas et al. 1993, Casillas et al. 1995, Rice et al. 2000, Gutjahr-Gobell et al. 1999). However, the linkage has not been demonstrated, and other factors (e.g., genetics, fishing pressure, food supply) could be influencing rockfish growth rates to a greater extent than exposure to contaminants.
In summary, the available data indicate that quillback rockfish residing at urban and near-urban sites that are part of the Puget Sound proper DPS are exposed to PCBs, PAHs, and mercury at concentrations that could potentially lead to sublethal health effects that could reduce the productivity of these fish. Less data are available on contaminant exposure in copper or brown rockfish, although their exposure levels are likely to be similar to those observed in quillback rockfish from the same sites. However, almost no studies have been conducted to confirm the effects of these contaminants on any of the three rockfish species proposed for listing in greater Puget Sound. Moreover, it is not clear what proportion of the total rockfish population is made up of fish from contaminated sites. In the absence of this information, it is difficult to evaluate the seriousness of the risk posed to rockfish by chemical contaminants, although the evidence suggests that they may contribute to the decline of rockfish populations in greater Puget Sound.
According to Terrie Klinger13, out of more than 6,500 releases of drift cards in the San Juans, and more than 2,600 recoveries, 8 were recovered south of Admiralty Inlet. Of these 8, 7 were recovered just south of Admiralty Inlet, and 1 was recovered a year later south of Seattle near Des Moines. Klinger's interpretation is that virtually nothing enters the main basin of Puget Sound proper from the San Juan Islands or Eastern Basin of the Strait of Juan de Fuca on the surface. Thus, it is not likely that North Puget Sound is a significant source of surface-associated pelagic early life-history stages of rockfish to Puget Sound proper. However, general circulation studies identify some mixing of subsurface waters, so limited exchange is possible.
West's (1997) presentation of risk factors for copper, quillback and brown rockfish in greater Puget Sound points to overharvest as the probable major factor contributing to the decline of these fish. However, because no standard stock assessment has been completed on these species, it is difficult to evaluate the information provided by WDFW. Other factors that may be important are loss or degradation of nearshore nursery habitats, however, no recent, comprehensive Puget-Sound-wide information on this exists, so what remains is isolated reports by researchers regarding habitat loss. The increase in abundance of California sea lions and harbor seals may also play a role in the decline of these species, and new studies of diet for these species may shed additional light on this. Increased predation on larval and juvenile demersal fish by delayed-release Pacific salmon may also be important. However, little is known about the pelagic phase of these species, so it is difficult to predict what effect these salmon might have. Disease or loss of fitness due to accumulation of contaminants in adult rockfish may be important, and loss of fitness due to exposure of larvae and juveniles to contaminants cannot be ruled out. However, some of the contaminant loads in these fish seem to be lessening, and there is no clear-cut evidence as to the effects of these contaminants on these species of rockfish.
Copper rockfish have been relatively abundant in Puget Sound proper (Bargmann 1977). Three primary methods are used to assess the abundance of rockfish in Puget Sound proper and San Juan Islands (North Puget Sound). One method involves a video-acoustic technique (VAT) (Table 10) using a remotely-controlled video camera mounted on a platform to survey habitat and associated fish species on potential reef habitats (Pacunski and Palsson 1998). The videos were later viewed in a quantitative manner and estimates of population density were calculated. Another method involves underwater surveys by SCUBA divers of reef habitat (Table 11). The third method uses standard bottom trawl techniques to estimate populations based on catch data and surface area trawled. The underwater visualization methods estimate rockfish populations on rocky reefs, which is their preferred habitat; whereas, trawls sample low-profile habitats that are generally not preferred by copper rockfish.
Pacunski and Palsson (1998) and Palsson (W. A. Palsson, see Footnote 8) reported on VAT surveys conducted between 1993 and 1996. Although these data are several years old, they do give some indication about the relative abundance of the three rockfish populations in near-shore reef habitats (0 to 38 m) in North Puget Sound and Puget Sound proper. The population of copper rockfish in Puget Sound proper are estimated to be approximately 450,000 fish in 1995-1996 (Table 10). The data in Table 10 indicate that copper rockfish in Puget Sound proper are somewhat more abundant and more evenly distributed than quillback rockfish.
