### VI. DEFINITIONS

Artificial propagation - Any assistance provided by man in the reproduction of Pacific salmon. This assistance includes, but is not limited to, spawning and rearing in hatcheries, stock transfers, creation of spawning habitat, egg bank programs, captive broodstock programs, and cryopreservation of gametes.

Bottleneck - A sharp reduction of a breeding population's size to a few individuals. The genetic consequences of a bottleneck, especially the loss of genetic variability, depend on both its magnitude and its duration.

Captive broodstock program - A form of artificial propagation involving the collection of individuals (or gametes) from a natural population and the rearing of these individuals to maturity in captivity. For listed species, a captive broodstock is considered part of the evolutionarily significant unit (ESU) from which it is taken.

Crossbreeding - Reproduction between two distinct conspecific gene pools (compare with "hybridization," which generally refers to reproduction between distinct species or higher taxa). With respect to listed species of Pacific salmon, crossbreeding generally refers to interbreeding between individuals from different evolutionarily significant units (ESUs).

Cryopreservation - Preservation of gametes at very low temperature (e.g., use of liquid nitrogen to freeze sperm for later propagative use).

Domestication selection - Natural selection that operates on a population during artificial propagation to produce adaptations to the culture environment (Doyle 1983). Domestication selection typically requires more than one complete life cycle to produce a permanent phenotypic response. Domestication selection tends to eliminate fish that cannot adapt well to the captive environment, which may include some fish that are well-adapted to their natural environment.

Effective population size (Ne) - A mathematical construct that takes into account skewed sex ratio and variance in progeny number, as well as the actual number of breeders, to estimate the number of effectively breeding individuals in a population. Ne is the size of an idealized population (i.e., one in which sexes are equally represented, parents are randomly mated, and numbers of progeny are randomly distributed among families) that shows the same rate of loss of genetic variability as the observed population (Falconer 1981, Lande and Barrowclough 1987). 

Evolutionarily significant unit (ESU) - A population or group of populations that is considered distinct (and hence a "species") for purposes of conservation under the Endangered Species Act. To qualify as an ESU, a population must 1) be reproductively isolated from other conspecific populations, and 2) represent an important component in the evolutionary legacy of the biological species (Waples 1991a). (In this document, the term "stock" is synonymous with "population.")

Fitness - An individual's contribution, relative to other individuals, to the breeding population in the next generation. Measures of an individual's reproductive success such as its survival, fertility, and age at reproduction, are typically used as indicators of fitness. The fitness of a group of individuals (e.g., a population) may be defined as the group's ability to maintain itself in its environment. It is therefore a composite measure of individual reproductive success. Endler (1986) discusses the fitness concept further.

Full-sib family - A group of individuals that shares the same two parents (i.e., brothers and sisters). Members of a half-sib family, by contrast, share only one parent.

Genetic drift - The stochastic process of genetic change through random shifts in allele frequencies. These changes can lead to loss (or, alternatively, fixation) of alleles. Genetic drift can eliminate gene polymorphisms and thereby erode genetic variability, and its effects are greatest in populations of small size.

Hatchery - An artificial propagation facility designed to produce fish for harvest or spawning escapement. A conservation hatchery differs from a production hatchery in that it specifically seeks to supplement or restore naturally spawning populations.

Inbreeding depression - A reduction in fitness resulting from mating between close relatives that occurs by chance in small populations or by assortative mating in large populations. Inbreeding depression is a consequence of the expression of deleterious recessive alleles as homozygosity increases; therefore, it depends largely on dominance, or interactions between alleles within loci (Falconer 1981, Lynch 1991).

Introgression - Incorporation of genetic material from one gene pool into another by hybridization or crossbreeding, followed by backcrossing between crossbred individuals and fish from the parental population(s).

Jeopardy - The National Marine Fisheries Service and U.S. Fish and Wildlife Service have defined the phrase "jeopardize the continued existence of [a listed species]" to mean "to engage in an action that reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of that species" (50 CFR 402.02).

Listed species/listed population/listed evolutionarily significant unit (ESU) - For Pacific salmon, any ESU that has been determined to be threatened or endangered under Section 4 of the Endangered Species Act. 

