Visceral Adhesions in High-Seas Salmon

Abstract

Multiple mesenteric and peritoneal adhesions were recorded in sockeye and chum salmon obtained in 1957 through 1964 during the high seas sampling program. These adhesions were more prevalent among sockeye salmon examined during the 1963 summer research cruise in the North Pacific and winter cruise of 1964, with approximately 9 and 25 per cent respectively of the salmon afflicted. Adhesions were rare among chum salmon and not recorded among other salmon species. Of the sockeye with adhesions, most were fish which had spent 2 winters at sea, most were immature at time of capture, and the majority were males. Visceral adhesions among salmonids reported in the literature are reported to be from infections of the nematode Philonema sp. The relationship between Pacific salmon and Philonema is unknown; also unknown is the ultimate effect on salmon of visceral adhesions.