Inventory, description and analysis of fishing gear and techniques used in Lake Ahémé and its channels, facing the law on fishing in Benin (West-Africa)

Located in the southwest of Benin, the study environment consists of Lake Ahémé, the Ahô channel, the Tihimey channel, the coastal lagoons of Grand-Popo and Ouidah. The mouth of Avlo-plage makes the area an Estuarine Lagoon environment rich in ichthyofaunal biodiversity where fishing, the main activity of the populations, is practiced with various gears and techniques which are inventoried and described in this study. The methodological approach adopted revolves around documentary research, field surveys through questionnaires and interviews and direct observations. The people interviewed are made up of fishermen; fish wholesalers; agents specializing in fishery production. The study environment was subdivided into 19 observation stations and the data were collected from January 2018 to December 2019. The gears were illustrated by photos and described according to the results of the documentary research and information received from the fishermen. Their variations according to the bodies of water and the stations were calculated using the Excel 2017 table. The drawn meshes of the nets were measured to the nearest millimeter. The study shows that the inventoried fishing gears and techniques include nets, lines, pots, Acadjas and trap dams (Xhas), categorized into 12 gears and 02 techniques, of which 86% are constant and 14% are accessories. Gbagbaloulou conical nets dominate the gear while the landing net is the least represented. The smallest mesh measured is 2mm, while the largest mesh is 25mm. The fishing gear and techniques used do not ensure rational and sustainable management of fishery resources. Faced with the damage they are causing, the Government proceeded to their systematic removal. Snail farming was initiated to diversify the activities of fishermen.

Metal Binding and Sources of Humic Substances in Recent Sediments from the Cananéia-Iguape Estuarine-Lagoon Complex (South-Eastern Brazil)

The Cananéia-Iguape estuarine–lagoon complex (São Paulo state, Brazil) is a natural laboratory to study metal binding by humic substances (HS) in subtropical settings. This transitional environment is evolving into a freshwater environment due to water input from the Ribeira River, funneled through the Valo Grande Canal (Iguape). Past mining activities in the Ribeira River basin and maritime traffic are suspected to be potential sources of trace metals in the system. In this study, the trace metal contents of Free Humic Acids (FHA), Bound Humic Acids (BHA), and Fulvic Acids (FA) extracted from sedimentary organic matter were investigated. Moreover, the sources of HS were traced using their stable carbon isotope compositions and C/N ratios. The results suggested a mixed marine–terrestrial source of FHA, BHA, and FA. Copper and Cr were the most abundant trace metals bound to HS. On average, Cu showed concentrations of 176, 115, and 37.9 μg g−1 in FHA, BHA, and FA, respectively, whereas Cr showed average concentrations of 47.4, 86.3, and 43.9 μg g−1 in FHA, BHA, and FA, respectively. Marine FHA showed the highest binding capacity for trace metals, whereas terrestrial FA derived from the decay of mangrove organic matter showed the lowest binding capacity.

Presence and concentration of polycyclic aromatic hydrocarbons (PAHs) in sediments and organisms from Tampamachoco coastal lagoon and Tuxpan River, Veracruz; México.

Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic and mutagenic properties and their main origin in the environment is the burning of fossil fuels and organic material and they are considered high priority Persistent Organic Compounds (POPs). In the present study (March and August 2018) the concentrations of the 16 priority PAHs were analyzed in sediments and organisms (fish and oysters) in the estuarine-lagoon system Tuxpan-Tampamachoco, Veracruz; Mexico.The analysis of these compounds was carried out by means of gas chromatography-FID and mass spectrometry. In March (dry season) the average concentration of PAHs in sediments was 0.86 ± 0.39 μg/g and in August (rainy season) it was 1.14 ± 0.45 μg/g. During both collections, chrysene presented the highest total concentrations and a domain of the compounds with 4 benzene rings was observed, therefore, pyrolytic sources of contribution predominated. The highest concentrations of PAHs occurred in 2 stations located in the Tuxpan riverbed and both exceeded the threshold concentration to cause adverse effects to the benthic community.The analysis of PAHs in organism tissues was carried out in 4 species of fish and one mollusk. In march, the species with the highest concentration was Bagre marinus with 88.87 μg/g and in august it corresponded to the Caranx hippos species with 26.82 μg/g and the compound determined with the highest presence was benzo(b)fluoranthene.Finally, the tendency of accumulation of PAHs in the evaluated matrices was: fish> sediments> mollusks.

