Disturbance to a foraging seabird by sea-based tourism: Implications for reserve management in marine protected areas

The provision of recreational opportunities is one of the important human goals of marine protected areas. However, as levels of recreational use increase, human disturbance is likely to cause significant detrimental effects upon wildlife. Here we evaluate the best managing options to mitigate the impact of sea-based tourism on the foraging activity of an endangered population of European shags, Phalacrocorax aristotelis, in a coastal marine protected area (Cíes islands, north-western Iberia). Boat disturbance elicited a characteristic avoidance behavior that resulted in a substantial reduction in foraging activity as levels of boat use increased. Moreover, boats excluded shags from the best feeding areas, resulting in higher densities of foragers in areas of little boat traffic. We used a behavioral model to explore the effects of managing strategies aimed at reducing the impact of boats on the foraging activity of shags. Our model suggested that in low boat disturbance scenarios limiting the number of boats using the reserve would be a better management option than habitat protection (i.e. the establishment of set-aside areas free of boat traffic). On the contrary, when boat disturbance levels are high the protection of habitat is recommendable, even if spatial variation in habitat quality is unknown or poorly assessed. Our study stresses the point that management strategies to minimize disturbance to foraging seabirds may depend on the spatial overlap between sea-based recreational activities and foraging seabirds and the spatial variation in marine habitat quality for seabirds.     

Does whale watching in Southern New England impact humpback whale (Megaptera novaeangliae) calf production or calf survival?

There is growing concern about the effects of wildlife tourism on biologically important parameters in target species and/or populations. We tested whether whale watch vessel exposure affected either the calving rates or calf survival to age 2 in humpback whales (Megaptera novaeangliae) on their feeding grounds off of southern New England, where individually identified whales have been studied intensively for decades and whale watch pressure is intense. Whale watch exposure did not correlate with either the calving rate (# of calves/# of years sighted) or calf production and survival of individual females, although a breakpoint analysis showed a slight negative trend up to 1649 min (or 20 boat interactions). In some comparisons, whales with more exposure were significantly more likely to produce calves and to have those calves survive. Logistic regressions including exposure and prey variables also failed to show negative effects of exposure in predicting calf productivity or survival. A limited comparison of calves seen only in an alternate habitat without whale watching showed similar return rates to those in the exposed area. Our data include limited suggestions that some animals (i.e., females alive when whale watching started) might be more susceptible to impacts than others. However, we found no direct evidence for negative effects of whale watch exposure, and suggest that short-term disturbance may not necessarily be indicative of more meaningful detrimental effects on either individuals or populations.     

Possible cryptic stock structure for minke whales in the North Atlantic: Implications for conservation and management

The minke whale is the last of the great whale species to be hunted in significant numbers. Effective management must include an understanding of how genetic diversity is divided and distributed among putative local populations, and as for many migratory species, this is complicated for the minke whale by large-scale seasonal movement among geographic regions. The problem is that the geographic identity of breeding populations is not known, and instead these whales are predictably found and hunted where different breeding stocks may mix on seasonal feeding grounds. Here we use microsatellite DNA and mtDNA markers to investigate minke whale population structure across the species’ range in the North Atlantic. We found no evidence of geographic structure comparing putative populations in recognized management areas, though some limited structure had been indicated in earlier studies. However, using individual genotypes and likelihood assignment methods, we identified two putative cryptic stocks distributed across the North Atlantic in similar proportions in different regions. Some differences in the proportional representation of these populations may explain some of the apparent differentiation between regions detected previously. The implication would be that minke whales range extensively across the North Atlantic seasonally, but segregate to some extent on at least two breeding grounds. This means that established stock boundaries in the North Atlantic, currently used for management, should be re-considered to ensure the effective conservation of genetic diversity.     

