Influence of hard bottom morphology on fish assemblages of the continental shelf off Georgia, southeastern USA

Various reef types worldwide have inconsistent relationships among fish assemblage parameters and benthic characteristics, thus there is a need to identify factors driving assemblage structure specific to each reef type and locale. Limestone ledges are known to be key habitats for bottom fish on the continental shelf of the southeastern USA, however, the specific factors that link them to fish assemblages have not been quantified. Bottom fishes and habitat characteristics on ledges were surveyed at a study site located centrally in the southeastern USA continental shelf. Species richness, diversity, abundance, and biomass of fish were higher at ledges than on flat bottom. Species richness, abundance, and biomass of fish were well explained by ledge variables including percent cover of sessile invertebrates, total height, and height of undercut recesses. Multivariate analyses based on biomass of individual species at ledges revealed two fish assemblages associated with four ledge types. One assemblage was associated with ledges that were tall, heavily colonized with sessile invertebrates, large in area, and did or did not have undercuts. The other assemblage was associated with ledges that were short, not undercut, smaller in area, and were or were not heavily colonized by invertebrates. Seafloor classification schemes presently used in the region do not adequately capture hard bottom diversity to identify the location and extent of essential fish habitats for ecological and fisheries purposes. Given that ledges cover only ∼1% to 5% of the southeastern USA continental shelf, they merit the highest levels of consideration in regional research, conservation, and management plans.

Biogeographic characterization of fish communities and associated benthic habitats within the Flower Garden Banks National Marine Sanctuary: sampling design and implementation of scuba surveys on the coral caps

The Flower Garden Banks National Marine Sanctuary (FGBNMS) is located in the northwestern Gulf of Mexico approximately 180 km south of Galveston, Texas. The sanctuary’s distance from shore combined with its depth (the coral caps reach to within approximately 17 m of the surface) result in limited exposure of this coral reef ecosystem to natural and human-induced impacts compared to other coral reefs of the western Atlantic. In spite of this, the sanctuary still confronts serious impacts including hurricanes events, recent outbreaks of coral disease, an increase in the frequency of coral bleaching and the massive Diadema antillarum die-off during the mid-1980s. Anthropogenic impacts include large vessel anchoring, commercial and recreational fishing, recreational scuba diving, and oil and gas related activities. The FGBNMS was designated in 1992 to help protect against some of these impacts. Basic monitoring and research efforts have been conducted on the banks since the 1970s. Early on, these efforts focused primarily on describing the benthic communities (corals, sponges) and providing qualitative characterizations of the fish community. Subsequently, more quantitative work has been conducted; however, it has been limited in spatial scope. To complement these efforts, the current study addresses the following two goals put forth by sanctuary management: 1) to develop a sampling design for monitoring benthic fish communities across the coral caps; and 2) to obtain a spatial and quantitative characterization of those communities and their associated habitats.

Status of coral reef ecosystems in a marine managed area in St. Croix, USVI [poster]

This poster presents information on the status and trends of coral reef ecosystems in St. Croix, US Virgin Islands (USVI). Data were collected by NOAA’s Center for Coastal Monitoring and Assessment Biogeography Branch (CCMA-BB) from 2001-2006 at 1,275 random locations in and around Buck Island Reef National Monument (BIRNM). The main objective was to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure; to provide spatially explicit information on the distribution of key species or groups of species; and to compare community structure inside versus outside of BIRNM.

Diet shifts of juvenile red snapper (Lutjanus campechanus) with changes in habitat and fish size

We examined the diets and habitat shift of juvenile red snapper (Lutjanus campechanus) in the northeast Gulf of Mexico. Fish were collected from open sand-mud habitat (little to no relief), and artificial reef habitat (1-m3 concrete or PVC blocks), from June 1993 through December 1994. In 1994, fish settled over open habitat from June to September, as shown by trawl collections, then began shifting to reef habitat — a shift that was almost completed by December as observed by SCUBA visual surveys. Stomachs were examined from 1639 red snapper that ranged in size from 18.0 to 280.0 mm SL. Of these, 850 fish had empty stomachs, and 346 fish from open habitat and 443 fish from reef habitat contained prey. Prey were identified to the lowest possible taxon and quantified by volumetric measurement. Specific volume of particular prey taxa were calculated by dividing prey volume by individual fish weight. Red snapper shifted diets with increasing size. Small red snapper (<60 mm SL) fed mostly on chaetognaths, copepods, shrimp, and squid. Large red snapper (60–280 mm SL) shifted feeding to fish prey, greater amounts of squid and crabs, and continued feeding on shrimp. We compared red snapper diets for overlapping size classes (70–160 mm SL) of fish that were collected from both habitats (Bray-Curtis dissimilarity index and multidimensional scaling analysis). Red snapper diets separated by habitat type rather than fish size for the size ranges that overlapped habitats. These diet shifts were attributed to feeding more on reef prey than on open-water prey. Thus, the shift in habitat shown by juvenile red snapper was reflected in their diet and suggested differential habitat values based not just on predation refuge but food resources as well.

