232,505 research outputs found
Movement of yellowtail snapper (Ocyurus chrysurus Block 1790) and black grouper (Mycteroperca bonaci Poey 1860) in the northern Florida Keys National Marine Sanctuary as determined by acoustic telemetry
We tagged a total of 14 yellowtail snapper (Ocyurus chrysurus Bloch 1790) and black grouper (Mycteroperca bonaci Poey 1860) inside the Conch Reef Research Only Area (a no-take marine reserve) in the northern Florida Keys National Marine Sanctuary in November 2001. Both species are heavily exploited in the region. Our objective was to characterize site fidelity and movement behavior along the reef tract to the north and south of the release point. Fishes were collected by baited hook and line from the surface, surgically-tagged with coded-acoustic transmitters, and returned to the reef by snorkelers. Tracking of fish movement behavior was conducted by five acoustic receivers deployed on the seafloor from Davis Reef in the south to Pickles Reef in the north. Fishes were tracked for up to eight months. Results indicated that the
majority of signal detections for individual fish from both species were recorded at the two Conch Reef receivers. Limited movement from Conch Reef to Davis Reef was recorded, but no signal detections were recorded at the two sites to the north of Conch Reef. These results suggest
that both species show site fidelity to Conch Reef. Future studies will seek to characterize this site fidelity with increased temporal and spatial resolution at Conch Reef. (PDF contains 25 pages.
Reef fishes of Saba Bank, Netherlands Antilles : Assemblage structure across a gradient of habitat types
Saba Bank is a 2,200 km2 submerged carbonate platform in the northeastern Caribbean Sea off Saba Island, Netherlands Antilles. The presence of reef-like geomorphic features and significant shelf edge coral development on Saba Bank have led to the conclusion that it is an actively growing, though wholly submerged, coral reef atoll. However, little information exists on the composition of benthic communities or associated reef fish assemblages of Saba Bank. We selected a 40 km2 area of the bank for an exploratory study. Habitat and reef fish assemblages were investigated in five shallow-water benthic habitat types that form a gradient from Saba Bank shelf edge to lagoon. Significant coral cover was restricted to fore reef habitat (average cover 11.5%) and outer reef flat habitat (2.4%) and declined to near zero in habitats of the central lagoon zone. Macroalgae dominated benthic cover in all habitats (average cover: 32.5 – 48.1%) but dominant algal genera differed among habitats. A total of 97 fish species were recorded. The composition of Saba Bank fish assemblages differed among habitat types. Highest fish density and diversity occurred in the outer reef flat, fore reef and inner reef flat habitats. Biomass estimates for commercially valued species in the reef zone (fore reef and reef flat habitats) ranged between 52 and 83 g/m2. The composition of Saba Bank fish assemblages reflects the absence of important nursery habitats, as well as the effects of past fishing. The relatively high abundance of large predatory fish (i.e. groupers and sharks), which is generally considered an indicator of good ecosystem health for tropical reef systems, shows that an intact trophic network is still present on Saba Bank
Connectivity between coastal habitats of two oceanic Caribbean islands as inferred from ontogenetic shifts by coral reef fishes
Mangroves and seagrass beds are considered important nursery habitats for juveniles of coral reef fishes. Studies have mostly focused on the fish community of just one habitat, so the connectivity between different coastal habitats is often unclear. In this study, density and size of reef fish were determined using a single sampling technique in four non-estuarine bay habitats and four reef zones in Curaçao and Bonaire (Netherlands Antilles). The data indicate that of the complete reef fish community at least 21 species show ontogenetic crossshelf shifts in habitat utilization. The 21 species mainly utilized shallow-water habitats (mangroves, seagrass beds, channel and shallow reef) as nursery habitats and the deeper coral reef zones (\u3e 5 m depth) as adult lifestage habitats. Fish species utilized 1–3 different nursery habitats simultaneously, but habitat utilization clearly differed between species. Previous studies showed that the dependence on these nursery habitats is very high, based on reduced density or absence of adults on coral reefs where these habitats were absent. The strong connectivity between several coastal habitats during the ontogeny of various commercially important reef fish species is evidence for the inclusion of bay habitats within boundaries of fishery reserves or marine protected areas
Grenada Carriacou Petite Martinique
