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1.
The current rate of shark global exploitation and mortality is arguably so high under current management regimes that unless a renewed initiative is undertaken some species of shark will become effectively extinct. Current efforts to sustainably manage shark mortality are driven primarily by domestic laws in a few countries, big international non-governmental organizations (BINGOs) promoting environmental laws in the countries or regions where they exist, a handful of regional fisheries management organizations (e.g., IATTC and ICCAT), and inter-governmental organizations such as CITES. The absence of enforcement capability is often argued as the critical component in the failure to protect sharks from overexploitation. The remedy advanced here goes far beyond the need for stepped up enforcement, and calls for the creation of an entirely new international management regime, the International Commission for the Conservation and Management of Sharks (ICCMS). Such an agency could learn from the experiences of management bodies tasked with conservation of species biologically similar to sharks, such as the International Whaling Commission (IWC), to improve its efficacy. Critics have identified many organizational flaws that reduced the IWC’s effectiveness during its earliest years. Some of those flaws are examined here and remedies are suggested that an ICCMS could use to create a more effective management regime. The life histories of elasmobranches and large whales are compared to illustrate their similarities as a biological foundation for the selection of the IWC as a model.  相似文献   

2.
Brazil currently ranks as the 11th producer and 1st importer of shark meat around the world. Data available from the FAO software FishStatJ along with data from regional sources, such as governmental bulletins, scientific papers, gray literature and internet were revisited to identify the main issues surrounding pelagic shark fisheries, trade and consumption in the largest country in South America. Among the main findings, it was noted that Brazil has not properly collected fishery statistics since 2007, that many species of threatened sharks are freely landed and traded even though it is prohibited by local legislation and/or international recommendations (regional fisheries management organizations). The blue shark (Prionace glauca) is the most frequently recorded shark in the official bulletins and is currently a locally targeted species. Additionally, the significant imports of this species from 23 other countries that also provide fins for Asia has drawn attention in recent decades. Regarding consumption, shark is considered to be low-value seafood compared to more common fish, such as groupers and snappers, and most Brazilians actually do not know that they are eating sharks. At present, the proportion of threatened elasmobranchs (in which sharks are included) in Brazil (33%, of 145 species) exceeds the global rate identified for the group (25%), and, until the present moment, no measure related to the management of species has been implemented. As advice, Brazil urgently needs to restructure its fishery information collection systems, management strategies and to tighten sanitary and labeling regulations for the marketing of fish.  相似文献   

3.
In the Northeast Atlantic, elasmobranchs are a common bycatch in many fisheries, including demersal trawls, longlines, or gillnets and many countries do not have regulations or any control over the amount taken. In the Mid Atlantic, the Azores EEZ (Exclusive Economic Zone), small-scale fishing operations, artisanal and hook-and-line fishing methods are responsible for part of local total landed elasmobranch biomass, although some species are specifically focused and severely harvested by international large-scale fleets. This work provides a review and analysis of the commercial elasmobranch fisheries in the Azores EEZ, and its evolution over the last two decades, highlighting management priorities, taking into account the Northeast Atlantic elasmobranch fisheries status. In the Mid-Atlantic, elasmobranch fisheries mainly target 4 species, that are usually landed as bycatch: the tope shark (Galeorhinus galeus) and the thornback ray (Raja clavata), captured mainly by local demersal artisanal fisheries, the blue shark (Prionace glauca) and the shortfin mako shark (Isurus oxyrinchus) captured by a more industrialised fleet, including those from foreign nations. Considering elasmobranchs life history traits and fishery history, caution is advised in the development of a management strategy focusing on these species, considering the Northeast Atlantic context and regional, local and national interests.  相似文献   

