Mediterranean Small-scale Fishery Research Articles

Efficient and sustainable: innovative pot design for a Mediterranean small-scale fishery

Efficient and sustainable: innovative pot design for a Mediterranean small-scale fishery

A threatened heritage: Sustainable alternatives for Mediterranean small-scale fisheries

This study underscores the crucial role of small-scale fisheries (SSF) in promoting sustainable fishing practices within the Mediterranean context, emphasizing the necessity to align fisheries commerce with local seafood consumption. SSF in the Mediterranean, particularly in the Balearic Islands, are vital for local communities, contributing significantly to fish catches, while being deeply intertwined with cultural heritage and traditional values. However, these fisheries face several threats, including resource depletion, management strategies favouring fleet reduction, and increase of seafood imports. Our research investigates the relationships between the local fishing sector and resident population, exploring perspectives on sustainability. We examine SSF activities and perceptions through face-to-face questionnaires in nine fishing ports and assess seafood consumption habits through phone questionnaires. The study reveals an aging fishing sector rooted in family traditions that face administrative hurdles in implementing strategies such as fish tourism and direct sales, but seeks to enhance local product consumption. Despite the traditional relevance of fish in the Mediterranean diet, our findings also show low consumption of fresh and local seafood due to consumer’s limited knowledge on local species and related cooking methods and perceived high costs. However, the cultural importance of these products remains undiminished. To reinforce the cultural heritage of SSF and improve the future perspectives of the sector, we advocated for a multi-pronged approach, including raising consumers’ awareness about local species, controlling local prices, and promoting certified products through a reduction in the administrative burden and by promoting the active involvement of SSF.

Mitigating bycatch in Mediterranean trammel net fisheries using species-specific gear modifications.

Small-scale fisheries (SSF) use static gear which are thought to interact with marine ecosystems more benignly than towed gear. Despite this, trammel nets, one of the most extensively used type of fishing gear in the Mediterranean SSF, generate large amounts of discards, which can account for 25% or more of the captured biomass. Discarded organisms may include endangered or threatened species such as elasmobranchs, as well as non-commercial invertebrates that damage fishing gear or cause disentanglement delays. We evaluated various trammel-net gear modifications, including (i) the use of a guarding net attached to the footrope, (ii) increasing the length of the rigging twine between the footrope and the netting panel, and (iii) decreasing the mesh size of the outer panels. The last two modifications were successful in lowering captures of the marbled electric ray Torpedo marmorata, which is commonly discarded in the study area. Both sorts of modifications are relatively simple, their manufacturing does not represent an added cost to implement, and most importantly they do not negatively affect the catch of the target species. The current study shows that prior evaluation of the discard profile of distinct métiers is essential to accomplish species-specific gear modifications and underlines the importance of collaboration among scientists, fishers and gear manufacturers.

Combining indicator trends to evaluate a typical Mediterranean small-scale fishery: The case study of Corsica

Marine communities are often affected by intense fishing pressure, and the related impacts can be detected and understood through bioindicators that assess stock biomass, the state of exploitation, species diversity, the average trophic level of catch, and changes in the catch mass. Here we apply a series of bioindicators to small-scale fishery catch data collected between 2011 and 2020 off Corsica in the north-western Mediterranean Sea. From these data, we (i) assess the state of the main stocks exploited around Corsica; (ii) study the evolution of the regional marine ecosystem and fisheries, (iii) compare the trends produced by these indicators and explore how these trends illustrate fishing pressure. During the 2011–2020 period, we observe: (i) a relatively constant mean length of catch; (ii) constant mean trophic level of the catch; (iii) a decreasing proportion of threatened species caught by the fishing gear; (iv) a general stability in catch per unit effort; and (v) stable discard proportions. We also note that the selected indicators occasionally produce significantly different trends, requiring a deeper analysis to comprehend what these divergences represent. The use of multiple indicators highlights the importance of a multimethod approach to obtain an accurate portrait of a marine ecosystem and the impacts of fishing on stocks. This study provides, for the first time, a summary of how exploited stocks off Corsica respond to pressure imposed by a typical Mediterranean artisanal fishery.

