Towards a spatial integrated stock assessment model for European hake northern stock

Abstract

European hake (Merluccius merluccius) is a key species in the management of several mixed fisheries in the northeast Atlantic where regional spatial management plans are being set up. The wide spatial distribution of hake and the lack of knowledge of some processes involved in its spatial dynamics could hamper the assessment and management of hake. To help understand the processes, we implemented a spatial version of the Stock Synthesis stock assessment model for northern hake, including available data on this stock and the associated fisheries. For the 1978-2012 time series, the model distinguished the Bay of Biscay, the Celtic Sea and a northern area aggregating the West of Scotland and the North Sea. The model considered an agestructured population for each age class and area, a seasonal migration, global recruitment allocated to areas and fishing fleets for each area. Parameters for stock and exploitation spatio-temporal dynamics were estimated by likelihood maximization for each quarter and area. The comparison of spatial and non spatial models goodness of fit showed they were close, although the fit to abundance indices slightly improved with the spatial model. Fishing mortalities, spawning stock biomasses and recruitments were slightly different from the current assessment model estimates, essentially at the beginning and the end of the time series. On average over the time series, fishing mortality estimates relative to the abundance were higher in the Bay of Biscay than elsewhere, spawning stock biomass estimates were higher in the Celtic Sea than elsewhere, and recruitment occurred mainly in the Bay of Biscay. Finally, the final spatial model estimated a strong movement from the northern area to the Celtic Sea. The final spatial model is a step towards a spatial assessment and management of the stock.

Monthly spatial dynamics of the Bay of Biscay hake-sole-Norway lobster fishery: an ISIS-Fish database

“…populations, exploitation and management - we describe this paper’s database parameters and assumptions. We finally describe the calibration procedure (inspired by previous work 21 , 22 ), of which some results are shown in the Technical Validation section. We summarized this workflow in Fig.…”

“… Intercatch: catch observations for 2010–2020 in the Bay of Biscay for hake, at the quarter- métier group scale, and catch observations per class for sole on 2010–2012, and 2010 Norway lobster catch observations per sex and length class 24 , used to describe the inter-annual effort dynamics, to calibrate and validate the model. Estimates of hake abundance per size class in 2010, and hake quarterly estimates of recruitment on 2010–2012 from a northern hake spatial stock assessment model 21 , used to inform hake biology assumptions (named Other 1 in Fig. 1 ).…”

“…Estimates of hake abundance per size class in 2010, and hake quarterly estimates of recruitment on 2010–2012 from a northern hake spatial stock assessment model 21 , used to inform hake biology assumptions (named Other 1 in Fig. 1 ).…”

Identifying partners at sea on contrasting fisheries around the world

“…[27,29,18,11]), account for it in stock management models (e.g. [28]) and discuss management measures based on it (e.g. [9,14]).…”

Genome-wide SNP based population structure in European hake reveals the need for harmonizing biological and management units

“…Observed and expected heterozygosities per group of samples when using all514 or only outlier SNPs. MED: Mediterranean Sea; EBOB: Eastern Bay of Biscay; NWIPs:…”