AquaDocs
Not a member yet
36984 research outputs found
Sort by
SAMUDRA Report No.91, June 2024
No full textThe International Collective in Support of Fishworkers (ICSF) has just published the latest issue of SAMUDRA Report, its triannual journal on fisheries, communities and livelehoods. The current edition, SAMUDRA Report No. 91, dated June 2024, is a Special Issue that runs into 110 pages and features a diverse range of articles from several countries like Japan, Vietnam, India, Sri Lanka, China, Chile and Brazil, among others. A special focus of the issue is the Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries in the Context of Food Security and Poverty Eradication (the SSF Guidelines) and the process of its implementation in different countries. Also in the spotlight is the 2nd SSF Summit designed to commemorate the 10th anniversary of the SSF Guidelines. The Summit is expected to attract up to 300 people primarily representative of not just small-scale fisheries organizations and movements, but also inter-governmental organizations, NGOs and governments, taking into account regional, gender and age balances. The editorial Comment in SAMUDRA Report No. 91 focuses on how a wide range of actors— from civil society organizations to grassroots activists and trade unionists—are rallying around a human rights-based approach to tackle issues plaguing the SSF subsector. The 40th anniversary of the International Conference of Fishworkers and their Supporters (the 1984 Rome Conference) is commemorated in an article titled “Rallying for Collectivism”, while the implementation of the SSF Guidelines is detailed in various country reports that demonstrate how SSF combat poverty, enhance food security and promote sustainable resource use through National Plans of Action. Tenure rights systems that are primarily responsible for the sustainability of fisheries are illustrated in reports from Japan, India, Sri Lanka and China, while a piece from the US shows how permit banks and collective ownership in Alaska return individual fishing rights to the collective. The article from Brazil describes how artisanal fishing communities in the Amazon struggle to maintain traditional ways of life, while another article talks of how ‘parliaments of the sea’ in France can ensure both co-management of marine areas and protection of fishers’ rights. Targeted initiatives can address the systemic inequalities in the fisheries sector of Bangladesh, argues another article, while climate change is the subject of the piece from Antigua and Barbuda which argues that the Caribbean island nation must make its SSF community resilient to the effects of climate-related occurences. A report on a workshop on Latin America and the Caribbean highlights the participants’ global Call for Action for sustainable and equitable small-scale fisheries. A piece on the SSF-LEX database provides information on the legal frameworks governing SSF, while another on the South Pacific Islands points to the relevance of parametric insurance in protecting SSF from the increasing risks of climate change. From Ghana comes an article on the Sankofa Project which investigates the gendered socioeconomic effects of fisheries closures, while a scientific analysis of spawning periods of marine fish resources in India reveals crucial geospatial differences. The recent instances of extreme flooding in Brazil highlights the vulnerability of small-scale fishers to climate-induced disasters, points out another article. The last article in SAMUDRA Report No. 91 is on the L’orient Film Festival in France, a regular affair that stresses how fishing is vital for ocean biodiversity and community livelihoods. The Roundup section of SAMUDRA Report No. 91 carries news snippets, event announcements, briefings on fishery-related matters, and more. SAMUDRA Report No. 91 can be accessed at: https://www.icsf.net/samudra-articles.php?id=10140PublishedReferee
Study of some ecological parameters in nematode parasites of freshwater fish in the Senegal and Gambia rivers
No full textThis study was conducted in the rivers of Senegal and the Gambia over three consecutive years, during both dry and wet periods. A total of 1216 fish were sampled during this period, with 551 from Gambia and 665 from Senegal. The fish were classified into 29 species. Chrysichthys maurus Valenciennes, 1840 is the host fish with the broadest spectrum of parasites, with Procamallanus and Contracaecum being the most common genera of nematodes. Chrysichthys maurus Valenciennes, 1840, Clarias gariepinus Burchell, 1822, Synodontis annectens Boulenger, 1911, and Synodontis nigrita Cuvier et Valenciennes, 1840 exhibit the highest biodiversity indices, which vary depending on the seasons and sex of the fish. The overall prevalence of fish parasites varies by locality and sex. Only Citharinus citharus Geoffroy Saint-Hilaire, 1809 shows significant differences in weight and size, with respective values of 6.3e-08 and 0.01653.PublishedReferee
State of the Ocean Report 2024.