The role of social aggregations and protected areas in killer whale conservation: The mixed blessing of critical habitat

Protected areas are often proposed as tools for conserving endangered populations of marine megafauna. Our study area includes a voluntary no-entry reserve embedded within wider critical habitat for Threatened ‘northern resident’ killer whales under Canada’s Species at Risk Act. Our study quantified the reserve’s importance to whales by assessing habitat preference in a behavioural context, and population-level implications of that preference given threats from human activities, such as oil spills resulting from shipping traffic. We recorded summertime activities of whales from 1995 to 2002. Whales were observed on 397 of 530 (74.9%) days. Whales showed strong preference for the reserve over adjacent waters, and used it preferentially for feeding and beach-rubbing. While the area comprises ∼0.001% of the whales’ range, an overall average of 6.5% of the population was present each day. Frequently, >50% of this small population was aggregated in the restricted and heavily trafficked waterway of Johnstone Strait. Using the Potential Biological Removal equation, we calculated potential annual mortality limits (ML) of 2.2 animals. Mean group size in the area exceeded ML on 55.8% of days overall, and 98.8% of days when conditioning on whale presence. The whales’ high reliance on a trivial fraction of their range means that opportunities are routine for one stochastic, catastrophic event to cause population decline. On 20 August 2007, a barge loaded with ∼10,000 L of diesel sank in the area, exposing 25% of the population. This underscores the importance of identifying critical habitat for threatened populations, and ensuring meaningful protection.     

An assessment of the behaviors of overwintering manatees as influenced by interactions with tourists at two sites in central Florida

We used a combination of focal animal and scan samples over the course of two winter seasons to assess behavioral patterns of manatees as a function of the presence and activities of recreational swimmers and boats in and around Crystal River National Wildlife Refuge, Florida. The nature and outcome of human-manatee interactions and the frequency of harassment of manatees by swimmers (as defined by the US Fish and Wildlife Service) were also recorded. The use of protected (no-entry) sanctuaries by manatees was significantly greater when both the numbers of swimmers and boats increased, and when water temperatures were lower in surrounding areas. The time manatees spent bottom-resting and nursing decreased while the time spent milling and swimming increased when swimmers were present compared with when they were absent. Over half of the direct interactions recorded between swimmers and manatees constituted some form of harassment as defined by Refuge guidelines, and manatees were far more likely to terminate these interactions than were swimmers. We conclude that the existence of no-entry sanctuaries is very important for the conservation of manatees in the area and thought must be given to expanding the sanctuary network. Furthermore, additional efforts at enforcement and public education are needed. We address, qualitatively, several potential management options to better-secure manatees at this critical time of the year.     

Evaluating potential infectious disease threats for southern resident killer whales, Orcinus orca: a model for endangered species

Infectious diseases have the potential to play a role in the decline of threatened wildlife populations, as well as negatively affect their long-term viability, but determining which infectious agents present risks can be difficult. The southern resident killer whale, Orcinus orca, population is endangered and little is known about infectious diseases in this species. Using available reference literature, we identified 15 infectious agents (bacteria, viruses, and fungi) reported in free-ranging and captive killer whales, as well as 28 additional infectious agents reported in free-ranging and captive odontocete species sympatric to southern resident killer whales. Infectious agents were scored as having a high, medium, or low ability to affect fecundity or reproductive success, to cause disease in individual animals, and to cause epizootics. Marine Brucella spp., cetacean poxvirus, cetacean morbilliviruses, and herpesviruses were identified as high priority pathogens that warrant further study. Using identified pathogens to develop a standardized necropsy and disease testing protocol for southern resident killer whales and sympatric odontocetes will improve future efforts to better understand the impacts of priority and non-priority infectious agents on southern resident killer whales. This model can be used to evaluate potential infectious disease risks in other threatened wildlife populations.     

Ecosystem consideration in conservation planning: energy demand of foraging bottlenose whales (Hyperoodon ampullatus) in a marine protected area

The Gully, a submarine canyon off eastern Canada, was nominated as a pilot Marine Protected Area (MPA) in 1998, largely to safeguard the vulnerable population of northern bottlenose whales (Hyperoodon ampullatus) found there. The boundaries and ultimate management regime for the MPA for this area remain under review. We have estimated the energy consumption of bottlenose whales in the Gully based on the number of whales present at any time, their trophic level, the food requirements of each whale, and the rates of energy transfer between trophic levels. These calculations suggest that there must be a substantial spatial subsidy in the underlying foodweb of the submarine canyon to support the bottlenose whales using the Gully. A substantial area beyond the distribution of bottlenose whales in the area will therefore require protection. Conservation priorities to protect such subsidies will primarily involve additional protection at the level of the sea floor. Spatial subsidies are probably common in the marine environment, urging careful ecological analysis in the establishment of marine reserves and suggesting that conservation priorities need to take into account key ecological linkages and processes that are vital for sustaining species and habitats of concern.     

