1. A Predation Plan should be an integrated overview of predation
issues; one Plan would be better than three
2. One Predation Plan must include predatory native fish
3. A Predation Plan needs to focus on the goal of restoring
wild native salmonids as outlined in the OCSRI and by the
federal government
4. A Predation Plan needs to recognize that hatchery fish attract
predators; examples include:
Columbia River
Yaquina and Coos Bays
Conclusion
5. A Predation Plan needs to disclose reasons why hatchery fish
are extremely vulnerable to predation
6. A Predation Plan should mention that hatchery fish may
increase predation on wild fish and have other negative
effects on wild fish
7. A Predation Plan has a greater chance of success if it is based
on a geographical area, rather than each species of predator
Columbia Basin Predation Plan
Predation Plans for Other Coastal Streams
8. A Predation Plan should include the option of reducing
predation by decreasing the number of hatchery fish,
which could increase their survival and benefit wild fish
Pinniped Predation Action Plan
Introduced (Exotic) Fish Predation Action Plan
Avian Predation Action Plan
Literature Cited
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General Comment 1. A Predation Plan should be an integrated overview of predation issues; one Plan would be better than three.
After reading these Plans, it appears that they have not been coordinated and that they have been written on a species by species basis without a perspective of viewing predation issues as a whole. Further, several significant predators have not been included. If predation is to be reduced, a broader, more objective perspective of predation must be attained.
Hopefully, the authors of the revised plans will work together to find common ground about predation issues rather than be isolated in their own particular area of expertise. One way to encourage this would be to have a single Plan for all predators and to have the Plan divided by basins rather than for species (see my Comment 7).
General Comment 2. One Predation Plan must include predatory native fish.
In a 1997 budget note to the ODFW Fish Division by the Natural Resources Subcommittee in Oregon Senate Bill 5503 (see http://www.leg.state.or.us), the Legislature directed the ODFW to compile information about the predation of salmon smolts and adults by "birds, exotic fish species, and pinnipeds." With these three Action Plans, the ODFW has complied.
Unfortunately, the Legislature did not include all predators, since there is no Plan for native fish predators. Some native fish that are predators of smolts include northern squawfish (whose name has changed to the northern pike-minnow) and native salmonids. Given that northern squawfish are considered the most significant fish predator of juvenile salmonids in the Columbia (Beamesderfer and Rieman 1991, Poe et al. 1991, Rieman et al. 1991, Vigg et al. 1991) and the well-publicized $1.4 million bounty program placed on them by the Bonneville Power Administration to reduce their predation of salmonids (e.g., Monroe 1990), it is a significant oversight that they are not included in any Action Plan. The predation of smolts near the mouths of the Columbia and Yaquina and Coos Bays by subadult or adult coho (Angstrom and Reimers 1964, Fresh et al. 1981:27, Stuart and Buckman 1985), chinook (Fresh et al. 1981:17), steelhead (Fresh et al. 1981:35), and cutthroat trout (Brodeur et al. 1987:9) can also be considerable. The goal of the Plans is to reduce predation, so at least listing predator species within three miles of the Oregon coast, which is within the jurisdiction of the Oregon Fish and Wildlife Commission is relevant to these Plans.
Perhaps there is nothing that can be done to reduce the predation by native fish, but, even so, this still needs to be discussed in a Plan. Afterall, there are Plans for introduced fish and pinnipeds, although the authors seem to conclude that there is nothing that can be done to effectively reduce predation by these species.
General Comment 3. A Predation Plan needs to focus on the goal of restoring wild native salmonids as outlined in the OCSRI and by the federal government.
The goal of these plans appears muddled. On one hand, these Plans seem to be in response to Oregon Senate Bill 5503, which requires an examination of salmon predation in general. On the other hand, the cover letters to these Action Plans seem to indicate that their goal is to be in accordance with the OCSRI. If so, these Predator Action Plans appear to have lost sight of the OCSRI's goal of restoring wild, native salmonids because these Plans do not distinguish between predation of wild and hatchery salmonids and seemingly consider the reduction of predation of hatchery fish as an OCSRI goal.
