Time filter

Source Type

Eagle, ID, United States

O'Reilly P.T.,Canadian Department of Fisheries and Oceans | Kozfkay C.C.,800 Trout Road
Reviews in Fish Biology and Fisheries | Year: 2014

In this paper, we describe the utility of microsatellite data and genetic pedigree information to guide the genetic management of two long-term conservation programs for endangered populations of salmon: Snake River Sockeye Salmon, Oncorhynchus nerka, and inner Bay of Fundy Atlantic Salmon, Salmo salar. Both programs are captive broodstock (live gene banking) programs for endangered populations of salmon. In order for these programs to be successful for recovery efforts, genetic change, including accumulation of inbreeding, loss of genetic variation, and adaptation to captivity, must be minimized. We provide an overview of each program, describe broodstock selection and pairing for spawning, and discuss how pedigree data are being used to evaluate different management practices. While there are inherent species and programmatic differences, both of these programs use widely accepted genetic conservation strategies (minimize mean kinship, reduce variance in family size, minimize inbreeding in the next generation, maintain large census and effective population size) to potentially mitigate some unintended side-effects associated with the rearing of small populations in captivity. These case studies highlight the benefits and practical limitations of applying these strategies in the genetic management of salmon, and may be used to inform other conservation programs. © 2014 Springer International Publishing Switzerland. Source

Fisch K.M.,University of California at Davis | Fisch K.M.,Institute for Conservation Research | Kozfkay C.C.,800 Trout Road | Ivy J.A.,San Diego Zoo Global | And 2 more authors.
North American Journal of Aquaculture | Year: 2015

Abstract: Artificial propagation of fish species in hatcheries has been conducted on a large scale for several decades. In recent years, however, there has been an increase in conservation hatcheries, which aim not only to produce fish for supplementing wild populations but also to preserve the genetic diversity and integrity of threatened or endangered species. Important considerations for the latter are maximizing genetic diversity and effective population size while minimizing inbreeding and adaptation to captivity. Several studies document the theoretical implementation of captive management strategies designed to achieve these goals. However, the practical application of many of these strategies to conservation hatcheries remains challenging, as the majority of the guidelines were developed for small zoo populations. The aims of this review are (1) to survey current fish conservation hatchery managers in order to assess current hatchery practices and goals; (2) to present available management strategies for conservation hatcheries that may minimize the genetic effects of artificial propagation; and (3) to present genetic management options and their trade-offs to managers developing fish conservation hatcheries. The results of the survey suggest that the majority of the responding conservation and nonconservation hatcheries use random broodstock selection and pairing techniques while valuing the importance of maintaining genetic diversity and effective population size and minimizing inbreeding. This article reviews the application of small-population management techniques to conservation hatcheries in an effort to increase their utility in recovery plans for endangered fish species. Received June 26, 2014; accepted December 21, 2014 © 2015, © American Fisheries Society 2015. Source

Campbell M.R.,800 Trout Road | Kozfkay C.C.,800 Trout Road | Copeland T.,414 East Locust Lane | Schrader W.C.,414 East Locust Lane | And 2 more authors.
Transactions of the American Fisheries Society | Year: 2012

Assessments of threatened wild Snake River steelhead Oncorhynchus mykiss have historically been limited due to a lack of stock-specific information and difficulties in field sampling efforts.We used genetic stock identification (GSI) to estimate the composition of wild adult steelhead migrating past Lower Granite Dam on the Snake River between August 24 and November 25, 2008. Further, we combined genetic data with information on sex, length, age, and run timing to examine for differences in life history or demography among stocks. In total, 1,087 samples collected at the dam were genotyped with 13 standardized steelhead microsatellite loci and a new modified Y-chromosome-specific assay that differentiates sex. A genetic baseline of 66 populations was used to complete GSI of unknown-origin samples from Lower Granite Dam. Large differences in reporting group (stock) contributions were observed for the run as a whole; the Snake River-lower Clearwater River reporting group had the largest single contribution of 36.1% (95% confidence interval [CI] = 30.2-39.7%). Other large contributions were 15.4% (12.8-18.7%) from the upper Clearwater River reporting group and 13.9% (12.5-18.7%) from the lower Salmon River reporting group. Smaller contributions came from the other six reporting groups (Imnaha River: mean = 9.5%, 95% CI = 6.8-13.6%; upper Salmon River: 9.2%, 5.1-11.3%; South Fork Clearwater River: 7.6%, 4.3-8.9%; Middle Fork Salmon River: 5.1%, 3.5-6.4%; South Fork Salmon River: 2.7%, 1.3-3.6%; Elk Creek: 0.5%, 0.0-1.2%). Significant differences in reporting group contributions were observed when samples were grouped according to length, age, and run timing differences. Of the samples analyzed, 372 (34.9%) were identified as males and 694 (65.1%) were identified as females. Our results demonstrate that the GSI methodologies applied to Snake River steelhead have the potential of providing an efficient, minimally intrusive tool for obtaining stock-specific abundance of this threatened distinct population segment. This technology can assist future viability status assessments of Snake River steelhead by contributing to refinements in population delineations, productivity calculations, and annual stock-specific estimation of life history characteristics (e.g., age structure, sex ratio, and run timing). © American Fisheries Society 2012. Source