Management costs for small protected areas and economies of scale in habitat conservation

Protected area management must be resourced adequately to achieve its conservation objectives. The variability in management costs across candidate sites for protection therefore should inform conservation planning. For example, when considering whether to accept a donation of a property, a conservation organisation must determine whether an adequate endowment is available to fund future management activities. We examine variation in management costs across 78 small protected areas in the UK that are managed by a conservation NGO, the Yorkshire Wildlife Trust. Management costs exceed acquisition costs when funded on an endowment basis and are not correlated with acquisition costs or with proxy measures for conservation costs commonly relied upon in conservation planning studies. A combination of geographic, ecological and socioeconomic characteristics of sites explains 50% of the variation in management costs. Site area is the most important determinant of management costs, which demonstrate economies of scale; implementing conservation management on an additional hectare adjacent to a larger protected area would incur a lower cost than doing the same adjacent to a smaller site. In evidencing this effect of site area, we avoid problems of spurious correlation that confound previous studies. Protected areas that encompass a greater richness of priority habitats for conservation also require more expensive management. Conservation organisations may have little option but to create small protected areas to conserve biodiversity in highly fragmented landscapes, but the decision to do so should take account of the greater cost burden that small protected areas incur.     

Roost availability may constrain shorebird distribution: Exploring the energetic costs of roosting and disturbance around a tropical bay

High tides force shorebirds from their intertidal feeding areas to refuges known as roosts. This paper explores the energetic costs of roost disturbance of great knot (Calidris tenuirostris) and red knot (C. canutus) at Roebuck Bay, North-western Australia, assessing disturbance levels at different roost sites through direct observation and automatic radio-telemetry, and applying physiological equations and predictive roost choice models to estimate energetic costs of disturbance through a complete tidal cycle. The study area had a variety of roosts, but use of each was constrained by conditions of tide and time. The roost most suitable for shorebirds on daytime high tides of intermediate height experienced high levels of disturbance from both natural sources (birds of prey) and humans. Flight costs caused by disturbance at this site exceeded the costs of flying to and roosting at the nearest alternative roost, 25 km away. However, shorebirds did not roost at the alternate site, possibly because of the risk of heat stress in a prolonged flight in tropical conditions. Increases in disturbance levels at just one of the roost sites of Roebuck Bay would increase energetic costs substantially, and could easily reach the point at which feeding areas accessed from this roost cannot be used without incurring a net energy deficit. Roost availability can therefore limit access to feeding areas and hence limit population size. Adequate provision and management of roost sites is accordingly an important consideration in conservation of sites used by coastal shorebirds.     

Shortcuts for marine conservation planning: The effectiveness of socioeconomic data surrogates

Marine protected area (MPA) networks designed without consideration of the interests of local communities are likely to fail. However, in many regions where conservation action is needed most urgently, socioeconomic data are not available at spatial scales relevant to conservation planning. In the Philippines, the primary stakeholders relevant to conservation efforts in coastal waters are small-scale fishers. Unlike commercial fisheries, no logbook data are kept to record fishers’ spatial effort and usage patterns. We investigated the effects of including different surrogates for small-scale fishing effort in the systematic design of an MPA network for Siquijor Province. We compared a reserve selection scenario in which socioeconomic data were not considered with four different surrogates for fishing effort and with empirical data on the spatial distribution of fishing effort collected through interviews. We assumed that minimising opportunity costs to fishers would increase the likelihood that they would support and comply with MPA implementation, resulting in more effective conservation. Surrogates modelled on the number of fishers or boats in each community consistently outperformed those based on population census data. However, none of the surrogates we tested were able to accurately predict fine-scale resource use patterns. Whilst socioeconomic surrogates may be able to assist conservation planners to identify regional-scale opportunities where conservation objectives may be met more easily, they cannot act as a shortcut for comprehensive consultation with communities, which will be required to identify actual sites for MPA implementation.     

