Intraspecific growth variation among rainbow trout and brook trout: Impact of initial body weight and feeding level

Publication: Research - peer-reviewJournal article – Annual report year: 2010

Standard

Intraspecific growth variation among rainbow trout and brook trout: Impact of initial body weight and feeding level. / Rasmussen, Richard Skøtt; Ostenfeld, T.

In: Aquaculture International, Vol. 18, No. 5, 2010, p. 933-941.

Publication: Research - peer-reviewJournal article – Annual report year: 2010

Harvard

APA

CBE

MLA

Vancouver

Author

Rasmussen, Richard Skøtt; Ostenfeld, T. / Intraspecific growth variation among rainbow trout and brook trout: Impact of initial body weight and feeding level.

In: Aquaculture International, Vol. 18, No. 5, 2010, p. 933-941.

Publication: Research - peer-reviewJournal article – Annual report year: 2010

Bibtex

@article{6905a95938414c37a39bc88559b08b19,
title = "Intraspecific growth variation among rainbow trout and brook trout: Impact of initial body weight and feeding level",
keywords = "Rearing, Coefficient of variation, Condition factor, Size variation",
publisher = "Springer Netherlands",
author = "Rasmussen, {Richard Skøtt} and T. Ostenfeld",
year = "2010",
doi = "10.1007/s10499-009-9313-z",
volume = "18",
number = "5",
pages = "933--941",
journal = "Aquaculture International",
issn = "0967-6120",

}

RIS

TY - JOUR

T1 - Intraspecific growth variation among rainbow trout and brook trout: Impact of initial body weight and feeding level

A1 - Rasmussen,Richard Skøtt

A1 - Ostenfeld,T.

AU - Rasmussen,Richard Skøtt

AU - Ostenfeld,T.

PB - Springer Netherlands

PY - 2010

Y1 - 2010

N2 - This study describes growth variation within groups of salmonids and the relation to initial fish weights and feeding levels. PIT-tagged rainbow trout (RT) and brook trout (BT) of start weight 120–170 g were reared in separate tanks for 9 weeks. Both species were fed each day either a high ration close to satiation (H) or half of this ration (L). Four experimental groups (RT-H, RT-L, BT-H, BT-L) were studied with regard to their propensity to increase weight in accord with their initial weight. The slope of the regression line between initial weights (g) and weight increases for individuals in each tank in each period was applied as indicator for this propensity (termed “slope”). All calculated slopes in the experiment were positive which indicates the general ability of weighty fish to gain more weight than smaller individuals. The average slope during all 9 weeks was 2–4 times higher for RT-L (5.91) than for all other groups (RT-H: 1.50, P <0.01; BT-H: 1.76, P <0.01 and BT-L: 2.88, P <0.05), indicating the particular propensity of large RT to gain weight when feed was restricted. Overall, ration level had large impact on slopes (H: 1.63, L: 4.39, P <0.01), while this was not the case for species (RT: 3.71, BT: 2.32, P > 0.05). The magnitude of slopes decreased over time (weeks 0–3:4.27, weeks 3–6:3.02 and weeks 6–9:1.74, P <0.05). The observed differences in weight gains between experimental groups were reflected in differences in coefficients of variations (CVs) for body growth. RT had larger body weight (BW) CVs compared to BT (0.257 vs. 0.206, P <0.01) indicating more uneven feed share among RT than among BT in general. RT-L had significantly higher BW CVs than all other groups (0.300 vs. 0.184–0.229, P <0.01). The observed differences in weight gains enhance size variations in terms of higher CVs, and this may have implications for feeding tactics in aquaculture where large size variations in groups may be disadvantageous to fish farmers.

AB - This study describes growth variation within groups of salmonids and the relation to initial fish weights and feeding levels. PIT-tagged rainbow trout (RT) and brook trout (BT) of start weight 120–170 g were reared in separate tanks for 9 weeks. Both species were fed each day either a high ration close to satiation (H) or half of this ration (L). Four experimental groups (RT-H, RT-L, BT-H, BT-L) were studied with regard to their propensity to increase weight in accord with their initial weight. The slope of the regression line between initial weights (g) and weight increases for individuals in each tank in each period was applied as indicator for this propensity (termed “slope”). All calculated slopes in the experiment were positive which indicates the general ability of weighty fish to gain more weight than smaller individuals. The average slope during all 9 weeks was 2–4 times higher for RT-L (5.91) than for all other groups (RT-H: 1.50, P <0.01; BT-H: 1.76, P <0.01 and BT-L: 2.88, P <0.05), indicating the particular propensity of large RT to gain weight when feed was restricted. Overall, ration level had large impact on slopes (H: 1.63, L: 4.39, P <0.01), while this was not the case for species (RT: 3.71, BT: 2.32, P > 0.05). The magnitude of slopes decreased over time (weeks 0–3:4.27, weeks 3–6:3.02 and weeks 6–9:1.74, P <0.05). The observed differences in weight gains between experimental groups were reflected in differences in coefficients of variations (CVs) for body growth. RT had larger body weight (BW) CVs compared to BT (0.257 vs. 0.206, P <0.01) indicating more uneven feed share among RT than among BT in general. RT-L had significantly higher BW CVs than all other groups (0.300 vs. 0.184–0.229, P <0.01). The observed differences in weight gains enhance size variations in terms of higher CVs, and this may have implications for feeding tactics in aquaculture where large size variations in groups may be disadvantageous to fish farmers.

KW - Rearing

KW - Coefficient of variation

KW - Condition factor

KW - Size variation

U2 - 10.1007/s10499-009-9313-z

DO - 10.1007/s10499-009-9313-z

JO - Aquaculture International

JF - Aquaculture International

SN - 0967-6120

IS - 5

VL - 18

SP - 933

EP - 941

ER -