Natural fish - Fish that are progeny of naturally spawning parents (Waples 1991a). Natural fish thus spend their entire life cycle (except perhaps for brief periods in conservation facilities such as fish ladders or transportation barges) in natural habitat. (See Bjornn and Steward (1990) for a suggested distinction between the terms "natural" and "wild" fish.)

Outbreeding depression - A reduction in fitness that results from mating between unrelated or distantly related individuals (see crossbreeding). Outbreeding depression may result from loss of local adaptation (see Taylor 1991 for a review of local adaptation in salmon) or from the breakup of gene combinations favored by natural selection; in the latter case, the effects of outbreeding depression are thought to depend on epistasis, or interactions between different loci (Lynch 1991).

Recovery/restoration - The reestablishment of a threatened or endangered species to a self-sustaining level in its natural ecosystem (i.e., to the point where the protective measures of the Endangered Species Act are no longer necessary).

Recovery program - A strategy for the conservation and restoration of a threatened or endangered species. An Endangered Species Act recovery plan refers to a plan prepared under Section 4(f) of the Act and approved by the Secretary, including 1) a description of site-specific management actions necessary for recovery, 2) objective, measurable criteria that can be used as a basis for removing the species from threatened or endangered status, and 3) estimates of the time and cost required to implement recovery. (For Pacific salmon, "Secretary" refers to the Secretary of Commerce.)

Self-sustaining population - A population that perpetuates itself, in the absence of (or despite) human intervention, without chronic decline, in its natural ecosystem. A self-sustaining population maintains itself at a level above the threshold for listing under the Endangered Species Act. In this document, the terms "self- sustaining" and "viable" are used interchangeably.

Species - "Any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature" (Endangered Species Act, Sec. 3 (15)). For Pacific salmon, this includes any distinct population segment that meets the qualifications of an ESU (Waples 1991a). A listed species is one determined to be threatened or endangered under the Endangered Species Act.

Stock transfer - Transfer of fish from one location to another. This includes any fish originating outside the geographical boundary of an ESU and transferred into it, any fish transferred out of an ESU's range or between areas occupied by different ESUs, or any fish transferred into vacant habitat.

Supplementation - The use of artificial propagation to reestablish or increase the abundance of naturally reproducing populations (c.f. recovery/restoration).

Take - To "harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in such conduct" (Endangered Species Act, Sec. 3(18)). See Part V for the regulation of take during artificial propagation.

### ACKNOWLEDGMENTS

### CITATIONS

Allendorf, F. W., N. Ryman, and F. M. Utter. 1987. Genetics and fishery management: Past, present, and future. In N. Ryman and F. Utter (editors), Population genetics & fishery management, p. 1-19. Univ. Washington Press, Seattle.

Bams, R. A. 1976. Survival and propensity for homing as affected by presence or absence of locally adapted paternal genes in two transplanted populations of pink salmon (Oncorhynchus gorbuscha). J. Fish. Res. Board Can. 33:2716-2725.

Becker, W. A. 1984. Manual of quantitative genetics, 4th ed. Academic Enterprises, Pullman, WA, 196 p.

Bilton, H. T., D. F. Alderdice, and J. T. Schnute. 1982. Influence of time and size at release of juvenile coho salmon (Oncorhynchus kisutch) on returns at maturity. Can. J. Fish. Aquat. Sci. 39:426-447.

Bjornn, T. C., and C. R. Steward. 1990. Concepts for a model to evaluate supplementation of natural salmon and steelhead stocks with hatchery fish. In W. H. Miller (editor), Analysis of salmon and steelhead supplementation, Part 3. Report to Bonneville Power Administration (Proj. 88-100). (Available from Bonneville Power Administration, P. O. Box 3621, Portland, OR 97208.)

Busack, C. 1990. Yakima/Klickitat production project genetic risk assessment. Unpubl. manuscr., 21 p. Genetics Unit, Washington Department of Fisheries, 115 General Administration Building, Olympia, WA 98504.

Cade, T. J. 1988. Using science and technology to reestablish species lost in nature. In E. O. Wilson and F. M. Peter (editors), Biodiversity, p. 279-288. National Academy Press, Washington, DC.

