Salmon Collapse Prompts Second Year of Fishing Ban

Photo: USGS

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For the second year in a row, the Pacific Fishery Management Council has canceled the California commercial salmon fishing season. The vote was Wednesday, according to Earth Justice, which blames the historic collapse of the fishery on agricultural demand for water, and federal water management policies in the Sacramento River watershed as a major factor in the decline.

In 2004, the Bush Administration set rules for use of the Sacramento-San Joaquin River Delta that allowed farms to draw more water from the system, "relaxed cold water flow requirements" and eliminated more than half of salmon spawning habitat, according to Earth Justice.

"Although federal scientists charged with reviewing the plan concluded that doing so would illegally jeopardize protected salmon, political interference by members of the Bush administration resulted in finding that project operations would not harm listed salmon and steelhead species."

While the fishery's collapse was probably not engineered in the space of just four years -- other factors certainly apply -- the management of spawning river grounds is a key factor in the health of any species of fish. In this case, the water has not been managed to sustain fish, fishermen or those who might buy the fish.

In 2008, the first ever ban on salmon fishing cost California about $255 million and more than 2,000 jobs, according to one estimate.

Worse for chinook salmon, a study by University of California-Santa Cruz scientists published a year ago in the Canadian Journal of Fisheries and Aquatic Sciences, found that just one in 10 chinook salmon spawning in California rivers are actually wild salmon. The other 90% were raised in hatcheries.

In other words, the fish humans have added to the water have propped up the population, at the same time they have masked the true decimation of the wild resource. The numbers from the study reflect the makeup of the chinook salmon in the Sacramento River in 2002, a year when about 775,000 fish spawned there. In 2008, fewer than 60,000 were expected, meaning that – if the new science is valid – just 6,000 wild fish remained in the river that enjoys the West Coast's largest salmon run.

The collapse of the salmon run will affect prices primarily on the West Coast. Most customers elsewhere in the country buy wild chinook salmon caught in Alaska, where fish are more abundant.

Here's how the university described the research:

The researchers were able to distinguish between wild and hatchery-raised fish by analyzing the banding patterns in fish ear bones, called otoliths. Like tree rings, characteristic light and dark bands in the otoliths reflect daily growth increments, and the width of the bands indicates growth rates. The differences observed between otoliths from wild and hatchery-raised fish are the result of differences in the availability of food at a critical transition in the salmon life cycle, when the young fish (called fry) have used up the food supply in their yolk sacs and must start feeding themselves. ...

"In the wild, they hide in the gravel until they use up the yolk sac, and then there is a period of slower growth while they learn to feed on aquatic insects. This abrupt transition and slow growth are captured in the growth bands of the otolith," said Rachel Barnett-Johnson, a fisheries biologist with the university's Institute of Marine Sciences. "In the hatchery, there is an abundant supply of food, so the transition is smoother and growth bands are wider."

Every fish, therefore, carries an identifier of its origin as a natural tag in the earbone, which has significant advantages over techniques for tagging fish, she said. Coded wire tags (CWTs), for example, have been used to mark fish for some studies. But only a small fraction of hatchery fish and even fewer wild fish are tagged or marked in California, according to Barnett-Johnson. Some small hatchery operations clip the fins of all hatchery fish so they can be distinguished from wild fish, but fall-run chinook salmon are not marked that way. As a result, there have not been good estimates of the proportion of wild fish in the population until this study, she said.

"The only other estimates out there pointed in the other direction -- significantly more wild fish than hatchery fish," Barnett-Johnson said. "One study used CWT recoveries from hatchery fish and estimated that 33 percent of adults returning to rivers in the Central Valley were from hatcheries. The other number floating around comes from counting the number of fish returning to spawn in rivers versus returning to hatcheries, and this estimated the number of 'wild' fish to be 3.5 times higher than hatchery returns."

One reason these figures are so important is that they could affect the listing of the fall run under the Endangered Species Act (ESA). The question of whether hatcheries can help restore threatened and endangered salmon populations or if they actually harm wild populations has long been a controversial issue. It became a legal issue in 2001, when a federal judge revoked the ESA listing of Oregon coast coho salmon, ruling that the National Marine Fisheries Service (NMFS) should have included hatchery fish in the population counts.

A more recent federal court ruling, however, concluded that the health and viability of natural populations should be used as the benchmark for ESA status determinations. That ruling has been appealed to the U.S. Court of Appeals for the Ninth Circuit.

"The agency's policy on counting hatchery fish has flip-flopped as a result of these different legal decisions," Grimes said. "Now the focus is again on wild fish, and it doesn't appear there are many of them. That could be bad news for fishing because, if the fall run is listed under the Endangered Species Act, there would be no legal harvest."

Fisheries experts blame unfavorable ocean conditions for the dismally low returns of chinook and coho salmon to rivers and streams all along the West Coast this year. In 2005, when this year's returning salmon were juveniles just entering the ocean, food production in the California Current was much lower than usual due to a delay in the wind-driven upwelling of nutrient-rich water that sustains the food web along the coast. A similar disruption of the normal upwelling occurred the following year.

"We expect the returns to be as bad or worse next year as they were this year," Grimes said. "The years when those fish outmigrated into the ocean were the worst conditions that we've seen in over 25 years of observing spring conditions."

Compounding the situation is the degradation of the freshwater habitat for salmon in the Sacramento River and the rest of the Central Valley drainage system, he said. "There is no question that the river basin's capacity to produce salmon -- the quality of the habitat -- has been degraded something awful, and it just doesn't produce like it used to," Grimes said. "We have these remnant populations -- that's all it is really. We're trying to manage what's left."

Barnett-Johnson said the otolith technique offers a new tool for monitoring the effectiveness of restoration efforts and tracking the numbers of wild fish over time. By estimating the numbers of hatchery and wild fish independently, the technique can help to differentiate between effects on the population due to ocean conditions and those due to freshwater conditions. That's because hatchery-raised fish don't face the same hazards in the initial freshwater phase of their life cycle that wild fish do, so they would be affected less by freshwater conditions. Not only are hatchery fish protected and artificially fed in the hatcheries, they also get a free ride downstream in tanker trucks. The hazards associated with migrating downstream to the ocean range from predators to the pumps that siphon water out of the rivers for human use.

"Most of the hatcheries in the Central Valley put the fish in tanker trucks and release them into the lower San Francisco Bay Delta, so they bypass a lot of the mortality that occurs in the rivers," Barnett-Johnson said. "If freshwater mortality was a key factor in population declines, we would expect to see hatchery and wild populations responding differently."

Barnett-Johnson plans to use the otolith technique to track changes in the composition of the salmon population over time. Unfortunately, because her research depends on a collaboration with commercial fishermen, the possible closure of the fishery this year may mean that she will not be able to get any salmon otoliths to analyze.

"At a time when we really need more information on the status of wild populations, a complete closure would mean I can't conduct my research to provide this estimate," she said.

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