1. United States
Harbor porpoises have made a comeback after the banning of gill netting in key coastal communities of California, new research shows. Gill nets are a cheap and effective way for commercial fishers to catch loads of sea bass and halibut by the gills, but they also wreak havoc on other species, including sea otters, some sea birds, and the lesser-known harbor porpoise. The latter exclusively lives in shallow waters. Being unable to detect the nylon mesh using echolocation, the porpoises would frequently drown after getting tangled in gill nets. Aerial surveys for harbor porpoises, which began in 1986, allowed researchers to identify and track four distinct porpoise populations off California’s coast as gill netting bans rolled out over the following decade. The latest assessment of that data shows the groups affected by gill netting have doubled their populations since the bans were put in place, and are now beginning to stabilize. It’s the first documented case of this species rebounding after bycatch from gill nets is eliminated. “Harbor porpoises show that ... they’re capable of recovering. They have a resilience and they will rebound if we just let them,” says Karin Forney, a Monterey Bay-based research biologist at the National Oceanic and Atmospheric Administration. (Los Angeles Times, NOAA Fisheries, Marine Mammal Science)