Global expansion of marine protected areas and the redistribution of fishing effort.

The expansion of marine protected areas (MPAs) is a core focus of global conservation efforts, with the "30x30" initiative to protect 30% of the ocean by 2030 serving as a prominent example of this trend. We consider a series of proposed MPA network expansions of various sizes, and we forecast the impact this increase in protection would have on global patterns of fishing effort. We do so by building a predictive machine learning model trained on a global dataset of satellite-based fishing vessel monitoring data, current MPA locations, and spatiotemporal environmental, geographic, political, and economic features. We then use this model to predict future fishing effort under various MPA expansion scenarios compared to a business-as-usual counterfactual scenario that includes no new MPAs. The difference between these scenarios represents the predicted change in fishing effort associated with MPA expansion. We find that regardless of the MPA network objectives or size, fishing effort would decrease inside the MPAs, though by much less than 100%. Moreover, we find that the reduction in fishing effort inside MPAs does not simply redistribute outside-rather, fishing effort outside MPAs would also decline. The overall magnitude of the predicted decrease in global fishing effort principally depends on where networks are placed in relation to existing fishing effort. MPA expansion will lead to a global redistribution of fishing effort that should be accounted for in network design, implementation, and impact evaluation.

Why coastal lagoons are so productive? Physical bases of fishing productivity in coastal lagoons.

Coastal lagoons are among the most productive marine ecosystems in the world. Annual primary production varies from 50 to > 500 g C m-2 year-1, being of the same order of magnitude as that of the upwelling areas. Many lagoons lie within the range of eutrophic (300-500 g C m-2 year-1) or hypereutrophic (> 500 g C m-2 year-1) conditions. The high productivity of coastal lagoons makes them subject of exploitation by many marine fishes and invertebrates, that use them as nursery areas and feeding grounds during their early life cycle phases, and most lagoons support important fisheries or maintain aquaculture exploitations. The high levels of their biological production can be explained by some of their common features as shallowness and the strong influence of terrestrial systems. Shallowness favors that the photic zone extends to the lagoon bottom and that wind can promote the resuspension of nutrients and organisms. The interaction with land also introduces significant amounts of nutrients. However, trophic variables can explain < 43 % of the fishing yields, and further than the trophic status of the lagoons, several works showed that the biological productivity of coastal lagoons can be explained by their geomorphological features such as the positive influence of shoreline development and the negative influence of depth. Using the Mar Menor lagoon as a case study, we propose that although nutrient inputs and light can be limiting factors for photosynthetic based productivity, increasing fishing yield up to a certain limit, the productivity of lagoons is mainly promoted by more general forces associated to physical and chemical gradients.

Prediction of fishing intensity and trends across South China Sea biogeographic zones.

The volume of industrial fishing in the South China Sea ranks among the top global sustainable fisheries concerns of the Food and Agriculture Organization (FAO). To better understand the scale of management challenges, biogeographic zones of the SCS were characterized, and within each a multivariate GAM (General Additive Model) was fitted to predict and map the complete fishing activities from 2017 to 2020. Model variables, some incomplete or with gaps, included: VIIRS DNB night-time light imagery; Global Fisheries Watch (GFW) data; satellite Ocean Colour; Sea Surface Temperature; and bathymetry data. Four biogeographic zones with differing fishing patterns and trends were identified. We used cross-validation and the GAM model's own tuning method for model prediction accuracy determination, which performed well in four biogeographic zones (R2 respectively: 0.62, 0.68, 0.74 and 0.71). High-intensity fishing grounds are mainly distributed in offshore continental shelf areas. From 2017 to 2019, high-intensity fishing grounds were located near the Beibu Gulf of Vietnam, south Vietnam, part of the Gulf of Thailand and the central Java Sea, where fishing effort greater than 50 h exceeded average annual SCS fishing intensity for several years. By season, intensity and extent of fishing in Spring were largest. In 2020, due to the impact of COVID-19, except for Spring, fishing volume generally decreased. Our experimental results provide new insights and an adaptable biogeographic modelling methodology to map the scale and intensity of regional fishing activities more accurately and completely. This more comprehensive database, that takes account of intrinsic biogeographic fishery context, will help improve and strengthen the regulation of fishing activities around the world.

High-resolution app data reveal sustained increases in recreational fishing effort in Europe during and after COVID-19 lockdowns.

