The Rise of Competing Fish

The popular vision of the Columbia River is one devoid of fish, for the media does not focus on fish besides salmon. The author of one of the many books on the Columbia River wrote, with apparent surprise, that “standing by the fish ladder at Ice Harbor, the first dam on the Snake River, I see fish everywhere. There are large carp and schools of shad, neither native to the river, but only a few chinook, no sockeye, and only a scattering of steelhead.”23

I had the same experience when I first visited Bonneville Dam. The first thing I noticed in the charts in the fish counting room was that populations of shad had gone up ten-fold as the salmon populations dwindled.

Figure 5: Rising Shad Populations in the Columbia River Basin (in thousands)24
The real number of shad in the Columbia River is even higher than the numbers in this chart, according to biologist John Paul Mazzano, because these population estimates are “minimum numbers” made with dam counts, and large numbers of shad spawn before they get to the first dam.

At the turn of the century, shad roe was a delicacy favored by eastern gourmets. It still sells for several dollars a pound. Fishery managers thought it would be a good idea to transplant shad to the West Coast, never stopping to consider whether the rivers were big enough for both shad and salmon. Looking at the chart of shad abundance, it appears that shad were heavily overfished for many years, with harvests approaching the total run sizes. Later, fishermen (and/or the fish-consuming public) lost interest in shad and populations began to skyrocket.

One scientist has compared the increase in shad populations and decrease in salmon populations from a "biomass" perspective.

“If the average American shad adult weighed four pounds in 1990, the Columbia River production was about 16 million pounds. Together with 1990 salmonid production, the Columbia River production was about 36 million pounds. This compares to a historical high production estimate of 50 million pounds of salmonids before gross habitat losses. There is strong inference for food competition between shad and juvenile salmonids in the Columbia River and estuary today."25

From an ecological perspective, the Columbia River Basin has only finite energy resources to support fish and other aquatic life. Like a giant fish bowl, it can only hold so many fish. “When you add up the biomass from the shad population,” says oceanographer Curt Ebbesmeyer, “the Columbia is producing as much fish as it did when it was full of salmon”.26

Many people have a hard time understanding how shad could compete with salmon, envisioning competition as two creatures actually fighting with each other. When resources are limited, competition takes more subtle forms. On the Galapagos Islands, the finches are “locked in the most deadly competition even when they feed together in flocks”, for “their lives depend on how efficiently they can forage for food—how little energy they can expend in getting how much energy in return”.27

And one species can easily displace another. Some of the islands in the Galapagos have no bees, and are populated by smaller, nectar-drinking finches. But the islands that have bees, the bees have apparently displaced these smaller finches. “We never see them fight over a flower, but there is no peace between the birds and the bees.”28 No fishery manager has ever even attempted to estimate the extent to which shad have displaced salmon.

Charles Darwin regarded it as “deeply-seated error” to consider “the physical conditions of a country as the most important for its inhabitants; whereas it cannot, I think, be disputed that the nature of the other inhabitants, with which each has to compete, is at least as important, and generally a far more important element of success”.29 This “deeply-seated error” is precisely the prevailing orthodoxy among fishery managers. They focus on the physical conditions in the river, and ignore the nature of the other inhabitants. For all we know, the introduction of shad permanently capped salmon production in the Columbia River Basin.

The negative influence of the shad population is not limited simply to competition for food. There are so many shad in the river that

"Shad also are interfering with juvenile and adult salmonid passage at Columbia River projects. Basham et al. (1982, 1983) found that juvenile shad created passage problems for subyearling chinook salmon at the McNary Dam juvenile bypass system and caused mortalities. Chapman et al. (1991) reported that adult shad reduce orifice passage efficiency and fish guiding device efficiency at Columbia River projects. USACE (1982) reported that upstream migrating adult shad caused an avoidance and delay for upstream migrating adult salmon at dam fish ladders. Shad numbers have risen dramatically since then. Adult shad migrate upstream from May to August, the same season as adult sockeye and summer chinook salmon."30

Of course, if salmon are prevented from ascending the ladders, they cannot get upstream to spawn, putting further downward pressure on salmon populations.

The fact that shad populations have skyrocketed in recent years, notwithstanding the presence of the dams, provides some evidence that dams are not the limiting factor in Columbia Basin salmon production.31 As Dr. Gerald Bouck points out, “[s]had ‘smolts’ migrate downstream in the fall when there is little if any spill and . . . flows are at their lowest levels. Both salmon and shad smolts pass downstream via repeated passages through turbines, but shad travel under far worse conditions than salmon smolts.”32

Indeed, “[s]had are considered to be more fragile than salmon, and go into cardiovascular collapse, often dying from ‘shock’ if handled”.33 There is every reason to believe that the adverse effects of passing through turbines at the dams would be substantially greater on shad. Why shad thrive notwithstanding negative effects of dams is not a subject that fishery agencies choose to investigate.

