Distribution of Acantharia in the Western Sargasso Sea in Correspondence with “Thermal Fronts”1

A study of plankton samples collected in the Western Sargasso Sea during nine cruises has shown discontinuity between samples from different latitudes as regards their percentage, abundance, and number of species of Acantharia. Limits separating zones rich in Acantharia from those poor in Acantharia were singled out. The latitude at which the difference in abundance occurs can vary. This is in accord with differences in primary production, phytoplankton, and mesopelagic fishes noted by other workers who believe that the points of these faunal changes correspond to a temperature change indicated as “thermal fronts.”     

Diversity,Ecology and Biogeochemistry of Cyst-Forming Acantharia (Radiolaria) in the Oceans

Marine planktonic organisms that undertake active vertical migrations over their life cycle are important contributors to downward particle flux in the oceans. Acantharia, globally distributed heterotrophic protists that are unique in building skeletons of celestite (strontium sulfate), can produce reproductive cysts covered by a heavy mineral shell that sink rapidly from surface to deep waters. We combined phylogenetic and biogeochemical analyses to explore the ecological and biogeochemical significance of this reproductive strategy. Phylogenetic analysis of the 18S and 28S rRNA genes of different cyst morphotypes collected in different oceans indicated that cyst-forming Acantharia belong to three early diverging and essentially non symbiotic clades from the orders Chaunacanthida and Holacanthida. Environmental high-throughput V9 tag sequences and clone libraries of the 18S rRNA showed that the three clades are widely distributed in the Indian, Atlantic and Pacific Oceans at different latitudes, but appear prominent in regions of higher primary productivity. Moreover, sequences of cyst-forming Acantharia were distributed evenly in both the photic and mesopelagic zone, a vertical distribution that we attribute to their life cycle where flagellated swarmers are released in deep waters from sinking cysts. Bathypelagic sediment traps in the subantarctic and oligotrophic subtropical Atlantic Ocean showed that downward flux of Acantharia was only large at high-latitudes and during a phytoplankton bloom. Their contribution to the total monthly particulate organic matter flux can represent up to 3%. High organic carbon export in cold waters would be a putative nutritional source for juveniles ascending in the water column. This study improves our understanding of the life cycle and biogeochemical contribution of Acantharia, and brings new insights into a remarkable reproductive strategy in marine protists.     

Distribution patterns and sexual segregations of Scyliorhinus canicula (L.) in the Cantabrian Sea

The influence of factors such as depth, near bottom temperature, near bottom salinity, fish length and diet composition on the aggregation of Scyliorhinus canicula in the Cantabrian Sea was examined. The correlation between these variables and the aggregations of each sex was low. A priori juvenile males and females were not highly discriminated by any of these environmental variables (depth, temperature and salinity) based on a multivariate analysis. The best discriminated groups were the new recruits, and depth and longitude were the variables that contributed most to their segregation, while adult males had some preference for shallower and warm waters. Diet composition varied with body size but it was quite similar in both sexes among which no significant differences were observed. An increase in feeding intensity and abundance of Euphasiacea prey taxa was found in adult females compared to males.     

Spatial distribution and abundance of nonindigenous coral genus Tubastraea (Cnidaria, Scleractinia) around Ilha Grande, Brazil.

The distribution and abundance of azooxanthellate coral Tubastraea Lesson, 1829 were examined at different depths and their slope preference was measured on rocky shores on Ilha Grande, Brazil. Tubastraea is an ahermatypic scleractinian nonindigenous to Brazil, which probably arrived on a ship's hull or oil platform in the late 1980's. The exotic coral was found along a great geographic range of the Canal Central of Ilha Grande, extending over a distance of 25 km. The abundance of Tubastraea was quantified by depth, using three different sampling methods: colony density, visual estimation and intercept points (100) for percentage of cover. Tubastraea showed ample tolerance to temperature and desiccation since it was found more abundantly in very shallow waters (0.1-0.5 m), despite the fact that hard substratum is available at greater depths at all the stations sampled. At most sites, 1 to 5 colonies per 0.25 m2 were found most frequently, but occasionally more than 50 colonies were found per 0.25 m2, indicating a somewhat gregarious spatial distribution for this coral. The coral Tubastraea was found to occupy slopes of every possible angle in the Canal Central of Ilha Grande, but more colonies were found occupying slopes of 80 to 100 degrees. Therefore, its insensitivity to angles of recruitment and its tolerance for different depths makes it an organism with great ecological tolerance, with a potential to colonize new areas and increase its current range in Brazil's coastal waters.     

