Chateau, O., Wantiez, L.

Comparison of coral reef fish communities between two fished and one protected reefs in New Caledonia South Lagoon Marine Park

2005

Cybium

29

2

159-174

"The MPAs located within the New Caledonia South Lagoon Marine Park have been studied since their creation in 1989. Reef fish communities modifications within the MPAs are now well known but their interactions with unprotected areas still needs to be quantified. Prior to the study of reef fish movement patterns between MPAs and unprotected reefs, the present study was planed to compare the coral reef fish communities of two fished reefs (Crouy and Laregnere reefs) and one protected reef (Laregnere islet) within the Park. Twelve stations were sampled on each reef using underwater visual census techniques. Three point counts were completed at each station; one on the reef flat, one on the upper part of the reef slope and one on the lower part of the reef slope. Species richness, density and biomass of all edible species in the Pacific and of commercial species in New Caledonia were calculated. No significant difference occurred between reefs for edible fish and all three indices. Significant differences occurred for the commercial species, with higher values on the protected reef for all three indices. Species richness was 15% and 28% higher, density 65% and 107% higher and biomass 94% and 158% higher in the reserve than in the unprotected reefs. Significant differences occurred for the most valuable commercial families; Serranids, Siganids, commercial Acanthurids and commercial Labrids, which were also more important in the protected reef. These effects were less significant for the Scarids. Only few species, e.g., Chlorurus microrhinos, which is one of the most targeted parrotfish, have significant higher density and biomass in the protected area. Three species assemblages were identified using a Correspondence Analysis: one assemblage affected by cyclone Erica, one protected assemblage and one unprotected assemblage. A comparison with the results of a Canonical Correspondence Analysis showed that these assemblages were primarily related to reef status and secondarily to substrate characteristics. Protection measures were responsible for a modification of reef fish organisation despite a significant effect of habitat structure. The density of commercial species in fished areas near the protected area was higher than in the reserve before the protection was effective. These results and the relative stability of the protected community during 9 years support the hypothesis of significant interactions between protected reefs and nearby unprotected reefs. These results were used to plan a three years program to test fish movement patterns between these three reefs."

New Caledonia /coral reef fishes /Fish surveys /Population dynamics /Marine parks and reserves

ASFA Abstract