It is well recognized that COVID-19 lockdowns impacted human interactions with natural ecosystems. One example is recreational fishing, which, in developed countries, involves approximately 10% of people. Fishing licence sales and observations at angling locations suggest that recreational fishing effort increased substantially during lockdowns. However, the extent and duration of this increase remain largely unknown. We used four years (2018-2021) of high-resolution data from a personal fish-finder device to explore the impact of COVID-19 lockdowns on angling effort in four European countries. We show that relative device use and angling effort increased 1.2-3.8-fold during March-May 2020 and generally remained elevated even at the end of 2021. Fishing during the first lockdown also became more frequent on weekdays. Statistical models explained 50-70% of the variation, suggesting that device use and angling effort were relatively consistent and predictable through space and time. Our study demonstrates that recreational fishing behaviour can change substantially and rapidly in response to societal shifts, with profound ecological, human well-being and economic implications. We also show the potential of angler devices and smartphone applications for high-resolution fishing effort analysis and encourage more extensive science and industry collaborations to take advantage of this information.

Fish eDNA detections in ports mirror fishing fleet activities and highlight the spread of non-indigenous species in the Mediterranean Sea.

Gathering comprehensive marine biodiversity data can be difficult, costly and time consuming, preventing adequate knowledge of diversity patterns in many areas worldwide. We propose fishing ports as "natural" sinks of biodiversity information collected by fishing vessels probing disparate habitats, depths, and environments. By combining rapid environmental DNA metabarcoding (eDNA) surveys and data from public registers and Automatic Identification Systems, we show significant positive relationships between fishing fleet activities (i.e. fishing effort and characteristics of the fishing grounds) and the taxonomic fish assemblage composition in eleven Mediterranean fishing ports. Overall, we identified 160 fish and 123 invertebrate OTUs, including at least seven non-indigenous species, in some instances well beyond their known distribution areas. Our findings suggest that eDNA assessments of fishing harbours' waters might offer a rapid way to monitor marine biodiversity in unknown or under-sampled areas, as well as to reconstruct fishing catches, often underreported in several regions.

Cambios históricos en el esfuerzo pesquero de la flota parguera de Taganga, Caribe Colombiano / Historical changes in the fishing effort of the parguera fleet of Taganga, Colombian Caribbean

RESUMEN La pesquería artesanal avanzada de lanchas "pargueras" que opera en el área norte del mar Caribe de Colombia ha experimentado grandes dificultades relacionadas con el volumen de los desembarcos, que han llevado al colapso económico de la flota. La disminución de la abundancia de los recursos ícticos ha ocasionado la expansión del área de pesca, el aumento en la duración del viaje de pesca, la disminución de los ingresos y el incremento de los gastos de operación. Existen vacíos en el conocimiento de la distribución espacial actual e histórica del esfuerzo pesquero de la flota, que no permiten asociarlos a los cambios en las abundancias, la composición de las capturas y la disminución de tamaños de las especies capturadas. Mediante entrevistas a pescadores y con la ayuda del conocimiento ecológico tradicional, el conocimiento local y el uso de sistemas de información geográfica, se mapeó la distribución espacial del esfuerzo pesquero y su comportamiento desde los años 70 hasta la actualidad. Como principal resultado, se evidenció un aumento promedio de 134,5km en la distancia del viaje de pesca en casi 50 años y cambios en el área y profundidades de pesca, que variaron desde los 27,8 a 1117,8km2 y de los 93,8 a 41,1m, respectivamente. Los resultados obtenidos constituyen insumos valiosos para la implementación de estrategias de manejo, orientadas a asegurar la sostenibilidad ecológica y la viabilidad económica de esta importante pesquería.

ABSTRACT The advanced artisanal fishery of fishing boats called "pargueras" that operates in the northern area of the Colombian Caribbean has experienced great difficulties related to the volume of landings that have led to the economic collapse of the fleet. The decrease in the abundance of fish resources has caused an expansion of the fishing area, increased duration of the fishing trip, decreased incomes and the increase in operating expenses. Existing knowledge gaps with respect to current and historical spatial distribution of the fleet's fishing effort prevent an association to changes in resource abundances, composition of catches and decreased species catch sizes. Through interviews with fishermen and based in traditional ecological knowledge, local knowledge and the use of geographic information systems, we mapped the spatial distribution of fishing effort and its inter-decadal behavior, from the 70s to present. The main result was a 134.5km increase in the distance of an average fishing trip in almost 50 years and changes in the surface area and fishing depths which varied from 27.8 to 1117.8km2 and 93.8 to 41.1m, respectively. The results obtained constitute valuable inputs for the implementation of management strategies aimed at ensuring the ecological sustainability and economic viability of this important fishery.

