9698 - Laserfiche WebLink

Home Browse Search

()[)O ~ ~ (\V1 + \}J hi-\-L-. . , I North American Journal of Fisheries Management 26:916-920. 2006 @ Copyright by the American Fisheries Society 2006 DOl: 10.1577 /M05-176.1 Qro98 [Article] these popu been mas anthrOpOgl mended IT Green, ant the Green separate 11 In this (mtDNA) three stock we also specimens the stocki determinin be maintai Mitochondrial DNA Variation in the Endangered Colorado Pikeminnow: A Comparison among Hatchery Stocks and Historic Specimens KIMBERLY BORLEY AND MATIHEW M. WIillE* Department of Biological Sciences, Ohio University, Athens, Ohio 45701, USA Abstract.- The Colorado pikeminnow Ptychocheilus lucius is a federally endangered species restricted to the Colorado River. Dexter National Fish Hatchery and Technology Center, Dexter, New Mexico, maintains' three separate captive stocks of the Colorado pikeminnow: 1974YC (Yampa River), 1981YC (Green- Colorado rivers), and 1991YC (Colorado River). We surveyed mitochondrial DNA diversity in these three stocks (879 base pairs [bp]; ND-4L and ND4 genes; N = 30) and in museum specimens collected from 1890 to 1976 (450 bp; ND4; N= 11). All individuals had the same haplotype except for a I-bp variant detected in 2 of the 12 fish from 1981 yc. The low variation is postulated to be the result ofa post-Pleistocene bottleneck in the wild and small sizes of the hatchery founder populations. Captive propagation and release have become important components of the management and recovery of endangered fishes. These propagation efforts are often designed to augment natural populations and to protect or enhance existing genetic diversity (Allendorf and Ryman 1987). Where multiple hatchery stocks are maintained as evolutionarily significant units (ESUs) or management units (MUs; Moritz 1994), the goal is to ensure that the genetic diversity is protected and that stocks are available to supplement different populations. When multiple stocks are maintained, the underlying assumption is that these separate stocks capture different portions of the overall genetic diversity and that maintaining them is important to the continued survival and evolutionary potential of the species. The Colorado pikeminnow Ptychocheilus /ucius is a federally protected endangered species endemic to the Colorado River basin. This species was once abundant and widespread throughout the drainage (Miller 1961) and now inhabits only the upper part of the basin (Osmundson and BumhaDl 1998). The largest popula- tions are found in the YaDlpa and Green rivers (Tyus 1991), while smaller populations are found in the White, upper Colorado (Osmundson and BumhaDl 1998), Gunnison, and San Juan rivers (Platania et al. 1991; USFWS 2002). The Green, YaDlpa, upper Colorado, Gunnison, and San Juan rivers are known sites of natural reproduction (USFWS 2002). Long- distance spawning migrations (potamodromy) have been observed (Tyus and McAda 1984; Tyus 1985). . Stocking of Colorado pikeminnow began in 1974 Ii i * Corresponding author: whitem@ohio.ediJ Received October 21,2005; accepted May 15, 2006 Published online November 20, 2006 :oj jj d Li when the U.S. Fish and Wildlife Service's (USFWS) Dexter National Fish Hatchery and Technology Center (DNFHTC) , Dexter, New Mexico, developed the broodstock for the 1974 year-class (YaDlpa River DX-F1; 74YC) with eight individuals collected from the Yampa River in 1973. The 1981 year-class (Colorado-Green DX-F1; 81~C) was established from 13 fish collected from the Green and Colorado rivers in 1978 and 1979. The 1991 year-class (Colorado DX-Fo; 91 YC) was derived from 10 fish collected from the Colorado River between 1987 and 1990 (WilliaDlson et al. 1998; Morizot et al. 2002; J. H. WilliaDlson, DNFHTC, personal communication). Young produced in the hatchery have been used to supplement wild populations. Between 1980 and 1984, approximately 130,000 hatchery individuals from 74YC were introduced into the upper Colorado River (Morizot et al. 2002). WilliaDlson et al. (1998) reported 14 introductions of Colorado pikeminnow for reestab- lishment and supplementation. All fish stocked through the early 1990s were derived from the 74YC brood- stock (Morizot et al. 2002). Over 300,000 hatchery fish from 81 YC (Colorado-Green rivers) were introduced into the San Juan River between 1996 and 1998. Since 2000, approximately 2,480 fish from 91YC have been stocked into the upper Colorado River and an additional 2,248 have been stocked into tlie Gunnison River (T. Czapla, USFWS, personal communication). Ammerman and Morizot (1989) compared allozyme variation in 81 YC and 74YC and concluded that the hatchery populations were genetically similar to wild populations in the Colorado and Green rivers. Morizot et al. (2002) used allozymes to eXaDline variation aDlong 74YC, 81 YC, and saDlples of wild-caught fish. They concluded that Colorado pikeminnow constitute a single panmictic population and that divergence aDlong Tissue , obtained fi 91YC (N= obtained fl Green (N = 2), and up 1974) or j stocks (Fig Extractl DNA.- Th tissues wit! Valencia, l museum Sl protocol in mtDNA fra ND-4L NA with the pri (Bielawski SaDlples fr primers wi (PCR) proc primers am ND4LB C aDlplified 1 aDlplified v were in 2, [Bioline U~ MgClz, 0.: [dNTP] , 0.: polymerasl Thermal cy for 30 s, ant was accoml sequencing chusetts). F JlL BigDy' sequencing 916