The OCSRI's focus on wild, native fish is a continuation of the Oregon Fish and Wildlife Commission's decision to adopt a wild fish management policy (e.g., ODFW 1985). In addition, federal (National Marine Fisheries Service, NMFS) proposals or listings of salmonid populations in Oregon under the Endangered Species Act have thus far been for naturally spawning (wild) Umpqua coastal cutthroat (1996, 50 CFR Part 222, Federal Register [FR] 61[155]:41521), coho salmon (1997, 50 CFR Part 227, FR 62[87]:24609), steelhead (1997, 50 CFR Parts 222 and 227, FR 62[159]:43938-43939), chinook salmon (1998, 50 CFR Parts 222, 226, and 227; FR 63[45]:11483), and chum salmon (1998, 50 CFR Parts 226 and 227, FR 63[46]:11775). It is possible that the NMFS may include some hatchery populations in their listings, but only if they are essential for the recovery of natural populations (1997 FR 62:24609, 1998 FR 63:11483).
Thus, if Predator Action Plans are to be in accordance with the OCSRI and federal listings, they must keep their focus on wild, native salmonids. If these Plans have an additional goal of reducing predation on hatchery fish, then this must be clearly stated and justified because this is a separate issue.
General Comment 4. A Predation Plan needs to recognize that hatchery fish attract predators; examples include the Columbia River and Yaquina and Coos Bays.
Predation of hatchery and wild native salmonid smolts can differ significantly. If the goal is to restore wild salmonids, then measures to reduce their predation need to be specifically addressed, and if the goal is to reduce predation of hatchery salmon, then this issue must be examined separately. Pooling the predation of hatchery and wild juvenile salmonids only serves to make it less likely to find effective measures to deal with predation of either.
Unfortunately, most studies of predation have not differentiated between predation of hatchery and wild smolts, perhaps because it can be difficult to determine if a partially digested fish originated in the wild or from a hatchery, unless the fish has a Coded Wire Tag or Passive Integrated Transponder. Nevertheless, there is evidence that hatchery smolts are more vulnerable to predation than wild fish at several areas in Oregon. In the following sections, these areas are arranged from north to south.
COLUMBIA RIVER. In freshwater portions of the Columbia, northern squawfish aggregate near hatchery release sites to feed on juvenile salmon (Thompson 1959, Collis et al. 1995).
In the lower Columbia Estuary in 1996, Roby et al. (1998:47, 53-55, 73, 77) reported that Caspian terns took significantly more hatchery than wild smolts at a tern colony at Rice Island near Astoria. About 85% of the smolts available to Caspian terns were hatchery smolts, but 95% of the smolts taken by terns were from hatcheries; in contrast, about 15% of the smolts available to terns were wild, and terns took less (5%) than expected from their relative abundance (calculations from Roby et al. 1998:54 [Table 12]).
In the mouth and just offshore of the Columbia Estuary during 24 May- 11 June 1982, Matthews (1983:30, 80-84, 92) found that coho smolts were 2% of the diet of common murres, which is high, considering that Scott (1973:58) did not find any salmon smolts taken by murres near Yaquina Head in 1969-1971 and that Matthews (1983) only found coho smolts to be more than 0.1% of the diet of murres off Coos Bay when there were large number of hatchery smolts released into Coos Bay (see below).
During 1983-1987 experimental releases of hatchery coho smolts at Tongue Point (which is just east of Astoria and near the current large Caspian tern colony at Rice Island), the Columbia Bar, and three locations off the mouth of the Columbia, predatory birds were attracted at all sites, with the average of 689 birds at the Bar much greater than the average of 13-31 birds elsewhere (Solazzi et al. 1991:252).
For revised and updated comments for Yaquina and Coos Bays; see Attraction of Birds to Hatchery Releases of Juvenile Salmonids at Yaquina Bay and Coos Bay, Oregon
CONCLUSION. The few studies in Oregon about predation of juvenile hatchery salmon indicate that they attract predators in freshwater, in estuaries, and in the Pacific Ocean near estuaries, especially when hatchery fish are very numerous. This situation is not unique to Oregon; elsewhere in the Pacific Northwest, northern squawfish took more hatchery than wild smolts (Schroder and Fresh 1992:281-287), and predatory birds (Mace 1983, Wood 1987) and spiny dogfish (Beamish et al. 1992) were attracted to and consumed hatchery juvenile salmon. In British Columbia, 30% of one release of hatchery steelhead were consumed by seals (Olesiuk et al. 1990 cited in Kaczynski et al. 1993:123).
