Rearing Salmon or Steelhead to Improve Fishing Opportunities
One of the fundamental reasons that large scale hatcheries are operated is to provide fish for sport and commercial fishermen. Output from large salmon or steelhead hatcheries are on the scale of millions of juvenile fish annually. The maximum production capacity of a small scale hatchery in the South Fork Trinity River basin would be 100,000 smolts annually, so it would be capable of only modest contributions to ocean fisheries. In recent years Horse Linto Creek fall chinook have shown up regularly in commercial and sport ocean fisheries. Most species within the South Fork are at such low levels that, even if populations could be increased, the objective of creating a commercial fishery through small scale rearing must be questioned.
In Chapter VII it was pointed out that harvest rates by ocean commercial and sport fisheries of some Klamath basin stocks often exceeded 70-75% (Frederiksen and Kamine, 1980; Rankel, 1980; PFMC, 1993a). Problems of harvest of over-harvest of wild salmon from some Klamath basin stocks may be continuing, with escapement rates as low as 12% in recent years (PFMC, 1993a). Maximum sustained yield calls for minimum escapements of 35%. The combined efforts of habitat restoration and small scale rearing at Horse Linto Creek only began to succeed in recent years when ocean fishing for Klamath fall chinook stocks was almost completely closed. If excessive harvest is contributing to lack of spawning escapement, it is unlikely that small scale rearing will have long-term success in reversing problems without fundamental reform of harvest management policy.
Because of varying life histories, distribution and abundance, some South Fork Trinity salmon and steelhead species lend themselves more to small scale supplementation programs than others. Each species must be individually analyzed to determine feasibility and desirability of whether or not to attempt artificial culture.
Fall chinook
This species is ready for spawning as it returns to the river and spawning migrations take place during flows that usually allow operation of a weir to allow trapping. Therefore, fall chinook salmon may be the most feasible of salmon species for small scale culture. Between Hyampom Valley and the mouth of the South Fork Trinity River, where fall chinook frequently spawn, most tributaries have barriers within one mile or less upstream of their mouth. Unfortunately, the low amount of available habitat to reseed precludes setting up a habitat refuge that could act in conjunction with a small scale rearing program similar to the Horse Linto Creek project.
Eltapom Creek has adequate summer stream temperatures but only 0.8 mile of habitat accessible to salmon and steelhead. Access to lower Eltapom Creek would be difficult in winter to tend any fish culture facility and there is probably no site suitable for building a hatchery. Butter Creek also has cool temperatures but has only 1_ miles of available spawning habitat. The channel gradient is generally too steep for optimal salmon access and there are insufficient areas of suitable spawning gravels. Butter Creek is also just above what is considered the upstream extent of fall chinook spawning grounds.
Grouse Creek has about 1¹ miles of access to salmon and steelhead below Devastation Slide. It has both thermal problems, with temperatures in the low 70's (Dale, 1990), and major sediment problems (Fuller, 1991). Some fall chinook use Madden Creek, but there is only one half mile of habitat accessible for spawning. However, because Madden Creek has better habitat conditions and water quality and access than any other lower South Fork tributary, it warrants consideration as a fall chinook rearing site. Because this area has significance to the Tsnungwe Tribe, any activities would require environmental review to protect cultural or archeological resources.
There are several questions that need to be resolved before small scale rearing using South Fork fall chinook stocks should take place. Although no data has been collected in the last two years, the population level in 1990 appeared to be critically low with only 19 female chinook salmon surviving to spawn (Chapter II). Low numbers of successful female spawners is due in part to a sex ratio among fall chinook salmon which is dominated by males (averaging 75:25), and to an average of 26% female pre-spawn mortality rate (Jong and Mills, in press). If this is related to disease introduction from hatchery fish, artificial culture could potentially increase problems. Studies are needed to determine the population level of native fall chinook salmon in the South Fork Trinity River, and to discover if disease is contributing to the skewed sex ratio and high female pre-spawning mortality in some years.
High straying rates of fall chinook in recent years, from various hatcheries (Jong and Mills, in press), raises other questions about the advisability of implementing a supplementation program for this species at this time. Although Trinity River fall chinook are from native broodstock, their fitness for survival in the South Fork Trinity basin is unknown. It is possible that poorly adapted first or second generation progeny of hatchery fish, or wild and hatchery fish hybrids, may still be returning to the basin. Natural selection could remove inappropriate genes or behaviors from past straying populations over the next several generations. If small scale rearing begins now, it may artificially perpetuate traits that otherwise would be removed by nature. Straying in recent years has diminished, and most unmarked strays now come from small scale hatcheries. Broodstock selection should avoid use of these fall chinook that have strayed from other basins. This will only be possible if 100% of all juvenile chinook reared in small scale hatcheries in the Klamath basin are marked with fin clips (Chapter VIII).
