Our spell of fantastic weather continues and much to our delight, we observed a greater density and diversity of seabirds and marine mammals as the R/V Shimada transited north. We crossed through several visible fronts, where different water masses meet. At frontal boundaries, there are obvious changes in the wave forms at the surface, texture and turbidity of the water. Phytoplankton, zooplankton and forage fishes tend to aggregate at fronts and larger predators like seabirds and marine mammals are attracted to these abundant food resources. Although we expected to observe high densities of birds in and around the productive Columbia River plume, we were no less excited on the afternoon of June 21st to encounter huge flocks of sooty shearwaters in the area, with the largest flock numbering over 10,000 individuals.
The Columbia River plume is a major oceanographic feature in this region with a large and dynamic spatial extent, and it was evident that we were still in plume waters today. While transiting along the shelf break of the Columbia River Line we observed a super pod of around 900 Pacific white-sided dolphins, the first we have seen this trip, along with 40-60 Dall's porpoises and 10-12 humpback whales.
Some species highlights include fin whales, south polar skuas, Murphy's (and other pterodroma) petrels, ancient murrelets, a pomerine jaeger and a leucistic murre! The leucistic murre, an individual lacking the normally dark plumage on the back and wings, was flying alongside a murre with typical plumage. We are looking forward to our final days of seabird and mammal surveys in the Columbia River area and hope this slew of exciting observations continues!
We successfully completed a survey of the Columbia River plume using ISIIS. Over the duration of 10 hours we conducted four north/south cross-sections of the plume with catching both an ebb and flood tide. Salinity values ranged from 18-33 psu. Attached is the plot for the first transect (x axis is distance from start so the values are negative). At first glance our samples consisted mainly of a variety of gelatinous zooplankton (with on very dense layer of Mitrocoma near 20 m depth) and the images were saturated with small phytoplankton and detritus. We did not closely examine the real time images because we were in a shallow area and were concentrating on our flying pattern and bottom depth, however we did spot a good size (~3 cm) fish that Toby Auth believes is a Pacific tomcod (see image).
In the early hours of the morning, the night crew finished sampling their last station. Having completed all the regular grid stations, they had some extra time and filled it with some experimental mid-water trawls. Because of the low rockfish catches in the southern stations, we wondered if juvenile rockfishes were at a different depth than the standard tow depth or if most of the rockfishes were closer to shore than our normal sampling grid. So we fished at three depths, (shallow, standard, and deep) at one Columbia River station where we caught a number of rockfish in our earlier sampling. The shallow tow had 1 juvenile rockfish, the deep tow had 55 juvenile rockfishes, whereas the normal depth caught 131 rockfishes which suggests that we are sampling the bulk of the population. We also did a nearshore tow (~20 km) inside of our nearest station on this transect and we caught 19 rockfishes. We also caught a lot of adult herring, northern anchovy, and smelt that we hadn’t sampled much of before, along with some Pacific butterfish. The dominant taxa in terms of biomass were water jellies (Aequorea sp.) which in normal years are generally distributed farther offshore than this station.
Thanks to great weather throughout the cruise we finished everything earlier than expected and will conduct some additional depth-stratified tows tonight. We also have enough time to complete an ISIIS transect of the Newport Line tomorrow during the day, thus completing the ISIIS transect series of the entire Oregon coast.
The crew just deployed the plankton camera sled ISIIS, which we are towing in a sawtooth pattern shoreward. The ship is presently steaming outside the Columbia River plume in “tuna water” (Sal = 31.9; Temp = 15.5oC); unfortunately no bites yet. It will be interesting to see images of plankton from the ISIIS cameras as we transit through the Columbia River frontal region, probably near Station 3. Transit time is ~ 6 hours.
The primary cruise plan of 10 cross-shelf transects is winding up. The weather has been remarkably calm save for a brief blow on the 18th and we have lost no samples (or cod ends!) due to adverse conditions. Unprecedented! The oceanography across all transects has been very similar except for the varying presence of the Columbia River plume. Salinity gradients indicate weak upwelling at the coast. All nearshore stations had elevated chlorophyll ranging from 4.2 to 25.0 mg/m3 (mean +/- sd = 14.9 +/- 7.2) and bottom DO saturation ranging from 21 to 50%. Offshore, temperatures ranged (north to south) from 12 to >15 oC. We encountered plume-influenced salinities at offshore stations on the Newport and Lincoln City lines, and a strong narrow plume (S=28) on the Tillamook Line between stations 7 and 1. In all, these calm conditions have generated a highly stratified water column in the upper 10 -20 meters that has persisted throughout the cruise. Rather uneventful!