Campton, D. E., F. W. Allendorf, R. J. Behnke, F. M. Utter; M. W. Chilcote, S. A. Leider, and J. J. Loch. 1991. Reproductive success of hatchery and wild steelhead. Trans. Am. Fish. Soc. 120:816-827.

Chilcote, M. W., S. A. Leider, and J. J. Loch. 1986. Differential reproductive success of hatchery and wild summer-run steelhead under natural conditions. Trans. Am. Fish. Soc. 115:726-735.

Cuenco, M. L. 1991. Examples where supplementation has successfully resulted in increasing naturally-reproducing fish populations. Unpublished report submitted to the Endangered Species Act Administrative Record for petitioned salmon stocks, February 1991, 18 p. (Available from Environmental and Technical Services Division, NMFS, Portland, OR 97232.)

Doyle, R. W. 1983. An approach to the quantitative analysis of domestication selection in aquaculture. Aquaculture 33:167-185.

Emlen, J. M. 1991. Heterosis and outbreeding depression: A multi-locus model and an application to salmon production. Fish. Res. 12:187-212.

Endler, J. A. 1986. Natural selection in the wild. Princeton Univ. Press, Princeton, NJ, 336 p.

Falconer, D. S. 1981. Introduction to quantitative genetics, 2nd ed. Longman, London, U.K., 340 p.

Fleming, I. A., and M. R. Gross. 1992. Reproductive behavior of hatchery and wild coho salmon (Oncorhynchus kisutch): Does it differ? Aquaculture 103:101- 121.

Folmar, L. C., and W. W. Dickhoff. 1980. The parr-smolt transformation (smoltification) and seawater adaptation in salmonids: A review of selected literature. Aquaculture 21:1-37.

Franklin, I. R. 1980. Evolutionary changes in small populations. In M. E. Soul� and B. A. Wilcox (editors), Conservation biology: An evolutionary-ecological perspective, p. 135-149. Sinauer Associates, Sunderland, MA.

Gall, G. A. E. 1987. Inbreeding. In N. Ryman and F. Utter (editors), Population genetics & fishery management, p. 47-87. Univ. Washington Press, Seattle.

Gharrett, A. J., and S. M. Shirley. 1985. A genetic examination of spawning methodology in a salmon hatchery. Aquaculture 47:245-256.

Gharrett, A. J., and W. W. Smoker. 1991. Two generations of hybrids between even- and odd-year pink salmon (Oncorhynchus gorbuscha): A test for outbreeding depression? Can. J. Fish. Aquat. Sci. 48:1744-1749.

Goodman, D. 1987. The demography of chance extinction. In M. E. Soulé (editor), Viable populations for conservation, p. 11-34. Cambridge Univ. Press, Cambridge, U.K.

Goodman, M. L. 1990. Preserving the genetic diversity of salmonid stocks: A call for federal regulation of hatchery programs. Environ. Law 120:111-166.

Hard, J. J., A. C. Wertheimer, W. R. Heard, and R. M. Martin. 1985. Early male maturity in two stocks of chinook salmon (Oncorhynchus tshawytscha) transplanted to an experimental hatchery in southeastern Alaska. Aquaculture 48:351-359.

Håstein, T., and T. Lindstad. 1991. Diseases in wild and cultured salmon: Possible interaction. Aquaculture 98:277-288.

Hedrick, P. W., and P. S. Miller. 1992. Conservation genetics: Techniques and fundamentals. Ecol. Appl. 2:30-46.

Hilborn, R. 1992. Hatcheries and the future of salmon in the Northwest. Fisheries 17(1):5-8.

Hindar, K., N. Ryman, and F. Utter. 1991. Genetic effects of cultured fish on natural fish populations. Can. J. Fish. Aquat. Sci. 48:945-957.

Hoar, W. S. 1988. The physiology of smolting salmonids. In W. S. Hoar and D. J. Randall (editors), Fish physiology Vol. XIB, p. 275-343. Academic Press, New York.

Holtby, L. B., T. E. McMahon, and J. C. Scrivener. 1989. Stream temperature and inter- annual variability in the emigration timing of coho salmon (Oncorhynchus kisutch) smolts and fry and chum salmon (O. keta) fry from Carnation Creek, British Columbia. Can. J. Fish. Aquat. Sci. 46:1396-1405.

