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Valerio Tettamanti - One of the best experts on this subject based on the ideXlab platform.
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visual system development of the spotted unicornfish naso brevirostris Acanthuridae
The Journal of Experimental Biology, 2019Co-Authors: Valerio Tettamanti, Fanny De Busserolles, David Lecchini, Justin Marshall, Fabio CortesiAbstract:Ontogenetic changes of the visual system are often correlated with shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This habitat transition frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to mainly zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris changes primarily during the transition from the larval to the juvenile stage, with only minor modifications thereafter. Similarly, visual gene (opsin) expression based on RNA sequencing, although qualitatively similar between stages (all fish mainly expressed the same three cone opsins; SWS2B, RH2B, RH2A), also showed the biggest quantitative difference when transitioning from larvae to juveniles. The juvenile stage in particular seems mismatched with its reef-associated ecology, which may be due to this stage only lasting a fraction of the lifespan of these fish. Hence, the visual ontogeny found in N. brevirostris is very different from the progressive changes found in other reef fishes, calling for a thorough analysis of visual system development of the reef fish community.
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neoteny in visual system development of the spotted unicornfish naso brevirostris Acanthuridae
bioRxiv, 2019Co-Authors: Valerio Tettamanti, Fanny De Busserolles, David Lecchini, Justin Marshall, Fabio CortesiAbstract:Abstract Ontogenetic changes of the visual system are often correlated to shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This transition of habitat frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris do not change with the habitat or the feeding habits of each developmental stage. Instead, fishes showed a neotenic development with a slight change from larval to juvenile stages and not many modifications thereafter. Visual gene expression based on RNA sequencing mirrored this pattern; independent of stage, fishes mainly expressed three cone opsin genes (SWS2B, RH2B, RH2A), with a quantitative difference in the expression of the green opsin genes (RH2A and RH2B) when transitioning from larvae to juveniles. Hence, contrary to the ontogenetic changes found in many animals, the visual system is fixed early on in N. brevirostris development calling for a thorough analysis of visual system development of the reef fish community.
David R. Bellwood - One of the best experts on this subject based on the ideXlab platform.
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an evaluation of a double tailed deformity in a coral reef surgeonfish acanthurus nigrofuscus Acanthuridae using micro computed tomography
Journal of Fish Biology, 2018Co-Authors: Christopher H R Goatley, Stephen Wroe, Sterling B Tebbett, David R. BellwoodAbstract:X-ray micro-computed tomography scans were used to examine the caudal-fin structure of an unusual double-tailed deformity in an adult brown surgeonfish Acanthurus nigrofuscus from the Great Barrier Reef. In both this case and in a similar double-tailed deformity in a juvenile Tomini surgeonfish Ctenochaetus tominiensis from the Philippines, the caudal fin was duplicated along the dorsoventral axis. Detailed examination of the A. nigrofuscus specimen revealed that the deformity was associated with duplication and reflection of the hypural plates and the posterior vertebrae, yet the fish survived to adulthood, indicating that the effects of duplication on survival may be limited.
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exploring the nature of ecological specialization in a coral reef fish community morphology diet and foraging microhabitat use
Proceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Simon J Brandl, William D Robbins, David R. BellwoodAbstract:Patterns of ecological specialization offer invaluable information about ecosystems. Yet, specialization is rarely quantified across several ecological niche axes and variables beyond the link between morphological and dietary specialization have received little attention. Here, we provide a quantitative evaluation of ecological specialization in a coral reef fish assemblage (f. Acanthuridae) along one fundamental and two realized niche axes. Specifically, we examined ecological specialization in 10 surgeonfish species with regards to morphology and two realized niche axes associated with diet and foraging microhabitat utilization using a recently developed multidimensional framework. We then investigated the potential relationships between morphological and behavioural specialization. These relationships differed markedly from the traditional ecomorphological paradigm. While morphological specialization showed no relationship with dietary specialization, it exhibited a strong relationship with foraging microhabitat specialization. However, this relationship was inverted: species with specialized morphologies were microhabitat generalists, whereas generalized morphotypes were microhabitat specialists. Interestingly, this mirrors relationships found in plant–pollinator communities and may also be applicable to other ecosystems, highlighting the potential importance of including niche axes beyond dietary specialization into ecomorphological frameworks. On coral reefs, it appears that morphotypes commonly perceived as most generalized may, in fact, be specialized in exploiting flat and easily accessible microhabitats.
