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Currently indexing 10497 titles

Design or pragmatic evolution: applying ITQs in EU fisheries management

Citation Information: Van Hoof, L. Design or pragmatic evolution: applying ITQs in EU fisheries management. – ICES Journal of Marine Science, doi.10.1093/icesjms/fss189.

Abstract: Among the proposals for the 2012 revision of the EU Common Fisheries Policy, a strong case is made for the introduction of a system of rights-based management. The EU perceives individual fishing concessions as an important instrument for capacity management. We will use the introduction of individual tradable quotas in the management of the Dutch North Sea beam trawl fisheries as a case for exploring the effect of the introduction of such an instrument. The effect will be assessed in terms of reduction of fishing capacity in the Dutch beam trawl fleet and its economic and social impact. These Dutch experiences will be translated to the current debate on the reform of the EU Common Fisheries Policy. Especially, we will focus on the issues of "relative stability", the concentration of rights, and the effects on the small-scale fisheries sector. Some of the negative effects associated with individual tradable rights can be addressed through design. However, trying to maintain stability and counter perceived negative impacts on fishing communities will modify the effect of introducing individual fishing concessions.

Global Coordination and Standardisation in Marine Biodiversity through the World Register of Marine Species (WoRMS) and Related Databases

Citation Information: Costello MJ, Bouchet P, Boxshall G, Fauchald K, Gordon D, et al. (2013) Global Coordination and Standardisation in Marine Biodiversity through the World Register of Marine Species (WoRMS) and Related Databases. PLoS ONE 8(1): e51629. doi:10.1371/journal.pone.0051629

Abstract: The World Register of Marine Species is an over 90% complete open-access inventory of all marine species names. Here we illustrate the scale of the problems with species names, synonyms, and their classification, and describe how WoRMS publishes online quality assured information on marine species.

Within WoRMS, over 100 global, 12 regional and 4 thematic species databases are integrated with a common taxonomy. Over 240 editors from 133 institutions and 31 countries manage the content. To avoid duplication of effort, content is exchanged with 10 external databases. At present WoRMS contains 460,000 taxonomic names (from Kingdom to subspecies), 368,000 species level combinations of which 215,000 are currently accepted marine species names, and 26,000 related but non-marine species. Associated information includes 150,000 literature sources, 20,000 images, and locations of 44,000 specimens. Usage has grown linearly since its launch in 2007, with about 600,000 unique visitors to the website in 2011, and at least 90 organisations from 12 countries using WoRMS for their data management.

By providing easy access to expert-validated content, WoRMS improves quality control in the use of species names, with consequent benefits to taxonomy, ecology, conservation and marine biodiversity research and management. The service manages information on species names that would otherwise be overly costly for individuals, and thus minimises errors in the application of nomenclature standards. WoRMS' content is expanding to include host-parasite relationships, additional literature sources, locations of specimens, images, distribution range, ecological, and biological data. Species are being categorised as introduced (alien, invasive), of conservation importance, and on other attributes. These developments have a multiplier effect on its potential as a resource for biodiversity research and management. As a consequence of WoRMS, we are witnessing improved communication within the scientific community, and anticipate increased taxonomic efficiency and quality control in marine biodiversity research and management.

Rapid Northward Spread of a Zooxanthellate Coral Enhanced by Artificial Structures and Sea Warming in the Western Mediterranean

Citation Information: Serrano E, Coma R, Ribes M, Weitzmann B, García M, et al. (2013) Rapid Northward Spread of a Zooxanthellate Coral Enhanced by Artificial Structures and Sea Warming in the Western Mediterranean. PLoS ONE 8(1): e52739. doi:10.1371/journal.pone.0052739