While Palsson (W. A. Palsson14) noted that copper rockfish were not found at numerous VAT sites in areas with apparently suitable habitat in Puget Sound proper, they were found at numerous areas with sites having similar habitat (Fig. 28). With exception of the southern most part of Puget Sound proper, copper rockfish were found in areas of the Sound with predominantly rocky-reef habitat, although copper rockfish were not found in some of the individual sites containing apparently suitable habitat within these areas (Figs. 28, 29). The length-frequency characteristics of recreationally-caught copper rockfish from Puget Sound proper remained relatively constant between 1975 and 1999 (W. A. Palsson, see Footnote 8). The average length during this period was approximately 34 cm.Palsson (W. A. Palsson, see Footnote 8) investigated egg production in copper rockfish using data obtained from the surveys of recreational catches in North Puget Sound and Puget Sound proper (see Fig. 30 for the catch data). Egg production was estimated by calculations based on fish length and historical data on fecundity and egg production. Relative egg production (percent of production relative to the peak year for the respective geographical area) was estimated over a period from 1975 to 1999, with a few gaps in data, for example, during the late-1980s. The pattern of relative production was similar between the two areas, with peak production in the late-1970s and a rapid decline through the 1980s (W. A. Palsson, see Footnote 8). During the 1990s, the relative production was somewhat constant in both areas, ranging from 21.5 to 36.9% (mean of 24.4%) in the North and 10.5 to 28.7% (mean of 20.1%) in the South. While Palsson's estimate of egg production may serve as an index of egg production by the population, neither age nor size selectivity by the fishery was estimated. Thus, the estimates are a measure of egg production of fish that were vulnerable to the fishery. Exploitation rates typically increase until a certain age or size and then either do not change or decrease with size or age. Selectivity also can change with time if fishing methods and/or locations change. The unknown nature and dynamics of selectivity could have important impacts on the relationship between trends in Palsson's estimates and trends in egg production by the whole population. Regardless of these concerns, the evidence of considerable decrease in abundance of copper rockfish in the DPS indicates that egg production also decreased considerably. Estimates of egg production are not available for the other rockfish species in greater Puget Sound.
The BRT has provisionally identified at least two copper rockfish DPSs outside of the Puget Sound proper DPS. One of these contains the petitioned areas of North Puget Sound, including the San Juan Islands and Strait of Juan de Fuca. The provisional boundaries of this DPS, which is termed the northern Puget Sound DPS, also include the Canadian Gulf Islands and extend to an uncertain degree further north into the rest of the Georgia Basin. The third DPS is found on the coast and may extend as far south as California and as far north as Alaska. The boundary between the northern Puget Sound DPS and the coastal DPS is provisionally placed at Cape Flattery. However, the level of resolution of available data do not allow determination of this boundary with the same degree of certainty that is associated with the boundary at Admiralty Inlet between the Puget Sound proper DPS and the northern Puget Sound DPS. This section of the status review addresses risk to the petitioned northern Puget Sound DPS. The uncertainty of the western and northern boundaries of this DPS are consistent with the genetic data which show differentiation by distance but not sharp breaks which might indicate clear DPS boundaries. Accordingly, information regarding abundance, trends and risks will come nearly entirely from U.S. waters of North Puget Sound and more distant information will be considered to be less relevant to the risk faced by copper rockfish in the petitioned area of North Puget Sound.
The primary sources of information on abundance and trends are the trawl surveys, SCUBA surveys, VAT surveys, and fishery data. Each provides information from somewhat different habitats and no population models have been developed to integrate these diverse data sources. Each data source is considered independently here and results are synthesized to the extent possible.
Pacunski and Palsson (1998) and Palsson (W. A. Palsson, see Footnote 8) reported on VAT surveys conducted in the San Juan Islands and the Strait of Juan de Fuca between 1993 and 1996. The population of copper rockfish in North Puget Sound are estimated to be approximately 2,600,000 fish in 1994 (Table 10) (W. A. Palsson, see Footnote 8). The large CV for the population estimate of copper rockfish in the Strait of Juan de Fuca for 1994 does not allow concluding that the 1994 estimate is not significantly larger than the 1996 estimate for this area. Also, the abundance of copper rockfish in North Puget Sound appeared to be about double that of quillback rockfish.
Trawl surveys were conducted frequently in North Puget Sound between 1987 and 1995 (W. A. Palsson, see Footnote 8). A survey of the Gulf of Bellingham was also done in 1997. The estimated population number of copper rockfish in 1987 was 72,000 fish (Fig. 30). In 1989 and 1991, no copper rockfish were collected. The population was estimated to be approximately 17,000 in 1995. The population estimate for copper rockfish in the Gulf of Bellingham in 1997 was about 6,000. The biomass values of copper rockfish for this period showed a similar pattern (Fig. 31).
SCUBA data are available from one fished and one unfished site in the San Juan Islands (Table 3). These data show a lower density of copper rockfish at the fished site, but the difference between fished and unfished sites is much less than in Puget Sound proper. The magnitude of decline at the fished site (<50% decline) is not inconsistent with the normal consequences of sustainable harvest rates if the density at the unfished sites have been relatively unaffected by fishing in adjacent areas.
Fishery data also indicate that copper rockfish remain common in North Puget Sound but have experienced some decline. During 1980-1999, copper rockfish comprised 30-60% of the recreational catch of rockfish in this area, and the trend has increased over time (Fig. 21). The catch per trip of all rockfish species fluctuated between 0.6 and 1.0 with no apparent trend after a decline from higher levels in the late-1970s. The length frequency data from the recreational fishery catch show a decline in the average length (Figs. 32, 33) due to a reduction in the fraction of fish greater than 45 cm. Most of this decline occurred prior to 1985. Palsson (W. A. Palsson, see Footnote 8) used length-specific fecundity and maturity information to transform these length frequencies into estimates of relative egg production. During the 1990s, Palsson calculates egg production to have declined to a mean of 24.4% of previous levels. At this time there is not sufficient information to compare current egg production to the levels that would be expected from an unfished population. If the egg production level of the late-1970s is close to the "unfished" state, then the recent 24.4% level is only slightly below the 25% level used as a threshold for overfished (depleted) determination of rockfish stocks on the coast (see the following section on Population Declines of Greater Puget Sound Rockfish and Sustainable Fishery Targets in this document). Such a threshold is not linked to a risk of extinction, rather it is the level from which the population is expected to be able to rebuild to optimum levels within 10 years through sufficient reduction in harvest.