虾夷扇贝浮筏养殖作业改造与试验

该文针对目前虾夷扇贝(Patinopecten yessoensis)浮筏养殖作业用工量大、劳动强度高、工作效率低、耗能高以及尾气和噪音污染严重等问题,通过对獐子岛虾夷扇贝浮筏养殖作业工作模式与回收养殖吊笼方式的调研,提出了虾夷扇贝浮筏养殖作业的改进方案,并通过海上生产对比试验,得出以下结论:第1阶段以8 m长浮筏养殖作业船为母船,安装了电动拔梗装置、拔笼装置、抖笼装置、筛苗装置以及齿形滑轮滑梗装置,改变单纯依靠人力工作的作业模式为机械化作业模式,不仅用工人数及劳动强度大幅降低,并且拔笼量较原浮筏养殖作业平均每天单船提高了56.01%,耗能费用降低了13.95%;第2阶段在保留第1阶段机械化设备的基础上,对养殖作业船只的作业模式进行了改造,用船长12 m、船宽3.3 m、型深0.7 m,尾挂机型号洋马/CY1115,最大功率16.2 kW的作业船代替了原来船长8 m、船宽2.4 m、型深0.5 m,尾挂机型号ZS195,最大功率9.7kW的作业船,并省去了辅助运输船舶,将养殖作业和辅助运输合并为一条船。试验结果显示,拔笼数量较第1阶段改造的浮筏养殖作业模式平均每天单船提高了31.69%,较原浮筏养殖作业模式平均每天单船拔笼量提高了1.05倍。第2阶段改造的浮筏养殖作业船的装载和运输能力满足实际工作需求,平均每天单船耗能费用与第1阶段改造的浮筏养殖作业模式无显著性差异,较原浮筏养殖作业模式降低了14.12%。同时第2阶段改造的浮筏养殖作业模式较原浮筏养殖作业模式其单船年节省费用1.08万元。由此说明改造后的浮筏养殖作业装备及作业方式具有节能、高效等特点,推广应用前景广阔。     

Dolphin-watching tour boats change bottlenose dolphin (Tursiops truncatus) behaviour

Over the last decade there has been considerable growth in marine mammal-watching tourism throughout the world. Due to the species use of coastal habitats, bottlenose dolphins are most frequently exposed to dolphin-watching tourism. We conducted boat-based focal follows of schools of bottlenose dolphins to determine the effect of boats on dolphin behaviour. A CATMOD analysis showed that behaviour differed by boat number, in particular, resting behaviour decreased as boat number increased. Dolphins rested less and engaged in more milling behaviour in the presence of permitted dolphin-watching boats compared to non-permitted boats. An increase from 49 to 70 permitted trips per week and a change in their departure times resulted in a further decrease in resting behaviour. Currently the effects of boats, in particular permitted boats, on dolphin resting behaviour whilst they are in the Bay of Islands, are substantial. In the light of these findings we suggest that current legislation in New Zealand is not affording this isolated population protection from disturbance.     

Factors affecting abundance of bowhead whales Balaena mysticetus in the eastern arctic of North America, 1915–1980

The severely depleted bowhead whale Balaena mysticetus has failed to recover from overexploitation during the 18th and 19th centuries in the Eastern Arctic. Although commercial whaling for bowheads ended in this region about 1915, bowhead whaling by native people has continued until recently in parts of the Eastern Arctic. Low-level but persistent hunting by Inuit (Eskimos) may have inhibited bowhead population increase. Two natural mortality factors can be documented—ice entrapment and predation by killer whales Orcinus orca. There is little direct evidence of ice-related mortality but a strong circumstantial argument that ice conditions affect survival. Killer whales are known to prey on most species of large whales, and we believe bowhead whales and right whales Eubalaena glacialis are especially vulnerable. The bowhead's apparent failure to recover in the Eastern Arctic may be due to a combination of continued low-level hunting, habitat instability, and predation. Complete protection from all forms of hunting is necessary to ensure the bowhead's survival. Environmental disturbances due to industrial development in the Arctic may have direct and indirect impact on bowhead habitat and behaviour, creating an urgent need for further study.     

