Peroo

Aquaculture Research, 2009, 1^8

doi:10.1111/j.1365-2109.2009.02316.x

Size-related oxygen consumption and ammonia excretion of Eurasian perch (Perca fluviatilis L.) reared in a recirculating system
› Vlastimil Stejskal, Jan Kouril, Olga Valentova, Jitka Hamackova & Tomas Policar Ł Ł › Ł Ł ›
í ¤ Research Institute of Fish Culture and Hydrobiology Vodnany, University of South Bohemia CeskeBudejovice,Vodnany, › › › Czech Republic
í ¤ Correspondence: V Stejskal, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia Ceske Budejovice, › Vodnany, Zatis› |¤ 728/II, 389 25 Vodnany, Czech Republic. E-mail: stejskal@vurh.jcu.cz › › Ł

Abstract
Oxygen consumption (OC) and ammonia excretion rates (AE) of perch were measured under commercial-like conditions(temperature 23.3 1C) in both fed (F) and feed-deprived groups (D). Measurements were taken in triplicate in six sized batches of perch ranging from 44.8 to 336.2 g. The mean daily OC was 288.3^180.6 mg O2 kg À 1 h À 1 for group F ¢sh ranging in size from 44.8 to 279.4 g body weight. The mean daily AE expressed as total ammonia nitrogen (TAN) was 13.8^5.2 mg TAN kg À 1 h À 1 in the same groups. Dailypeaks of OC in group F perch were observed 6 h after the onset of feeding for each size group with relatively stable values up to the end of feeding. Peaks of daily AE in group F perch were observed 10 h after the onset of feeding in each size group, with a rapid decrease up to 16 h after onset. In group D, OC was 181.1^110.5 mg O2 kg À 1 h À 1 in the weight range 57.9^336.2 g. The daily mean AEwas 1.7^0.5 TAN kg À 1 h À 1 in this group. No dramatic peaks of OC and AE were observed in group D perch.

Keywords: water quality, percids, perch culture, metabolic rate

Introduction The Eurasian perch (Perca £uviatilis L.) is a cold freshwater ¢sh species considered to be a new candidate for aquaculture. The contemporary traditional pond method has been used for the production ofcommercial-sized perch in polyculture with common carp ¤ Cyprinus carpio L. (Melard, Kestemont & Grignard 1996). The life cycle of perch can be arti¢cially con-

trolled, including the production of eggs and larvae (Migaud, Mandiki, Gardeur, Kestemont, Bromage & Fontaine 2003), larvae weaning and ongrowing to ¤ ¤ market size (Kestemont, Melard, Fiogbe, Vlavonou & Masson 1996). Zootechnical aspects ofperch culture ¤ ¤ have been studied (Melard et al. 1996; Fiogbe & Keste˛ ˛ mont 2003; ZakesŁ, Demska-ZakesŁ & Kata 2003), and nutritional requirements have been determined ¤ ¤ (Fiogbe, Kestemont, Melard & Micha1996; Kestemont, ¤ lard, Fontaine & Brown 2001). Vandeloise, Me Presently, perch culture mainly takes place in recirculation systems. However, the high investment and running costs of suchsystems require e⁄cient utilization of recirculating water. Production in these systems is pro¢table only when the stocking density ¤ of ongrowing perch is high (Melard et al. 1996), and requires data on the critical levels of oxygen and ammonia. A low concentration of oxygen or a high concentration of ammonia induces signi¢cant stress, leading to pathology and reduced growth rates, and, in severecases, death (Evans, Shoemaker & Klesius 2003; Pinto, Aragao, Soares, Dinis & Conceicao ° ì ì 2007). Therefore, perch oxygen requirements can help in farm design, management and planning to optimize the system. Data on oxygen consumption (OC) will allow de¢ning appropriate stocking densities, water £ow and arti¢cial re-oxygenation requirements. The ammonia excretion rate (AE), a major factor inwaste accumulation, is another factor that limits ¢sh production in such systems (Fernandez & Tanner 2008). Understanding the relationships among ¢sh size, biomass, feeding level and ¢sh metabolism (AE and OC) is important for determining the carrying capacity of the culture system as well as the size and e⁄cacy of the biological ¢lter.

r 2009 The Authors Journal Compilation r 2009 Blackwell...