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Economic analysis of intensive black tiger organic shrimp culture: A case study of Amphoe Laem Sing Chanthaburi province
2011
Anuchit Thanawadee(Kasetsart University, Bangkok (Thailand). Faculty of Fisheries. Fisheries Management Department) | Varantut Dulyapruk(Kasetsart University, Bangkok (Thailand). Faculty of Fisheries. Fisheries Management Department) | Methee Kaewnern(Kasetsart University, Bangkok (Thailand). Faculty of Fisheries. Fisheries Management Department) | Wara Taparhudee(Kasetsart University, Bangkok (Thailand). Faculty of Fisheries. Department of Aquaculture)
Main objective of this research is to study factors affecting the intensive black tiger organic shrimp culture system. Data purposively collected from farm, farm owners in Laem Sing Chanthaburi Province. The analysis by multiple linear regression to show the relationship between organic and standard shrimp production factors used in pond management. The analytical result indicated that the intensive black tiger organic shrimp culture related to feed (X1), shrimp size (D1), stock density (D2), pH (D4) to shrimp production in a positive and salinity (X2) is related to shrimp production in a negative The returns to scale was 3.419 is in increasing returns to scale. The relationship between the output from the shrimp pond management factors should be added feed, size of shrimp, stock density, pH and lower salinity in the ponds will result in increased shrimp production.
Mostrar más [+] Menos [-]Building capacity for local planning Texto completo
2011
the worldfish center
When the administration of the fisheries sector in Cambodia was reformed, some roles and responsibilies, including cantonment planning, were delegated to the sub-national level. This was in line with the government's decentralization policy. However, the capacity of the fisheries cantonments to design their own plans is still limited. The Planning , Finance and International Co-operation Department of the FiA has initiated training courses. This fact sheet describes one training workshop delivered by the PFID | The WorldFish Center (2009) The Wetland Alliance. Fact sheet: working document no.0905. Cambodia. 1 p
Mostrar más [+] Menos [-]Status and recommendations on marine copepod cultivation for use as live feed Texto completo
2011
Drillet, Guillaume | Frouël, Stéphane | Sichlau, Mie H. | Jepsen, Per M. | Højgaard, Jonas K. | Joarder, Almagir K. | Hansen, Benni W.
Copepods are important crustaceans studied because of their key role in ecology, trophic biology, fisheries management, in modeling the flow of energy and matter, ecotoxicology, aquaculture and aquarium trade. This paper discusses various aspects of the state of knowledge of copepod culture at large scales and provides the scientific community with ideas and concepts that could improve and quicken the development of copepod mass cultures. As a framework for discussion, we use a conceptual scheme from Teece (1988) and adapted it to our goal: ‘how to capture value from a copepod product’. The suggestions include: 1) optimize cultures by automation and implement recirculation technology for improving water quality; 2) use harpacticoid and cyclopoid copepods in industries that can produce large amounts of these prey on site at any given time; but use calanoid copepods for industries limited in production time and those that export copepod products (e.g. eggs); 3) select preferentially local copepod species and if possible species with lipid conversion capabilities; 4) optimize sex ratio and selection/cross-breeding to develop suitable copepod strains for aquaculture; 5) explore the use of probiotics for improving the fitness of copepod cultures; and 6) encourage copepod producers/retailers to use/develop an efficient sales and marketing strategy.
Mostrar más [+] Menos [-]Fisheries mismanagement in a Natura 2000 area in western Greece Texto completo
2011
The impact of fisheries within a Natura 2000 area in western Greece was assessed over a 12-month period in 2007. The estimated total biomass removed annually by 307 fishing boats averaged 3503.5 t. Purse seiners, beach seiners and trawlers took 70% of the total landings. Purse seiners, contributing 3% of the total fishing fleet, were responsible for 33% of total biomass removed. Beach and purse seiners primarily caught small pelagic species, whereas trawlers and trammel netters mostly demersal species. A mismatch was found between the Common Fisheries Register (CFR) and an in situ assessment of the active fishing fleet; the number of industrial fishing boats exceeded those registered in CFR for the three administrative ports involved, and a large proportion of the CFR netters were small and effectively inactive. Fishery management measures for the recovery of an ecosystem considerably damaged by overfishing are proposed.
Mostrar más [+] Menos [-]Mesoscale structure and oceanographic determinants of krill hotspots in the California Current: Implications for trophic transfer and conservation Texto completo
2011
Santora, Jarrod A. | Sydeman, William J. | Schroeder, Isaac D. | Wells, Brian K. | Field, John C.
