Coastal Shrimp Research Articles

Detoxification mechanisms in shrimp: Comparative approach between hydrothermal vent fields and estuarine environments

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.

Seasonal variations in shrimp, nematopalaemon hastatus and bycatch compositions from coastal artisanal shrimp beam trawl fisheries off Lagos coast and management implications

Wet and dry season variations in shrimps and bycatch compositions were surveyed in the artisanal beam trawl shrimp fisheries operating in near shore water ( Keywords : Seasonal variations, bycatch, coastal, shrimp trawl, Nigeria AJAZEB Vol. 6 2004: pp. 1-5

Use of system dynamics modelling in design of an environmental restoration banking institution

This paper describes a system dynamics model developed to inform design of a proposed environmental restoration banking system. The purpose of the proposed system is to facilitate restoration of extensive areas of mangrove forests that have been cleared or damaged in large part by expansion of the commercial shrimp farming industry. A case study is developed for mangrove restoration in Thailand; however, the model is seen as applicable to a number of countries which have experienced severe mangrove loss. The scheme is based on environmental mitigation banking principles, in which users of an environmental resource are required to purchase from a mitigation bank credits representing restorations undertaken to compensate for environmental damage, thereby achieving “no net loss” of the environmental asset. The scheme proposed in this paper differs from usual mitigation banking practise in that the objective is to restore large degraded areas over and above present rates of consumption. Model simulations show that the restoration banking system may be effective in restoring coastal mangroves and in rehabilitating the coastal shrimp farming industry that is dependent on environmental services provided by the mangrove stock.

Adaptation to metal toxicity: a comparison of hydrothermal vent and coastal shrimps

AbstractRainbow vent field is one of the most metal‐contaminated hydrothermal sites on the Mid‐Atlantic Ridge near the Azores region. Two hydrothermal shrimp species dominate the fauna at the Rainbow site along with the mussel Bathymodiolus azoricus. Although the levels of essential and non‐essential metals in these shrimps have been studied, the biological consequences of a metal‐rich environment are still largely unknown. Therefore, the aim of this study was to determine the levels of metal‐binding proteins – metallothioneins (MT) and the activities of antioxidant enzymes – superoxide dismutase, catalase, total glutathione peroxidase and selenium‐dependent glutathione peroxidase in two hydrothermal vent shrimps (Mirocaris fortunata and Rimicaris exoculata) collected from the Rainbow site and to compare them with two coastal shrimps (Palaemon elegans and Palaemonetes varians) from a south Portugal lagoon (Ria Formosa) to evaluate their different adaptation strategies towards metals in their environment. Results show significant differences in MT levels and antioxidant enzymatic activities between vent and coastal shrimps and also between shrimp species collected from the same site. This suggests that biochemical responses in both vent and coastal shrimps are affected not only by the environmental characteristics but also by inter‐specific differences. Nevertheless, these responses apparently confer successful adaptation for survival in a metal‐extreme environment.

Internesting and Postnesting Movements and Foraging Habitats of Leatherback Sea Turtles (Dermochelys coriacea) Nesting in Florida

We tracked 10 leatherback turtles by satellite from 2 Florida Atlantic Coast nesting beaches for a period ranging from 38 days to more than 454 days. Movement and foraging areas were often coastal, which contrasts with other satellite telemetry studies where leatherbacks are more pelagic. Using kernel home-range estimation we identified the primary internesting residence areas as well as Atlantic foraging areas. The primary internesting habitat was centered east–southeast of Cape Canaveral, Florida, from 2 to 60 km offshore and extending 215 km along the coast. Atlantic foraging areas were located primarily on the continental shelf from 30° to 50°N, and in an offshore area centered at 42°N, 65°W, as well as off Africa in the Mauritania upwelling. Seasonally, the location of these foraging areas changed, occurring on the North American continental shelf from March through November and off the shelf from December through February. One of the tracked turtles may have been killed with 17 other leatherbacks by coastal shrimp fishing located near the Georgia–Florida border. We illustrate how using remotely sensed data could be used to prevent such mortalities.