A deep nursery for juveniles of the zebra angelfish <Emphasis Type="Italic">Genicanthus caudovittatus</Emphasis>

Juveniles of many coral reef fish species are thought to either follow the same bathymetric distribution patterns as the adults, or to occupy shallower waters. However, our knowledge base suffers a dearth of data from the deep reefs (>40 m). In a recent survey of the deep reefs of the northern Gulf of Aqaba (<65 m), we examined the bathymetric distribution of 26 diurnal zooplanktivorous species. In sharp contrast to the general trend known from the literature and from this research, the abundance of juvenile zebra angelfish, Genicanthus caudovittatus, peaked at deeper waters (60–65 m) compared with the adults (30 m). This suggests that the deeper reefs may serve as nursery grounds for the zebra angelfish. Peak juvenile abundance coincided with relatively low predator abundances. This raises the question, which factors constrain the bathymetric distribution of the remaining species. Our findings stress the potential importance of deep coral reef research for understanding the ecological patterns and processes that govern reef community structure.     

Distribution of perch (Perca fluviatilis L.) during their first year of life in Lake Constance

The distribution and behaviour of larval and juvenile perch (Perca fluviatilis L.) were studied for two years in large, deep Lake Constance. After hatching larvae were transported by water currents to the open water. The majority of larvae remained in the pelagic zone for about one month. In both years, their return to the littoral zone coincided with the decline of pelagic zooplankton abundance. After returning to the littoral zone, juveniles stayed among submerged macrophytes within 5 m depth and lived apart from larger perch which lived at depths of 6–20 m. By late summer, juveniles changed their distribution pattern: during the day they stayed intensively close to piers and ports, but increased their swimming activity at dusk, cruising among shallow and deep waters and feeding on zooplankton, and rested on the bottom at night. This behaviour appears to be related to the decrease of inshore food resources and to the presence of predators in deeper water. 0⁺ perch left the littoral zone and moved into deep waters when autumnal mixing began in late October. They overwintered near the bottom at depths of more than 30 m. During most of the year, juvenile and adult perch were separated from each other. But as soon as they occupied the same habitat, the occurrence of cannibalism increased.     

Composition, spatial and temporal variations of Chaetognatha in Guanabara Bay, Brazil

This paper presents the specific composition and distributionof adult chaetognaths in Guanabara Bay, Brazil. A comparisonhas been made between chaetognath and copepod distribution patterns.Three areas were distinguished within Guanabara Bay: an externalarea, influenced by oceanic waters; an internal area, influencedby fluvial waters; and a transitional area between the two.Monthly samples were collected by horizontal surface hauls usinga conical net with 200µm mesh. Three species were identified:Sagitta friderici, S.enflata and S.hispida. Sagitta fridericiwas the dominant species and occurred throughout the year atthe three areas. Sagitta enflata and S.hispida were limitedto the more saline waters. Generally, greater densities of chaetognathswere observed following copepod peakden sities. Temperatureand salinity associated with copepod abundance were the mostimportant factors affecting the distribution pattern and theabundance of chaetognath species in Guanabara Bay.     

The influence of spawning and nursery grounds on the distribution of sole Solea solea (L.) in the Irish Sea, Bristol Channel and adjacent areas

In the coastal waters of west England and Wales, sole, Solea solea (L.), are found in greatest abundance in the north-east Irish Sea and the Bristol Channel. Data from research and charter vessel surveys in these areas showed differences in the spatial distribution of age-groups between the two regions. Juvenile sole (0-group, 1-group and 2-group) were found almost exclusively in the shallow (<20 m deep) parts of the north-east Irish Sea and adults (3-group and older) were also found in the same area and in deeper water. In contrast, while juvenile sole in the Bristol Channel were abundant in and around Carmarthen Bay, Swansea Bay and the Severn estuary, they also occurred frequently in deeper areas of the Bristol Channel down to depths of 40 m. Adult sole in the Bristol Channel were also relatively more abundant at depths >40 m than adults in the Irish Sea. The movements of sole which produce these patterns of distribution in the two areas are also shown by the recaptures of sole tagged in the respective nursery areas. The differences in the distribution of sole in the two areas may be related to the depths of their spawning grounds and the distances that maturing fish must travel to reach them.

