Comparative Study On Muscle Quality And Growth Of Silver Carp And Bighead Carp In Different Types Of Reservoirs

Silver carp and Bighead carp were collected from two different types of reservoirs in Hubei province (Jinshahe Reservoir and Taoyuanhe Reservoir) during 2007. Based on conventional biological methods, the age structure, growth character, muscle nutritional quality and other biological characters of the fish were studied, then combined with the physiochemical features, biomass feed and the fish stocking in the reservoirs, In order to investigate the differences of growth and muscle nutritional quality for Silver carp and Bighead carp in different types of reservoirs, Theoretical knowledge for the reasonable utilization of fishery resource, healthy culture of reservoir fish and the sustainable development of fisheries were provided. The following are the main results:1.Scales could be used efficiently for aging the Silver carp and Bighead carp, annuli were formed mainly by close-cut in the scale. The commercial catch consisted of five age groups (age 2 to age 6) and individuals of age 3 to age 4 groups were dominant in Jinshahe reservoir. Which account for 16.03% and 68.59% respectively in Silver carp, the average body weight was 1.49 kg and 2.01 kg; while for Bighead carp occupy 69.23% and 23.08% of total capture, the average body weight was 2.17 kg and 3.11 kg; The commercial catch consisted of five age groups (age 1 to age 5) in Taoyuanhe reservoir, the individuals of age 2 to age 3 groups were dominant in Silver carp, which account for 22.45% and 69.39% respectively, the average body weight were 1.03 kg and 1.22 kg; while the age 3 to age 4 groups were dominant in Bighead carp, which occupy 75.00% and 12.31% of the total capture, the average body weight was 2.57 kg and 3.40 kg.2.The interrelation formula between the body length (L) and weight (W) of Silver carp and Bighead carp in Jinshahe reservoir were:W_H=1.0×10^-4L^2.5135and W_A=2.7×10^-5L^2.8705 respectively. Their growth could be described by von Bertalanffy equationsL_H=112.1244[1-e^{-0.1544(t+0.1371)}],W_H=14.1892[1-e^{-0.1544(t+0.1371)}]^2.5135;L_A=68.5382[1-e^{-0.396(t-0.3239)}]and W_A=5.1019[1-e^{-0.396(t-0.3239)}]^2.8705.The inflection points for the growth of Silver carp and Bighead carp were 5.8 years and 3.0 years,The growth performance indices wereΦ=7.5712 (H) ,Φ=7.5285 (A) ; The interrelation formula between the body length (L) and weight ( W ) of Silver carp and Bighead carp in Taoyuanhe reservoir were:W_H=2.5×10^-5L^2.9162and W_A=0.7×10^-5L^3.2975.von Bertalanffye quations:L_H=90.3988[1-e^{-0.1869(t-0.24997)}],W_H=12.6639[1-e⁽-0.1869(t-0.24997)]^2.9162;L_A=74.4859[1-e^{-0.3381(t-0.3649)}],W_A=10.4321[1-e^{-0.3381(t-0.3649)}]^3.2975. The inflection points for the growth of Silver carp and Bighead carp were 6.0 years and 3.9 years, The growth performance indices wereΦ=7.3315 (H) ,Φ=7.5369 (A) . 3. The crude protein (P＜0.05) and crude ash (P＞0.05) content in the muscle of Silver carp and Bighead carp in Jinshahe Reservoir were higher than that of the Taoyuanhe Reservoir, the crude fat content of Bighead carp in Jinshahe Reservoir was significantly higher than that of the Taoyuanhe Reservoir( P＜0.05),while the crude fat content of Silver carp in Jinshahe Reservoir was lower than that of the Taoyuanhe Reservoir. There were same kinds of amino acids in muscles of Silver carp and Bighead carp in two reservoirs, the total amino acids and the delicious amino acids of Silver carp in Jinshahe Reservoir were significantly higher than that of the Taoyuanhe Reservoir (P＜0.05) ,the other indexes had no significantly difference.4. According to water physiochemical features and biomass feed, the water quality of Jinshahe reservoir was good, which trophic type was meso-trophic type, while Taoyuanhe reservoir was meso-eutrophic type. It is suggested the following measures should be taken: strengthening the stocking of Silver carp in Taoyuanhe Reservoir, then the utilization of nutrients in the reservoir and output of trophic load from the water will be improved, thus more economic benefit can be achieved as well as the environment can be protected. The stocking amount of Bighead carp in Jinshahe reservoir should be reduced.