Hake, Northern stock, Set gillnets
The spawning-stock biomass (SSB) has increased significantly since 2006 and is well above MSY Btrigger. Fishing mortality (F) has decreased significantly over the last decade and has been close to or below optimum associated with maximum sustainable yield (FMSY) since 2011. Recruitment (R) has been around average since 2009.
Stock structure and recruitment
European hake (Merluccius merluccius) is widely distributed over the Northeast Atlantic shelf, from Norway to Mauritania, with a larger density from the British Islands to the south of Spain (Casey and Pereiro, 1995) and in the Mediterranean and Black sea.
They inhabit deep water during daylight, and come to middle depths at night to hunt, feeding on medium-sized fish and cephalopods, they are even known to eat smaller members of their own species (cannibalism). Because hake is a top predator, its abundance has implications on the survival of other species such as blue whiting, horse mackerel and sardine as well as juvenile hake.
Hake spawn from February through to July along the shelf edge, with the main areas extending from the north from the Bay of Biscay to the south and west of Ireland. There are two major nursery areas, one in the Bay of Biscay and the other off the South coast of Ireland.
Data gaps and research priorities
The uncertainty in the assessment is relatively high, with large changes in biomass estimates in consecutive years. The model confidence intervals are an underestimate of uncertainty because they are narrower than inter-annual changes in estimates in consecutive years (ICES 2017).
There is a lack of tuning data for the earlier years of the assessment, for some areas outside of subareas 7 and 8, and for the larger individuals in the population. Given the expansion of the stock into northern areas (ICES, 2017), there is a potential that not all catches are reported for this stock. Biological sampling from these areas is also limited.
The data compilation of this stock is very complicated because it is exploited by several countries and the assessment model configuration is complex. In turn, the assessment model is very sensitive to the data and the settings used. Hence it is extremely important for the quality of the assessment to have the complete data for all the countries on time and in the right format.
ICES. 2015. Report of the ICES Advisory Committee 2015. ICES Advice, 2015. Books 1-11.
Casey, J and Pereiro, J., 1995.European Hake (M. merluccius) in the Northeast Atlantic. In: Hake: Biology, Fisheries and markets. 125–147, (Chapman & Hall, London. ISBN).
ICES 2017. Hake (Merluccius merluccius) in subareas 4, 6, and 7, and in divisions 3.a, 8.a–b, and 8.d, Northern stock (Greater North Sea, Celtic Seas, and the northern Bay of Biscay). ICES Advice June 2017