1,665 research outputs found

    Temporal patterns of spawning and hatching in a spawning aggregation of the temperate reef fish Chromis hypsilepis (Pomacentridae)

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    Descriptions of temporal patterns in the reproduction of damselfishes (family Pomacentridae) and adaptive hypotheses for these patterns are derived mostly from studies of coral reef species. It is unclear whether the types of temporal patterns and the explanatory power of the adaptive hypotheses are applicable to damselfishes of temperate rocky reefs. This study tested hypotheses about the existence of lunar spawning cycles, the diel timing of hatching, and the synchronization of temporal patterns in hatching and tides in the schooling planktivorous damselfish Chromis hypsilepis on a rocky reef in New South Wales, Australia. Reproductive behaviour was observed daily for 223 days between August 2004 and March 2005. C. hypsilepis formed large spawning aggregations of 3,575-33,075 individuals. Spawning occurred at a uniform rate throughout the day on a semi-lunar cycle. The greatest number of spawnings occurred 1 day after the new moon and 1 day before the full moon. The cost to males from brood care was an 85% reduction in their feeding rate. The semi-lunar spawning cycle may be an outcome of the use of the lunar cue to synchronize the aggregation for spawning of widely dispersed individuals and the need for males to recuperate after brooding. Eggs hatched 3-7 h after sunset following a 4.5-day incubation period. This study provides no support for hypotheses that link temporal patterns in hatching with particular tidal regimes believed to facilitate early survival of larvae and their dispersal. The result that hatching occurred over the tidal cycle was due to the rapid off-reef dispersal of larvae from the spawning ground at all stages of the tide. C. hypsilepis is similar to other planktivorous damselfishes in its semi-lunar spawning cycle, cost of brood care, and protracted diel spawning regime. It differs in its lengthy period of hatching and its breeding in spawning aggregations, believed to be rare among demersally spawning fishes. © 2006 Springer-Verlag

    Requirements for marine protected areas to conserve the biodiversity of rocky reef fishes

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    1. This study describes spatial patterns in the biodiversity (species, assemblages) of rocky reef fishes at a spatial scale relevant to management, and compared the outcomes for this biodiversity from alternative procedures for selecting marine protected areas (MPAs) and from the selection of MPAs for fisheries-related objectives. 2. The study area included 104 species in two assemblage types; 36 species and 14 species occurred only in one or two locations respectively. 3. MPAs selected by hotspot richness, greedy richness complementarity, and summed irreplaceability included similar percentages of species and significantly more species than randomly selected MPAs. A combined species-assemblage selection ensured representation of assemblage diversity. Representation of all species and assemblage types required 92% of locations. 4. MPAs chosen using density of all fishes or density of exploitable fishes as selection criteria included fewer species (than MPAs selected using species identity) and the percentage of species accumulated did not differ from a random selection. 5. Use of an established MPA as the seed for an expanded network was inefficient, leading to additional locations being required and an accumulation of species that did not differ from a random selection. 6. The smallest MPA network that fulfilled multiple management objectives (representation of assemblage diversity and majority of species, population viability, support for fisheries, connectivity) required 30% of the surveyed locations. 7. This study concluded that: MPAs selected without the benefit of data on intra-habitat variation in species assemblages will be unrepresentative; the upper range of currently promoted targets for MPA establishment (i.e. 30%) should be regarded as a minimum for biodiversity conservation; MPAs selected for fisheries-related reasons may not provide expected benefits for the remainder of the fish assemblage. Copyright © 2006 John Wiley & Sons, Ltd

    The demographic and clinical characteristics of female veterans who engage in complementary and alternative medicine

