SALMON HATCHERY POLICIES TO ADDRESS

THE ENDANGERED SPECIES ACT

 

December 1, 1998

Edited by

Chris Phinney, Dan Johnson, Kerstin Rotchy, John Pierce,

& Chanele Holbrook

EXECUTIVE SUMMARY

This is a proposal of ideas for the management of salmon hatcheries to decrease the negative and strengthen the positive impacts of artificial propagation of salmonids on naturally spawning populations of wild fish. These policy proposals were written by a team of fisheries students at the Evergreen State College after careful research and review of the best available science and current policies on the issues. The recommendations are addressed to the various public and private agencies involved in fisheries management: The WA. State Dept. of Fisheries, the Treaty Tribes, the Bonneville Power Administration, and any other agencies or individuals involved in the management, propagation, or harvest of salmonids.

 

The goals of hatcheries in the Pacific Northwest should be consistent with the wild salmonid strategy. Hatcheries should and be used as laboratories to help us better understand the biological needs of salmonids; maintain viable stock populations; rehabilitate endangered wild stocks; supplement depressed but naturally producing native stocks; attempt to increase genetic diversity; and ultimately seek to become of secondary necessity to naturally producing wild salmon in a healthy, restored ecosystem.

We feel that the current situation with some stocks of wild salmon being listed as threatened or endangered, and more to be listed soon, calls for immediate and decisive action on the part of all Federal, State, and Tribal agencies, user groups, private organizations, and the citizens that they represent. (Tribal participation in the State Salmon Recovery Strategy is still currently under negotiation, so the tribes’ involvement is not as of yet known.) These actions especially include making short-term sacrifices in order to reach long term goals of plentiful, healthy, and harvestable runs of naturally producing wild salmonids. While certain groups may find the immediate results of some of these proposed solutions objectionable, a long-term approach will be necessary in order to solve the problems we now face. In order to succeed we must all share a common goal of self-sustaining fish populations and a healthy environment for the benefit of future generations.

Our proposed solutions include prioritizing supplementation projects, changing methods of fertilization, creating natural hatcheries, expanding the possibilities of streamside spawning channels and using better disease control and prevention methods. This document has been divided into sections for ease of reference. Funding for these solutions will come from the general fund of which $28 million is currently being used. We do not see a need to increase funds, but rather to reappropriate funds freed by reduced production.

 

Many scientific advances have been made in the past 100 years since the artificial production of salmon was begun in Washington State, but we are still far from knowing everything about the complex and dynamic ecology of salmonids. The future role of hatcheries should be shifted away from mass production of harvestable quantities of fish towards a better scientific understanding of salmonids through experimentation and education. The following supporting document will address these issues through a presentation of alternative ideas currently being explored here in the Pacific Northwest, and a list of recommendations for new policies that would be beneficial toward the recovery of an important Northwest cultural icon, the wild salmon.

 

Prioritizing Supplementation Projects

With so many different streams and their varying degrees of salmon populations, it is recognized that there needs to be a method of prioritizing supplementation efforts. Categorizing streams, based on the best available data, into one of the Options below will accomplish this task. Opportunity A would be the most ideal, involving little intervention and low expense. The amount of intervention and expense rises as the list progresses. Opportunities C through F involve hatcheries either through propagation or monitoring and evaluation.

In order to determine what Option a stream or sub-basin falls into, Figure 1 shows a general flow chart that can be used in most situations. Keep in mind that this is meant to be general, and that there may be other factors to be considered, depending on the stream. If so, the chart would have to be adjusted to include those factors.

The best place to begin in any categorization is with the current conditions. An

existing stock or population status must be assessed, using the best available information. Three popular sources for this data are the Hatchery Releases Report, the Stock Assessment Report and the computer listing of streams planted in the State of Washington.

Once the best option has been determined, supplementation alternatives can be proposed. These must be consistent with the genetic conservation objectives of the Wild Salmonid Policy and the Endangered Species Act. Proposed alternatives would identify opportunities and constraints in that specific drainage. For example the amount of wild and hatchery fish that a specific stream can support, habitat constraints, and considerations such as tailor releasing quantities of hatchery fish at locations so as to not distress wild populations. If it is determined that a new facility is necessary, detailed master plans will be required before construction. Since the ultimate goal is to downsize hatchery operations, portable facilities would be favored over permanent facilities in supplementation projects.

 Figure 1: Supplementation Prioritization Flow Chart

(Riggs, 1986)

Genetic impacts associated with both the current status and the proposed plan need to be assessed. Three categories of genetic loss should be recognized, including: the loss/extinction of a population entity, the loss of diversity or genetic variation within a population and the loss of population identity resulting from gene flow between stocks.

Having assessed the current status, alternatives, and genetic impacts, a clear comprehensive operations plan can be developed. This plan should include a description of management approach and a statement of goals and objectives. Genetic considerations should be integrated in all aspects of the plan. Fertilization protocols are discussed in the next section. The plan should also include a set of contingency plans, specifying remedial actions for anticipated circumstances. Finally, the plan should use language understandable by a non-specialist for use as a reference document for daily management. (Riggs, 1990)

With the plan in place, monitoring and evaluation necessary for adaptive

management and planning review should be conducted. Monitoring should include the

use of returning adult counts, separating hatchery and wild fish. Methods for obtaining

these counts include temporary weirs, adult traps, and fish ladder/passage counts.

