Use Of Local Ecological Knowledge Research Articles

Use of Local Ecological Knowledge on the Natural Recruitment of Bivalve Species of Commercial Exploitation in a Natura Area

The current study provides valuable insight into the ecological risks and decline of the bivalve fishery and biodiversity in the Amvrakikos Gulf over the last 50 years through a triangulation of information from in situ surveys and expert judgment, supplemented with historical archives. In situ sampling showed that bivalve species composition was a typical composition of benthic fauna consisting of the olive green cockle, Cerastoderma glaucum, the grooved carpet shell, Ruditapes decussatus, and the Mediterranean mussel, Mytilus galloprovincialis. Interviews confirmed the dramatic decrease in the abundance of striped venus clam, Chamelea gallina, and noble pen shell Pinna nobilis, both of which might be attributed to human-induced impacts, habitat degradation and climate change. Official data depicted a gradual reduction of bivalve catches since 1980 and massive degradation of the resources after 2000. As a result, the bivalve fishery was abandoned, having a negative impact on the local socio-economic community. The present study fills in a gap in knowledge for preserving species biodiversity that is critical to the health of the coastal environments.

Local fishers experience can contribute to a better knowledge of marine resources in the Western Mediterranean Sea

In this study we explore fishers’ perceptions in the Ebro Delta area, Western Mediterranean, throughout structured questionnaires. Specifically, we compare the coherence of information provided by fishers with those resulting by scientific studies in terms of the status of demersal marine resources in the Ebro Delta area; we describe temporal trends of demersal key species in the area with fishers’ perceptions; and we explore the use of Local Ecological Knowledge (LEK) as an alternative data sources to reduce the gap of knowledge on the spatial distribution and temporal trends of sensitive and vulnerable benthic marine species. Our results document important changes in the bottom trawling activity in the study area and in the abundance of commercial species with time according to fishers’ perceptions. Our results mostly match quantitative information from national statistics and stock assessment analyses. In addition, we document important changes in the presence of Vulnerable Marine Ecosystems (VMEs) in the study area due to the by-catch of habitat forming species with time. According to fishers’ perceptions, habitat forming species occur in the area, but were more frequently captured incidentally in the 1980 s and 1990 s. Overall, our study evidences that fisher’s perception represents an important source of complementary information to describe bottom trawling fisheries characteristics and the long-term changes of demersal target species in the Western Mediterranean Sea. Moreover, it highlights that LEK can provide fundamental and additional information on ecosystem changes and it can be a useful tool to increase the knowledge on spatial distribution and on temporal trends of vulnerable benthic species.

Who is the expert? Evaluating local ecological knowledge for assessing wildlife presence in the Peruvian Amazon

AbstractAmazonian wildlife population studies often employ conventional biological survey methods to assess species presence but a growing number of studies are making use of local ecological knowledge (LEK) household surveys. Despite concerns in the scientific community over the accuracy and precision of LEK, scant research to date compares data from conventional biological survey methods with data gathered from household surveys. An important question among scientists is who should be approached when collecting household survey data for wildlife inventories, both for accurate data and for ethical concerns. In this article, we report on the accuracy and precision of LEK household surveys for wildlife inventories based on data collected along the Napo River in Peru using 10 land transect surveys, 5 river transect surveys, 487 camera trap days, and 37 LEK household surveys. Our findings indicate that the household surveys for wildlife inventories are accurate in comparison to biological survey methods, and that they may outperform conventional surveys for certain aquatic, ephemeral, and cryptic terrestrial species. We find no statistical differences among households defined by participation in hunting, community leadership, or primary livelihood strategy. Community members recommend that scientists first solicit wildlife data from community leaders and then hunters. Through the use of retrospection, LEK surveys can reveal how wildlife presence changes through time in remote, data‐poor tropical forests. Use of LEK household surveys is recommended as a useful complement to other methods, with attention to collecting data ethically in collaboration with local communities.