Some information exists on trends for copper rockfish outside of the North Puget Sound area. Richards and Cass (1987) reported decreases in the size of rockfish stocks in the Strait of Georgia. They discounted lack of recruitment as a cause and invoked fishing as the primary factor. Subsequently, the catch-per-effort of the combined quillback and copper rockfish complex has declined moderately in the Queen Charlotte Strait, Campbell River, and Gulf Islands (Fig. 24).
Within the potential coastal DPS for copper rockfish, Marine Recreational Fisheries Statistics Survey (MRFSS 2000) data for recreational catches within three miles of the Pacific Coast for 1993 to 1999 suggest a gradual decline in catch from 123,000 in 1993 to 61,000 in 1995, with a modest increase in 1996 to 86,000 and a decrease to 29,000 in 1997. Since 1997, a gradual increase was observed to 73,000 in 1999 (Fig. 34). Length-frequency patterns for these years were fairly similar, with a modal length around 7 to 8 inches (18 - 21 cm) (Figs. 35, 36, 37).
The BRT assessed risk in three categories defined in Wainwright and Kope (1999) which are: abundance and trends in population, productivity and variability, and habitat quality change. The members of the BRT were asked to rate these risks from 1 to 5 with 1 representing very low risk and 5 as high risk of extinction in the near future due to this factor.
For the Puget Sound proper DPS of copper rockfish, abundance was rated by the BRT as a modal score of 2. A score of 2 represents "Low risk. Unlikely that this factor contributes significantly to the risk of extinction by itself, but some concern that it may in combination with other factors." The range was between 2 to 3. A rating of 3 represents "moderate risk. This factor contributes significantly to the long-term risk of extinction, but does not in itself constitute a danger of extinction in the near future". For trends in abundance, the modal score was 3. The BRT was in consensus on this score, so there is no range of scores to report. For changes in habitat quality, the modal score was 2 with a range from 2 to 3. As a reference, other species that have been subsequently recommended for listing generally have been in the 3 to 5 score range for each factor.
For copper rockfish in North Puget Sound, the BRT considered the risk of extinction to be no greater than the risk to copper rockfish in the Puget Sound proper DPS. This is primarily due to the substantial numbers (2 million in the VAT survey alone) of copper rockfish inhabiting the North Puget Sound area and the lack of dramatic downtrend in most of the indicators for this area. Further, the reductions in the recreational fishery bag limit and voluntary establishment of some no-take marine reserves have presumably reduced current fishing mortality below the level which occurred during the moderate population declines over the past 20 years. These factors cannot be quantified with existing information and a quantitative forecast of likely future population trends in North Puget Sound in not undertaken. However, the fishing mortality rates that would be used in those projections probably would be less than the fishing mortality rates associated with previous declines in population abundance.
Musick et al. (2000) have developed a method that compares information pertaining to the productivity of the DPS to criteria based on productivity of species and their resiliency of populations. Because the risk matrix process assisted the BRT in determining that the Puget Sound proper DPS of copper rockfish is not in danger of becoming extinct in the forseeable future, the BRT utilized this method to assess whether the species might be "vulnerable" "(of special concern), not necessarily endangered or threatened severely, but at possible risk of falling into one of these categories in the near future" (Musick et al. 2000). The information available for use in this method is the time at maturity (Tmat) and the maximum age of fish (Tmax). Both of these parameters result in a "very low" productivity parameter (Table 12). The BRT then utilized this rating to determine the decline threshold of the population and compare it with the decline threshold of Puget Sound proper copper rockfish (Table 13). As the decline in population in the Puget Sound proper DPS appears to be in the 70- 80% range over 25 years, the BRT agreed that copper rockfish would meet the American Fisheries Society (AFS) criteria for "vulnerable" and should be monitored in the future for further evidence of decline. There is not sufficient information to determine if copper rockfish in North Puget Sound have fallen below the same quantitative threshold. They have declined to some degree and should be monitored to guard against further declines that would pose greater risk.
Bearing the results of the above comparisons in mind, the BRT considered whether Puget Sound proper copper rockfish DPS was in danger of extinction, likely to become in danger of extinction or not likely to become in danger of extinction. The majority of the BRT concluded that the Puget Sound proper DPS of copper rockfish are neither at risk of extinction nor likely to become so. However, most members expressed concern they could not entirely rule out the possibility that this species at present is likely to become in danger of extinction. The BRT also concluded that this DPS met the IUCN criteria to be considered vulnerable. The BRT agreed that populations of this species had declined over the last 3 or 4 decades, with over_harvesting being a likely major factor. Nevertheless, the populations in the DPS had appeared to be stable over the last five years, and the lower population numbers in this DPS compared to the larger numbers in North Puget Sound are roughly in proportion to the greater amounts of kelp and high-relief habitat in North Puget Sound. The BRT considered the risk to copper rockfish in North Puget Sound to be no greater than the risk to copper in Puget Sound proper. The BRT also expressed caution that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased extinction risk for copper rockfish in these DPSs.