Measuring the cost of risk avoidance in brown bears: Further evidence of positive impacts of ecotourism

The objective of this study was to determine the cost to female brown bears with cubs of avoiding risk, or perceived risk, from both large adult male bears and ecotourists. We measured salmon consumption by brown bears in British Columbia under different risk scenarios (the presence and absence of large male bears and people). Declines occurred despite superabundant food where consumption was never limited by salmon abundance.While there were significant changes in the proportion of time spent foraging and in the consumption of captured fish between periods with and without ecotourists present, there was no change in foraging effectiveness, catch per unit effort.Selection of sub-optimal habitats to reduce predation risk incurs energy costs. Risk avoidance reduced daily salmon consumption by females with cubs by more than one third. By associating with people, females with cubs were able to avoid encounters with large, potentially aggressive males, which avoided people in both time and space. Controlled human activity at feeding sites can provide a temporal feeding refuge for vulnerable age/sex classes. This is the first study to quantify the energetic cost of intra-specific risk-avoidance for a large carnivore.     

Statistical modeling of North Atlantic right whale migration along the mid-Atlantic region of the eastern seaboard of the United States

North Atlantic right whale feeding and calving behaviors provide predictable spatial and temporal windows in which to conduct surveys and facilitate collection of opportunistic sightings data. Migration behavior makes it more difficult to locate and sample marine animals systematically or to observe them opportunistically. The lack of data creates a critical gap in understanding social behavior; it also hampers the development of mitigation strategies to anthropogenic disturbances such as vessel strikes, acoustic pollution and entanglements. We employ regression analysis to fill this gap to model northerly movements of North Atlantic right whales in the coastal mid-Atlantic migratory corridor of the United States. The modeling suggests an early to mid-March departure from Jacksonville, Florida, with a 30 day departure range; an average travel time of 21-24 days to the tip of Long Island, corresponding to a mean migration/displacement rate of 1.5-1.7 knots (2.8-3.1 km/h). Right whales migrating with calves begin their northern migration several days after right whales migrating without calves. These statistical models can supplement the absence of migratory survey data and help direct and stratify survey efforts in migratory corridors. The combination of rigorous statistical prediction with direct observation also should facilitate the creation of more effective mitigation measures. The methods employed here can be applied to other megafauna elsewhere around the world in many situations where migratory data are sparse.     

Perceived risk, displacement and refuging in brown bears: positive impacts of ecotourism?

Ecotourism is a rapidly growing industry with unknown impacts on viewed wildlife that may require novel management action. We examined the impact of viewing activities on the behaviour of brown bears (Ursus arctos) in coastal British Columbia.Domination of the best feeding sites and human avoidance by large male bears has consistently been reported. We, however, saw displacement in time rather than space - during the viewing day large males were less active than at other times, while females with cubs tended to be more active.In each year, females with cubs spent similarly high proportions of their time fishing when people were present. In years with large male activity, less time was spent fishing when people were absent. When freed from the potential threat of large male bears, females with cubs showed no measurable impact of controlled human activity.Human presence at a feeding site impacts the behaviour of brown bears, but not as expected. Temporal avoidance of human activity by large males was observed; indications that they departed upon satiation, before the arrival of morning tours, however, suggests that there was little energetic impact. By displacing large males, viewing activities created a temporal refuge, enhancing feeding opportunities for subordinate age/sex classes. With the strong positive relationships between mean female mass and litter size, this may in turn increase population productivity.     

Identification of whale species by thin-layer isoelectric focusing of sarcoplasmic proteins.

