Ichthyoplankton and euphausiids off the Peruvian coast, autumn 2017

Abstract

 May 27 and June 14, 2017, the Peruvian hake and other Demersal Stock Assessment Cruise 1705-06, R/V Humboldt, took place. A total of 44 zooplankton samples were collected using a 300 μm Hensen net, in vertical trawls with the vessel stationary up to a maximum depth of 50 m. The zooplankton volumes fluctuated between 0.5 and 45.0 mL/sample, those less than 10 mL/sample were located between Puerto Pizarro and Mórrope, while those greater than 10 mL/sample were distributed mainly in the oceanic zone, with coastal nuclei off Salaverry. A total of 11 euphausiid species were determined, with higher densities in the calyptopis and furcilias stages representing 51% and 34%, respectively, of the total abundance. In ichthyoplankton, 40 species were determined, the most frequent being Diogenichthys laternatus (64%), Vinciguerria lucetia (43%), and Engraulis ringens Jenyns (41%) in the total samples. The anchoveta (E. ringens) was the most abundant (3 to 4,896 eggs/m² and 3 to 3,876 larvae/m²) with important nuclei of eggs between Chicama and Salaverry and larvae off Pimentel. The Panama lightfish (Vinciguerria lucetia (Garman)) presented abundances between 9 to 1,728 eggs/m2 and from 3 to 63 larvae/m2, with higher densities off Chicama and Punta Chao and off Pimentel, respectively. Sardine eggs (Sardinops sagax (Jenyns)) had a total abundance of 1,782 eggs/m2 in a station off Puerto Pizarro, while Peruvian hake larvae (Merluccius gayi peruanus Ginsburg) had an abundance of 3 to 18 larva/m2 and were distributed off Los Órganos, at 15 nm from Mórrope and Chicama.