In the north-east Irish Sea, sole spawning grounds are generally in waters of <40 m depth and within an extensive area of relatively shallow and gently shelving sediments close to the coastal nursery grounds. The bottom topography of the Bristol Channel is more steeply shelving and the spawning grounds of sole are at a depth of 40–75 m off Trevose Head, ≈100 km from the main nursery areas. The hydrographic conditions in the two areas are described, and it is concluded that one of the more important requirements of a successful spawning ground is the presence of suitable hydrographic conditions to transport eggs and larvae to nursery areas.     

Distribution of phytoplankton and nutrients in relation to different water masses in the area around Elephant Island, Antarctica

During January March 1996 the U.S. Antarctic Marine Living Resources program carried out an extensive multidisciplinary study in a 40,000 km² sampling grid around Elephant Island, Antarctica. The physical, chemical, optical, and biological characteristics of the upper water column (0–750 m) were determined at 91 hydrographic stations. Analysis of the temperature and salinity data showed that six different hydrographic zones could be differentiated. The biological (phytoplankton distribution and abundance) and chemical (inorganic nutrient concentrations) data also showed characteristic differences within each of these six zones. In spite of high concentrations of inorganic N, P, and Si in all six zones, all stations in the northwest portion of the sampling grid (Drake Passage waters) showed very low chlorophyll-a concentrations in surface waters and a sub-surface maximum at increased depth. As stations in this zone have a relatively stable upper mixed layer of 40 m, excess macro-nutrients, and adequate solar radiation for maximal photosynthetic rates, this suggests that rates of primary production in this zone are limited by a micro-nutrient such as Fe. Phytoplankton abundance was much greater in the Bransfield Strait, in waters influenced by Bellingshausen Sea Water, and in the frontal zones where these water masses mix with Drake Passage waters. Relatively low and deeply distributed phytoplankton abundance was found at all stations in the southeastern portion of our sampling grid, where the upper water column was very weakly stratified and showed the characteristics of Weddell Sea water. The areas of enhanced phytoplankton biomass in the AMLR sampling grid roughly correspond to the areas where krill are generally also found in greater abundance. The overall biological productivity of the Elephant Island region would thus appear to be dependent upon the circulation patterns of the major water masses that intrude into this area. Received: 28 October 1996 / Accepted: 20 January 1997     

Distribution and reproduction of the Patagonian toothfish Dissostichus eleginoides Smitt around the Falkland Islands

Population characteristics of the Patagonian toothfish Dissostichus eleginoides were investigated based on material collected from both trawl and longline fisheries in Falkland Islands' waters. The fish occurred between 56 and 2122 m and attained 225 cm total length ( L _T). Males matured earlier, L _T at 50% maturity was 86 cm for males v . 90 cm for females. Subadult fish foraged at depths of <600 m, whereas adult Patagonian toothfish lived at >600 m. Spawning occurred on slopes of the Burdwood Bank at c . 1000 m depth with a minor peak in May, and a major peak in July to August. Males arrived at the spawning grounds first. Between spawning peaks both sexes remained around the Burdwood Bank with males occurring at greater depths than females. The Patagonian toothfish in south‐east Patagonia and the Falkland Islands had a long juvenile and sub‐adult period in the relatively shallow and warm waters of the outer shelf and upper slope unlike that of juveniles in other Patagonian toothfish populations. The migratory life style of the south‐west Atlantic population is probably very different from that of other populations, which tend to be resident as they are inclined to inhabit the waters around oceanic islands and sea mounts with narrow shelf areas.     

Dynamics of aerobic anoxygenic phototrophic bacteria in the East China Sea

Aerobic anoxygenic phototrophic bacteria (AAPB) are a group of heterotrophic bacteria capable of photosynthesis. The dynamics of AAPB in the East China Sea, a typical marginal sea characterized by diverse physical-chemical and ecological conditions, were investigated from April 2002 to September 2003. The results showed that the abundance of AAPB varied from 0.16 to 7.9 x 10(4) cells mL(-1) and the percentage of AAPB (AAPB%) in the total heterotrophic bacterial abundance varied from 0.5% to 11.6% over a gradient of environmental conditions. The abundance of AAPB and AAPB% was higher in coastal and continental shelf waters than in oceanic waters. An interesting seasonal pattern was observed in the Yangtze River estuary: the abundance of AAPB was highest in summer and lowest in winter; however, AAPB% was higher in winter than in the other seasons. Throughout the investigation period, variation of AAPB abundance with temperature was much less than that of nonAAPB abundance, suggesting that low temperature was not a limiting factor for AAPB in this case. Close correlation between AAPB and chlorophyll a was observed in each season, suggesting that dependence of AAPB on dissolved organic carbon produced by phytoplankton (PDOC) may be one key factor controlling AAPB distribution.     