High bycatch rate of the coral Cladocora caespitosa offsets the low discards ratio in Thermaikos Gulf gillnet fishery

While hanging nets may have fewer overall environmental impacts than towed gears, they still catch unwanted species and sizes, which are then discarded. Gillnets are one of the most common types of nets used in Mediterranean small-scale fisheries, with commercial catches and discards containing a diverse range of fish and invertebrate species. In this study, the catch profile of gillnets in the Thermaikos Gulf (NE Mediterranean) was analyzed with a focus on the discarding of species with unfavorable conservation status, such as the Mediterranean-endemic scleractinian coral Cladocora caespitosa, which is listed as endangered due to declining population sizes. Our survey was conducted over two seasons (May to October in 2020 and 2021) and included 69 fishing trials under realistic fishing conditions. In general, gillnets exhibited a relatively low discards ratio (17.2%; 7.1% when only fish were considered) and a low prevalence and capture intensity of endangered or threatened species; during the entire survey, only one chondrichthyan was captured (1 specimen of Raja radula), while only two out of 54 fish species were of vulnerable IUCN status. These advantages were offset in part by the high catchability of C. caespitosa colonies, which occurred in 61% of hauls and accounted for 53% of total invertebrate biomass and 30% of total discarded biomass. The likelihood of hauling living colonies of C. caespitosa was higher when fishing over known coral beds (81% vs. 43%), and the overall probability of hauling C. caespitosa in any state was 18% higher over coral beds, suggesting that gillnets frequently detach colonies from the seafloor, which are then dispersed over a larger area as fragments with probably low survival potential. Our findings highlight the importance of identifying C. caespitosa beds so that fishermen avoid setting their nets in these areas, provided that they are well-informed and educated about the ecological significance of this endemic, threatened, and ecologically important species.

Multi‐specific small‐scale fisheries rely on few, locally essential, species: Evidence from a multi‐area study in the Mediterranean

AbstractAchieving sound management of small‐scale fisheries (SSFs) is globally recognized a key priority for sustaining livelihoods, local economies, social wealth and cultural heritage in coastal areas. The paucity of information on SSFs often prevents the proper assessment of different socio‐ecological aspects, potentially leading to draw inappropriate conclusions and hampering the development and adoption of effective policies to foster SSF sustainability. To respond to the growing global call to assess these fisheries, we carried out a multi‐disciplinary and data‐rich assessment of SSFs at 11 areas in 6 Mediterranean EU countries, combining the analysis of 1292 SSF fishing operations and 149 semi‐structured surveys of fishers. Specifically, we aimed at assessing (1) landed species contribution to SSF catches and revenues and (2) the spatial variability in a set of fishery socio‐ecological descriptors. Results highlighted that, in spite of a high species diversity, Mediterranean SSFs actually rely economically upon a very limited number of species with catch and revenues per unit of effort mostly determined by less than 5 species, that can guarantee high and stable catches and revenues over time. Moreover, some fishing communities were found to rely on a restricted number of gears. These evidences suggest, that some SSFs' properties often assumed, but never broadly verified, should be carefully reconsidered, especially when viewed from a broader socio‐ecological perspective, as in the case of the diversified portfolio or of the polyvalence of fishing gears. Taking the local scale into proper account is likely to reduce the risk of implementing management strategies potentially generating socio‐ecological inequalities.

Pots vs trammel nets: a catch comparison study in a Mediterranean small-scale fishery.

Passive bottom-set nets are the most widely used fishing gears in Mediterranean small-scale fisheries (SSFs). Trammel nets, in particular, have key advantages such as their ease of use and handling and high capture efficiency for numerous commercial species. However, they entail high discard rates (5–44% of the total catch) connected to high mortality, thus exerting an adverse impact on benthic communities, besides catching individuals of commercial species under the minimum conservation reference size (MCRS) and specimens of protected species. Fish pots are seen as alternative and a more sustainable gear type that allow reducing discards in SSFs. In this study, a collapsible pot was tested at three coastal sites in the north-western Adriatic Sea (GFCM GSA 17) to compare its catch efficiency with that of the local traditional trammel nets. Data analysis demonstrated a similar catch efficiency for the commercial species, both among sites and as a whole. Moreover, the trammel net caught a larger amount of discards, both in terms of species number and of CPUEW. The catch comparison study involved the two most abundant landed species, common cuttlefish Sepia officinalis and annular sea bream Diplodus annularis. The pots were more effective for S. officinalis, whereas the trammel net was more effective for the shorter length classes for D. annularis, which were mostly under the MCRS (12 cm). The innovative pots could provide a valuable alternative to the trammel nets traditionally used in the Adriatic Sea, at least in certain areas and periods. Their main advantages include that they do not require a different rigging and they can be used without bait, while their foldable design allows large numbers to be easily loaded on board SSF vessels. The results of this pilot study indicate that pots can achieve the objectives of reducing discards and bycatch in SSFs without penalizing the catch of commercial species.