4.
Illegal shark fishing is thought to occur globally, including within so-called “shark sanctuaries”, marine reserves and even inside UNESCO World Heritage sites, such as the Galápagos Islands. Presumably, this is due to poor local enforcement coupled with the growing international demand (and high economic incentives) for shark and other wildlife products. Understanding illegal shark fishing practices, and specifically catch composition, is important as poaching is identified as a causal factor of global declines in shark populations. Unfortunately, reliable quantitative data on illegal shark fishing are scarce. Here, the catch onboard an illegal shark fishing vessel seized within the borders of the Galápagos Marine Reserve was documented. A total of 379 sharks from seven shark species were found onboard the vessel. A large fraction of the illegal catch was comprised of both female and juvenile sharks (64% and 89%, respectively). Despite numerous recent advances in shark conservation worldwide, this study demonstrates illegal shark fishing is an ongoing concern and that stricter enforcement and legislation is urgently needed, particularly in areas of high biodiversity.  相似文献   

5.
Sharks are threatened from overfishing due to their life cycle biology, and unsustainably high catch rates to supply fins for shark fin soup. Canada, a leader in shark conservation uses numerous legislative tools to help conserve sharks. These tools include international treaty obligations under the Northeastern Atlantic Fisheries Organization [NAFO] and the International Commission for the Conservation of Atlantic Tuna [ICCAT], as well as national and provincial legislation including the Fisheries Act, Pacific and Atlantic Fisheries Regulations, and Coastal Fisheries Protection Act. Through the use of these legislative tools Canada has successfully banned shark finning in its waters, and implemented closed seasons, gear restrictions, and species restrictions to help manage shark populations. However, Canada still allows the sale of shark fin products locally, and allows the exportation of shark fins internationally. In order for Canada to maintain its leadership status Canada must increase legislative protection of sharks by following international best practices, and ban the sale and exportation of shark fin products. This would ensure that Canada does not play a role in global supply or demand of shark fins. Doing so would strengthen Canada's position as a leader in shark conservation, and improve the legislation currently used as a conservation tool.  相似文献   

6.
Illegal, unreported and unregulated (IUU) fishing activities continue to thrive in the northern region of Australia's Fishing Zone (AFZ). Indonesian fishermen involved in IUU fishing in this area target specific marine species such as shark, reef fish, sea cucumber and trochus that are destined for the Asian market. Many of these marine species’ stocks are now at critical levels. Local communities based in Northern Australia, state and Federal governments are also concerned with issues of border security and quarantine measures that coincide with the IUU fishing activities. Whilst Australian and Indonesian governments continue to negotiate this pressing issue, international instruments, bilateral agreements and domestic policies are not deterring Indonesian fishermen from pursuing IUU fishing activities in the AFZ.  相似文献   

7.
Various species of sharks, skates, and rays continue to decline globally, demonstrating a greater need for effective conservation measures. In 1999 the Food and Agriculture Organization (FAO) developed comprehensive guidelines in its International Plan of Action for the Conservation and Management of Sharks (IPOA-sharks), which was followed by corresponding national plans in some nations. A case study of national implementation is presented here. Specifically, progress under Canada's National Plan of Action for Sharks (NPOA-sharks) is reviewed, against its stated goals, against Australia's NPOA, and against the original FAO guidelines. For comprehensiveness, additional management and conservation measures for sharks, as well as stakeholder input from the first Atlantic Shark Forum is provided. Although Canada is recognized as a leader in shark management, as it was one of the first countries to develop an NPOA, it has not effectively adopted the FAO's principles and guidelines. The plan lacks set timelines, priorities, and action plans to mitigate threats to sharks, and contains no performance indicators. Additionally, the plan neglects to identify priority species and engage stakeholders, and cannot be directly linked to management measures. To advance the revision of this plan (as well as other NPOAs), a stepwise process is recommended that includes (i) stakeholder engagement and development of a shark assessment report (SAR) (ii) addressing all IPOA objectives, while prioritizing issues arising from the SAR, and (iii) implementations of actions, targets, and timelines that are reviewed every four years. Key policy items to advance Canada's role in shark conservation and management are also presented. These include actions to improve data collection and research, management, and education, as well as coordination with stakeholders. In conclusion,major changes are needed to the existing NPOA to be fully effective and accountable. Likewise, the abovementioned measures may help guide more proactive plans in nations that have not yet established an NPOA.  相似文献   