Hierarchical population genetic structure in the commercially exploited shrimp Crangon crangon identified by AFLP analysis

The coastal shrimp Crangon crangon is an ecologically and commercially important species but there is limited knowledge of its genetic population structure. We utilised amplified fragment length polymorphisms (AFLPs) to investigate population differentiation among eight sampling locations comprising paired sites from north- and south-western Britain, the eastern English Channel and the Baltic Sea. Initial AMOVA and cluster analysis suggested strong differentiation, but outlier analysis identified three loci that might be subject to selection, one of which showed significant latitudinal variation in allele frequencies. Following exclusion of these outlier loci, and also of a divergent, genetically-impoverished sample from the UK Bristol Channel, cluster analysis revealed three major groupings, corresponding to geographical regions: western Britain, the eastern English Channel and the Baltic Sea. AMOVA identified significant differentiation both within and among these regions, with similar variation explained by each hierarchical level. C. crangon shows greater genetic structuring than has been found in many decapod crustaceans studied to date, and our results are consistent with unstable population sizes and gene flow restricted by distance and probably also hydrographic features. Further investigation of temporal stability in population structure is required, but broad-scale homogeneity of fishery stocks should not be assumed.

A conceptual framework for the sustainability assessment procedures of the shrimp aquaculture industry in coastal Bangladesh

Shrimp aquaculture is now establishing itself as an important aquaculture industry in coastal Bangladesh. However, the benefit of this industry is concentrated to only the interests of a specific group of people who contribute a significant amount of foreign earnings to the nation, while the present development process is posing a challenge to the coastal sustainability, as well as the industry itself. This paper analyses the contexts of sustainability in relation to the coastal shrimp aquaculture industry and identifies the relevant sustainable factors or indicators for coastal Bangladesh. In addition, this paper examines these sustainability indicators quantitatively in regard to how they can be used through a unifying index that allows the present shrimp aquaculture to be assessed considering all sustainability components, such as environmental, economic and socio-cultural factors separately and in interaction with each other. Finally, this paper presents a conceptual framework for a sustainability assessment methodology of coastal shrimp aquaculture in Bangladesh.

Characterization of water quality in shrimp ponds of different sizes and with different management regimes using multivariate statistical analysis

Coastal shrimp aquaculture in Bangladesh is mostly practiced in an agricultural unit called a Gher, which is a special type of agricultural field with elevated surrounding embankments/borders situated by the side of a river that is used to grow rice in winter and shrimp in summer. Ghers of different sizes are managed in different ways. An on-farm project was carried out to study the effects of Gher size and their related management practices on water quality, shrimp production and the economic returns of shrimp farming in the Southwest coastal region of Bangladesh. We present here the results of this project with respect to water quality as explored through factor analysis, which was applied as a way to understand the nature and extent of the effects of different variables. For the majority of the variables and factors, one-half to two-thirds of their variability was explained by changes over time (months), and a further one-quarter to one-third was explained by Gher size and associated management practices. The alternating dry/monsoon season and water management practices determined long-term and large-scale (annual) water exchange in the Ghers that mainly affected processes related to live and dead particles suspended in the water column. Processes related to decomposition and nitrification were more dependent on short-term (days) water circulation in the Ghers, which is turn was reliant on the time span between the exchanges of water in the Ghers and river. Our results show that improved management leads to higher natural and shrimp productivity in the smaller Ghers and strongly support the argument put forward by the policy makers and scientific community in Bangladesh that the smaller the Gher, the better they can be managed and the better the possibility of increased shrimp survival and production.

Diet and feeding of the cutlassfish trichiurus lepturus in the subtropical convergence ecosystem of southern brazil

