Distribution and biomass of the main pelagic, neritic, and oceanic resources in the Peruvian marine ecosystem obtained through hydroacoustic cruises (2018)

Abstract

The year 2018 was characterized by environmental oceanographic contrasts in the Peruvian marine ecosystem. We carried out two hydroacoustic cruises, one in the summer, between February 22 and April 6 (Cr. 1802-04), and the other in the spring, between September 27 and November 18 (Cr. 1809-11), onboard the research vessels of the Instituto del Mar del Perú. Both cruises had the support of fishing vessels from the Sociedad Nacional de Pesquería (National Fisheries Society), to increase biological and acoustic sampling. In the neritic zone, the abundant species were anchoveta, longnose anchovy, catfish, and munida lobster, while the jumbo flying squid and vinciguerria were abundant in the pelagic oceanic zone. In 2018, the anchoveta was distributed widely with biomasses of 11.21 million tons in summer and 8.78 million tons in spring. The munida lobster showed high biomass with 4.97 million tons in the summer due to the cold conditions recorded in that period; while vinciguerria was more abundant in the spring with 2.08 million tons, mainly in the south since the oceanic waters were closer to the coast. The highest biomass of jack mackerel was estimated in the spring at 263,779 tons, the abundance of jack mackerel and chub mackerel was not stable due to oceanographic conditions. Longnose anchovy and catfish are coastal species, their highest abundances were recorded in summer with 241,213 tons and 46,717 tons, respectively. For anchoveta, more schools were recorded in spring than in summer, with higher coefficients of variation in morphometric characteristics; while, in summer, they had higher energetic characteristics due to the concentration of schools.