Since coho and chinook hatchery releases in the Pacific Northwest have increased greatly since 1975 and about 30% more smolts that were mostly hatchery fish were in the Columbia in 1990 and 1992 than historically (Kaczynski et al. 1993:295, Beamish et al. 1997), it is not surprising that predators have aggregated in the Columbia Estuary (Roby et al. 1998).
General Comment 5. A Predation Plan needs to disclose reasons why hatchery fish are extremely vulnerable to predation.
INTRODUCTION. As just mentioned, hatchery smolts are known to be vulnerable to predation. If the goal of a Predator Plan is to reduce predation of hatchery salmonids rather than the goal of the OCSRI or federal listings, the vulnerability of hatchery fish must be addressed squarely, which is not done in these Plans.
Hatchery salmonids do not survive as well when released as do wild salmonids (Fraser 1974, Reisenbichler and McIntyre 1977, Gunsolus 1980, Dickson and MacCrimmon 1982, Ersbak and Haase 1983, Bachman 1984, Piggins and Mills 1985). There are several reasons why hatchery fish are more vulnerable.
Hatchery fish attract predators because they are very numerous and very large. For example, an average of 0.3 million coho smolts have been released at a time (Bayer 1986:281). Further, many, if not most, hatchery coho smolts weigh 25-45 g/smolt at release (Bayer 1986:281, Lewis 1996); in contrast, wild coho smolts generally averaged 8-12 g (Moring and Lantz 1975:23-24) and are not as fat as hatchery fish (Myers 1980:32-33).
SHORT-TERM VULNERABILITY OF HATCHERY FISH: PREDATOR ATTRACTION. Recently released hatchery fish attract predators and are easy to catch because they have been stressed, disoriented, and forced into an unfamiliar environment (Macdonald et al. 1988). The stress of release can impair the ability of smolts to avoid predators or diminish their swimming abilities (e.g., Sylvester 1972, Coutant 1973, Sigismondi and Weber 1988). Smolts may also have to adjust to salt water, which can make them act "sick" and impair their ability to escape predators. ODFW hatchery fish are reared in freshwater, so after they are released and move into estuaries, it may take about 100 hours for them to adapt to salt water; during this time they are physiologically stressed (Harry Wagner, ODFW Staff, oral testimony at the 20 April 1989 Work Session on House Bill 3185 before the House Committee on Agriculture, Forestry and Natural Resources).
Recently released salmonids are easily detectable to predators because some behave inappropriately in their new environment. Since hatchery salmonids are familiar only with feeding on pellets spread on the water surface, many smolts come to the surface to feed shortly after release and in so doing are easily seen by potential predators. Also, newly released smolts often jump out of the water or roll on their sides, exposing their highly conspicuous silver sides, which makes it very easy for predators to find them (Bayer 1986).
Hatchery salmonids also attract predators because they tend not to disperse after a release, so that they remain in schools near the surface where they can be easily found and eaten by predators (Vincent 1960, Fresh 1983:74). Since juvenile salmonids in hatcheries usually receive little exercise, their stamina appears to be less than for wild salmonids (e.g., L. S. Smith et al. 1983, 1985). This makes it more difficult for them to avoid predators and may impair their ability to feed and position themselves in the water column after release (Besner 1980, Besner and Smith 1983, L. S. Smith et al. 1983, 1985; Shchurov et al. 1986).
Recently released hatchery salmonids are also naive and not wary of predators (e.g., Vincent 1960, Thompson 1966, Kanayama 1968, Fraser 1974, Patten 1975, 1977; Ginetz and Larkin 1976, Olla and Davis 1989, Suboski and Templeton 1989).
LONG-TERM VULNERABILITY OF HATCHERY FISH: PREDATOR ATTRACTION. Researchers mostly have focused on the short- term vulnerability of hatchery salmonids to predators, but their long-term vulnerability is also significant. For example, hatchery fish would have been long exposed to predators and their environment by the time they reached the lower Columbia, yet Roby et al. (1998) found that Caspian terns were still selectively catching hatchery fish. Further, many hatchery coho were being caught in the ocean off Coos and Yaquina Bays (Comment 4). Perhaps, hatchery fish are vulnerable over the long term because they have been entrained in hatchery conditions to live in high-densities.