Evaluations should include genetic, demographic, and life history parameters to monitor

hatchery stock performance and impacts on wild fish. Additional counts could include

summer parr densities and redd counts

Plans may want to consider a "Before-After, Treatment-Control" stream experiment similar to that used in the Nez Perce Tribal Hatchery Program. In this type of evaluation, treatment and control streams are monitored before and at some time after a plan has been implemented. This way fish counts due to natural fluctuations will not be attributed to the plan’s effectiveness or ineffectiveness. (NWPPC, 1996)

Along with the prioritization and implementation of these plans, important research needs should be identified and research activities related to genetic conservation/ diversity and production quality should be supported. Methods of easing the transfer and keeping of information and technology need to be developed in order to facilitate the assessment, monitoring, and evaluation process. (Riggs 1990)

 

Hatchery Fertilization Methods

 

Hatcheries used in the supplementation effort must use fertilization methods to ensure a balance of wild and hatchery spawners while maintaining the highest possible level of genetic diversity. Most hatcheries have used the same, outdated methods for years. We do not know exactly what genetic combinations are favorable for survival, reproduction and fitness. Therefor, the maximum number of genetic combinations from a given number of contributors is desirable. The protocols that follow are still considered experimental, but offer the best chance at genetic diversity.

The current method is to spawn one male to one female or to spawn several males to one female, in the same container. The latter results in most of the eggs being fertilized by a single male, while the former may mean the entire loss of the genetic material of an adult if the male happens to be nonviable. This is illustrated on Tables 1 and 2. (Eddy et. al., 1996)

 

Table 1: Current Practice – "One Male to One Female" (Eddy et.al., 1996)

 

Female X

Female Y

Male A

AX

---

Male B

---

BY

Male C

---

---

Male D

---

---

 

--- equals no progeny produced

= combination lost if Male A is nonviable

 

 

Table 2: Current Practice – "Two Males to One Female" (Eddy et.al., 1996)

 

Female X

Female Y

Male A

AX

---

Male B

BX

---

Male C

---

CY

Male D

---

DY

 

--- equals no progeny produced

= combination lost if Male A is nonviable

 

In Table 1, only two genetic combinations are produced. If one of the males happens to be nonviable, only one genetic combination is produced and the genetic material of Female X is lost. In Table 2, four genetic combinations are produced. This number drops to three combinations and a loss of 25% of the genetic material if Male A proves to be nonviable. However Female X has lost 50% of her contribution.

The Imnaha Chinook Salmon Program has proposed new spawning protocols, including matrix spawning, that have been supported by the Lower Snake River Compensation plan of the U.S. Fish and Wildlife Service. These protocols are meant to preserve genetic diversity and to avoid artificial or intentional selection. In keeping with this intention, the following measures are included in this program.

All available (collected), fully mature broodstock must be spawned. When possible, spawn at least 100 of each sex. If there are less than 100 of either sex, matrix spawning protocol should be used. Table 3 illustrates spawning protocol scenarios based on the ratio of males to females and the total number of spawners. An attempt must be made to avoid artificial or

 

Table 3: Spawning protocol scenarios and selection. (Eddy et al., 1996)

No. Females*

No. Males

³ 100

³ 100

< 100

< 100

³ 100

³ 100

< 100

< 100

Sex Ratio

1:1

1:1

Not 1:1

Not 1:1

Outcome No matrix used.

Spawn 1x1.

Use matrix.

Spawn 2x2.

Use matrix.

Spawn 1 x ?,

Depending on sex ratio.

Use matrix.

Structure depends on sex ratio (usually not more than 2x4).

 

* The counts used in this program were based on using 50% of both the hatchery

produced spawners and the naturally produced spawners.

intentional selection. Broodstock must be collected from all components of the population without bias toward run timing, age, or size. Jacks and precocious parr should be included in balance with their presumed contribution rate to natural populations.

Each individual should have the opportunity to make an equal contribution to the next generation. Each male should be given the chance to fertilize the same number of eggs. If matrix spawning is used, the same matrix structure should be used throughout the season. Avoid pooling semen from multiple males in the same container. Milt from each male should be combined with an equal amount of eggs in a separate container.

This program is the best known way of preserving genetic diversity and giving the highest number of genetic combinations a chance. Table 4 illustrates the outcome of a typical 2 x 4 matrix.

Table 4: Typical 2x4 matrix (Eddy et.al., 1996)

 

Female X

Female Y

Male A

AX

AY

Male B

BX

BY

Male C

CX

CY

Male D

DX

DY

 

= combination lost if Male A is nonviable 

In this scenario, eight genetic combinations are created. If Male A again is nonviable, 25% of the genetic material is lost, but there are still six combinations left. In Table 3, only three combinations remained in this same situation.

