Learning How to Fish Selectively

The 1998 salmon fishery gave countless examples of ways to conduct safer fisheries, using conventional and alternative fishing technologies.

by David Lane, T . Buck Suzuki Environmental Foundation fisheries researcher

This summer saw the largest experiment in BC history in selective salmon fishing. Literally, the entire coast became a selective fishing zone to protect threatened coho salmon in the North Thompson River and upper Skeena River.

As an "almost zero" coho mortality strategy, the measures were an astounding success. Instead of a coho catch averaging 2.2 million on the South Coast in the early 1990s, for example, coho mortalities from commercial fishing were zero this year in areas declared as coho "red zones" by DFO. Commercial fishing was simply closed during times of upper Thompson and Skeena coho migration.

Ultimately, there are two successful ways to eliminate mortalities of weak salmon runs: the first is to avoid catching weak stocks (close fishing at times and in specific areas where bycatch is a problem); the second is to catch and live-release weak stocks using fishing methods that cause little or no injury upon being caught and little or no injury while the fish is sorted, handled and released.

Fortunately, the experience of the 1998 salmon fishery gave countless examples of ways to conduct safer commercial fisheries, using conventional and alternative fishing technologies.

At a well-attended meeting on selective fishing in early November sponsored by commercial fishing industry groups, DFO and Fisheries Renewal, this season's strategies and experiments were reviewed and assessed. Workshops looked at how to avoid weak stocks, modifications to conventional commercial fishing gear, and alternative gear types such as fish traps, fish wheels, weirs and beach seines.

Avoiding Coho Bycatch

"Mixed stock" fishing refers to the practice of fishing at times and in areas where several species of salmon are migrating simultaneously. This is a problem if any one of the migrating species come from a threatened population.

The notion of "mixed stock" fisheries is often confused with open-ocean vs. river mouth fisheries. It is often assumed that if you move fisheries to river mouths you eliminate the mixed stock problem. Not so. The fisheries in the Skeena River and Fraser River are mixed stock fisheries facing significant problems with weak runs of coho, steelhead and chinook. Conversely, in some areas of the coast at some times of the summer, only Fraser River sockeye are migrating, allowing conventional fishing gear to be entirely selective.

The main strategy for conventional commercial fishing gear, therefore, is to close specific areas to fishing by seines, trollers and gillnets at times that threatened runs are migrating.

All gear types and all areas faced drastically reduced days for fishing in 1998. Because of the area licensing scheme brought in by former fisheries minister Fred Mifflin, some area-based fish boats had almost no opportunity to fish. Particularly hard hit were West Coast trollers and Skeena River gillnetters.

These fishing restrictions, however, produced highly selective fishing. Of 3.4 million salmon caught in the commercial fishery on the South Coast, for example, coho mortalities were only 0.006 percent of the total catch. Although gillnets have the poorest survival record for live-releasing coho, they had the lowest coho mortalities of all traditional gear because they were better at avoiding catching coho. Fraser River gillnetters had the lowest coho mortalities because the fishery was simply closed before the coho enter the river at the end of August. Seine boats had the best record on successful live release, but they also caught the most coho, resulting in the highest number of mortalities for traditional gear on the South Coast.

Salmon Eggs Sensitive To Very Low Levels Of Oil Pollution

Recent research from the aftermath of the Exxon Valdez oil spill in Alaska dramatically injects pollution issues into the debate about the decline in salmon stocks. Four years after the spill, Alaska Department of Fish and Game biologists recorded elevated mortalities among pink salmon embryos incubating in the contaminated sections of affected streams. This was unexpected because stream bed contamination was thought to be minimal, and salmon eggs were not considered sensitive to polynuclear aromatic hydrocarbons (PAH).

Subsequent research by the US National Marine Fisheries Service incubated pink salmon eggs in gravel contaminated with known quantities of oil. After three brood years, the researchers concluded that pink salmon eggs are sensitive to low concentration of the PAH that characterize weathered oil and that effects can be observed in eggs incubating downstream from the oil source. Embryos exposed to PAH concentrations of 1 ppb showed a twofold increase in mortality and a 10% reduction in growth during their first 6 months in saltwater.

The scientists estimate that exposed eggs in Prince William Sound produced 38% and 42% fewer mature adults than unexposed eggs in the 1993 and 1995 broods, respectively. The very low levels of oil pollution which affected the fish were present in Prince William Sound for four years after the spill.

Routine oil spill on roadways, which washes into streams and the ocean, far exceeds the amount of oil spilt in tanker accidents.

* Pink Salmon Demonstrate Acute and Long-Term Effects After Exposure to Very Low Concentrations of Polynuclear Aromatic Hydrocarbons (PAH) During Incubation, R.A. Heintz, National Marine Fisheries Service, Auke Bay Laboratory, Juneau, AK, presented at the 1998 meeting of the American Fisheries Society Division, Anchorage, October 1998.

Modifications To Conventional Gear

Experimental modifications were tested on all three traditional commercial fishing gears this season in a program initiated by a committee of representatives from various commercial fishing organizations. An extensive coho mortality study was conducted in Barclay Sound — on a healthy hatchery coho run — to see how effective these modifications were at reducing bycatch mortalities. All fish live released in this experiment were tagged and kept in a holding area for three days, then tagged fish were identified on the spawning grounds.

