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Colony regeneration following damage and size-dependent mortality in the Australian ascidian Podoclavella moluccensis Sluiter

Journal Article


Abstract


  • Among colonial marine invertebrates, early phases of the life history might be expected to be more susceptible to attacks by predators. By inflicting damage to animals and using caging and tethering manipulations, I examine the potential and real impact of predators on colonies and single-zooid recruits of the subtidal ascidian Podoclavella moluccensis Sluiter. Juvenile colonies (< 3 months old) disappeared within 4 wk of the experimental removal of zooids and tunic, indicating that they were highly susceptible to predators. Colonies of 11 months age, on the other hand, regenerated rapidly; within 36 days colony size and zooid height were indistinguishable from those of undamaged controls. Caging experiments revealed that the impact of predators was variable over small spatial scales and that the ability to distinguish their impact was dependent on the initial density of recruits; the removal of recruits at high densities by predators was compensated by the growth of remaining colonies. Crabs were identified as the predators responsible for the removal of ascidian recruits. The tethering of crabs above recruits indicated that damage could be attributed to trampling by these crustaceans. This study indicates that predators may not directly influence the distribution and abundance of adult colonies of Podoclavella, but act indirectly by killing recruits and juvenile colonies. © 1988.

Publication Date


  • 1988

Citation


  • Davis, A. R. (1988). Colony regeneration following damage and size-dependent mortality in the Australian ascidian Podoclavella moluccensis Sluiter. Journal of Experimental Marine Biology and Ecology, 123(3), 269-285. doi:10.1016/0022-0981(88)90047-0

Scopus Eid


  • 2-s2.0-0024256256

Start Page


  • 269

End Page


  • 285

Volume


  • 123

Issue


  • 3

Abstract


  • Among colonial marine invertebrates, early phases of the life history might be expected to be more susceptible to attacks by predators. By inflicting damage to animals and using caging and tethering manipulations, I examine the potential and real impact of predators on colonies and single-zooid recruits of the subtidal ascidian Podoclavella moluccensis Sluiter. Juvenile colonies (< 3 months old) disappeared within 4 wk of the experimental removal of zooids and tunic, indicating that they were highly susceptible to predators. Colonies of 11 months age, on the other hand, regenerated rapidly; within 36 days colony size and zooid height were indistinguishable from those of undamaged controls. Caging experiments revealed that the impact of predators was variable over small spatial scales and that the ability to distinguish their impact was dependent on the initial density of recruits; the removal of recruits at high densities by predators was compensated by the growth of remaining colonies. Crabs were identified as the predators responsible for the removal of ascidian recruits. The tethering of crabs above recruits indicated that damage could be attributed to trampling by these crustaceans. This study indicates that predators may not directly influence the distribution and abundance of adult colonies of Podoclavella, but act indirectly by killing recruits and juvenile colonies. © 1988.

Publication Date


  • 1988

Citation


  • Davis, A. R. (1988). Colony regeneration following damage and size-dependent mortality in the Australian ascidian Podoclavella moluccensis Sluiter. Journal of Experimental Marine Biology and Ecology, 123(3), 269-285. doi:10.1016/0022-0981(88)90047-0

Scopus Eid


  • 2-s2.0-0024256256

Start Page


  • 269

End Page


  • 285

Volume


  • 123

Issue


  • 3