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C. Y. Burridge C. R. Pitcher T. J. Wassenberg I. R. Poiner B. J. Hill 《Fisheries Research》2003,60(2-3):237-253
We carried out a trawl-depletion experiment for benthic fauna in an area closed to commercial trawling. A 12-fathom prawn (shrimp) trawl net having a swept path of about 18 m was towed 13 times along each of six tracks. Each track was 2.7 km long and known from previous surveys to contain several relatively dense patches of megabenthos. The depletion rate was assumed to vary between trawls on a given track, and was modelled by a beta distribution defined by a mean rate and a dispersion parameter. Maximum likelihood analysis of the sequence of catches on each track suggests that a single trawl removes a small, but non-negligible, fraction of the benthos. The combined effect of 13 trawls on each track, assuming the trawls were aligned, was to remove a substantial proportion of the initial biomass. Gastropods suffered the greatest impact (an estimated 95% removed, on average). Ascidians, sponges, echinoids, crustaceans and gorgonians were depleted by an estimated 74–86%, and all other taxonomic groups except algae (27% removed) were reduced by at least 54%. Using differential global positioning systems and careful navigation, we aimed to achieve a high degree of overlap between successive trawls. Nonetheless, records show that the trawler deviated from this path and it is likely that the net did not sweep exactly the same path during the 13 trawls on each track. A simulation study was conducted to examine the effect on parameter estimates of ignoring the probable non-alignment of trawls. There was little bias in the estimate of the dispersion parameter. With the level of dispersion found on these tracks, the estimated mean depletion rates would, however, have been biased (upwards when the true mean depletion rate was below 15%, downwards when the true mean depletion rate was above 15%). This means that most mean depletion rates estimated from the catch data are probably biased by 2–3%. The depletion rates estimated from this study may be acceptable in areas that are trawled infrequently or sparsely. However, the cumulative effect of frequent trawls in an area of high intensity trawling is likely to be substantial both in terms of organisms directly affected by trawling and indirectly due to attracting scavengers and removing refuge habitat for fish and other mobile organisms. 相似文献
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- Marine protected area (MPA) planning often relies on scientific principles that help ensure that an area selected for conservation will effectively protect biodiversity. Capturing ecological processes in MPA network planning has received increased attention in recent years. High‐resolution seafloor maps, which show patterns in seafloor bio‐physical characteristics, can support our understanding of ecological processes.
- In part, owing to a global lack of high‐resolution seafloor maps, studies that aim to integrate seascape spatial pattern and conservation prioritization often focus on shallow biogenic habitats with less attention paid to deeper benthic seascapes (benthoscapes) mapped using acoustic techniques. Acoustic seafloor mapping strategies yield the spatial information required to extend conservation prioritization research into these environments, making incorporating seafloor ecological processes into conservation prioritization increasingly achievable.
- Here, a new method is proposed and tested that combines benthoscape mapping, landscape ecology metrics and a conservation decision support tool to prioritize areas with structural and potential connectivity value in MPA placement. Using a case study in eastern Canada, benthoscape composition and configuration were quantified using spatial pattern metrics and integrated into Marxan.
- Results illustrate how large patches of seafloor habitat in close proximity to neighbouring patches can be preferentially selected when benthoscape configuration is considered. The flexibility of the method for including relevant spatial pattern metrics or species‐specific movement data is discussed to illustrate how benthic habitat maps can improve existing conservation planning methods and complement existing and future work to support marine biodiversity conservation.
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Clare Greathead Paolo Magni Jan Vanaverbeke Lene Buhl‐Mortensen Urszula Janas Mats Blomqvist Johan A. Craeymeersch Jennifer Dannheim Alexander Darr Steven Degraer Nicolas Desroy Annick Donnay Yessica Griffiths Ivan Guala Laurent Guerin Hayley Hinchen Celine Labrune Henning Reiss Gert Van Hoey Silvana N.R. Birchenough 《水产资源保护:海洋与淡水生态系统》2020,30(7):1253-1275
- There is concern across the International Council for the Exploration of the Sea (ICES) region that a consideration of vulnerable components and the wider support mechanisms underpinning benthic marine ecosystems may be lacking from the process of marine protected area (MPA) designation, management and monitoring.
- In this study, MPAs across six European ecoregions were assessed from a benthic ecology perspective. The study included 102 MPAs, designated by 10 countries, and focused on three aspects regarding the role of the benthos in: (i) the designation of MPAs; (ii) the management measures used in MPAs; and (iii) the monitoring and assessment of MPAs.
- Qualitative entries to a questionnaire based on an existing framework (EU project ‘Monitoring Evaluation of Spatially Managed Areas’, (MESMA) were collected by 19 benthic experts of the ICES Benthic Ecology Working Group. A pedigree matrix was used to apply a numerical scale (score) to these entries.
- The results showed clear differences in scores between ecoregions and between criteria. The designation‐phase criteria generally achieved higher scores than the implementation‐phase criteria. Poor designation‐phase scores were generally reiterated in the implementation‐phase scores, such as scores for assessment and monitoring.
- Over 70% of the MPA case studies were found to consider the benthos to some extent during selection and designation; however, this was not followed up with appropriate management measures and good practice during the implementation phase.
- Poor spatial and temporal coverage of monitoring and ineffective indicators is unlikely to pick up changes caused by management measures in the MPA. There is concern that without adequate monitoring and adaptive management frameworks, the MPAs will be compromised. Also, there could be an increased likelihood that, with regard to the benthos, they will fail to meet their conservation objectives.
- This assessment was successful in highlighting issues related to the representation and protection of the benthos in MPAs and where changes need to be made, such as expanding the characterization and monitoring of benthic species or habitats of interest. These issues could be attributable to an ongoing process and/or an indication that some MPAs only have ‘paper protection’.
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