Abstract: The hermatypic coral Oculina patagonica can drive a compositional shift in shallow water benthic marine communities in the northwestern Mediterranean. Here, we analyze a long-term, large-scale observational dataset to characterize the dynamics of the species' recent northward range shift along the coast of Catalonia and examine the main factors that could have influenced this spread. The variation in the distributional range of Oculina patagonica was examined by monitoring 223 locations including natural and artificial habitats along >400 km of coastline over the last 19 years (1992–2010). Abundance of the species increased from being present in one location in 1992 to occur on 19% of the locations in 2010, and exhibited an acceleration of its spreading over time driven by the join action of neighborhood and long-distance dispersal. However, the pattern of spread diverged between artificial and natural habitats. A short lag phase and a high slope on the exponential phase characterized the temporal pattern of spread on artificial habitats in contrast to that observed on natural ones. Northward expansion has occurred at the fastest rate (22 km year−1) reported for a coral species thus far, which is sufficiently fast to cope with certain climate warming predictions. The pattern of spread suggests that this process is mediated by the interplay of (i) the availability of open space provided by artificial habitats, (ii) the seawater temperature increase with the subsequent extension of the growth period, and (iii) the particular biological features of O. patagonica (current high growth rates, early reproduction, and survival to low temperature and in polluted areas). These results are indicative of an ongoing fundamental modification of temperate shallow water assemblages, which is consistent with the predictions indicating that the Mediterranean Sea is one of the most sensitive regions to global change.

Coverage, Diversity, and Functionality of a High-Latitude Coral Community (Tatsukushi, Shikoku Island, Japan)

Citation Information: Denis V, Mezaki T, Tanaka K, Kuo C-Y, De Palmas S, et al. (2013) Coverage, Diversity, and Functionality of a High-Latitude Coral Community (Tatsukushi, Shikoku Island, Japan). PLoS ONE 8(1): e54330. doi:10.1371/journal.pone.0054330

Abstract:

Background

Seawater temperature is the main factor restricting shallow-water zooxanthellate coral reefs to low latitudes. As temperatures increase, coral species and perhaps reefs may move into higher-latitude waters, increasing the chances of coral reef ecosystems surviving despite global warming. However, there is a growing need to understand the structure of these high-latitude coral communities in order to analyze their future dynamics and to detect any potential changes.

Methodology/Principal Findings

The high-latitude (32.75°N) community surveyed was located at Tatsukushi, Shikoku Island, Japan. Coral cover was 60±2% and was composed of 73 scleractinian species partitioned into 7 functional groups. Although only 6% of species belonged to the ‘plate-like’ functional group, it was the major contributor to species coverage. This was explained by the dominance of plate-like species such as Acropora hyacinthus and A. solitaryensis. Comparison with historical data suggests a relatively recent colonization/development of A. hyacinthus in this region and a potential increase in coral diversity over the last century. Low coverage of macroalgae (2% of the benthic cover) contrasted with the low abundance of herbivorous fishes, but may be reasonably explained by the high density of sea urchins (12.9±3.3 individuals m−2).

Conclusions/Significance

The structure and composition of this benthic community are relatively remarkable for a site where winter temperature can durably fall below the accepted limit for coral reef development. Despite limited functionalities and functional redundancy, the current benthic structure might provide a base upon which a reef could eventually develop, as characterized by opportunistic and pioneer frame-building species. In addition to increasing seawater temperatures, on-going management actions and sea urchin density might also explain the observed state of this community. A focus on such ‘marginal’ communities should be a priority, as they can provide important insights into how tropical corals might cope with environmental changes.

Community Change within a Caribbean Coral Reef Marine Protected Area following Two Decades of Local Management

Citation Information: Noble MM, van Laake G, Berumen ML, Fulton CJ (2013) Community Change within a Caribbean Coral Reef Marine Protected Area following Two Decades of Local Management. PLoS ONE 8(1): e54069. doi:10.1371/journal.pone.0054069