Krill (crustaceans of the family Euphausiacea) comprise an important prey field for vast array of fish, birds, and marine mammals in the California Current and other large marine ecosystems globally. In this study, we test the hypothesis that mesoscale spatial organization of krill is related to oceanographic conditions associated with coastal upwelling. To test this, we compiled a climatology of krill distributions based on hydroacoustic surveys off California in May–June each year between 2000 and 2009 (missing 2007). Approximately 53,000km of ocean habitat was sampled, resulting in a comprehensive geo-spatial data set from the Southern California Bight to Cape Mendocino. We determined the location and characteristics of eight definite and two probable krill “hotspots” of abundance. Directional-dependence analysis revealed that krill hotspots were oriented in a northwest–southeast (135°) direction, corresponding to the anisotropy of the 200–2000m isobath. Krill hotspots were disassociated (inversely correlated) with three upwelling centers, Point Arena, Point Sur, and Point Conception, suggesting that krill may avoid locations of strong offshore transport or aggregate downstream from these locations. While current fisheries management considers the entire coast out to the 2000m isobath critical habitat for krill in this ecosystem, we establish here smaller scale structuring of this critical mid-trophic level prey resource. Identifying mesoscale krill hotspots and their oceanographic determinants is significant as these smaller ecosystem divisions may warrant protection to ensure key ecosystem functions (i.e., trophic transfer) and resilience. Furthermore, delineating and quantifying krill hotspots may be important for conservation of krill-predators in this system.
Mostrar más [+] Menos [-]Effects of river temperature and climate warming on stock-specific survival of adult migrating Fraser River sockeye salmon (Oncorhynchus nerka) Texto completo
2011
MARTINS, EDUARDO G. | Hinch, Scott G. | Patterson, David A. | HAGUE, MERRAN J. | COOKE, STEVEN J. | MILLER, KRISTINA M. | LAPOINTE, MICHAEL F. | ENGLISH, KARL K. | FARRELL, ANTHONY P.
Mean summer water temperatures in the Fraser River (British Columbia, Canada) have increased by ∼1.5 °C since the 1950s. In recent years, record high river temperatures during spawning migrations of Fraser River sockeye salmon (Oncorhynchus nerka) have been associated with high mortality events, raising concerns about long-term viability of the numerous natal stocks faced with climate warming. In this study, the effect of freshwater thermal experience on spawning migration survival was estimated by fitting capture-recapture models to telemetry data collected for 1474 adults (captured in either the ocean or river between 2002 and 2007) from four Fraser River sockeye salmon stock-aggregates (Chilko, Quesnel, Stellako-Late Stuart and Adams). Survival of Adams sockeye salmon was the most impacted by warm temperatures encountered in the lower river, followed by that of Stellako-Late Stuart and Quesnel. In contrast, survival of Chilko fish was insensitive to the encountered river temperature. In all stocks, in-river survival of ocean-captured sockeye salmon was higher than that of river-captured fish and, generally, the difference was more pronounced under warm temperatures. The survival-temperature relationships for ocean-captured fish were used to predict historic (1961-1990) and future (2010-2099) survival under simulated lower river thermal experiences for the Quesnel, Stellako-Late Stuart and Adams stocks. A decrease of 9-16% in survival of all these stocks was predicted by the end of the century if the Fraser River continues to warm as expected. However, the decrease in future survival of Adams sockeye salmon would occur only if fish continue to enter the river abnormally early, towards warmer periods of the summer, as they have done since 1995. The survival estimates and predictions presented here are likely optimistic and emphasize the need to consider stock-specific responses to temperature and climate warming into fisheries management and conservation strategies.
Mostrar más [+] Menos [-]Ecosystem-based fisheries management in the Northwest Atlantic Texto completo
2011
Link, Jason S. | Bundy, Alida | Overholtz, William J. | Shackell, Nancy | Manderson, John | Duplisea, Daniel | Hare, Jon | Koen-Alonso, Mariano | Friedland, Kevin D.
The northwest Atlantic has had a notable history of living marine resource (LMR) exploitation. There have been calls for evaluating and improving approaches to manage those resources as stocks have undergone sequential depletion, with some dramatic instances of stock declines. The need for more holistic ecosystem-based approaches to manage LMRs has been increasingly recognized as part of these calls, along with the recognition that there are broader issues to consider when managing a fishery. We discuss some of the major efforts to this end which are extant among our institutions. We emphasize current initiatives to implement ecosystem-based fisheries management in the northwest Atlantic, with a focus on how advice based on the natural sciences supports an ecosystem-based approach. We present this information as a case study within a rich historical context of fisheries science and management.