SHORT- AND LONG-TERM VULNERABILITY OF HATCHERY FISH: FEEDING INEFFICIENCY CONTRIBUTING TO PREDATION. Another reason for the long-term vulnerability of hatchery salmonids to predation is that they may not be able to feed efficiently, so that they become vulnerable to disease, parasites, and/or predation. In other words, hatchery fish may die from predation a week or more after release, but the underlying cause for this is that they are undernourished.
Since current hatchery salmonids are only familiar with eating pellets spread on a hatchery pond, it is understandable that they may have a problem shortly after release in finding natural food (e.g., Sosiak et al. 1979, Ersbak and Haase 1983, Bachman 1984, Kennedy et al. 1984, Suboski and Templeton 1989). This problem may be aggravated because hatchery fish position themselves higher in the water column than wild fish, so hatchery fish may not be located where appropriate prey are most abundant or are easiest to catch (e.g., Dickson and MacCrimmon 1982).
Some studies of salmonid smolts in aquaria have demonstrated that hatchery fish can quickly learn to catch natural prey (Paszkowski and Olla 1985, Stradmeyer and Thorpe 1987). But hatchery fish may do more poorly in the wild than these studies indicate because finding and catching sufficient prey to survive and prosper in the wild would be much more difficult than doing so in an aquarium (Stradmeyer and Thorpe 1987).
Identifying and catching prey clearly appears to be a problem for newly released chinook smolts. At Tillamook and Yaquina Bays, chinook smolts a week after release had stomachs that were much less full than those of wild smolts collected at the same time (Forsberg et al. 1975:26, Myers 1980:154). At Yaquina Bay, Myers (1980:152) also found that stomachs of recently released chinook smolts often contained extraneous material such as pine needles, seeds, wood and paint chips, and pieces of plastic and styrofoam. At Puget Sound, L. S. Smith et al. (1970) found that recently released chinook smolts had little but pieces of wood or debris in their stomachs.
Coho smolts may not have as much difficulty in adapting to natural food. At Yaquina Estuary, Myers (1980:91) found that hatchery smolts were apparently quickly feeding on natural prey, but, at Siuslaw Estuary, Nicholas et al. (1979) found that most hatchery coho smolts had empty stomachs. Studies of hatchery coho smolts in aquaria indicate that 69% can quickly identify and catch natural prey (Paszkowski and Olla 1985). But Paszkowski and Olla (1985) also found that the other 31% did not adapt and suggested that such a minority of nonadaptive smolts could contribute to the poor survival and feeding performance often reported for hatchery salmonids.
Hatchery smolts not only need to learn to identify and catch wild prey, they need to do so efficiently enough to at least maintain their body weight. Inefficient feeding has been a recognized problem for hatchery smolts (Ersbak and Haase 1983) that may be aggravated because hatchery fish may have higher energy and food demands than wild fish. For example, food requirements of recently released hatchery fish may be greater, since they are adapted to digesting food pellets and may not be able to efficiently digest natural food (Kennedy et al. 1984). Further, the basal metabolism of hatchery fish may be higher than for wild fish (Ersbak and Haase 1983), and hatchery fish may expend more energy in searching and catching prey than wild fish (e.g., Bachman 1984, Paszkowski and Olla 1985).
The length of time that it takes hatchery smolts to become as efficient in feeding as wild smolts is unclear and may differ among smolts (see Paszkowski and Olla 1985). For Atlantic salmon, some hatchery smolts took up to two months before they had the variety or amount of prey as wild smolts (Sosiak et al. 1979, Kennedy et al. 1984).
Since predators are known to take weak or impaired prey (Curio 1976), smolts that are not feeding adequately may accordingly be very vulnerable to predation, especially since hungry hatchery coho juveniles expose themselves more to predators when they are hungry (Dill and Fraser 1984).
CONCLUSION. Hatchery smolts attract predators and have been described as "candy" or "hot dogs with fins" by some fishery biologists, so it is not surprising that hatchery fish have been found to be more vulnerable to predation in Oregon. Many of the issues unique to hatchery fish predation are not relevant to the predation of wild fish and need to be treated separately.
General Comment 6. A Predation Plan should mention that hatchery fish may increase predation on wild fish and have other negative effects on wild fish.
Hatchery fish may be a significant factor in the predation of wild fish. Wild fish spread themselves out more than hatchery fish (Fresh 1983), so that they would not be as conspicuous or as available to predators. Thus, mass releases of hatchery fish could attract predators that prey on wild fish that predators would not otherwise detect.