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    Prior research has demonstrated that specific types of complementary and alternative medicine (CAM) are beneficial in decreasing mental health symptoms. Despite this, rates of CAM use are relatively low among veterans, and data about CAM use among female veterans is non-existent. Thus, the purpose of this study is to examine the demographic and clinical characteristics of female veterans that engage in CAM. Female Operation Enduring Freedom and Operation Iraqi Freedom Veterans (n=365) in Veterans Affairs (VA) care participated in a web-based survey that was one component of a larger VA study. Results indicated that slightly more than one third of female veterans engaged in CAM within the twelve months prior to participating in the study, and that exercise and movement therapy was the most commonly used CAM. Findings also revealed a variety of specific demographic and clinical characteristics of female veterans that engaged in CAM (i.e. identifying as Latino/Hispanic, having a service-connected disability rating, having private health insurance, needing mental health care in the past 6 months and being unable to get it, having experienced military sexual trauma, not receiving treatment since returning from deployment for drug and/or alcohol abuse, and not having been physically harmed by a stranger). These findings suggest that low rates of CAM use by female veterans may be due in part to cultural factors, cost, stigma, fear of risk-taking, and lack of health consciousness

    Impacts of docks on seagrass and effects of management practices to ameliorate these impacts

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    © 2013 Elsevier Ltd. Seagrasses have high conservation and human-use values, but around the world they are being damaged by human activities. Compared to the larger spatial scale at which some human activities affect estuaries and their seagrasses (e.g. catchment disturbance, dredging, pollution, trawling), recreational boating and infrastructure of moorings and docks act at smaller scales. However, the cumulative effects contribute to stresses acting on seagrass beds. This study assessed the effects of docks on the native seagrass Zostera muelleri subsp. capricorni in an estuary in south-east Australia and of current management practices designed to reduce dock impacts on this seagrass. A field survey found that seagrass biomass was significantly reduced below docks, and the effects were not influenced by dock orientation. Management practices requiring the use of a mesh decking to provide greater light penetration reduced, but did not eliminate, the reduction in seagrass biomass caused by docks. A modified beyond BACI experiment provided evidence for a causal link between the installation of wooden or mesh docks and reductions in biomass of seagrass. The reduction in biomass was apparent 6 mo after dock installation, and by 26 mo seagrass biomass had declined by at least 90%. Faced with increasing coastal populations, increases in recreational use, and continued pressures from other human activities, alternative management practices that further minimize the effects of docks are needed

    Changes in rocky reef fish assemblages throughout an estuary with a restricted inlet

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    Rocky reef habitat is common in many estuaries, yet its role as a habitat for fishes is poorly understood. There is also limited understanding of how access of coastal species into estuaries and habitat quality can affect the distribution of rocky reef fishes within estuaries. This study used baited remote underwater video stations to determine spatial patterns in fish assemblages associated with rocky reef habitat throughout a barrier estuary with a permanently open but restricted inlet. Estuarine rocky reefs provided habitat for a diverse assemblage of fishes, many of which were large juveniles and subadults. In the absence of a pronounced salinity or temperature gradient, a clear transition in fish assemblages occurred from coastal waters, through the inlet channel, to the central estuary, and into the inner estuary. The inlet channel, notably its narrowness and length, limits tidal input into this estuary, which acts as a significant impediment to the dispersal of many coastal fishes, and insufficient habitat excludes many coastal rocky reef species from the inner estuary. This study highlights the need to recognise estuarine rocky reefs as providing habitat for diverse fish assemblages and the role inlets play in restricting access of coastal species. © 2013 Springer Science+Business Media Dordrecht

    Spatial, temporal and ontogenetic variation in the association of fishes (family Labridae) with rocky-reef habitats