Scaling up local ecological knowledge to prioritise areas for protection: Determining Philippine pangolin distribution, status and threats

Local ecological knowledge (LEK) can provide cost-effective baseline ecological data across large geographical areas, and is increasingly seen as an important source of information for rare and cryptic species. However, to date, its use as a practical tool for prioritising conservation action is limited. Pangolins are the world’s most heavily trafficked wild mammals and all species are in decline. The Philippine pangolin (Manis culionensis) is Critically Endangered but conservation efforts are hindered by a lack of knowledge on where populations still exist and where in situ action should be prioritised. We conducted the first range-wide systematic survey for the species using household interviews (n = 1296) to provide new data on pangolin distribution, status and threats, and to assess the use of LEK for highlighting priority areas for conservation. LEK about pangolins was high (87% of respondents recognised pangolins and provided further information), with evidence of pangolin occurrence in 17 of the 18 municipalities surveyed. The majority (70%) of respondents had seen a pangolin, but most (72%) perceived pangolins to be ‘rare’ or ‘very rare’, and local use of pangolins was reported across the species’ range. Spatial differences in sighting frequencies, perceived abundance and reported population trends were observed, providing an important baseline to identify priority sites for targeted research and community-based pangolin conservation.

Use of Local Ecological Knowledge to Detect Declines in Mammal Abundance in Kogyae Strict Nature Reserve, Ghana.

The scarcity of environmental data means that other sources of information are needed to complement empirical evidence for conservation decisions. We, therefore, aimed to explore Local Ecological Knowledge (LEK) on mammal abundance and qualitative population trends through interviews from 331 local people in and around Kogyae Strict Nature Reserve, Ghana. The results show that 62% of the respondents perceived that mammal abundances had decreased, 31% perceived stability, and 8% perceived that mammals had increased between 2006 and 2017. The respondents attributed the decline to habitat degradation and illegal hunting. The knowledge of local people about mammal population trends is consistent with reported mammal encounters by law enforcement rangers. However, the length of residence, location of communities, and cardinal direction of communities influenced local peoples' knowledge of mammal abundance and population trends. Our results highlight the ability of LEK to provide reliable ecological information on animal abundance and qualitative population trends. Integrating LEK into monitoring and management is appealing because it can be cost-effective, enhance community participation, and provide novel insights into sustainable resource use.

Climate change resilience: lessons from local climate-smart agricultural practices in Ghana

The need to adapt to the changing climate is one of the important concerns of our time. However, the use of local ecological knowledge (LEK), which farmers have built up over the years to adopt climate-smart agriculture (CSA) practices, has been less explored by researchers and policy scientists. Leveraging on LEK, this study explores various local CSA practices, their benefits and management constraints and suggests ways to improve local CSA practices to enhance farmers’ resilience to climate change (CC). We conducted eight focus group discussions (FGD) in eight farming communities in the Western region of Ghana. The data from the FGD was complemented by secondary data from sources such as peer-reviewed journal articles, organisational websites, and quarterly reports. The study found that farmers used LEK to identify key local CSA practices, including agroforestry, cover cropping, crop rotation, mulching, and mixed cropping. However, some of their farming practices are not consistent with sustainable agricultural practices. Key issues that need immediate attention include (i) limited access to agricultural inputs prevented farmers from adopting CSA, (ii) land tenure issues adversely affected access to arable land for farming, (iii) inadequate agricultural training for farmers on CSA practices, (iv) limited access to agricultural information on CSA options, and (v) high labour-intensive activities for some CSA practices. We maintain that governmental efforts to improve local CSA, and in the context of increasing resilience of farmers and local communities, need to engage relevant stakeholders and communities to formulate and develop an effective climate-smart agricultural action plan. The policy implications of these findings and recommendations for future research are also discussed and documented.

Evaluating the use of local ecological knowledge (LEK) in determining habitat preference and occurrence of multiple large carnivores

Understanding habitat preferences and distribution of threatened species is a cornerstone of conservation, however many of the techniques available can be resource intensive. One cost-effective method is by collecting information on species presence and absence from people who regularly interact with the area of interest, also known as Local Ecological Knowledge (LEK). However, the reliability of this type of data has been questioned, especially when there is a possibility that the focal species is being misidentified or their presence misreported. This can introduce false negatives, when a species is present but has not been reported, and false positives, when the species has been reported but is not present. These biases are not always accounted for which can result in the under- or overestimation of species presence. To better understand the reliability of LEK data, we compared the outputs of five different analytical techniques to that of a more widely accepted approach, resource selection functions (RSF), using GPS-collar data from three different carnivore species (African lion Panthera leo, cheetah Acinonyx jubatus and African wild dog Lycaon pictus). Hierarchical models which accounted for the possibilities of both false negatives and false positives most closely matched that of the RSFs, especially for the two rarer species; African wild dog and cheetah. Our results show that when both false negatives and false positives are accounted for that LEK can be used as a rapid and cost-efficient tool for assessing threatened species which can be adopted into practical conservation projects.