Recent trends in the abundance of plaice Pleuronectes platessa and cod Gadus morhua in shallow coastal waters of the Northeastern Atlantic continental shelf – a review

Shallow, near-shore water habitats on the continental shelf of the Northeast Atlantic have been productive fishing areas in the past. Here, we review the present knowledge about (i) recent trends in the abundance of plaice and cod in these habitats and (ii) hypotheses regarding the factors responsible for any trends. At present, only a few studies exist on the trends of abundance of plaice or cod, namely from the Bay of Biscay, the North Sea and the Skagerrak/Kattegat. They suggest a declining abundance in coastal, shallow areas and – at least for plaice – a latitudinal gradient with an erosion of the southern distribution boundary in the Bay of Biscay and deepening of stocks in the North Sea. In contrast, no trend in shallow water abundance of plaice similar to a decline in deep-water stocks during the 1970s and their slow recovery during the 2000s is apparent in the Skagerrak/Kattegat. Although shallow habitats fundamentally differ from deeper areas by the prevalence of juvenile stages, the declining trends coincide with decreasing abundance/landings and spatial stock relocations in the deeper areas. Whether this indicates a common trend pointing at connectivity between shallow and deep water remains open. Fundamental differences exist in the suggested causes of the trends in different geographical areas. High fishing pressure together with low local recruitment apparently prevents the recovery of overexploited plaice and cod stocks in the Skagerrak/Kattegat. In contrast, the responses of juveniles and adult fish to increasing seawater temperature are the main hypotheses for changes in distribution and abundance of both fish species in the North Sea/Bay of Biscay. However, temperature alone cannot explain the observed decline of fish in coastal areas, and the causes may be more complex, involving nutrient loading, primary productivity or food availability, although at present, knowledge of these factors is insufficient.     

Influence of Habitat Structure on Pomacentrus sulfureus, A Western Indian Ocean Reef Fish

The influence of habitat on the distribution and abundance of Pomacentrus sulfureus was investigated on coral reefs in Zanzibar. Fish censuses were conducted using the simultaneous belt-transect method and substrate data were gathered using a point-base method. Densities of juvenile and adult P. sulfureus were examined in relation to habitat composition and structure. The influence of habitat structure on coral reef fishes remains debated and has been obscured by the various methods, scales and levels of detail that have been used. In this study, we compared two measures of structural complexity. One was a contour measure (rugosity) and the other was the percent cover of branching structures. Both were applied on the same scale but differed in the level of detail. P. sulfureus was distributed in an uneven pattern around Zanzibar Island and the distribution appeared to reflect local and regional differences in habitat structure. Multiple regression models identified relations between juvenile and adult P. sulfureus abundance and specific habitat features. The majority of the variation in juvenile numbers was attributed to percent cover of branching structures, the high-resolution measure. However, adult abundance was unrelated to this measure. Rugosity, the low-resolution measure of structural complexity, appeared to influence neither adult nor juvenile P. sulfureus. The best predictor of adult abundance was substrate diversity (inverse relationship), which, however, did not contribute to the proportion of explained variation in juvenile abundance. In addition, there was a weak positive relationship between adult abundance and the number of hard coral growth forms present. The results indicate that P. sulfureus exhibit an ontogenetic shift in habitat use. However, the regression models also revealed that adults per se have a positive effect on juvenile numbers. We suggest that the limited habitat use of juvenile P. sulfureus is contained within that of conspecific adults, and that juveniles are likely to adopt more general habitat associations as they grow.     

