Distribution of Dibranchus species (Pisces: Ogcocephalidae) from the Eastern Central Pacific and their relationship with environmental factors

摘要

The geographic and bathymetric distribution of the genus Dibranchus throughout the Eastern Central Pacific was analyzed, using historical distribution records and results from bottom trawls undertaken from 11 research cruises performed in the Mexican Pacific (TALUD project). A total of three species were collected: Dibranchus hystrix (nine specimens, six trawls), Dibranchus spinosus (25 specimens, nine trawls) and Dibranchus spongiosa (134 specimens, 19 trawls). The greatest density of specimens was confined to 800-1200m depth, but they were caught together in a small number of trawls (D. hystrix-D. spinosus, three trawls; D. hystrix-D. spongiosa, one trawl). This work extends the known latitudinal ranges of D. hystrix by 230km, and of D. spongiosa by 650km and provides the first records for D. spinosus and D. spongiosa in the Gulf of California, and for D. hystrix in the Central Gulf of California. Also, the shallowest depth and maximum sizes records of D. hystrix (865m, 148mm SL) and D. spongiosa (479m, 156mm SL) were extended. Dibranchus spongiosa inhabits the shallowest and warmer sites, almost only within the OMZ; while both, D. hystrix and D. spinosus, are able to live in a wide range of DO concentrations, mainly in the deeper and oxygenated zone. These environmental preferences could be related to their distinct geographical ranges throughout the Eastern Pacific.