No full textThe State of the Ocean Report (StOR) has the ambition to inform policymakers about the state of the ocean and to stimulate research and policy actions towards ‘the ocean we need for the future we want’, contributing to the 2030 Agenda and in particular SDG 14, which reads ‘Conserve and sustainably use the oceans, seas and marine resources’, as well as other global processes such as the UNFCCC, the Convention on Biological Diversity and the Sendai Framework for Disaster Risk Reduction. Structured around the seven UN Decade of Ocean Science for Sustainable Development Outcomes, the Report provides important information about the achievements of the UN Ocean Decade and, in the longer term, about ocean well-being. The StOR will be used to inform policy and administrative priorities and identify research focus areas that need to be strengthened or developed.PublishedReferee
Avaliando a poluição plástica em ecossistemas brasileiros: um estudo integrado da poluição em organismos e ambientes.
No full textPlastics are pervasive contaminants worldwide, accumulating from the poles to the equator, spanning pristine environments to deep ocean basins.This workexplores how seasonal variations in a floodplain influence the ingestion of plastics by freshwater fish and systematically examines trends and gaps in Brazilian research related to plastic pollution.Additionally, the potential relationship between anthropogenic activities and the amounts of plastic found in Brazilian aquatic environmentswas investigated.Among the 23 fish species analyzed in the Upper Paraná River floodplain, nine were ingested plastics, and the particles were associated with fishingactivity and domestic waste. Seasonality played a crucial role in the amounts of plastic ingested by these species, with the highest number of particles recorded during the wet season. As for trends and gaps in Brazilian research on plastic pollution, a substantial number of publications related to marine environments, microplastics, and fishwas identified. Conversely, freshwater environments and invertebrates are underexplored.Considering the distribution of studies within Brazilian biomes, the Pantanaland Cerrado had the lowest number of publications—an alarming trend considering the significant rivers and basins they house.Finally, themodels were unable to find strong and significant correlations between the number of plastics and anthropogenic activities in Brazilian municipalities.The lack of significant relationships may be attributed to the limitations of our dataset, specificallydue to the low number of studies.Nevertheless, other factors influenced the quantities of plastic detected.In biotic samples, the number of ingested plastics was influenced by the animal group, with reptiles, birds, and fish being the most affected groups. For abiotic samples, the type of environment emerged as a significant factor.In sediment samples, the quantity of plastics was higher in estuarine and freshwater environments. In water samples, the quantity of plastics was higher exclusively in freshwater environments.The finds of this workcontribute to new research on plastic pollution in Brazilian aquatic environments, expanding theunderstanding of the dynamics of plastics in freshwater environments and their interaction with various organisms.Plásticos são contaminantes onipresentes no planeta, acumulando-se dos polos ao equador, desde ambientes pristinos em grandes altitudes até bacias oceânicas profundas. Investigou-se como a ingestão de plásticos por peixes de água doce é influenciada pelas variações sazonais de uma planície de inundação, bem como as tendências e lacunas da pesquisa brasileira em relação a poluição plástica. Investigou-se também a possível relação entre atividades antropogênicas e as quantidades de plástico encontradas nos ambientes aquáticos brasileiros. Das 23 espécies de peixes analisadas na planície de inundação do alto rio Paraná, nove ingeriram plásticos, e as partículas encontradas são associadas com a atividade pesqueira e o lixo doméstico. A sazonalidade promovida pelo ciclo hidrológico desempenhou um papel importante nas quantidades de plásticos ingeridas por essas espécies, onde o maior número de partículas foi registrado durante o período de cheias. Em relação as tendências e lacunas da pesquisa brasileira sobre a poluição plástica, encontrou-se um grande número de publicações para ambientes marinhos, microplásticos e peixes. Ambientes de água doce e invertebrados permanecem pouco estudados no país. Considerando a distribuição dos estudos dentro dos biomas brasileiros, Pantanal e Cerrado foram os biomas com o menor número de publicações, um fato preocupante visto os importantes rios e bacias que estes abrigam. Por fim, os modelos não encontraram correlações entre a quantidade de plásticos e as atividades antropogênicas dos municípios brasileiros. A ausência dessas relações pode estar relacionada às limitações do conjunto de dados, especificamente devido ao baixo número de estudos com dados disponíveis. Entretanto, outros fatores influenciaram as quantidades de plásticos encontradas. Em amostras bióticas, o número de plásticos ingeridos esteve associado ao grupo animal, sendo os répteis, aves e