Environment outweighs the effects of fishing in regulating demersal community structure in an exploited marine ecosystem.

Global climate change has already caused bottom temperatures of coastal marine ecosystems to increase worldwide. These ecosystems face many pressures, of which fishing is one of the most important. While consequences of global warming on commercial species are studied extensively, the importance of the increase in bottom temperature and of variation in fishing effort is more rarely considered together in these exploited ecosystems. Using a 17 year time series from an international bottom trawl survey, we investigated covariations of an entire demersal ecosystem (101 taxa) with the environment in the Celtic Sea. Our results showed that over the past two decades, biotic communities in the Celtic Sea were likely controlled more by environmental variables than fisheries, probably due to its long history of exploitation. At the scale of the entire zone, relations between taxa and the environment remained stable over the years, but at a local scale, in the center of the Celtic Sea, dynamics were probably driven by interannual variation in temperature. Fishing was an important factor structuring species assemblages at the beginning of the time series (2000) but decreased in importance after 2009. This was most likely caused by a change in spatial distribution of fishing effort, following a change in targeted taxa from nephrops to deeper water anglerfish that did not covary with fishing effort. Increasing bottom temperatures could induce additional changes in the coming years, notably in the cold-water commercial species cod, hake, nephrops, and American plaice. We showed that analyzing covariation is an effective way to screen a large number of taxa and highlight those that may be most susceptible to future simultaneous increases in temperature and changes in exploitation pattern by fisheries. This information can be particularly relevant for ecosystem assessments.

Emergence of balanced harvesting in an agent-based model of an open-access small-scale fishery.

Fisheries management strategies in which large fish are selectively targeted and younger, smaller fish are protected can lead to disruption of stocks, truncation of the population size spectrum, and impaired recruitment. Balanced harvesting is an alternative approach, which distributes fishing mortality across a wide range of species and sizes in proportion to their natural productivity. Here, we investigate outcomes from an agent-based model of fishing, coupled with an ecological model for the dynamics of a single fish species in a small-scale fishery. In the model, individual fishing agents make decisions about whether to enter or exit the fishery, and what size fish to target, based on economic calculations about short-term profitability of alternative actions. Fishing mortality, aggregated across agents, affects the biomass and size structure of the stock, which in turn affects individual agents' yields, creating a feedback loop. We show that the autonomous fishing agents self-organise to produce a Nash equilibrium, in which yields are equalised across agents. The aggregate fishing mortality that emerges in this equilibrium state is closely aligned with the distribution of productivity across body size. We conclude that balanced harvesting is an emergent outcome of the model. This occurs despite the absence of any externally imposed regulations on total fishing effort, catch or target sizes. However, controls on overall harvesting pressure are required to avoid overfishing.

[Probability distribution characteristics of stock density in offshore of northern South China Sea.] / 南海北部近海渔业资源密度概率分布特征.

Based on catch data from the bottom trawl survey by eight cruises in offshore of northern South China Sea during 2014-2017, we analyzed the stock density distribution and explored its probability distribution with statistical method, which was further used to estimate the mean stock density in this region. The results showed that the coefficient of variation (CV) for stock density ranged from 0.67 to 1.03 for all the periods, indicating a highly uneven spatial distribution of stock density. The frequency distribution of fishery resource density was characterized by obvious right-skewed, which was dominated by stock density of 0-1000 kg·km-2. The results of one sample Kolmogorov-Smirnov test indicated that three probability distribution patterns were suitable for stock density in this region, including Lognormal, Gamma and Weibull distributions. In terms of the mean stock density estimation, the values from Lognormal showed no statistically significant difference from those from others, but the opposite result was obtained between Gamma and Weibull distributions. Compared with 1960s-1970s, the appropriate probability distribution pattern of stock density has changed from single to multiple types. Variation of the proportion of low catch resulted from the changes in the structure of fishery resources, fishing effort and climate change might cause the alte-ration of probability distribution.

Seascape models reveal places to focus coastal fisheries management.