Although not directly relevant to predation issues, it should be mentioned that hatchery fish appear to have several significant, negative effects on wild fish (e.g., Dentler and Buchanan 1986, Schaeffer 1991:12-14, Kaczynski et al. 1993:45-55). Then, it would be clearer that what benefits hatchery fish may not benefit wild fish.
General Comment 7. A Predation Plan has a greater chance of success if it is based on a geographical area, rather than each species of predator.
The focus of the DPAP's is on each predator species; this approach is unlikely to result in improving the survival of juvenile salmonids because controlling one predator may simply result in increased predation by other species (i.e., compensatory predation) in the area. Further, predation reduction measures will be implemented at specific areas; thus, tailoring a predation plan for specific areas or basins similarly to the ODFW's "Basin Fish Management Plans" (e.g., Borgerson et al. 1991) makes practical sense. Another advantage to area plans is that it would allow ODFW biologists with differing areas of expertise to cooperatively work together to try to reduce overall predation.
I do not have time to write about each area, but in the following sections I discuss predation at the Columbia and some coastal streams.
COLUMBIA RIVER BASIN PREDATION PLAN. Compared to other Oregon estuaries, the Columbia is considerably larger, has many more hatchery fish (200-300 million released yearly)(Kaczynski et al. 1993:295, Beamish et al. 1997:1211), and has more and different kinds of legal issues and federal and state governmental agencies involved because of the dams, tribal fishing rights, water rights for agriculture, and split jurisdiction between the States of Oregon and Washington. Further, the Columbia has a much greater problem with freshwater predatory fish than other coastal streams, and the Columbia is unique in having dams that stress migrating juvenile salmonids and thereby make them more vulnerable to predators. Thus, it is imperative that a Plan be prepared for all predators at the Columbia.
In freshwater portions of the Columbia, significant fish predators of juvenile salmonids include northern squawfish, channel catfish, walleye, and smallmouth bass (e.g., Thompson 1959, Beamesderfer and Rieman 1991, Poe et al. 1991, Rieman et al. 1991, Vigg et al. 1991, Tabor et al. 1993, Beamesderfer and Ward 1994, Tinus and Beamesderfer 1994, Collis et al. 1995). The Bonneville Power Administration has a $1.4 million bounty program for northern squawfish (e.g., Monroe 1990), which is not a popular game fish. However, it is unclear if any reductions in squawfish predation had any effect on overall salmon survival or if salmon that were saved from squawfish were eaten by other predators. Walleye populations appear to have doubled in recent years and may take about half as many salmonids as squawfish in some reservoirs (Tinus and Beamesderfer 1994:19), but warmwater game fishes (which includes walleye, channel catfish and smallmouth bass) in Oregon are, as p. 16 of the Introduced Fishes DPAP writes, "... extremely popular and economically important fisheries." So plans to try to reduce predation of these fish would be met with resistance from fishermen, and management plans have concluded that controlling these species would probably not have a beneficial effect on salmon survival (Beamesderfer and Ward 1994, Tinus and Beamesderfer 1994, Introduced Fishes Plan:17).
Reported freshwater bird predators of juvenile salmonids include include ring-billed and California gulls (Ruggerone 1986, Roby et al. 1998:4-5, 39-41), and their predation has been most conspicuous below dams where migrating juvenile salmonids are particularly vulnerable after passing through the turbines. Control measures have included putting up monofilament lines to exclude gulls and shooting gulls at dams (Ruggerone 1986:741, Roby et al. 1998:17, Jones et al. 1996). It is unknown if the salmon saved from these birds are all eaten by the predatory fish that are known to occur in the same areas.
Introduced American shad are not included in the Introduced Fishes Plan, but adults have been reported to have eaten as many 16 chinook smolts (Wendler 1967 cited in Kaczynski et al. 1993:120); however, this appears anomalous for migrating adult shad within the Columbia as Hammann (1982) only found one of 26 adult shad had any stomach contents, and the one that did had only small prey.
Estuarine fish predation of juvenile salmonids in the Columbia Estuary in 1980 was considered minimal as McCabe et al. (1983:820, 822) only found two instances of predation where two yearling chinook salmon each ate a subyearling chinook. However, large fish may have avoided their fishing gear, and their once monthly sampling may have missed fish predation on pulses of hatchery salmonids. New studies are needed to determine if increasing dredge spoil islands and millions of hatchery fish have increased fish predators into the Columbia Estuary.