We deployed 76 neuston tows targeting crab megalopae, larval fish, and Velella (by-the-wind sailor). Interest in the hydrozoan is due to the huge abundances observed on past cruises and its propensity to feed on fish eggs. This year megalopae and Velella have been scarce and numbers only picked up in the northern transects. Quite a contrast from previous years, but zeros are numbers too. For the megalopae, comparatively low numbers may be a combination of increased advection due to El Niño and the late June sampling period (later than previous cruises and near the end of the primary crab settlement period). Not sure what explains the low Velella numbers; plenty were reported washed up on Washington beaches in May. Perhaps all the “right-handed” sailors beached and the “left handed” sails advected offshore…. In contrast, larval fish (primarily Pacific saury but at least 4 other species including rockfishes) have been found throughout the sampling. Catches of copepods and krill are also low, but Pleurobrachia comb jellies and salps are unfortunately all too abundant. All in all, a definite contrast to the cruise last year during Warm Blob conditions and a more normal year in 2014.
Food has been superb and I expect all of us will need extra time on the treadmill back on shore.
Yesterday afternoon we crossed over into Washington State to sample our northernmost transect off Willapa Bay. It was like a whole new ecosystem up here – we continued to get the huge catches of age-0 hake (almost 14,000 in one haul and 6000 in another) but the real game-changer was that we finally hit the juvenile rockfish. We got them in all the hauls but one had 385 in total (six or more species but mostly widow rockfish and shortbelly rockfish) which may have been our largest rockfish haul ever. Seems like much more of a diverse fauna up here although the gelatinous taxa are still very abundant up here.
This afternoon we have no cool ISIIS pictures because....we successfully deployed an enormous new piece of gear three times instead. A coupled asymmetrical Multiple Opening Closing Net Environmental Sampling System (coupled MOCNESS) is a really cool fixed frame plankton and small fish sampler that is the only one of its kind in the world. The system consists of 5 MOCNESS-4 nets (7.5-m long × 4-m2 mouth; 800-µm mesh), 5 MOCNESS-1 nets (3-m long × 1-m2 mouth; 153-µm mesh), several environmental sensors, and an electronic flowmeter. Both sized nets are tripped at the same time from the acoustic lab of the Shimada. The nets can be opened and closed at various depths. We had hoped to use this gear every other transect line but some circuitry and software problems early in the cruise prevented the tripping mechanism from functioning properly. Even after we got a new circuit from the manufacturer during the crew exchange near Newport, it still is not functioning properly.
This morning we entered the southern end of the Columbia River plume while sampling on the Tillamook line. Salinity values dropped to 28 psu at the surface in offshore waters.
Tonight we made a decision to skip a transect and proceed to our northernmost transect off of Willapa Bay, Washington. We then plan to head back down to the Columbia River Line where we will hopefully hit the plume closer to the source. If all goes well, we will spend a couple of days on this transect which allows for some fine-scale sampling of the plume fronts with ISIIS and the nets that we have aboard The goal is to run a few transects perpendicular to the plume to capture the influences it has on larval distributions.
In the short ISIIS transect done on this line, we got some beautiful images today including a shell-less pteropod (Corolla sp.) and a Physonect siphonophore. Offshore at ~60 m depth, we passed through an incredibly dense ~2m thick aggregation of shrimp that we believe coincided with a large acoustic signal on the ships radar.
We are one week into our survey now and have been progressing steadily northward. Although there have been little tidbits in the previous reports about the fishing, I have to say that it has been less than exciting so far with the catches. As background, we generally do four midwater trawls an evening with a modified Cobb trawl with a fine-mesh liner. It is towed with the headrope at 30 m and has about a 10 m vertical opening so we are fishing a distinct layer which we expect the juvenile rockfish to be. We could physically do more than 4 tows a day but these tows need to be done when it is completely dark out but unfortunately we are around the longest daylight of the year and moving further north so the amount of time we have to work in is limited.
