Compensating in the wild: is flexible growth the key to early juvenile survival?

Authors

  • Monica Gagliano,

  • Mark I. McCormick


M. Gagliano (monica.gagliano@jcu.edu.au) and M. I. McCormick, School of Marine and Tropical Biology, James Cook Univ., Townsville, Queensland 4811, Australia.

Abstract

We explore the mechanisms underlying the survival of a cohort of a coral reef fish (Pomacentrus amboinensis) in the first month following settlement. To investigate the extent to which growth history immediately following settlement is linked to early survival, we tagged 900 fish the morning after settlement and recaptured the survivors (n=34) 30 days later. Otolith analysis showed that individuals that were larger at settlement preferentially survived the first month in benthic habitats. We also compared these survivors with conspecifics from the same cohort that were collected at settlement and then outgrown in two experimental feeding conditions to produce fast- and slow-growing fish. Comparison of the growth histories exhibited by the survivors to those of experimental conspecifics revealed that survivors exhibited relatively slow initial growth during their first few days on the reef, followed by a period of accelerated growth. We suggest that the flexibility in growth potential of young fish allows for the occurrence of periods of rapid (and compensatory) growth that might enhance post-settlement survival by attenuating the high risk of size-selective mortality.

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