Reproductive characteristics of Ancherythroculter nigrocauda, an endemic fish in the upper Yangtze River, China

Abstract

Knowledge on the reproductive biology of fishes is critical for understanding a species' life history and devising appropriate management strategies. Anthropogenic forces, such as damming and overfishing, threaten fishes endemic to the upper Yangtze River. We conducted a study on the reproductive biology of an endemic species, Ancherythroculter nigrocauda in order to provide information on the life history of this species and to assist in its conservation. From July 2011 to June 2012, a total of 417 fishes were captured via monthly sampling by fishermen in the Longxi River, a tributary in the upper Yangtze River. Although the female-male ratio was 1:1.03, females were predominantly larger in body size. Gonad somatic indices and oocyte diameter distribution showed that the spawning period of A. nigrocauda in the Longxi River ranged from April to August, with the peak in April. Body length at 50 % sexual maturity of A. nigrocauda was estimated to be 125 and 106 mm for females and males, respectively. Absolute fecundity of A. nigrocauda varied between 11,300 and 504,630 eggs, with the mean of 162,377 eggs. In conclusion, A. nigrocauda mature early, spawn once, and are highly fecund, all of which are consistent with an r-selected life history. It is recommended that a moratorium on fishing this species be enacted and the culture of this species be continued.

Genetic diversity and population structure of a cyprinid fish ( Ancherythroculter nigrocauda ) in a highly fragmented river

“…Therefore, although the adhesive eggs of A. nigrocauda can't drift downstream, the larvae can drift downstream passively in the flooding season. In addition, A. nigrocauda reproduces large number of offspring (absolute fecundity varied between 11,300 and 504,630 eggs, with the mean value of 162,377) from April to August during the flooding season (Liu et al, ), making its larvae drift to the downstream from the Yulong Lake largely and easily. Eleven pairs of half‐sibling relationships between the two populations confirmed the presence of individual movement and gene flow between them, which could weaken the genetic differentiation caused by the blocking effect of dams.…”

“…This species is a resident fish and reproduces adhesive eggs from April to August. Its absolute fecundity varied from 11,300 to 504,630 eggs, with the mean of 162,377 eggs (Liu et al, ). It is also an important economic fish and aquaculture species in China.…”

“…Eight dams have been constructed on the Longxi river since 1920s (Figure ; Table ; Wang, ) and fragmented the populations of A. nigrocauda. There were some studies suggested that the growth and reproduction of the populations of A. nigrocauda in Longxi River have been adversely influenced, it might be related to damming (Liu, ; Liu et al, ). However, impacts of dams on the genetic diversity and population structure of A. nigrocauda in Longxi River have been little investigated.…”

Reproductive Traits of Brown Trout in Two Contrasting Streams of Southeast Minnesota

“…We defined length-and age-at-maturity as the length or age at which 50% of the individuals in a population were mature (Liu et al 2013). To estimate length-and age-at-maturity, we scored maturation as 0 for immature Brown Trout and 1 for mature individuals.…”

“…To estimate length-and age-at-maturity, we scored maturation as 0 for immature Brown Trout and 1 for mature individuals. We then used logistic regression with either length or age as our dependent variable to estimate the length or age at which 50% of the individuals became mature (Liu et al 2013;Hoxmeier et al 2015). Both sexes were analyzed independently for each study site, from which we generated 95% confidence intervals of the predicted probability of being mature (SAS 2009).…”