Thin-layer isoelectric focusing was applied to the identification of whale (Cetacea) species by using water-soluble sarcoplasmic proteins of skeletal muscles. Twenty-eight samples consisting of 4 species (10 samples) of baleen whales (Mysticeti) and 8 species (18 samples) of toothed whales (Odontoceti) were analyzed. Each sample (approximately 1 g) was electrophoresed with Ampholine PAGplate, pH 3.5-9.5. The electrophoretic profiles were species-specific on the 4 toothed whale species that did not have a marked intra-species difference, and all 4 baleen whale species. However, the profiles were not specific on the 4 other dolphin species, even though they were discriminable from the other 4 toothed whale species. Numerical values of pIs and relative peak heights were obtained by densitometric analysis of the isoelectro-focused protein bands. The bands were also species-specific for the 8 toothed whale species mentioned. The values may be applicable to species identification without the need for a standard sample, which may not be readily obtainable. Experiments on test samples of minke and sel whales showed that bloodletting with ice water made the densities of isoelectro-focused bands thinner, although species identification was still possible by using the inside part of muscles. Heat treatment at below 60 degrees C for 10 min caused little denaturation; at higher temperatures the protein bands were diminished in a temperature-dependent fashion. Therefore, the present isoelectric focusing analysis should be applicable to small samples of whale meat, excluding several species of dolphins.     

Management options to reduce boat disturbance on foraging black guillemots (Cepphus grylle) in the Bay of Fundy

Boat disturbance of foraging black guillemots (Cepphus grylle) was studied at a breeding colony in the Bay of Fundy, Canada. Using observations from a cliff top, flushing behaviour was examined in relation to boat characteristics, guillemot behaviour, and environment conditions. The distance guillemots foraged from shore and the size, speed, and approach distance of boats were important factors predicting flushing probability. Guillemots foraged further from shore at low tide presumably making them more vulnerable to disturbance then. Using these results to identify the conditions that would minimize disturbance, management recommendations on boat speed and set-back distance were developed. At this site, a set-back distance of 600 m from shore with a speed limit of 25 km/h would reduce guillemot flushing probability to 10% most of the time. Although specific management options are proposed for this particular colony, the analytical approach used to identify an appropriate set back distance and some of the specific results are relevant to other locations and colonial waterbird species.     

Cost-effective abundance estimation of rare animals: Testing performance of small-boat surveys for killer whales in British Columbia

Top predators are often rare, subject to anthropogenic mortality, and possess life-history traits that make them inherently vulnerable to extinction. IUCN criteria recognise populations as Critically Endangered when abundance is <250 mature individuals, but estimating abundance of rare species can be more challenging than for common ones. Cost-effective methods are needed to provide robust abundance estimates. In marine environments, small boats are more widely accessible than large ships for researchers conducting sightings surveys with limited funds, but studies are needed into efficacy of small-boat surveys. This study compares line transect and mark-recapture estimates from small-boat surveys in summer 2004 and 2005 for ‘northern resident’ killer whales in British Columbia to true population size, known from censuses conducted by Fisheries and Oceans Canada. The line transect estimate of 195 animals (95% CI 27-559) used model averaging to incorporate uncertainty in the detection function, while the mark-recapture estimate of 239 animals (CI 154-370) used a simple two-sample Chapman estimator. Both methods produced estimates close to the true population size, which numbered 219 animals in 2004 and 235 in 2006, but both suffered from the small sample sizes and violations of some model assumptions that will vex most pilot studies of rare species. Initial abundance estimates from relatively low-cost surveys can be thought of as hypotheses to be tested as new data are collected. For species of conservation concern, any cost-effective attempt to estimate absolute abundance will assist status assessments, as long as estimates are presented with appropriate caveats.     

Cost-efficient conservation for the white-banded tanager (Neothraupis fasciata) in the Cerrado, central Brazil

Population viability analyses are widely used to support decisions for the management of single species, but there are few studies that explicitly take into account realistic economic costs. In this study we determine the most cost-efficient conservation management options for the white-banded tanager (Neothraupis fasciata) in the protected areas of the Cerrado in central Brazil. We use the PVA model VORTEX to simulate the ability of different management options to improve population persistence and then assess the effectiveness of each option given a fixed budget. We discover that the best strategy for improving the viability of white-banded tanager populations is to use fire management and nest protection to increase fecundity. In small reserves and a low budget then fire management alone is the best strategy, but if the budget is larger fire management with nest protection as a mixed strategy is better. In large reserves the best strategy is to do nest protection and with large budgets there is a negligible difference between spending all the money on nest protection versus a mixed strategy. If we had not included financial considerations in our analysis of management options then we would have discarded fire management as an option, even though it can be the best strategy.