|FISHER, GREGORY - University Of Wisconsin|
|HELD, JAMES - University Of Wisconsin|
|MALISON, JEFFREY - University Of Wisconsin|
|HARTLEB, CHRISTOPHER - University Of Wisconsin|
|HOLMES, KENDALL - University Of Wisconsin|
Submitted to: Annual Meeting World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: 12/18/2013
Publication Date: 2/9/2014
Citation: Fisher, G.J., Held, J.A., Malison, J.A., Hartleb, C.J., Holmes, K., Shepherd, B.S. 2014. Comparative effects of constant versus fluctuating thermal regimens on yellow perch growth, feed conversion and survival [abstract]. World Aquaculture Society. Paper No. 270.
Technical Abstract: The effects of fluctuating or constant thermal regimens on growth, mortality, and feed conversion were determined for juvenile yellow perch (Perca flavescens). Yellow perch averaging 156mm total length and 43g body weight were held in replicate 288L circular tanks for 129 days under: 1) a diel thermocyclic regime of 15ºC - 21ºC; 2) a low thermostatic regime of 15ºC; or 3) a high thermostatic regime of 21ºC. Water quality parameters were monitored daily and growth parameters were measured regularly on individually-tagged animals over the experimental time-course. For all treatments average water quality parameters were within specified norms for yellow perch grow-out. Survival was 100% for the low thermostatic group (15ºC), 98% for the thermocyclic group (15ºC - 21ºC), and 85% for the high thermostatic group (21ºC). Average growth rate (AGR) calculated for body weight differed statistically (P < 0.05) among treatments, with the highest value occurring in the 15ºC - 21ºC thermocyclic group (0.36 g/day), followed by the 15ºC (0.34 g/day) and 21ºC (0.29 g/day) thermostatic groups. Similar relationships in growth rate (body weight) estimates were seen for thermal growth coefficient (TGC), but not specific growth rate (SGR). For all estimates of growth rate in body length (AGR, SGR and TGC), rates were significantly (P < 0.05) higher in the 15ºC - 21ºC thermocyclic group when compared to the thermostatic groups (15ºC and 21ºC). Apparent food conversion ratio was lowest in the 15ºC - 21ºC thermocyclic group (1.14 ± 0.01) followed by the 15ºC (1.30 ± 0.14) and 21ºC (1.41 ± 0.03), but these values were not statistically different (P = 0.10). Overall, performance (survival, growth, and feed conversion) parameters of yellow perch reared in the 15ºC - 21ºC thermocyclic group were better than values seen in perch reared under thermostatic (15ºC and 21ºC) conditions.