Conservation Genetics of Bull Trout in the Columbia and Klamath River Drainages
ABSTRACT We used 51 isozyme loci to determine the population genetic structure of bull trout (Salvelinus confluentus) in the Columbia and Klamath River drainages. The sampled populations have little genetic variation within and significant genetic differences among themselves. Preserving the genetic diversity of bull trout will require the continued existence of many populations throughout this region. Bull trout from the Columbia and Klamath drainages would qualify as separate “species” under the United States Endangered Species Act according to criteria established for anadromous salmonid fishes. Genotype frequencies at the four variable loci in a group of bull trout used for artificial supplementation indicate an extremely small number of effective parents. The release of such fish into the wild could have harmful effects on native fish populations. Non-native brook trout (Salvelinus fontinalis) have been introduced throughout the range of bull trout, and hybridization between these species has been reported. Protein and mitochondrial DNA genotypes collected from one stream in western Montana over an eight-year period indicate the displacement of bull trout by brook trout. This rapid displacement was accompanied by extensive production of interspecific first-generation hybrids by both reciprocal crosses.Resumen: Usamos 51 loci de enzimas para determinar la estructura poblacional genética de la trucha “bull” (Salvelinus confluentus) en las cuencas de los ríos Columbia Kalmath. Las poblaciones muestreadas tienen poca variabilidad genética interna y diferencias genéticas significativas entre ellas. La preservación de la diversidad genética de la trucha “bull” requerirá la existencia contínua de muchas poblaciones a lo largo de esta región. La trucha “bull” de las cuencas de los ríos Columbia y Klamath podrían ser catalogadas como “especies” distintas bajo el Acta de Especies en peligro de los Estados Unidos de acuerdo a los criterios establecidos para especies de salmónidos anádromos. La frecuencias genotípicas de los cuatro loci variables en un grupo de trucha “bull” usado para la suplementación artificial indica un número efectivo de padres extremadamente pequeña. La introducción en la naturaleza de tales peces podría tener efectos nocivos sobre las poblaciones nativas de peces. Truchas “brook”, no-nativas (Salvelinus fontinalis) han sido introducidas a lo largo de todo el rango de distribución de la trucha bull, y se ha reportado la hibridación entre estas especies. Genotípos de proteínas y mitocondriales recolectados en un arroyo en el oeste de Montana a lo largo de un período de ocho años indica que la trucha “bull” esta siendo desplazada por la trucha “brook”. Este rápido desplazamiento fue acompañado por la extensiva producción de híbridos inter-específicos de primera generación por los dos cruces recíprocos.
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ABSTRACT: Freshwater finfish species richness and level of endemism in East, and South and South-East Asia that included 17 nations were studied using available databases, and included nation-wise distribution, habitat types, and conservation status. The number of endemic finfish species in the region was 559, belonging to 47 families. Families Cyprinidae and Balitoridae accounted for 43.5% and 16.2% of the total number of endemic species in the region, respectively, followed by Sisoridae (25), Gobiidae (20), Melanotaeniidae (19), and Bagridae (16), and the other 41 families had at least one endemic species. Nation-wise the most number of endemic freshwater finfish species occur in India (191), followed by China (88), Indonesia (84), and Myanmar (60). In India, the endemic species accounted for 26.4% of the native freshwater fish fauna, followed by South Korea (16.9%), the Philippines, (16.3%) and Myanmar (15.7%).Statistically significant relationships discerned between the number of indigenous and endemic species richness to land area (Xla in 103 km2) of the nations in the region were, Yin = 218.961 Ln(Xla) – 843.1 (R2 = 0.735; P < 0.001) and Ye = 28.445 Ln Xla−134.47 (R2 = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Ye = 0.079Xn− 1.558 (R2 = 0.235; P < 0.05).The overall conservation status of endemic finfish in Asia was satisfactory in that only 92 species were in some state of vulnerability, of which 37 species (6.6%) are endangered or critically endangered. However, the bulk of these species (83.7%) were cave- and or lake-dwelling fish. However, nation-wise, the endemic freshwater finfish fauna of the Philippines and Sri Lanka, based on the imperilment index, were found to be in a highly vulnerable state. Among river basins, the Mekong Basin had the highest number of endemic species (31.3%). The discrepancies between databases are highlighted and the need to consolidate information among databases is discussed. It is suggested that the Mekong Basin be considered as a biodiversity hotspot, and appropriate management strategies be introduced in this regard.Diversity and Distributions 03/2007; 13(2):172 - 184. · 4.83 Impact Factor
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ABSTRACT: Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local biodiversity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on biodiversity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on biodiversity.AMBIO A Journal of the Human Environment 03/2009; 38(1):24-8. · 2.03 Impact Factor
Article: Habitat Shift of a Native Darter Etheostoma olmstedi (Teleostei: Percidae) in Sympatry with a Non-native Darter Etheostoma zonale[show abstract] [hide abstract]
ABSTRACT: Etheostoma zonale, the banded darter, was introduced to the Susquehanna River basin of Pennsylvania through an interbasin transfer, or transplantation of native fishes outside their natural range. We examined the habitat use of a darter native to the Susquehanna River drainage E. olmstedi, the tessellated darter, in sympatry and allopatry with E. zonale to determine if its habitat use was different. In the presence of E. zonale, E. olmstedi occupied significantly (P < 0.05) shallower habitats (mean depth < 27 cm) with smaller substrates (mean substrate index < 32) and slower water velocities (mean water velocity < 0.13 m s−1) than in sites without E. zonale. The habitat shift of E. olmstedi was accompanied by a compression of niche breadth. The results are consistent with the hypothesis that E. zonale excludes E. olmstedi from riffle and run habitats, restricting E. olmstedi to shallow pools and stream margins.American Midland Naturalist 01/2009; · 0.62 Impact Factor