Past and present of a Mediterranean small-scale fishery: the Greek sponge fishery—its resilience and sustainability

Global change impacts Mediterranean fisheries and the dependent human populations. Overfishing and epizootic diseases related to extreme climatic events are currently accepted as the main threats to the production of commercial bath sponges. Believing that other factors could have impacted this insular fishery, we assembled a 150-year-long series of sponge fishing data for Greece that was analyzed in relation with variations of the pressure and of the socio-economic contexts. Sponge fishing experienced huge variations, with notably two distant short periods when the production collapsed (late nineteenth century and between 1985 and 1991). Before the 1970s, these variations are mainly attributed to socio-economic and political changes. The monitoring of the catches per unit effort indicates a clear overfishing impact only after 1977. However, after the last collapse of the overall production which followed the severe disease outbreak of the late 1980s, the catch per unit effort showed a positive trend, which tends to indicate that the stocks available bear the present fishing pressure. Fishermen have adapted towards sustainable practices, by reducing their crew and also diversifying their targets, which nevertheless calls to a more accurate monitoring of such a small-scale fishery.

Shifting baselines in a Mediterranean small-scale fishery

The overexploitation of marine resources has led to a decrease in species abundance over time in many marine ecosystems worldwide. But as new fishers arise throughout the years, the perception of local abundance changes which might result in a “shifting baselines syndrome”. We investigated how the perception of fishers about species abundance changed through time (from 1970 to 2016) and space (five ports), through questionnaires in the small-scale/artisanal fisheries of Murcia, Spain. Two major results emerged, firstly species catches significantly decreased between the decades 1970–1990 and 2000–2016, possibly due to overfishing and habitat degradation. Catches of species with some particular functional traits decreased (96%) possibly due to lower plasticity or to a “fishing down the food web” effect. Secondly, some functional trait categories (very large size, deep water depth, large yearly displacements and very vagile) were the highest in the northern ports of San Pedro del Pinatar and Cartagena while Cabo de Palos had the highest values in species with solitary and territorial behaviour and vagile or sedentary mobility. Fishers’ perception of catch trends of commercial species seemed aligned with other sources of information for this area and might be key information in the absence of more quantitative information.

Net Fisheries’ Métiers in the Eastern Mediterranean: Insights for Small-Scale Fishery Management on Kalymnos Island

Small-scale fisheries constitute an important component of coastal human societies. The present study describes the small-scale net fisheries on Kalymnos Island (south-east Aegean Sea) that harbors the largest small-scale fleet in the eastern Mediterranean Sea. In addition, this study aims to evaluate their characteristics and economics. Relevant métiers were identified through a multivariate analysis by inputting the main resources and fishing gear data that were recorded during landings. Four main practices were observed being used as fishing gears, gillnets and trammel nets, targeting the species Mullus barbatus, Boops boops, Mullus surmuletus, Scorpaena porcus, and Sepia officinalis. Further analysis, which incorporated data concerning the type of the gear used, revealed 11 distinct métiers. Most of these métiers are practiced by other Mediterranean small-scale fisheries as well, in terms of target species, gear and seasonality. However, the métier that had its target species as B.boops is not practiced in other Mediterranean small-scale fisheries. The seasonal rotation of métiers was determined by the availability of different species rather than their market price. The results revealed the difference in fishing practice used by the fishermen in the study area compared to other fishing practices in the Mediterranean Sea. In particular, the fishermen of this study area targeted more species (B.boops) with a very low market price. They also provided essential information for the development and implementation of management plans aiming at the sustainability of small-scale fisheries.