peixes os mais afetados. Para amostras abióticas, o tipo de ambiente foi um fator influente. Em amostras de sedimento o número de plásticos foi maior para ambientes estuarinos e de água doce. Para as amostras de água, o número de plásticos foi maior apenas para ambientes de água doce. Devido aos efeitos negativos da poluição plástica e à importância econômica e ecológica das espécies afetadas, os resultados desse estudo representam um passo importante na avaliação dos impactos gerados nas populações de peixes de água doce pela ingestão de plásticos. Espera-se que estes resultados contribuam para o direcionamento de novas pesquisas em relação a poluição plástica nos ambientes aquáticos brasileiros, e que estes estudos expandam nosso conhecimento sobre a dinâmica dos plásticos em ambientes de água doce, assim como sua interação com diferentes organismos.Ph
Population Dynamics of Perna perna (Linnaeus, 1758) from Dakar Coastal Waters, Senegal
No full textPerna perna is a species of bivalve mollusk found along the Senegalese coast from the Cape Verde peninsula to the Saloum Islands. Due to the generation of income and jobs, this species is extremely significant to Senegal’s socioeconomic landscape, especially in the Dakar area. This work constitutes a first study on the population dynamics of Perna perna in Senegal. The specimens used for this study were caught in the Mamelles site on the Cape Verde Peninsula from March 2018 to February 2019. To assess population parameters, the FiSAT II software and its ELEFAN sub-program were used to analyze the monthly length-frequency data. The results obtained show that the asymptotic length (L∞), growth coefficient (K), growth performance index (Φ’) and longevity (tmax) were 13.65 cm, 1 yr-1, and 2.27; 2.80 yr, respectively. Total mortality (Z) was esteemed to be 3.51 yr-1. Natural mortality (M) and fishing mortality (F) were 2 yr-1 and 1.51 yr-1, respectively. The recruitment pattern is a continuous with a major peak occurring in May-Jun. The current exploitation level (E) of Perna perna was 0.43 while the maximum allowable limit of exploitation (Emax) was 0.453; which implies that in order to prevent overexploitation, management actions will need to be taken. Keywords: Perna perna, Senegal, Cape Verde, population dynamcsPublishedReferee
Reproduction and minimal sizes for commercial sponges catches: aims for incrementing Cuban’s sponges culture.
No full textEl desconocimiento de los procesos reproductivos y la talla de madurez sexual de las esponjas comerciales de baño (familia Spongiidae) en Cuba constituye, actualmente, una limitante para el adecuado manejo de la pesquería de estas especies. El objetivo de esta revisión fue compilar la información existente sobre reproducción de esponjas comerciales, experiencias de repoblación basados en sistemas de cultivo, y el establecimiento de tallas mínimas de captura. La información acumulada posibilitó identificar vacíos en el conocimiento regional, inferir tallas límite para regular la actividad extractiva en Cuba y elaborar una propuesta de medidas coyunturales que minimicen el riesgo del colapso en la pesquería cubana de esponjas. Se comprobó que urge la realización de estudios histológicos, citológicos y de supervivencia larval en las especies cubanas. Además, se corroboró que una talla mínima legal de 15 cm de diámetro mayor se corresponde con los estándares internacionales actualmente establecidos para esponjas comerciales de otras regiones y, por tanto, contribuiría a mejorar el rendimiento pesquero sin mayores afectaciones al potencial reproductivo de las poblaciones en explotación. Sin embargo, la extracción de esponjas menores (a 15 cm de diámetro mayor) podría hacer colapsar la población por generar fallas en el reclutamiento y afectaciones desconocidas en los procesos reproductivos poblacionales. La implementación definitiva del cultivo de esponjas a escala nacional es la solución más plausible y biológicamente aceptable para la obtención de las esponjas de pequeña talla, que satisfacen de mejor manera las actuales demandas del mercado internacional.The lack of knowledge about the reproductive processes and the size of sexual maturity of commercial bath sponges (Family Spongiidae) in Cuba, currently constitutes a limitation to develop adequate management and conservation plans in the fishery of these species. This review aimed to summarize the existing information on the reproduction of commercial sponges, repopulation experiences based on farming systems, and the establishment of minimum capture sizes. These data helped to identify the main gaps in regional knowledge, to infer size limit to regulate extractive activity in Cuba, and to prepare conjunctural measures that minimize the risk of collapse in the Cuban sponge’s fishery. It was concluded that it is urgent the need of histological, cytological, and larval survival studies in Cuban species. In addition, it was confirmed that a legal minimum size of 15 cm in largest diameter corresponds to the international standards currently established for commercial sponges from other regions and, therefore, would contribute to improving fishing yield without further affecting the reproductive potential of populations in exploitation. However, the extraction of smaller individuals (with a largest diameter of 15 cm or smaller) could cause the population to collapse due to recruitment failures and unknown effects on population reproductive processes. The definitive implementation of sponge culture on a national scale is the most plausible and biologically acceptable solution for obtaining small-sized sponges, which better satisfy the current demands of the international market.PublishedReferee
