Nav: Home

New study: How to save a seabird

February 20, 2019

In the 1990s, the endangered status of the short-tailed albatross catalyzed efforts to reduce the number of birds accidentally killed as bycatch in Alaska, home to the country's biggest fisheries. Marine fisheries scientist Ed Melvin, at Washington Sea Grant at the University of Washington, and research associate Kim Dietrich, an independent contractor, were at the forefront of a collaborative research effort that led to Alaska's longline fisheries adopting streamer lines in 2002, a technology that is towed behind vessels to create a visual barrier that keeps seabirds away from the baited hooks below.

In a new study published Jan. 28 in the journal Conservation Biology, Melvin, Dietrich and partners from Oregon State University and the Alaska Fisheries Science Center show that in the time since they were adopted, streamer lines have had an extraordinary impact: seabird bycatch in Alaska's longline fisheries has been reduced by 77 to 90 percent, saving thousands of birds per year including hundreds of albatrosses.

Melvin said much of this success is thanks to the fishing industry's active involvement when the team was researching methods to avoid seabird bycatch two decades ago.

"It's really to the industry's credit that they were fully engaged in the research and started implementing streamer lines two to three years before they became mandatory," Melvin said. "The fishermen owned the solution from start to finish."

The solution also involved training fisheries observers to properly identify seabirds in order to record vessel bycatch. "The data they were able to collect over decades allowed us to monitor and estimate bycatch rates and track the success of this effort," said co-author Shannon Fitzgerald, a fisheries scientist at the Alaska Fisheries Science Center.

The researchers arrived at their results by analyzing 23 years' worth of this meticulously collected fisheries observer data. While they found that bycatch rates remain much lower than the pre-streamer line days, more recently the number of birds hooked has been increasing.

"We have seen a continued increase in seabird bycatch, especially albatross, in Alaskan longline fisheries, with one of the recent years after our study the highest since 2002," said co-author Rob Suryan, a wildlife specialist at Oregon State University and research ecologist with the Alaska Fisheries Science Center.

In parsing out this trend, the researchers realized that bycatch significantly varied by both fishery and type of bird. The three species of highest conservation concern - the albatrosses - were more likely to be snared by a sablefish or halibut vessel than one that fishes cod. Other bird species, however, were more likely to be hooked by boats that fish for turbot, a type of flatfish.

The researchers looked into the success of other methods of bycatch reduction as well. Fishing at night, when many seabirds are less active, is a tactic commonly used elsewhere in the world. They found that fishing at night dramatically decreased bycatch rates of albatrosses while increasing the fish catch rates of Alaska's longline fleets - however, it also increased the accidental capture of northern fulmars by 40 percent.

While northern fulmars are not a species of conservation concern, the possibility of accidentally catching more of these seabirds certainly presents an unwelcome tradeoff. Melvin added that many fisheries operate in the summer, when Alaska's high latitude makes for very short nights; requiring night fishing could hurt the industry by substantially cutting down on the available fishing time.

Importantly, the scientists found that in recent years fewer than 2 percent of the 300 vessels they analyzed accounted for 46 to 78 percent of the bycatch. The authors said it is not clear why these particular boats caught so many birds. Perhaps they encountered unusually aggressive birds that were unable to locate natural prey, or perhaps they represent a newer generation of fishermen who do not feel the same urgency around seabird conservation because they were not working when the issue was first raised.

Whatever the reason, it suggests it's possible that resource managers don't need to rethink their entire seabird bycatch strategy. Targeting the few vessels with anomalously high bycatch rates with outreach about the proper use of streamer lines could prove to be enough.
-end-
This study was funded by The David and Lucile Packard Foundation and the National Fish and Wildlife Foundation.

For more information, contact Melvin at edmelvin@uw.edu or 206-543-9968.

University of Washington

Related Birds Articles:

Birds become immune to influenza
An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.
Even non-migratory birds use a magnetic compass
Not only migratory birds use a built-in magnetic compass to navigate correctly.
When birds of a feather poop together
Algal blooms deplete oxygen in lakes, produce toxins, and end up killing aquatic life in the lake.
Birds of a feather mob together
Dive bombing a much larger bird isn't just a courageous act by often smaller bird species to keep predators at bay.
Monitoring birds by drone
Forget delivering packages or taking aerial photographs -- drones can even count small birds!
The color of birds
New research provides insight into plumage evolution.
Migrating birds speed up in spring
It turns out being the early bird really does have its advantages.
Birds on top of the world, with nowhere to go
Climate change could make much of the Arctic unsuitable for millions of migratory birds that travel north to breed each year, according to a new international study published today in Global Change Biology.
City birds again prove to be angrier than rural birds
The researchers' observations shed light on the effects of human population expansion on wildlife.
Teaching drones about the birds and the bees
Unmanned Aerial Vehicles (UAVs) of the future will be able to visually coordinate their flight and navigation just like birds and flying insects do, without needing human input, radar or even GPS satellite navigation.

Related Birds Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".