OPINION: Protecting killer whales in the Bering Sea requires following the science

The recent deaths of killer whales caught and drowned in the nets of the Bering Sea flatfish bottom trawl fishery, otherwise known as the Amendment 80 fishery, is a tragedy. While the Amendment 80 fleet is taking this seriously, NOAA Fisheries, the agency responsible for protecting these killer whales, is failing to follow the science to ensure their survival.

Unconscionably, the agency refuses to recognize that the fish-eating or “resident” killer whales in western Alaska are distinct from other resident orcas south of the Aleutians, as numerous scientific studies have shown. In doing so, the number of killer whales allowed to be killed by the trawl fisheries is artificially inflated, delaying protections kicking in to safeguard these unique whales.

Rather, NOAA Fisheries currently considers all the Alaska resident killer whales to be part of one “stock.” A “stock” refers to a distinct group of marine mammals that live and interbreed together. In the case of Alaska resident killer whales, the current NOAA Fisheries stock structure combines all Alaska killer whales, stretching from the Southeast up to the Aleutian Islands and the Bering Sea. Yet, a landmark genetics study by Kim Parsons and colleagues in 2013 clearly showed that the western Alaska/Bering Sea population of resident killer whales is a unique stock. Photo identification studies, which keep track of numbers by identifying individual killer whales, also support the creation of two Alaska resident stocks. Finally, satellite tagging does not suggest any mixing of the proposed stocks.

While NOAA Fisheries agrees that the current stock structure of killer whales in Alaska needs to be reassessed, 10 years have passed since that seminal 2013 study, and they’ve taken no action to do so. The problem is that stock structure is used to determine the “Potential Biological Removal,” or “PBR,” for each stock. PBR is essentially the number of animals within the stock that NOAA Fisheries believes can be sustainably seriously injured or killed by human activities, called “take” in regulatory speak. Because all of Alaska’s resident killer whales are lumped into one stock, the “take” allowed is unsustainably high. Accurate PBR is critical because stronger protections for marine mammals kick in only once PBR is exceeded.

The unscientifically vast resident killer whale stock organization has resulted in a PBR of 19 whales a year based on an Alaska-wide population estimate of 1,920 whales (PBR is set for this stock at roughly 10% of the population). This means that the Amendment 80 fleet and other commercial fisheries and human activities, like ship strikes, can collectively kill up to 19 killer whales a year before stronger management kicks in. But there are not actually 1,920 killer whales in this unique western Alaska resident population. Instead, there are around 900 western Alaska resident killer whales, and if PBR was set specifically for this unique population, it could be as low as nine killer whales a year, and therefore, stronger protections from fishery bycatch would kick in much earlier.

Let me be clear: Nine human-caused killer whale deaths a year, which in recent years have been predominantly from the Amendment 80 fleet, are far too many and could set the western Alaska resident population on a road to endangerment. None of us want to see this. The revamping of the killer whale stock assessments for Alaska has been a priority for scientists for years, including myself. We have been extremely frustrated that all the available scientific analysis has not been used to reshape the stock assessments.

This is such a critical issue because the majority of the whales dying in trawl nets are females. These females are not only vital for producing young whales and ensuring the population remains vibrant, but they are leaders of the groups and critical for the population’s long-term survival. Resident killer whales are matriarchal, which means that the adult females help ensure the survival of all members of their groups, from their grand-calves to their adult sons. While some whales die in the trawl nets seeking fish, some live to tell the tale of their death-defying fishing trip. As some escape death with full bellies, they will teach other whales to replicate their risky behavior. Be advised, that this problem will not go away, but rather, I am incredibly concerned it will spread like wildfire and lead to an exponential amount of whale deaths.

After catching nine killer whales in their nets this summer, the Amendment 80 fleet decided to switch to different target fish species where they haven’t had killer whale takes. Now, the fleet and scientists are cooperating to design and test net modifications. If they find solutions, Amendment 80 has said they will voluntarily implement them. If they don’t, the slaughter may continue. Regardless, NOAA Fisheries should not count on the Amendment 80 fleet to voluntarily find and implement gear solutions nor stop fishing to protect these killer whales as we move forward.

NOAA Fisheries should step up and support the science and development of solutions, and require their implementation once solutions are found. The agency must also take urgent action to accurately structure Alaska’s resident killer whale stocks to guarantee that PBR is correct and not exceeded.

With additional pressure, focus, and cooperation between scientists, NOAA Fisheries, and the Amendment 80 fleet, these unique killer whales can be afforded the necessary protections to ensure their survival.

Craig Matkin is the executive director of the North Gulf Oceanic Society based in Homer. He is a whale biologist with more than 40 years of Alaska experience.

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