Elevage du tilapia du Nile (Oreochromis niloticus) en système biofloc: suivi des paramètres du milieu et des performances.
No full textThe aim of this work is to investigate the evolution of the water quality parameters during the maturation phase, and to evaluate the growth performance and feed utilization efficiency of Nile tilapia raised in a biofloc system (BFT) with carbon/nitrogen (C/N) ratios of 12 and 18. The results of this study indicate that the maturation phase of the biofloc can last up to 6 weeks and is characterized by peaks in ammonium and nitrite concentrations, a decrease in alkalinity, and an accumulation of suspended solids. Growth performance and feed utilization were similar between tilapia raised in clear water and those in BFT system. However, in the BFT groups, a decrease in tilapia growth is observed with increasing C/N ratio from 12 to 18. Overall, the BFT system has no negative effects on the growth performance and feed utilization efficiency of tilapia.Références bibliographiques, Tableaux, Figures.PublishedReferee
Journal of Marine Studies (JoMS): A new open access journal in ocean science and technology
No full textPublishedReferee
Disentangling the relative roles of anthropogenic stressors in modeling the taxonomic and functional diversity of aquatic zooplâncton: an experimental approach.
No full textThe conservation of freshwater ecosystems is a central theme in ecological studies, considering their importance for global environmental integrity. These ecosystems face several threats from human activities that contribute to the increase in temperature and nutrient enrichment in water bodies, generating substantial and cumulative impacts in these environments. Such impacts have the potential to alter trophic chains and the general structure of communities in freshwater ecosystems, which harbor a high taxonomic and functional diversity of zooplankton (i.e., metazoans and protozoa) whose role is crucial in ecosystem functioning. The general objective is to evaluate the possible effects of isolated and combined anthropogenic stressors on important diversity attributes of zooplankton communities (i.e., taxonomic richness, functional richness and abundance) in freshwater environments, in addition, to investigate the possible effects of these stressors on interaction between species (e.g., predation/competition). The central hypothesis suggests that warming and nutrient enrichment would lead to a decrease in taxonomic and functional richness, an increase in abundance and changes in zooplankton interactions, as well as their composition. The topics covered in this thesis provide a comprehensive analysis of these effects, contributing to the understanding of the determining factors in the structuring of zooplankton communities and offering important conclusions for future conservation strategies in the face of warming and eutrophication scenarios in freshwater bodies.A conservação dos ecossistemas de água doce é um tema central em estudos ecológicos, considerando sua importância para a integridade ambiental global. Esses ecossistemas enfrentam diversas ameaças de atividades antrópicas que contribuem para o aumento da temperatura e o enriquecimento por nutrientes em corpos d'água, gerando impactos substanciais e cumulativos nesses ambientes. Tais impactos apresentam potencial de alterar as cadeias tróficas e a estrutura geral das comunidades dos ecossistemas de água doce, os quais abrigam uma elevada diversidade taxonômica e funcional do zooplâncton (i.e., metazoários e protozoários) cujo papel é crucial no funcionamento ecossistêmico. O objetivo geral consiste em avaliar os possíveis efeitos de estressores antropogênicos isolados e combinados sobre importantes atributos de diversidade das comunidades do zooplâncton (i.e., riqueza taxonômica, riqueza funcional e abundância) de ambientes de água doce, outrossim, averiguar os possíveis efeitos desses estressores na interação entre as espécies (e.g., predação / competição). A hipótese central sugere que o aquecimento e o enriquecimento por nutrientes levariam à diminuição da riqueza taxonômica e funcional, aumento da abundância e alterações nas interações do zooplâncton, bem como em sua composição. Os tópicos abordados nesta tese fornecem uma análise abrangente desses efeitos, contribuindo para a compreensão dos fatores determinantes na estruturação das comunidades zooplanctônicas e oferecendo conclusões importantes para estratégias de conservação futura frente aos cenários de aquecimento e eutrofização em corpos de água doce.Ph
Explorando la depredación por perforación en moluscos marinos: perspectivas en las dinámicas depredador-presa y presiones selectivas en ensambles de conchas de gasterópodos de Playa Guardalavaca, Cuba.
