TY - JOUR

T1 - Critical threshold size for overwintering sandeels (Ammodytes marinus)

AU - van Deurs, Mikael

AU - Hartvig, Martin

AU - Steffensen, John Fleng

PY - 2011/12/1

Y1 - 2011/12/1

N2 - Several ecologically and commercially importantfish species spend the winter in a state of minimumfeeding activity and at lower risk of predation. To enablethis overwintering behaviour, energetic reserves are generatedprior to winter to support winter metabolism.Maintenance metabolism in fish scales with body size andincreases with temperature, and the two factors togetherdetermine a critical threshold size for passive overwinteringbelow which the organism is unlikely to survivewithout feeding. This is because the energetic cost ofmetabolism exceeds maximum energy reserves. In thepresent study, we estimated the energetic cost of overwinteringfrom a bioenergetic model. The model wasparameterised using respirometry-based measurements ofstandard metabolic rate in buried A. tobianus (a close relativeto A. marinus) at temperatures from 5.3 to 18.3C andvalidated with two independent long-term overwinteringexperiments. Maximum attainable energy reserves wereestimated from published data on A. marinus in the NorthSea. The critical threshold size in terms of length (Lth) forA. marinus in the North Sea was estimated to be 9.5 cm.We then investigated two general predictions: (1) Fishsmaller than Lth display winter feeding activity, and (2) sizeat maturation of iteroparous species is larger than Lth toensure sufficient energy reserves to accommodate both themetabolic cost of passive overwintering and reproductiveinvestments. Both predictions were found to be consistentwith data on size at maturation and total body energy inDecember and February.

AB - Several ecologically and commercially importantfish species spend the winter in a state of minimumfeeding activity and at lower risk of predation. To enablethis overwintering behaviour, energetic reserves are generatedprior to winter to support winter metabolism.Maintenance metabolism in fish scales with body size andincreases with temperature, and the two factors togetherdetermine a critical threshold size for passive overwinteringbelow which the organism is unlikely to survivewithout feeding. This is because the energetic cost ofmetabolism exceeds maximum energy reserves. In thepresent study, we estimated the energetic cost of overwinteringfrom a bioenergetic model. The model wasparameterised using respirometry-based measurements ofstandard metabolic rate in buried A. tobianus (a close relativeto A. marinus) at temperatures from 5.3 to 18.3C andvalidated with two independent long-term overwinteringexperiments. Maximum attainable energy reserves wereestimated from published data on A. marinus in the NorthSea. The critical threshold size in terms of length (Lth) forA. marinus in the North Sea was estimated to be 9.5 cm.We then investigated two general predictions: (1) Fishsmaller than Lth display winter feeding activity, and (2) sizeat maturation of iteroparous species is larger than Lth toensure sufficient energy reserves to accommodate both themetabolic cost of passive overwintering and reproductiveinvestments. Both predictions were found to be consistentwith data on size at maturation and total body energy inDecember and February.

U2 - 10.1007/s00227-011-1774-8

DO - 10.1007/s00227-011-1774-8

M3 - Journal article

VL - 158

SP - 2755

EP - 2764

JO - Marine Biology

JF - Marine Biology

SN - 0025-3162

IS - 12

ER -