8.
Adequate conservation and management of shark populations is becoming increasingly important on a global scale, especially because many species are exceptionally vulnerable to overfishing. Yet, reported catch statistics for sharks are incomplete, and mortality estimates have not been available for sharks as a group. Here, the global catch and mortality of sharks from reported and unreported landings, discards, and shark finning are being estimated at 1.44 million metric tons for the year 2000, and at only slightly less in 2010 (1.41 million tons). Based on an analysis of average shark weights, this translates into a total annual mortality estimate of about 100 million sharks in 2000, and about 97 million sharks in 2010, with a total range of possible values between 63 and 273 million sharks per year. Further, the exploitation rate for sharks as a group was calculated by dividing two independent mortality estimates by an estimate of total global biomass. As an alternative approach, exploitation rates for individual shark populations were compiled and averaged from stock assessments and other published sources. The resulting three independent estimates of the average exploitation rate ranged between 6.4% and 7.9% of sharks killed per year. This exceeds the average rebound rate for many shark populations, estimated from the life history information on 62 shark species (rebound rates averaged 4.9% per year), and explains the ongoing declines in most populations for which data exist. The consequences of these unsustainable catch and mortality rates for marine ecosystems could be substantial. Global total shark mortality, therefore, needs to be reduced drastically in order to rebuild depleted populations and restore marine ecosystems with functional top predators.  相似文献   

9.
Due to rapid declines of shark populations across many species and regions of the world, the need for large-scale conservation measures has become widely recognized. Some coastal states have opted to implement ‘Shark Sanctuaries’, which prohibit commercial shark fishing and the export of shark products across large areas, typically their entire Exclusive Economic Zones. Although shark sanctuaries cover almost as much area globally as marine protected areas (MPAs), their success has yet to be evaluated. Here, key features and regulatory details for eleven shark sanctuaries (covering 3% of global ocean area) are summarized, highlighting their commonalities and differences. Catch data are then used to shed light on the impact current shark sanctuaries could have on shark catch, foreign fleets, trade and abundance. Based on this comparative analysis, recommendations are made to implement program evaluation measures within existing and future shark sanctuaries that would explicitly outline goals and measures of success or failure. In summary, although shark sanctuaries may have the intended effect of reducing shark mortality, there appears a need to address bycatch within shark sanctuary regulations, and to collect baseline data that can be used to monitor sanctuary effectiveness.  相似文献   

10.
Internationally, shark conservation is now being recognized as a major environmental challenge, but management efforts to halt the overexploitation of sharks have lagged behind. This review examines the state of knowledge for shark species in Canadian waters and analyzes the role of existing management and legislation in ensuring shark conservation. Despite Canada's early leadership, the present management framework reveals major shortcomings with regard to legal protection, bycatch and finning regulations. These problems are not unique to Canada but illustrate broader issues pertaining to the global management of endangered fish species. To strengthen the conservation and management of sharks, this paper recommends a set of key policies and management priorities, which exemplify proper precautionary management of endangered shark species in Canada and could serve as a blueprint for improving conservation efforts internationally. A structured approach for grading progress in shark conservation efforts against best practices is also presented and could be used as a goalpost elsewhere.  相似文献   