So what do we catch? Compared to previous years (even last year’s Warm Blob sampling), the catches have been very low. We have caught our main target species, juvenile rockfish, in less than half the tows. Last night was the first time we caught them at all four stations but the catch was very low. Catches of our other target species (young-of-the-year (YOY) Pacific hake and flatfishes) had been fairly low but we did finally get some big catches of YOY hake (50-60 mm) yesterday at our two far offshore stations (>1000 and >10,000 per haul) along the Tillamook Line. The larger catch was associated with a dense layer in the upper 50 m of the water column that was giving off a strong acoustic signal at 38 kHz (see picture). Even the normal mesopelagic species such as lanternfishes and small squids seem to be in lower abundance compared to other years. The only taxa that appear to be increasing is the offshore gelatinous group called pyrosomes. In the past, we hardly got these at all but their abundance started increasing during the Warm Blob last year, but this year it seems to be the highest catch in terms of biomass overall.
We have been scratching our heads trying to figure out what is happening here. We have been getting reports from other vessels (e.g. Ocean Starr) that they are getting larger than normal catches of YOY rockfishes this year. However, they are using a much bigger net, sampling at the surface, sampling during the daytime, and perhaps most importantly sampling much closer to shore. We suspect that the rockfish are in the more productive nearshore coastal zone and avoiding the low productivity offshore waters, unlike previous years. The big catches have occurred off the coast of Washington whereas we have been working off of Oregon which may be less productive this year. The differences may be due to El Niño and the strange weather patterns we are seeing (almost no upwelling favorable winds) so far. We would like to move closer to shore but we are a bit more restricted for fishing in shallow waters. We also want to at least repeat the same stations that we have sampled the last four surveys to facilitate inter-annual comparisons. However, when we finish our regular sampling we hope to do some experimental tows as close to the shore as we can get and also towing the net at different depths in the water column.
The small catches of target species aside, we have caught some interesting taxa including a ragfish and several medusaefish (both of which are likely commensal with large jellyfish) and a large king-of-the-salmon (see pictures). We’ve also collected a variety of invertebrates at most stations including many gelatinous critters, some of which we have not been able to identify with any certainty. We will see how the catch changes tonight as we are now north of the Columbia River off Willapa Bay, Washington.
One week down, one to go! The small boat exchange of scientists went smoothly about 4 miles off of Newport and we are back to work with the new crew. We welcomed on board Daniel Ottman and Paul Chittaro for the rest of the trip.
Today we sampled the Lincoln City Line with ISIIS and appear to have entered less stratified waters - a 20 m deep mixed layer was quite persistent throughout the transect. The fluorometry signal (indicative of phytoplankton biomass) is especially mixed down to ~20 m followed by the chlorophyll max of 0.08 volts- a stark contrast to the past few ISIIS tows that contained thin, dense subsurface layers creating huge peaks in the fluorometry signal (the Heceta Head maximum was 50x our maximum on the Lincoln City Line).
There was a dense but thin layer of Pandalid shrimp (~35 m) in the offshore waters and a deep (~90-100 m) doliolid salp layer as we moved inshore. The latter was of lesser magnitude and less persistent compared to previous observations in the southern lines.
We were able to capture a clear image of the flatfish previously thought to be either a slender sole (Lyposetta excilis) or flathead sole (Hippoglossoides ellasodon). With the help of Toby Auth, we have determined that this beauty is likely a flathead sole!
Finally, we saw our 3rd potential brachiolarian larvae - positive identification to come!
Although the sea is getting a little rougher as a moderate storm passes through, we are having a great time and are excited to see what the change in weather will reveal in the plankton the next few days!
Kelsey and the ISIIS team
We really could not ask for better observation conditions for seabird and mammal surveys up on the flying bridge. We have been mostly observing species that are typical for breeding season off the Oregon coast, with a handful of sightings of common loons, which usually have migrated north by this time of year. The winds have been calm and the seas mostly glassy since we left Newport. These conditions mean we can be confident that we are detecting the vast majority of the birds that come into our 300 m survey quadrant - but it also means that not many birds are up and flying. In fact, the abundance of birds detected on our survey is notably lower than in previous years. Instead, we are seeing quite a few humpback whales (at least 90 sightings). Similar to the 2015 cruise, there were concentrations of humpback whales along the Brookings and Gold Beach lines. Although not in quite the numbers we observed last year, there were some impressively close sightings. Along the Bandon line, we passed right through the middle of a pod of feeding humpbacks, and everyone on the flying bridge was treated to close up views of them surfacing and diving.
