June 6, 2018 — In the ocean, everything moves. Waves push around vast swaths of saltwater, tides ebb and flow, and over time tectonic rumblings transform the seafloor. With all that movement, marine life travels as well—making the oceans one of the most dynamic ecosystems on Earth. This constant shuffling can make it hard to predict where a particular marine species might be on any given day. But that is exactly what Elliott Hazen, a fisheries scientist from the National Oceanic & Atmospheric Association (NOAA), is trying to do through new modeling software.
Hazen and a team of other fisheries scientists developed EcoCast in an effort to reduce the unintended bycatch of protected marine species while supporting sustainable fisheries; their results were published last week in Science Advances. EcoCast is already being used to allow fishermen exemptions to fish in certain protected areas in California, and NOAA is working on a smartphone app that will give fishermen this dynamic data in real-time.
The team focused on the California Drift Gillnet (DGN) fishery, which targets broadbill swordfish along the U.S. West Coast. The fishery, which has declined in recent years, only brought in 176 metric tons of swordfish in 2017—down from a historical high of 2,198 metric tons in 1985. DGN fishermen use mesh nets that float vertically in the water to catch the swordfish, but the nets often trap additional species—a phenomenon known as bycatch—including the critically endangered Pacific leatherback sea turtle, blue sharks, and California sea lions.
It’s not just an issue of protecting endangered species, explains Gary Burke, a fisherman in California and a member of the Commercial Fishermen of Santa Barbara. “Fishermen don’t want bycatch. It breaks our gear and it’s expensive. So, we like to avoid it.”
EcoCast takes an array of oceanographic variables into account to generate a fluid map that highlights areas where fishermen are likely to find high concentrations of their target species and not the protected species they don’t want to catch.