Brackish Water Shrimp Research Articles

A field survey of chemicals and biological products used in shrimp farming

This study documented the use of chemicals and biological products in marine and brackish water shrimp farming in Thailand, the world’s top producer of farmed shrimp. Interviews were conducted with 76 shrimp farmers in three major shrimp producing regions, the eastern Gulf coast, the southern Gulf coast and the Andaman coast area. Farmers in the study used on average 13 different chemicals and biological products. The most commonly used products were soil and water treatment products, pesticides and disinfectants. Farmers in the southern Gulf coast area used a larger number of products than farmers in the other two areas. In the study, the use of more than 290 different chemicals and biological products was documented. Many of the pesticides, disinfectants and antibiotics used by the farmers could have negative effects on the cultured shrimps, cause a risk for food safety, occupational health, and/or have negative effects on adjacent ecosystems. Manufacturers and retailers of the products often neglected to provide farmers with necessary information regarding active ingredient and relevant instructions for safe and efficient use.

Effect of Delayed Icing on the Quality Changes in Brackish water Shrimp Penaeus monodon During Ice Storage

Effect of Delayed Icing on the Quality Changes in Brackish water Shrimp Penaeus monodon During Ice Storage

EFFECT OF LONG TERM BRACKISH WATER SUBMERGENCE OF AGRICULTURAL LAND IN SHRIMP CULTIVATION

A long term (1990-2000) soil and water salinity monitoring programme was undertaken to address the salinization problem in paddy cum brackish water shrimp cultivation area . The information generated during this period has been presented in this paper. In monsoon season, particularly from August to October soil salinity had increased from 1.4 dS/m to 10.3 dS/m. In between November and February depth of ground water table remained within 0.12 m to 0.33 m and rest of the year it remained at or close to the surface. So, due to presence of ground water table at shallow depth and slower permeability downward movement of soluble salts from the top is very limited. Under Pashur river system average submerged water salinity was found to be 13.8 dS/m to 17.5 dS/m in between March and- May. In Shibsha river system it was found to be 13.2 dS/m to 24.2 dS/m in between February and June. More soluble salts have been accumulated in the topsoil over long period brackish water shrimp cultivation. Increasing tendency of soil pH from 7.5 to 8.2 may be due to high amount of cations like Ca, Mg, and K. High amount of S may be one of the possible reasons for P deficiency in brackish water submerged condition. Soils are rich in B. Cu, Fe except Zn. Late transplantation, without or very little fertilization, without insecticides, use of aged seedlings, wider spacing, relatively high flooding at the time of aman transplantation, minimum tillage and little opportunity of flushing and leaching of fresh water are the common constraints of paddy cultivation in paddy cum brackish water shrimp cultivation area.

Environmental issues in brackish water shrimp aquaculture in Sri Lanka.

Shrimp exports are one of Sri Lanka's major foreign exchange earners and account for 40%-50% of total aquaculture exports. There has been a recent and rapid expansion of the industry in the Northwestern Province (NWP) of Sri Lanka but the industry has suffered from disease outbreaks and environmental problems. Currently, shrimp farms cover nearly 3000 ha of the coastal area of the NWP. The environmental impacts of shrimp cultivation in general are well known and numerous research studies have been done. However, little work has been carried out in Sri Lanka. This study provides some necessary background to brackish water shrimp aquaculture in Sri Lanka. It focuses briefly on the development of shrimp aquaculture and the current status of the industry. Emphasis is placed on two broader aspects--impacts on the existing wetland ecosystem and on the environment. These impacts are presumed to be the main causes hindering the growth of the industry and raising widespread public protest. Current ecosystem and environmental management practices are discussed. Finally, strategic issues for management and sustainable growth are discussed.

Hydrology of inland brackishwater shrimp ponds in Chachoengsao, Thailand

This study focuses on a new trend in shrimp aquaculture, the development of brackishwater ponds for Penaeus monodon culture in inland freshwater areas of Thailand’s Central Plain. Water balances were calculated for ponds and reservoirs at an inland shrimp farm in Chachoengsao, Thailand, between May and July 1999. Regulated inflow and outflow were the largest water fluxes, averaging 0.94 and 0.70 cm/day. Other daily average water gains were rainfall (0.52 cm/day) and runoff (1.7 cm/day), and other water losses were evaporation (0.31 cm/day) and seepage (0.52 cm/day). Over an entire crop cycle, of average length 109 days, average water inputs were: initial pond filling (84 cm); regulated inflow (103 cm); rainfall (57 cm); and runoff (3 cm). Average outputs were: regulated outflow (76 cm); seepage (57 cm); evaporation (34 cm); and draining at harvest (87 cm). The main feature of note in the water balance is the large volume of regulated outflow. All regulated outflow and most (82%) of the pondwater drained at harvest went directly to the irrigation canal system. Such large volumes of discharge could have serious environmental implications because small inland waterways have low assimilative capacity and pond effluent is saline. Consumptive water use for 14 inland shrimp ponds and reservoirs averaged 0.83±0.14 cm/day. Consumptive water use was also measured for 11 nearby rice fields, the main land use in the regions where inland shrimp farming is proliferating. Rice paddy water use averaged 0.91±0.17 cm/day. There was no significant difference in the daily consumptive water use of shrimp ponds and rice fields, suggesting that conversion from rice farming to shrimp farming would have little net impact on water availability for irrigation.