Seine boats were tested to compare the effect of wet brailing techniques. Instead of pulling the seine net up the stern of the boat, which can sometimes injure or crush fish, salmon were scooped out of the net while it was still in the water, using a brailer (a large dipnet) that keeps the fish in water with a funnel hole at the bottom. If done carefully, salmon can be kept in water during almost all of the brailing and sorting, and coho can be live-released with mortalities as low as 2 percent, far below standard 25 percent mortality typically attributed to seining. Trollers tested coho recovery tanks compared to releasing coho from the hook at the waterline before any handling in the boat. Gillnetters tested out the benefits of leaving nets in the water only 30 minutes, so more survive unharmed. They also tested various "hang ratios" on the nets, which varies the looseness of the net and the degree to which fish get tangled.

Live-release mortalities for all three gear types were improved over previous mortality estimates, but the single biggest factor in safe live release seemed to be the careful, slower handling of the fish by fishers with experience in these techniques.

Alternative Gear

For several years now, some alternatives to the traditional fishing gears have been tested, mostly by First Nation communities in river conditions. Not all of these have involved selecting out weak stocks. Handling of fish can cause some scaling and some mortalities, but these are minimal.

The most successful of these to date is the First Nation fish wheel program on the Nass River. A fish wheel looks somewhat like the stern of an old paddlewheel boat, if you think of the paddles being replaced by mesh baskets that scoop fish out of the water into a holding tank. The fish wheel is fixed to a site and the flow of the river turns the wheel. Four fish wheels, costing about $25,000 each, are used for stock assessment, food fishing and for commercial sale. Wheels are also being tested on the Skeena River and the Fraser River at Yale. The high capital cost and the high labour cost required for continuous monitoring make these ventures currently more useful for stock assessment contracts with DFO and for food fishing needs. Proper placement of a wheel is critical, as sites must have adequate water flow to turn the wheel, and must be in currents relatively free of wood debris floating downstream. The Nass and Yale wheels are not currently operating as selective fisheries, although both First Nations are planning future release experiments.

A fish trap has been operated for several years by the T'Sou-ke First Nation, south of Sooke. They are improving their techniques with help from East Coast cod trap fishers. The T'Sou-ke trap has not been able to fish large numbers and has been plagued by seals and sea lions looking for an easy meal. They are the only group other than salmon farmers to have a legal permit to shoot seals.

A mobile fish trap experiment took place on the Skeena this year operated by gillnet boats. Fish traps have been used for many years in Alaska, but have become uneconomical with the low price for pink and chum salmon. The Skeena trap operation was conducted by three boats with a trap costing about $17,000. It needs a large area of river to operate in, making it difficult for many boats to participate in such a fishery, but it showed some promise of producing high quality salmon for niche markets. If a lot of boats were using such technologies, the niche markets could easily be flooded, dropping the price to below that needed to make a reasonable income.

Weirs and dipnets, traditional First Nation fishing methods, continue to be used in upriver locations on the Fraser and some other systems. The Shushwap First Nation uses weirs for stock assessment, and other First Nations collect salmon for food purposes.

Beach seines have been tried on the Skeena, the Fraser and the Nimpkish. Of these, only the Skeena First Nation beach seines caught enough to be profitable. In the Fraser chum fishery test, a jet boat hauls the net which is tied up on shore. The net is brought in tight to the beach and non-target salmon species are live-released with a dipnet. Wood debris floating downstream into the net is a constant problem, as are snags on the bottom. It is a very labour intensive method of fishing and has so far not proven successful as a viable option for commercial fishing given the costs (a seine net can cost $14,000 and a used boat is $30,000) and the low price for chum salmon. The Nimpkish beach seine does not involve live release selective fishing, but the location of the beach seine strongly favours sockeye over other species.

Problems Persist

In general, problems persist in developing alternative selective harvesting methods. Capital costs are often high. Most methods have difficulty catching large quantities of fish, and labour costs are high to protect gear from debris and to adequately handle live-release. Few experiments to date could catch enough fish to cover expenses.

Beyond these problems, the issue of access to fisheries will persist. New upriver alternative gear fisheries remain closed to non-First Nation commercial fishers and to aboriginal commercial fishers in coastal communities. And new commercial gear that is not suitable to be accessed by most existing commercial fishers will continue to create the impression that some individual fishers are out for a "fish grab." Federal commercial fish license policy and area licensing are actually acting as a deterrent to some sections of the commercial fishing community moving to more selective fishing because they legally box fishers into using rigidly-defined fishing gear.

Finally, we must also look at better ways for the sports fishery to become more selective. Many think of sports fishing as having a relatively minor impact, but it should be remembered that this season the recreational fishery on the South Coast caught almost four times as much coho as the commercial fishery.

These issues must be resolved while we all search for a new vision of a fishery based on conservation, a fishery that includes all fishers with a long-term interest in preserving healthy, biodiverse salmon runs coast wide for future generations.


[From WS December 1998/January 1999]

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