In large populations where genetic diversity is not the issue, a one to one fertilization method can still offer a satisfactory amount of variety. However in populations containing less than 100 of either sex, the matrix spawning protocol offers the most efficient use of the genetic material available. Furthermore, this protocol involves practically no expense, just a slight change in practice and minimal training of staff.

Natural Hatcheries

The standard hatcheries today are in place for one reason, and that is to pump out as many pounds of fish as possible. With the wild salmonid policy, we will be looking to reform many of the current facilities by shifting the emphasis from pounds of production to survival rates and a more natural usage of facilities. We will be looking at a project that is taking place on the Yakima River at the Cle Elum hatchery as a template and a stepping stone into the future of hatchery salmonid production.

The hatchery is actually called a supplementation and research facility and is funded by Yakima Nation, Washington Department of Fish and Wildlife, Bonneville Power Administration and the Northwest Power Planning Council. This is a state of the art research facility and will provide new models for rebuilding endangered stocks throughout the Northwest.

The hatchery will be using two experimental treatments, Optimal Conventional (OCT) and Semi-Natural (SNT). The biological specifications have been completed for this specific project. The control and experimental variables of the treatments(OCT and SNT) will be described in detail to assure that the fish culture facilities will be designed and operated as a production scale laboratory to produce and test supplemented salmonids. Product specifications of the treatment groups are proposed to serve as the generic templates for developing greater specification for measurement of product attributes. These product specifications will be used to monitor and evaluate treatment effects, with respect to the biological response variables (post release survival, long-term fitness, reproductive success and ecological interaction). (Working Draft-Cle Elum Hatchery)

Some of the components of the fish culture facilities are defined, described and specified according to physical features of the other hatcheries around the state to permit technology transfer of new concepts, procedures, and methods to existing facilities. The two experimental treatments for the first five year block compare the effectiveness of a state of the art optimal convention OCT rearing method to one form of semi-natural SNT. The experimental variables were selected because:1) They offer promise for increasing post-survival and producing wild like salmonids, and 2) only limited production scale research has been done on these variables. The experimental variables selected for research are: live foods, feeding methods, predator avoidance training, exercise, overhead cover, in-water structure, substrate, and sub-surface filtration.

The SNT is a collection of experimental strategies for producing hatchery-reared salmonids that exhibit behavioral, physiological, and morphological attributes of their wild counterparts. It is assumed that rearing salmonids in a semi-natural, cultured environment can produce wild-like attributes. The SNT raceways consist of high dissolved oxygen levels, overhead cover, in-water structure, and natural substrate, with live and pelletized food introduced below the surface. The SNT rearing expectation is that this semi-natural habitat will: 1) improve immuno-competence by alleviating environmental stress: 2) promote the development of natural cryptic coloration and anti-predator behavior; 3) increase foraging efficiency; and 4) reduce the genetic selection pressures induced by the artificial environment. Although founded on the best scientific information, the SNT rearing environment is an experimental treatment with uncertainty and risk.(Working Draft-Cle Elum Hatchery).

 

Optimal Conventional Treatment

 

Hatchery Rearing

The spring chinook production goals of the Cle Elum Hatchery are 810,000 spring chinook smolt weighing 54,000 pounds. The production population will be separated into 18 groups, nine of which will be reared under OCT. The OCT fish will be reared under conditions in the hatchery and at off-site acclimation ponds (designated areas in the upper tributaries where they will eventually be released) that are expected to produce the highest quality and most fit hatchery fish.

Prior to the end of their rearing cycle ( approx. one year post swim-up), all experimental groups will be transferred to off-site rearing ponds for acclimation and release. This transfer will occur in January to assure their presence at the release site before the in thyroxine and other physiological indicators associated with smoltification and effective homing.

Rearing Density- controlled variable

The maximum rearing density is 0.75 pounds per square foot of rearing space following the chinook salmon yearling standard adopted for the design of upper Columbia basin facilities including Eastban Hatchery(PUD NO.1 Chelan Co. Wa.1988) . Maynard (1993) summarized the results of spring chinook rearing density experiments showing survival and contribution advantages provided by lower than normal pond loading rates.

Rearing Vessel -controlled variable

By definition, OCTT rearing vessels should represent the current Pacific salmon production standards in length, width, and depth, and inflow. Raceway vessels typically conform to a ratio of 30:3:1 for length, width and depth, respectively (Piper et al. 1982).25 The experimental design will assume a raceway design standard of 100’ in length x 10’ x 3.5’ (operating depth) as the optimal conventional standard of raceway dimensions and current WDFW designs.

Raceways will be installed as separate but adjacent units 12’ apart. Standardization of vessels is a critical factor needed to reduce experimental variation among vessels.

 

Inflow - controlled variable

Flow will be provided as necessary to maintain a high level of dissolved oxygen(not less than 7ppm) at the outflow. In particular, raceways will be supplied with 1.44 cfs (650 gpm) through a pond-width manifold following current WDFW facility design. In addition, outlet screens will also span the width of the vessel. 