Abstract: Structural change in both the habitat and reef-associated fish assemblages within spatially managed coral reefs can provide key insights into the benefits and limitations of Marine Protected Areas (MPAs). While MPA zoning effects on particular target species are well reported, we are yet to fully resolve the various affects of spatial management on the structure of coral reef communities over decadal time scales. Here, we document mixed affects of MPA zoning on fish density, biomass and species richness over the 21 years since establishment of the Saba Marine Park (SMP). Although we found significantly greater biomass and species richness of reef-associated fishes within shallow habitats (5 meters depth) closed to fishing, this did not hold for deeper (15 m) habitats, and there was a widespread decline (38% decrease) in live hard coral cover and a 68% loss of carnivorous reef fishes across all zones of the SMP from the 1990s to 2008. Given the importance of live coral for the maintenance and replenishment of reef fishes, and the likely role of chronic disturbance in driving coral decline across the region, we explore how local spatial management can help protect coral reef ecosystems within the context of large-scale environmental pressures and disturbances outside the purview of local MPA management.

Effectiveness of Marine Protected Areas in Managing the Drivers of Ecosystem Change: A Case of Mnazi Bay Marine Park, Tanzania

Citation Information: AMBIO; DOI: 10.1007/s13280-012-0352-8

Authors: Milali Ernest Machumu, Amararatne Yakupitiyage

Abstract: Marine protected areas (MPAs) are being promoted in Tanzania to mitigate the drivers of ecosystem change such as overfishing and other anthropogenic impacts on marine resources. The effectiveness of MPAs in managing those drivers was assessed in three ecological zones, seafront, mangrove, and riverine of Mnazi Bay Marine Park, using Participatory Community Analysis techniques, questionnaire survey, checklist and fishery resource assessment methods. Eleven major drivers of ecosystem change were identified. Resource dependence had a major effect in all ecological zones of the park. The results indicated that the park’s legislations/regulations, management procedures, and conservation efforts are reasonably effective in managing its resources. The positive signs accrued from conservation efforts have been realized by the communities in terms of increased catch/income, awareness and compliance. However, some natural and anthropogenic drivers continued to threaten the park’s sustainability. Furthermore, implementation of resource use and benefit sharing mechanisms still remained a considerable challenge to be addressed.

Tracking the long-distance dispersal of marine organisms: sensitivity to ocean model resolution

Citation Information: J. R. Soc. Interface; 6 April 2013; vol. 10, no. 81, 20120979

Authors: Nathan F. Putman, and Ruoying He

Abstract: Ocean circulation models are widely used to simulate organism transport in the open sea, where challenges of directly tracking organisms across vast spatial and temporal scales are daunting. Many recent studies tout the use of ‘high-resolution’ models, which are forced with atmospheric data on the scale of several hours and integrated with a time step of several minutes or seconds. However, in many cases, the model's outputs that are used to simulate organism movement have been averaged to considerably coarser resolutions (e.g. monthly mean velocity fields). To examine the sensitivity of tracking results to ocean circulation model output resolution, we took the native model output of one of the most sophisticated ocean circulation models available, the Global Hybrid Coordinate Ocean Model, and averaged it to commonly implemented spatial and temporal resolutions in studies of basin-scale dispersal. Comparisons between simulated particle trajectories and in situ near-surface drifter trajectories indicated that ‘over averaging’ model output yields predictions inconsistent with observations. Further analyses focused on the dispersal of juvenile sea turtles indicate that very different inferences regarding the pelagic ecology of these animals are obtained depending on the resolution of model output. We conclude that physical processes occurring at the scale of days and tens of kilometres should be preserved in ocean circulation model output to realistically depict the movement marine organisms and the resulting ecological and evolutionary processes.