To design effective marine reserves and support fisheries, more information on fishing patterns and impacts for targeted species is needed, as well as better understanding of their key habitats. However, fishing impacts vary geographically and are difficult to disentangle from other factors that influence targeted fish distributions. We developed a set of fishing effort and habitat layers at high resolution and employed machine learning techniques to create regional-scale seascape models and predictive maps of biomass and body length of targeted reef fishes for the main Hawaiian Islands. Spatial patterns of fishing effort were shown to be highly variable and seascape models indicated a low threshold beyond which targeted fish assemblages were severely impacted. Topographic complexity, exposure, depth, and wave power were identified as key habitat variables that influenced targeted fish distributions and defined productive habitats for reef fisheries. High targeted reef fish biomass and body length were found in areas not easily accessed by humans, while model predictions when fishing effort was set to zero showed these high values to be more widely dispersed among suitable habitats. By comparing current targeted fish distributions with those predicted when fishing effort was removed, areas with high recovery potential on each island were revealed, with average biomass recovery of 517% and mean body length increases of 59% on Oahu, the most heavily fished island. Spatial protection of these areas would aid recovery of nearshore coral reef fisheries.

Jatuarana fishing dynamics Brycon amazonicus (Spix & Agassiz, 1829)of the upper and middle Madeira River Basin / Dinâmica da pesca da Jatuarana Brycon amazonicus (Spix &Agassiz, 1829) do alto e médio rio Madeira

The jatuarana (Brycon amazonicus), is an important species for the Madeira River commercialfisheries. The paper aims to characterize the jatuarana fishing dynamics in the middle Madeira River andtest whether there are differences dowstreams and upstreams the Teotônio waterfall. Commercial fisherieslandings were monitored daily at 15 ports or riverine communities along that stretch, using semistructuredinterviews with fishermen. With data from the fishing monitoring program of UHEs SantoAntônio and Jirau we analysed: the yield, catch per unit effort (CPUE), length structure, locations andfishing gear used, between 2009 to 2011.The fishing yield of this species was temporaly analyzed with datafrom the Fishermen Colony of Porto Velho city (Rondônia state, Brazil), between 1990 to 2012. The yieldand the CPUE showed significant differences by area and locations and the capture of the species wascarried out primarily in the channel river and banks river through gillnets. In addition, the samplescollected in the upstream area have higher distribution and modal lengths than from those collecteddownstream. These results suggest that the areas require distinct management measures.

A jatuarana (Brycon amazonicus) é uma espécie importante para a pesca comercial do médio rioMadeira. O objetivo deste trabalho foi caracterizar a dinâmica da pesca da jatuarana na região e testardiferenças entre os trechos a jusante e montante da Cachoeira do Teotônio. Os desembarques pesqueirosforam monitorados diariamente em 15 portos e/ou comunidades ribeirinhas, usando entrevistassemiestruturadas com os pescadores. Com dados do Programa de Monitoramento Pesqueiro das UHEsSanto Antônio e Jirau foram analisados: a produção, a captura por unidade de esforço (CPUE), a estruturaem comprimento, os locais e os apetrechos de pesca utilizados entre 2009 e 2011. A produção da espécie foianalisada temporalmente com dados da Colônia de Pescadores de Porto Velho (Rondônia, Brasil) de 1990 a2012. A produção e a CPUE apresentaram diferenças significativas por área e localidades e a captura daespécie foi realizada, principalmente, na calha e nas margens do rio por meio de malhadeira. Verificou-setambém que os exemplares amostrados na área montante exibiram distribuição e comprimentos modaismaiores que na área jusante. Estes resultados sugerem a necessidade de estratégias de manejo distintas entreas áreas.

Co-location of passive gear fisheries in offshore wind farms in the German EEZ of the North Sea: A first socio-economic scoping.

