AB 7:217-227 (2009)  -  DOI: https://doi.org/10.3354/ab00196

Larval settlement preference of a native bivalve: the influence of an invasive alga versus native substrata

Paul E. Gribben1,4,*, Jeffrey T. Wright2,5, Wayne A. O’Connor3, Peter Steinberg1

1Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
2Institute for Conservation Biology and School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
3New South Wales Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, New South Wales 2316, Australia
4Present address: Department of Environmental Sciences, University of Technology, Sydney, New South Wales 2007, Australia
5Present address: National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, The University of Tasmania, PO Box 986, Launceston, Tasmania 7250, Australia

ABSTRACT: Recruitment patterns of marine invertebrates are strongly influenced by the habitat preference of larvae as larvae can choose to settle (or not) in response to positive or negative cues. High abundances of recruits of the native infaunal bivalve Anadara trapezia occur in the invasive alga Caulerpa taxifolia compared to native habitats. Using controlled laboratory experiments, A. trapezia larval habitat preference was investigated through exposure to available native (adult A. trapezia, Zostera capricorni and sediment from unvegetated areas) and invasive (C. taxifolia and sediments from C. taxifolia) substrata that co-occur in estuaries invaded by C. taxifolia in New South Wales, Australia. When exposed to all substrata, larval settlement was significantly higher on adults compared to all other substrata except Z. capricorni. Although settlement to C. taxifolia was low, larvae did not reject it as settlement surface. In pairwise comparisons, larval settlement was always higher on adults compared to all other substrata, although differences were only significant compared to C. taxifolia and unvegetated sediments. There was no difference in settlement when larvae were exposed to Z. capricorni and C. taxifolia. When offered a single substratum, larval settlement was significantly higher on adults and Z. capricorni compared to all remaining substrata. Manipulations of shells of adults indicated that larvae may be responding positively to biofilms on the surface of shells. The data indicate that A. trapezia larvae prefer to settle on adults and, while they do not prefer C. taxifolia, they do not reject it as a settlement surface. Therefore, C. taxifolia may serve as a sink habitat for A. trapezia.


KEY WORDS: Anadara trapezia · Bivalve · Caulerpa taxifolia · Habitat choice · Habitat-forming invasive species · Invasion biology · Larval settlement


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Cite this article as: Gribben PE, Wright JT, O’Connor WA, Steinberg P (2009) Larval settlement preference of a native bivalve: the influence of an invasive alga versus native substrata. Aquat Biol 7:217-227. https://doi.org/10.3354/ab00196

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