Quillback rockfish have been relatively abundant in Puget Sound proper (Bargmann 1977). Three primary methods are used to assess the abundance of rockfish in greater Puget Sound and San Juan Islands (North Puget Sound). One method involves a video-acoustic technique (VAT) using a remotely-controlled video camera mounted on a platform to survey habitat and associated fish species on potential reef habitats (Pacunski and Palsson 1998). The videos are later viewed in a quantitative manner and estimates of population density were calculated. Another method involves underwater surveys by SCUBA divers of reef habitat. The third method uses standard bottom-trawl techniques to estimate populations based on catch data and surface area trawled. The underwater visualization methods estimate rockfish populations on rocky reefs, their preferred habitat; whereas, trawls sample low-profile habitats that are generally not preferred by quillback rockfish.
Pacunski and Palsson (1998) and Palsson (W. A. Palsson, see Footnote 8) reported on VAT surveys conducted between 1993 and 1996. Although these data are several years old, they do give some indication about the relative abundance of the three rockfish populations in near shore reef habitats (0 to 38 m) in North Puget Sound and Puget Sound proper. The population of quillback rockfish in Puget Sound proper is estimated to be approximately 330,000 fish in 1995-1996 (Table 10).
While Palsson (W. A. Palsson, see Footnote 8) noted that quillback rockfish were not found at numerous VAT sites in areas with apparently suitable habitat in Puget Sound proper, they were found at numerous areas with sites having similar habitat (Fig. 28). With exception of the southern most part of Puget Sound proper, quillback rockfish were found in areas of the Sound with predominantly rocky-reef habitat, although quillback rockfish were not found in some of the individual sites containing apparently suitable habitat within these areas (Figs. 28, 29).
One fishery independent investigation of population trends in Puget Sound proper was conducted by Matthews (1990) and Palsson (W. A. Palsson, see Footnote 14). Matthews (1990) started the trend analysis by conducting monthly SCUBA surveys of rockfish inhabiting four reef areas in the Main Basin of Puget Sound proper in 1987 and 1988. Palsson continued the analysis by duplicating her methods at the same reefs in 1995-1997. A major reduction (by approximately 85%, p#0.05) in quillback rockfish numbers was observed between 1987-1988 and the mid-1990s (Table 11).
Another indicator of population trends is the trawl survey. Because of the preference of quillback rockfish for high-relief structures, such surveys have limited value for estimating population abundance. However, Puget Sound proper has a limited amount of such structures (containing primarily unconsolidated bottom sediments) and the surveys included all habitats from five fathoms to the deepest portions of greater Puget Sound, therefore trawl surveys may be of some use in estimating trends in population abundance. Trawl surveys were conducted periodically in the main stem of Puget Sound proper between 1987 and 1995 (W. A. Palsson15). The estimated number of quillback rockfish in 1987 and 1989 were similar, 1,153,000 and 1,055,000, respectively (Fig. 38). In 1991, this value declined to 668,000, and gradually increased to 766,000 in 1995. The biomass values of quillback rockfish for this period showed a similar pattern (Fig. 38).
The length-frequency characteristics of recreationally-caught quillback rockfish from Puget Sound proper remained relatively constant between 1975 and 1999 (W. A. Palsson, see Footnote 8). The average length during this period varied between 31 and 34 cm (Fig. 39).
At least two quillback rockfish DPSs are provisionally identified outside of the Puget Sound proper DPS. One of these contains the petitioned areas of North Puget Sound, including the San Juan Islands and Strait of Juan de Fuca. The provisional boundaries of this DPS also contains the Canadian Gulf Islands and extend to an uncertain degree further north into the rest of the Georgia Basin and toward the coast. The third DPS is found on the coast and may extend as far south as California and as far north as Alaska. The boundary between the northern Puget Sound DPS and the coastal DPS is provisionally placed at Cape Flattery, but the level of resolution of available data do not allow determination of this boundary with the same degree of certainty that is associated with the boundary at Admiralty Inlet between the Puget Sound proper DPS and the northern Puget Sound DPS. Here, attention is focused on the risk to the petitioned northern Puget Sound DPS. The uncertainty of the western and northern boundaries of this DPS are consistent with the genetic data which do not show additional sharp breaks which might indicate clear DPS boundaries. Accordingly, information regarding abundance, trends and risks will come nearly entirely from U.S. waters of North Puget Sound and more distant information will be considered to be less relevant to the risk faced by quillback rockfish in the petitioned area of North Puget Sound.
The primary sources of information on abundance and trends are the trawl surveys, SCUBA surveys, VAT surveys, and fishery data. Each provides information from somewhat different habitats with an uncertain degree of overlap in estimated population abundance and no population models have been developed to integrate these diverse data sources. These data sources are considered independently and results are synthesized to the extent possible.