Known bird predators in the Columbia Estuary include Caspian terns, double-crested cormorants, and glaucous-winged/western gull hybrids nesting within the Estuary (Roby et al. 1998). In 1997, terns were estimated to take 5-20 million juvenile salmonids, and cormorants and gulls might have also taken millions of smolts (Roby et al. 1998). Fish-eating birds (especially common murres) that did not nest within the Estuary were not included in Roby et al.'s (1998) study, although murres are numerous at the mouth of the Columbia (Matthews 1983:80-85) and can be significant smolt predators in other Oregon estuaries (see Comment 4). One natural control measure in place for Columbia Estuary terns is their extremely low reproductive success in 1997, even though the tern colony was the largest in North America and possibly the world (Roby et al. 1998).
Seals and sea lions prey on some adult salmon within the Columbia as well as offshore (Kaczynski et al. 1993:121-128).
In the ocean near Columbia, fish predators have not been well studied, but subadult or adult coho (Angstrom and Reimers 1964, Fresh et al. 1981:27), chinook (Fresh et al. 1981:17), steelhead (Fresh et al. 1981:35), and cutthroat trout (Brodeur et al. 1987:9) were found to have fed on juvenile salmonids. Similarly, Stuart and Buckman (1985) noted that many adult coho caught in the ocean near Yaquina and Coos Bays had consumed coho smolts, and Nickelson (1986) suggested that adult coho predation of smolts may be a major reason for reduced smolt survival. In addition, Brodeur et al. (1987:9) reported that juvenile salmon were often found in black rockfish caught by hook and line in nearshore rocky reefs along the Oregon and/or Washington coasts, Anonymous (1959) found that hake, rockfish, lingcod, sculpins, adult chinook, and cutthroat trout fed on juvenile chinook released into Hood Canal; and Beamish et al. (1992) recorded that spiny dogfish were attracted to the mouth of a British Columbia estuary, where they consumed hatchery coho and chinook smolts. In contrast, Brodeur et al. (1987:1, 9) did not find any major fish or squid predator of juvenile salmonids in summer off Washington and Oregon, but they seined 3.7 mi (6 km) or more offshore and thus missed any predators within Oregon territorial waters that may have bee attracted to the mouth of estuaries. Even if predation rates of juvenile salmonids by subadult or adult salmonids and spiny dogfish are low, their large standing stocks can make their predation in the ocean significant (Fresh et al. 1981:38, Beamish et al. 1992).
During experimental releases of hatchery coho smolts at Tongue Point, the Columbia Bar, and three offshore locations in 1983-1987, predatory birds were attracted to all sites, with an average of 689 birds at the Bar and 13-31 at other sites (Solazzi et al. 1991:252). However, the smolts released at Tongue Point contributed significantly more to ocean and gill-net fisheries than other sites even though smolts would have had to migrate pass the Bar where the greatest number of birds were observed (Solazzi et al. 1991). Relatively more of the Tongue Point fish were also caught than for those released at the control site below Bonneville Dam; this may have resulted because smolts bypassed a predation bottleneck in the lower Columbia that may have been caused by northern squawfish (Solazzi et al. 1991). The lower survival for smolts released at the Bar and into the ocean is hard to interpret and may have been a result of their having been barged and thus highly stressed (Solazzi et al. 1991:252), which may have greatly increased their predation or mortality from other factors. Shearwaters are very abundant near the mouth of the Columbia (e.g., Wahl 1984:39-41), and have been observed to catch smolts off Yaquina Bay (Comment 4). While the Tongue Point releases contributed more to fisheries, they also had higher rates of straying than those released at Bonneville (Solazzi et al. 1991).
PREDATION PLANS FOR OTHER COASTAL STREAMS. I do not have time to go through each basin, and for some basins, the status of all predators may not be clear. Accordingly, it may be necessary to examine what is known for one basin and extrapolate it to another. Thus, known information about the Columbia River and Yaquina and Coos Bays may be useful for other stream basins; this is particularly important for freshwater, estuarine, and nearshore predatory fish, which have not received much attention at coastal streams. The Introduced Fishes Predation Plan Appendix A identifies introduced predatory fish in various basins, and Monaco et al. (1990) list the seasonal occurrence and abundance of potential fish predators in each estuary. However, the occurrence of northern squawfish or other predatory native fish is not given.
