Genetic diversity and population structure of white-spotted charr, Salvelinus leucomaenis, in the Lake Biwa water system inferred from AFLP analysis

Abstract

The genetic variations-and the time dependence of such variations-of natural populations of the white-spotted charr ,Salvelinus leucomaenis, in the Lake Biwa water system as well as those of a hatchery-reared population were inferred from AFLP. Upon the application of principal coordinate analysis using 118 polymorphic AFLP fragments based on the Jaccard similarity index, specimens of each of six natural local populations from the inlet rivers of Lake Biwa grouped roughly together, suggesting that each local population was genetically differentiated. The hatchery-reared population was shown to be closely related to the local population in the Seri River, suggesting that the Seri River population originated from hatchery-reared charr due to extensive stocking.

Isolation and characterization of tri‐ and tetra‐repeat microsatellite loci in the white‐spotted charr Salvelinus leucomaenis (Salmonidae)

“…This is of particular relevance because of the supplemental stocking activities. The current evidence suggests accelerated rate of hybridization between wild and hatchery fish within and among subspecies (Kubota et al , ; Kikko et al , ; Sato et al , ). In addition, habitat fragmentation by artificial damming is common on Japanese rivers.…”

Interpopulation variation in egg size of fluvial white-spotted charrSalvelinus leucomaenis

“…In this paper, egg size variations were analyzed for fluvial white‐spotted charr populations in the Lake Biwa water system and its adjacent basins, which are located near the southern limit of its distribution range. Studies on the genetic structure of white‐spotted charr populations in the Lake Biwa water system suggest that fluvial white‐spotted charr form well‐defined populations, despite being geographically close to each other 5,6 …”

“…Further investigation, such as a common environment experiment, 18 is needed to demonstrate the local adaptation. The white‐spotted charr populations that were analyzed in this study were genetically differentiated due to the limited degree of gene flow among them 5,6 . Therefore, it is important to conserve each population as a significant unit.…”

“…Studies on the genetic structure of whitespotted charr populations in the Lake Biwa water system suggest that fluvial white-spotted charr form well-defined populations, despite being geographically close to each other. 5,6 Field research was conducted in seven isolated reaches where fluvial white-spotted charr occur allopatrically ( Fig. 1; Table 1).…”

Relationships among tributary length, census population size, and genetic variability of white-spotted charr, Salvelinus leucomaenis, in the Lake Biwa water system

“…Genetic variability is related to population size within and across species (Frankham 1996); however, the relationship between genetic variability and population size in the fluvial whitespotted charr populations near the southern limit of the distribution range has remained unclear (see Yamamoto et al 2004b). Therefore, from the view-point of conservation, it is indispensable to clarify whether low genetic diversity reflects mainly the recent anthropogenic disturbances such as habitat fragmentation by damming and reduced population size (Kikko et al 2007(Kikko et al , 2008b or reflects historical reductions in population size (bottlenecks) and/or population fluctuations rather than the recent anthropogenic disturbances.…”