Examining the Consistency of Folk Identifications of Trees to Implement Community-Based Biodiversity Monitoring

Several factors may compromise plant identifications provided by local informants, affecting the basis for incorporating local ecological knowledge (LEK) in scientific biodiversity assessments. Our study analyzes how site, informants’ background, and tree characteristics affect the consistency of folk identifications and the apparent correspondence between folk and Linnaean taxonomies. Twenty-eight informants performed in situ identifications of randomly selected trees at two sites in Indonesia and Vietnam. At both sites, older informants and informants who actively used trees had higher probabilities of proposing names for the trees. Naming consistency was higher where informants had good access to and daily use of the forest. Trees with particular morphological and anatomical characteristics, useful species, and landmark trees were more likely to be consistently named. Correspondences between folk and Linnaean taxonomies were clearer in the site with higher folk naming consistency. Findings contribute empirical evidence to inform research design and use of LEK in forest monitoring.

Biology, ecology and behavior of the acoupa weakfish Cynoscion acoupa (Lacepède, 1801) according to the local knowledge of fishermen in the northern coast of Brazil

Local ecological knowledge (LEK) of fishers and other actors involved in the fishery can be provide information on the life cycle of fish species they harvest, help defining low-cost sampling projects, new biological hypotheses, management activities and policy measures. This study focuses on fishers’ LEK on diet, feeding, spawning grounds, reproductive size, exploited sizes and perceived changes in abundance over the years of the acoupa weakfish (Cynoscion acoupa), a commercially important marine species. Results from interviews with 240 actors (fishers, captains and boat owners) involved in C. acoupa fisheries in eight municipalities in the northern coast of Brazil indicated that: (a) C. acoupa feeds in areas with rocky bottoms down to the depth of 30 m, eating mainly fish, particularly another weakfish (Macrodon ancylodon) and sardines (Engraulidae); (b) this fish spawns in rocky and non-estuarine habitats; (c) the spawning period mentioned by fishers coincided with the harvest period, but was in disagreement with published scientific information; (d) the median minimum length of individuals of C. acoupa carrying eggs according to interviews was of 70 cm, which was smaller than the length reported in biological studies, possible due to the selectiveness of fishing; (e) there is an overall perception of a decrease in the abundance of C. acoupa among the interviewed fishers, which is compatible with studies on stock exploitation of this species. The current dearth of financial and human resources available for scientific research underlines the importance of making use of LEK to improve fishery policy and management.

Fishers’ Local Ecological Knowledge (LEK) on Connectivity and Seascape Management

In developing countries where data and resources are lacking, the practical relevance of Local Ecological Knowledge (LEK) to expand our understanding of the environment has been highlighted. The potential roles of the LEK varies from direct applications such as gathering environmental information to a more participative involvement of the community in the management of resources they depend on. Fishers’ LEK could therefore be useful in order to obtain information to advance management of coastal fisheries. Many targeted fish species migrate between habitats to feed, spawn or recruit, connecting important habitats within the seascape. LEK could help provide answers to questions related to this connectivity and the identification of fish habitat use and migrations for species and areas where such knowledge is scarce. Here we assess fishers’ LEK on connectivity between multiple habitats within a tropical seascape, investigate the differences in LEK among fisher groups and the coherence between LEK and conventional scientific knowledge (CSK). The study was conducted in Zanzibar, Tanzania, a tropical developing country, in 2017. One hundred and thirty-five semi-structured interviews were conducted in six different locations focusing on fish migrations, and matching photos of fish and habitats. Differences between fisher groups were found, where fishers travelling further, exposed to multiple habitats, and fish with multiple gears had a greater knowledge on connectivity patterns within the seascape than those that fish locally, in single habitats and with just one type of gear. A high degree of overlap in LEK and CSK was found, highlighting the potential benefits of collaboration between scientists and fishers and the use of LEK as complementary information in the management of small-scale fisheries.

