Reproductive strategy of the invasive sharpbelly, Hemiculter leucisculus (Basilewsky 1855), in Erhai Lake, China

This study describes the reproductive strategy of the sharpbelly Hemiculter leucisculus, an invasive and dominant species in Erhai Lake in China with the goal of understanding how reproductive strategy contributes to its environmental adaptability and invasive potential. Specimens (n=3583) were collected monthly or bimonthly from July 2009 to June 2011 (min: 114-Feb, max: 883-Aug), using gill nets (inner/outer mesh=30/110mm, stretched mesh). Gonads were removed, weighed and preserved for further (histological) analyses. Oocyte size-frequency distribution was continuous and had advanced vitellogenic oocytes with postovulatory follicles present in spawning females, both suggesting that sharpbelly is a multiple spawner with adhesive eggs. Spawning extended from April to September, with the peak period from May to August. Standard lengths (SL, cm) at minimal observed maturity/L-50/L-99.9 values were 4.6/5.6/10.5 for females and 5.1/5.5/7.5cm for males, respectively. Females were over-represented (P<0.01) in SL-classes over 9cm and males completely absent from the 13 to 19cm SL-classes. Overall sex ratio was highly significantly (P<0.01) biased towards females (f=1518, o=685, f/o=2.21), however this was reversed in the spawning stock (8.3-16cm, f=58, o=142, o/f=2.45, P<0.01). Batch spawning, a long spawning period, high male investment in reproduction and adhesive eggs all represent local adaptations in reproductive strategy that, along with other environmental factors, contribute to the invasion success of sharpbelly in Erhai.