Pacunski and Palsson (1998) and Palsson (W. A. Palsson, see Footnote 8) reported on VAT surveys conducted in the San Juan Islands and the Strait of Juan de Fuca between 1993 and 1996. The population of quillback rockfish in North Puget Sound are estimated to be approximately 1,000,000 fish in 1994 (Table 10) (W. A. Palsson, see Footnote 8). None were observed in the Strait of Juan de Fuca in 1994 and 141,000 fish were estimated to be in that area in 1996.
Trawl surveys were conducted frequently in North Puget Sound between 1987 and 1995 (W. A. Palsson, see Footnote 15). A survey of the Gulf of Bellingham was also done in 1997. The estimated population numbers of quillback rockfish ranged from 30,000 to 363,000 fish (Fig. 38) plus 106,000 in the Gulf of Bellingham in 1997.
SCUBA data are available from one fished and one unfished site in the San Juan Islands (Table 3). These surveys observed no quillback at the fished site and an average of 1.0 fish per transect at the unfished site. Given this low level of occurrence and the limited number of sites sampled, it is unlikely that these data are informative regarding the status of quillback in the North Puget Sound area.
Fishery data indicate that quillback rockfish remain common in North Puget Sound but have experienced some decline. During 1980-1999, quillback rockfish comprised 20-40% of the recreational catch of rockfish in this area, and the trend has decreased over time (Fig. 21). The catch-per-trip of all rockfish species fluctuated between 0.6 and 1.0 with no apparent trend after a decline from higher levels in the late-1970s. The length-frequency data from the recreational fishery catch show a decline in the average length (Fig. 40) after 1989, but no further decline during the 1990s.
Some information exists on trends for quillback rockfish outside of the North Puget Sound area. Richards and Cass (1987) reported decreases in the size of rockfish stocks in the Strait of Georgia. They discounted lack of recruitment as a cause and invoked fishing as the primary factor. Subsequently, the catch-per-effort of the combined quillback and copper rockfish complex has declined moderately in the Queen Charlotte Strait, Campbell River, and Gulf Islands (Fig. 24).
Mark Wilkins16 provided data on population trends of quillback rockfish collected in the Alaska Fishery Science Center's Triennial Shelf Survey of coastal waters west of Vancouver Island. The data may not be reflective of the population trends for quillback because their shallowest station is 30 fathoms; nevertheless, these data may be the best data available for quillback in the coastal areas near greater Puget Sound. Between 1983 and 1995, the estimated biomass (t) varied between 50 and 70 t. However, in 1998, the value increased to about 150 t (Fig. 41).
The BRT assessed the three main risk categories as described previously. For the Puget Sound proper DPS of quillback rockfish, abundance was rated by the BRT as a modal score of 2. A score of 2 represents low risk defined as "Unlikely that this factor contributes significantly to the risk of extinction by itself, but some concern that it may in combination with other factors." The BRT was unanimous so there is no range to report. For trends in abundance, the modal score was 3. A rating of 3 represents "moderate risk. This factor contributes significantly to the long-term risk of extinction, but does not in itself constitute a danger of extinction in the near future". The BRT was also in consensus on this score, so there is no range of scores to report. For changes in habitat quality, the modal score was 2 with a range from 2 to 3. As a reference, other species that have been subsequently recommended for listing generally have been in the 3 to 5 score range for each factor.
For the quillback rockfish in North Puget Sound, the BRT considered the risk of extinction to be no greater than the risk to quillback in the Puget Sound proper DPS. This is primarily due to the substantial numbers (about 1,000,000 in the VAT survey alone) of quillback rockfish still inhabiting the North Puget Sound area and the lack of dramatic downtrend in most of the indicators for this area. Further, the reductions in the recreational fishery bag limit and voluntary establishment of some no-take marine reserves have presumably reduced current fishing mortality below the level which occurred during the moderate population declines over the past 20 years. These factors cannot be quantified with existing information, so a quantitative forecast of likely future population trends in North Puget Sound is not attempted here. However, the fishing mortality rates that would be used in those projections probably would be less than the fishing mortality rates associated with previous declines in population abundance.
The BRT utilized the Musick et al. (2000) method as was described previously to assess whether the species might be "vulnerable" The information for quillback rockfish available for use in this method is the time at maturity (Tmat) and the maximum age of fish (Tmax). Both of these parameters result in a "very low" productivity parameter (Table 12) which is associated with a decline threshold of 70% (Table 13). Quillback rockfish have declined 86% in the SCUBA survey, so the BRT concluded that the Puget Sound proper DPS of quillback rockfish would meet the criteria for "vulnerable" and should be monitored in the future for further evidence of decline. Although the BRT cannot determine if quillback rockfish in North Puget Sound have fallen below the same quantitative threshold, they have declined to some degree and should be monitored to guard against further declines that would pose greater risk. The BRT, bearing in mind the above results regarding risk, considered whether the Puget Sound proper DPS of quillback rockfish was in danger of extinction, likely to become in danger of extinction or not likely to become in danger of extinction. The majority of the BRT concluded that the Puget Sound proper DPS of quillback rockfish are neither at risk of extinction nor likely to become so. However, most members expressed concern that they could not rule out the possibility that this species at present is likely to become in danger of extinction. The BRT also concluded that this DPS met the IUCN criteria to be considered vulnerable. The BRT agreed that populations of quillback rockfish had, according to a SCUBA survey, declined to 14% of its 1988 population size, with over_harvesting being a likely major factor. Nevertheless, the populations in the DPS had appeared to be stable over the last five years, and the lower population numbers in this DPS compared to the larger numbers in North Puget Sound are roughly in proportion to the greater amounts of kelp and high-relief habitat in North Puget Sound. The BRT considers the risk to quillback rockfish in North Puget Sound to be no greater than the risk to quillback in Puget Sound proper. The BRT also expressed the same caution as they did with copper rockfish, that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased extinction risk for this species in Puget Sound proper and North Puget Sound.