As pointed out in the Avian Predation Plan, cormorants are the predator issue in Nehalem, Tillamook, and Netarts Bays. However, gulls and other birds have also been reported to be predators there (Bayer 1989:24).
Specific information about predators at Yaquina and Coos Bays is given in Comment 4. In addition for Coos Bay, many adult coho had eaten coho smolts near the mouth (Stuart and Buckman 1985), a few smolts were taken by harbor seals (Graybill 1981:43), and striped bass were found to be predators of juvenile salmon (Shapovalov 1936:262, Morgan and Gerlach 1950), although the Oregon Fish and Wildlife Commission approved a plan to supplement the striped bass population with hatchery fish in 1990 as part of the Coos Basin Fish Management Plan (Introduced Fishes Predation Plan, p. 14).
PREDATION PLANS FOR OTHER BASINS. The Introduced Fishes Predation Plan Appendix A identifies introduced predatory fish in other basins.
General Comment 8. A Predation Plan should include the option of reducing predation by decreasing the number of hatchery fish, which could increase their survival and benefit wild fish.
Hatchery fish attract predators and at Yaquina and Coos Bays, more common murres were found in years with larger hatchery releases (Comment 4). In British Columbia, Beamish et al. (1992:451-452) observed that the survival of juvenile chinook and coho decreased as the number increased, so that there was a maximum number to release before survival declined. It would be informative if Oregon fisheries data for hatchery fish could be analyzed similarly to Beamish et al. (1992:451) to determine the optimal sizes of releases to maximize survival.
Huge releases of hatchery juvenile salmon into the Columbia have not helped sustain fisheries or prevent wild fish from becoming federally listed, and hatchery fish are considered by many to have a negative effect on wild fish. Accordingly, one alternative to improve survival of hatchery fish and which also may reduce the cost to taxpayers is to reduce the number of hatchery fish released to a more optimal level that emphasizes high survival rather than mass production. For example, the Avian Plan on p. 28 mentions that "NATURE's tanks" helped improve survival.
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The Pinniped Action Plan explains the background and issues involved in pinniped predation of salmonids, including some of the legal issues unique to pinnipeds. But it would be helpful if the issues considered in my General Comments were also addressed; for example, if predation is mostly on wild or on hatchery fish. It may not be possible to determine this, but mentioning this would still be helpful in considering the OCSRI goal of restoring wild native salmon stocks.
It would also be useful if more information specific to particular estuaries or pinniped concentration spots was mentioned, like is done for Willamette Falls. Further, it would be informative if pinniped numbers in spring at Nehalem, Tillamook, and Nestucca Bays have decreased during the hazing of cormorants.
Finally, clarifying the age classes of salmon that are taken would be useful. Smolts have been observed to have been taken rarely at Coos Bay (Graybill 1981:43).
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Limiting this Plan to exotic fish predators and not having a plan for native fish predators does not fulfill the vision of the OCSRI, especially since this Action Plan identifies northern squawfish (a native species) as the most important predator in the lower Columbia (section 2-B-1 on p. 8; Beamesderfer and Rieman 1991, Poe et al. 1991, Rieman et al. 1991, Vigg et al. 1991).
Another oversight is the omission of a discussion for the introduced American shad, which is listed only as occurring at various basins in Appendix A of the Plan. The largest shad population on the West Coast is in the Columbia River, and shad populations in the Columbia have been increasing since the construction of dams and as salmon populations have been decreasing (Hammann 1982, Kaczynski et al. 1993:133, 328, Emmett 1997). The diet of adult shad in the Pacific Ocean has not been well studied (Brodeur et al. 1987:4), and adult shad during their spawning migration in the Columbia do not appear to feed (Hammann 1982). However, adults have been reported to have eaten as many 16 chinook smolts (Wendler 1967 cited in Kaczynski et al. 1993:120), and many shad offshore of North Carolina had fed on anchovies (Holland and Yelverton 1973 cited in MacKenzie et al. 1985:11), so they can feed on fish about the size of juvenile salmonids. Shad may also compete or interfere with Columbia River salmon (McCabe et al. 1983, Kaczynski et al. 1993:133-35), although the timing of their migrations reduces the potential for competition (Emmett 1997). The issues surrounding the interrelationships between shad and salmonids need to at least be mentioned in this Plan.