Interannual fluctuations in copepod abundance and contribution of small forms in the Drake Passage during austral summer

The relative importance of small forms of copepods has been historically underestimated by the traditional use of 200?C300-??m mesh nets. This work quantified the distribution and abundance of copepods, considering two size fractions (<300???m and >300???m), in superficial waters (9?m deep) of the Drake Passage and contributed to the knowledge of their interannual fluctuations among three summers. Four types of nauplii and eleven species of copepods at copepodite and adult stages were identified, with abundance values of up to 13 ind L^?1 and 28,300???g C m^?3. The <300-??m fraction, composed of Oithona similis, small cyclopoids and nauplii, dominated the copepod communities in the 3?years; it accounted for more than 77% of the total number and for between 40 and 63% of the total biomass. Changes in density and biomass values among the three cruises differed according to copepod size fraction and water mass; the >300-??m fraction showed no changes among the 3?years, both in Antarctic (density and biomass) and in Subantarctic waters (density), whereas the <300-??m fraction showed higher (density and biomass) values in 2001 both in Subantarctic and in Antarctic waters. Sea surface temperature and its anomaly accounted for the largest proportion of variability in copepod density and biomass, particularly for the <300-??m fraction.     

Agonistic Behaviour and Development of Territoriality During Ontogeny of the Sea Anemone Dwelling Crab Allopetrolisthes Spinifrons (H. Milne Edwards, 1837) (Decapoda: Anomura: Porcellanidae)

Allopetrolisthes spinifrons is an ectosymbiotic crab of the sea anemone Phymactis clematis. As a consequence of low host abundance, these represent a scarce and limited resource for the crab. Additionally, the relatively small size of the sea anemone host suggests that few symbiotic crabs can cohabit on one host individual, forcing crabs to adopt a territorial behaviour. In order to examine the potential presence and ontogenetic development of territoriality, the agonistic behaviour between crabs of various ontogenetic stages (adults, juveniles, and recruits) was studied in the laboratory. Laboratory experiments demonstrated that adult or juvenile crabs aggressively defended their sea anemone hosts against adult or juvenile intruders, respectively, but both adult and juvenile crabs tolerated recruits. Adult crabs behaved indifferently towards juvenile crabs, sometimes tolerating them, sometimes expelling them. Recruits never showed agonistic behaviour among themselves. The agonistic interactions observed in the laboratory and the uniform population distribution pattern on sea anemones recently described for A. spinifrons indicate that this species exhibits territorial behaviour, which develops during ontogeny. Territoriality in this species and other symbiotic decapods may function as a density-dependent mechanism of population regulation, being mediated by the availability of hosts. Resource monopolisation behaviours may be common among other symbiotic and free-living marine invertebrates inhabiting discrete habitats that represent a limiting resource.     

Agonistic Behaviour and Development of Territoriality During Ontogeny of the Sea Anemone Dwelling Crab Allopetrolisthes Spinifrons (H. Milne Edwards, 1837) (Decapoda: Anomura: Porcellanidae)

Allopetrolisthes spinifrons is an ectosymbiotic crab of the sea anemone Phymactis clematis . As a consequence of low host abundance, these represent a scarce and limited resource for the crab. Additionally, the relatively small size of the sea anemone host suggests that few symbiotic crabs can cohabit on one host individual, forcing crabs to adopt a territorial behaviour. In order to examine the potential presence and ontogenetic development of territoriality, the agonistic behaviour between crabs of various ontogenetic stages (adults, juveniles, and recruits) was studied in the laboratory. Laboratory experiments demonstrated that adult or juvenile crabs aggressively defended their sea anemone hosts against adult or juvenile intruders, respectively, but both adult and juvenile crabs tolerated recruits. Adult crabs behaved indifferently towards juvenile crabs, sometimes tolerating them, sometimes expelling them. Recruits never showed agonistic behaviour among themselves. The agonistic interactions observed in the laboratory and the uniform population distribution pattern on sea anemones recently described for A . spinifrons indicate that this species exhibits territorial behaviour, which develops during ontogeny. Territoriality in this species and other symbiotic decapods may function as a density-dependent mechanism of population regulation, being mediated by the availability of hosts. Resource monopolisation behaviours may be common among other symbiotic and free-living marine invertebrates inhabiting discrete habitats that represent a limiting resource.     

