Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 9316
Title: The population dynamics of the longnose skate, Raja rhina, in the northeast Pacific Ocean
Author: V. V. Gertseva
Publication Year: 2009
Journal: Fisheries Research
Volume: 95
Pages: 146-153
Keywords: population dynamics, longnose skate, northeast Pacific Ocean, Stock Synthesis 2 ,

The longnose skate, Raja rhina, is the most commonly landed skate species in the northeast Pacific Ocean. It also dominates survey catches in the area. Existing knowledge on skate biology and fisheries suggests that large skate species with late sexual maturation, like the longnose skate, are extremely vulnerable to overfishing and if overfished they are slow to recover. Historically, in the US Pacific Coast skates have not supported directed fisheries, but have been taken as bycatch in other commercially important fisheries. For the past thirteen years landed catches of skates in waters off Washington, Oregon and California significantly increased. Using the Stock Synthesis 2 modelling framework a population model for the longnose skate was developed to assess the current state of the stock and estimate its past dynamics. Model results indicate that the longnose skate spawning biomass has slowly declined since 1915; the current stock biomass is estimated as 66% of its unexploited level. Uncertainty in regards to fishery-dependent data and female maturity parameters was explored through sensitivity analyses. The model results indicate that it is important to conduct species-specific identification in the fishery and monitor discard of longnose skate to improve the accuracy of fishery catch data and make assessment conclusions more robust.

Theme: Sustainable, safe and secure seafood for healthy populations and vibrant communities
Foci: Provide scientific support for setting annual catch limits and measure results of annual catch limit implementation
Provide scientific support to ensure safe seafood for healthy populations and characterize how human activities and climate affect risks from pathogens, chemical contaminants and biotoxins