Record of Lophoura unilobulata (Copepoda: Sphyriidae), mesoparasite of Nezumia stelgidolepis (Gadiformes: Macrouridae) in deep waters of the northern coast of Peru

Abstract

Nezumia stelgidolepis is a demersal fish of deep bentopelagic habit, which moves at the top of the shelf slope between 280 and 910 meters of depth. Lophoura is the oldest and most diverse copepod genus of the Sphyriidae family and is represented by 19 species, considered mesoparasites with a high degree of specificity. In order to analyze and describe the ecological relationship between both species, 10 specimens of N. stelgidolepis were collected from Punta Sal, Tumbes (3°51’S - 81°11’W) during the hake survey cruise in autumn 2015. All specimens were fixed in 10% formalin and preserved in 70% ethanol. The fish were found between 450 and 460 meters of depth (45 atmospheres), with a background temperature of 11.3 °C and oxygen of 0.15 mL/L. 60% of the sample was found parasitized by a copepod and only two specimens of N. stelgidolepis were deposited in the Scientific Collection of the Peruvian Marine Research Institute. It can be concluded that Lophoura unilobulata maintains a high degree of adaptability to the complexity of N. stelgidolepis, considering the oceanographic conditions of its habitat. This work represents the second record (after 40 years) for Peru of L. unilobulata in specimens of N. stelgidolepis and the third of this species parasitizing Nezumia in the South East Pacific.