The fish growth model uses a variable temperature profile with constant temperature form May into September for spring chinook culture. Accordingly, two water supplies will be required for the culture of spring chinook at Cle Elum Hatchery:(1) a production quantity surface water source to provide a fluctuating environment (water quality and temperature) needed to properly induce smoltification, and (2) a groundwater system to support production during summer when surface water temperatures exceed the desired range for spring chinook production.

 

Fish Feed/ Diet-experimental variable

The majority of spring chinook reared at public fish culture facilities at the inception of YKFP facility planning were started and reared to approx. 400/lb using "closed-formula" semi-moist diets. The remainder of the production was commonly accomplished through the use of Oregon Moist Pellets formulation following bid specifications. Use of semi-moist feed in full-term rearing of spring chinook was limited and not fully evaluated at that time. Semi-moist diet trials had, however provided favorable comparisons (growth, conversion, size variation, physiological measures) between spring chinook reared on OMP and semi-moist diets (Hager 1992). More recently, the use of a broader mix of closed formula moist, semi-moist and dry diets with more general specifications has become the norm in chinook production.

Diet Recommendations for OCT-reared fish are:

-Start fry on moist or semi-moist diets.

-Rear juvenile on moist or semi-moist diets until approx. 1 gram average size.

-Complete rearing on OMP or similar project-specific formulations.

Feeding Methods: experimental variable

First feeding of spring chinook will occur following yolk absorption when at least 90%

of the population is free swimming. Approximately 1,665 temperature units at 50 f are required for chinook fry development prior to the time of first feeding(Senn 1993).

 

Acclimation Rearing

Following the preferred experimental design (Hoffman 1994; Hopley 1995) three acclimation sites with six ponds will be constructed. All ponds will be supplied from on common water source and will represent each of the two treatments (OCT and SNT). Two of these sites will be located on the Yakima River between Ellensburg and Keechelus Dam and the other on the Teanaway River. The site selection process will consider biological criteria important to supplementation objectives.

Each acclimation pond will be sized to hold 45,000 spring chinook salmon. These ponds will be of a common design with operational flexibility sufficient to accommodate experimental design requirements and, by site, will have common water supplies and drains. Predators will be controlled to assure fish inventory and experimental integrity. The OCT group will be reared in acclimation ponds w/o any modifications thereby representing normal practices.

We know that acclimating salmonids not only gives the wild fish a better chance for survival, but has been shown to increase survival of outgoing smolt. (Figure 2.)

 

 

Figure 2: Acclimating salmonids in the wilds near Hood River, Oregon (Jennings, Mick & Michael Lambert, 1996)

General Fish Culture: control variable

All ponds will be visited daily by project staff to assure project integrity and to do routine fish culture work ( fish feeding, cleaning intake and outlet screens, verifying flow, recording temperature and other factors).

Because of the rearing density and anticipated low water temperature, it is unlikely that disease treatment will be required during this phase of life. However any disease treatments will be applied consistently with proper experimental methods.

 

Semi-Natural Treatment

"Semi-Natural Treatment- an experimental treatment that creates a more natural environment to incubate, rear, and acclimate fish. The intent is to raise and release fish approximating the characteristics and behavior of their naturally produced counterparts" (YKFP 1992)

  1. Hatchery and Acclimation Rearing

 

Rearing Density: controlled variable

Since the benefits of lowering rearing density on survival and size have been demonstrated (Table 5. Banks 1990) and the project has chosen an optimal rearing density for OCT fish, the SNT fish will be reared at the same density as OCT fish in raceways and acclimation ponds.

Table 5. Effects on rearing density of Fall Chinook at Spring Creek Fish Hatchery (Banks 1990)

 

Rearing density (Fish stocked/pond X1000)

91

182

273

Release Date

March

3.7

3.6

3.6

(grams/fish)

April

7.1

6.7

6.7

(grams/fish)

May

12.1

11.4

11.1

(grams/fish)

Rearing Vessel: controlled variable (see OCT)

Inflow: controlled variable (see OCT)

General Fish Culture: controlled variable

Routine fish culture practices other than those discussed below will be standardized across all treatments.

Fish Feed/ Diet: experimental design

SNT fish diets will be supplemented with live organisms throughout their hatchery rearing period to condition released salmonids to forage more effectively on naturally occurring food organisms. They will otherwise be the OCT diet or possibly with an alternate prepared diet resembling the constituents of natural feed. Diets for SNT use will be manufactured following specifications that provide the desired nutrition requirements and appropriate feed delivery characteristics. SNT & OCT will be fed equal amounts of caloric feed.

 

Feeding Methods: experimental variable

Pelletized feed will be introduced underwater from a specialized feeding system at a frequency appropriate to achieve proper growth.

The feeding system will consist of 5 feeding stations located along the side walls of each SNT raceway wall and continuous water supply used to deliver the feed to the fish. Each feeding station will be provided with a hopper for manual or mechanical addition of feed and two distribution tubes that discharge feed above the raceway bottom (Knudson, 1997).

  1. Behavior Techniques: experimental variables

 

Predator Avoidance Training: Avoidance training methodology will be applied to SNT experimental groups to allow fish to avoid predators. Fish will be trained to avoid predaceous fish, birds, and possibly mammals.

