Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 7624
Title: Maturity and growth of darkblotched rockfish, Sebastes crameri, along the U.S. west coast
Author: Peter H. Frey, Melissa A. Head, Aimee Keller
Publication Year: 2015
Journal: Environmental Biology of Fishes
Keywords: darkblotched rockfish,maturity,age at maturity
Abstract:

Changes in the reproductive biology of fish stocks over time can affect the accuracy of recruitment estimates used by fisheries managers to determine harvest levels. For heavily depleted species, shifts in parameters such as age and size at maturity may occur over a relatively short time period in response to changes in selective pressure or population density. We examined the reproductive biology of darkblotched rockfish (Sebastes crameri), a commercially and ecologically important groundfish, which is currently listed as ‘rebuilding’ after years of intense overfishing in the 1980s and 1990s. Ovaries and age structures were collected during the 2011 and 2012 Northwest Fisheries Science Center (NWFSC) west coast groundfish bottom trawl survey. We used histological examination to classify oocyte development and maturity stages for this species. Length and age at 50% maturity were estimated as 30.0 cm fork length and 6.0 years, respectively, indicating a 12% and 29% decrease compared to the length and age at 50% maturity previously reported for this stock. This reduction moderately impacted the depletion level of spawning stock biomass in a recent darkblotched stock assessment, demonstrating the importance of periodically updating life-history data used in stock assessment models. Our study also revealed spatial patterns in darkblotched maturity along the coast, including a notable decrease in the proportion of mature fish encountered south of central Oregon, information that is also of interest to assessment scientists.

Description:

 This paper provides an update to female maturity parameters used to assess the U.S. west coast stock of darkblotched rockfish, Sebastes crameri, based on histological analysis of ovary specimens collected during the 2011 and 2012 Northwest Fisheries Science Center west coast groundfish bottom trawl survey.

Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.
Develop methods to use physiological, biological and behavioral information to predict population-level processes.