Effect of development rate on the swimming, escape responses, and morphology of yolk-sac stage larval American plaice, Hippoglossoides platessoides
T. D. Shepherd, K. E. Costain, M. K. Litvak-2000
Marine Biology, 137(4): 737-745
Abstract:
To examine the impact of development rate on swimming
performance, escape response, and morphology, yolk-sac larvae of American
plaice (Hippoglossoides platessoides, Fabricius) were reared at two
temperatures (5 and 10 °C). Videomicroscopy and silhouette collimation
videography were used to examine swimming, escape behaviour, and morphology
(standard length, finfold area, and yolk-sac area) of individual larvae.
Larvae were examined from 0 d post hatch (dph) to 14 dph for the 5 °C
treatment group and from 0 to 6 dph for the 10 °C treatment group (3 August
to 17 August 1996). Since larvae were not fed, yolk-sac reserves were
essentially exhausted by 14 and 6 dph for the 5 and 10 °C treatment groups,
respectively. To control for the effect of testing temperature on behaviour,
larvae from each temperature treatment were tested at both 5 and 10 °C.
Testing temperature had an effect on some swimming parameters but not on
escape response. Swimming performance, escape response, and morphology
varied with age, while only morphology and escape response varied with
development rate. Morphology and swimming performance, and morphology and
escape response were found to be correlated as determined by canonical
correlation. This study suggests that both types of swimming behaviours
should be examined when developing models of the impacts of predation on the
early life history of larval fish.
(Centre for Coastal Studies and Aquaculture,
Department of Biology, University of New Brunswick, P.O. Box 5050, Saint
John, New Brunswick, E2L 4L5, Canada, Tel.: +1-506-6485508; Fax:
+1-506-6485811, e-mail of M.K. Litvak: litvak@unbsj.ca)