A Review of the parasitic copepods of fish recorded from Ceylon with description of additional forms

The beginning of our knowledge of the copepods parasitic on fish from Ceylon is due to Bassett-Smith (1898 a) who, in a paper on "Further New Parasitic Copepods found on Fish in the Indo-Tropical Region", included seven species collected at Trincomalee and Colombo. Later in the same year, in a paper on "Some New or Rare Parasitic Copepods from the Indo-Tropical Region", he (Bassett-Smith, 1898 b) included three more species from Ceylon. Soon after, more of these parasites were obtained from Ceylon during Herdmann's investigation of the Pearl Banks. From this collection, one lot consisting of eleven species was described by Thompson and Scott (1903) and a second lot consisting of seven species was described by Wilson (1906). At that stage the number of species recorded from Ceylon made up to a total of twenty-eight and there the matter rested for another quarter of a century until, quite by chance, while collecting marine animals on a reef, Mr Kirtisinghe came across a newly dead half-beak with a learned parasite projecting from its body. Since then, in a number of occasional papers (Kirtisinghe, 1932-35, 1937, 1950, 1956, 1960) he has described thirty-eight more species of parasitic copepods from Ceylon. However, his collection included many more species which were put aside for later attention. In the present paper, while dealing with those forms in his collection which he has not recorded or described earlier, he has put together all the known forms of parasitic copepods of fish from Ceylon. A list of the host fishes with their respective parasitic copepods is also provided, types of new species, at present in the author's private collection, will be deposited in the Fisheries Department, Colombo, Ceylon.

Fish species diversity in the Victoria and Kyoga lake basins: their conservation and sustainable use

Introduction of exotic fish species especially the Nile perch Lates niloticus, is believed to be responsible for the decline of fish species diversity in lakes Victoria, Kyoga and Nabugabo.About 60% of the haplochromine cichlids are thought to have become extinct from L. Victoria due to predation by the Nile perch. However there are many lakes satelite to the lakes Victoria and Kyoga basins which still have fish fauna similar to that of the main lakes. many of the satellite lakes are separated from the main lakes in, which Nile perch was introduced by extensive swamps that provide a barrier to Nile perch .A survey was carried out in a number of these satelite lakes and an inventory made of existing fish species. Their distribution and relative abundances were also determined. The lakes studied included Nawampasa, Nakuwa,Kawi Lamwa Gigate, Nyaguo, Agu, Nabugabo. Kayanja, Kaytigi, Mburo, Kachera and Wamala.Some habitats within the main lakes Victoria and Kyoga, especially those with rocky outcrops· and macrophyte cover that provide refugia for endangered species from Nile perch,were also surveyed) Various stations along the River Nile were also sampled to quantify the fish species that are still resent. Kyoga minor lakes were found to have the highest number of fish species especially of haplochromine cichlids. Many haplochromine trophic groups that were thought to be extinct from 1. Victoria still occur in these lakes.!Some of the satellite lakes, especially lakes Kayugi, Mburo and Kachera still contain .healili populations of oreochromis. I esculentus that could be used as brood stock in fish farming. Many of these lakes should .I ( I therefore be protected for conservation offish species diversity

The biology, ecology, distribution and conservation of some surviving native non-cichlid fish species of Lakes Victoria, Kyoga and Nabugabo

Prior to introduction of non-native fish species into Lakes Victor i a, Kyoga and Nabugabo, the three lakes suppor ted diverse fish fauna representing 13 families consisting of six cichlid genera and fifteen non-cichlid genera. There were about 50 non-cichlid species and over 300 cichlids consisting of mainly haplochromines (Graham 1929, worthington 1929, Greenwood 1960). Many of the species were commercially and scientifically important and provided a rich variety of protein source to choose from. Following introduction of the Nile perch and several tilapiines species, most of the native species were drastically reduced and some have apparently disappeared. The few remaining species appear to be restricted in distribution due to the presence of the Nile perch. They are mainly confined to refugia such as marginal macrophytes, rocky outcrops and small satellite lakes which are separated from the areas of introduction by swamps

Biological and physical interactions on a tropical island coral reef: Transport and retention processes on moorea, French Polynesia

