Top-level predators in Puget Sound

Fishes, birds, and mammals (including humans) serve as top-level carnivores in the Puget Sound ecosystem. With the exception of humans, these organisms have a diet that consists almost entirely of fish or other vertebrates.

sea lions
Photo: Joni Packard, NOAA.

Fish predators

Fish predators at this trophic level include larger size-classes of Chinook salmon, spiny dogfish, some rockfish species, and large pelagic and rocky-reef species. Populations of most species of rockfish in Puget Sound have declined sharply, and most are now conservation targets (PSAT 2004). The depleted condition of many salmon populations is well-known in Puget Sound. Due to their extended range, the factors affecting salmon abundance extend well beyond the lands and waters of Puget Sound. Lingcod (Ophiodon elongates) is another voracious predator that forages near rock outcroppings and underwater structures. It utilizes a set of 18 sharp teeth to feed on large fish, crustaceans, and mollusks. Puget Sound is also home to the third-largest predatory shark in the world, the bluntnose sixgill shark (Hexanchus griseus), that grows up to 15 feet in length and can be found in the region year-round.

Bird species

Common bird species in the top trophic level are piscivorous (fish-eating) birds such as rhinoceros auklet, pigeon guillemot, common and red-throated loons, horned grebes, marbled murrelets, glaucous-winged gulls, and Caspian terns (Nysewander et al. 2001; Bower 2004; Lance and Thompson 2005; Litzow et al. 2004). In Puget Sound, these birds prey primarily on small pelagic fish (Pacific herring, Pacific sand lance, salmonids, threespine stickleback). One striking feature about the birds that prey on pelagic fish is that many of them have experienced dramatic declines in abundance. Bald eagles will scavenge from spawned-out adult salmonids but are also predators of many of the piscivorous bird species.


Marine mammals that primarily eat fish include harbor porpoises, Dall’s porpoises, California sea lions, Steller sea lions, and harbor seals. Harbor seals, the most common pinniped in Puget Sound, eat mostly schooling fish such as herring as well as salmon, squid, Pollock, hake, smelt, midshipman, and sculpin. Top-level mammalian predators include humans, orcas, seals and other marine mammals. Killer whales include both the piscivorous ecotype that eats largely adult and sub-adult salmon and the marine-mammal-eating ecotype that eats such species as harbor seals. People, of course, forage at all levels of the food web on prey ranging from algae, eggs, larvae, and invertebrates of all sizes to large food fish such as salmon and rockfish.

About the Author: 
The development of the Sound Science document has been a collaborative process among scientists from a variety of disciplines and institutions throughout Puget Sound. The content reflects the wealth of knowledge in existing plans, research projects and personal expertise. The open dialogue and vigorous discussion about the interactions between components of the ecosystem, key threats to the system and critical science needs is almost as significant as the findings themselves. This document is the product of over 30 authors and almost 100 reviewers from federal, tribal, state, local, non-governmental, and academic institutions across the Puget Sound region. In total, hundreds of natural and social scientists have contributed either as co-authors, through extensive reviews, or by participating in workshops to debate and improve the information. We believe that the resulting content of the document thus reflects the collective views of the broad community of natural and social scientists familiar with Puget Sound. Key contributing agencies: King County Department of Natural Resources and Parks, National Oceanic and Atmospheric Administration (NOAA), Northwest Indian Fisheries Commission, People for Puget Sound, Puget Sound Action Team, The Nature Conservancy, US Environmental Protection Agency, US Geological Survey, University of Washington, Washington State Department of Ecology, Washington Department of Fish and Wildlife, Washington State Department of Health, Washington State Department of Natural Resources.