Dolphin-Fisheries Interactions: An Increasing Problem for Mediterranean Small-Scale Fisheries

Dolphin-Fisheries Interactions: An Increasing Problem for Mediterranean Small-Scale Fisheries

Can ultraviolet illumination reduce sea turtle bycatch in Mediterranean set net fisheries?

Sea turtles suffer from the cumulative and synergistic effects of natural phenomena and human activities. Among the latter, incidental interaction with commercial fisheries is considered as the main threat to their conservation. Fixed nets are common gears traditionally used in Mediterranean small scale fisheries (SSF). The loggerhead turtle bycatch of fixed nets is estimated to be high and similar to that of trawl nets and longlines, but seems to be associated with higher mortality rates. Devices aiming at reducing sea turtle bycatch through gear modifications have largely been developed for large-scale commercial fisheries, i.e. longlines and trawls, but not for set nets. In the present study ultraviolet LED lamps, which have already proved to be effective visual deterrents along the Northern and Southern Pacific coasts, were mounted on fixed nets and assessed for their ability to reduce the loggerhead turtle bycatch in the Mediterranean set net fishery. No turtles were caught in the illuminated net, whereas 16 individuals were captured by the traditional net (mortality rate, 30%). There were no significant differences in the catch rates of target species. This is the first test of a BRD designed to reduce sea turtle bycatch in a Mediterranean set net fishery. A broad diffusion of these bycatch reducer devices (BRDs) would provide a significant contribution to the conservation of loggerhead turtles while enabling large-scale production and cost reduction. However, until this happens the cost of adopting this BRD cannot be afforded by the fishermen operating SSF.

Assessment and management of western Mediterranean small-scale fisheries

Nearly 75% of European fishing vessels belongs to small-scale fisheries (SSF). However, SSF have received little attention compared to industrial fisheries. In the Mediterranean Sea, where the SSF traditionally had a high socio-economic relevance, there is a widespread interest in securing its sustainable exploitation and viability. Here we analyze the SSF from Mallorca (Balearic Islands) using fishery statistics from the last 25 years (1990–2014). Although fleet size declined markedly (−55%), landings remained constant which might be related to different, not mutually exclusive explanations such as a decrease in unreported catches, stagnant and closed market or technological creeping. Multivariate analysis revealed eight different fishing tactics corresponding to the main target species. Aggregated, these eight species accounted for 52% and 71% of SSF landings weight and value, respectively. The fishery of these species is markedly seasonal and the landings of most of them showed important fluctuations but no clear trends. In contrast with the claims of SSF having lower impact on the natural resources than other fisheries, surplus production models revealed a generalized overexploitation of these target stocks, especially for the most high-valued species. Simulations with a bioeconomic model showed that fishing effort reductions of 38% would improve the health of fish stocks while increasing the economic profits to as much as 15% from current profits. If all stocks were kept below their MSY level, the reduction in fishing effort would have to be of 53% from current values. If the economic yield from the fishery was to be maximized (MEY), fishing effort would need to be reduced by 28%. Owing to important quantities of unreported catches in the most high-valued species, output values of the stock status indicators and the bioeconomic modelling should be taken with care beyond tracking trends in the fishery.

A network approach to by-catch in a multi-species Mediterranean small-scale fishery

Fisheries management has been traditionally focused on resource-based approaches that underscore the interaction between the sociological – e.g., fishermen behavior reflected in spatial allocation of fishing effort and gear choice – and the ecological component of the system. In this line, the network analysis offers valuable tools that allow the integration of both components, identifying emergent properties resulting from their interactions—e.g., management units. Specifically, modularity refers to the degree to which some individuals in a group or module have a higher probability of mutual connection than individuals in others groups. Compared to previous approaches in fisheries, modularity allows identifying discrete management units without subjectivity in the delimitation of groups (number and size). Herein, we represent the by-catch in the small-scale fishery (SSF) of Palamós (Catalonya, Spain) as a bipartite-network where nodes correspond to fishing events (152) and species (125), and links indicate the relationship among them. We identified nine modules composed by different combinations of catch composition, fishing areas, and fishing gears. Although they could resemble fishing tactics or mètiers, herein we suggest that modules as defined here could be considered management units not evident from other techniques. Finally, we stress the potential of modularity analysis in the definition of marine fish stocks and management units.

