Fishers' knowledge detects ecological decay in the Mediterranean Sea.
Ontology highlight
ABSTRACT:
SUBMITTER: Veneroni B
PROVIDER: S-EPMC8068750 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We investigate long-term changes in the Mediterranean marine resources driving the trawl fisheries by analysing fishers' perceptions (Traditional Ecological Knowledge, TEK) throughout the Mediterranean Sea during the last 80 years. To this end, we conducted an extended set of interviews with experienced fishers that enabled us to classify species (or taxa) as 'decreasing' or 'increasing' both in terms of abundance, as well as average size in the catch. The aspect that most clearly emerged in all the investigated areas over time was the notable increase of fishing capacity indicators, such as engine power and fishing depth range. Atlantic mackerel, poor cod, scorpionfishes, striped seabream, and John Dory demonstrated a decreasing trend in the fishers' perceived abundance, while Mediterranean parrotfish, common pandora, cuttlefish, blue and red shrimp, and mullets gave indications of an increasing temporal trend. Although, as a rule, trawler captains did not report any cataclysmic changes (e.g. extinctions), when they were invited to estimate total catches, a clear decreasing pattern emerged; this being a notable finding taking into account the steep escalation of fishing efficiency during the past century. The overall deteriorating status of stocks in most Mediterranean regions calls for responsible management and design of rebuilding plans. This should include historical information accounting for past exploitation patterns that could help defining a baseline of fish abundance prior to heavy industrial fisheries exploitation.
| S-EPMC4364015 | biostudies-literature
Project description:BackgroundEcosystem modeling applied to fisheries remains hampered by a lack of local information. Fishers' knowledge could fill this gap, improving participation in and the management of fisheries.MethodologyThe same fishing area was modeled using two approaches: based on fishers' knowledge and based on scientific information. For the former, the data was collected by interviews through the Delphi methodology, and for the latter, the data was gathered from the literature. Agreement between the attributes generated by the fishers' knowledge model and scientific model is discussed and explored, aiming to improve data availability, the ecosystem model, and fisheries management.Principal findingsThe ecosystem attributes produced from the fishers' knowledge model were consistent with the ecosystem attributes produced by the scientific model, and elaborated using only the scientific data from literature.Conclusions/significanceThis study provides evidence that fishers' knowledge may suitably complement scientific data, and may improve the modeling tools for the research and management of fisheries.
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Project description:Climate changes and anthropogenic pressures are causing a biodiversity decline in terms of species number and genetic diversity, reducing the adaptability and evolvability of natural communities. Transitional water ecosystems are more sensitive to habitat reduction and degradation and, thus, are more exposed to biodiversity declines requiring biodiversity monitoring programs for their conservation. Environmental DNA (eDNA) metabarcoding represents a high-throughput tool for biodiversity assessment that is facilitating data collection for biodiversity monitoring. In this study, we applied, for the first time, eDNA metabarcoding in a Mediterranean coastal lagoon to assess the ecological features of eukaryotic phytoplankton communities. We sampled water in seven different lagoon sites and amplified the extracted DNA with primers targeting the variable region 4 (V4) of the 18S rRNA gene marker. The results demonstrated the validity of eDNA studies to provide insights into lagoon phytoplankton composition, establish the structure and spatial variation of phytoplankton communities, and evaluate its correlation to abiotic factors. Finally, the genetic distances analysis suggests that the different spatial distribution of OTUs, at least for the Tetraselmis genus, reflects the genetic background.