Mostrar más [+] Menos [-]Overview of Management and Exploitation of the Fisheries Resources of Cameroon, Central West Africa Texto completo
2011
ENVIREP-CAM
This report discusses the present status of the Cameroon Fisheries regulation with respect to the United Nations Convention on the Law of the Sea (UNCLOS) and other International Conventions notably, the International Plan of Action-Illicit, Undeclared, Unregulated fishing (IPOA-IUU). It presents an overview of the fisheries resources of Cameroon analyzing fish production, management, exploitation, postharvest treatment, fish transport, commercialization and consumption. Major threats to sustainable exploitation and management are also herein discussed. Results reveal that the United Nations Convention on the Law of the Sea (UNCLOS) and other International Conventions do impose significant new commitments to the Cameroon fisheries legislation and that Cameroon will need to revise its legislation to meet international standards in ensuring sustainable use of marine living resources. The fisheries sector is dominated by foreigners (about 87%) and production has declined drastically to 1/6th its value of the 1970’s despite duplication of fishing effort (number of vessels). The postharvest sector is experiencing high post harvest losses (15%) mainly due to inadequate cold storage and processing facilities. There is absence of a management plan for the sector and management measures are limited to control of mesh sizes of some gears, limiting access to the coastal zone by industrial vessels to protect vulnerable coastal resources and reducing conflict. Monotitoring Control and Surveillance (MCS) activities are not well established resulting to low level implementation of the legislation in force and high levels of IUU, pollution, and use of inappropriate fishing gears and methods amongst others. Statistical data collection is fragmentary and there is no system in place for such activity. Research in the sector is suffering from poor financing and inadequate man power. After an analysis of all these issues, measures for sustainable exploitation and management are proposed. | Unpublished | fish production, fish management, fish exploitation, fish postharvest treatment, fish transport, fish commercialization, fish consumption
Mostrar más [+] Menos [-]Is the management procedure approach equipped to handle short-lived pelagic species with their boom and bust dynamics? The case of the South African fishery for sardine and anchovy Texto completo
2011
de Moor, Carryn L. | Butterworth, Douglas S. | De Oliveira, José A. A.
Worldwide, small shoaling pelagic fish manifest rapid and substantial natural changes in abundance. Is the application of a management procedure (MP), evaluated using simulation tests [i.e. a MP approach otherwise known as management strategy evaluation (MSE)], to recommend total allowable catches (TACs) with constraints desired by industry on the extent of interannual changes viable for such resources, particularly given the customarily lengthy MP evaluation process? This question is examined by considering the rapid boom and then bust situation that arose for the South African fishery for sardine (Sardinops sagax) and anchovy (Engraulis encrasicolus) across the turn of the century. Novel adaptations to the MP in place at the time of the boom allowed enhanced resource use during the boom period without compromising the risk of unintended depletion of the populations. Importantly a two-tier threshold system allowed the normal constraints on the maximum extent of interannual TAC reduction to be modified when TACs rose above the specified thresholds. The general protocol underlying the application of MPs for South African fisheries proved sufficiently flexible for the approach to continue to be applied, despite the unanticipated rapid fish population boom and then bust experienced.
Mostrar más [+] Menos [-]Impacts of spatial uncertainty on performance of age structure-based harvest strategies for blue eye trevalla (Hyperoglyphe antarctica) Texto completo
2011
Fay, Gavin | Punt, A. E. (André E.) | Smith, Anthony D.M.
Harvest control rules (HCRs), key components of fisheries management strategies, are used to calculate recommended catch levels given estimates of present stock biomass or levels of fishing mortality. Spatial variability, either in the population dynamics, fishery operations, or in data collection, has the potential to impact HCR performance as this can drive variability in indicators used for stock assessment. A management strategy evaluation (MSE) approach was used to evaluate the performance of HCRs for blue eye trevalla (Hyperoglyphe antarctica), a species that exhibits spatial variability in monitoring data in southeast Australia. Employing catch curve analysis, the HCRs rely solely on information from the age structure of the catch. Several versions of the HCRs were tested, varying the reference points used to determine management actions, and the way spatial variability was accounted for when setting catch limits. The results suggest that effective implementation of the HCRs is challenging, requiring appropriate choice of reference points and estimators. Spatial disaggregation of data leads to imprecise estimates of mortality rates. However, appropriate weighting of spatial estimates of stock status leads to higher relative stock size than when data are aggregated spatially. Variation in performance measures is dominated by uncertainty associated with mis-specification of the rate of natural mortality and the steepness of the stock–recruitment relationship. Such uncertainties can be expected for an information-poor, spatially heterogeneous resource, therefore additional considerations besides the HCR should be taken to achieve a desired precautionary result in contrast to the situation for more data-rich scenarios.
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