Conditioning may be achieved by placement of predators in cages in rearing vessels.

3. Exercise: experimental variable

Exercise is envisioned as a means of improving fish performance. This may be accomplished be the use of pumps or temporarily configuring vessels water supplies to create increased water velocities in raceways and acclimation ponds.

  1. Vessel Modifications: experimental variable

It is expected that standard raceways will be modified to improve fish quality and ultimately to achieve higher post-release survival.

 

Raceway Color

Donnely (1992) and Maynard (in preparation) indicate that fish exposed to a rearing environment of color matching that of the natural background of the area into which the fish will be released can be cryptically adapted. A period of at least seven weeks is required for full chromatophore expression. Raceways will be modified to achieve the appropriate condition as determined by field use of colorimetric methods. The raceway walls will be painted to resemble stream background coloration.

 

Overhead Cover

Overhead cover will be applied at a covered-to-uncovered ration of 4:1. Initial planning envisioned use of flat panels that would rest on vessel walls.

  1. Raceways: Use of overhead cover will allow fish to become adapted to natural structures to avoid predation. It is expected that the effect of an undercut bank will be achieved by using 12 5ft diameter floating hoops covered with camouflage netting per raceway (Knudson, 1997)
  2. Acclimation Ponds: Floating hoops will also be used to provide cover for acclimation ponds. The use of floating covers will facilitate fish culture activities and meet experimental needs as well.

 

5. In-Water Structure: experimental variable

Use of in-water structures is envisioned to create a varied rearing environment in both raceways and acclimation ponds. While specifics are not available, it is expected that the materials used may be as simple as denuded vegetation or more complex, being constructed to the need.

  1. Substrate: experimental variable

Vessels will be designed to allow randomization of vessels and substrate between years as required by experimentation. Space (0.5 ft) will be provided in each vessel to allow for the use of gravel or concrete panels. Use of painted substrate has also been envisioned.

  1. Raceways: the bottom of each SNT raceway will be painted with several colors using stencils simulating rock shapes.
  2. Acclimation Ponds: ponds will also be painted to simulate substrate.
  1. Sub-surface Filtration: experimental variable

A rough substrate has the potential to collect settleable solids and improve environmental conditions within the formal rearing vessels through the action of decay organisms.

  1. Raceways: The bottom of each SNT raceways may be equipped with a substrate biological filtration system to enhance decomposition of organic materials that cannot be removed.
  2. Acclimation: does not apply

 

Spawning Channels

Spawning channels (human created replicas of naturally pristine spawning habitats) will play an intricate, evolutionary role with the usage of hatcheries as an ever increasing experimental treatment in an integrated regional rebuilding program (NWPPC, 1996) for salmonid recovery. The utilization of spawning channels should result in the re-evolvement of numerous localized salmonid populations by re-establishing and creating spawning habitat lost. In the bureaucracy that has manifested the modern hatchery system, spawning channels have never maximized their potential as a mass production hatchery alternative.

Spawning channels allow for the creation of and increase in, returning localized brood stock. An advantage of spawning channels is inherent of the capacity for natural sexual selection to occur. Thus, the most naturalistic maintenance of genetic diversity under human protection of controlled mediums is retained. The implementation of spawning channels will go hand and hand with the habitat restoration projects of formerly inhabited environments. The goal is the creation of the imperative habitats needed for salmonid spawning and rearing. Spawning channels will play an integral part of state hatcheries operations. The creation of as naturalistic salmonid as possible within a human created and controlled environment results in an increase of sustainable amounts of salmon and minimal wild salmonid modification.

 

Cost Effectiveness

The creation of spawning streams involves the cost of construction and materials, and in some instances, land acquisition. Once the channel is constructed, the stream requires minimal further financial support or physical maintenance (removal of silt). Spawning channels may require an investment of up to $50,000, but require very little capital to keep flowing after the initial cost. Mass production hatcheries cost millions to construct and thousands to keep sufficiently maintained. This is a lower costing, more naturalistic approach, requiring much less human intervention in the salmon’s life cycle with greater opportunity for salmon return.

 

Construction

Each project will be individually and specifically suited to re-create the unique needs of the local salmonid population’s ideal enriched spawning habitat. Various projects will be assessed and initiated through a process overseen be the Dept. Of Fish and Wildlife.

1. Groups or individuals that wish to organize and develop a spawning channel project can submit their proposal and go through an Environmental Assessment Review Process. (These groups may include tribes, businesses, schools, environmental groups etc.)

2. Allocation of funds and grants will be determined by the Department of Fisheries and Wildlife. This department will also oversee fiscally and determine what minimal physical requirements must be accomplished.

                3. Construction will be hired out of private sector.

4. Project maintenance administered by Department of Fisheries and Wildlife and associated volunteers (stream teams, schools, etc.).

5. Financial assistance will be provided to individuals in the private sector who wish to construct such a project on personal property (such as agricultural lands). Financial compensation could be up to 50%.

