Fishery, distribution pattern and biological aspects of the common European squid Loligo vulgaris in the Gulf of Cadiz

Abstract

The common European squid Loligo vulgaris is mainly caught by a bottom trawl fishery in the Gulf of Cadiz (SW, Spain), accounting for 2.6% of the total bottom trawl landings in the area. Squid landings from the bottom trawl fleet represent 99% of the total landings in the Gulf of Cadiz, while only 1% is caught by the artisanal fleet. The squid fishery by bottom trawl shows a clear seasonal pattern, with the higher landings of the species occurring in October and November. L. vulgaris is mainly distributed in the continental shelf, ranging between 15 m and 100 m depth. Biomass and abundance data were estimated from the ARSA bottom trawl surveys annually carried out in the Gulf of Cadiz in spring and autumn. Squid abundances estimated from these surveys were higher in autumn. The species shows a long reproductive period in the Gulf of Cadiz with mature females and males appearing during the whole year. The higher values were recorded during winter and spring. The estimated ML 50 values for females and males were 18.9 cm and 16.3 cm, respectively. L. vulgaris shows a positive allometric growth, with females growing faster than males. The diet of the common European squid was studied from stomach contents collected in the ARSA scientific survey of November 2008. The osteichthyes group was the main component of the diet. Cephalopods and crustaceans were also present in the diet of L. vulgaris.