Canada’s international and national commitments to sustain marine biodiversity

Citation Information: Environmental Reviews, 2012, 20(4): 312-352, 10.1139/a2012-013

Authors: David L. VanderZwaag, Jeffrey A. Hutchings, S. Jennings,c Randall M. Peterman

Abstract: Canada has made numerous international and national commitments to sustain marine biodiversity. International commitments include the implementation of ecosystem-based management, the establishment a network of marine protected areas, and the restoration of commercially exploited fish stocks. However, the international commitments tend to be quite general in nature with the precise governance implications of key principles, such as precaution and the ecosystem approach, being open to interpretation, thus leaving considerable room for discretion in implementation. Consequently, a plethora of soft law documents has emerged to provide more specific guidance to decision-makers and progressively develop international law and policy. Nationally, Canada has embraced a long list of commitments that are supportive of sustaining marine biodiversity through legislation and numerous policy-related documents. Nonetheless, Canada has left many of these commitments unfulfilled or inadequately fulfilled, such as (i) the development of integrated management plans for coastal and marine waters, (ii) the implementation of the precautionary approach for Canada’s fisheries, and (iii) the establishment of recovery strategies and identification of critical habitat for species at risk. Although the goal of effective protection of marine biodiversity in Canada appears to be guided by international and national commitments, there remains a clear need to fully implement, operationalize, and strengthen these commitments as articulated in the Oceans Act, fisheries management-related policies, the Species at Risk Act, and others.

Is Canada fulfilling its obligations to sustain marine biodiversity? A summary review, conclusions, and recommendations

Citation Information: Environmental Reviews, 2012, 20(4): 353-361, 10.1139/er-2012-0049

Authors: Jeffrey A. Hutchings, Isabelle M. Côté, Julian J. Dodson, Ian A. Fleming, S. Jennings, Nathan J. Mantua, Randall M. Peterman, Brian E. Riddell, Andrew J. Weaver, David L. VanderZwaag

Abstract: Canada has made numerous national and international commitments to sustain marine biodiversity. Given current and potential threats to biodiversity from climate change, fisheries, and aquaculture, we provide a summary review of Canada’s progress in fulfilling its obligations to protect, conserve, recover, and responsibly exploit marine biodiversity. We conclude that Canada has made little substantive progress, when compared to most developed nations, in meeting its biodiversity commitments. Much of Canada’s policy and rhetoric has not been operationalised, leaving many of the country’s national and international obligations unfulfilled in some key areas, such as the establishment of marine protected areas and incorporation of the precautionary approach to fisheries management. We conclude that regulatory conflict within Canada’s Department of Fisheries and Oceans (DFO) and the absolute discretion exercised by the national Minister of Fisheries and Oceans contribute significantly to an unduly slow rate of policy and statute implementation. We recommend new approaches and measures to sustain Canadian marine biodiversity and new research initiatives to support scientific advice to decision-makers. Many recommendations focus on management actions required to meet existing commitments to biodiversity conservation. Overall, we conclude that the most effective strategy is to protect existing biological diversity and to rebuild depleted populations and species to restore natural diversity. By improving and protecting the biodiversity in Canada’s oceans, such a strategy will restore the natural resilience of Canada’s ocean ecosystems to adapt to the challenges posed by climate change and other anthropogenic activities with consequent long-term benefits for food security and social and economic well-being.

Modelling the effects of reserve size and fishing mortality for Caribbean queen conch Strombus gigas

Citation Information: Aquatic Conservation: Marine and Freshwater Ecosystems; Volume 22, Issue 6, pages 721–730, September 2012

Authors: Jennifer Hernandez-Lamb, Anthony Dibello, Shelley Lewis, Gail Mackin, Kevin Kirby, Charles Acosta

Abstract:

  1. Overfishing has led to declines in many populations of Caribbean queen conch Strombus gigas, leading to its listing on CITES Appendix II. No-take marine protected areas (MPA) are increasingly being used as a conservation tool for protecting stocks and sustaining fisheries.
  2. A reaction–diffusion model was developed to study queen conch population responses to various sizes of MPAs, differing spatial and temporal fishing mortalities, and fluctuating recruitment rates. Movement behaviour and demographic data from a protected conch population at Glover's Reef, Belize, were used to parameterize the model and assess simulation results.
  3. The model predicted increases in density ranging from 300% in an MPA encompassing one-tenth of the total habitat area to 450% in an MPA encompassing half of the habitat, agreeing with field observations.
  4. Queen conch stock in the fishing zone was predicted to decline 6-40% with MPAs encompassing proportions of 0.1–0.5 of habitat area. Spillover estimated from conch movement was expected to reduce these losses and supplement the fishery by 2–4%.
  5. Sensitivity analysis of fluctuating recruitment showed that larger reserves can sustain population buildup even with lower recruitment rates. Relatively small increases in recruitment rates can potentially reduce fishing losses to 0 from MPA closures.
  6. Opening MPAs to fishing periodically or permanently is expected to rapidly deplete the conch population in a fraction of the time necessary for the initial buildup at the current fishing mortality rate.
  7. These results support those of previous modelling studies but also showed complex dynamics for this case study. While MPAs reduce the stock available to the fishery, spillover can supplement the fishery, and increases in recruitment could increase fishery yield beyond pre-MPA levels. With high fishing mortality, it would not be prudent to open MPAs to fishing for queen conch in any situation.

Heterogeneity in fishers' and managers' preferences towards management restrictions and benefits in Kenya

Citation Information: Environmental Conservation / Volume 39 / Issue 04 / December 2012, pp 357-369

Authors: TIMOTHY R. MCCLANAHAN, CAROLINE A. ABUNGE and JOSHUA E. CINNER

Abstract: Increasing the chances that resource users engage in and comply with management regulations is a continual problem for many conservation initiatives globally. This is particularly common when resource users perceive more personal costs than benefits from specific management actions. Analysis of interviews with managers and fishers from 22 landing sites along the coast of Kenya indicated how key stakeholders perceived the scale of benefits and costs from different management strategies. Potential underlying causes of divergent perceptions towards different management tools were evaluated, including marine protected areas, no-take fisheries closures, gear use, minimum size of fish caught and species restrictions. The analysis identified three distinct opinion groups: (1) a group of nine landing sites that scaled their preference for most management restrictions neutral to low, with exceptions for minimum sizes of captured fish and gear restrictions; (2) a group of eight landing sites that scaled their preference for the above and species restrictions and closed season higher, and were more neutral about closures and marine protected areas; and (3) a group containing four landing sites and the managers’ offices that rated their preference for the above and closed areas and marine protected areas as high. Logistic regression was used to examine whether these groups differed in wealth, education, age, perceptions of disparity in benefits, dependence on fishing and distance to government marine protected areas. The most frequent significant factor was the resource users’ perceived disparity between the benefits of the management to themselves and their communities, with the benefits to the government. Consequently, efforts to reduce this real or perceived disparity are likely to increase adoption and compliance rates. Most widespread positively-viewed restrictions, such as gear use and minimum size of fish, should be promoted at the national level while other restrictions may be more appropriately implemented at the community level.

Could European marine conservation policy benefit from systematic conservation planning?

Citation Information: Aquatic Conservation: Marine and Freshwater Ecosystems; Volume 22, Issue 6, pages 762–775, September 2012

Authors: Sylvaine Giakoumi, Stelios Katsanevakis, Vassiliki Vassilopoulou, Panayotis Panayotidis, Stefanos Kavadas, Yiannis Issaris, Athina Kokkali, Alexandros Frantzis, Aliki Panou, Georgia Mavrommati

Abstract:

  1. The Natura 2000 network of protected areas aims to assure the long-term survival of Europe's most valuable and threatened species and habitats. Yet, evidence shows that the present network fails to represent effectively the biodiversity of the region.
  2. Priority areas for conservation of coastal and offshore biodiversity features in the Greek Ionian Sea were identified, based on the principles of systematic conservation planning (SCP). SCP is a transparent method for the design of MPA networks and is considered more efficient and successful in representing the biodiversity of a region.
  3. The prioritization software Marxan was used and three scenarios with different sets of targets for 17 (high and low priority) conservation features were produced. These scenarios explicitly took into account socio-economic factors expressed as a single cost metric, weighting different economic sectors in proportion to their contribution to the GDP of the region. Then results were compared with the existing Natura 2000 sites in terms of goal achievement, area requirements, and cost.
  4. The solutions produced by the systematic approach demanded less area and lower cost to achieve the goals set, when the selection of all Natura 2000 sites was not forced. Existing Natura 2000 sites alone failed to achieve conservation goals for some EU priority and other important coastal and offshore habitats and species of the Mediterranean Sea.
  5. It is suggested that the use of systematic conservation planning and related computational tools could benefit the selection of European marine priority areas, especially in the context of ecosystem-based marine spatial management. Copyright © 2012 John Wiley & Sons, Ltd.