 

Physical Requirement Facts:

Channels will be armored (along with an impervious blanket) with gravel to prevent erosion. Pools and riffles are to be created through precise placement of rocks and gravel. Rock weirs may be constructed at the heads of deep pools and pool tailouts (areas of fast water habitat), these will be created by larger gravel. Large and small woody debris will be added.

Local riparian zone planted (native shrubs and trees).(A diversity of native insects and invertebrates are known to be established with in 8 months.) (Davis, 1997) Head gates will be added the diversion sites to control water levels. Spawned out carcasses should not be removed (to add essential nutrients into stream ecosystem).

 

Conclusion

The utilization of spawning channels will prove to be increasingly cost effective by eliminating the need for continual human attendance and facilitation of the site. The projects should not exist beyond dammed areas (unless for non-anadramous fish). The projects should eventually replace the existing/defunct hatchery sites that have been proven derogatory and negative to the watershed ecosystem. These projects should be individually conceived and developed according to each’s areas unique native ecosystem. They should replicate the natural environment exact as possible (native plant species, gravel, and carcasses only, flow and temperature revealing the environment as if it were produced under ideal natural conditions). Results are to be monitored in scientific fashion by the US Dept of Fisheries and Wildlife.

SALMONID DISEASES AND TREATEMENT

Introduction

The diseases that affect both hatchery and wild salmon populations are a huge issue in the decline of all salmonids. Both infectious and non-infectious diseases are shared among wild and hatchery salmon populations. The water quality and habitat are the key to preventing and destroying most diseases in all salmon populations. Through past studies and research, it has been proven time and time again that the prevention of disease is the best way to fight most all-common infectious and non-infectious diseases. Coming up with the most "economical " way of doing this is another issue.

The following document will provide known facts and summaries of the disease problems and currently used methods of prevention and treatments.

 

Infectious and Non-Infectious Diseases

Infectious diseases are passed through populations involving living agents and have caused most losses in salmonid populations. These living agents are grouped together according to the nature of the infectious agent involved. Closely related organisms can also cause diseases and is therefore, dependent on the knowledge of the differences between them. (Roberts and Shepherd 1974)

Water quality is a huge factor in disease control. The abundant bacteria, viral, parasitic, fungal, and microorganisms that live in the water, are reflective of pollution, agricultural run off, chemicals and pesticides that help to feed or increases growth of these organisms. Because of these changed or "contaminated" water sources, which are extremely difficult to control, the fish are exposed to it in the fry, smolt, and adult stages. Depending on the type of bacteria and micro-organism, the diseases will either kill them before they migrate to salt water, during the time they are in salt water, or on their return when they become weak and exhausted from their long trip back.

Non-infectious diseases that are more abundant are usually internal or genetic, which are also reflective of water quality. Water temperature, oxygen levels, quantity of flow in the streams, and altered aquatic habitat will inherently stress the fish and encourage some of these diseases to occur. These diseases which are encouraged by the environment can stay within an individual fish or spread through secondary infections in the water source.

 

Prevalent Bacterial Diseases

Furunculosis or "furune" is a type of lesion caused by a bacterium called Aeromonas salmonicida. It is generally a warm (56 to 70 dF) water-borne disease, which appears to affect the fish through outer epidermal abrasions or the digestive tract. It becomes localized and then releases a toxin that destroys the fishes immune system leading to a general blood infection and will eventually kill the fish.

Scrapfish that live in the streams are especially notorious as being a source of infection for young salmon in the hatchery ponds. These fish have also been found to harbor drug-resistant strains of the bacterium. They will live below the hatchery during most of the year and then move upstream above the hatchery to spawn. The dead carcasses that carry the diseases will then affect the young salmon in the ponds before their release.

It has been found that the furunculosis bacterium may occur on the eggs taken from an infected fish, although infection of the fry has never been shown. Furunculosis epidemics in salmon appear to be self-limiting, especially in coho. The total loss in untreated hatchery fish will usually be less than 10%, even though some individual ponds may be as high as 20%. The low percentage seems to be due to their ability to develop antibodies against the disease.

Columnaris is a bacterial disease caused by myxobacterium called Chondrococcus columnaris. The bacterium has a strange way of piling up into large distinctive columns either on the gills or epidermal lesions. Usually the bacteria are not found systemically until a relatively large amount of external skin or gill damage have taken place, extensively the penetrated blood vessels. This disease affects most species of salmonids reared in fresh water, but the bacteria can not survive in salt water.(Roberts and Shepherd, 1974)

There has been no evidence of localized infection in the various internal tissues; it would appear the bacteria entered the blood stream through the external lesions and are not directly involved in causing death. They are extremely important as they are able to survive the usual external treatments and probably serve as a source of reinfection of the external tissues. The bacterium is a pale yellow to orange color that grows in the lesions throughout the body and gills.

High virulent strains occur when the water temperature reach 60 dF which mainly attack primarily the gills while the low virulent strains occur when water temperatures reach 70 dF which attack primarily the body of the fish. The damage caused by the lesions throughout the body and the gills usually points to suffocation as the primary source of death due to this disease. (Wood, 1979)

The disease is usually treated with low levels of Furox 50 or Sulfamethazine in their food source.

