Fishes Collected by Midwater Trawls during Two Cruises of the DAVID STARR JORDANin the Northeastern Pacific Ocean, April-June and September-October 1972

摘要

During the spring and fall of 1972 the Coastal Fisheries Resources Division,Southwest Fisheries Science Center, conducted two multi-vesselichthyo plankton/midwater trawl surveys (Cruises 7205-JD and 7210-JD) in a region of the eastern Pacific Ocean between 20 deg and 48 deg N latitude, from the coast westward to ca. 145 deg W longitude. Midwater trawling was limited to that part of the sampling pattern occupied by the David Starr Jordan between 20 deg and 31 deg N latitude. The major purpose of these cruises was to increase our knowledge of the limits of spawning of jack mackerel, Trachurus symmetricus, and Pacific saury, Cololabis saira. The first results from these cruises were reported by Ahlstrom and Stevens (1976) who compared catches of fish eggs and larvaetaken by neuston and oblique plankton nets on 7205-JD. They showed that larvae of some fishes (e.g., Pacific saury, flying fishes) reside almostexlusively near the surface, some (e.g., bathylagid smelts, melamphaids)occur exclusively in the water column below the surface, and others (e.g., jack mackerel) occur in both habitats. Another goal of Cruises 7205-JD and 7210-JD was to define the physical-biological environment seaward of the standard California Cooperative Oceanic Fisheries Investigations (CalCOFI) sampling pattern, and, particularly, to increase our knowledge of the distribution and abundance of fish speciesin this region.