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PORT OF FRIDAY, Washington. – At present, the millions of people around the world who have followed the saga of a mother orca carrying her dead calf know that orca whales living in the south of the country eat only chinook salmon. But what does chinook eat?
A team of researchers climbed into a small submarine and plunged to the bottom of the Salish Sea off San Juan Island last week in search of forage fish that is the staple of chinook.
They were looking for sandeel, a groundfish rich in fat and protein. Scientists know very little about its life and habitat in the Salish Sea. But they know that it is an essential link in the food chain.
"If this forage fish disappears, the salmon will disappear," said Gary Greene, a marine geologist who works with the non-profit company SeaDoc. "We are just beginning to master these things now."
Scientists had the rare opportunity to see sand lance habitat through the porthole of the small submarine, built by OceanGate, based in Everett. The submersible has a bulbous window on the front and can seat five people and dive about 500 meters, or 1,640 feet – one and a half times higher than the Columbia Center, Seattle's tallest building.
Scientists want to develop a knowledge base on sand eel to see if its habitat changes. A concern: the rise in sea level, which will affect the currents, could sweep away the sandy sediment in which the sand eel lives.
The submarine "was a very good observatory," said Greene after his first dive into the ship.
SeaDoc, an 18-year-old non-profit organization based in the island of Orcas, is working to understand the environmental factors that can affect the health of the inland sea.
"Our role is to bring together the scientific knowledge needed to make decisions about how to take better care of this place," said Joe Gaydos, Scientific Director of SeaDoc. "We saw a clear need for offshore research that was not occurring" because of the cost and logistics of underwater exploration, he said. SeaDoc used private funding to partner with the OceanGate Foundation to make the submarine available.
Greene, a researcher at Moss Landing Marine Labs in California, now living in San Juans, is an expert in underwater surveying and has mapped the entire bottom of the Salish Sea. On September 11, he plunged into the submarine with Matt Baker, a marine biologist and sand expert. The two scientists are working in Friday Harbor Labs at the University of Washington.
Greene said he and Baker were surprised to see much more sand lance than expected. The fish emerged from the sand as the submarine approached, a startling sight that suggested how the chinook might be able to hunt them.
The sand spear is so fat that if you dry it, it will burn, said Greene. There is no swim bladder to stabilize it in the water column, which is unusual in fish. To rest, escape from predators and overwinter during the cold months, the slender fish uses its pointed muzzle to dive headlong into moving "waves" of sand hundreds of feet below the surface.
He dines on tiny organisms like copepods and zooplankton, transferring energy from organisms at the bottom of the food chain to animals at the top, such as killer whales.
Submarine scientists also examined whether scientific trawling on the seabed caused environmental damage (so far, it appears that this is not the case). They also looked closely at the red sea urchins that live in Haro Strait, the deep channel west of Lime Kiln Point National Park on San Juan Island, where killer whales hunt salmon – and where J50, a resident of J pod, was last seen alive.
Here, on the edge of the island, the bottom falls precipitously. It is an ideal habitat for red sea urchins, which can live up to 150 years. They move so little that they "look a bit like an old-growth forest," said Alex Lowe, a postgraduate student in biology.
On a recent dive, Lowe and Aaron Galloway, an assistant professor at the Institute of Marine Biology at the University of Oregon, spotted a red sea urchin at about 284 meters, more than double the known range of sea urchins.
Sea urchins feast on a treadmill of kelp salad – leaves that have broken kelp plants. "This broadens our perspective on what this particular species does," said Galloway.
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