Marine protected areas and the value of spatially optimized fishery management

Citation Information: Proc Natl Acad Sci U S A. 2012 July 17; 109(29): 11884–11889.

Authors: Andrew Rassweiler, Christopher Costello, and David A. Siegel

Abstract: There is a growing focus around the world on marine spatial planning, including spatial fisheries management. Some spatial management approaches are quite blunt, as when marine protected areas (MPAs) are established to restrict fishing in specific locations. Other management tools, such as zoning or spatial user rights, will affect the distribution of fishing effort in a more nuanced manner. Considerable research has focused on the ability of MPAs to increase fishery returns, but the potential for the broader class of spatial management approaches to outperform MPAs has received far less attention. We use bioeconomic models of seven nearshore fisheries in Southern California to explore the value of optimized spatial management in which the distribution of fishing is chosen to maximize profits. We show that fully optimized spatial management can substantially increase fishery profits relative to optimal nonspatial management but that the magnitude of this increase depends on characteristics of the fishing fleet and target species. Strategically placed MPAs can also increase profits substantially compared with nonspatial management, particularly if fishing costs are low, although profit increases available through optimal MPA-based management are roughly half those from fully optimized spatial management. However, if the same total area is protected by randomly placing MPAs, starkly contrasting results emerge: most random MPA designs reduce expected profits. The high value of spatial management estimated here supports continued interest in spatially explicit fisheries regulations but emphasizes that predicted increases in profits can only be achieved if the fishery is well understood and the regulations are strategically designed.

Artificial Reef Effect in relation to Offshore Renewable Energy Conversion: State of the Art

Citation Information: ScientificWorldJournal. 2012; 2012: 386713; Published online 2012 December 23; doi: 10.1100/2012/386713

Author: Olivia Langhamer

Abstract: The rapid worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization, thus acting as artificial reefs. The artificial reef effect is important when constructing, for example, scour protections since it can generate an enhanced habitat. Specifically, artificial structures can create increased heterogeneity in the area important for species diversity and density. Offshore energy installations also have the positive side effect as they are a sanctuary area for trawled organisms. Higher survival of fish and bigger fish is an expected outcome that can contribute to a spillover to outer areas. One negative side effect is that invasive species can find new habitats in artificial reefs and thus influence the native habitats and their associated environment negatively. Different scour protections in offshore wind farms can create new habitats compensating for habitat loss by offshore energy installations. These created habitats differ from the lost habitat in species composition substantially. A positive reef effect is dependent on the nature and the location of the reef and the characteristics of the native populations. An increase in surface area of scour protections by using specially designed material can also support the reef effect and its productivity.

An adaptive framework for selecting environmental monitoring protocols to support ocean renewable energy development

Citation Information: The Scientific World Journal; Volume 2012 (2012), Article ID 450685, 23 pages; doi:10.1100/2012/450685

Authors: Emily J. Shumchenia, Sarah L. Smith, Jennifer McCann, Michelle Carnevale, Grover Fugate, Robert D. Kenney, John W. King, Peter Paton, Malia Schwartz, Malcolm Spaulding, and Kristopher J. Winiarski

