Distribution of the Midwater Fishes of the Gulf of California

A series of 203 midwater trawl hauls, most of which were discrete-depth samples, was taken at 126 trawling sites along nearly the entire length of the Gulf of California in 1967, 1968, and 1969. The resulting collection of 10,003 adult fishes has been analyzed as a representation of the community of midwater fishes which resides within the Gulf. A total of 39 species from 32 genera and 17 families were taken. In the collection, Triphoturus mexicanus was the dominant form (68%), followed by Vinciguerria lucetia (10.2%), Cyclothone spp. (8.2%), Diogenichthys laternatus (7.2%), and Benthosema panamense (2.8%). The bulk of the midwater community occupied a depth range between 300 and 400 m during daylight hours and from 50 to 100 m at night. The community is composed mainly of tropical forms but its proportional composition is unique to the Gulf. Water mass structure and surface water characteristics are considered as determinants