Distribution of grenadiers (Pisces: Macrouridae) in the continental slope of the tropical Eastern Pacific off Mexico

Abstract

Grenadiers (Macrouridae) comprise one of the most diverse deep-sea fish families, however, knowledge about their distribution in the north-central part of the Eastern Tropical Pacific (ETP) is scarce. The distribution patterns of seven grenadiers throughout the Mexican Pacific were described and their relationships with environmental factors were evaluated, using univariate and multivariate analyses. During the Talud project, 3320 grenadiers were caught, using a benthic sledge (extreme coordinates: 16∘49’ N-31∘48’ N, 100∘21’ W-117∘15’ W; depth range: 100–2400 m). Coelorinchus scaphopsis (n = 1699, 203–1158 m) was restricted to warm and oxygenated sites of the northern Gulf of California (GC). Coryphaenoides acrolepis (n = 6, 1318-1448 m) was recorded in temperate and oxygenated sites of the lower slope of the northern portion of the western coast of Baja California (BC), its southern distribution limit. Nezumia liolepis (n = 1363, 534–1600 m) Coryphaenoides anguliceps (n = 32, 745–2103 m), and Coryphaenoides capito (n = 66, 554–1520 m) are widely distributed in the Mexican Pacific; because they are able to live inside and outside of the Oxygen Minimum Zone (OMZ), dissolved oxygen is not a limiting factor in their distributions. Nezumia convergens (n = 7, 1073–162 m) and Nezumia stelgidolepis (n = 147, 554–1418 m) were recorded occasionally, however, both species are common in several ETP locations. The first records of C. capito and N. convergens in BC were reported and the presence of C. anguliceps in the northern BC was confirmed. A taxonomic key is included to distinguish the grenadiers of the Mexican Pacific, and new meristic and morphological data are provided for N. convergens.