11.
The major causes of large whale entanglement in South Africa are static fishing gear, especially the type associated with the West Coast rock lobster Jasus lalandii industry, and large-mesh gillnets that are set off the coast of KwaZulu-Natal (KZN) to reduce shark attacks (shark nets). The prevalence of entanglements is seasonal with the peaks in activity coinciding with the breeding migrations of humpback whales Megaptera novaeangliae and southern right whales Eubalaena australis, the two large whale species that are the most prone to entanglement. Generalised linear models with a Poisson or quasi-Poisson distribution were used to describe the relationship between the number of incidents and time. Taking into account the combined length of shark-net installations per year as an offset variable, entanglement of humpback whales in shark nets increased at 15.1% per year (95% CI = 9.5–21.6%) from 1990 to 2009. This is comparable to the rate of increase in the numbers of this species migrating past the KZN coast, between 1988 and 2002 (9–11%). The number of reported incidents of southern right whales entangled in gear other than shark nets also increased between 1990 and 2009. This was accounted for by the increase in numbers of this species in South Africa (7% per year), so in neither case are the two species at increasing risk of individual entanglement, and anthropogenic factors including entanglement do not seem to be affecting the recovery of these whale populations. Nevertheless, there is concern regarding the vulnerability to entanglement of a small assemblage of humpback whales that habitually visits the West Coast in spring and summer. The continued recovery of whale populations is likely to lead to greater levels of anthropogenic interaction and heighten the need for adequate mitigation measures. The KZN Sharks Board and the South African Whale Disentanglement Network (since 2006) have respectively released (disentangled) 81% and 23% of confirmed entangled individuals, and recorded relevant information on entanglement incidents. Such information is critical for developing mitigation measures and monitoring the prevalence of entanglement.  相似文献   

12.
The successful management of shark populations requires juvenile recruitment success. Thus, conservation initiatives now strive to include the protection of areas used by pre‐adult sharks in order to promote juvenile survivorship. Many shark species use inshore areas for early life stages; however, species often segregate within sites to reduce competition. Using a fisheries‐independent gillnet survey from the Northern Gulf of Mexico (2000–2010) we describe distribution patterns and preferred habitat features of the juveniles of six shark species. Our results suggest that multiple shark species concurrently use the area for early life stages and although they overlap, they exhibit distinct habitat preferences characterized by physical variables. Habitat suitability models suggest that temperature, depth, and salinity are the important factors driving juvenile shark occurrence. Within each site, across the sampled range of physical characteristics, blacktip shark (Carcharhinus limbatus) preferred higher temperature (>30 °C) and mid‐depth (~5.5 m); bonnethead shark (Sphyrna tiburo) preferred higher temperature (>30 °C) and mid‐salinity (30–35 PSU), finetooth shark (Carcharhinus isodon) preferred low salinity (<20 PSU) with mid‐depth (~4 m), scalloped hammerhead shark (Sphyrna lewini) preferred high temperature (>30 °C) and salinity (>35 PSU), Atlantic sharpnose shark (Rhizoprionodon terraenovae) preferred high temperature (>30 °C) and deep water (>6 m), and spinner shark (Carcharhinus brevipinna) preferred deep water (>8 m) and high temperature (>30 °C). The other investigated factors, including year, month, latitude, longitude, bottom type, inlet distance, coastline and human coast were not influential for any species. Combining habitat preferences with the sampled environmental characteristics, we predicted habitat suitability throughout the four sites for which physical characteristics were sampled. Habitat suitability surfaces highlight the differences in habitat use between and within sites. This work provides important insight into the habitat ecology of juvenile shark populations, which can be used to better manage these species and protect critical habitat.  相似文献   

13.
Despite the perilous status of many shark populations, rallying support for their conservation has been challenging, due in part to both long held negative perceptions and desire for shark fisheries. Recreational anglers are often advocates of conservation and can act as valuable partners with resource managers in developing fisheries management and conservation strategies. However, understanding their attitudes and perceptions, particularly towards resource status and management, is essential to developing successful management strategies and predicting outcomes. As a case study for assessing the complex challenges of sustainable shark fisheries, Florida recreational anglers were surveyed to understand how attitudes and perceptions influenced their willingness to donate for shark 1) conservation and protection or 2) fisheries sustainability. Overall, recreational angler willingness to donate was 25.5%, but attitudes and perceptions helped explain dramatic divides. For instance, willingness to donate was only 6% among the subset of anglers that perceived a growing large coastal shark population as a threat to recreational fishing opportunities. Highest support for shark conservation was shown by anglers who value seeing sharks in the wild (41.4%), and even more so among individuals who occasionally target sharks while fishing recreationally (65.8%). Pervasive among anglers unwilling to donate was a perception that shark populations were increasing, and thus not in need of further protection. These findings illustrate attitudes and perceptions that challenge shark conservation and fisheries management, as well as the critical importance of engaging anglers when developing strategies that rely on the recreational angling community for support.  相似文献   

