共查询到20条相似文献，搜索用时 31 毫秒
1.
- The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (>50 kg) in remote monsoonal rivers.
- Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records.
- Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes.
- Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries.
- The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.
2.
- Mahseer (Tor spp., Cyprinidae) are iconic, large-bodied, migratory freshwater fishes of Asian rivers. Long valued as a food source and serving other societal roles, these fishes are severely threatened by a broad range of interacting and escalating human impacts, including dam construction, water pollution, over-exploitation, and habitat destruction. Mahseer fishes are therefore beneficial to people, both directly and as indicators of ecosystem functionality and the associated ecosystem service benefits provided by the rivers that they inhabit.
- A literature review demonstrated that wild mahseer populations have a direct role in 11 of the 36 ecosystem services assessed and are indicative of a further 18 ecosystem services provided by the habitats that support them.
- Recognition of this range of ecosystem service benefits is helpful in describing to non-specialist public and policy-making communities the diversity of values provided by mahseer fishes and their supporting habitats, and hence the importance of their conservation.
- Assessment of the broad range of ecosystem services to which mahseer contribute is an approach that could usefully be applied to promote the benefits of conserving other ‘umbrella’ taxa and the habitats that support them.
3.
4.
Rebecca G. Martone Robin Naidoo Theraesa Coyle Bertine Stelzer Kai M.A. Chan 《水产资源保护:海洋与淡水生态系统》2020,30(6):1208-1219
- Facing public concern over costs related to top‐predator reintroductions and conservation, ecosystem services such as ecotourism are often used to evoke benefits that outweigh or offset those costs. Quantifying these benefits using rigorous scientific methods can provide confidence to policymakers and other stakeholders that predators can in fact deliver positive outcomes to people living alongside them. The evaluation of these benefits is often anecdotal or qualitative, however, and empirical quantifications are rare.
- In coastal marine ecosystems, sea otter reintroduction is seen as a conservation success to some but a bane to others. The contribution of sea otters (Enyhdra lutris) to tourism revenue is touted as a crucial ecosystem service benefit to offset the loss of shellfish harvesting and associated revenue, but remains unquantified, weakening the favourable reception of conservation action.
- The potential economic benefits of sea otters associated with tourism and the extent to which benefits are realized were evaluated based on: (i) choice‐experiment surveys of tourists; and (ii) interviews with tourism operators in British Columbia.
- Sea otters were a strong factor in people's choices regarding wildlife viewing, and sea otters could have large benefits for local economies. Alongside socio‐economic characteristics, tourism experience influences tourists’ preferences. Tourism operators did not perceive sea otters as strongly influencing tourist choice, highlighting the gap that can occur between the perception and the reality of tourist preferences, leading to missed opportunities for the alignment of economic development with conservation actions.
5.
Christina A.D. Semeniuk Wolfgang Haider Ben Beardmore Kristina D. Rothley 《水产资源保护:海洋与淡水生态系统》2009,19(2):194-208
- 1. Wildlife tourism can be prone to unmitigated development to promote visitor satisfaction that is all too often progressed at the cost of ecological integrity. A manager is thus faced with the dual task of enhancing the tourist experience and protecting the wildlife species. Accordingly, this mandate requires research into how tourists would respond to proposed wildlife‐management plans.
- 2. This study examines the heterogeneity of tourist preferences for wildlife management at a stingray‐feeding attraction in the Cayman Islands, using a latent class stated preference choice model. A sample of visitors to Stingray City Sandbar (SCS) evaluated hypothetical wildlife viewing experiences in a discrete choice experiment. Its scenarios were characterized by seven attributes such as animal‐feeding and handling rules, ecological outcomes, social crowding, and management cost (defined as a conservation access fee).