Worldwide the renewable energy sector is expanding at sea to address increasing demands. Recently the race for space in heavily used areas such as the North Sea triggered the proposal of co-locating other activities such as aquaculture or fisheries with passive gears in offshore wind farms (OWFs). Our interdisciplinary approach combined a quantification of spatial overlap of activities by using Vessel Monitoring System and logbook data with a stakeholder consultation to conclude and verify on the actual feasibility of co-location. In the German Exclusive Economic Zone (EEZ) of the North Sea up to 90% of Danish and 40% of German annual gillnet fleet landings of plaice overlapped with areas where OWFs are developed. Our results indicated further that the international gillnet fishery could lose up to 50% in landings within the North Sea German EEZ when OWF areas are closed entirely for fisheries. No spatial overlap was found for UK potters targeting brown crab in the German EEZ. We further identified a number of key issues and obstacles that to date hinder an actual implementation of co-location as a measure in the marine spatial planning process: defining the legal base; implementation of safety regulations; delineation of minimum requirements for fishing vessels such as capacities, quotas, technical equipment; implementation of a licensing process; and scoping for financial subsidies to set up business. The stakeholder consultation verified the scientific findings and highlighted that all those points need to be addressed in a planning process. In the German EEZ we have shown that the socio-economic importance of spatial overlap varies within planning boundaries. Therefore we recommend an interdisciplinary bottom-up approach when scoping for suitable areas of co-location. Hence, an informed marine spatial planning process requires comprehensive and spatial explicit socio-economic viability studies factoring in also ecological effects of OWFs on target species.

Impact of metal pollution, food availability, and excessive fishing on Rhabdosargus haffara stock (family: Sparidae) in Timsah lake.

The lakes' fisheries play an important role in Egyptian economy. In 1980s, they provided more than 50 % of harvested fish in Egypt but now their contribution to the Egypt fish production decreased to only 12.5 % in 2012. Lake Timsah, one of the Suez Canal lakes, faced many challenges that lead to serious changes in its water and fish quality, fish production, as well as the catch composition. The present work investigated the impact of pollution, food availability, and excessive fishing mortality on the haffara production in lake Timsah. The distribution of four heavy metals (Pb, Zn, Ni, and Fe) was detected seasonally in water and in muscles, gills, and livers of Rhabdosargus haffara, during 2012 through 2013. Fe and Zn were presented by high values in liver, while Pb and Ni in gills. Generally, the lowest concentrations of all metals were found in muscles. The recorded crustacean organisms (the main food of haffara) decreased from 12 species and 32,079 organisms/m(2) in 2012 to only 7 species and 7290 organisms/m(2) in 2013 while the amphipods completely disappeared. This serious change was due to the severe pollution in the lake. A logistic surplus production model was fitted to the catch per unit effort indices, to estimate the maximum sustainable yield and the optimum level of fishing effort. The results revealed that haffara stock at lake Timsah is overfished, and the estimated precautionary target reference points advised the reduction of fishing effort by about 30-50 %.

High-resolution photo-mosaic time-series imagery for monitoring human use of an artificial reef.

Successful marine management relies on understanding patterns of human use. However, obtaining data can be difficult and expensive given the widespread and variable nature of activities conducted. Remote camera systems are increasingly used to overcome cost limitations of conventional labour-intensive methods. Still, most systems face trade-offs between the spatial extent and resolution over which data are obtained, limiting their application. We trialed a novel methodology, CSIRO Ruggedized Autonomous Gigapixel System (CRAGS), for time series of high-resolution photo-mosaic (HRPM) imagery to estimate fine-scale metrics of human activity at an artificial reef located 1.3 km from shore. We compared estimates obtained using the novel system to those produced with a web camera that concurrently monitored the site. We evaluated the effect of day type (weekday/weekend) and time of day on each of the systems and compared to estimates obtained from binocular observations. In general, both systems delivered similar estimates for the number of boats observed and to those obtained by binocular counts; these results were also unaffected by the type of day (weekend vs. weekday). CRAGS was able to determine additional information about the user type and party size that was not possible with the lower resolution webcam system. However, there was an effect of time of day as CRAGS suffered from poor image quality in early morning conditions as a result of fixed camera settings. Our field study provides proof of concept of use of this new cost-effective monitoring tool for the remote collection of high-resolution large-extent data on patterns of human use at high temporal frequency.

Artisanal fisheries of the Xingu River basin in Brazilian Amazon

Abstract The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the regions fisheries, with emphasis on the contribution of the motorised canoes powered by long-tail outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher1.day1, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the regions fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River.

