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- 1. The movement patterns of Australian and New Zealand fur seals trapped on salmon farms in south‐east Tasmania and relocated hundreds of kilometres away, were monitored using satellite telemetry. Australian fur seals released 470 km away by sea returned to farms after an average of 8.5±4.4 days (n=9 trips) and those released at 140 km returned after 3.2±0.8 days (n=4 trips). New Zealand fur seals (n=5 trips) averaged a return time of 6.8±1.2 days from 300 km.
- 2. When in south‐east Tasmania, both seal species undertook short trips to sea (mean 2.6 days) from haul‐out sites (minimum distance from farms 21 km) with 33% (1.8 days) of this time spent within 5 km of farms. Mean haul‐out duration was 1.1 days.
- 3. In summer, Australian fur seals repeatedly travelled between northern Bass Strait islands and southern Tasmanian waters following the Tasmanian east coast. Seals did not visit farms during this time.
- 4. Southern Tasmanian waters are important foraging grounds for fur seals and potential exists for a substantial number of seals to visit nearby fish farms. Farms provide predictable food resources from penned and escaped salmon, and wild fish attracted to the area.
- 5. Australian fur seals trapped at Tasmanian salmon farms regularly visited breeding colonies on islands in Victoria.
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- 1. Shellfish mariculture is increasing worldwide and often occurs adjacent to marine mammal breeding and feeding habitat. To better understand breeding pinniped vulnerability to potential shellfish mariculture disturbance and displacement effects in a US National Park, potential mechanisms were explored that may affect the proportion of harbour seals (Phoca vitulina) selecting high quality haul‐out sites near shellfish aquaculture within a large colony, and overall seal utilization of that colony in relation to other regional colonies.
- 2. Seal haul‐out sites isolated from the mainland (no predator access) had higher pup:adult ratios, indicating they are generally more important for pupping. Short‐term human disturbance did not have a significant effect on spatial use, but rather spatial use was pre‐determined by general sandbar isolation. Using multiple competing hypothesis and an information‐theoretic approach, it was found that within the estuary, after removing effects of El Niño, the proportion of seals (total seals and pups only) hauled out near mariculture sites was 8 ± 2% lower during years of higher oyster harvest. Annual oyster harvest was used as a measure of aquaculture activity that could result in direct disturbance or indirect displacement of harbour seals.
- 3. At the regional scale, oyster harvest, seal counts at a nearby colony, and loss of a major haul‐out site within the estuary, best explained pup and total seal use compared with the region. Regional population size, short‐term human disturbance rate, and other factors were not important. Concurrent with higher oyster harvest, the proportion of regional seals using the estuary declined by 7 ± 2% for seal pups (–65 ± 18 total pups), and 5 ± 2% for total counts ( ? 192 ± 58 total seals). These findings (both within the estuary and at the regional scale) were essentially identical whether modelling oyster harvest as either a continuous or categorical (low/high) variable and when using either frequentist or Bayesian statistical analyses.
- 4. Marine reserves set aside for wildlife may be less effective when the highest quality breeding and pupping sites are adjacent to regular aquaculture activities. These effects may not be detectable until additional natural variation lowers the quality of nearby habitats. Published in 2011. This article is a US Government work and is in the public domain in the USA.
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Site‐fidelity and movement patterns of bottlenose dolphins (Tursiops truncatus) in central Argentina: essential information for effective conservation 
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下载免费PDF全文 Els Vermeulen Alejandro Balbiano Florencia Belenguer Daniel Colombil Mauricio Failla Edgardo Intrieri Stefan Bräger 《水产资源保护:海洋与淡水生态系统》2017,27(1):282-292
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Karen Backe Ellen Hines Karina J. Nielsen Doug George Elinor Twohy Mark Lowry 《水产资源保护:海洋与淡水生态系统》2021,31(7):1749-1759
- Patterns and changes in the distribution of coastal marine mammals can serve as indicators of environmental change that fill critical information gaps in coastal and marine environments. Coastal habitats are particularly vulnerable to the effects of near-term sea-level rise.
- In California, Pacific harbour seals (Phoca vitulina richardii) are a natural indicator species of coastal change because of their reliance on terrestrial habitats, abundance, distribution, and site fidelity. Pacific harbour seals are marine top predators that are easily observed while hauled out at terrestrial sites, which are essential for resting, pupping, and moulting.
- Although increasing inundation from recent sea-level rise and storm-driven flooding has changed the Californian coastline, little is known about the effect of future sea-level rise and increased storm frequency and strength on harbour seal haulout site availability and quality in California.