The Eastern Caribbean Seascape is an arc of islands linked through diverse coral reef ecosystems, oceanic currents, migratory pathways and a rich cultural heritage. The Eastern Caribbean Coral Reef Report Cards are a series of individual reports for the6 participating countries and provide an easy-to-understand summary of the state of the region's marine resources. The Report Cards collate data from 277 comparable coral reef surveys and map in detail 383 km2 of coral reefs, 19 km2 of mangrove, 286 km2 of seagrass, 44 designated and 50 proposed Marine Managed Areas (MMA). The Report Cards provide an initial baseline on the current state of the reef and identify gaps. Reporting this type of information will help track progress in protecting reefs and inform future monitoring and management. The vision is to produce report cards every 2 years and share data through the CaribNode regional spatial data platform. Future report cards will include key socioeconomic and management effectiveness information. Each Report Card includes information on:Key Habitats (location and extent of coral, mangrove, seagrass)Reef Health Index (a measure of the health of four key coral reef indicators)Marine Managed Areas (size and location of designated and proposed areas
Current issues relating to artificial reefs in European seas
European artificial reef research has now been active for about three decades. For much of that time research has been conducted within national programmes, focussing on national or local issues, and has taken place predominately in the Mediterranean Sea. Over the past ten years or so interest in artificial reef technology and science has spread into the NE Atlantic and Baltic Sea with an associated variation in aims and ideas. Reef scientists working in European seas have run projects to assess artificial reefs as tools to protect habitat from destruction from trawling (Spain, Italy and France), promote nature conservation (Monaco, Italy and France), aid fisheries (Italy, Spain, Portugal and France), assess novel materials for reef construction (Italy and UK), investigate habitat use for lobsters (UK, Italy and Israel), for aquaculture (Italy), as experimental sites where habitat parameters are known (UK, Holland and Italy) and as biofiltration structures (Finland, Russia, Poland and Romania). This variety of investigation is one of the strengths of artificial reef research in Europe, the community is diverse and there is great scientific value in establishing collaboration and dialogue with colleagues.
The majority of artificial reef investigations have been, and still are, experimental with Italy dominating the research effort and Spain currently leading the way in the tonnage of reef material deployed, primarily for seagrass habitat protection. Problems associated with old descriptive, qualitative research have led to developments in quantification and comparative studies which have allowed a scientific perspective to be put on artificial reef deployments across Europe. Currently, as part of the EARRN (European Artificial Reef Research Network) initiative, there is an acceptance of the need to standardise some of the ecological methods used. If this is not practicable in some cases then at least the reporting of results will be done in such a way to allow comparison with data gathered elsewhere
Effects of Great Barrier Reef Degradation on Recreational Demand: A Contingent Behaviour Approach
Degradation of coral reefs may affect the number of tourists visiting the reef and, consequently, the economic sectors that rely on healthy reefs for their income generation. A Contingent Behaviour approach is used to estimate the effect of reef degradation on demand for recreational dive and snorkel trips, for a case study of the Great Barrier Reef (GBR) in Australia. We assessed how reef degradation affects GBR tourism and to what extent reef-trip demand depends on the visitors’ socio-economic characteristics. A count data model is developed, and results indicate that an average visitor would undertake about 60% less reef trips per year given a combined 80%, 30% and 70% decrease in coral cover, coral diversity and fish diversity, respectively. This corresponds to a decrease in tourism expenditure for reef trips to the Great Barrier Reef Marine Park of about A$ 136 million per year.Coral Reef, Recreation, Contingent Behaviour Model, Count Data Models
Stormwater Management Database for the City of Dover, New Hampshire
The overall goal of the project was to make a significant contribution to the Piscataqua Region Estuaries Partnership goal of increasing oyster (Crassostrea virginica) bottom in New Hampshire, and to do so using methods that positively affect multiple species. The focus was on those organisms (mainly macroalgae, invertebrates, and fish) that spend most of their time on oyster reefs—the resident species. A 0.5 hectare (1.25 acres) area was restored in August 2007 by constructing twelve mini-reefs (each ~6 m in diameter) in an area protected from harvest using spat-on-shell (“spat seeding”) from remotely set larvae. There was a consistent trend over time of higher oyster densities on the mini-reefs and on the natural reef within the protected area compared to the adjacent unprotected natural reef. At the end of the project period (1.8 years post-construction of the mini-reefs), total oyster densities in the overall restoration area were about 26% higher than the adjacent unprotected reef. The