TheTyee.ca
By Jude Isabella
August 23, 2011
The Salmon Doctors
It’s drizzly, cold, and muddy, and a folding table on the south bank of the Harrison River is no place to perform open-heart surgery. Tim Clark has just begun. He quickly focuses on his delicate patient, who is sucking in anesthetics through a tube down the throat. Clark stares at the body and his tongue sticks out in concentration as he leans over. The patient’s flesh is slippery, but he slices deftly into the chest cavity. In minutes, he has stitched up the wound and handed off the patient to be taken away, slightly groggy but still kicking.
Next please.
The van full of medical supplies behind Clark — gauze, forceps, gloves — is a MASH unit without a war. To the sockeye salmon resting on the operating table (a Rubbermaid container) the process must seem more like an alien abduction than surgery. Clark is no alien, though he is Australian. His purpose is to insert a data logger into the cavity behind the gills and near the fish’s heart. A tiny computer will record heart rate and temperature once the fish is released back to the Harrison River and during its final sprint to Weaver Creek, the natal stream where this population of sockeye will spawn before dying. Each surgery takes 10 to 15 minutes, depending on the fish’s sex; male salmon have thicker ventral tissue and need fewer stitches to close the opening.
Clark and the rest of the scientists arrived early this morning, in the cold mist of sunrise. Swaddled in fleece, raingear and chest waders, they set up tents, tables, scalpels and tubes, then waited for the fish. The fishers, men from the Sts’ailes (formerly Chehalis) First Nation’s fishery program, are running the beach seine to catch patients for Clark and his colleagues, and it’s high drama to watch them pull it off. They fix one end to a truck on shore, the other to a motorboat that zooms across the river and loops back to shore, snaring the catch. From dawn until about 4 p.m., they’ll deploy the seine net eight times, catching fewer salmon as the rain stops, the sun shines, the day warms, and the fish sink deeper into cooler water. The scientists have partnered with the Sts’ailes fishers for the past six years, the fishers taking DNA samples for their own fisheries program, the scientists inserting monitors. In most ways, the operations feels a lot like a traditional fish camp — except that the salmon give up their bodies for data, not food.
Knowing nothing of seining, I jumped in with everyone else to help pull in the nets full of salmon. Being on the small side, I was the weak link in the tug-of-war. The fish slapped my legs, thrashing and catching their teeth in the netting. Standing there in the midst of them gives a sense of how powerful salmon need to be to swim against the river’s current. It was easier to help Clark and a couple of graduate students make the transfer to the operating room’s waiting area, scooping salmon in hand-held nets and wading through the water to plop them into a pen. I stood in the water and wrote down tag numbers as they evaluated each fish, plucking off a scale to send to a Department of Fisheries and Oceans temporary lab at Weaver Creek.
Sockeye populations can be identified by scale patterns viewed under a microscope. Within an hour of sending the first catch, the lab, set up just for this purpose, called Clark to tell him that 11 out of the 25 were Weavers; the rest were Harrison River fish. The distinction matters. Clark studies compare fish physiology between salmon species and populations within the sockeye species. The focus of this study was Weaver sockeye, not the more plentiful Harrison sockeye. Clark pulled on his surgical gloves to start cutting.
Humans have known, through observation in the ancient past and through experimental science today, that the more salmon runs there are, the healthier the species is overall. Whatever challenges salmon face — climate change, disease, industrial pollution, overfishing, hatchery production, fish farms — they will ultimately evolve or go extinct depending on their diversity. Yet scientists are forced to prove over and over again, in deepening detail, that a species is doomed without population diversity, especially as the climate changes and water warms. The work these scientists do shows the fine, unseen, differences between sockeye populations. It should be simple. But it isn’t simple because our relationship with sockeye is overwhelmingly about money. There is nothing simple about money.
Super productive Salmon Central
The 150-metre stretch of land along the Harrison River where scientists conduct fieldwork belongs to the Sts’ailes First Nation and is called simply “The Park.” Roughly five kilometres from the Fraser River, it’s one of the most productive fish habitats in the Fraser Valley.
All five Pacific salmon (pink, chum, chinook, coho, and sockeye) species swim these waters, traditionally running from June to March. Even today, after years of commercial fishing, logging, and industrial pollution, the ecosystem erupts with life. The fish attract loads of birds. In the next couple of weeks the Park will swarm with teals and other ducks, the Sts’ailes fishers tell me, adding that over the past six or seven years cormorants have made a big splash in the area gobbling any fish that fits into their bills, including a two-pound trout. An occasional sea lion has been glimpsed trolling the Park having travelled 150 kilometres from the sea.
The riverside heart surgery is one of many in-depth sockeye studies. Fish biologists Scott Hinch and Tony Farrell at the University of British Columbia in Vancouver and Steve Cooke at Carleton University in Ottawa manage most of them. Lift the lid on their research and it’s like picking up a patio stone and seeing a colony of ants at work, all frantically moving toward individual goals that converge on a single purpose: to understand the physiology of salmon in excruciating detail. No function seems to go unnoticed, from heart rates and temperature tolerance to aging.
For the complete article :
http://thetyee.ca/News/2011/08/23/What-Makes-Salmon-Resilient/