Reproductive traits of one invasive population in Lake Fuxian and two native populations in Lakes Chao and Dongting for Pseudorasbora parva were investigated to determine the variations in their reproductive strategie...Reproductive traits of one invasive population in Lake Fuxian and two native populations in Lakes Chao and Dongting for Pseudorasbora parva were investigated to determine the variations in their reproductive strategies associated with the change of environmental conditions. Compared with the two native populations,P.parva markedly experienced the protraction in their spawning time and the decrease in mortality for adult individuals in Lake Fuxian. The three populations all got their first sexual maturity at the same age,but their total lengths at maturity were quite different for those in Lake Chao were significantly lower than in Lakes Fuxian and Dongting. Additionally,in spite that no significant difference occurred in their relative fecundities for P. parva in Lakes Fuxian and Dongting,the population in Lake Chao showed the markedly higher relative fecundity than the other two populations. These results were analyzed with the variations in water temperature,nutrient status,fishing stress among the three lakes. The relative decline in fecundity for the invasive population,which conflicted with the enemy release hypothesis,was disscussed with the context of the preponderance of another invasive fish,Neosalanx taihuensis,in Lake展开更多
In recent years, fish invasion has become one of the main reasons for the decline of native fish stocks. Pseudorasbora parva is considered one of the major invasive species worldwide. The present study investigated th...In recent years, fish invasion has become one of the main reasons for the decline of native fish stocks. Pseudorasbora parva is considered one of the major invasive species worldwide. The present study investigated the fish resources of the Chabalang Wetland (Lhasa, Tibet) during diff erent seasons in 2009 and 2013. Four hundred and twelve individuals were subsampled to estimate age, growth, and feeding habit of P . parva . Furthermore, food relationships between P . parva and the native Schizothoracinae fish were also examined. The results revealed a significant shift in species composition and community structure characterized by the disappearance of native fish and outbreak of non-native fish. The percentage of nonnative P . parva in the fish collections significantly increased from 33.64% in 2009 to 64.08% in 2013. The standard length (SL) ranged from 22.00 to 78.71 mm, and their age was 1–5 a. The von Bertalanff y function was used to model the observed length-at-age data as L t =112.19(1–e^-0.1495 ( t +0.8012)) for females and as L t =123.12 (1–e^-0.1500 ( t +0.7132)) for males. The results indicated that P . parva in Tibet has lower growth and mortality rates compared with that from the native ranges. Ninety-seven prey taxa belonging to 9 prey categories were identified in the gut of 38 P . parva . P . parva can be considered a generalized and opportunistic predator, competing with the native fish, especially Schizothorax o’connori , Schizopygopsis younghusbandi younghusbandi , and Ptychobarbus dipogon , for Bacillariophyta and Chironomid larvae. This is an important reason for the decline in native fish population.展开更多
基金funded by the Key Project for Knowledge Innovation of CAS(No.KSCX1-SW-13-04)the National Key Project for Basic Research of China (No.2009CB119200)
文摘Reproductive traits of one invasive population in Lake Fuxian and two native populations in Lakes Chao and Dongting for Pseudorasbora parva were investigated to determine the variations in their reproductive strategies associated with the change of environmental conditions. Compared with the two native populations,P.parva markedly experienced the protraction in their spawning time and the decrease in mortality for adult individuals in Lake Fuxian. The three populations all got their first sexual maturity at the same age,but their total lengths at maturity were quite different for those in Lake Chao were significantly lower than in Lakes Fuxian and Dongting. Additionally,in spite that no significant difference occurred in their relative fecundities for P. parva in Lakes Fuxian and Dongting,the population in Lake Chao showed the markedly higher relative fecundity than the other two populations. These results were analyzed with the variations in water temperature,nutrient status,fishing stress among the three lakes. The relative decline in fecundity for the invasive population,which conflicted with the enemy release hypothesis,was disscussed with the context of the preponderance of another invasive fish,Neosalanx taihuensis,in Lake
基金Supported by the National Key Technology R&D Program(No.2015BAD13B06)the Finance Special Fund of Chinese Ministry of Agriculture(Fisheries Resources and Environment Survey in the Key Water Areas of Tibet)
文摘In recent years, fish invasion has become one of the main reasons for the decline of native fish stocks. Pseudorasbora parva is considered one of the major invasive species worldwide. The present study investigated the fish resources of the Chabalang Wetland (Lhasa, Tibet) during diff erent seasons in 2009 and 2013. Four hundred and twelve individuals were subsampled to estimate age, growth, and feeding habit of P . parva . Furthermore, food relationships between P . parva and the native Schizothoracinae fish were also examined. The results revealed a significant shift in species composition and community structure characterized by the disappearance of native fish and outbreak of non-native fish. The percentage of nonnative P . parva in the fish collections significantly increased from 33.64% in 2009 to 64.08% in 2013. The standard length (SL) ranged from 22.00 to 78.71 mm, and their age was 1–5 a. The von Bertalanff y function was used to model the observed length-at-age data as L t =112.19(1–e^-0.1495 ( t +0.8012)) for females and as L t =123.12 (1–e^-0.1500 ( t +0.7132)) for males. The results indicated that P . parva in Tibet has lower growth and mortality rates compared with that from the native ranges. Ninety-seven prey taxa belonging to 9 prey categories were identified in the gut of 38 P . parva . P . parva can be considered a generalized and opportunistic predator, competing with the native fish, especially Schizothorax o’connori , Schizopygopsis younghusbandi younghusbandi , and Ptychobarbus dipogon , for Bacillariophyta and Chironomid larvae. This is an important reason for the decline in native fish population.