Many pelagic seabirds, such as albatrosses, rely on strong winds to fly using a flight style called dynamic soaring. Birds use very little energy while dynamic soaring, instead of flapping, they take advantage of the wind and waves to propel them. When there is no wind, they have to flap their long narrow wings much more often and flying is therefore a much more energetically costly endeavor. We are seeing some general across-shelf patterns in seabird presence, with storm-petrels present and active on the outer shelf during the morning hours. Observations along our mid-shelf transit are mostly of black-footed albatrosses and pink-footed and sooty shearwaters, while nearer to shore we are primarily seeing common murres and gulls.
Because there are a variety of different projects happening on this cruise we are getting the opportunity to re-sample some of the same transects within a few hours. We are excited to explore the spatial and temporal persistence of the seabird and mammal aggregations we are observing. We have been enjoying the calm weather, and were hopeful that we might see some interesting pelagic seabirds as we crossed over Heceta Bank, a well-known seabird hotspot. Alas, the Heceta line and the Newport line were some of the slowest days for bird activity.
As we move north of Newport, the birding picked up - along with the wind. For the first time on this cruise, we lost an afternoon of surveying because the wind conditions but were able to begin surveying again this morning as we returned toward shore on the Lincoln City line. We were rewarded with the most exciting bird of the trip! After passing behind a factory trawler, the FV Island Enterprise, we spotted a Brown Booby flying north following the fishing vessel. Brown Boobies are an unusual, but not unheard of, sighting off the Oregon coast and are a sure sign of warm water conditions.
Bob and I are getting off tomorrow morning via the small boat transfer, and we will certainly miss being on the Shimada. Everyone — the captain and the entire crew — have been really fantastic. Totally accommodating with all of our needs, and really going above and beyond in certain cases (for example, the engineering team helped us fix a broken piston rod that controlled the wings and also fabricate a new side panel that fell off of ISIIS during deployment!)
We sampled for almost 6 hours today on the Bandon Line (offshore —> onshore). Overall, we saw higher fluorometry peaks, lower oxygen at depth (nearshore), and may also have sampled a bit of a freshwater lens coming off the Columbia River plume. We went a little bit further inshore of the actual line end, towards the 50 fathom line, at which we sampled very, very close to the bottom. We had a few technical issues with ISIIS, but nothing that the Shimada engineering crew couldn’t help us solve!
Within the biological data, we saw some very interesting features. First, there was a large, dense patch of mesopelagic (and other) fishes, on the offshore side of the transect, between 80-100 m. In about 6 minutes of sampling (~50 m^3), we saw over 30 larval fish — incredible! These were mostly myctophids, (also called lanternfishes) and we even saw a couple frames where they were quite close to a doliolid nurse (see image here).
We also saw some very striking vertical structuring, which were characterized by layers of small and large diatom chains, doliolids, filamentous marine snow (decay from the bloom), large ctenophores and siphonophores, and then more clumping marine snow. In addition, we went through another dense patch of shrimps and krill (near surface, and nearshore), and large gelatinous zooplankton including Mitrocoma cellularia and Bolinopsis sp.. Very great day for us, especially with the ichthyoplankton. Really validates that key second “I” in the ISIIS name.
We have enjoyed calm seas and light downwelling-favorable winds during the first 3.5 transect lines comprising the southern end of our sample range (42.0-43.5oN). Despite this, upwelled water is present at each of our inshore stations, with surface salinities ranging 32-33 psu and there is a moderate phytoplankton bloom with chlorophyll levels in the 9-10 mg/m3 range. Offshore, maximum chlorophyll concentrations are low (1 mg/m3) and located within subsurface peaks at 30-40 m. At all stations, surface waters are supersaturated with oxygen (>100%), but at the nearshore shelf stations, bottom oxygen saturation ranges from 33-39% at 80 to 100 m depths. We first encountered Columbia Plume-influenced water this morning (S<32; T>14) at the offshore station, and we expect lower salinities at offshore stations as we continue heading north.
Neuston samples have been dominated by Pleurobrachia ctenophores at inshore stations, and so far we have sampled ZERO By-the-Wind-Sailors (Velella velella), in contrast to their wide distribution last year. We have sampled larvae of Pacific saury, rockfish, and Irish lords in the neuston, but few crab megalopae, perhaps not unexpected since we are past the peak settlement season (for Dungeness crab Cancer magister anyway). The first C. magister megalops were found yesterday evening at the inner most station of the Coos Bay Line (see below).