Johnson, O. W., T. A. Flagg, D. J. Maynard, G. B. Milner, and F. W. Waknitz. 1991. Status review for lower Columbia River coho salmon. U.S. Dep. Commer., NOAA Tech. Memo. NMFS F/NWC-202, 94 p.

Kaczynski, V. W., and J. F. Palmisano. 1992. A review of management and environmental factors responsible for the decline and lack of recovery of Oregon's wild anadromous salmonids. Technical report prepared for the Oregon Forest Industries Council, 292 p. (Available from Oregon Forest Industries Council, P. O. Box 12519, Salem, OR 97309.)

Lande, R. 1988. Genetics and demography in biological conservation. Science 241:1455-1460.

Lande, R., and G. F. Barrowclough. 1987. Effective population size, genetic variation, and their use in population management. In M. E. Soulé (editor), Viable populations for conservation, p. 87-123. Cambridge Univ. Press, Cambridge, U.K.

Leider, S. A., P. L. Hulett, J. J. Loch, and M. W. Chilcote. 1990. Electrophoretic comparison of the reproductive success of naturally spawning transplanted and wild steelhead trout through the returning adult stage. Aquaculture 88:239-252.

Leigh, E. G. 1981. The average lifetime of a population in a varying environment. J. Theor. Biol. 90:213-239.

Li, H. W., C. B. Schreck, C. E. Bond, and E. Rextad. 1987. Factors influencing changes in fish assemblages of Pacific Northwest streams. In W. J. Matthews and D. C. Hein (editors), Community and evolutionary ecology of North American stream fishes, p. 193-202. Univ. Oklahoma Press, Norman.

Lichatowich, J. A., and J. D. McIntyre. 1987. Use of hatcheries in the management of Pacific anadromous salmonids. Amer. Fish. Soc. Symp. 1:131-136.

Lynch, M. 1991. The genetic interpretation of inbreeding depression and outbreeding depression. Evolution 45:622-629.

Martin, R. M., and A. C. Wertheimer. 1989. Adult production of chinook salmon reared at different densities and released at two smolt sizes. Prog. Fish-Cult. 51:194-200.

Mathews, S. B. 1980. Trends in Puget Sound and Columbia River coho salmon. In W. J. McNeil and D. C. Himsworth (editors), Salmonid ecosystems of the North Pacific, p. 133-145. Oregon State Univ. Press, Corvallis.

Matthews, G. M., and R. S. Waples. 1991. Status review for Snake River spring and summer chinook salmon. U.S. Dep. Commer., NOAA Tech. Memo. NMFS F/NWC-200, 75 p.

Meffe, G. K. 1986. Conservation genetics and the management of endangered fishes. Fisheries 11(1):14-23.

Miller, W. H. (editor). 1990. Analysis of salmon and steelhead supplementation. Report to Bonneville Power Administration (Proj. 88-100). (Available from Bonneville Power Administration, P. O. Box 3621, Portland, OR 97208.)

Miller, W. H., T. C. Coley, H. L. Burge, and T. T. Kisanuki. 1990. Emphasis on unpublished and present programs. In W. H. Miller (editor), Analysis of salmon and steelhead supplementation, Part 1. Report to Bonneville Power Administration (Proj. 88-100). (Available from Bonneville Power Administration, P. O. Box 3621, Portland, OR 97208.)

Nelson, K., and M. Soulé. 1987. Genetical conservation of exploited fishes. In N. Ryman and F. Utter (editors), Population genetics & fishery management, p. 345-368. Univ. Washington Press, Seattle.

Nickelson, T. E., M. F. Solazzi, and S. L. Johnson. 1986. Use of hatchery coho salmon (Oncorhynchus kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Can. J. Fish. Aquat. Sci. 43:2443-2449.

Olla, B. L., and M. W. Davis. 1989. The role of learning and stress in predator avoidance of hatchery-reared coho salmon (Oncorhynchus kisutch) juveniles. Aquaculture 76:209-214.

Povilitis, T. 1990. Is captive breeding an appropriate strategy for endangered species conservation? Endang. Spec. Update 8:20-23.