- 3. The latent class segmentation identified two groups in the population: approximately 68% preferred the implementation of fairly strict management rules, while the other 32% valued more the maintenance of status quo with its intensive human — wildlife interactions. Despite the differences between the ‘pro‐management’ and the ‘pro‐current’ segments, both exhibited a preference for the continuation of feeding and handling the stingrays (albeit at different levels of intensity) suggesting that one effective way to implement any management actions is to alter the promotional and marketing strategies for SCS. Other survey questions on trip experience, conservation values, and socio‐demographics were used to define these classes further, with the main distinguishing trait being the level of concern for potential impacts occurring at SCS. The discrepancies between the two segments became most obvious when calculating their respective market shares of support for alternative management strategies.
- 4. This approach to determining visitor preferences can help explain how the various segments will be affected by management options, and therefore can provide the basis for developing feasible strategies that will assist wildlife managers in maximizing tourist satisfaction while achieving wildlife‐protection goals.
6.
7.
- In 2016, the UK government announced plans for a large‐scale Marine Protected Area around Ascension Island, a UK Overseas Territory in the South Atlantic.
- To improve baselines for marine life to support ambitious conservation and assess change over time, archives were searched for historical accounts of wildlife from Ascension's discovery in 1501 to the present. For more recent changes, 139 interviews with past and present inhabitants were conducted.
- Ascension's marine life has, from first discovery to the present, been consistently remarked upon for its exceptional abundance. Historical sources indicate declines in seabird and turtle populations from human exploitation and introduction of rats and cats. They are recovering with good management, although still below pre‐settlement abundance.
- Interviews with residents indicate more recent changes, notably declines in catch per unit of fishing effort at popular shore angling sites, a decline in yellowfin tuna (Thunnus albacares) and increase in Galapagos sharks (Carcharhinus galapagensis).
- What is very notable, however, based on the interviews, was that there was no temporal signal suggestive of recent systemic decline, in marked contrast to many parts of the world where recent wildlife declines have been pervasive and steep. Ascension represents a remarkable and immensely important centre of abundance in a sea of depletion and change, warranting full protection for all the island's waters.
8.
9.
10.
11.
Gary E. Davis 《水产资源保护:海洋与淡水生态系统》2005,15(1):71-89
- 1. Place‐based conservation strategies require that stewards know and understand the targeted ecosystems, restore impaired resources, protect the ecosystems, and connect people wholeheartedly to the places. Knowledge of ecosystem structure and functioning is the cornerstone of stewardship.
- 2. This paper describes the design, implementation, and application of an ecological monitoring programme in Channel Islands National Park, California, USA. Experience from this programme showed that monitoring ecological ‘vital signs’ was a quick, sure, and inexpensive way to discover and track ecosystem dynamics.
- 3. Monitoring ecological ‘vital signs’ determined status and trends of ecosystem integrity and established limits of normal variation of key ecosystem features. It also provided early warnings of situations that required intervention and helped frame research questions to determine chains of cause and consequence.
- 4. The strong influence and probabilistic nature of biological interactions in ecosystems precluded effective use of deterministic modelling to predict ecosystem behaviour accurately. Therefore, ongoing monitoring was required to increase knowledge of system dynamics reliably. The US National Park Service has begun to identify and monitor the ecological ‘vital signs’ in 32 networks of 270 parks.
12.
13.
14.
- 1. The ecological status of floodplain areas along the Austrian section of the Danube was assessed by an approach based on dragonfly surveys. Although this river section contains a relatively high portion of the river‐type‐specific alluvial floodplain areas, most of them are influenced by river regulation and damming.
- 2. A key element of the assessment procedure, which is oriented towards the new EC Water Framework Directive, is the Odonate Habitat Index.
- 3. Classification of ecological status is based on the comparison between the status quo and reference conditions derived from a historical situation minimally influenced by human activities.
- 4. Data from 408 sites from 14 investigation areas were used. Ten of the 14 areas were ranked in class II (‘good ecological status’) within the five‐tiered system, which is the level of ecological status targeted in the directive. One area corresponds to the reference condition (class I, ‘high ecological status’), and three areas do not meet the quality objective (class III, ‘moderate ecological status’). A total of 49 species were found along the whole section, which represents 82% of the river‐type‐specific reference list.
