Biota of near-shore waters off Humboldt Bay and Trinidad Head, 1960-1964, as shown by diet of Pacific Salmon

Thesis (M.S.)--Humboldt State University, Fisheries, 1970During 1960-1964 930 salmon stomachs were collected at King Salmon (Humboldt Bay) and Trinidad for the purpose of comparing the feeding behavior of salmon in these two closely adjoining areas of the Pacific Ocean. For the study period anchovies, euphausiids, herring, osmerids and rockfish comprised 95.1 percent of the total food consumed by volume off Trinidad Head and 90.4 percent off Humboldt Bay. \ud Annual changes took place in the animal communities inhabiting the area off Humboldt Bay and Trinidad Head. The dominant food item off Humboldt Bay was anchovies in 1960, euphausiids in 1961, and herring in 1964. The major food item off Trinidad Head was anchovies in 1960, euphausiids in 1961, crab megalops in 1962, osmerids in 1963, and rockfish in 1964. \ud The results indicate a high degree of consistency in the diet of salmon from both areas and lend support to the possibilities of this technique for sampling those organisms on which the salmon feeds. \ud However, the true extent of feeding selectivity of salmon cannot be understood until there is a more comprehensive understanding of plankton populations