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¹ Shanghai Ocean University, College of Marine Sciences, Shanghai, China
² National Engineering Research Center for Oceanic Fisheries, Shanghai, China
³ Ministry of Agriculture, Oceanic Fisheries Resources and Environment, Scientific Observation and Experimental Station, Shanghai, China
⁴ Shanghai Ocean University, Collaborative Innovation Center for Distant Water Fisheries, Shanghai, China DOI : 10.4194/1303-2712-v19_12_05 Viewed : 4483 - Downloaded : 3347 This study was undertaken to estimate the life history parameters of the shining catfish (Tachysurus nitidus) and small-scale yellowfin (Plagiognathops microlepis) in Lake Dianshan using length–frequency data of 4070 specimens. Both species exhibited isometric growth. The von Bertalanffy growth constants for Tachysurus nitidus were L_∞=25.15 cm, K=0.19 yr⁻¹, and t₀=-0.378 yr with a derived growth performance index of Ø′ =2.08. The corresponding estimates for Plagiognathops microlepis were L_∞=36.5 cm, K=0.10 yr⁻¹, t0= -0.40 yr and Ø′=2.125. The total mortality rate, Z, for Pelteobagrus nitidus was estimated as 1.51 yr⁻¹, with the fishing mortality, F, being calculated as 1.13 yr⁻1. The mortality estimates for Plagiognathops microlepis were Z=0.54 yr⁻¹ and F=0.33 yr⁻¹. The exploitation rates of both species (E=0.75 and E=0.61 for Tachysurus nitidusand Plagiognathops microlepis respectively) were higher than the optimum exploitation criterion (E_opt=0.5), which is indicative of over-fishing. The size-structured yield per recruit (YPR) analysis confirmed that both stocks are highly exploited, since current fishing mortality rates were higher than the biological reference points (BRPs) F_0.1 (0.16 for Tachysurus nitidus and 0.15 for Plagiognathops microlepis) and F_max (0.2 and 0.225 for Tachysurus nitidusand Plagiognathops microlepis respectively). The results further suggest that, for a sustainable management and an increase in yield, the current fishing effort for Tachysurus nitidus, be reduced to 0.2 and for Plagiognathops microlepis be decreased to 0.225. Other management action, such as gradual increase of fishing gears mesh sizes could also be considered necessary for sustainable exploitation of these stocks. Keywords : Dianshan Lake, Growth, Mortality, Tachysurus nitidus, Plagiognathops microlepis, Yield per recruit