Resumo Este trabalho teve como objetivo caracterizar a pesca comercial de consumo na bacia do rio Xingu, afluente do rio Amazonas, no trecho entre a cidade de Gurupá (localizada na foz do Rio Amazonas) até São Félix do Xingu, no estado do Pará, Brasil. No período de abril de 2012 a março de 2014 foram registradas 23.939 viagens de pesca, totalizando uma produção de 1.484 toneladas de pescado, obtidas por quase 3.000 pescadores. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando-se a participação de canoas motorizadas que utilizam um motor de popa chamado rabeta. Os barcos motorizados atuam somente na foz do rio Xingu e no rio Amazonas. Tucunaré (Cichla spp), pescada-branca (Plagioscion spp), pacu (várias espécies de Serrasalmidae), aracu (várias espécies de Anostomidae) e curimatã (Prochilodus nigricans) perfazem mais de 60% do total capturado. A captura média por unidade de esforço é de 18 kg.pescador1.dia1 e muda dependendo da modalidade de pesca (tipo de embarcação e arte de pesca), do pesqueiro utilizado e da época do ano. Na maior parte dos casos, não encontramos diferenças nos rendimentos de 2012 e 2013. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras mudanças que possam ocorrer na atividade frente à construção da barragem de Belo Monte no Rio Xingu.

Artisanal fisheries of the Xingu River basin in Brazilian Amazon / Pescarias artesanais da bacia do Rio Xingu na Amazônia Brasileira

The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the region’s fisheries, with emphasis on the contribution of the motorised canoes powered by “long-tail” outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher–1.day–1, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the region’s fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River.

Este trabalho teve como objetivo caracterizar a pesca comercial de consumo na bacia do rio Xingu, afluente do rio Amazonas, no trecho entre a cidade de Gurupá (localizada na foz do Rio Amazonas) até São Félix do Xingu, no estado do Pará, Brasil. No período de abril de 2012 a março de 2014 foram registradas 23.939 viagens de pesca, totalizando uma produção de 1.484 toneladas de pescado, obtidas por quase 3.000 pescadores. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando-se a participação de canoas motorizadas que utilizam um motor de popa chamado “rabeta”. Os barcos motorizados atuam somente na foz do rio Xingu e no rio Amazonas. Tucunaré (Cichla spp), pescada-branca (Plagioscion spp), pacu (várias espécies de Serrasalmidae), aracu (várias espécies de Anostomidae) e curimatã (Prochilodus nigricans) perfazem mais de 60% do total capturado. A captura média por unidade de esforço é de 18 kg.pescador–1.dia–1 e muda dependendo da modalidade de pesca (tipo de embarcação e arte de pesca), do pesqueiro utilizado e da época do ano. Na maior parte dos casos, não encontramos diferenças nos rendimentos de 2012 e 2013. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras mudanças que possam ocorrer na atividade frente à construção da barragem de Belo Monte no Rio Xingu.

Artisanal fisheries of the Xingu River basin in Brazilian Amazon / Pescarias artesanais da bacia do Rio Xingu na Amazônia Brasileira

Abstract The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the region’s fisheries, with emphasis on the contribution of the motorised canoes powered by “long-tail” outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher–1.day–1, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the region’s fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River.

Resumo Este trabalho teve como objetivo caracterizar a pesca comercial de consumo na bacia do rio Xingu, afluente do rio Amazonas, no trecho entre a cidade de Gurupá (localizada na foz do Rio Amazonas) até São Félix do Xingu, no estado do Pará, Brasil. No período de abril de 2012 a março de 2014 foram registradas 23.939 viagens de pesca, totalizando uma produção de 1.484 toneladas de pescado, obtidas por quase 3.000 pescadores. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando-se a participação de canoas motorizadas que utilizam um motor de popa chamado “rabeta”. Os barcos motorizados atuam somente na foz do rio Xingu e no rio Amazonas. Tucunaré (Cichla spp), pescada-branca (Plagioscion spp), pacu (várias espécies de Serrasalmidae), aracu (várias espécies de Anostomidae) e curimatã (Prochilodus nigricans) perfazem mais de 60% do total capturado. A captura média por unidade de esforço é de 18 kg.pescador–1.dia–1 e muda dependendo da modalidade de pesca (tipo de embarcação e arte de pesca), do pesqueiro utilizado e da época do ano. Na maior parte dos casos, não encontramos diferenças nos rendimentos de 2012 e 2013. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras mudanças que possam ocorrer na atividade frente à construção da barragem de Belo Monte no Rio Xingu.