Abstract: Offshore renewable energy developments (OREDs) are projected to become common in the United States over the next two decades. There are both a need and an opportunity to guide efforts to identify and track impacts to the marine ecosystem resulting from these installations. A monitoring framework and standardized protocols that can be applied to multiple types of ORED would streamline scientific study, management, and permitting at these sites. We propose an adaptive and reactive framework based on indicators of the likely changes to the marine ecosystem due to ORED. We developed decision trees to identify suites of impacts at two scales (demonstration and commercial) depending on energy (wind, tidal, and wave), structure (e.g., turbine), and foundation type (e.g., monopile). Impacts were categorized by ecosystem component (benthic habitat and resources, fish and fisheries, avian species, marine mammals, and sea turtles) and monitoring objectives were developed for each. We present a case study at a commercial-scale wind farm and develop a monitoring plan for this development that addresses both local and national environmental concerns. In addition, framework has provided a starting point for identifying global research needs and objectives for understanding of the potential effects of ORED on the marine environment.

Influences of Artificial Reefs on Juvenile Red Snapper Along the Mississippi Gulf Coast

Citation Information: Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science 5: 1-10. 2013

Authors: Jason R. Brandt and Donald C. Jackson

Abstract: Red Snapper Lutjanus campechanus represent one of the more economically important fisheries in the northern Gulf of Mexico; as such, Red Snapper abundance has decreased dramatically in the past two decades. The use of artificial reefs could aid in the rehabilitation of Red Snapper stocks by providing refuge for juveniles and a place of foraging and recruitment. A study was initiated to determine the effectiveness of different artificial reef distribution patterns in attracting and sustaining juvenile Red Snapper in the northern Gulf of Mexico. Fish traps (0.97 m long; 0.64 m high; funnel mouth size = 175 × 115 mm) were used to collect Red Snapper (<406 mm TL) that were associated with pyramid-shaped artificial reef structures (3.7-m triangular base; 2.4-m height; 3.2 metric tons) to evaluate two reef distribution designs: (1) five closely spaced pyramid units (“clumped” pattern) and (2) five closely spaced pyramids plus two sets of two pyramids at 30.5, 61.0, or 91.5 m from the five pyramids (“outlier” pattern). In 26 sampling trips, 927 Red Snapper were captured. Catch per unit effort (number of fish/trap soak-hour) did not differ significantly among artificial reef patterns (P = 0.396). Red Snapper TLs differed significantly among patterns (P = 0.005), with the largest mean TL (235 mm; SE = 5.14) occurring at the outlier pattern with 61.0-m spacing. Results from this study indicate that reef spacing and horizontal extension are important factors to consider when designing an artificial reef program, especially those that target juvenile Red Snapper.

Interactive exploration of movement data: A case study of geovisual analytics for fishing vessel analysis

Citation Information: Information Visualization; January 2013; vol. 12, no. 1, p. 65-84

Authors: René A Enguehard, Orland Hoeber, Rodolphe Devillers

Abstract: The analysis of large movement datasets is a challenging task, because of their size and spatial complexity. This paper presents an interactive geovisual analytics approach named Hybrid Spatio-Temporal Filtering that integrates filtering of multiple movement characteristics, geovisual representations of the data, and multiple coordinated views to enable analysts to focus on movement patterns that are of interest. In particular, we propose a novel technique that combines the fractal dimension and velocity of movement paths to filter out uninteresting records through an iterative signature-building process. In order to allow analysts to explore the data at different scales of the movement path length, fractal dimension estimation is performed using an adjustable moving window technique. These tools are provided in conjunction with a probability-based zonal incursion tool to visually represent when the movement nears areas of interest. The outcome is a geovisual analytics system that allows analysts to specify a hybrid filter consisting of the desired movement path complexity, the length of the paths to consider, and the velocity range that represents specific types of behaviors. This filtering of the data supports analysts in identifying movement paths that match their specified interests, resulting in a reduction in the amount of data shown to the analyst. The utility of the approach was validated through field trials, wherein fisheries enforcement officers analyzed and explored fishing vessel movement data using the prototype system. The participants responded positively to the features of the system and the support it provided for their data analysis activities. The combination of fractal dimension, velocity, and temporal filtering helped them to effectively identify subsets of data that conformed to particular behavioral patterns of interest.