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    Habitat variability is an important factor structuring fish assemblages of rocky reefs in temperate Australia. Accepting the generality of this model requires that habitat-related variation is consistent through time, across multiple spatial scales, and applies to all life-history stages. We used repeated underwater visual surveys at multiple spatial scales over a 22-month period to test whether three distinct rocky-reef habitats had different wrasse assemblages and whether these assemblages were subject to spatial, temporal and ontogenetic variability. Overall, the strongest and most consistent habitat association was with sponge gardens, which had the most distinct assemblage, and the greatest species richness and density of individuals. Habitat associations in fringe and barrens were less consistent. A substantial increase in the abundance of small individuals, coinciding with warmer sea temperatures, contributed to temporal fluctuations in the density of wrasses. Overall, habitats were not strongly partitioned among larger individuals of the most abundant species, suggesting that adults are largely habitat generalists whereas small, recruiting individuals showed greater habitat specialisation. The present study emphasises the importance of incorporating spatial, temporal and ontogenetic variability into surveys of fish assemblages to understand more fully the dynamics of temperate rocky-reef systems. © CSIRO 2011

    Effects of pruning a temperate mangrove forest on the associated assemblages of macroinvertebrates

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    Mangrove forests around the world are being impacted by development in adjacent land and water areas. An after-control-impact study was undertaken to assess the effects of mangrove forest pruning on the associated benthic macroinvertebrate fauna. Pruning, undertaken 5 years before our sampling period, reduced the height of the forest canopy from 5 m to 1 m. Macrobenthic assemblages were sampled in September 2000 and January 2001 from two randomly selected sites within the pruned section of forest, and two sites in each of two control locations in the same forest. Assemblage composition in the pruned and undisturbed mangrove forests was not significantly different, nor were there significant differences in variability between the two areas. Similarity matrices for assemblages based on higher taxonomic groups and molluscs were highly correlated with similarity matrices for all taxa, indicating the utility of more rapid forms of assessment in this habitat. The results suggest that although short-term impacts may have occurred, no impact on macroinvertebrate assemblages was evident 5 years after the pruning

    Animal v. plant-based bait: Does the bait type affect census of fish assemblages and trophic groups by baited remote underwater video (BRUV) systems?

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    © 2016 The Fisheries Society of the British Isles. Coral reef fish communities were sampled at the Nayband Marine Park, Iran, using baited remote underwater video stations (BRUVSs) which incorporated animal (i.e. frigate tuna Auxis thazard and beef liver), or plant-based baits (i.e. raw dough and raw dough-turmeric powder mix). The A. thazard was found to record significantly (P < 0·05) higher species richness and number of carnivorous fishes than plant-based baits, while abundance of herbivores was maximum in raw dough-turmeric powder mix trials. There was also a significant difference in trophic composition of fish assemblages surveyed by animal- and plant-based baits which seemed to be due to variations in attraction patterns of carnivores and herbivores occurring at the earlier phases of each BRUV deployments. Meanwhile, the assemblage structure was comparable among fish assemblages sampled by different bait treatments, indicating that species-level responses to each bait type may be more complicated. In essence, the efficiency of mixed baits should also be examined in future studies

    Methods of social assessment in Marine Protected Area planning: Is public participation enough?

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    Addressing social and economic considerations is crucial to the success of Marine Protected Area (MPA) planning and management. Ineffective social assessment can alienate local communities and undermine the success of existing and future MPAs. It is rare to critique the success of methods used currently to incorporate social and economic considerations into MPA planning. Three Australian MPA planning processes covering three states and incorporating federal and state jurisdictions are reviewed in order to determine how potential social impacts were assessed and considered. These case studies indicate that Social Impact Assessment (SIA) is under-developed in Australian MPA planning. Assessments rely heavily on public participation and economic modelling as surrogates for dedicated SIA and are followed commonly by attitudinal surveys to gauge public opinion on the MPA after its establishment. The emergence of issues around public perception of the value of MPAs indicates the failure of some of these proposals to adequately consider social factors in planning and management. This perception may have potential implications for the long term success of individual MPAs. It may also compromise Australia's ability to meet international commitments for MPA targets to gazette at least 10% of all its marine habitats as MPAs. Indeed, this is demonstrated in two of the three case studies where social and economic arguments against MPAs have been used to delay or block the future expansion of the MPA network. © 2011 Elsevier Ltd
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