Other scientists, like Dr. Wes Ebel, point out that shad produce anywhere from 20,000 to 150,000 eggs per adult female, whereas chinook produce at most perhaps 5,000 eggs per adult female. Thus shad could suffer larger losses from dams and still maintain population levels. On the other hand, shad are pelagic spawners and have lower egg survival independent of any dam-related effects. It is also possible that the dams that have created conditions conducive to shad production—although this theory seems inconsistent with shad problems caused by eastern dams.

Slowly but surely, people are beginning again to exploit the shad runs, although the shad are a bony fish chiefly valuable for their roe. Ironically, one of the most significant efforts to control the shad populations may be doing more harm to salmon populations than good. In 1995, the Yakama Tribe obtained permission to string nets across the top of fish ladders at The Dalles Dam to catch shad. Eventually, the Corps of Engineers pointed out that the adult salmon swimming up the fish ladders were spotting the nets and turning around and going back down the ladders. But the fishery managers weighed in and required the Corps to continue the program, although the nets were moved a little farther away.

By 1996, the Yakama were catching upwards of 40,000 pounds of shad a day. Their boats, however, continued to bump against the dam and cause the fish to go back down the fish ladder.34 The National Marine Fisheries Service continued to allow the harvests. Although the Service acknowledged “[t]he possibility that these effects are large, possibly resulting in degradation of a significant portion of the run (including listed fish)”, the Service is unwilling to offend the tribes by limiting the tribal fishery.35

Ironically, even other salmon species can compete with Pacific salmon. When 60,000 adult Atlantic salmon being raised in a Puget Sound fish farm escaped in 1996, they began migrating up local rivers, particularly the Elwha River. The media was quick to alarm the public with cries of “biological pollution”, reporting that “environmentalists are increasingly asking the government to treat non-native species as pollution”.36 The local Environmental Protection Agency official had advice for Pacific Northwesterners wanting to know what to do with non-native species: “It sounds a little harsh, but the best thing for the environment is to kill them.”

No one knows whether the Atlantic salmon will spawn naturally and reproduce (past escapees have failed to do so). If Atlantic salmon begin to thrive in the rivers of the Pacific Northwest, they may pose yet another competitive threat to Pacific salmon. Because they are smaller, they may have a comparative advantage in evading fishermen’s nets.

Outside the Pacific Northwest, these competing species are the subject of expensive recovery programs. Pennsylvania utilities are paying to bring back the Eastern Shad. Maine businesses shoulder the cost of trying to bring back the Atlantic salmon. Even carp are venerated, although not usually in this country. To environmentalists, suckers, catfish and carp, which do well in warm and even polluted water are creatures “of disgust” and a badge of “humilation” from environmental degradation.37

23 R. White, The Organic Machine, at 90. Mr. White attributes the rise of shad and carp to man-made changes in the River, rather than an inherent consequence of introducing exotic species.

24 From Tables 72-73, “Status Report: Columbia River Fish Runs and Fisheries, 1938-95”, at113-16 (WDFW/ODFW Aug. 1996).

25 NWPPC, Strategy for Salmon Administrative Record, P3, Vol. 11, AF3-0168 at 23.

26 Quoted in B. Rudolph, “Shad No Fad on the Columbia”, NW Fishletter, Mar. 5, 1997, at 9.

27 J. Weiner, The Beak of the Finch 63 (Vintage 1994).

28 Id. at 156.

29 C. Darwin in The Origin of Species, quoted in id. at 225-26.

30 NWPPC, Strategy for Salmon Administrative Record, P3, Vol. 11, AF3-0168 at 23.

31 G. Bouck, "Thirty years taught that money won't save salmon", The Oregonian, Oct. 20, 1995, at D7 (". . . our shad use the same dams and migration routes as salmon and have grown abundant").

32 Letter, G. Bouck to R. Baumgartner, Dec. 22, 1994, at 2.

33 Letter, G. Bouck to R. Baumgartner, Dec. 22, 1994, at 2.

34 Draft TMT Meeting Minutes, June 12, 1996, at 3.

35 See, e.g., NMFS, “Biologial Opinion on Impacts of the 1996-98 Management Agreement for upper Columbia River spring chinook, summer chinook and sockeye on listed Snake River salmon”, Feb. 16, 1996, at 9.

36 D. Westneat, “Atlantic salmon in the Elwha River: good for anglers, bad for native fish?”, The Seattle Times, Nov. 12, 1996.

37 T. Palmer, The Snake River 39.

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