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Morphology, sociality, and ecology: can morphology predict pairing behavior in coral reef fishes?
Coral Reefs, 2013Co-Authors: S. J. Brandl, David R. BellwoodAbstract:Morphology can contain valuable information about the ecological performance of reef fishes, but it has rarely been used in combination with social traits. Social behavior is known to influence the ecological role of fishes; however, the ecological basis for pairing in reef fishes is not well understood. Field observations of 2,753 individuals, in 47 species in six families of biting reef fishes (Acanthuridae, Chaetodontidae, Kyphosidae, Labridae, Pomacanthidae, Siganidae), were used in combination with six morphological measurements, to examine the morphology of fishes in different social systems. A principal components analysis of morphological traits segregated species with high proportions of pairing individuals from non-pairing species along principal component 1, explaining 40.8 % of the variation. Pairing species were characterized by large eyes, concave foreheads, pointed snouts, deep bodies, and small maximum sizes. There was a significant positive relationship between these morphological traits (i.e., scores on PC1) and the prevalence of pairing within the Chaetodontidae (r 2 = 0.59; P = 0.026), Siganidae (r 2 = 0.72; P = 0.004), and Acanthuridae (r 2 = 0.82; P < 0.001). This was consistent when traits were corrected for phylogenetic effects. No pattern was evident in the scarine Labridae (r 2 = 0.15; P = 0.17). The morphological characteristics found among pairing species suggest that pairing species share common ecological traits, including foraging for small prey items in micro-topographically complex environments such as reef crevices. These ecological traits may have played a role in the evolution of pairing behavior and subsequently led to the development of reproductive patterns based on monogamy.
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Morphological structure in a reef fish assemblage
Coral Reefs, 2009Co-Authors: C. H. R. Goatley, David R. BellwoodAbstract:Two key morphological traits, horizontal gape and eye diameter, were measured in a large representative group of coral reef fishes. These morphological traits were used concurrently to assess their utility in exploring abilities of coral reef fishes at an assemblage level. A total of 1,218 specimens from 181 species found on the Great Barrier Reef were examined. Cryptobenthic fishes were included to provide a broader representation of reef fish groups. In the analyses, a clear morphological distinction was found between nocturnal and diurnal fishes. Nocturnal fishes had larger relative horizontal gapes and relative eye diameters by factors of 1.6 and 1.5, respectively. A bivariate plot separated into quadrants was used to assess the implications of morphological variation. The morphological measures reflected distinct ecological traits in each quadrant. Whilst nocturnal fishes had large relative gapes and eye diameters, diurnal predators and detritivores had the same wide gapes, but small relative eye diameters. Highly selective, visual feeders such as the Chaetodontidae and Pseudochromidae had large eyes and small gapes, whilst non-selective feeders with low visual dependence such as the grazing herbivores (Acanthuridae, Siganidae, etc.) had both small eye diameters and gape sizes. The analysis proved to be robust enough to apply to a wide assemblage, but with enough subtlety to distinguish morphological differences within individual families. The methods used in this study may have broad applications to other fish assemblages, both fossil and extant.
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a functional analysis of food procurement in two surgeonfish species acanthurus nigrofuscus and ctenochaetus striatus Acanthuridae
Environmental Biology of Fishes, 1993Co-Authors: Steven W Purcell, David R. BellwoodAbstract:The mechanisms of food procurement in the surgeonfishesCtenochaetus striatus andAcanthurus nigrofuscus from the Great Barrier Reef were determined by functional analyses of the jaws and associated structural elements (based on myological and osteological examinations and X-ray photographs) and by video analyses of actions of the mouth and body during feeding.Acanthurus nigrofuscus has relatively robust jaw bones. The movement of the elements during mouth opening is limited with a mean maximum gape angle of 112.8°. Each bite is relatively fast and is characterized by a quick nip at algal filaments, usually followed by a sidewads flick of the head. The jaws bear several broad multidenticulate teeth. It appears that these teeth engage turf algal strands which are either sheared during mouth closure or torn off as the head flicks sideways. InC. striatus, the jaw bones are considerably lighter than those ofA. nigrofuscus. There is much greater movement of the elements during mouth opening, resulting in a mean maximum gape angle of 177.6°. Each bite is slower than inA. nigrofuscus and is characterized by a wide gape as the mouth is applied to the substratum followed by a quick, upward flick of the lower jaw, with no sideways flick of the head. The jaws bear numerous elongate flexible teeth, with expanded incurved denticulate tips; those on the dentary often possessing a pointed blade-like process. It appears that these teeth brush particulate and epiphytic material from the surface of the turf algal strands and other substrata. These observations demonstrate howA. nigrofuscus andC. striatus are able to remove microalgae and detritus, respectively, from the same substratum. The results also demonstrate how relatively small differences in morphology can have a profound influence on the feeding abilities and trophic ecology of fishes.
