Analysis of the evolution of hake (Merluccius hubbsi and Merluccius australis) catch and effort by Spanish vessels operating in the Patagonian shelf area since the beginning of this industrial fishery

Abstract

The hake fishery (Merluccius hubbsi and Merluccius australis) is one of the most important ones for Spanish vessels operating in the Southwest Atlantic. Both species are widely distributed along the Patagonian shelf, although M. australis occupies mainly more southern waters. This paper presents a historical review of fishery data on the Spanish fishing fleet operating in the SW Atlantic collected and collated during the EC Study Project 99/016 “Data collection for stock assessment of two hakes (Merluccius hubbsi and M. australis) in International and Falkland waters of the SW Atlantic”, in order to analyse the evolution of catch and effort in the hake fishery since 1983 to 2000. Data on landings and effort by Spanish vessels from 1983 onwards were utilised to study trends and shifts within the fishery. These data were provided by Asociación Nacional de Armadores de Buques Congeladores de Pesca de Merluza (ANAMER), the most important Spanish ship-owners fishing association operating in distant fishing grounds. Catch and effort data collected by observer’s programmes carried out by Instituto Español de Oceanografía (IEO) and the Falkland Islands Government Fisheries Department (FIGFD), as well as by observers provided by the project were used to estimate CPUE by area and season.The data included landings in kgs by commercial size category of hake (both species together) and effort made by vessels appertaining to ANAMER in number of fishing days and number of vessels by vessel size category. Conversion factors obtained by scientific observers onboard of these vessels were used to obtain the whole catch from landings. Total effort of the Spanish fleet was estimated from ANAMER logbooks, assuming a similar pattern for the whole fleet and taking into account the different ratio of ANAMER fleet compared to the total Spanish fleet. An increase of the catches and effort was observed from 1983 to a maximum in 1990 coinciding with the closure of Namibian fisheries. After that, catches and effort decreased corresponding to the development of the Greenland halibut fishery in the NW Atlantic, until its stabilisation from 1993. CPUE showed different patterns of fishing activity by area and season