Minggu, 14 Februari 2021

Innovative fishing gear is being tested to reduce impact on whales and sea turtles - The Mercury News

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A new collaborative project between environmental groups, the state, scientists, and Dungeness crab fishers is testing innovative new gear designed to reduce the impact of whales and sea turtles getting caught in fishing gear.

This is in response to California’s recent state regulations to reduce the risk of endangered whales and sea turtles getting caught in commercial Dungeness crab gear. The regulations went into effect last November, and when high numbers of humpback whales were sighted off the coast near San Francisco and Monterey Bay, the opening of the commercial Dungeness crab season was delayed by about a month.

Since 2014, the number of interactions between whales and fishing gear has been historically high. In 2019, for example, 26 whales were entangled off the West Coast, 17 of which were humpback whales.

“There’s a vertical line attached to the trap that goes to the buoys at the surface,” said Greg Wells of the National Marine Sanctuary Foundation who is managing the collaborative gear-testing research project. “That’s the part that poses an entanglement risk for whales and other marine life.”

Some of the increase in whale-fishing gear interaction is because whale populations have been recovering since the days of commercial whaling “thanks to all the wonderful conservation laws that went into place in the ’60s and ’70s to protect marine mammals,” said Jarrod Santora, an ecosystem scientist at UC Santa Cruz and the National Oceanic and Atmospheric Administration (NOAA).

But there is another factor: climate change. Marine heat waves are increasing in frequency and duration. The Pacific Ocean’s 2014-2016 extreme warming event, known as the “Blob,” is a perfect example of how marine heat waves impact the upwelling of cool, nutrient-rich water off California’s coast, compressing it inshore. This results in prey creatures like krill, sardines, and anchovies being pushed into smaller, concentrated pockets close to shore — and close to the crab fisheries.

“It’s kind of like the perfect mix to have these situations where there’s high overlap between protected species, meaning the whales, and fixed-gear fisheries” — like the Dungeness crab traps and pots — “which are typically deployed along the shelf break nearer to the coast,” said Santora.

As global ocean temperatures continue to rise, experts expect these climate events to continue. Since the whales are not going away, the fisheries need solutions for how to stay open in times of high whale activity.

This is where the new project comes in, which is a collaboration between the National Marine Sanctuary Foundation, the California Ocean Protection Council, the California Department of Fish and Wildlife (CDFW), NOAA Fisheries, West Coast Sanctuaries, and the California Dungeness Crab Fishing Gear Working Group.

There are three types of gear being tested in this inaugural round of the project. The first is called an on-demand acoustic release system. These are designed so a fisher can ping an acoustic signal, like sonar, at the pot that triggers a mesh bag to open up. Inside the mesh bag is a coil of rope attached to a buoy, which then floats to the surface, allowing the fisher to collect the trap.

The second type of gear is a timed-release buoy with a coil of metal called a galvanic release that corrodes at a constant rate. The metal starts corroding as soon as it hits the saltwater. Using that corrosion rate, fishers can calculate when the buoy will pop back up to the surface so they can retrieve it. “It’s not on-demand like the other systems and it’s not as precise, but it is a lower-cost alternative,” Wells said.

“The on-demand pop-up system would remove or negate the need of having that fixed line in the water column,” said Wells, which is the main reason why whales and sea turtles get entangled. The timed-release system would provide a similar benefit. These systems are often called “ropeless gear” because the rope spends less time extending throughout the water.

The third system isn’t an innovation but rather a gear modification. It involves a rope with periodic weak points that would break away when tugged. “If a whale, for example, was entangled,” Wells described, the weak points “would allow the whale to break free from some of that rope and the trap and the buoy.”

While this new gear sounds promising, some crab fishers themselves are skeptical of the pop-up systems.

“The ropeless gear idea is not a possible solution at all,” said Tim Obert, a captain of two crabbing boats in Halfmoon Bay who’s fishing his 21st season. Obert isn’t on the Dungeness Crab Working Group but he works closely with the fishers who are.

One reason is the high cost. With an average cost of $2,000 per crab pot for some ropeless systems and 400 crab traps on his larger boat, Obert estimates that it could cost him $800,000 to switch over to that system. That’s compared to the average price of $250 per conventional crab trap and buoy.

The other reason he cited is the failure rate of the release systems, which means lost gear and a cluttered seafloor.

Obert added that it’s important for crabbers to be able to see buoys floating on the surface so they know not to set their traps on top of someone else’s.

“My thoughts on it is that it’s good to explore ideas of gear changes and different solutions,” Obert said. But since whale populations are increasing, he feels like interacting with them is becoming inevitable. “We need better science and better data to figure out how to coexist.

“We have to fish sustainably and as safe as we can and use the best gear practices we can. We try as fishermen to be the best we can for the ocean and to paint the best picture for ourselves as we can. The last thing we want to do is interact (negatively) with any sea life.”

To that end, this new collaborative project is bringing together the fishing community, fishery managers, scientists, and environmental groups to test out proposed solutions. “In this stage, it’s really focused on reliability and retrievability” of the gear, said Ryan Bartling, an environmental scientist at CDFW who’s involved with this project. “The technology has been coming online so now we’re looking at whether they’ll be suitable replacements for the current mode of fishing.”

With no money currently earmarked in California’s state budget for reimbursing costs of the new gear, fishers will have to bear the expense, Bartling said. In this early stage, it’s important to actually test the gear before any new rules are implemented.

“The most exciting thing (about the collaboration) is working with the fishermen themselves,” Bartling said. “The manufacturers are technology experts, but in the real world of testing, the fishermen are the experts. Putting those two folks together to get them on the water to see what’s actually functional and operational — that’s exciting. The commercial crab fishery, in general, has really stepped up to this challenge of minimizing entanglement risk and this is just more evidence of that fact.”

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February 14, 2021 at 10:15PM
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Innovative fishing gear is being tested to reduce impact on whales and sea turtles - The Mercury News

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