Predator-prey
interaction between hatchery-reared Japanese flounder juvenile, Paralichthys
olivaceus, and sandy shore crab, Matuta lunaris: daily
rhythms, anti-predator conditioning and starvation
M.A.R.
Hossain, M. Tanaka, R. Masuda-2002
Journal
of Experimental Marine Biology and Ecology, 267(1): 1-14
Abstract:
Predator-prey
interaction between sandy shore crab, Matuta lunaris (Forskål,
1775), and juvenile Japanese flounder, Paralichthys olivaceus (Temminck
et Schlegel), was investigated under controlled laboratory conditions.
Possibility of training and conditioning hatchery-reared flounder to avoid
predators was also examined. Crabs took over 75% of their daily ration at
night when they were given access to prey 24 h a day. Large (64.8±5.4 g)-
and medium (30.68±3.33 g)-sized crabs ate ca. 5.5±1.45 and 3.9±1.99
individuals of flounder (TL=4.96±0.23 cm) a day, respectively. When
flounder juveniles that have experienced predation pressure by crabs
encountered predators again, they exhibited better survival compared to the
naive fish. Flounder juveniles were also conditioned either using small and,
thus, benign predators, or large crabs over fence. The conditioned fish with
either method were better able to avoid capture by crabs than naive fish,
revealing that learning process should play an important role in their
predator avoidance. Anti-predator performance was also compared between
starved and fed flounder juveniles. Fed fish were rarely eaten by predators
after 3 h of exposure, whereas starved fish continued to be eaten. Our
results suggest that stock-enhancement program of Japanese flounder can be
improved by applying proper feeding protocol and conditioning to avoid
predators prior to release. Present research supports the idea that
behavioural and ecological consideration for the target species is
indispensable for the success of stock enhancement.
(Laboratory
of Marine Stock-Enhancement Biology, Division of Applied Biosciences,
Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan,
Tel.: +81-75-753-6222; fax: +81-75-753-6229, e-mail: marhossain@yahoo.com)