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Abstract

Plastic particle occurrence in the digestive tracts of fishes from a tropical estuarine system in the Gulf of Cali-fornia was investigated. A total of 1095 fish were analysed, representing 15 species. In total 1384 particles of plastic debris were recovered from the gastrointestinal tracts of 552 specimens belonging to 13 species, and all consisted of threads, the majority of which were small microplastics (0.23 to 1.89), followed by large micro-plastics (2.07 to 4.49), and few mesoplastics (5.4 to 19.86). Plastic particles were identified using ATR-FTIR spectroscopy. The mean frequency of occurrence of plastics in the gastrointestinal tracts of fishes from this system was 50.5%, which is higher than frequencies reported in similar systems in other areas. The polymers identified by ATR-FTIR were polyamide (51.2%), polyethylene (36.6%), polypropylene (7.3%), and polyacrylic (4.9%). These results show the first evidence of plastic contamination for estuarine biota in the Gulf of California.

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... Studies conducted by (Zaki et al., 2021) also found the presence of polymers. Polyamide in fish was also found in research conducted by (Salazar-Pérez et al., 2021), (Bessa et al., 2018), and (Karuppasamy et al., 2020). ...
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This study highlights for the first time the presence of plastic debris in the stomachs of Mediterranean lanternfishes (Myctophidae): Electrona risso, Diaphus metopoclampus, Hygophum benoiti and Myctophum punctatum. Samples were collected in the central Mediterranean Sea between 2010 and 2014. Plastics ingested belonged to small microplastics (0.2 - 2 mm), large microplastics (2 - 5 mm) and mesoplastics (5 - 25 mm), having mainly clear colors. Their frequency of occurrence in stomachs was equal to 2.7%, but it increases to 5.8% if only migratory species are considered. The higher number of plastics was found in E. risso and H. benoiti (5 in both species). The plastic ingestion may represent a risk for vertical migrant lanternfishes due to the increase in buoyancy. Ecotoxicological aspects linked to the potential effects of contaminants on lanternfish biology and to the transfer of pollutants throughout the marine trophic web up to top predators should be deepened.
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Nutrient pollution causes environmental damages on aquatic ecosystems worldwide. Eutrophication produces impacts in coastal ecosystems, affecting biota and ecosystem services. The Urias coastal lagoon (SE Gulf of California) is a sub-tropical estuary under several environmental pressures such as nutrient inputs from shrimp farm effluents and dredging related to port operations, which can release substances accumulated in sediments. We assessed the water quality impacts caused by these activities and results showed that i) nitrogen was the limiting nutrient, ii) shrimp farm effluents increased particulate organic matter and chlorophyll a in the receiving stations, and iii) dredging activities increased nitrite and reduced dissolved oxygen concentrations. The co-occurrence of the shrimp farm releases and dredging activities was likely the cause of a negative synergistic effect on water quality which mainly decreases dissolved oxygen and increases nitrite concentrations. Coastal zone management should avoid the co-occurrence of these, and likely others, stressors in coastal ecosystems.
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Artisanal fisheries in the estuarine systems of Mexico are poorly regulated due to fishery complexity and the lack of information on the biology of exploited species, their habitat and fishing methods. Due to these unknowns and to utilize existing catch data (i.e., landing date, catch and landing site, catch per species, and price), this chapter proposes the use of zones as management units to understand fishing processes by region, and to identify possible spatiotemporal changes of the marine communities along the coast of Sinaloa (SE Gulf of California). A total of 97 species, primarily teleost fishes (n = 80), composed the artisanal catch within 6 defined zones; the shrimp fishery was also important in all the zones. The importance of other fisheries differed according to zone, but in general, swimming crabs were most economically important in the North and demersal fishes were most important in the South. Three categories of target species were classified: high economic value and high abundance seasonal species; low abundance and high value resident species; and high abundance and low value resident species. Zonation will allow the identification of catch trends, which can be used for management; however, there still remains essential information that is needed for better management.
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The Goiana Estuary was studied regarding the seasonal and spatial variations of microplastics (o5 mm) and their quantification relative to the zooplankton. The total density (n 100 m�3) of microplastics represented half of the total fish larvae density and was comparable to fish eggs density. Soft, hard plastics, threads and paint chips were found in the samples (n¼216). Their origins are probably the river basin, the sea and fisheries (including the lobster fleet). In some occasions, the amount of microplastics surpassed that of Ichthyoplankton. The highest amount of microplastics was observed during the late rainy season, when the environment is under influence of the highest river flow, which induces the runoff of plastic fragments to the lower estuary. The density of microplastics in the water column will determine their bioavailability to planktivorous organisms, and then to larger predators, possibly promoting the transfer of microplastic between trophic levels. These findings are important for better informing researchers in future works and as basic information for managerial actions.
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Experiments were carried out with different Baltic Sea zooplankton taxa to scan their potential to ingest plastics. Mysid shrimps, copepods, cladocerans, rotifers, polychaete larvae and ciliates were exposed to 10 μm fluorescent polystyrene microspheres. These experiments showed ingestion of microspheres in all taxa studied. The highest percentage of individuals with ingested spheres was found in pelagic polychaete larvae, Marenzelleria spp. Experiments with the copepod Eurytemora affinis and the mysid shrimp Neomysis integer showed egestion of microspheres within 12 h. Food web transfer experiments were done by offering zooplankton labelled with ingested microspheres to mysid shrimps. Microscopy observations of mysid intestine showed the presence of zooplankton prey and microspheres after 3 h incubation. This study shows for the first time the potential of plastic microparticle transfer via planktonic organisms from one trophic level (mesozooplankton) to a higher level (macrozooplankton). The impacts of plastic transfer and possible accumulation in the food web need further investigations.