Pacunski and Palsson (1998) and Palsson (W. A. Palsson, see Footnote 8) reported on VAT surveys conducted between 1993 and 1996. Although these data are several years old, they do give some indication about the relative abundance of the rockfish populations in near shore reef habitats (0 to 38 m) in North Puget Sound and Puget Sound proper. Within Puget Sound proper, populations of brown rockfish appear to be about 10% of those for copper and quillback rockfish. The population of brown rockfish in Puget Sound proper is estimated to be approximately 100,000 (10).
Another fishery-independent investigation of population trends in Puget Sound proper was conducted by Matthews (1990) and Palsson (W. A. Palsson, see Footnote 8). Matthews (1990) started the trend analysis by conducting monthly SCUBA surveys of rockfish inhabiting four reef areas in the Main Basin of Puget Sound proper in 1987 and 1988. Palsson continued the analysis by duplicating her methods at the same reefs in 1995-1997. Densities of brown rockfish appeared to be increasing by a factor of approximately 6 during this time period (Table 11). The mean densities from 1987-1988 were significantly different (p#0.05) from the values found in 1995-1997.
Another indicator of population trends is the trawl survey. Trawl surveys were conducted periodically in the main stem of Puget Sound proper between 1987 and 1995 (W. A. Palsson, see Footnote 15). The estimated number of brown rockfish in 1987 was 761,000 (Fig. 42). In 1989, this value declined to 63,000, and declined further to 23,000 in 1991. The estimated number of brown rockfish rose slightly to 30,000 in 1995. The biomass values of brown rockfish for this period showed a similar pattern (Fig. 42).
Recreational catch data from the MRFSS can also provide information on possible population trends in greater Puget Sound. Unfortunately, this database does not distinguish between catches from North Puget Sound and Puget Sound proper. Because brown rockfish are found primarily in Puget Sound proper, MRFSS (2000) results for Inland Waters Washington are restricted primarily to this DPS. Data for years 1996 to 1999 show variable recreational catches ranging from 800 to 6,000 (Fig. 43). Highest catches were in 1997 (6,000) and 1999 (4,000), and the lowest catches were in 1998 (800) and 1996 (1,800). Length-frequency patterns were roughly similar for all the years except 1998, but this anomaly may be related to the small sample size in 1998 (Fig. 44).
Brown rockfish are uncommon in North Puget Sound. They were not detected in VAT surveys (Pacunski and Palsson, 1998 and W. A. Palsson, see Footnote 8) in the San Juan Islands in 1994 and 1995, but small numbers were detected in the Strait of Juan de Fuca in 1996 (Table 10).
Trawl surveys were conducted annually in North Puget Sound between 1987 and 1995 (W. A. Palsson, see Footnote 15). A survey of the Gulf of Bellingham was also done in 1997. The estimated number of brown rockfish in 1987 was 16,000 (Fig. 42). No brown rockfish were collected in subsequent surveys in North Puget Sound.
Brown rockfish are rare on the coasts of Oregon and Washington (Jim Golden17). Although this species is relatively common in the coastal waters of central and southern California, Pearson (2000) reported that landings by recreational fishers off California had "declined in recent years." He also noted that "commercial landings declined sharply after 1981 and then increased after 1990." Love et al. (1998) used impingement rates of rockfish on screens mounted on seawater intakes for cooling systems of coastal electric generating stations in southern California to monitor population changes. Over a period from 1977 to 1993, maximum rates of brown rockfish impingement were observed in 1980, with a steady decline until 1984, after which impingement was extremely low or absent.
The BRT assessed the three main risk categories as was described previously. For the Puget Sound proper DPS of brown rockfish, abundance was rated by the BRT as a unanimous modal score of 2. A score of 2 represents "Low risk. Unlikely that this factor contributes significantly to the risk of extinction by itself, but some concern that it may in combination with other factors." For trends in abundance, the modal score was also 2. A rating of 3 represents "moderate risk. This factor contributes significantly to the long-term risk of extinction, but does not in itself constitute a danger of extinction in the near future". The range of scores was between 2 and 3. For changes in habitat quality, the unanimous modal score was 2. As a
reference, other species that have been subsequently recommended for listing generally have been in the 3 to 5 score range for each factor.The BRT utilized the Musick et al. (2000) method as was described previously to assess whether the Puget Sound proper brown rockfish DPS might be "vulnerable" The information for brown rockfish available for use in this method is the time at maturity (Tmat) and the maximum age of fish (Tmax). Both of these parameters result in a "very low" productivity parameter (Table 12). The BRT then utilized this rating to determine the decline threshold of the population and compare it with the decline threshold of Puget Sound proper brown rockfish. (Table 13). The population in the Puget Sound proper DPS is not clear and is often contradictory. However, due to the small range of the species within the Georgia Basin and the large geographical disjunction in distribution, the BRT agreed that the Puget Sound proper DPS of brown rockfish would meet the criteria for "vulnerable" and should be monitored in the future for further evidence of decline.
