Juvenile Tunas Collected by Midwater Trawling in Hawaiian Waters, July-September 1967

Abstract

Abstract A small-mesh midwater trawl was towed 83 times in Hawaiian waters during July-September 1967. Objectives were to develop techniques for collecting juveniles of skipjack tuna and other scombrids and to provide information on their distribution. A systematic trawling routine was followed in July and August off the island of Oahu. Deep. (100 m) tows were alternated with shallow (20 m) tows during the day (1200–1800 hours), night (2000–0200 hours), and morning (0400–1000 hours) for the first 57 stations. The last 26 stations included tows, primarily at shallow depth, off the islands of Molokai, Lanai, Hawaii, and Oahu. A total of 995 juvenile scombrids, representing six species, was collected. The catch included 578 skipjack tuna (Katsuwonus pelamis), 180 yellowfin tuna (Thunnus albacares), 133 frigate mackerel (Auxis sp.), 46 bigeye tuna (T. obesus), 25 kawakawa (Euthynnus affinis), and 7 albacore (T. alalunga). The largest catches of juvenile tunas were made in the offshore Oahu area about 56 km fr...