Spring Chinook
Because spring chinook salmon return to the river several months before they are ready to spawn, they may be very difficult to culture. Pre-spawning mortality may be 100% if attempts are made to hold the adults through summer. The remoteness of spawning areas also poses a logistical challenge for capturing adults when they are ready to spawn, and transferring them to a small scale hatchery.The East Fork of the South Fork Trinity River is the only tributary, other than Hayfork Creek, that has been used in the past for spawning by spring chinook salmon. The East Fork is mentioned elsewhere in this plan as an excellent candidate for restoration. Unfortunately, there has been little spring chinook spawning activity in the East Fork, or within the adjacent 10 to 15 mile reach of the main stem South Fork itself, in 1990-92 (Dean, in press). In addition, there is currently no one living in the East Fork of the South Fork basin. Therefore, the remote location may pose a serious problem to monitoring and operation of a small scale hatchery in this watershed.
Summer Steelhead
Because of a life history not unlike spring chinook, summer steelhead are not be a feasible candidate for artificial culture. Further study of spawning habits, life history, and natural limiting factors should be conducted before any small scale rearing is considered for this species.
Winter steelhead
The large number of young-of-the-year steelhead moving downstream in Hayfork Creek and the South Fork each spring suggest that habitat is not "under seeded". Steelhead that migrate to the ocean at less than two years old return infrequently as adults. Therefore, it is clear that supplementation of winter steelhead, if it is to take place, would need to raise fish to yearling size, at least. Because winter steelhead populations are not at critically low levels, there is less concern regarding potential population depletion from a small scale rearing effort. Consequently, a small scale rearing program directed toward augmenting the sport fish catch could be implemented with little damage to native stocks, if it were operated correctly.
Water temperature and flow requirements could probably be met for a fall chinook salmon rearing facility on Madden Creek. Although there is insufficient habitat in the stream to support an expanded chinook population, fish reared there might be used to increase spawning populations in the main stem South Fork Trinity River. Yearling chinook juveniles could be out-planted into various tributaries up river to imprint on areas above Madden Creek. However, rates of bedload movement in the main stem of the lower South Fork, where many of these fish would spawn, are high. For this reason, self-sustaining benefits from increasing the adult population through artificial propagation might not be realized.
If flows and water quality are improved in Hayfork Creek, tributaries near Hyampom, such as Olsen Creek, might be considered for a fall chinook rearing facility. The USFS (1991a) found maximum water temperatures of under 650 and fish reared in this creek might use the main stem of Hayfork Creek when returning to spawn.
Using artificial culture to increase spring chinook in the East Fork could become feasible under the following circumstances: fine sediment is reduced in the East Fork, reform of fish harvest management allows a population increase above current critically low levels, and staffing needs could be met. Spring chinook may also rebound in response to increased flows and cooler water temperatures in Hayfork Creek. Small cool water tributaries of lower Hayfork Creek might be used for spring chinook rearing similar to the option described for fall chinook.
Winter steelhead supplementation is already taking place in the Hayfork sub-basin at the Tule Creek rescue-rearing ponds. Greater effort is needed to monitor and evaluate the success of the winter steelhead pond rearing program to make sure that it is achieving its goals, and not interfering with dynamics of native fish populations. If fish produced from the Tule Creek ponds were fin clipped and fishing regulations were changed to allow fishing in Hayfork Creek during winter, a directed fishery could be set up that would give an incentive to Hayfork Valley residents for participation in fisheries and watershed restoration (see Chapter VII).
Salmon and steelhead stocks of the South Fork Trinity River can not be saved or restored by heavy reliance on small scale hatcheries. The quality of fisheries habitat in the basin must be improved by resolving fundamental problems, such as the over-supply of sediment and high water temperatures in the main South Fork, and the lack of flows and high water temperatures in Hayfork Creek. Salmon stocks must also be protected from harvest in the mixed stock fisheries until habitat conditions are improved. Small scale rearing can offer short term increases in the number of fish, but these more fundamental measures are needed to bring about the permanent, long term rebuilding of native stocks.
All small scale hatchery operations should be monitored closely to insure that they do not harm wild fish populations and confound restoration. All criteria for operation and/or monitoring (see Chapter XIII) must be met or small scale rearing programs should be terminated. Small scale hatcheries can be important symbols of restoration, but the level of investment in hatcheries should be a minor element of a the overall South Fork Trinity River restoration program. Annual investments in small scale culture bring only one or two years of elevated returns of salmon or steelhead, while investments in habitat restoration can provide lasting benefits for natural production. Chapter 11