Dinámica espacio-temporal del esfuerzo en una pesquería de buceo artesanal multiespecífica y sus efectos en la variabilidad de las capturas: Implicaciones para el manejo sostenible / Spatio-temporal dynamics of fishing effort in a multi-species artisanal diving fishery and its effects on catch variability: Insights for sustainable management

Artisanal diving fisheries are a source of income, employment and food security of coastal areas in many countries. Understanding the dynamics of these fisheries, including the spatial and temporal dynamics of fishing effort, gears and species can help to address the challenges involved in fisheries management. We aimed to analyze the differences in fishing strategies under- taken by fishers that use two different diving methods (hookah and free diving), the conditions and their potential impacts on catches when adjustments to those strategies are applied over time. For this, detailed information of fishing operations from artisanal boats in the North Pacific coast of Costa Rica was analyzed in two fishing seasons (2007-2008 and 2011-2012). Data were collected by onboard observers (fishing site, fishing time, species composition, depth and visibility). Additionally, interviews with divers were applied to obtain information of price per species, species volume and fishing operations. From the total number of trips during both seasons, hookah diving was represented by a sample size of 69.3%, while free diving, with a sample of 41.9%. More than 15 species were identified in each fishing season. Nevertheless, three categories had substantial contributions in both seasons with differences in the proportions for each case: green lobster (Panulirus gracilis), octopus (Octopus sp.) and parrotfish (Scarus perrico and S. ghobban). It is worth noting that an important proportion of catch was retained by fishers for personal consumption purposes, including species of high commercial value. Additional night diving activity, increased the number of dives from one season to another. Besides, cooperation processes in free diving fishing operations, and changes in fishing effort between seasons, defined important changes in fishing strategies. Potential causes of changes in fishing strategies and the implications for manage- ment to ensure the sustainability of these fisheries in the long term are discussed.

Las pesquerías artesanales asociadas a métodos de buceo son fuente de ingreso, empleo y seguridad alimentaria de zonas costeras en muchos países. Los altos precios y la poca movilidad de especies bénticas capturadas por buceo enfrentan retos cada vez mayores en su aprovechamiento y manejo, esto demanda un entendimiento integral de estas pesquerías en diferentes contextos, incluyendo la dinámica espacial y temporal del esfuerzo pesquero, las artes y las especies. En el presente estudio se busca elucidar si existen diferencias en las estrategias de pesca desarrolla- das por pescadores que emplean buceo en dos modalidades (hookah y buceo libre). También se busca conocer si se desarrollan adaptaciones de estas estrategias en el tiempo, bajo qué condiciones y el posible efecto de las estrategias sobre las capturas. Para ese fin se analizó información detallada de las operaciones de pesca de embarcaciones artesanales que operan en la costa del océano Pacífico de Costa Rica durante dos temporadas de pesca. Se analizó información obtenida a bordo de embarcaciones como: sitio de pesca, composición de especies, tiempo de pesca, número de inmersiones por viaje, entre otros; y se aplicaron entrevistas a buzos al momento de las descargas para obtener información de precios, el volumen de las especies capturadas y forma de operación de los pescadores. Para el buceo con hookah se obtuvo una muestra del 69.3% del total de viajes en las dos temporadas de pesca y en el caso del buceo libre se obtuvo una muestra del 41.9% del total de viajes en las dos temporadas de pesca estudiadas (2007-2008 y 2011-2012). Se identificaron más de 15 especies en cada temporada de pesca, dominaron tres categorías en ambas temporadas pero con diferencias en las proporciones obtenidas en cada caso: langosta (Panulirus gracilis), pulpo (Octopus sp) y pez loro (Scarus perrico y S. Ghobban). Resalta un componente importante de captura retenida por los pescadores para consumo personal, incluyendo especies de alto valor comercial. Se identificaron cambios en las estrategias de pesca asociadas a cambios en las capturas y cambios en la asignación espacial del esfuerzo pesquero de una temporada de pesca a otra, definidas por la adición de buceo nocturno, aumento en el número de inmersiones de una temporada a otra y procesos de cooperación en las faenas de pesca de buzos que usan buceo libre. Se discute las potenciales causas de los cambios en las estrategias de pesca observadas y se derivan implicaciones para el manejo que permiten la sostenibilidad de estas pesquerías a largo plazo.