14.
This study reports three interaction events between the whale shark (Rhincodon typus) and fisheries in Brazilian waters. Two events were described as incidental captures in a gillnet fishery on the northern coast of Rio de Janeiro State, in southeastern Brazil. The last event took place at the Royal Charlotte Oceanic Bank (RCOB), in the southern region of Bahia State, where five fishermen filmed their interaction with a juvenile specimen. For one of the incidental captures, the fish was landed and consumed by locals, and for the other, the shark was released. In the RCOB, the fishermen touched the whale shark with their hands, wooden sticks and even rode on it. In addition, 74 interviews were conducted with fishermen from Bahia about sightings and possible interactions with R. typus. According to statements made by the fishermen, although not frequent, the conduct reported for the RCOB occasionally takes place in the region. Evaluating information of this nature is important to support government plans that regulate fishing activities in order to reduce incidental captures and the harassment of whale sharks. Encouraging the participation of fishermen in a collaborative monitoring program for R. typus may be a good way to better understand the threats to the species at a reduced cost, particularly for developing countries, such as Brazil.  相似文献   

15.
The top-down effects of predators on ecosystem structure and dynamics have been studied increasingly. However, the nature and consequence of trophic interactions between upper-trophic-level predators have received considerably less attention. This is especially the case in marine systems due to the inherent challenges of studying highly mobile marine species. Here we describe the first documentation of asymmetrical intraguild predation by a pinniped predator on a mid-sized predatory shark. The report is based on direct observations in South African waters, in which free-swimming blue sharks Prionace glauca were captured and partially consumed by Cape fur seals Arctocephalus pusillus pusillus. These observations are important not just for understanding the interactions between these two species but more broadly for their implications in understanding the trophic ecology of pinnipeds, many populations of which have increased while numerous shark populations have declined.  相似文献   

16.
For several decades, fishing sharks for their fins has provided important livelihoods for eastern Indonesian coastal communities that fish the Halmahera, Arafura and Timor Seas. Fishery and interview data collected in 2012-13 from three case studies on the islands of Seram, Aru and Rote were used to examine changes in shark fishers’ livelihoods over the preceding 20 years. While recent declines in catches and shark fin prices have had a substantial impact on fishers’ livelihoods, the fishery's low visibility in some areas of its geographic range and its political complexity in general have meant that government and international development agencies have largely been unaware of this impact. Many respondents remembered the Asian Financial Crisis in 1997-98 and the turn of the millennium as a time when sharks were still abundant and shark fin prices high, but were concerned about the on-going fall of shark fin prices since March 2012. High-value species, particularly guitarfish, hammerhead and sandbar sharks were most affected, losing up to 40% of their pre-2012 value. These changes, combined with the loss of fishing grounds, few attractive options for alternative income and restrictive debt relationships with shark fin bosses, have led some fishers to resort to high-risk activities such as blast fishing, illegal transboundary fishing, and people smuggling. This paper examines the multi-layered causes and consequences of fishers’ decision-making in response to adverse changes in their fishery, and explores options and obstacles to pursuing livelihoods that carry lower environmental, financial and personal risks.  相似文献   