No full textPredation marks by drilling molluscs serve as evidence for feeding activity. This behaviour has been extensively studied to understand predator-prey relationships. The objective of this study is to characterise the mollusc drilling predation on gastropods from Playa Guardalavaca, Cuba. We examined the species richness and abundance of drilled and non-drilled shells and calculated predation rates and its relationship with prey size. To compare drilled and non-drilled shells, we used the median and interquartile range due to the asymmetric distribution of the measurements. Furthermore, we employed a Kolmogorov-Smirnov test to compare the size distribution frequencies. A total of 114 morphospecies and nine species groups were identified. Five species were identified as new records for the area. A total of 5,795 shells were quantified, out of which 24.4% displayed drillholes. The most abundant species are not the most preyed upon, presenting a distinct pattern compared to bivalve assemblages in this and other locations. The highest predation rate was observed among individuals of medium size, may be attributed to the predators' ability to manipulate their prey. Smaller shells may not offer sufficient food resources, resulting in lower predation rates. Statistical analyses revealed significant differences in predation related to shell size for six out of the 11 tested species. Potential predators were identified, some of which exhibit drillholes themselves. In general, drilling predation in gastropods from the studied area appears to be influenced by a combination of factors, including high species richness of both predators and prey, prey abundance, specialised feeding strategies of predators, and habitat diversity.Las marcas de depredación por perforación de moluscos sirven de evidencia de la actividad alimentaria. Este comportamiento ha sido extensamente estudiado para comprender las relaciones depredador-presa. El objetivo de este estudio es caracterizar la depredación por perforación de moluscos gasterópodos de Playa Guardalavaca, Cuba. Se examinó la riqueza de especies y abundancia de conchas perforadas y no perforadas y se calculó la tasa de depredación y su relación con el tamaño de las presas. Para comparar las conchas perforadas y no perforadas se utilizó la mediana y el rango intercuartil dada la distribución asimétrica de las mediciones. Además, se empleó una prueba de Kolmogorov-Smirnov para comparar las frecuencias de distribución de tamaño. En total 114 morfoespecies y nueve grupos de especies fueron identificadas. Cinco especies fueron identificadas como nuevos registros para el área. Se cuantificaron 5 795 conchas, de las cuales 24,4 % presentaron perforaciones. Las especies más abundantes no son las más depredadas, presentando un patrón distinto comparado con los ensambles de bivalvos en esta y otras localidades. La mayor tasa de depredación fue observada entre individuos de tamaño medio, atribuido a la habilidad de los depredadores para manipular sus presas. Conchas pequeñas podrían no ofrecer suficiente alimento, resultando en tasas de depredación menores. Los análisis estadísticos revelaron diferencias significativas de depredación en relación al tamaño de la concha en seis de las 11 especies evaluadas. Depredadores potenciales fueron identificados, algunos de los cuales también mostraron perforaciones. En general, la depredación por perforación en los gasterópodos del área estudiada parece estar influenciada por una combinación de factores, incluyendo la alta riqueza de especies de depredadores y presas, la abundancia de las presas, estrategias especializadas de alimentación de los depredadores y la diversidad de hábitats.PublishedReferee