Análisis de la pesquería del jurel Trachurus murphyi en el Perú

La presencia del jurel Trachurus murphyi ha sido registrado en los desembarques de la pesca artesanal en Perú desde 1907. A partir del año 2000, las capturas de T. murphyi se ubicaron en el tercer lugar después de la anchoveta Engraulis ringens y el calamar gigante Dosidicus gigas. Las capturas de T. murphyi son realizadas por la flota artesanal, industrial cerquera y barcos arrastreros factoría. En el año 2011, la flota industrial cerquera con permiso de pesca para T. murphyi en la costa peruana estaba constituida por 62 embarcaciones industriales de acero (30177 m³) y 42 industriales de madera (3082 m³). Las capturas de T. murphyi tuvieron un notable incremento a partir de 1972, alcanzando sus máximos valores en 1977, 1996-97 y 2001, a los que siguieron años de muy baja disponibilidad que llevó al mínimo registro en las capturas en 2010. Sin embargo en el 2011 se revirtió esta baja disponibilidad y las capturas alcanzaron casi las 260000 toneladas. En el periodo 1972 - 2012 se observó una relación inversa entre los estimados de biomasa acústica del jurel T. murphyi y los desembarques anuales de anchoveta E. ringens. Las capturas mensuales de T. murphyi por la flota industrial y artesanal antes del 2002 fueron altas en la zona norte de Perú (Mancora-Chimbote), mientras que después del 2002 las capturas fueron altas en la zona centro-sur (Huacho-Ilo).

There are records of the presence of Jack mackerel Trachurus murphyi in the artisanal fishery landings in Peru since 1907. Since 2000 Jack mackerel T. murphyi catches are ranked third after anchovy Engraulis ringens and jumbo squid Dosidicus gigas. Artisanal, industrial purse seine and offshore (factory trawlers) fleets take part in the Peruvian catches of T. murphyi. In 2011 the industrial purse-seine fleet with license to fish for T. murphyi along the Peruvian coast comprised of 62 industrial steel vessels (30177 m³) and 42 industrial wood vessels (3082 m³). Catches of T. murphyi had a significant increase after 1972, with maximum catches in 1977, 1996-97 and 2001, after which several years of low availability followed, with the lowest catches in 2010. However, this low availability trend was reversed in 2011, and catches reached almost 260 thousand tons that year. A general inverse relationship has been observed between the T. murphyi estimated acoustic biomass and the annual landings of anchovy E. ringens during the the period 1972 - 2012. The monthly catches of T. murphyi by the industrial and artisanal fleets before 2002 were higher in the northern part of Peru (Mancora-Chimbote) while after 2002 the catches were higher in the south-central zone (Huacho-Ilo).

A pesca comercial na bacia do rio Madeira no estado de Rondônia, Amazônia brasileira / The Commercial fisheries of the Madeira river basin in the Rondônia state, brazilian Amazon

Este estudo caracteriza quali e quantitativamente a atividade pesqueira comercial na bacia do rio Madeira, afluente do rio Amazonas, no trecho entre Guajará-Mirim e Porto Velho, estado de Rondônia. No período de janeiro a dezembro/2004, foram registrados 460 t, correspondendo 935 viagens. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando a maior participação das canoas motorizadas (131 unidades) do que barcos pesqueiros (45 unidades; capacidade média: 3.000kg) na frota pesqueira. Os peixes migradores jaraqui (Semaprochilodus spp.), dourada (Brachyplatystoma rousseauxii), sardinha (Triportheus spp.), jatuarana/matrinxã (Brycon amazonicus e B. cephalus), curimatã (Prochilodus nigricans) e filhote (Brachyplatystoma filamentosum) se destacaram na composição das espécies desembarcadas. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras variações que possam ocorrer na atividade frente aos impactos dos empreendimentos hidrelétricos em construção na região.

This study presents qualitative and quantitative information about commercial fishery in the basin of the Madeira River, tributary of the Amazon River, describing the fishing activity in the segment between Guajará-Mirim and Porto Velho, in Rondônia State. From January to December/2004, 219 fishermen and 935 trips were registered, corresponding to the capture of 460 t of fish. Data from fish landings demonstrate that fisheries in the region are small-scaled and point to a higher participation of small motorized canoes (130 units) than of fishing boats (45 units; average capacity: 3000 kg) in the fishing fleet. Migratory species like jaraqui (Semaprochilodus spp.), dourada (Brachyplatystoma rousseauxii), sardinha (Triportheus spp.), jatuarana/matrinxã (Brycon amazonicus e B. cephalus), curimatã (Prochilodus nigricans) and filhote (Brachyplatystoma filamentosum) were the most important in terms of landings. The technical information produced are very important in order to subsidize fishery management, as well as to assess future variations that might happen due to the hydro-electric enterprises under construction in the region.