A seasonal analysis of the nutritional condition of deep-sea macrourid fishes in the north-east Pacific

Of three common macrourids Coryphaenoides armatus and Coryphaenoides yaquinae were collected from 1995 to 1998 at an abyssal station, c . 220 km west of Point Conception, California in the north-east Pacific (4100 m depth). Coryphaenoides acrolepis was collected from 1997 to 1998 in the San Diego Trough (1200 m depth). Energy storage in all three species was primarily in the liver, which was up to 56% lipid (wet mass) and up to 96% triglyceride. No seasonal variation in nutritional condition was found for C. armatus or C. yaquinae . There was, however, a significant increase in muscle water content and liver lipid content and a significant decline in muscle lactate dehydrogenase activity for C. armatus between 1996 and 1998. Potential mechanisms for these interannual shifts are proposed. No seasonal variation in parameters was found for C. acrolepis but a small seasonal periodicity in feeding activity may have existed. The seasonal deposition of phytodetritus in the deep sea is of little or no consequence to these fishes.