The BRT used methods and criteria from Wainwright and Kope (1999) and Musick et al. (2000) to organize information regarding risk to the Puget Sound proper DPS of brown rockfish. They considered whether the species was in danger of extinction, likely to become in danger of extinction or not likely to become in danger of extinction. A majority of the BRT concluded that brown rockfish in Puget Sound proper are neither at risk of extinction nor likely to become so. Factors in this decision included the increasing numbers of brown rockfish observed in SCUBA surveys in central Puget Sound proper during the late-1990s, stable estimated population sizes observed in trawl surveys in the main stem of Puget Sound proper during the 1990s, and the increased relative percent of brown rockfish in the composition of recreationally-caught rockfish during the late-1990s. Moreover, brown rockfish are more habitat generalists and consume a wider range of prey species, making them more adaptable to the types of intertidal and subtidal habitats and associated food organisms available in the DPS. However, most members also expressed concern that they could not entirely rule out the possibility that this species is at present likely to become in danger of extinction. The BRT also concluded that this DPS met the IUCN criteria to be considered vulnerable. The BRT considered brown rockfish in North Puget Sound to be associated with the Puget Sound proper DPS and to be vagrants from that DPS. The BRT expressed the same caution as they did with copper and quillback rockfish, that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased risk of extinction for brown rockfish in Puget Sound proper.
Rockfishes of the genus Sebastes have been harvested by commercial and recreational fishermen along the West Coast of North America for well over a century. Today, management authority over rockfish fisheries along the West Coast of the United States, including specifically the States of California, Oregon, and Washington, resides principally with the Pacific Fishery Management Council (PFMC). This organization was created by Congress in 1976 as part of the Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA), the legislation that originally established a 200 mile extended economic zone (EEZ) surrounding the nation's coastline. Because the spatial distribution of most rockfishes broadly overlaps both state and federal jurisdictions (i.e., 0-3 miles and 3-200 miles, respectively), the PFMC works to ensure that management measures that regulate rockfish catches are consistent throughout all U.S. West Coast waters. Significantly, the inland waters of Puget Sound proper and North Puget Sound were excluded in the original language of the MSFCMA of 1976.
For west coast groundfish populations, including over 60 rockfish species, the PFMC created a fishery management plan (FMP) to guide and codify its decision-making. The groundfish FMP has subsequently been amended numerous times to incorporate evolving approaches to the problem of groundfish management, including, for example, the imposition of provisions that established a primarily limited-entry fishery in the early-1990s. More recently, Amendment 11 to the FMP was developed in response to the requirements of the Sustainable Fisheries Act (SFA) of 1997, which re-authorized the original MSFCMA and imposed significant new standards that guide and constrain the management of all the nation's marine fisheries.
The most significant new aspects of the SFA that have affected management of west coast rockfish fisheries were the requirements that the PFMC end "overfishing" when it occurred and to maintain healthy groundfish stocks at population levels that would be expected to produce, over the long-term, the maximum sustainable yield (MSY); such a biomass level is called BMSY. In the implementing legislation, overfishing was defined as any rate of harvest in excess of that which would produce MSY, a rate of fishing that is labeled FMSY. To reiterate, the SFA now requires that all federally-managed stocks be maintained at population levels near BMSY while fishing at rates #FMSY. In certain respects, these two requirements are inherently precautionary because the limit reference points that define "overfishing" and "overfished" are based explicitly on values that would produce MSY. NMFS has developed National Standard Guidelines (NSG) to assist the Councils in development of Fishery Management Plans (FMPs) that are consistent with the SFA. These guidelines recommend that a stock be determined to be overfished when abundance is at levels #½ BMSY. In such instances, the stock must be rebuilt to BMSY within a specified period of time, which largely depends on the life-history characteristics of the stock. Namely, rebuilding must occur within the amount of time that would rebuild the stock in the total absence of fishing, plus one mean generation time, or within 10 years, whichever is smaller.
How have these new regulations affected the PFMC's management of west coast rockfish populations? The answer to this question is that dramatic changes have occurred in the last three years. Since that time the PFMC has re-evaluated its "proxy" estimate of FMSY and has substantially lowered its default harvest rates for groundfish. In addition, language in Amendment 11 to the groundfish FMP created a biomass-based harvest policy that is designed to maintain stocks at or near B40%, which is 40% of the biomass level that is expected to occur in the absence of any fishing, i.e., the virgin biomass B0. Based on theoretical arguments, the B40% level is considered a reasonable surrogate estimate for BMSY, which can be very difficult to estimate with accuracy. In addition, Amendment 11 defined the overfished threshold for groundfish stocks to be 25% of B0 in cases where the BMSY level cannot be determined. Based on that criterion, four rockfish stocks have now been declared overfished and rebuilding plans have been developed and implemented - for example, bocaccio (S. paucispinis), Pacific ocean perch S. alutus), cowcod (S. levis), and canary rockfish (S. pinniger). In addition, based on information developed in stock assessments that were conducted in 2000, both widow (S. entomelas) and dark blotched rockfish (S. crameri) will be declared overfished in 2001. In all cases, the rebuilding analyses indicate that recruitment levels are sufficient to begin to rebuild these stocks as long as the fishery harvest is reduced.