Fabio Cortesi - One of the best experts on this subject based on the ideXlab platform.
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visual system development of the spotted unicornfish naso brevirostris Acanthuridae
The Journal of Experimental Biology, 2019Co-Authors: Valerio Tettamanti, Fanny De Busserolles, David Lecchini, Justin Marshall, Fabio CortesiAbstract:Ontogenetic changes of the visual system are often correlated with shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This habitat transition frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to mainly zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris changes primarily during the transition from the larval to the juvenile stage, with only minor modifications thereafter. Similarly, visual gene (opsin) expression based on RNA sequencing, although qualitatively similar between stages (all fish mainly expressed the same three cone opsins; SWS2B, RH2B, RH2A), also showed the biggest quantitative difference when transitioning from larvae to juveniles. The juvenile stage in particular seems mismatched with its reef-associated ecology, which may be due to this stage only lasting a fraction of the lifespan of these fish. Hence, the visual ontogeny found in N. brevirostris is very different from the progressive changes found in other reef fishes, calling for a thorough analysis of visual system development of the reef fish community.
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neoteny in visual system development of the spotted unicornfish naso brevirostris Acanthuridae
bioRxiv, 2019Co-Authors: Valerio Tettamanti, Fanny De Busserolles, David Lecchini, Justin Marshall, Fabio CortesiAbstract:Abstract Ontogenetic changes of the visual system are often correlated to shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This transition of habitat frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris do not change with the habitat or the feeding habits of each developmental stage. Instead, fishes showed a neotenic development with a slight change from larval to juvenile stages and not many modifications thereafter. Visual gene expression based on RNA sequencing mirrored this pattern; independent of stage, fishes mainly expressed three cone opsin genes (SWS2B, RH2B, RH2A), with a quantitative difference in the expression of the green opsin genes (RH2A and RH2B) when transitioning from larvae to juveniles. Hence, contrary to the ontogenetic changes found in many animals, the visual system is fixed early on in N. brevirostris development calling for a thorough analysis of visual system development of the reef fish community.
Justine Jean-lou - One of the best experts on this subject based on the ideXlab platform.
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Nouvelles mentions de nématodes spirurides (Nematoda, Spirurida, Guyanemidae, Philometridae & Cystidicolidae) de poissons marins de la Nouvelle-Calédonie, avec redescriptions de deux espèces et érection d’Ichthyofilaroides n. gen.
