克氏原螯虾对配合饲料感知能力的研究

Ability of Red Swamp Crayfish (Procambarus clarkii) to Perceive Formulated Feed

为了解克氏原螯虾(Procambarus clarkii)对饲料感知的最大空间距离,在稻田养殖环境条件下,利用特定设计的试验设施,研究其对配合饲料的感知能力,以期为合理确定养殖水体投饵点数量和空间布局、增加饲料利用率提供科学依据。结果显示,克氏原螯虾对配合饲料感知的最大间隔距离估算为12 m;在食物间隔距离3 m和6 m捕获的雌虾与雄虾数量无显著性差异(χ^(2)>1.19,df=1,P>0.270),表明雌性与雄性对配合饲料的感知能力没有显著差异。食物感知-搜索时间与食物间隔距离呈正相关,在食物间隔距离为3 m、6 m、9 m、12 m时,食物感知-搜索的最短时间分别为(1.8±0.5) min、(5.0±1.1) min、(11.4±1.7) min、(25.2±2.4) min,最长时间分别为(3.4±0.9) h、(7.3±0.6) h、(9.0±0.8) h、(10.0±1.3) h。当食物间隔距离为3 m和12 m时,受到配合饲料刺激后分别有(68.3±1.6)%和(36.3±1.9)%的克氏原螯虾能在3 h内到达食物源。研究表明,克氏原螯虾对配合饲料的感知能力在12 m以内,食物间隔距离越小,感知-搜索时间越短。

So far,no research has been reported on the distance over which red swamp crayfish (Pro-cambarus clarkii) can perceive food,important for scientific feeding and improving the efficiency of food utilization.In this study,the ability to perceive formulated feed by red swamp crayfish was investi-gated using a test facility designed to simulate the paddy field aquaculture environment.The aim was to provide a scientific basis for determining the number and spatial arrangement of feeding points and in-crease the efficiency of feed utilization in crayfish culture.From August to October 2020,the test was carried out at a red swamp crayfish aquaculture center in Daye City,Hubei Province.Red swamp cray-fish with body length (10.5±2.78) cm and body weight (52.2±3.12) g were selected and acclimated a week before testing at a water temperature of 25-30℃,pH 8.1-8.5 and dissolved oxygen 5.2-7.5 mg/L Two paddy fields of 20 m×1 m were set as the food perceiving area and the control area (no formulated feeds),with 6 feeding points at distances of 3,6,9,12,15 and 18 m from the test crayfish release area and each trial began with 60 crayfish.The number of crayfish arriving at the feeding points was counted at 3,6,9 and 12 h for each trial to determine the maximum spacing,and the shortest and longest times to perceive food.The number of crayfish at feeding points at distances of 3,6,9 and 12 m were,respective-ly,(50.5±3.5),(47.3±2.1),(43.2±2.3) and (37.1±1.7) individuals and were 10.5,5.0,3.5 and 2.5 times the number in the control group.At distances of 15 m and 18 m,the differences in crayfish numbers between control and treatment groups were not significant.Thus,the maximum distance that red swamp crayfish can perceive food is estimated to be 12 m.No significant difference was found in the number females and males captured at a food spacing distance of 3 m or 6 m (χ^(2)>1.19,df=1,P>0.270),suggesting that there is not a significant difference in food perception between females and males.The time for perceiv-ing and foraging food was positively related to food distance.At distances of 3 m,6 m,9 m and 12 m the shortest times for perceiving and foraging food were,respectively,(1.8±0.5) min,(5.0±1.1) min(11.4±1.7) min and (25.2±2.4) min,and the longest times were (3.4±0.9) h,(7.3±0.6) h,(9.0±0.8) h and(10.0±1.3) h.At 3 m and 12 m,the percentages of crayfish reaching the food source within 3 h were(68.3±1.6)%and (36.3±1.9)%.Our results indicate that P.clarkii can perceive food within 12 m,and the shorter the distance to food,the shorter the time for perceiving and foraging the food.