On the celestite-secreting Acantharia and their effect on seawater strontium to calcium ratios

Significant variations in the Sr/Ca in waters from the eastern Indian Ocean in the vicinity of Australia, both from the surface and from shallow depth profiles, are documented. The strontium sulfate-secreting protozoans Acantharia, which are common in the upper 400 m of the oceans, especially at low latitudes, contribute substantially to changes in the Sr/Ca of oceanic waters by extracting Sr for the formation of their skeletons. Below such depths, these organisms dissolve and the Sr/Ca of seawater regains its ‘conservative’ nature. This mechanism accounts for some of the variability of the Sr/Ca near the surface of the ocean, but this may still be found at depth as surface waters become entrained at greater depths. It is argued here that the noted Sr/Ca variations may explain discrepancies between coral data sets from different parts of the oceans, and calls for caution when reconstructing sea-surface temperatures from the Sr/Ca of corals.     

Spatial and depth-associated distribution patterns of shallow gorgonians in the Algarve coast (Portugal, NE Atlantic)

The ecological role of gorgonians for marine rocky bottoms is worldwide recognized, but the information on the distribution patterns of NE Atlantic temperate species is insufficient, considering current global, regional and local threats. To overcome the lack of information on the spatial distribution patterns of gorgonians in south Portugal, in 2009/2010, the occurrence and abundance of gorgonian species in rocky bottoms were quantified over more than 25 km of coast (37.1°N/8.6°W) down to 30 m depth. Eunicella labiata, Eunicella gazella, Eunicella verrucosa and Leptogorgia sarmentosa were abundant and frequent in the studied area, while Leptogorgia lusitanica was less abundant. All species evidenced a similar depth pattern, that is abundance significantly increased with depth below 15 m. At shallower waters (up to 15 m), the distribution of gorgonians may be constrained by abiotic factors and competition with algae. Indeed, the abundance of gorgonians was negatively correlated with the percentage cover of algae along the depth gradient, but gorgonians and sponges coexist. Competition among gorgonian species also seems to be low in this area because of the similarity in the abundance pattern observed for the most abundant species and also their high association. In NE Atlantic shallow temperate rocky bottoms, the distribution of gorgonians seems to be influenced by environmental factors and biological interactions, namely competition (algae) and coexistence (sponges and other gorgonians).     

Distribution of marine viruses and their potential hosts in Prydz Bay and adjacent Southern Ocean,Antarctic

Viruses play a key role in all marine ecosystems, and yet little is known of their distribution in Antarctic waters, especially in bathypelagic waters (>1000 m). In this study, the abundance and distribution of viruses and their potential hosts from the surface to the bottom of Prydz Bay, Antarctic, was investigated using flow cytometry. Viruses and autotrophs were abundant in nearshore and continental shelf waters, while heterotrophic bacteria and picoeukaryotes were abundant in offshore waters. Virus and bacteria abundances generally decreased with increasing depth but increased slightly just above the seafloor. Within the water column, maximum virus numbers coincided with the maximum values of chlorophyll a (when greater than 0.1 μg l^?1), in the surface and subsurface (25 m). In the open ocean, however, virus abundance usually correlated with bacterial abundance at greater depths (50, 300 and 500 m) where the surface chlorophyll a concentration was lower than 0.1 μg l^?1. Viral abundance was correlated with the host cell abundance, and this was different in different pelagic zones (bacteria and autotrophs (i.e., chlorophyll a concentration) in the epipelagic waters, picoeukaryotes and bacteria in mesopelagic waters and bacteria in bathypelagic waters). Principle component analysis and Pearson correlation analysis indicated that there was a close relationship between virus abundance and chlorophyll a, bacteria and nutrients (NO₂ + NO₃, phosphate and silicate), and picoeukaryote abundance was mainly correlated with water depth and salinity.     

Microhabitat use of juvenile coral reef fish in Palau

While relationships between adult fish density and structural habitat features are well established, relatively little is known about the habitat associations of juvenile reef fish. In a reserve system in Palau, we quantified microhabitat association with juvenile reef fish community structure, and determined the influence of foraging space, predator size and confamilial attraction on juvenile and adult pomacentrid abundance. Habitat structure and juvenile reef fish communities differed significantly among microhabitats with one exception: no difference was found between foliose and consolidated rubble microhabitats. Overall, pomacentrids characterised the juvenile community structure of each microhabitat. The abundance of early juvenile pomacentrids is simultaneously determined by microhabitat structure and predator size, with little evidence for settlement selection near adults. The results also suggest that the influence of habitat structure become weaker with ontogeny which in part, drives large predators to negatively influence the abundance of adult pomacentrids. The results have important implications on management, specifically in prioritizing areas for protection, and in modeling the impacts of habitat loss on reef fish communities.