'EDP Sciences', 2020Co-Authors: Moravec František, Justine Jean-louAbstract:International audienceRecent examinations of spirurid nematodes (Spirurida) from deep-sea or coral reef marine fishes off New Caledonia, collected in the years 2006-2009, revealed the presence of the following five species: Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transferred from Ichthyofilaria Yamaguti, 1935) (females) (Guyanemidae) from the deep-sea fish Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (male fourth-stage larva and mature female) (Philometridae) from Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (female) (Cystidicolidae) from Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (males and females) from Naso lituratus and N. unicornis (Acanthuridae, Perciformes), and Ascarophisnema tridentatum Moravec et Justine, 2010 (female) from Gymnocranius grandoculis (Lethrinidae, Perciformes). Two species, I. novaecaledoniensis and A. nasonis, are redescribed based on light microscopical (LM) and scanning electron microscopical (SEM) examinations , the latter used in these species for the first time. Morphological data on the specimen of A. tridentatum from the new host species are provided. Philometra sp. (from E. maculatus) most probably represents a new gonad-infecting species of this genus. The newly established genus Ichthyofilaroides n. gen. is characterized mainly by the presence of a small buccal capsule and by the number and distribution of cephalic papillae in the female; it is the sixth genus in the Guyanemidae.L’étude récente de nématodes Spirurida de poissons marins de mer profonde ou des récifs coralliens au large de la Nouvelle-Calédonie, collectés dans les années 2006-2009, a révélé la présence des cinq espèces suivantes : Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transféré depuis Ichthyofilaria Yamaguti, 1935) (femelles) (Guyanemidae) du poisson de profondeur Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (larve mâle de quatrième stade et femelle mûre) (Philometridae) d’Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (femelle) (Cystidicolidae) de Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (mâles et femelles) de Naso lituratus et N. unicornis (Acanthuridae, Perciformes), et Ascarophisnema tridentatum Moravec et Justine, 2010 (femelle) de Gymnocranius grandoculis (Lethrinidae, Perciformes). Deux espèces, I. novaecaledoniensis et A. nasonis, sont redécrites sur la base de la microscopie optique et de la microscopie électronique à balayage, cette dernière étant utilisée pour la première fois chez ces espèces. Des données morphologiques sur le spécimen d’A. tridentatum de la nouvelle espèce hôte sont fournies. Philometra sp. (d’E. maculatus) représente très probablement une nouvelle espèce infectant les gonades de ce genre. Le genre nouvellement établi Ichthyofilaroides n. gen. se caractérise principalement par la présence d’une petite capsule buccale et par le nombre et la répartition des papilles céphaliques chez la femelle. C’est le sixième genre des Guyanemidae
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New records of spirurid nematodes (Nematoda, Spirurida, Guyanemidae, Philometridae & Cystidicolidae) from marine fishes off New Caledonia, with redescriptions of two species and erection of Ichthyofilaroides n. gen.
'EDP Sciences', 2020Co-Authors: Moravec František, Justine Jean-louAbstract:Recent examinations of spirurid nematodes (Spirurida) from deep-sea or coral reef marine fishes off New Caledonia, collected in the years 2006–2009, revealed the presence of the following five species: Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transferred from Ichthyofilaria Yamaguti, 1935) (females) (Guyanemidae) from the deep-sea fish Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (male fourth-stage larva and mature female) (Philometridae) from Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (female) (Cystidicolidae) from Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (males and females) from Naso lituratus and N. unicornis (Acanthuridae, Perciformes), and Ascarophisnema tridentatum Moravec et Justine, 2010 (female) from Gymnocranius grandoculis (Lethrinidae, Perciformes). Two species, I. novaecaledoniensis and A. nasonis, are redescribed based on light microscopical (LM) and scanning electron microscopical (SEM) examinations, the latter used in these species for the first time. Morphological data on the specimen of A. tridentatum from the new host species are provided. Philometra sp. (from E. maculatus) most probably represents a new gonad-infecting species of this genus. The newly established genus Ichthyofilaroides n. gen. is characterized mainly by the presence of a small buccal capsule and by the number and distribution of cephalic papillae in the female; it is the sixth genus in the Guyanemidae.L’étude récente de nématodes Spirurida de poissons marins de mer profonde ou des récifs coralliens au large de la Nouvelle-Calédonie, collectés dans les années 2006-2009, a révélé la présence des cinq espèces suivantes : Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transféré depuis Ichthyofilaria Yamaguti, 1935) (femelles) (Guyanemidae) du poisson de profondeur Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (larve mâle de quatrième stade et femelle mûre) (Philometridae) d’Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (femelle) (Cystidicolidae) de Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (mâles et femelles) de Naso lituratus et N. unicornis (Acanthuridae, Perciformes), et Ascarophisnema tridentatum Moravec et Justine, 2010 (femelle) de Gymnocranius grandoculis (Lethrinidae, Perciformes). Deux espèces, I. novaecaledoniensis et A. nasonis, sont redécrites sur la base de la microscopie optique et de la microscopie électronique à balayage, cette dernière étant utilisée pour la première fois chez ces espèces. Des données morphologiques sur le spécimen d’A. tridentatum de la nouvelle espèce hôte sont fournies. Philometra sp. (d’E. maculatus) représente très probablement une nouvelle espèce infectant les gonades de ce genre. Le genre nouvellement établi Ichthyofilaroides n. gen. se caractérise principalement par la présence d’une petite capsule buccale et par le nombre et la répartition des papilles céphaliques chez la femelle. C’est le sixième genre des Guyanemidae
Michel Kulbicki - One of the best experts on this subject based on the ideXlab platform.