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Project description:BackgroundAlthough fishers' knowledge has been recently considered into management programmes, there is still the need to establish a better understanding of fishers' perceptions and cognition. Fishers can provide novel information on the biology and ecology of species, which can potentially be used in the management of fisheries. The knowledge fishers have and how they classify nature is empirically based. It is common, for example, to observe that fishers' taxonomy is often represented by the generic level, one of the hierarchical categories of folk classification that is somewhat analogous to the Linnean genus, as it groups organisms of a higher rank than the folk species.In this study we compiled the knowledge fishers have on local fish, such as their folk names, diet and habitat.MethodsFive coastal communities widely distributed along the Brazilian coast were studied: two from the northeast (Porto Sauípe and Itacimirim, in Bahia State, n of interviewees?=?34), two from the southeast (Itaipu at Niterói and Copacabana at Rio de Janeiro, Rio de Janeiro State, n?=?35) and one from the south coast (Pântano do Sul, in Santa Catarina State, n?=?23). Fish pictures were randomly ordered and the same order was presented to all interviewees (n?=?92), when they were then asked about the species name and classification and its habitat and diet preferences.ResultsFishers make clusters of fish species, usually hierarchically; fishers of the coast of Brazil use mostly primary lexemes (generic names) to name fish; and fishers did not differentiate between scientific species, since the same folk generic name included two different scientific species. Fishers provide information on species to which there is scarce or no information on diet and habitat, such as Rhinobatos percellens (chola guitarfish, arraia viola or cação viola), Sphoeroides dorsalis (marbled puffer, baiacu), Mycteroperca acutirostris (comb grouper, badejo) and Dasyatis guttata (longnose stingray, arraia, arraia manteiga).Conclusionsfishers' knowledge on fish diet and fish habitat can be strategic to management, since their knowledge concentrates on the fishery target species, which are the ones under higher fishing pressure. Besides, fishers showed to have knowledge on species still poorly known to science.
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Project description:The Maldives tuna fishery landings in 2018 were 148, 000 t and accounted for nearly a quarter of the global pole-and-line tuna catch. This fishery partially relies on a network of 55 anchored fish aggregating devices (AFADs) deployed around the archipelago. About one-third of the total pole-and-line tuna catch is harvested at AFADs. Although the AFAD fishery has existed for 35 years, knowledge on the behaviour of tuna in the AFAD array is still limited, precluding the development of science-based fishery management. In this study, local ecological knowledge (LEK) of fishers was used to improve our understanding of tuna behaviour, through personal interviews of 54 pole-and-line fishers from different parts of the archipelago. Interview results suggest that during the northeast monsoon tuna are more abundant on the eastern side of the Maldives, while during the southwest monsoon they are more abundant on the western side of the Maldives. Most fishers believed that tuna tend to stay at the AFADs for 3 to 6 days and remain within 2 miles from the AFADs when they are associated. Fishers believe that strong currents is the main factor for tuna departure from AFADs, though high sea surface temperatures and stormy conditions were also thought to contribute to departures. Moderate currents are believed to be a favourable condition to form aggregations at the AFADs while other factors such as suitable temperature, prey and attractants enhance this aggregation. Fishers also believe that there are multiple schools segregated according to size and species at AFADs and that catchability is higher at dawn and in the late afternoon when the tuna occur shallower in the water column. This study is an important step towards engaging the Maldivian tuna fishers into a science-based fishery management.
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Project description:Local ecological knowledge (LEK) has been found to be one of the main bridges to manage biocultural diversity. We analyzed the factors affecting LEK maintenance and transmission in a Mediterranean watershed. We used a mixed methods approach to evaluate the agricultural LEK in three different dimensions: biological, soil and water management, and forecasting. We found that the main factors for its maintenance were the respondent's time living in the area and the social relationships established among farmers, which involved partner collaboration and farmer information exchanges. Protected areas also played a key role for maintaining the LEK associated with soil and water management. Finally, we found that outmigration and mechanization were the most important indirect drivers of change underlying LEK erosion. We suggest that environmental policies should focus on promoting this experiential knowledge, considering both intergenerational renewal and the gendered aspects of this knowledge.
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Project description:Fishers worldwide operate in an environment of uncertainty and constant change. Their ability to manage risk associated with such uncertainty and subsequently adapt to change is largely a function of individual circumstances, including their access to different fisheries. However, explicit attention to the heterogeneity of fishers' connections to fisheries at the level of the individual has been largely ignored. We illustrate the ubiquitous nature of these connections by constructing a typology of commercial fishers in the state of Maine based on the different fisheries that fishers rely on to sustain their livelihoods and find that there are over 600 combinations. We evaluate the adaptive potential of each strategy, using a set of attributes identified by fisheries experts in the state, and find that only 12% of fishers can be classified as being well positioned to adapt in the face of changing socioeconomic and ecological conditions. Sensitivity to the uneven and heterogeneous capacity of fishers to manage risk and adapt to change is critical to devising effective management strategies that broadly support fishers. This will require greater attention to the social-ecological connectivity of fishers across different jurisdictions.
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