Application of a multi-annual generalized depletion model to the assessment of a data-limited coastal fishery in the western Mediterranean

A multi-annual generalized depletion model was applied to a coastal fishery in Vilanova i la Geltru (western Mediterranean) to assess the exploitation status of striped red mullet ( Mullus surmuletus ) and cuttlefish ( Sepia officinalis ), two of the main target species of Mediterranean small-scale fisheries. It is shown that in data-limited stocks, which is often the case in small-scale fisheries, catch and effort data at high temporal frequency (day, week, month) complemented with biological information and a priori knowledge (mean body weight, natural mortality and period of recruitment to the fishery) can be effectively exploited to produce assessment results applicable to fisheries management. For the two species analysed, the assessment results showed that exploitation rates are high and vulnerable biomass has been decreasing over the last 14 years.

The effect of monofilament thickness on the catches of gillnets for common sole in the Mediterranean small-scale fishery

Experimental fishing trials were carried out on an Italian commercial vessel to test gillnets of different monofilament diameters targeting common sole (Solea solea). The gillnets only differed in the nominal monofilament diameter: 0.18, 0.20, 0.22, 0.25, and 0.30mm. The nominal mesh size (stretched) was 72mm. A total of 47 taxa were caught. The mean number of species caught with 0.30mm monofilament was significantly lower than those obtained with the three thinnest diameters. Total number, number of commercial and discard of non-commercial species significantly decreased with the increase of monofilament diameter. The number of common sole and tub gurnard caught was not statistically different amongst diameters. No statistical differences were observed for the length–frequency distributions of common sole and tub gurnard caught with the different monofilament diameters. The analysis of the mechanism of capture for the common sole showed that for all diameters the main type of retention was snagging, and the percentage of individuals retained in such way decreased with the increase of diameters, while an opposite trend was observed for the common sole that were gilled. Monofilament thickness had a substantial effect upon the catch rates of the gillnets.

Small-scale fishery in the Balearic Islands (W Mediterranean): A socio-economic approach

Small-scale fisheries in Europe face an uncertain situation from different pressures that undermine its social and economic viability in the near future. We investigate the issue of sustainability and options for future development of small-scale fisheries by means of a case study in Majorca (Balearic Islands; W Mediterranean). We analysed the socio-economic status of this small-scale fishery by means of economic indicators derived from data obtained through questionnaires. Our results show that the economic profitability of this activity is low and that, under the current economic situation small-scale, fishing has limited attractiveness, a situation similar to other Mediterranean small-scale fisheries. However, as a producer of high-quality fresh fish fetching comparatively high prices, small-scale fishing should have a viable future if the factors identified as responsible for the low economic viability could be redressed (such as excessive fishing pressure on the resource because it is shared with other commercial or recreational fishers; inadequate pricing system). Reducing the conflicts with other users of the coastal zone, by appropriate spatial zonation (combined with the already existing network of MPAs), is a measure that receives a favourable opinion from professional fishers, while diversifying the activity by combining professional fishing with tourism-fishing is less attractive to professional fishers in the Majorca Island. This model of development is both acceptable to the stakeholders involved in the fishery and in line with current European policies (Marine Strategy Framework directive) which favour forms of spatial planning as fisheries management measures.