15.
- 1. Marine reserves can play an important role in the conservation of subpopulations of marine fish metapopulations. The population spatial structure of northern Atlantic cod of Newfoundland and Labrador has characteristics of a metapopulation. Subpopulations of northern Atlantic cod on the continental shelf were decimated by decades of overfishing, and have not recovered. The remaining northern cod are concentrated in coastal areas.
- 2. A Marine Protected Area (MPA) was established in Gilbert Bay, Labrador by the Government of Canada in 2005 to protect the bay's resident subpopulation of northern Atlantic cod. Conservation of Gilbert Bay cod will help protect the genetic diversity of the northern cod metapopulation.
- 3. Unlike some other MPAs, Gilbert Bay is not a harvest refugium or ‘no‐take’ reserve. Aboriginal subsistence fisheries for salmonids with a bycatch of cod are allowed in designated areas of the MPA. A recreational fishery for Atlantic cod by angling open to all people is under consideration. Management of the MPA must ensure that fishing activities do not endanger the local cod population.
- 4. The population dynamics of Gilbert Bay cod were simulated using an age‐structured Leslie matrix model to estimate the total mortality under various recreational fishing scenarios. The level of sustainable harvest by a recreational fishery depends on the natural mortality of the Gilbert Bay cod population, which is unknown. Therefore, there is risk in permitting a recreational fishery in the MPA.
- 5. There may be benefits to the northern cod metapopulation, if the Gilbert Bay subpopulation is allowed to rebuild to the carrying capacity of the bay. If the abundance of Gilbert Bay cod exceeds the level which the local marine ecosystem can support, some cod may emigrate from the bay and recolonize adjacent coastal areas. The potential for Gilbert Bay cod to recolonize continental shelf areas is less certain.
16.
Nishikant Gupta Mark Everard Prakash Nautiyal Ishaan Kochhar Kuppusamy Sivakumar Jeyaraj Antony Johnson Atul Borgohain 《水产资源保护:海洋与淡水生态系统》2020,30(2):394-401
- Mahseer (Tor) fish species are critical components of locally adapted freshwater food webs across the Indian Himalayan biodiversity hotspot; however, multiple human stressors compounded by climate change have significantly depleted their populations over recent decades.
- Mahseer species are now considered locally vulnerable or endangered in many regions. Hydropower projects in particular have fragmented populations, impairing genetic exchange, obstructing migratory paths, and changing the structure and functioning of riverine habitats, especially of formerly fast‐flowing rivers.
- Worryingly, a literature survey and group discussions reveal that the increasing spread of non‐native fish species further compounds threats to mahseer and overall freshwater ecology. A better understanding of the current distribution, habitat requirement, and dispersal of non‐native fish is therefore essential to manage the growing threats to mahseer in the Indian Himalayan region.
17.
18.
19.
20.
- Throughout human history, the ocean has occupied myriad cultural meanings, mythologies and practices, which were often founded on a notion of the sea as being so large and ‘powerful’ as to be immune to human impacts. These conceptions were grounded in observations from the surface or shoreline, and in periods when human activities in the ocean were more technologically and spatially limited than they are today.
- Advancements in science and technology have significantly altered how humans interact with and access the ocean, allowing exploration and exploitation of ocean areas and processes that were previously incomprehensible. This new capacity to understand and extract from the ocean might be expected to profoundly alter human relationships to it and conceptions of it.
- As public support and engagement with marine conservation and ‘blue economies’ stem from value and belief systems, future marine management will benefit from recognizing our historical marine relationships as context for changes in understanding, use, and the increasing environmental degradation faced by the ocean. This review focuses on perspectives of the ocean that have been held historically and queries their future persistence at this potential turning point in our relationship with the ocean.