- Harbour seal habitat was modelled at two sandbar-built estuaries under a series of likely sea-level rise and storm scenarios. The model outputs suggest that, over time, habitat at both estuaries decreased with increasing sea level, and storm-enhanced water levels contributed significantly to habitat flooding. These changes reflect pressures on coastal habitats that have an impact on human and natural systems.
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James R.A. Butler Stuart J. Middlemas Simon A. McKelvey Iain McMyn Ben Leyshon Ian Walker Paul M. Thompson Ian L. Boyd Callan Duck John D. Armstrong Isla M. Graham John M. Baxter 《水产资源保护:海洋与淡水生态系统》2008,18(6):1025-1038
- 1. Within the Moray Firth, north‐east Scotland, there is a history of conflict between seals and salmon fisheries. Under the UK's Conservation of Seals Act 1970 (CoSA) seals are shot to protect fisheries. In 1999 six rivers in the Moray Firth were designated as Special Areas of Conservation (SACs) for Atlantic salmon under the EU Habitats Directive, and in 2000 an SAC for harbour seals was designated in the Dornoch Firth.
- 2. In the 1990s salmon stocks declined. Fisheries managers believed the decline was partly caused by seal predation and consequently increased shooting effort. In years 1993–2003 Moray Firth harbour seal numbers declined possibly due to shooting, posing a potential threat to the status of the Dornoch Firth SAC. Meanwhile wildlife tourism based on marine mammals has increased. The declines in salmon and harbour seals, and the implementation of the Habitats Directive forced a watershed in the approach of statutory authorities to managing seals, salmon and tourism.
- 3. In years 2002–2005 local District Salmon Fishery Boards, the Scottish Executive, Scottish Natural Heritage and stakeholders negotiated a pilot Moray Firth Seal Management Plan to restore the favourable conservation status of seal and salmon SACs, and to reduce shooting of harbour seals and seal predation on salmon.
- 4. Key facets of the plan are the management of the Moray Firth region under a CoSA Conservation Order; application of the Potential Biological Removal concept to identify a limit of seals to be killed; management areas where removal of seals is targeted to protect salmon, while avoiding seal pupping and tourism sites; a training and reporting system for marksmen; a research programme, and a framework allowing an annual review of the plan.
- 5. The plan was introduced in April 2005. A maximum limit of 60 harbour and 70 grey seals was set. Forty‐six harbour and 33 grey seals were killed in 2005 while in 2006 these figures were 16 and 42 respectively. Although the numbers killed were below the maximum limits in both years the returns raised questions about the plan's ability to manage seal shooting at netting stations. The plan provides a useful adaptive co‐management framework for balancing seal and salmon conservation with the protection of fisheries and/or fish farms and tourism for application in the UK and internationally.
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- 1. One of the goals for Natura 2000, a key European Community programme of nature conservation, is to produce a network of protected areas. An analysis of the Natura 2000 marine sites proposed in the most recently agreed list for the Atlantic region (northern Portugal to Denmark, n=298) was used to characterize the network in terms of site areas and inter‐site distances. Sites were considered as part of the network when they included any of the marine Natura 2000 Annex I habitat types found in the Atlantic region (excluding lagoons).
- 2. The median size of individual sites was 7.6 km2 with a median separation among neighbouring sites of 21 km (range 2–138 km).
- 3. A connectivity analysis was used to identify the potential reliance of species on areas of habitat outside the proposed network. This analysis was based on the assumptions that: (a) species with low dispersal capacity will persist in sites when local reproductive effort sustains the resident population and (b) greater dispersal scale will link sites in the network, but implies a greater loss of recruits from the local population. For intermediate dispersal scales (2–20 km), at least half of the proposed sites are likely to be both too small and too isolated to support populations in the network. The conservation of intermediate dispersers in such sites may therefore be more dependent on habitat outside the network than is the case for other dispersal capabilities. Species with both dispersal scales above 20 km and low habitat specificity may have a metapopulation structure with exchange of dispersing individuals occurring among protected sites. Species with increasing degrees of habitat specificity will need dispersal scales greater than 20 km to avoid dependence on areas outside the proposed network.
- 4. Most sections of the Atlantic region coastline contain proposed Nature 2000 sites. An analysis of site area and average isolation at the 1° latitude by 1° longitude scale indicated that relatively well designated sections (in terms of area and site spacing) of the coast were interspersed with less well designated sections. Analyses of overall habitat availability and population genetic studies are required to assess the significance of varying levels of protection at this scale.
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