17.
Shark bite injuries on reef manta rays Manta alfredi off the coast of Inhambane, Mozambique, were examined over a three-year period (2003–2006). The frequency and seasonality of attacks, the rate of wound healing, and the possible identities of attackers were explored. This study presents the first examination of bite wounds on manta rays in the wild and the role sharks may play in the natural mortality of this species. The reported incidence of shark-inflicted injuries is high with over three-quarters of the sampled population affected. In total, 571 bite injuries were observed on 283 identified individuals. The number of bite injuries varied from one to seven, with a mean of 1.54 bite wounds. There was no significant difference in the frequency of bite injuries in male and female rays. The majority (96%) of the observed bite wounds were healed. Fresh wounds occurred throughout the year, with no obvious seasonality. The bull shark Carcharhinus leucas and tiger shark Galeocerdo cuvier are suggested as the primary mediators of attacks, although up to 11 other shark species are listed as potential attackers. The majority of the bite marks (96%) occurred to the most posterior region of the body, specifically the posterior edges of the pectoral and pelvic fins, with many injuries likely having a negative impact on the reproductive abilities and fitness of the rays.  相似文献   

18.
To properly manage world fisheries, especially highly migratory species, there are numerous treaties that have been implemented by specialized international fishery commissions. One of the oldest organizations is the International Commission for the Conservation of Atlantic Tunas (ICCAT). The main focus of this review was to summarize the history, roles and responsibilities of ICCAT, and to evaluate ICCAT's management of sharks in general and specifically for shortfin mako (Isurus oxyrinchus) shark. This review found that the Convention was established 40 years ago, but it was not until 2004 that the commission conducted its first population assessment on pelagic sharks.  相似文献   

19.
《Marine Policy》1998,22(3):209-215
The North and West African coastal and marine areas discussed in this paper consist of the countries from Morocco to Libya for North Africa, and from Morocco to South Africa (up to the Cape of Good Hope) in West Africa. These marine areas consist of a wide to narrow continental shelf, estuaries, lagoons, coastal plains, isolated mountains, mangroves and wetlands. These areas are centres of productive socio-economic activities with a high population density, vast fisheries, and mineral resources. Presently, these resources are exploited with little attention for the environmental consequences. Sustainable management of the marine environment and its resources requires effective management plans and a human capacity to formulate, implement and monitor these plans. However, most of the countries still lack funds, human and infrastructural capacity for the management of their marine territories and its resources. Though there are many universities, research institutes and private organisations with a modest infrastructure for both data and information handling and the management of the marine environment, the region still lags behind in human and infrastructural capacity. Existing capacity development programmes by United Nations agencies, governments, universities, nongovernmental agencies, have so far not been very effective. A vigorous marine capacity building effort is needed to ensure the sustainable management of the marine environment in this African region. Externally funded programmes with a focus ensuring technology cooperation are needed. Such programmes must be based on mutual co-operation and participation of scientists and administrators from the region at all levels of programme formulation, implementation and assessment.  相似文献   

20.
Shark interactions in pelagic longline fisheries   总被引：1，自引：0，他引：1  
Substantial ecological, economic and social problems result from shark interactions in pelagic longline fisheries. Improved understanding of industry attitudes and practices towards shark interactions assists with managing these problems. Information on fisher knowledge and new strategies for shark avoidance may benefit sharks and fishers. A study of 12 pelagic longline fisheries from eight countries shows that incentives to avoid sharks vary along a continuum, based on whether sharks represent an economic disadvantage or advantage. Shark avoidance practices are limited, including avoiding certain areas, moving when shark interaction rates are high, using fish instead of squid for bait and deeper setting. Some conventionally employed fishing gear and methods used to target non-shark species contribute to shark avoidance. Shark repellents hold promise; more research and development is needed. Development of specifically designed equipment to discard sharks could improve shark post release survival prospects, reduce gear loss and improve crew safety. With expanding exploitation of sharks for fins and meat, improved data collection, monitoring and precautionary shark management measures are needed to ensure that shark fishing mortality levels are sustainable.  相似文献   

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