Elevated size and body condition and altered feeding ecology of the grouper Cephalopholis argus in non-native habitats.

Meyer, A. L. and Dierking, Jan (2011) Elevated size and body condition and altered feeding ecology of the grouper Cephalopholis argus in non-native habitats. Open Access Marine Ecology Progress Series, 439 . pp. 203-212. DOI 10.3354/meps09338.

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Abstract

In 1956, the shallow-water grouper Cephalopholis argus was introduced from Moorea (French Polynesia), where grouper diversity (14 species) is high, to the Main Hawaiian Islands (MHI), where only 2 rare native deep-water groupers occur. In this non-native environment, the species has flourished and has become the dominant apex predator on many reefs. In the present study, a comparison of non-native populations of C. argus in the MHI with native populations in Moorea showed that mean total length (32.0 vs. 26.9 cm), mass (722 vs. 326 g), growth, and body condition were each significantly elevated in the MHI. In addition, while an ontogenetic shift towards larger prey occurred in both locations, it was faster and more consistent in Moorea than in the MHI. As a result, while small C. argus of comparable size in the 2 locations consumed similar-sized prey, large C. argus in Moorea consumed significantly longer and deeper-bodied prey than their counterparts in the MHI. This pattern was unrelated to the size distributions of available prey and may thus reflect stronger intra- and interspecific competition for small prey in Moorea. Although ecological release in a broader sense (i.e. a combination of predator release, parasite release, and competitive release) may play a role, the most direct explanation for the observed differences between C. argus in native habitats in Moorea (with many competing grouper species) and non-native habitats in the MHI (few competitors) would be competitive release (here used in the sense of benefits resulting from the reduction of interspecific competition).

Document Type: Article
Keywords: Evolutionary Ecology of Marine Fishes; Competitive release · Ecological release · Interspecific competition · Niche shift · Invasive species · Peacock hind · Main Hawaiian Islands · Moorea (French Polynesia)
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Marine Evolutionary Ecology
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.3354/meps09338
ISSN: 0171-8630
Projects: Future Ocean
Date Deposited: 02 Dec 2011 16:18
Last Modified: 21 Jun 2018 11:53
URI: http://oceanrep.geomar.de/id/eprint/12742

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