Schill D.J.,00 South Walnut Street | Heindel J.A.,00 South Walnut Street | Campbell M.R.,800 Trout Road | Meyer K.A.,414 East Locust Lane | Mamer E.R.J.M.,414 East Locust Lane
North American Journal of Aquaculture | Year: 2016

Brook Trout Salvelinus fontinalis introduced outside of their native range often negatively impact native aquatic fauna or provide marginal fisheries and are frequently targeted for manual or piscicide removal in lakes and streams. Unfortunately, complete eradication of exotic Brook Trout populations via these methods is rarely achieved; new approaches are needed. A potential alternative is a Trojan Y Chromosome (TYC) program in which hatchery-produced genetically YY male fish would be regularly released into an undesired population over time, skewing the population towards 100% males, theoretically resulting in wild population extirpation. We developed two genetic sex markers for Brook Trout and employed juvenile sex reversal methods commonly used in commercial aquaculture to develop a YY broodstock that can produce offspring for possible future use as biological control agents. Our search for genetic sex markers proved successful, with genotypic sex determination for two assays matching the observed phenotype for 90 out of 90 individuals. In the first phase of the program, estradiol-infused feed readily feminized genetic XY males into neofemales (FXY fish) at a high rate (99.6%; n = 224). Survival of progeny from such egg-laying FXY fish averaged 88% to eye-up and 91% from eye-up to ponding, values similar to untreated Brook Trout reared at the same facility. In the second program phase, we cultured both sperm- and egg-producing supermales (YY fish), a vital step towards development of TYC technology on a large aquaculture scale. Results showed that, in the hatchery, estradiol treatment does not reduce Brook Trout growth. This study demonstrates that hatchery production of a YY Brook Trout broodstock is feasible, modest in cost (less than US$10,000), and can be completed in 4 years. Although several hurdles remain before a full-scale stocking program could occur, we believe that future work on the TYC strategy for Brook Trout is warranted. © 2016, © American Fisheries Society 2016. Source

Kozfkay C.C.,800 Trout Road | Campbell M.R.,800 Trout Road | Meyer K.A.,414 East Locust Lane | Schill D.J.,414 East Locust Lane
Transactions of the American Fisheries Society | Year: 2011

The genetic structure of redband trout Oncorhynchus mykiss gairdnerii in the upper Snake River basin was investigated at various scales using 13 microsatellite loci. The majority of the genetic variation was partitioned between streams, although differentiation among watersheds was significant. This diversity was probably historically partitioned at the watershed scale when steelhead O. mykiss (anadromous rainbow trout) were present, with the exception of small, isolated, headwater streams where there may have been only resident trout. Genetic structure appears to have been altered by a combination of factors, including habitat fragmentation and hybridization with hatchery trout. Redband trout populations in the desert and montane environments both experienced reduced gene flow, but the desert populations displayed higher degrees of genetic differentiation. There was also a significant inverse relationship between the degree of genetic differentiation and the level of allelic diversity. Interspecific hybrids with cutthroat trout O. clarkii were detected within 9% of the sampled sites, but they made up only 2% of fish and were mostly confined to one sample location. In contrast, intraspecific hybrids with coastal rainbow trout O. m. irideus were detected within 31% of the samples sites and were more than twice as likely to be found where historical records indicated that stocking of hatchery rainbow trout occurred. The inclusion of intraspecific hybridized populations altered genetic structure by creating an artificial shared ancestry among populations from different drainages and led to higher levels of genetic variation in each of the populations. The threats of fragmentation and hybridization will need to be considered in developing conservation and management policies for redband trout in Idaho. © American Fisheries Society 2011. Source

Discover hidden collaborations