This Plan needs to include more examples of programs to control predatory fish in Oregon, so that the expected results of future programs could be better predicted. On p. 17, it mentions that attempts to control exotic fish in the Tenmile Lakes system failed, but it does not give the results of the northern squawfish bounty program to reduce predation on juvenile salmonids, although this program has received considerable attention (e.g., Monroe 1990) and this Plan mentions several papers from a final evaluation (Ward 1997). Perhaps, the squawfish project also failed as Collis et al. (1995:346) write about it: "In total, these efforts have achieved an exploitation rate [of northern squawfish] that is at the lower end of the targeted goal."
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I do not have time to comment on this Plan as much as I would like, so I can only touch on a few points.
Point 1. The Plan for coastal estuaries needs to recognize that the predation issue is not just a cormorant issue.
On p. 12 and 22-23, this Plan does not give much attention to predation issues along the coast and only mentions cormorants. However, about 15 years ago the issue was common murre predation (Comment 4).
In Tillamook County, where the cormorant issue has been most declared, smolt predators that have been publicly mentioned by a few fishing guides and fishermen as needing to be controlled include marine mammals (Anonymous 1986b, Erickson 1986, 1988a; Hendrickson 1987), cormorants (Erickson 1988b, Hendrickson 1988a, McAllister 1988), brown pelicans (Tillamook Anglers 1988), and great blue herons (fisherman at the 28 November 1988 ODFW meeting, Bayer 1989:12). Another fisherman (B. C. 1986) writes that even ducks are a problem: "The biologists seem to forget about all the smolt they release to the fish, ducks and seals. The predators get most of them before they get to the mouth of the ocean."
At Tillamook and Nehalem Bays, one fishing guide, Jim Erickson, recognizes that gulls can also be smolt predators. During a video presentation in the 1989 Oregon Legislature (Bayer 1989:13), Jim Erickson (1989c) testified: "Now you can see the cormorants. Now these are coming in from out in the ocean and also flying in, and you got the sea gulls right on top of them. The cormorant is the key element in this smolt predation because they drive them [the smolts] to the top, and the sea gulls are in there along with the cormorants and eating them up, like you can't imagine it."
What has been overlooked is that gulls can also prey on smolts, even if cormorants were absent. After smolt releases in Yaquina Estuary, I commonly observed gulls feeding on smolts, without any cormorants or other diving birds being nearby. Gulls would often just sit on the water, look around, and grab a smolt when it jumped nearby. Further, predatory fish can also drive smolts to the surface where they are available to gulls.
Point 2. This Plan needs to more clearly deal with the legal issues surrounding predator control.
This Plan does not adequately describe the state legal issues surrounding killing or disturbing birds. On p. 11 of the Plan, only the federal Migratory Bird Treaty Act is mentioned, but Oregon Revised Statute (ORS) 498.006 clearly indicate that the chasing or harassing of wildlife is prohibited except when lawfully angling, hunting or trapping (also see p. 19 of the Plan). One exception is if the ODFW Director declares an emergency (ORS 496.118), which the Director did in issuing cormorant harassment permits at Nehalem and Tillamook Bays to private individuals in the spring of 1988 (p. 22 of the Plan; Bayer 1989:12); to my knowledge, the Director has not done so since then. A second exception is if the Oregon Fish and Wildlife Commission acts (ORS 498.006), but the Commission chose not to issue cormorant harassment permits for Oregon estuaries in its 21 July 1989 meeting. The third exception is mentioned on p. 19 of the Plan, which notes that ORS 498.012 allows a private landowner to take or harass wildlife damaging forest or agricultural crops or livestock if they first secure a Harassing Permit from the ODFW; this ORS does not apply to smolt predation issue because the killing or harassment of predators would be on public lands and waters.
Because proponents of cormorant harassment at Nehalem and Tillamook Bays could not legally do so with current Oregon laws and regulations, they have tried to change Oregon laws. Starting in 1989 (Bayer 1989:13-14), the issue of cormorant harassment permits has been brought before the Oregon Legislature every session because that is the only other legal way for the permits to be issued. In 1995 and 1997, the Oregon Legislature passed bills allocating $25,000 per year for cormorant harassment (p. 22 of the Plan).
Point 3. Cormorant harassment has not been demonstrated to increase smolt survival.
Although proponents of harassment claim that harassment works, at least in the sense that cormorants are moved away, there is no evidence that harassment has increased smolt survival (e.g., Bayer 1989:30-32).
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