Fishing tactics dynamics of a Mediterranean small-scale coastal fishery

We analyzed the small-scale fishery in the port of Vilanova i la Geltrú (NW Mediterranean) to assess the fishing practices in this fishery and produce economic indicators of its status. We defined the fishing tactics (or métiers) of this fishery with a multivariate analysis approach for evaluating the main fishery resources and fishing gears employed. Our results show that netters in this fishery practice 7 types of fishing tactics. Five of these fishing tactics, in terms of target species, gear and seasonality, are also used in other small-scale Mediterranean fisheries. The main types of fishing gear (trammel nets, gillnets) and target species (Sepia officinalis, Solea vulgaris, Mullus surmuletus and Merluccius merluccius), and a well defined seasonality, are also observed in other studies of Mediterranean small-scale fisheries. We show that the seasonal rotation of fishing tactics is determined by the availability of different fish species rather than market price. Identifying the fishing tactics, which in the Mediterranean are relatively limited in number, of small-scale fisheries provides information for developing monitoring and management strategies for these fisheries. We also assessed the economic performance of the small-scale fishery in Vilanova i la Geltrú and its conflicts with other uses of the coastal zone. We conclude that small-scale fisheries are an economically viable activity although seriously threatened by concurrent uses of the coastal zone (conflict with other extractive activities; competition for space with tourism and leisure activities; pollution). The integrated management of the uses of the coastal zone is necessary in order to sustain small-scale fisheries, which have become less important in economic terms, but which are an important social component of local coastal communities and are a source of high quality seafood with a low ecological impact.

Assessment and bioeconomic analysis of the Majorca (NW Mediterranean) trammel net fishery

Trammel net is the main fishing gear used by artisanal fishers in Majorca Island (NW Mediterranean), and is representative of Mediterranean small-scale fisheries using static gear. The use of static gears close to the coast, where seasonal variability and spatial heterogeneity are high, promotes the diversification of fishing practices or metiers .W e analyze the seasonal dynamics of the nets used, target species (red and black scorpionfish, red mullet and cuttlefish) exploitation patterns and the socio-economic conditions under which this fishery takes place, based on General Fisheries Directorate daily sale records (2002-2006). Additional personal socioeconomic interviews allowed the characterization of the trammel net fishery, its fishing behaviour, cost structure and conflicts. Catch and effort data and market surveys are used to evaluate the level of exploitation of the target species and allowed describing Majorca trammel net fishery as an activity based on a sustainable resource. The main target species were found to be near their maximum sustainable yield both by means of a surplus production model (with parameters estimated by CEDA-Catch Effort Data Analysis, software) and an age structured assessment model based on yield-per-recruit analysis. Management actions currently debated by local administration and fishers focus on improving fishers' economic situation, rather than on protecting a threatened resource. One of the management actions proposed is a one day effort reduction, which was analyzed here with the help of a bioeconomic simulation model. A 15-year (2005-2020) simulation allows providing advice to local managers to focus on the commercialization aspects, in order to obtain a higher value to the fish production, rather than expecting to obtain higher profits only by a reduction of the offer.

Catch length analysis, relation to minimum landing sizes and management implications from a Mediterranean small-scale fishery (Patraikos Gulf, Greece)

Fisheries management in the Mediterranean is planned on the basis of fishing effort allocation, gear technical characteristics and minimum landing sizes (MLSs), the latter being a measure recently updated in the EU Mediterranean fisheries policy. Very few elements on the evaluation of the MLS in regard to the catch and landings of the small-scale fisheries in the Mediterranean exist and this is due to both the great heterogeneity of the sector and the lack of systematic monitoring. The catch length composition of five species ( Merluccius merluccius, Diplodus annularis, Mullus barbatus, Sepia officinalis and Squilla mantis) from a yearly record of small-scale fishing operations in the Patraikos Gulf (w. Greece, e. Mediterranean) was associated with temporal (season), spatial (depth of fishing, substrate type) and fishery (métier) characteristics by means of general linear models. Smaller individuals appeared in the catch in autumn for all five species indicating this season as suitable if a seasonal fishery closure was established. When length was found to be significantly different between different métiers this was either due to smaller mesh sizes ( M. barbatus) or due to gear type ( M. merluccius). For all species except S. officinalis, depth significantly affected length of individuals in the catch providing in the case of M. merluccius a clear association of bigger individuals with deeper fishing grounds. Substrate types also affected the length for the species D. annularis, M. barbatus. In relation to MLSs, the sizes of Mullus surmuletus and Scomber japonicus were fully legal, M. merluccius, M. barbatus, Solea vulgaris, Trachurus mediterraneus, Pagellus erythrinus had higher than 80% of the catch over MLS, while D. annularis, Diplodus sargus, Sparus aurata and Pagellus acarne had high fractions of the total catch below MLS. The métiers where undersized individuals appear were identified. Further management implications of the findings are discussed taking into account the current management scheme and the discarding practices in the area.