Low-Temperature Disease, or cold-water disease, is caused by the myxobacterium Cytophaga psychrophila. The optimum temperature for the growth of this disease is 40 to 50 dF in the hatchery production ponds. This disease is primarily the disease of young coho salmon and some sockeye salmon. The disease can be extremely devastating resulting in losses of over 50 %. The severity of the diseases seems to result on the stage of development of the fry when it starts.(Roberts and Shepherd, 1974)

The disease typically starts to attack the thin skin covering the yolk sack among young fry. The fist evidence of the disease is when the screens in the incubators begin to clog because of all the yolk fragments that have been spilled out. If the fry absorb their yolk sacks with the disease, the most obvious symptom is the erosion of the peduncle area (just behind the dorsal fin) and eventual tail loss, leaving only the spinal cord and a few fin rays attached to the living fish. (Wood, 1979)

The standard treatment for this disease is a Furanace - 10 bath or Terramycin or Sulfamethazine in their food source. The type of treatment depends on the amount of fish infected and how advanced the disease appears on most of the infected stock.

Kidney Disease [BKD] is caused by a small bacterium, which has not yet been given a definite name. It has been tentatively labeled as a new species belonging to the genus Corynebacterium. The optimum temperature for this disease to thrive is 52 dF or higher, although some outbreaks have occurred at lower temperatures due to a prolonged incubation period following the initial infection. The bacteria can be contracted to the fish by infected food, or other fish in the hatchery through the water supply.

This disease can affect all species of salmonid, some are more susceptible than others. Once the fish has the bacteria in their body, it travels through the blood stream, multiplies slowly and forms foci of infections. These foci are in the kidneys, forming white pus blisters and ulcers. These blisters move into the muscle tissue and then push outward to the outer skin and open into large lesions. Their liver, spleen and heart may also be centers of infection, and have grossly visible lesions of the organs.

As the infection develops and the kidney breaks down, some fish will develop excess fluid in the abdominal cavity until their bellies are greatly extended, distended eyes, "pop eye", may accompany this symptom.

The disease is treated with Sulfamethazine in their food source, which has proven over the years to have a limited affect on the disease, or Erythromycin thiocynate, which is also used in their food source and has proven to be fairly affective, although it is very expensive. (Wood, 1979)

Costiasis is a disease caused by a flagellated protozoan called Costia (necatrix or pyriformis) that lives on the fish as a parasite. This disease affects all species of salmonid reared in fresh water. It has also been detected in several different temperatures at different hatcheries. How many Costia parasites does it take for it to be called a disease, depends on the deviation from the "normal" state of health the fish should be in. Death, lack of appetite, flashing, slow growth rate, etc. Costia is a disease that can cause death without a lot of tissue changes.(Wood, 1979)

Costia can easily be overlooked during microscopic examination, being that they are invisible to the naked eye. The first symptoms of the disease, especially in young fish, is a lack of appetite and general listlessness. "Flashing" can be evident if the external body surface is infected but is usually not seen if the gills are infected. More infected fish may have a bluish color slime over their body, unless they are younger than five months they will die.

This disease usually becomes a problem in the spring, with the greatest number of outbreaks in April and May. It has a more severe effect on younger fingerlings, due to being more prone to infections than older fish. Costia apparently is not effected by salt water as many of the bacterial diseases are. Fish that are treated for the disease recover well and usually carry on in a normal manner out to sea.

It is almost impossible to prevent this disease from occurring, but keeping populations down in the rearing ponds and maintaining nutritional health is a good way to keep number of outbreaks to a minimum. The disease once it has occurred can be treated with a Formalin bath during an appearance of the disease or once fingerlings reach 60 to 80 days of age will prevent a build up of the Costia protozoa to harmful levels.

Ichthyophthinus "Ich" is a disease caused by a large ciliated protozoan called Ichthyophthirius multifilis, living on the fish as a parasite. This disease affects most species of fish that are fresh warm-water rearing such as, Chinook, Coho, Steelhead, and Rainbow trout. It is also the most common reported parasite on fish around the world than any other single parasite.

"Ich" is unlike any other parasite in the sense that it burrows under the epidermal layers of the gills, fins and skin, and then will feed on the host’s tissues until it matures then drop off and settle at the bottom of the pond and reproduce by fission. Depending on the water temperature, they can reproduce 30 to 1,000 young between one or a couple days. Then the young will swim around in search of a new host and the cycle starts over. This whole cycle may take as little as four days in water at 70 dF or longer than 30 days in water at 50 dF.

"Ich" is the only protozoan parasite large enough to been seen with the naked eye. It appears as gray-white specks, like salt grains on the body surface of the fish. In young fish, considerable "flashing" may occur, and show erratic spurts of activity. As the parasite develops, the fish become listless and dark in color, occasionally a blue film develops over the surface of the fish. Faster moving low level water in the rearing ponds can wash non-parasitic stages out of the ponds before epidemic out break proportions are reached.(Wood, 1979)

Once the disease is detected it can be treated with a Formalin bath for 1 hour daily until the fish are free of the parasite. Treatments can be every other day at water temperatures below 60 dF.