Changes in local knowledge and its impacts on ecological resources management: The case of flyingfish culture of the Tao in Taiwan

The use of local ecological knowledge (LEK) has been advocated for coastal ecological and environmental resource management (EERM), noting that successful management on the resources has been implemented for centuries by many coastal societies based on their LEK. However, changes in LEK are observed in many instances worldwide and have caused impacts on the EERM. This study reports industry-, government- and culture-driven changes of a LEK and the impacts of the changes on the environment. Taking the Tao of Taiwan's Orchid Island as an example, the connotations and trend of their flyingfish culture are analyzed. Specifically, the five conditions for achieving effective EERM established by Dietz et al. (2003) are used as the theoretical basis to analyze the impact of LEK changes on environmental change. The findings indicated that this culture complies with the conditions proposed and proved that application of the flyingfish culture to the management of Orchid Island's marine and fishery resources has its theoretical basis and advantages. However, the flyingfish culture was found to be facing major changes which has violated the conditions for effective management of shared resources. Various external factors have contributed to the changes in the flyingfish culture. These include the impacts of inappropriate government policies, modern science and technology, education, and the market economy. Especially, inappropriate policies have reduced the integrity of the flyingfish cultural landscape, incentivized the use of motorized boats, commodified the flyingfish, and expanded the market for related products. Some suggestions for managing the changes to the culture are proposed.

Use of local ecological knowledge as phenology indicator in native food species in the semiarid region of Northeast Brazil

Phenological studies that aggregate local ecological knowledge on the expression of phenophases may be useful in the elaboration of management strategies of species that are important to a given local system. In this study, we seek to answer the following questions: 1) How do the different phenophases of two important native food species are expressed in the three phytophysiognomies of the Cerrado (Brazilian savannah) where they are collected? 2) How does rainfall influence the expression of the phenophases of these species on the evaluated phytophysiognomies? 3) Does the local ecological knowledge of the residents of the Araripe National Forest (hereafter FLONA) on the phenophases of native species of high importance correspond to what occurs in the three phytophysiognomies of the Cerrado? The phenological monitoring was executed monthly from January 2012 to December 2013. In order to retrieve the local knowledge about phenophases, key informants from three communities located around the FLONA were selected. Rainfall is a limiting factor for the expression of the reproductive phenophases of Caryocar coriaceum, differently from what occurs for the vegetative phases and for Hancornia speciosa. There were no significant differences between the local knowledge of communities that collect resources in the forest and most of the data collected in the phenological evaluation. In addition, there was no difference in the expression of the phenophases among the three phytophysiognomies, also corroborating with the local ecological knowledge. As for the community that collects in agroforestry yards, there were significant differences between knowledge and expression of phenophases. Thus, the use of local ecological knowledge of people who collect resources in the forest has proved to be reliable and may be promising mainly in rapid diagnoses of biodiversity.

Hiding in the dark: Local ecological knowledge about slow loris in Sarawak sheds light on relationships between human populations and wild animals.

Local ecological knowledge (LEK) increases understanding of certain species and the threats they face, especially little-studied taxa for which data on distribution and conservation are often lacking. We conducted 111 semi-structured interviews in Sarawak, Malaysia, to collect local knowledge about the behavior and distribution of the Philippine slow loris (Nycticebus menagensis) from two ethnic groups, the Iban and the Penan. Our study revealed that male Penan respondents, generally hunters, who frequently go into the forest were better at identifying animals from pictures. Overall, the Penan have a more detailed knowledge of slow loris behaviors, habitat, and distribution than the Iban. The two ethnic groups have different attitudes towards slow loris as the Penan hunt, eat, or keep them as pets while the Iban consider them sacred and signifiers of good luck. We advocate the use of LEK for providing complementary information to scientific methods in the study of cryptic animals.

The use of Local Ecological Knowledge as a complementary approach to understand the temporal and spatial patterns of fishery resources distribution

BackgroundAcquiring fast and accurate information on ecological patterns of fishery resources is a basic first step for their management. However, some countries may lack the technical and/or the financial means to undergo traditional scientific samplings to get such information; therefore affordable and reliable alternatives need to be sought.MethodsWe compared two different approaches to identify occurrence patterns and catch for three main fish species caught with bottom-set gillnets used by artisanal fishers from northeast Brazil: (1) scientific on-board record data of small-scale fleet (n = 72 trips), and (2) interviews with small-scale fishers on Local Ecological Knowledge (LEK) (n = 32 interviews). We correlated (Pearson correlations) the months cited by fishers (LEK) as belonging to the rainy or to the dry season with observed periods of higher and lower precipitation (SK). The presence of the three main fish species at different depths was compared between LEK and SK by Spearman correlations. Spearman correlations were also used to compare the depths of greatest abundance (with the highest Capture per Unit Effort - CPUE) of these species; the CPUEs were descendly ordered.ResultsBoth methods provided similar and complementary bathymetric patterns of species occurrence and catch. The largest catches occured in deeper areas, which also happened to be less intensively fished. The preference for fishing in shallower and less productive areas was mostly due to environmental factors, such as weaker currents and less drifting algae at such depths.ConclusionBoth on-board and interview methods were accurate and brought complementary information, even though fishers provided faster data when compared to scientific on-board observations. When time and funding are not limited, integrative approaches such as the one presented here are likely the best option to obtain information, otherwise fishers’ LEK could be a better choice for when a compromise between speed, reliability and cost needs to be reached.

