But Is It Bird-Safe?

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...that fisheries are having on seabird populations.

Ed Melvin and Julia Parrish, two scientists at the University of Washington in Seattle, figured out some ways to help keep seabirds out of trouble.

Two families of seabirds are especially vulnerable to fishing equipment: tubenoses and alcids. Tubenoses include the majestic albatross, which can have a wingspan of over ten feet. During the breeding season, they sometimes fly thousands of miles over the open ocean in search of food, which they locate primarily [E2]by smell. Many tubenoses discovered that the fish-stinky boats of offshore longline fisheries mean lots of food. Thousands of birds will surround a single boat. They try to eat the bait off the fishing hooks. Sometimes they get caught on the hooks and drown.

Alcids are much smaller, diving seabirds. They flap furiously when flying, but are graceful swimmers underwater. They breed closer to the nearshore environment and hunt for fish by diving. They are sometimes caught in gillnets, which they can't see when they're underwater.

For tubenoses, Melvin and Parrish recommended using streamers lines, the marine version of a scarecrow, as fishing gear is being laid out. The streamers scare the birds and prevent them from getting close to the hooks before they sink. The researchers also suggested dying the bait blue. Then it disappears when it hits the water.

For alcids and gillnets, Melvin and Parrish tried something novel: they found that both fish and birds avoid white netting[E3]. When a fish sees one, it swims down; when a bird sees one, it swims up. So they put a white strip of fish netting at the top of a gillnet: the fish swim into the less visible net below, and the birds swim over it.

Melvin and Parrish's efforts have helped reduce seabird bycatch in the Alaskan fishery by eight times, and they're continuing to think of ingenious ways to keep birds out of nets and off hooks. So the next time you eat a tuna sandwich (or salmon or anchovy or, heaven forbid, squid), you can feel better knowing that many fewer birds died.

Seabirds As A Signal: What's Going On In The Pacific?

Scientists are a lot like detectives in the sense that they look at evidence and try to understand what happened. Sometimes, the evidence is really clear. Sometimes it's not. And sometimes, the evidence is thousands of birds washed up on coastal beaches.

Such was the case last year for Julia Parrish and other scientists up and down the West Coast. What followed shows how science must often work by piecing together bits of information that may not appear immediately related, but are part of a bigger pattern.

Parrish, an associate professor at the University of Washington, directs a citizen-science volunteer program called the Coastal Observation and Seabird Survey Team, or COASST. Once a month, COASST volunteers across Oregon and Washington walk a mile of beach and look for dead birds. When they find a carcass, they identify it as best they can, photograph it, and send the information back to Parrish's lab in Seattle where it's entered into a large database.

Last year, Parrish noticed that a lot of common murres and Brandt's cormorants were showing up dead on Pacific Northwest beaches. Most of them had almost no body fat and reduced muscle. They had starved to death.

It's true that seabirds have tough lives. They die all the time for a variety of reasons and it's part of the cycle of life. But when they die in large numbers, people notice. Seabirds are environmental indicators, or signals. Since they're at or near the top of most marine food webs, they're subject to whatever happens to their food sources, or their environment. As seabirds go, so goes the ocean.

Murres and cormorants weren't the only things affected, either. In California, Cassin's auklets, small birds like murres, showed signs of starvation, and were breeding later than normal. Similar tales of struggling seabirds came from British Columbia. Other scientists reported seeing emaciated gray whales.

Scientists knew that all these areas are connected by the California Current System, a large movement of ocean water from south to north. In the spring and summer, winds from the north cause upwelling along the coast, bringing up deep, cold, nutrient-rich water. The nutrients feed microscopic organisms called plankton, which in turn are the food supply of fish. The fish, from sand lance to salmon, are then food for birds.

But last year, the winds didn't come. The plankton didn't bloom. The fish that fed on plankton didn't show up in as large of numbers. And the birds and whales that depended on the fish for food starved.

Scientists don't know why the winds failed to come last year, but they have some ideas. In the meantime, they'll continue watching the ocean for clues, gathering data, and trying to solve the mystery of the seabird signal.

Making a Big Flap About It Want to know how a seabird lives its life? Look at its wings. As simple as they might seem, bird wings are marvels of engineering. Take, for instance, a common murre and a glaucous-winged gull, two of the more common seabirds in the Pacific Northwest. Both weigh about a kilogram, that is, 2.2 pounds or so. But look at their wings: the gull's are long, tapered, and slim, while the murre's are short, rounded, and wide.Two concepts explain the difference: wing-loading and aspect ratio. Wing-loading is the relationship between the area of the bird's wing and the bird's weight. Birds with high wing-loading, like the murre, have small wings relative to their weight. To fly, they need to maintain a high airspeed. Birds with low wing-loading, like the gull, don't need to go as quickly to stay aloft. The second concept, aspect ratio, is the relationship between a wing's length and its area. Long, slim wings, like the gull's, have a high aspect ratio. This increases lift and reduces drag. The gull doesn't need much thrust, but can glide. The murre's wing, being both stocky and short, has a low aspect ratio. You will never see a murre glide for any appreciable amount of time.So what kind of lives do these birds live? If you've ever seen a gull fly, they don't flap much. But a murre has to flap continuously to stay up. However, because murres are heavy and have small wings, they're good underwater divers--they're almost better at "flying" underwater than they are at flying in the air. Glaucous-winged gulls are more the wandering type, flying longer distances with relative ease, and they can't dive at all. And their wings tell you why.