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, marhossain@yahoo.com)