Antarctic canine toothfish
Photographed by Rob Robbins
Antarctic canines are a key species in the Antarctic marine ecosystem, like the "shark" in the Southern Ocean, which is also at the top of the food chain. Canine toothfish, also known as Chilean sea bass, produce antifreeze protein to protect their bodily fluids from freezing in cold waters. Unlike their relative, the tiny coatfish, it is one of the two largest species of fish in the Antarctic fish family, and adult canine toothfish are usually 1.6 meters long and have a 30-year life. Although it is moderately active and can swim upstream into the middle of the seawater, it is usually found in the depths of the seawater. Females and males usually spawn in turn when they are about 16 or 13 years old. The high reproductive age makes the species particularly vulnerable to overfishing. In addition, canine toothfish have lived for a long time in areas that are difficult for researchers to reach, and key questions about the life history of this species are still unknown.
The Southern Ocean lacks many sharks, and other large fish have been found in other ocean systems, so Antarctic canines play a shark-like role in the Antarctic ocean system. They feed mainly on small fish and cephalopods, but also eat invertebrates and even birds. However , they are considered important prey for Weddell seals , killer whales and king squid. Antarctic canine fishing grounds are found in many parts of the Southern Ocean, including the Ross Sea and the Weddell Sea in Southeast Antarctica. Antarctic canine toothfish fisheries are managed, but uncertainty about their life history and role in the food chain makes it difficult to understand the impact of this fishery on the ecosystem.
A growing body of research suggests that top predators play an extremely important role in many ecosystems, and that ecosystems that lose them will undergo obviously alarming changes, and we urgently need more research to unravel the mystery of these bird-eating deep-sea fish.