the diet and feeding of the cutlassfish trichiurus lepturus were studied based on analyses of the stomach contents of larvae, juveniles, and adults collected along the continental shelf and shelf break off southern brazil, from the cape of santa marta grande (28°36′s) to chuí (34°45′s). the larvae and pre-juveniles with a total length of <5 cm were found to have fed almost exclusively on calanoid copepods, whereas juveniles (5 to 30 cm) fed on small zooplanktonic crustaceans such as lucifer faxoni and promysys atlantica. on the other hand, sub-adults (30 to 70 cm), fed on euphausiids, mainly euphausia similis, and small fish, mostly anchovy engraulis anchoita. adults (70 to 160 cm) fed on a wide range of larger prey, such as anchovy, sciaenid fish, cephalopods and coastal shrimps, as well as euphausiids. the juveniles and sub-adults fed more intensively than adults during the warm-water season whereas adults fed more intensively during the cold-water season. feeding activity was more intense at night, while cannibalism was more frequent during the warm season, when biological productivity was lower. finally, diet diversity was higher in coastal waters, during the warm season. the abundance of cutlassfish off southern brazil may be explained by the fact that it is adapted to feed on a wide size-range of both pelagic and demersal prey.

Production and economic return of shrimp aquaculture in coastal ponds of different sizes and with different management regimes

Coastal shrimp (Penaeus monodon) aquaculture in Bangladesh is mostly practiced in a special type of field/pond situated by the side of a river -- called a Gher -- that is used to cultivate rice in winter and shrimp in summer. Ghers of different sizes are managed in different ways. In order to understand the effects of Gher size and their corresponding management practices on the production and economic returns of shrimp farming, we conducted an on-farm study in three small (1–5 ha), three medium (6–10 ha) and three large (>10 ha) Ghers located in the coastal Southwest region of Bangladesh. The mean harvest weight of shrimp was similar in all Ghers, but survival rates were higher in the small (50%) and medium (37%) ones than in the large (18%) ones. The high mortality in the large units led to a production that was lower than one-half of that in the small Ghers (about 80 and 200 kg/ha, respectively). The total variable costs per unit area were similar in all Ghers, but the importance of different items varied with Gher size. In the small Ghers, there are relatively high investments on inputs and labor. This expenditure results in lower shrimp mortality and higher production, which in turn results in gross returns that are larger than the total costs -- hence, a positive and high net return. In large Ghers, the fixed costs are larger than in the small ones simply because of the size of the pond. Variable costs include higher investments in post-larvae and labor than in small Ghers, and lower inputs applied only at pond preparation. This results in higher shrimp mortality and lower production, which in turn results in gross returns that are smaller than the total costs -- hence, a negative or low net return. These findings have positive implications for the future policy formulation of coastal shrimp aquaculture in Bangladesh.

Coastal Shrimp Aquaculture Systems in Southwestern Bangladesh

Coastal Shrimp Aquaculture Systems in Southwestern Bangladesh

Perspectives of the coastal and marine fisheries of the Bay of Bengal, Bangladesh

Bangladesh has vast coastal and marine resources along its south edge. Due to the geographical position and climatic condition, the coastal area of the country is known as one of the highly productive areas of the world. Bangladesh is rich not only in terms of its vast water areas but also in terms of the biological diversity. One of the unique features of the coastal areas is the influence of the mangrove forests, which support a high number of fishes and other commercially important aquatic organisms. The biological and ecological values of the Bay of Bengal have been pointed out by many authors. The coastal and marine fisheries have been playing considerable roles not only in the social and economic development of the country but also in the regional ecological balance. A large number of commercially important fishes have long been exploited which are of high export values. Shrimp aquaculture has become a highly traded export-oriented industry for the last few decades. In spite of having bright prospects, marine aquaculture on a commercial basis as well as marine stock enhancement and sea ranching are yet to be developed. The marine fisheries sector has been suffering from chronic disintegration and mismanagement that have led to many consequences. Most of the commercially important fish stocks are either overexploited or under threat. Marine pollution has reached a level that could create an unmanageable situation in the near future; coastal shrimp farming has generated considerable debates due to its adverse environmental and socioeconomic impacts. The Bay of Bengal and its coastal areas are one of the most poorly studied areas of the world although it possesses high potential for further stock improvement. Proper attention is needed in every aspect of exploitation, handling and processing, export and marketing as well as in biological and institutional management strategies. The Bay of Bengal has been increasingly important for local development as well as for a global perspective. The coastal and marine fisheries of the Bay of Bengal are briefly reviewed in this paper to provide a salient feature of the available information and resource base and to identify future research and management needs.