Record of changes in the regionalization of Terminos Lagoon, Campeche

The Terminos Lagoon is an estuarine-lagoon ecosystem, recognized as one of the largest coastal lagoons in the Gulf of Mexico, has great ecological, social and economic relevance, being a place from which various activities of commercial importance are carried out, in addition to being an area that presents high diversity. However, in the last 20 years it has been influenced by anthropic and natural impacts, which modifies the physicochemical characteristics of the water (temperature, salinity and pH) and changes in diversity species, being decisive in changes in regionalization. Therefore, in the present study, the spatio-temporal relationship of the physicochemical characteristics was analyzed, using geostatistics to characterize and predict possible new hydrological zones for Terminos lagoon. Samples were carried out monthly at 17 points, by zones and seasons (dry, rainy and wind/winter), in which significant differences were sought. To detect possible changes in regionalization, the GS+ software was used, where the values ​​of R2 were considered, defining the interpolation of Minimum Curvature (R2 <0.5). For the spatial distribution, the TNTmips program was used and to restructure the current zoning, a Cluster Analysis was applied. The results indicate for rainy season higher temperature values ​​(30.59 °C), higher salinity in dry (31.78 UPS), and higher pH in the wind/winter season (7.88). In the spatial distribution, the warmest areas were shown in the Candelaria River, the most saline areas by Isla de Carmen and the highest pH ranges near Pom-Atasta. According to the previous regionalization, 4 new zones are represented, which are influenced by fresh water discharges and the intrusion of salt water that is carried within the site. Keywords: Gulf of Mexico, ecosystem, refuge area, alterations, geostatistics.

Water exchange between estuarine lagoon and sea through a narrow strait: case study of two Brazilian lagoons

&lt;p&gt;The Patos Lagoon, located in the Southern Brazil, is the largest freshwater lagoon in the World (area is 10 360 km2). It is connected with the Atlantic Ocean by a narrow strait, through which saline sea waters inflows to the lagoon and fresh waters of Patos outflows to the sea. Todos os Santos is the second large bay in the Brazil, which area is 1223 km2. It is located in the Northern Brazil, connected with Atlantic Ocean and remains saline during the whole year. Study of these basins represent difference in water exchange mechanisms between small and large estuarine lagoon.&lt;br&gt;Based on year-long in situ data from sea mooring and river gauge stations, as well as wind and precipitation reanalysis data, the influence of local meteorological and hydrological conditions on water exchange of these basins was studied.&lt;br&gt;It was revealed that the distinct seasonal variability of water exchange in Patos is defined mostly by the seasonal river discharge variability, while the variability of local atmospheric circulation does not influence it. Outflows of lagoon waters to the sea are typical during the high river discharge period, while inflows of sea waters to the lagoon are rare and occur under specific wind conditions. During the low river discharge periods, inflows of sea waters to the lagoon are typical, while short-term outflows are induced by increase of river discharge.&lt;br&gt;Meantime, it was found that synoptical salinity variation in Todos-os-Santos is mostly caused by tides, while seasonal water exchange variability is almost generally wind-driven.&amp;#160;&lt;/p&gt;

Variation in size distribution of juvenile pink shrimps Farfantepenaeus brasiliensis and F. paulensis in the estuarine-adjacent ocean area of Cananéia, south-eastern coast of Brazil

The study characterized the structure of juveniles and sub-adults of Farfantepenaeus brasiliensis and F. paulensis in the Cananéia-Iguape estuarine lagoon system and its adjacent coastal area by evaluating the period of juvenile recruitment, sex ratio, growth, longevity, natural mortality, and development time until the late juvenile phase. Samples were collected from July 2012 to June 2014. Shrimps were identified by species and sex, and measured (carapace length – CL mm); 889 individuals of F. brasiliensis and 848 of F. paulensis were analysed. Females were more abundant than males for both species. The growth parameters of F. brasiliensis were: CL∞ = 45.5 mm, k = 1.8 year−1 for males and CL∞ = 55.2 mm, k = 1.6 year−1 for females; longevity of 2.52 years (males) and 2.88 years (females); and natural mortality of 1.71 (males) and 1.55 (females). For F. paulensis, the following values were observed: CL∞ = 40.7 mm, k = 2.3 year−1 for males and CL∞ = 56.5 mm, k = 1.9 year−1 for females; longevity of 2.04 years (males) and 2.37 years (females); and natural mortality of 2.39 (males) and 2.05 (females). The juvenile recruitment of both species peaked in January 2014. The development time until late juvenile phase was ~7 months (F. brasiliensis) and ~5 months (F. paulensis). Even though the highest abundance of juveniles did not occur in the closed season, fishing is forbidden in the estuarine area and the migration towards the adult population occurred close to or even during the closed season.