Regional Assessment of Supplementation Project (RASP). 1992. Supplementation in the Columbia Basin. RASP Summary Report Series, Part I. Background, description, performance measures, uncertainty, and theory. Unpublished report submitted to the Bonneville Power Administration (Proj. 85-62), 39 p. (Available from Bonneville Power Administration, P.O. Box 3621, Portland, OR, 97208.)

Reisenbichler, R. R. 1988. Relation between distance transferred from natal stream and recovery rate for hatchery coho salmon. N. Am. J. Fish. Manage. 8:172- 174.

Reisenbichler, R. R., and J. D. McIntyre. 1977. Genetic differences in growth and survival of juvenile hatchery and wild steelhead trout, Salmo gairdneri. J. Fish. Res. Board Can. 34:123-128.

Riggs, L. A. 1990. Principles for genetic conservation and production quality: Results of a scientific and technical clarification and revision. Unpubl. rep. prepared for the Northwest Power Planning Council (Contract No. C90-005), 20 p. (Available from GENREC (Genetic Resource Consultants), P. O. Box 9528, Berkeley, CA 94709).

Ryman, N., and L. Laikre. 1991. Effects of supportive breeding on the genetically effective population size. Conserv. Biol. 5:325-329.

Siitonen, L., and G. A. E. Gall. 1989. Response to selection for early spawn date in rainbow trout, Salmo gairdneri. Aquaculture 78:153-161.

Simon, R. C., J. D. McIntyre, and A. R. Hemmingsen. 1986. Family size and effective population size in a hatchery stock of coho salmon (Oncorhynchus kisutch). Can. J. Fish. Aquat. Sci. 43:2434-2442.

Skaala, ., G. Dahle, K. E. J rstad, and G. N�vdal. 1990. Interactions between natural and farmed fish populations: Information from genetic markers. J. Fish. Biol. 36:449-460.

Steward, C. R., and T. C. Bjornn. 1990. Supplementation of salmon and steelhead stocks with hatchery fish: A synthesis of published literature. In W. H. Miller (editor), Analysis of salmon and steelhead supplementation, Part 2. Report to Bonneville Power Administration (Proj. 88-100). (Available from Bonneville Power Administration, P. O. Box 3621, Portland, OR 97208.)

Swain, D. P., B. E. Riddell, and C. B. Murray. 1991. Morphological differences between hatchery and wild populations of coho salmon (Oncorhynchus kisutch): Environmental versus genetic origin. Can. J. Fish. Aquat. Sci. 48:1783- 1791.

Taylor, E. B. 1991. A review of local adaptation in Salmonidae, with particular reference to Pacific and Atlantic salmon. Aquaculture 98:185-207.

Thompson, G. G. 1991. Determining minimum viable populations under the Endangered Species Act. U.S. Dep. Commer., NOAA Tech. Memo. NMFS F/NWC-198, 78 p.

Utter, F. 1981. Biological criteria for definition of species and distinct intraspecific populations of anadromous salmonids under the U.S. Endangered Species Act of 1973. Can. J. Fish. Aquat. Sci. 38:1626-1635.

Waples, R. S. 1990. Conservation genetics of Pacific salmon. II. Effective population size and the rate of loss of genetic variability. J. Hered. 81:267-276.

Waples, R. S. 1991a. Pacific salmon, Oncorhynchus spp., and the definition of "species" under the Endangered Species Act. Mar. Fish. Rev. 53(3):11-22.

Waples, R. S. 1991b. Genetic interactions between hatchery and wild salmonids: Lessons from the Pacific Northwest. Can. J. Fish. Aquat. Sci. 48 (Suppl. 1):124- 133.

Waples, R. S., G. A. Winans, F. M. Utter, and C. Mahnken. 1990. Genetic approaches to the management of Pacific salmon. Fisheries 15(5):19-25.

Washington, P. J. 1985. Survey of artificial production of anadromous salmonids in the Columbia River basin. Final report to the Bonneville Power Administration, 221 p. (Available from Bonneville Power Administration, P. O. Box 3621, Portland, OR 97208.)

Withler, R. E. 1988. Genetic consequences of fertilizing chinook salmon (Oncorhynchus tshawytscha) eggs with pooled milt. Aquaculture 68:15-25.

Table of Contents