Technology, Knowledge Systems, Population Dynamics, and Coastal Ecosystems

The three following papers describe a range of complex relationships among coastal ecosystems, demographic patterns, and the effects of technology on coastal resource use. All three deal with the production of living aquatic resources, whether from natural systems or from culture, and therefore offer some interesting comparative insights since the coastal industry sector, i.e., seafood production, is "controlled." None of the cases demonstrate a direct linkage between population pressure and negative environmental effects, although all show lesser or greater degrees of sustainability in resource use. On a spectrum from coastal ecosystems least influenced by recent technology developments to those most altered by their adoption, the coastal canoe fisheries of Ghana represent the least influenced (1). The next most affected, namely by the use of compressors for diving and better boats, is the Galapagos and Ecuador mainland sea cucumber fishery (2). The third case is coastal shrimp farming in Vietnam and Thailand, in which the coastal ecosystems have been much transformed by technology, especially in Thailand (3). The reader can also refer to additional material on the situation in Thailand in the paper by Barbier and Cox (4). Each case is famous in its own right, but not until publication of this special issue of Ambio have they been described so comprehensively with their human population, economic, and resource elements studied together. To some extent, the papers here explode some of the public myths surrounding the cases. The Ghana fishery is well known among fisheries scientists, and to some extent among fisheries anthropologists, for the influence of the dynamic West African "upwelling" fisheries, on fishing people's migrations. The Galapagos and Ecuador mainland sea cucumber fishery and the southeast Asian shrimp-farming developments have become celebrated coastal issues, brought to global media attention by international and local nongovernment organizations focusing on their environmental and social welfare effects.

Assurance bonds: A tool for managing environmental costs in aquaculture

The environmental costs associated with coastal aquaculture, though poorly understood, can in some cases be quite large. The presence of risk, uncertainty and insufficient monitoring can greatly reduce the power of traditional economic instruments such as environmental taxes and tradable permit systems to internalize these costs. Using the Texas shrimp farming industry as a specific example, this article explores the potential of environmental assurance bonds (EABs) as an alternative economic instrument to internalize environmental costs of aquaculture production under such conditions. Drawing from previous literature, an explicit distinction is made between two mechanisms simultaneously incorporated in the EAB: a deposit‐refund incentive and social insurance. The article discusses the role of each of these mechanisms in shifting the environmental costs of production back to firm. Practical application of EABs in the Texas coastal shrimp farming industry is then examined.

The dinoflagellate genus Prorocentrum along the coasts of the Mexican Pacific.

We surveyed the dinoflagellate genus Prorocentrum Ehrenberg in Mexican Pacific waters, where it is rather common and sometimes causes red tides in coastal areas or shrimp farms. Material collected from Baja California and the Gulf of California was analyzed. Thirteen species were identified, all of them planktonic (although P. mexicanum is also epiphytic). All species are described by light microscopy, and most are also described by scanning electron microscopy; comments on morphology, taxonomy and distribution are made. Red tides were caused by P. dentatum, P. minimum and P. triestinum. Prorocentrum mexicanum and P. minimum were suspected of being toxic. Four species, previously reported in the Gulf of California, were not found. A total of 18 species, including the new records P. dactylum and P. lebourae have been to date reported from the Mexican Pacific.

Results of an Experimental Shrimp Fishery in Chaleur Bay, Southern Gulf of St. Lawrence

Abstract Five surveys of coastal shrimp abundance and distribution were conducted aboard a commercial shrimp trawler between 25 Aug and 4 Nov 1997 to evaluate the potential for a commercial shrimp fishery in Chaleur Bay, southern Gulf of St. Lawrence. The net was equipped with a fish exclusion grate (25-mm bar spacing) to reduce fish bycatch. The initial target species was sevenspine bay shrimp Crangon Sepemspinosa, but very few were captured in the depths fished (20–82 m). The principal shrimp species captured were Aesop shrimp Pandalus montagui and Arctic argid Argis dentata. The catch rates of shrimp were too low to support a commercial shrimp fishery in Chaleur Bay. Average catch rates for Aesop shrimp ranged between 0.5 and 3.2 kg/h (whole animals, wet weight), and catch rates for Arctic argid ranged between 0.5 and 9.3 kg/h. Bycatch of fish was low (usually <10 kg/h) from late Aug to Oct but were excessive during early Nov when an average of 102 kg/h of Atlantic herring Clupea harengus and rainbow s...

