Weekly Sea Discovery: Pacific Hake are an Integral Part of B.C.’s Marine Ecosystem
This week we’re featuring a fish that has both economic and ecological importance to the BC coast and marine ecosystem. Pacific hake is the most abundant groundfish in the California Current Large Marine Ecosystems (including the Salish Sea). Groundfish are fishes that are bottom-dwelling (live on, or nearby the seafloor), like rockfishes, codfishes, and flatfishes.
Pacific hake is a predatory groundfish that looks similar to Pacific cod. They eat a diverse diet of krill (shrimp-like crustaceans), crabs, squid, forage fish, and juvenile salmon. Many different species prey on Pacific hake, like seals, birds, sharks, and other groundfish. Through these predator-prey interactions, Pacific hake is a crucial component for energy transfer in the marine food-web.
This abundant groundfish is a nocturnal predator, which is a typical behaviour among hake species. During the day, they live near the seafloor, and at night they travel up to the surface to hunt. Because Pacific hake are a common predator of juvenile salmon and have such large abundances, scientists are studying their impact on declining salmon populations in the Pacific Northwest.
Pacific hake also prey on various species of forage fish, which are a fundamental part of the marine ecosystem. For example, adult salmon feed on forage fish, and the endangered Southern Resident Killer Whales rely on the adult salmon. Therefore, these orcas are indirectly affected by the predation on juvenile salmon and forage fish by Pacific hake (see diagram above). The predators of Pacific hake keep the groundfish’s large abundances in check. If there are not enough predators (like Harbour seals), the Pacific hake will eat more smaller fishes, potentially causing an imbalance.
We can see the incredible interconnections of marine ecosystems in the example of Pacific hake, and how essential these relationships are.