Evaluating fishermen\u2019s conservation attitudes and local ecological knowledge of the European sardine (Sardina pilchardus), Peniche, Portugal

BackgroundEuropean sardines are an important fishing resource in the North Atlantic. Recognized for its great commercial and economic value in southern Europe, this resource currently has low stock indices. From this perspective, fishers’ local ecological knowledge (LEK) is appreciated as an auxiliary tool in the management of sardines in this region. Our goal is to evaluate the LEK and attitudes towards the conservation of Sardina pilchardus in the typical fishing village of Peniche, Portugal.MethodsFrom June to September 2016, we carried out 87 semi-structured interviews. The four main points of the interviews were interviewee profile, fishing structure, fishermen’s LEK and attitudes towards sardine conservation. The interviews were qualitatively and quantitatively analyzed using a 3-point Likert scale. An LEK index and an attitude index were generated. Comparison analyses and correlations were made between the indices and variables of the interviewee profile and the fishing structure.ResultsThe mean LEK index was 0.55 and was classified as moderate. The attitudes index in relation to conservation was 0.76 and was classified as positive. This index had a positive and significant correlation with the LEK index and a significant negative correlation with the fishermen’s age. When the LEK index was compared with the educational level, significant differences were observed only between class A and class C. The result showed that the differences in the attitudes index were statistically significant when the three educational classes were compared.ConclusionsThe fishermen of Peniche in Portugal present moderate informal knowledge about the biology and ecology of sardines. Attitudes towards conservation were predominantly positive. Fishermen with greater LEK, with a higher educational level and at a younger age presented more positive attitudes in relation to environmental conservation issues in the present case of the sardine population. The LEK is not necessarily related to the educational level of the fishermen. We suggest environmental education programs for the communities that depend on this resource. The use of LEK and fishermen’s perceptions can help in the management of the European sardine fishery in Portugal.

How many remnant gibbon populations are left on Hainan? Testing the use of local ecological knowledge to detect cryptic threatened primates.

For Critically Endangered "species of extreme rarity," there is an urgent need to clarify the potential survival of remnant populations. Such populations can be difficult to detect using standard field methods. Local ecological knowledge (LEK) represents an important alternative source of information, but anecdotal reports of rare or possibly extinct species can contain uncertainty and error. The Hainan gibbon (Nomascus hainanus), the world's rarest primate species, is confirmed to only survive as a tiny remnant population in Bawangling National Nature Reserve, China, but unverified gibbon sightings have been reported from other forest areas on Hainan. We conducted a large-scale community interview survey to gather new data on patterns of primate LEK from 709 respondents around seven reserves across Hainan, to investigate the possibility of gibbon survival outside Bawangling and assess whether LEK can provide useful information for conservation management of cryptic remnant populations. Comparative LEK data for gibbons and macaques are consistent with independent data on the relative status of these species across Hainan. Local awareness and experience of gibbons was low across Hainan, including at Bawangling, but we recorded recent anecdotal gibbon reports from most reserves. A follow-up field survey at Limushan Provincial Nature Reserve did not detect gibbons, however, and documented intensive wildlife exploitation within this reserve. All other surveyed landscapes showed some statistically lower levels of respondent awareness, experience, or sighting histories of gibbons compared to Bawangling, and are therefore considered biologically unlikely to support gibbons. Unverified LEK data can provide important insights into the possible status of cryptic remnant populations when assessed carefully and critically in relation to data from known populations.