G. Smaldon, L.B. Holthuis, C.H.J.M. Fransen Coastal shrimps and prawns. Keys and notes for identification of the species. 2nd edition, vii, 142p. Shrewsbury: Field Studies Council, 1993. (Synopses of the British Fauna, New Series, 15.) Price £16.50.

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G. Smaldon, L.B. Holthuis, C.H.J.M. Fransen Coastal shrimps and prawns. Keys and notes for identification of the species. 2nd edition, vii, 142p. Shrewsbury: Field Studies Council, 1993. (Synopses of the British Fauna, New Series, 15.) Price £16.50.

G. Smaldon, L.B. Holthuis, C.H.J.M. Fransen Coastal shrimps and prawns. Keys and notes for identification of the species. 2nd edition, vii, 142p. Shrewsbury: Field Studies Council, 1993. (Synopses of the British Fauna, New Series, 15.) Price £16.50.

Remote sensing application to study the coastal shrimp farming area in Bangladesh

Abstract Data from black and white aerial photographs (1974–75), Infrared colour (IRC) aerial photographs (1983–84), Landsat Multispectral Scanner (MSS) of 1984 and Landsat Thematic Mapper (TM) of 1987–88 are used to locate and measure the existing coastal shrimp fanning areas of selected sites and finally to find out the sequential changes in time perspective in order to explain spatial changes for better planning and scientific management. The shrimp farming and mangrove forest areas are identified and located by remote sensing techniques. The Landsat (MSS & TM) data are used to delineate the surface feature of the coastal area. Infrared colour (IRC) aerial photographs provided most revealing information. Sequential aerial photographs provided information on change in time and places. This study reveals that the shrimp farming areas are expanding through destruction of the mangrove forest of Chokoria Sundarban and agricultural land of Rampai and Paikgachha area. For scientific development of the coastal...

Reduction of fish by-catch in shrimp trawl using a rigid separator grid in the aft belly

Abstract In 1989 and 1990, a new concept to avoid the by-catch of fish in a shrimp trawl was developed in Norway. The system consists of a rectangular aluminium grid with longitudinal bars. The grid is installed in the extension piece, just in front of the codend, angled 48°, with a fish outlet on the top. In front of the grid a guiding funnel or flapper is mounted. Investigations into different grid sizes, bar distances, size of fish outlets, and guiding funnel or flapper constructions during practical tests, have led to several recommended measures. Smaller coastal shrimpers should use grids at least 0.7 m wide and 1.40 m long, while the bigger offshore trawlers should use a 1.0 m wide and 1.5 m long grid, both with a recommended bar separation of 19 mm, which gives an acceptable shrimp loss below 5%. RCTV-observations of the sorting grid system during fishing have shown that most of the shrimps (Pandalus borealis) passed in a straight line through the grid, while fish were guided upwards towards the fish outlet, either by swimming in front of the grid, or sliding along the bars. Some of the smaller fish passed through the grid and ended up in the codend. A combined speed and angle sensor, mounted just behind the grid, measured the horizontal speed of water through the grid to be 0.7 of the towing speed, and the angle of the grid to be 3–5° less than the theoretical mounting angle of 48°. The separator grid allowed an increasing escape of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) up to a length of 20 cm, whereby all fish escaped. The 100% escape lengths for redfish (Sebates sp.), long rough dab (Hippoglossoides platessoides), and polar cod (Boreogadus saida) were 18, 24 and 24 cm, respectively. The Greenland halibut (Reinhardtius hippoglossoides) gave a rather high 100% escape length of 30–32 cm, probably due to the behaviour of this flatfish which swims on its side. The handling of the separator system has so far caused only minor problems, and the pre-sorting of fish by the separator grid results in less sorting work on deck. The separator grid was made compulsory in the northern coastal shrimp fishery from 1 March 1990, from 1 January 1992 in the offshore fisheries and will be compulsory in the Barents Sea and Spitsbergen waters from 1 January 1993.