IHN Virus (infectious hematopietic necrosis) is a disease caused by a virus which has had variety of names over the last twenty years, they are SSVD [sockeye salmon viral disease], CRDS [Columbia River sockeye disease], OSD [Oregon sockeye disease], and SRCD [Sacramento River chinook disease]. This disease attacks the blood forming tissues in the kidney. The optimum temperature for the disease to take hold of a population is 45 to 55 dF. The disease seems to affect chinook, and sockeye, both at young ages. The external symptoms differ with the age and species of fish. There are many different symptoms but the most common seem to be lethargy, dark coloration, "pop-eye" in the fish that are surviving, and hemorrhaging under the skin and swollen abdomens in the fish that had died.(Wood, 1979) (American Fisheries, 1997)

The disease can only be detected by tissue culture isolation at the time of spawning in adult fish. It is not possible to detect the carrier state in the survivors of an IHN epidemic unless the fish are examined at the time of sexual maturation, then only the eggs can be certified as coming from and IHN free stock. There has been no effective disinfecting procedure developed as of yet, and so it is imperative that no eggs be taken from any runs known to have been IHN positive in the past or from any exotic origin unless they can be proved to IHN free stock. (NWPPC, 1996)

Saprolegnia is a fungus condition called Sprolegnia parasitica present in every salmonid habitat. It is generally considered to be a secondary invader, taking advantage of an abrasion or lesion on the skin surface to establish itself, forming cotton-like patches commonly seen on adult salmon during the spawning season or young salmon during the rearing season.

The removal of the protective slime on the fish by handling will often permit the fungus and any underlying bacterial and parasitic infections to invade and become the primary causes of a disease outbreak. This should be controlled at all times to eliminate any secondary infection therefore, handling should always be done gently as possible.(Wood, 1979)

Dead eggs in the hatcheries or the wild runs will always become infected with saprolegnia or other mold. During many disease outbreaks that spread rapidly and kill quickly, the fish usually die before the fungus has the opportunity to develop, but the slower diseases will usually allow an opportunity for secondary infections to develop and advance the losses in runs or ponds.(Roberts and Shepherd, 1974)

Treatment of fungus patches on individual adult salmon of all species may be advisable in rare instances by swabbing the infected areas with a concentrated solution of malachite green [being careful not to get the solution on the gills]. This procedure is very time consuming and should only be considered if the fish is valuable enough to warrant individual treatment.

Mass treatment of young salmon with malachite green is not recommended, as it is very toxic to young fish for long periods of time. However it is standard practice to dip all fingerlings that are fin clipped at the time of marking [while they are being handled anyway] in a concentrated solution of malachite green before returning them to the ponds.(Wood, 1979)

Proposed Solutions

Due to the habitat and water quality issues that need to be addressed immediately, solutions for disease control are going to be extremely difficult. The best way to practice disease prevention is to reduce fish production in the hatcheries, and focus on quality of fish production. Ultimately, less fish in the rearing ponds and runways will cut back on stress through less crowding and fighting for food, and numbers of fish carrying diseases to spread throughout the ponds.

Water quality issues need to be addressed in the fact that surface water carries most of the infectious disease that can be easily spread throughout the hatchery. Surface water is crucial for imprinting the smolts before releasing from the hatchery. Well water can be used, but imprinting becomes very difficult on young salmonids. Specific odors in the surface water will imprint the smolts for a specific tributary. Therefore, super filtering of surface water is crucial to eliminate bacteria, protozoan, and micro-organisms that will invade and create disease throughout the hatchery.

Lastly, current and future diseased fish need to be destroyed and their carcasses disposed of in a way that the disease and bacteria can not return into the environment and ultimately contaminating the water source all over again. Eggs from any known infected stock also needs to be destroyed in the same way. These diseases have to eliminated at the first encounter or the chance of the diseases spreading will become a huge risk. In extreme cases of genetic importance can these steps be altered or re evaluated. We do not want to loose sight of the main goal of re-establishing wild stock and their native runs, but the disease control issues must remain the first priority if the wild stocks will ever stabilize and return healthy.

We have no true way of determining the entire realm of destruction that these diseases have done. It will take many years to bring healthy stocks levels back to a minimal standard, but continuing the way that we have for the last 100 years will surely continue to deplete what little chances we have left.

 

CONCLUSION:

We believe that hatcheries, in accordance with the new Salmonid Policy, will be used in the near future as tools for restoration, rehabilitation and scientific research for the Pacific Northwest region. Cutbacks on hatchery numbers will eventually allow for more salmonids to spawn naturally, encouraging natural selection and biodiversity to re-establish themselves in their the native runs. Hopefully with time, and the re-establishments of habitats the runs will spread to streams and tributaries that have not existed in the past, creating new runs and ultimately new genetic diversity.

We would like to present a simplified list of recommendations to address the problems currently facing hatchery propagation of salmon.

 

 

 

 

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