Use of local ecological knowledge to investigate endangered baleen whale recovery in the Falkland Islands

Baleen whale populations have increased around the world after the end of commercial whaling in the 1980s. Anecdotes from local inhabitants of the Falkland Islands tell of an increase in whale sightings after an almost complete absence. However, no long-term monitoring exists to assess such recovery. With increasing maritime activities around the Islands, local managers need to understand the status and distribution of baleen whales to avoid impeding the potential recovery process. In the complete absence of scientific data, harvesting local ecological knowledge (LEK) from residents could provide means to assess whether whale numbers are increasing. We collected historical knowledge and mapped historical observations through structured interviews with 58 inhabitants and filtered observations for the highest reliability. We also collated existing historical catch and sighting data to compare species composition in inshore and offshore waters. A total of 3842 observations were compiled from the 1940s to 2015. This collation of information provided first-time evidence on the return of the whales in the Falkland Islands' waters. There was a clear increase in numbers of whales sighted, from no observations in the 1970s to 350 observations between 2010 and 2015 for similar effort, mostly of endangered sei whales (Balaenoptera borealis) and fin whales (Balaenoptera physalus). We mapped contemporary whale sighting hotspots to inform current marine spatial planning efforts. The use of LEK is highlighted here as a useful way to gain a better understanding of changes in the status of threatened species when no scientific monitoring has been conducted.

Local ecological knowledge concurs with fishing statistics: An example from the abalone fishery in Baja California, Mexico

The use of local ecological knowledge (LEK) to assess species status has been controversial among marine scientists. While some consider this to be one of the few historical tools available to understand the extent of change that has occurred in marine animal populations and ecosystems with a long-term historical perspective, others believe fishers tend to exaggerate catches and that their memories cannot be considered a reliable source of information to assess species at risk of extinction. This study compares long-term fishery data on catches with fishers' memories in the abalone (Haliotis spp) fishery from Baja California, Mexico. Results show that historical landings and fishers' memories strongly concur in the history of how this fishery has collapsed over the last 60 years. Pearson correlation analysis between both sets of data reports a value of 0.75, showing a high correlation (p <0.0001), adding evidence to the increasing literature on the importance of local ecological knowledge to understand species' trends in marine ecosystems. As with any other proxy of population abundance, fishers' ecological knowledge gives an imperfect but informed trend on the status of marine species that should not be discarded by our own bias that ecological data always produces accurate estimations.

Evaluating the use of local ecological knowledge to monitor hunted tropical-forest wildlife over large spatial scales

Parry, L., and C. A. Peres. 2015. Evaluating the use of local ecological knowledge to monitor hunted tropical-forest wildlife over large spatial scales. Ecology and Society 20(3): 15. https://doi.org/10.5751/ES-07601-200315

Cetacean occurrence, habitat preferences and potential for cetacean–fishery interactions in Iberian Atlantic waters: results from cooperative research involving local stakeholders

Abstract Iberian Atlantic waters are heavily exploited by Spanish and Portuguese fisheries. Overlaps between fishery target species and cetacean diet, and between fishing grounds and cetacean foraging areas, can lead to cetacean–fishery interactions including bycatch mortality of cetaceans. The present study assesses cetacean distribution, habitat preferences and hotspots for cetacean–fishery interactions by using a cooperative research approach with stakeholder participation (fishers, fisheries observers, fisheries authorities, scientists), as well as the combination of different opportunistic data sources (interviews, on‐board observations). The usefulness of each data type is evaluated. The implications of results for the monitoring and mitigation of cetacean–fishery interactions are discussed. Generalized linear models and GIS maps were used to relate cetacean occurrence patterns to environmental variables (geographic area, water depth, coastal morphology) and to fishing activities (fishing grounds, fisheries target species). Common and bottlenose dolphins were the most frequently sighted species, the former in waters &gt;50 m, frequently from purse seiners and trawlers, and the latter particularly inside the south Galician rías and close to vessels operating further offshore in Portuguese waters. Harbour porpoises were seen over the whole continental shelf, often next to beach seines, while long‐finned pilot whales and striped dolphins were mostly seen from vessels fishing offshore. Results suggest that cetacean occurrence is linked to prey distribution and that interactions with fisheries are most likely for common dolphins (with coastal purse seines and offshore trawls), bottlenose dolphins and harbour porpoises (coastal nets). The different data sources were complementary and provided results broadly consistent with previous studies on cetacean occurrence in the same area, although sightings frequency for some cetacean species was biased by survey method. Opportunistic sampling has certain restrictions concerning reliability, but can cover a wide area at comparatively low cost and make use of local ecological knowledge to yield information required for cetacean conservation. Copyright © 2014 John Wiley &amp; Sons, Ltd.