The Moorea Coral Reef Long Term Ecological Research project funded by the US National Science Foundation includes multidisciplinary studies of physical processes driving ecological dynamics across the fringing reef, back reef, and fore reef habitats of Moorea, French Polynesia. A network of oceanographic moorings and a variety of other approaches have been used to investigate the biological and biogeochemical aspects of water transport and retention processes in this system. There is evidence to support the hypothesis that a low-frequency counterclockwise flow around the island is superimposed on the relatively strong alongshore currents on each side of the island. Despite the rapid flow and flushing of the back reef, waters over the reef display chemical and biological characteristics distinct from those offshore. The patterns include higher nutrient and lower dissolved organic carbon concentrations, distinct microbial community compositions among habitats, and reef assemblages of zooplankton that exhibit migration behavior, suggesting multigenerational residence on the reef. Zooplankton consumption by planktivorous fish on the reef reflects both retention of reef-associated taxa and capture by the reef community of resources originating offshore. Coral recruitment and population genetics of reef fishes point to retention of larvae within the system and high recruitment levels from local adult populations. The combined results suggest that a broad suite of physical and biological processes contribute to high retention of externally derived and locally produced organic materials within this island coral reef system. © 2013 by The Oceanography Society. All rights reserved.

Distributional patterns and community structure of Caribbean coral reef fishes within a river-impacted bay

This study examined how riverine inputs, in particular sediment, influenced the community structure and trophic composition of reef fishes within Rio Bueno, north Jamaica. Due to river discharge a distinct gradient of riverine inputs existed across the study sites. Results suggested that riverine inputs (or a factor associated with them) had a structuring effect on fish community structure. Whilst fish communities at all sites were dominated by small individuals (

Potential of fisheries restocking off the Algarve coast using aquaculture produced marine fish

Tese de dout., Ciências do Mar, da Terra e do Ambiente (Ecologia Marinha), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2012

Computer modelling and estimation of recruitment patterns of non-branching coral colonies at three sites in Wakatobi Marine Park, S.E. Sulawesi, Indonesia; implications for coral reef conservation

We have studied growth and estimated recruitment of massive coral colonies at three sites, Kaledupa, Hoga and Sampela, separated by about 1.5 km in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. There was significantly higher species richness (P<0.05), coral cover (P<0.05) and rugosity (P<0.01) at Kaledupa than at Sampela. A model for coral reef growth has been developed based on a rational polynomial function, where dx/dt is an index of coral growth with time; W is the variable (for example, coral weight, coral length or coral area), up to the power of n in the numerator and m in the denominator; a1……an and b1…bm are constants. The values for n and m represent the degree of the polynomial, and can relate to the morphology of the coral. The model was used to simulate typical coral growth curves, and tested using published data obtained by weighing coral colonies underwater in reefs on the south-west coast of Curaçao [‘Neth. J. Sea Res. 10 (1976) 285’]. The model proved an accurate fit to the data, and parameters were obtained for a number of coral species. Surface area data was obtained on over 1200 massive corals at three different sites in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. The year of an individual's recruitment was calculated from knowledge of the growth rate modified by application of the rational polynomial model. The estimated pattern of recruitment was variable, with little numbers of massive corals settling and growing before 1950 at the heavily used site, Sampela, relative to the reef site with little or no human use, Kaledupa, and the intermediate site, Hoga. There was a significantly greater sedimentation rate at Sampela than at either Kaledupa (P<0.0001) or Hoga (P<0.0005). The relative mean abundance of fish families present at the reef crests at the three sites, determined using digital video photography, did not correlate with sedimentation rates, underwater visibility or lack of large non-branching coral colonies. Radial growth rates of three genera of non-branching corals were significantly lower at Sampela than at Kaledupa or at Hoga, and there was a high correlation (r=0.89) between radial growth rates and underwater visibility. Porites spp. was the most abundant coral over all the sites and at all depths followed by Favites (P<0.04) and Favia spp. (P<0.03). Colony ages of Porites corals were significantly lower at the 5 m reef flat on the Sampela reef than at the same depth on both other reefs (P<0.005). At Sampela, only 2.8% of corals on the 5 m reef crest are of a size to have survived from before 1950. The Scleractinian coral community of Sampela is severely impacted by depositing sediments which can lead to the suffocation of corals, whilst also decreasing light penetration resulting in decreased growth and calcification rates. The net loss of material from Sampela, if not checked, could result in the loss of this protective barrier which would be to the detriment of the sublittoral sand flats and hence the Sampela village.

Effects of human activities on rocky shores of the Surf Coast Shire: scientific basis for management at the regional level