Fishery management advice with ecosystem considerations

Citation Information: Lassen, H., Pedersen, S. A., Frost, H., and Hoff. A. Fishery management advice with ecosystem considerations. – ICES Journal of Marine Science, doi:10.1093/icesjms/fss208.

Abstract: The European Union Marine Strategy Framework Directive (MSFD) includes four descriptors of Good Environmental Status (GES) which are affected by fishing activity. These descriptors are: biodiversity, fish stocks, foodweb, and seabed integrity. This paper shows how these descriptors can be related to variables within an ecological model and how an ecological model can be used to analyse whether the fishing pressure that is estimated based on bioeconomic criteria is within general sustainable limits. The paper presents an example of such an analysis of the Eastern Baltic cod fishery using two models: a bioeconomic model and an ecological model. The models are calibrated based on historic data. The mapping between the descriptors specified by MSFD and variables available for analysis in the models is incomplete, e.g. genetics and spatial structures are not included in the models. The models can be used strategically, providing a qualitative understanding of the anticipated relative changes.

Quantifying the tradeoff between precaution and yield in fishery reference points

Citation Information: Hart, D. R. Quantifying the tradeoff between precaution and yield in fishery reference points. – ICES Journal of Marine Science, doi.10.1093/icesjms/fss204.

Abstract: A method using Monte Carlo simulations for estimating fishery reference points that accounts for parameter uncertainty is presented. Uncertainties in the input parameters of yield-per-recruit and stock-recruit analyses are propagated to estimate uncertainty in reference points such as FMSY. These uncertainties are used to evaluate the tradeoffs between the risks of overfishing and stock collapse, and the cost of reduced expected yield due to setting fishing mortality below FMSY. At fishing mortalities near FMSY, reduction in fishing mortality substantially decreases the probability of overfishing and stock collapse in exchange for slightly reduced expected yield. At lower fishing mortality rates, the marginal benefit (in terms of lessened risk of overfishing and stock collapse) from further reductions in fishing mortality is less, and the cost in forgone yield is greater. Less resilient “low steepness” stocks require additional precaution due to the risk of complete population collapse. Marine protected areas can also reduce risks of collapse, but at a higher cost in terms of expected yield than effort reduction. Implementation uncertainty (i.e. uncertainty in achieving a fishing mortality target) increases the risk of overfishing as well the loss of yield due to precaution, except at fishing mortalities near or above FMSY.

Model prediction vs. reality—testing the predictions of a European eel (Anguilla anguilla) stock dynamics model against the in situ observation of silver eel escapement in compliance with the European eel regulation

Citation Information: Prigge, E., Marohn, L., Oeberst R., and Hanel, R. Model prediction vs. reality—testing the predictions of a European eel (Anguilla anguilla) stock dynamics model against the in situ observation of silver eel escapement in compliance with the European eel regulation – ICES Journal of Marine Science, doi:10.1093/icesjms/fss188

Abstract: A direct monitoring of European silver eel (Anguilla anguilla, L) escapement from rivers and estuaries has been proven to be challenging, and a Europe-wide documentation of escaping silver eel numbers therefore hardly seems realistic. To reinforce management decisions, policy-makers are thus widely reliant on the accuracy of escapement models. A 3-year programme of silver eel escapement monitoring was undertaken to compile model input data and revise an eel population model (German Eel Model II; GEM II) already used in the decision-making process of management authorities. By compiling necessary input data and analysing vital system-specific population characteristics, it was possible to compare the documented silver eel escapement with the modelled potential silver eel escapement. Resulting model predictions were close to actually monitored escapement numbers, which were distinctly lower than reference escapement values for the same freshwater system given in the implementation report of the German Eel Management Plans. Applying different commercial and recreational catch scenarios revealed the sensitivity of the model. The results show the potential of the GEM II and highlight the importance of high-quality input data to use model predictions as the basis for management measures.

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