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Sediment transport across a foredune and beach at Ocean City, New Jersey, was examined to identify the effect of houses, dune topography, sand fences, vegetation, and wrack lines during an offshore wind. Houses are as close as 18 m from the crest of the 2- to 3-m-high foredune and are up to 9.0 m high and 12.8 m wide and spaced 4.0 to 5.0 in apart. Data were gathered during a 1-day study on 3 March 2003 with the use of 15 vertical sand traps, 13 erosion pins, and eight sets of anemometers placed 0.3, 0.6, and 0.9 in above the ground surface. Wind speeds 0.9 in above the ground ranged from 1.61 to 3.75 m/s. Trapping rates were negligible on the vegetated dune crest and up to 2.03 kg m(-1) h(-1) near mid foreshore. The highest rate of trapping was 2.4 kg m(-1) h(-1) at a < 10-m-wide unvegetated area in the dune. Houses shelter the dune from offshore winds and might contribute to dune stability. Increases in wind speed in the offshore direction cause greater rates of transport on the seaward side of the dune where vegetation has not had time to become established. Dune vegetation, remnant sand fences, wrack lines, and the sheltered area in the lee of the seaward dune ridge can trap sediment moving offshore during relatively low wind speeds. Sediment deposited at these obstacles could contribute to deflation of the backshore, which is the primary source of sediment moved to the intertidal foreshore. Losses of sediment from unvegetated portions of the dune to the beach can be overcome by replacing sand fences and suspending beach raking until the calmer summer months.
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Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22 th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3-5mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m(2) was observed. The highest abundances (>0.36 particles/m(2)) were observed in shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for zooplankton feeders.
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This review discusses the mechanisms of generation and potential impacts of microplastics in the ocean environment. Weathering degradation of plastics on the beaches results in their surface embrittlement and microcracking, yielding microparticles that are carried into water by wind or wave action. Unlike inorganic fines present in sea water, microplastics concentrate persistent organic pollutants (POPs) by partition. The relevant distribution coefficients for common POPs are several orders of magnitude in favour of the plastic medium. Consequently, the microparticles laden with high levels of POPs can be ingested by marine biota. Bioavailability and the efficiency of transfer of the ingested POPs across trophic levels are not known and the potential damage posed by these to the marine ecosystem has yet to be quantified and modelled. Given the increasing levels of plastic pollution of the oceans it is important to better understand the impact of microplastics in the ocean food web.
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Plastics constitute a large material group with a global annual production that has doubled in 15 years (245 million tonnes in 2008). Plastics are present everywhere in society and the environment, especially the marine environment, where large amounts of plastic waste accumulate. The knowledge of human and environmental hazards and risks from chemicals associated with the diversity of plastic products is very limited. Most chemicals used for producing plastic polymers are derived from non-renewable crude oil, and several are hazardous. These may be released during the production, use and disposal of the plastic product. In this study the environmental and health hazards of chemicals used in 55 thermoplastic and thermosetting polymers were identified and compiled. A hazard ranking model was developed for the hazard classes and categories in the EU classification and labelling (CLP) regulation which is based on the UN Globally Harmonized System. The polymers were ranked based on monomer hazard classifications, and initial assessments were made. The polymers that ranked as most hazardous are made of monomers classified as mutagenic and/or carcinogenic (category 1A or 1B). These belong to the polymer families of polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrenic copolymers. All have a large global annual production (1-37 million tonnes). A considerable number of polymers (31 out of 55) are made of monomers that belong to the two worst of the ranking model's five hazard levels, i.e. levels IV-V. The polymers that are made of level IV monomers and have a large global annual production (1-5 million tonnes) are phenol formaldehyde resins, unsaturated polyesters, polycarbonate, polymethyl methacrylate, and urea-formaldehyde resins. This study has identified hazardous substances used in polymer production for which the risks should be evaluated for decisions on the need for risk reduction measures, substitution, or even phase out.
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This review paper aims to present a practical, integrated procedure for the prediction of sediment transport rates in both the continental and marine environment, based on the settling velocity of particles. Such studies have important applications in diverse fields such as civil and coastal engineering, sedimentology and environmental geology, where they can assist in flood control and the prevention of contaminant dispersal by wind and water, as well as the siltation of dams and harbours. The formation of placer deposits including gold, diamonds and other heavy minerals is also controlled by sediment transport processes, so that these studies can form the basis for more efficient exploration programs. The first part of the paper discusses some basic principles important in sediment transport, followed by an overview of published methods to determine the settling velocity of differently shaped particles, including natural grains. The application of settling velocity to predict the entrainment threshold of sediments on plane, horizontal and inclined beds by unidirectional currents and oscillatory waves is then discussed, which finally leads to the determination of sediment transport rates over plane and rippled beds. The validity of this approach to natural conditions is tested against published field data where possible. Other, widely used methods are also critically discussed, pointing out severe problems in current sampling technology and the calculation of bedload transport in natural environments.
Managing artisanal fisheries in estuarine systems through the use of fishing zones in the South Eastern Gulf of California
  • M Ramírez-Rodríguez
  • F Amezcua
  • A Aguiar-Moreno
Ramírez-Rodríguez, M., Amezcua, F., Aguiar-Moreno, A., 2014. Managing artisanal fisheries in estuarine systems through the use of fishing zones in the South Eastern Gulf of California. In: Amezcua, F., Bellgraph, B. (Eds.), Fisheries Management of Mexican and Central American, Estuaries Estuaries of the World. Springer Netherlands, Dordrecht, pp. 113-121. https://doi.org/10.1007/978-94-017-8917-2.