Variability in Isotope Discrimination Factors in Coral Reef Fishes: Implications for Diet and Food Web Reconstruction

Interpretation of stable isotope ratios of carbon and nitrogen (δ13C and δ15N) is generally based on the assumption that with each trophic level there is a constant enrichment in the heavier isotope, leading to diet-tissue discrimination factors of 3.4‰ for 15N (ΔN) and ∼0.5‰ for 13C (ΔC). Diet-tissue discrimination factors determined from paired tissue and gut samples taken from 152 individuals from 26 fish species at Ningaloo Reef, Western Australia demonstrate a large amount of variability around constant values. While caution is necessary in using gut contents to represent diet due to the potential for high temporal variability, there were significant effects of trophic position and season that may also lead to variability in ΔN under natural conditions. Nitrogen enrichment increased significantly at higher trophic levels (higher tissue δ15N), with significantly higher ΔN in carnivorous species. Changes in diet led to significant changes in ΔN, but not tissue δ15N, between seasons for several species: Acanthurus triostegus, Chromis viridis, Parupeneus signatus and Pomacentrus moluccensis. These results confirm that the use of meta-analysis averages for ΔN is likely to be inappropriate for accurately determining diets and trophic relationships using tissue stable isotope ratios. Where feasible, discrimination factors should be directly quantified for each species and trophic link in question, acknowledging the potential for significant variation away from meta-analysis averages and, perhaps, controlled laboratory diets and conditions

Socio-economic drivers of specialist anglers targeting the non-native European catfish (Silurus glanis) in the UK.

Information about the socioeconomic drivers of Silurus glanis anglers in the UK were collected using questionnaires from a cross section of mixed cyprinid fisheries to elucidate human dimensions in angling and non-native fisheries management. Respondents were predominantly male (95%), 30-40 years of age with £500 per annum. The proportion of time spent angling for S. glanis was significantly related to angler motivations; fish size, challenge in catch, tranquil natural surroundings, escape from daily stress and to be alone were considered important drivers of increased time spent angling. Overall, poor awareness of: the risks and adverse ecological impacts associated with introduced S. glanis, non-native fisheries legislation, problems in use of unlimited ground bait and high fish stocking rates in angling lakes were evident, possibly related to inadequate training and information provided by angling organisations to anglers, as many stated that they were insufficiently informed

Why Should We Preserve Fishless High Mountain Lakes?

High mountain lakes are originally fishless, although many have had introductions of non-native fish species, predominantly trout, and recently also minnows introduced by fishermen that use them as live bait. The extent of these introductions is general and substantial often involving many lakes over mountain ranges. Predation on native fauna by introduced fish involves profound ecological changes since fish occupy a higher trophic level that was previously inexistent. Fish predation produces a drastic reduction or elimination of autochthonous animal groups, such as amphibians and large macroinvertebrates in the littoral, and crustaceans in the plankton. These strong effects raise concerns for the conservation of high mountain lakes. In terms of individual species, those adapted to live in larger lakes have suffered a higher decrease in the size of their metapopulation. This ecological problem is discussed from a European perspective providing examples from two study areas: the Pyrenees and the Western Italian Alps. Species-specific studies are urgently needed to evaluate the conservation status of the more impacted species, together with conservation measures at continental and regional scales, through regulation, and at local scale, through restoration actions, aimed to stop further invasive species expansions and to restore the present situation. At different high mountain areas of the world, there have been restoration projects aiming to return lakes to their native fish-free status. In these areas autochthonous species that disappeared with the introduction of fish are progressively recovering their initial distribution when nearby fish-free lakes and ponds are available

The endemic Comoros Islands fruit bat Rousettus obliviosus: ecology, conservation, and Red List status

Rousettus obliviosus is a megachiropteran bat endemic to the Comoros Islands in the western Indian Ocean. The species is broadly distributed on Grande Comore, Mohéli, and Anjouan, but appears to be absent from Mayotte. Roost sites were found to be both shallow and deep caves, in dark locations with infrequent human disturbance. Colony size ranged from 100 to several thousand and at two sites seasonal variation was observed. Total estimated population size was 7,100–17,100. R. obliviosus fed on a variety of native and non-native tree fruits and flowers, and was found in native forest habitats, underplanted forest and agricultural areas. R. obliviosus is a manoeuvrable flyer able to hover for brief periods and may echolocate. A small range, sensitivity to disturbance, limited roost site availability and deforestation combine to threaten this species. We suggest that the current IUCN Red List status of Lower Risk: near threatened should be revised to Vulnerable. Protection of roost sites, further surveys to identify additional roosts, further ecological research, and protection of remaining forest are conservation priorities for R. obliviosus.published_or_final_versio

Engaging recreational fishers in management and conservation: global case studies.

Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management measures such as stocking and introduction of non-native fishes. Nevertheless, recreational fishers can be instrumental in successful fisheries conservation through active involvement in, or initiation of, conservation projects to reduce both direct and external stressors contributing to fishery declines. Understanding fishers' concerns for sustained access to the resource and developing methods for their meaningful participation can have positive impacts on conservation efforts. We examined a suite of case studies that demonstrate successful involvement of recreational fishers in conservation and management activities that span developed and developing countries, temperate and tropical regions, marine and freshwater systems, and open- and closed-access fisheries. To illustrate potential benefits and challenges of involving recreational fishers in fisheries management and conservation, we examined the socioeconomic and ecological contexts of each case study. We devised a conceptual framework for the engagement of recreational fishers that targets particular types of involvement (enforcement, advocacy, conservation, management design [type and location], research, and monitoring) on the basis of degree of stakeholder stewardship, scale of the fishery, and source of impacts (internal or external). These activities can be enhanced by incorporating local knowledge and traditions, taking advantage of leadership and regional networks, and creating collaborations among various stakeholder groups, scientists, and agencies to maximize the probability of recreational fisher involvement and project success

Regional Planning for Linking Parks and Landscape: Innovative Issues

Since 2000, the emerging international indications (new paradigms relating to the protected areas, the European Landscape Convention, the socio-ecological approach of resilience) have expanded the relationship between protected areas and landscape. The paper reflects on conceptual innovations with reference to the methodological approach of some countries: the assessment of the landscape in the United Kingdom as a tool for defining policies and plans capable of integrating and harmonizing the development of human societies with the conservation of ecological and landscape stability and the territorial enhancement policies in the Netherlands that promote territorial development starting from nature and the landscap

Organized recreational fishing in school, knowledge about nature and influence on outdoor recreation habits

In this study we have investigated the effectiveness of a one day school-basedintervention with recreational fishing (in Swedish called Klassdraget) in increasingenvironmental awareness, interest in nature and recreational fishing in pupils agedbetween 8 and 12. Our results suggest a weak positive association between exposure tonatural environments in a recreational fishing context and interest in nature andrecreational fishing. We found the intervention to have no effect on the frequency offishing, interest in fishing more, or number of visits in nature during spare time.Knowledge about nature and possibly also environmental awareness are positivelyaffected and these effects can be traced as long as three years after the intervention. Ourfindings also reveal a low correlation between frequency of nature visits and selfreportedinterest in nature. The observed effects of Klassdraget are small but appear tobe larger for girls, who are traditionally less interested in recreational fishing whencompared with boys