Pacific Halibut feed on a large variety of prey, ranging from invertebrates to small and large fish species. Although these huge flatfish have a body designed to efficiently feed on the ocean bottom, halibut also swim about the water column and feed pelagically, expanding their foraging range and foraging opportunities. They also happen to eat many of the fish species that are important in the diets of the seabirds we study. Halibut diets give us another tool to track forage fish populations.

Since halibut are both pelagic and bottom feeders, their diets give us an indication of fish and invertebrate distribution and abundance in the areas where they are caught. This information is valuable for these reasons:

1. We are able to see where the different prey species live based on where the halibut are caught. These spatial patterns also affect seabirds and what food is available to them;
2. We are able to see changes in halibut diets. These reflect changes in the abundance of their prey in the marine environment and thus also affect seabirds; and
3. We gain a better understanding of the diets for this important sport and commercial fish.

We are assisting scientists at the Alaska Maritime National Wildlife Refuge (AMNWR) with this study. Halibut stomachs are obtained  from sport-caught fish caught during the course of normal charter fishing operations run out of Homer, Alaska. This saves on the cost of scientific sampling and means that halibut are not sacrificed only for research. Our fish biologists have examined most of these stomachs and identified the contents. Monitoring has revealed important information about the interannual presence and absence of capelin and other forage fishes in lower Cook Inlet (for more information or reports, contact Dave Roseneau at AMNWR headquarters in Homer).

Below is a list of prey species we've found in halibut stomachs. Note the surprising number of invertebrates, particularly crabs. An individual halibut often consumes a great number of a single prey item, so it is not unusual to find up to 50 crabs in one stomach!