Weather forecasts suggest a few days of strong upwelling winds are in our future - it will be interesting to see how the chlorophyll, oxygen, and biota respond.
All other operations are proceeding normally. Trawl catches continue to be low in the fish department but we are catching lots of interesting gelatinous critters called pyrosomes, that are actually not very gelatinous at all, at the offshore stations, which are definitely indicative of offshore water closer to shore. Will report more on this later. Science team and crew caught some albacore off the back deck this morning, a sure sign of warm (<15 C) water. Looking forward to some yummy tuna poke for dinner!
We are making progress on our second full day of sampling. We worked off of Gold Beach (lat. 43.5 N) in Southern Oregon under mostly clear skies and light winds so we are thankful for that. Not too much in the way of avian activity on the birding transects but we did see a large aggregation of humpback whales as well as some Orcas that passed by fairly close to the ship.
The In Situ Ichthyoplankton Imaging System (with the unfortunate acronym of ISIIS) that was described in the last posting has been generating some interesting data as it undulates up and down across the shelf region on its daily run. The deployments have been accomplished with excellent skills by the deck crew and officers. Curtis Roegner of NOAA took a great time-laspe video of a deployment that we'll post once we overcome a couple technical difficulties (on the land-side). The video that the instrument provides us shows amazing clear images of small and medium sized plankton and their spatial orientation and distribution patterns providing a new tool for looking at plankton in ways never before possible with traditional nets.
Trawling continues at night with still low numbers of rockfish juveniles and flatfishes, but we did hit a patch of hake collecting both young-of-the-year and even some adult individuals nearshore. The age-0 hake do not always occur in our surveys and suggests perhaps some more northerly spawning activity this past winter. We continue to catch lots of midwater fishes (especially offshore) and gelatinous zooplankton in the tows but few crustaceans and larger fishes.
Morale is good so far and the scientists did very well in the Texas Hold ‘Em Poker tourney last night, but I am sure the crew will get them back soon. Food has been outstanding and we may need to indulge in some self-control by the end of the cruise.
The NWFSC has begun its annual Prerecruit and California Current ecosystem survey under highly accommodating weather conditions. We left Newport on Sunday evening (June 12th) with clear skies and light winds and headed slightly north to the Newport Hydrographic Line (NH line) to begin sampling for plankton and ocean measurements as part of the 20 year time-series. Five stations were successfully sampled and then we headed south to the Oregon/California border to begin or regular survey.
Today we finished our first full day of oceanography, plankton, and fish sampling. The fish trawls are conducted at night and we were happy to be able to complete our scheduled 4 trawls with the very limited darkness that we have this time of year. Catches in the trawl were light with some adult hake, several anchovies, flatfishes, and lots of midwater fishes. We only caught 5 juvenile rockfish so far indicating that this year might be similar to last year with low catches, but it’s still too early to tell. Plankton tows nearshore had a lot of phytoplankton and offshore a lot of gelatinous critters, a pattern similar to last year. Some upwelled water was observed near shore and a subsurface chlorophyll maximum is evident.
In collaboration with Dr. Bob Cowen, director of the Hatfield Marine Science Center, and his research group, we’ve added some exciting new sampling gear this year. The In Situ Ichthyoplankton Imaging System (ISIIS) will be deployed during the daytime to determine the cross-shelf, fine-scale distribution of key ichthyoplankton (fish larvae), mesozooplankton (large zooplankton), and microzooplankton (small zooplankton). ISIIS tows will be conducted for 4 to 6 hours on each of the 10 transects used for nighttime trawl sampling. Plankton imagery data is captured with a large camera (50 cm depth of field × 13 cm field of view, 135 L s-1) and a small camera (9 cm depth of field × 4 cm field of view, 9.8 L s-1). The ISIIS is towed at 5 knots in a tow-yo pattern (surface to a maximum of 100 m) and synchronously samples environmental conditions using a suite of sensors, including: CTD, ECO fluorometer, photosynthetically active radiation (PAR) sensor, dissolved oxygen sensor, and mini Doppler velocity log. The data acquisition rate is immense (17 images a second) and will take some time to go through and process in detail, but a quick on board scan of some images showed amazing detail with lots of small plankton and some larval fish viewed so far. We hope to provide some images in future postings so stay tuned.
All science crew doing well and adjusting to life on a moving ship, as the calm seas have helped immensely. Hope to get our complicated schedule down to a routine soon.