Whale Entanglements, Crab Gear, and What Can Be Done?

Whale entangled in crab gear. [Image from NOAA]

The commercial fishery from the Sonoma-Mendocino line to Mexico closed at noon on April 8, and the rest of the commercial fishery, from there to Oregon, will close at noon on Wednesday, April 20. The CDFW is also asking recreational crab fishermen to remove their traps from the water as soon as possible, but no later than April 24. Recreational fishermen will still be allowed to use hoop nets and snares for the remainder of the season. 

“This isn’t something we would have anticipated,” said Ryan Bartling, a senior environmental scientist with the CDFW marine region. “The number of whales we’re seeing for this time of year is well above the average.” In addition to the early migration, Bartling noted that there is also plenty of forage for the animals, including anchovies, sardines, and even krill at the shelf break. With a population that is “definitely recovering” and  five entanglements over a month and a half, Bartling conceded, “We’re in uncharted territory.” Three of the entanglements were confirmed with commercial California Dungeness crab gear, while the other two were “not identifiable, but the gear is consistent with what could be commercial Dungeness crab gear.”

“Nobody wants this,” said Anna Neumann, the harbormaster at Noyo Harbor in Fort Bragg. She paid for her master’s degree in fishery policy partly by fishing off the back of a Dungeness crab boat, and has thought a lot about why whales are getting caught in the lines. “As the whales are moving in shore or they’re moving around, especially when the seasons are getting opened later and later due to the domoic acid (a marine toxin that occurs in algae which is eaten by shellfish, stays in their bodies for a certain length of time, and can be deadly to humans and other mammals), we’re seeing this increase in interactions between the whales and the fishing gear,” she said. This could be due to increased reporting, “so we simply have more eyes on the water.” Or as the population continues to increase, “With more whales, they’re more likely to come into the gear. Or it could really just be that we’re fishing more heavily.”

Crab fisheries typically experience ten-year cycles, with significant ups and downs from one year to the next, according to the CDFW. The Northern Management Area (from Point Arena near the Mendocino-Sonoma county line to Crescent City in Del Norte county), has had a good decade, with four seasons that brought in between 11.4 and 16.7 million pounds of crab. 

That’s more than the 10.1 million pounds that were brought in across the whole state this year, but the 2020-21 year was dismal, with overall statewide landings at just 3.75 million pounds. According to data provided by Christy Juhasz, an environmental scientist with the CDFW marine region, Mendocino and Humboldt counties, which include the port complexes of Fort Bragg, Eureka, and Trinidad, landed 2.8 million pounds this year. CDFW only calculates the ex-vessel value, or the price at the dock, which was $14 million this year for Mendocino and Humboldt counties, and $53.2 million statewide.

The top two fisheries in California are Dungeness crab and market squid, which is a Southern California species. That makes it difficult for Northern California fishermen to pivot to the other high-dollar fishery, says Neumann. Depending on what kind of permit they have, fishermen out of Noyo Harbor can fish salmon in California, Oregon, and Washington; hunt bottom fish drag-style, seek open-access rockfish or open-access lingcod, black cod, or various rockfish species. “So they’ll all pivot into their respective fisheries,” she concluded. But, “Even though they’re getting an opportunity to fish something doesn’t mean it’s going to necessarily be as lucrative as crab is.”

So is there a way to catch crab without leaving miles of line in the water, especially if the trend of more whales earlier in the year continues?

Ropeless gear (which actually does have ropes and buoys), is one option. In this scenario, the gear is stowed on the ocean floor next to the traps, and is either time-released or remote controlled to come to the surface when fishermen are ready to retrieve them.

But Neumann says that crews rely on the buoys to tell them where other crews’ traps are. Without the buoys, she says, fishermen could drop their gear on top of someone else’s traps, which results in the loss of expensive equipment, “ghost fishing,” or crabs dying in traps unclaimed, and lots of litter on the ocean floor.

Bartling says tests are also being done on “weak link” technology, or lines that require less pressure to break. The theory is that if a whale does get entangled, the line will give way, possibly resulting in a less severe entanglement or allowing the animal to escape altogether. Another option is “day tending,” where fishermen go out and set their pots, and then pull them in at night. “That active tending would probably help minimize the risk as well,” he said. 

“There’s other ideas that have been floated through,” said Neumann, outlining more ideas that are being tested by a Dungeness crab working group, which includes CDFW scientists and crab fishermen. “Whales are colorblind to certain colors, so they can’t see the blue ropes that we use. We all use either blue or pink lines, and even changing that line to a dark black, or a black and white stripe, has the potential to be seen by the whales in low-light situations.” 

In spite of the high number of entanglements this year and the difficulty of freeing whales from the lines, Bartling is upbeat about the health of the population at large. With data coming in from other agencies, showing increasing numbers, eating well on a variety of fish and krill, he reported, “Good news for whales, lots of good forage around, and I would expect to see more whales beginning to arrive in the next few weeks.”