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assembly rules of fish communities in tuamotu archipelago atoll lagoons the case of fangatau a lagoon dominated by giant clam habitats
Marine Biodiversity, 2018Co-Authors: Gerard Moutham, Michel Kulbicki, Antoine Gilbert, Jonas Tuahine, Serge AndrefouetAbstract:Assembly rules of fish communities in Tuamotu Archipelago lagoons have been previously investigated but without considering lagoons where shallow habitats are dominated by giant clam populations. We tested if assembly rules for 14 atolls were challenged by such an atoll (Fangatau), and in doing so investigated the robustness of inter-island population patterns to specialized habitats. Fangatau had significantly higher proportions of Pomacentridae and Scaridae, but lower proportions of Labridae, Acanthuridae, Balistidae and Serranidae. Functionally, herbivores, omnivores, species <7 cm or between 50 and 80 cm, and species forming schools were found in higher proportions, while sessile invertebrate feeders, medium-size species (30–50 cm) and solitary species were lower. These differences were rather related to Fangatau isolation, as no other physical or ecological feature could explain them. Total richness, functional richness, and functional redundancy remained correlated mainly to atoll size, without outliers related to high clam abundance and presence of peculiar habitats.
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effects of marine reserves on coral reef fish communities from five islands in new caledonia
Coral Reefs, 1997Co-Authors: Laurent Wantiez, Pierre Thollot, Michel KulbickiAbstract:The effect of marine reserve protection on coral reef fish communities was studied on five islands located in the southwest lagoon of New Caledonia. Commercial fish communities and Chaetodontidae, sampled before fishing prohibition and after five years of protection, were compared. Reference stations were also sampled to assess variability in unprotected communities on the same time scale. The hypothesis that marine reserves protect and develop fish stocks was confirmed. Species richness, density and biomass of fish on the protected reefs increased respectively by 67%, 160% and 246%. This increase was statistically significant, whereas the reference stations showed only a small increase in density. There were significant increases in the species richness, density and biomass of the major exploited fish families (Serranidae, Lutjanidae, Lethrinidae, Mullidae, Labridae, Scaridae, Siganidae and Acanthuridae) and also of the Chaetodontidae. No significant increase in the mean lengths of fishes was noted among the main species, with the exception of one species of Siganid. Size structure changed for most of the main species, as the proportion of small individuals increased after five years of protection. Detrended correspondance analysis indicated that marine reserve protection was the most important determinant of the fish community structure. The second determinant was the position along an inshore-offshore gradient. Marine reserve protection resulted in an increase in the relative abundance and species richness of large edible species within the assemblages.
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effects on coral reef fish communities from five islands of new caledonia s southern lagoon marine reserve
1995Co-Authors: Laurent Wantiez, Pierre Thollot, Michel KulbickiAbstract:The effect of the marine reserve on coral reef fish communities was studied on five islands located ia New Caledonia's Southern Lagoon. Fish communities were sampled by line transect (50 m long, variable width). Sampling was undertaken before the fishing closure and after five years of protection. Reference stations located in unprotected sites were also sampled to assess natural variability on the same time scale. Species richness and density and fish biomass on the protected reefs increased respectively by 67 %, 160 % and 246 % . This increase was far more substantial than the variations observed at the reference stations. An enhancement of the species richness and density and the biomass of the major commercial fish families was ob served: Serranidae (groupers), Lutjanidae (snappers), Lethrinidae (emperors), Mullidae (goatfishes), Labridae (wrasses), Scaridae (parrotfishes), Siganidae (rabbitfishes) and Acanthuridae (surgeonfishes). Chaetodontidae (butterflyfishes), which are thought to be indicators of reef heaith, had also developed. No significant increase in the mean size of fish was noted among the main species with the exception of the rabbitfish, Siganus doliarus. Size structure had, however, generally changed because of the presence of more small specimens after five years of protection. This change to fish community structure can first attributed to the effects of the marine reserve, leading to an increase in the relative abundance of large edible species within the aggregations. Fish populations are also distributed according to an inshore-offshore gradient.This before-and-after study validates several marine reserve benefits: protection of spawning stock biomass, development of fish populations, sustaining of population age structure. Marine reserves also indirectly protect fish populations by improving the habitat.