constructed mini-reefs also consistently had higher total densities and biomass of resident animals, which consisted mainly of invertebrates (only one fish was captured over the entire study), compared to the other reef areas. A total of 15 species of invertebrates were collected from the mini-reefs compared to 10 and 11 species, respectively, from the natural reef in the restored area and the natural reef in the harvested area. The resident (attached) macroalgae community patterns over time indicated higher biomass on the mini-reefs and the protected natural reefs compared to the unprotected reef area on most sampling dates, though there was typically wide variability among replicates. Macroalgal taxonomic richness was similar in all three areas, and there was a total of fourteen species collected from the three areas. Overall, the project resulted in enhancement of oyster reef habitat within the 0.5 hectare restoration area, and characterized the substantial value of oyster reefs in providing habitat for a variety of plant and animal species
Exploitation, secondary extinction and the altered trophic structure of Jamaican coral reefs
Coral reef communities of the Greater Antilles in the Caribbean have a long history of anthropogenic disturbance, driven by the exploitation for food of both vertebrate and invertebrate species. Exploitation, coupled with region wide declines of coral environments has resulted in local and regional vertebrate extinctions. The impact of those extinctions on reef communities, however, remains largely unexplored. Here we show, using a highly resolved model coral reef-seagrass food web, that at least 40 of 188 expected vertebrate species are absent from Jamaican coral reefs. Twenty one of the absent species are of high trophic level and are exploited by humans. The remainder of the absent species are unexploited, and comprises a significantly high proportion of specialized reef foragers. Many of those species are also more trophically specialized than their closest trophic competitors. We conclude that the absence of unexploited species from Jamaica is caused by the overexploitation of high trophic level species, and consequent trophic cascades and secondary extinction among their prey in an increasingly degraded reef environment. The result is a reef community depauperate of both exploited high trophic level predators, and unexploited, specialized lower trophic level reef foragers
Tahiti sea level : the last deglacial sea level rise in the South Pacific
Integrated Ocean Drilling Program (IODP) Expedition 310 to the reef terraces around Tahiti, French Polynesia, was the second expedition to utilize a mission-specific platform (MSP) and was conducted by the European Consortium for Ocean Research Drilling (ECORD) Science Operator (ESO). The objectives of Expedition 310 are to establish the course of postglacial sea level rise at Tahiti, to define sea-surface temperature (SST) variations for the region over the period 20–10 ka, and to analyze the impact of sea level changes on reef growth and geometry. To meet these objectives, the postglacial reef sequence, which consists of successive reef terraces seaward of the living barrier reef, was cored from a dynamically positioned vessel during October and November 2005. A total of 37 boreholes across 22 sites were cored in water depths ranging from 41.65 to 117.54 m. Borehole logging operations in 10 boreholes provided continuous geophysical information about the drilled strata. The cores were described during the Onshore Science Party at the IODP Bremen Core Repository during February and March 2006, where minimum and some standard measurements were made. Further postcruise research on samples taken during the Onshore Science Party are expected to fulfill the objectives of the expedition
St. Kitts and Nevis: Coral Reef Report Card 2016
The Eastern Caribbean Seascape is an arc of islands linked through diverse coral reef ecosystems, oceanic currents, migratory pathways and a rich cultural heritage. The Eastern Caribbean Coral Reef Report Cards are a series of individual reports for the6 participating countries and provide an easy-to-understand summary of the state of the region's marine resources. The Report Cards collate data from 277 comparable coral reef surveys and map in detail 383 km2 of coral reefs, 19 km2 of mangrove, 286 km2 of seagrass, 44 designated and 50 proposed Marine Managed Areas (MMA).The Report Cards provide an initial baseline on the current state of the reef and identify gaps. Reporting this type of information will help track progress in protecting reefs and inform future monitoring and management. The vision is to produce report cards every 2 years and share data through the CaribNode regional spatial data platform. Future report cards will include key socioeconomic and management effectiveness information.Each Report Card includes information on:Key Habitats (location and extent of coral, mangrove, seagrass)Reef Health Index (a measure of the health of four key coral reef indicators)Marine Managed Areas (size and location of designated and proposed areas
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