The Surf Coast Shire in regional Victoria contains some of the most spectacular coastline in Australia, running from Point Impossible in the east to just west of the resort town of Lorne. The Surf Coast Shire council is committed to ecologically sustainable tourism based on its coastal assets, including the important intertidal environments. The challenge for the Shire is to protect and enhance the biodiversity of its intertidal areas whilst allowing for their sustainable use as a critical component of the local economy. In order to do this the Council needed to identify the conservation values of intertidal areas within the shire and assess the impacts that current human use has on these values. The impacts of shellfish collecting on rocky shores were identified as an issue of particular concern. We have conducted a research project with the Shire to provide a scientific basis for management decisions. The principal aims of this project were to: (1) determine the patterns of human use of intertidal habitats; (2) measure the impacts of human usage on biological communities and species populations; and (3) to identify intertidal sites of regional conservation significance for the Surf Coast Shire. Surveys of human usage identified reef walking, looking in rock pools and fossicking as major uses of rocky shores within the Surf Coast. This poster reports the effects of this usage on gastropod populations of rocky shores within the Surf Coast Shire. A small proportion of visitors collected intertidal organisms. Shores were categorized as high or low use based on total numbers of people observed at each shore over the first year of the project. Mean size and catch per unit effort were compared for several gastropod species between high use and low use shores. The results presented here show that the populations of some gastropod species are of smaller mean size and less abundant on high use shores than on low use shores. There was also a noticeable difference in degree of effect detected between sandstone and mudstone shores. The implications of these results are briefly discussed in terms of management options available to the Shire.

Remotely sensed hydroacoustics and observation data for predicting fish habitat suitability

This paper investigates the use of using remotely sensed observation and full coverage hydroacoustic datasets to quantify habitat suitability for a marine demersal fish, the blue-throated wrasse. Because of issues surrounding the detection of species using remotely sensed video techniques, the application of presence-only techniques are well suited for modeling demersal fish habitat suitability. Ecological-Niche Factor Analysis is used to compare analyses conducted using seafloor variables derived from hydroacoustics at three spatial scales; fine (56.25 m²), medium (506.25 m²) and coarse (2756.25 m²), to determine which spatial scale was most influential in predicting blue-throated wrasse habitat suitability. The coarse scale model was found to have the best predictive capabilities with a Boyce Index of 0.80±0.26. The global marginality and specialization values indicated that, irrespective of spatial scale, blue-throated wrasse prefer seafloor characteristics that are different to the mean available within the study site, but exhibit a relatively wide niche. Although variable importance varied over the three spatial scale models, blue-throated wrasse showed a strong preference for regions of shallow water, close to reef, with high rugosity and maximum curvature and low HSI-B values. Generally the spatial patterns in habitat suitability were well represented in the Marine National Park compared to adjacent waters. However, some significant differences in spatial patterns were observed. Interspersion and Juxtaposition Indexes for unsuitable and highly suitable habitat were significantly smaller inside the Marine National Park, while the Mean Shape Index of unsuitable habitat in the Marine National Park was significantly larger.

Field evaluation of a suite of biomarkers in an Australian Tropical Reef Species, Stripey Seaperch (Lutjanus carponotatus) : Assessment of Produced Formation water from the Harriet A Platform

There is paucity of data regarding hydrocarbon exposure of tropical fish species inhabiting the waters near oil and gas platforms on the Northwest Shelf of Australia. A comprehensive field study assessed the exposure and potential effects associated with the produced water (PW) plume from the Harriet A production platform on the northwest shelf in a local reef species, Stripey seaperch (Lutjanus carponotatus). This field study was a continuation of an earlier pilot study which concluded that there were “warning signs” of potential biological effects on fish populations exposed to PW. A 10-day field caging study was conducted deploying 15 individual fish into 6 separate steel cages set 1-m subsurface at 3 stations in a concentration gradient moving away from the platform. A battery of biomarkers were evaluated including hepatosomatic index (HSI), total cytochrome P450, bile metabolites, CYP1A-, CYP2K- and CYP2M-like proteins, cholinesterase (ChE) activity, and histopathology of liver and gill tissues. Water column and PW effluent samples was also collected. Results confirmed that PAH metabolites in bile, CYP1A-, CYP2K-, and CYP2M-like proteins and liver histopathology provided evidence of significant exposure and effects after 10 days at the near-field site (~200 m off the Harriet A platform). Hepatosomatic index, total cytochrome P450, and ChE did not provide site-specific differences by day 10 of exposure to PW. CYP proteins were shown by principal component analysis (PCA) to be the best diagnostic tool for determining exposure and associated biological effects of PW on L. carponotatus. Using a suite of biomarkers has been widely advocated as a vital component in environmental risk assessments worldwide. This study demonstrates the usefulness of biomarkers for assessing the Harriet A PW discharge into Australian waters with broader applications for other PW discharges. This approach has merit as a valuable addition to environmental management strategies for protecting Australia’s tropical environment and its rich biodiversity.

Fish assemblages associated with oil industry structures on the continental shelf of north-western Australia

This study provides the first assessment of fish associations with oil and gas structures located in deep water (85-175 m) on Australia's north-west continental shelf, using rare oil industry video footage obtained from remotely operated vehicles. A diverse range of taxa were observed associating with the structures, including reef-dependent species and transient pelagic species. Ten commercially fished species were observed, the most abundant of which was Lutjanus argentimaculatus, with an estimated biomass for the two deepest structures (Goodwyn and Echo) of 109 kg.