It is revealing to examine the extent of decline that occurred among west coast rockfish stocks, before corrective action was taken. For example, S. Ralston18 presented results in Figure 45 show that bocaccio has declined to a very low level of abundance, equal to about 2% of B0. However, based on projections presented in the bocaccio rebuilding plan, which was developed after the population was declared overfished, the stock is expected to recover to 40% of B0 within 37 years if the annual harvest rate is held to no more than 3% of the exploitable stock. Even with these very austere cuts, the bocaccio rebuilding plan was adopted by the PFMC and the year 2000 harvest was constrained to levels that would achieve rebuilding under the plan. Note that the five other rockfish species that are included in the figure range from extremely unproductive stocks that are in a very depressed condition (e.g., cowcod and canary rockfish) to species that may realistically be expected to recover to BMSY within 10 years (e.g., widow rockfish and Pacific ocean perch).
The path to overfished status varied among these species. Pacific ocean perch was depleted by a large foreign fishery in the 1960s and remained at a low, stable level for many years. Cowcod had no stock assessment until 1999, which finally documented chronic overfishing and stock decline. Bocaccio, canary and widow were among the more closely monitored stocks during the 1990s. Their decline below the target level and into an overfished state is due to a combination of causes including: a harvest policy that was not explicitly precautionary, inadequate information to track and forecast stock trends accurately, and a prolonged period of poor recruitment. Whether this decline in recruitment is primarily due to poor ocean conditions or due to an inherent lack of resilience in these rockfish species cannot be unambiguously determined. In either case, rebuilding of these depleted stocks will be slow as long as the recruitment remains at this low level.
Regardless of the specific details concerning each of these particular stocks, it is clear that human exploitation has the capacity to severely reduce population abundances of Sebastes spp. However, it is also evident that, given sufficient political will, harvests can be reduced to levels that eventually will result in healthy sustainable rockfish fisheries.
Discussions by the BRT indicated considerable concern about declines in
abundance of the three species in the DPS, inadequate data to track current
trends in abundance, the ease of overfishing rockfish in many of their
preferred habitats in the DPS, and the possibility that contaminants may
be adversely affecting productivity. However, declines in abundance appear
to have decreased or stopped since 1995, the species were still widely
distributed in the DPS in 1995, minimal estimates of abundance of each
of the species approached or exceeded 100,000 fish in 1995, and there have
not been any studies that showed that productivity was actually impaired
by contaminants. Because of its concerns, the BRT suggests continued monitoring
of the populations, very conservative if any exploitation, and further
investigation into possible impacts of contaminants.
7 W. A. Palsson, Washington Department of Fish and Wildlife, 16018 Mill Creek Blvd., Mill Creek WA 98012. Pers. commun., September 15, 2000.
8 W. A. Palsson, Washington Department of Fish and Wildlife, 16018 Mill Creek Blvd., Mill Creek WA 98012. Pers. commun., September 26, 2000.
9 T. F. Mumford, Jr., Washington Department of Natural Resources, 1111 Washington St. SE, 4th Floor, Olympia, WA 98504-7014. Pers. commun., December 1, 2000.
10 G. Ylitalo Environmental Conservation Division, Northwest Fisheries Science Center, 2725 Montlake Blvd. E. Seattle, WA 98112. Pers. commun., September, 2000.
11 S. Spencer, Environmental Conservation Division, Northwest Fisheries Science Center, 2725 Montlake Blvd. E. Seattle, WA 98112. Pers. commun., September, 2000.
12 Carla Stehr, Environmental Conservation Division, Northwest Fisheries Science Center, 2725 Montlake Blvd. E. Seattle, WA 98112. Pers. commun., September, 2000.
13 T. Klinger, University of Washington, School of Marine Affairs, 3707 Brooklyn Ave. N.E., Seattle, WA 98105-6715. Pers. commun., September 14, 2000.
14 W. A. Palsson, Washington Department of Fish and Wildlife, 16018 Mill Creek Blvd., Mill Creek WA 98012. Pers. commun., November 15, 2000.
15 W. A. Palsson, Washington Department of Fish and Wildlife, 16018 Mill Creek Blvd., Mill Creek WA 98012. Pers. commun., September 29, 2000.
16 M. Wilkins, NMFS, AFSC, 7600 Sand Point Way NE Bin C15700, Seattle, WA 98115-0070. Pers. commun., October, 2000.
17 Jim Golden, Oregon Department of Fish and Wildlife, 2030 South Marine Science Drive, Newport Oregon, 97365. Pers. commun., September 27, 2000.
18 S.
Ralston, NMFS Southwest Fisheries Science Center, Santa Cruz Laboratory,
110 Shaffer Rd., Santa Cruz, CA 95060. Pers. commun., October 2000.