BRACKISH WATER SHRIMP CULTIVATION RESTRICT THE COASTAL AGRICULTURE

Impact of brackish water shrimp culture on agriculture was studied in the Rampal Thana of Bagerhat district. Evidences for serious land degradation were obtained through surveys on the land use patterns, areas of land available for agriculture and level of production in various field crops covering a period of about two decades since 1975 when shrimp cult ure began in the area. The progressive accumulation of salt in the soil threatens permanent loss of soil fertility and has restricted the crop production in the area. The negative impacts of brackish water shrimp cultivation in the area is substantial in totality. Shrimp cultivation needs proper legal framework for providing check on furthering deterioration.

Biological Origins of Off-flavours in Fish and Crustaceans

Edible fish and crustaceans, either of salt or of freshwater origin, are occasionally affected by off-flavours that can be related to the animal's diet or the natural environment in which they live. Off-flavours include petroleum and blackberry-like flavours in salmon and cod; garlic-like flavours in prawns and sand-lobsters; iodoform-like flavours in prawns, shrimp and fish; and muddy and earthy flavours in brackish-water fish and shrimp. Knowing the source of such off-flavours will in some cases assist processors in taking remedial action. This paper will discuss the possible biochemical pathways to five of these off-flavour compounds and, in addition, will provide evidence as to the likely marine organisms responsible for their formation. Methods to reduce the severity of such off-flavour incidents will also be described.

Biological origins of off-flavours in fish and crustaceans

Edible fish and crustaceans, either of salt or of freshwater origin, are occasionally affected by off-flavours that can be related to the animal's diet or the natural environment in which they live. Off-flavours include petroleum and blackberry-like flavours in salmon and cod; garlic-like flavours in prawns and sand-lobsters; iodoform-like flavours in prawns, shrimp and fish; and muddy and earthy flavours in brackish-water fish and shrimp. Knowing the source of such off-flavours will in some cases assist processors in taking remedial action. This paper will discuss the possible biochemical pathways to five of these off-flavour compounds and, in addition, will provide evidence as to the likely marine organisms responsible for their formation. Methods to reduce the severity of such off-flavour incidents will also be described.

A multiperiod programming evaluation of brackishwater shrimp aquaculture development in Indonesia 1989/1990–1998/1999

Brackishwater shrimp aquaculture was economically evaluated to determine the best mix of aquaculture enterprises in Indonesia. Data were compiled for three categories of brackishwater shrimp aquaculture systems: Extensive, semi-intensive, and intensive, as well as for different farm sizes, small-scale (2 ha), medium-scale (5 ha), large-scale (10 ha) and extra large-scale (30 ha). These data were used to simulate the enterprise combination for the shrimp-producing regions in Indonesia. Model results showed that small-scale and medium-scale semi-intensive systems were the best strategies for shrimp aquaculture development in Indonesia. Extensive systems entered in solution only if there were skilled labor constraints. Risk analysis revealed risk-expected net present income trade-offs and declining risk with declining expected net present income for all regions.

Observations and model predictions of daily areal primary production in a eutrophic brackish water culture pond

Observations of daily gross primary production of oxygen per unit area in a eutrophic, brackish water shrimp culture pond over a 14-day period are compared with predictions from two models in order to assess the utility of the model approaches for ponds and to refine observational protocols and techniques for pond assessment. The models predicted rates (3.2 to 37.7 g O 2 m −2 d −1) which exceeded observations (4.7 to 15.7 g O 2 m −2 d −1) at all but the lowest light levels. Observed rates were also lower than other observations at similar light levels. These shortfalls are attributed to (1) the inadequacy of the method for estimation of community respiration as a component of gross production, in the absence of direct observation; and (2) the possibility of nutrient limitation of rates in the pond ecosystem. The models are sufficiently sensitive to chosen parameter values, and the day-to-day variation of the parameters in the ecosystem likely sufficiently variable, that daily determinations of parameters should be made when possible, with particular attention to timing and use of surface water. Field observations of daytime community respiration, and improved knowledge of its controlling factors and relationships, are important needs for the advancement of model treatment of photosynthesis in ponds. Eutrophic pond ecosystems have characteristics (vertical temperature structure resembling natural water bodies, complete light extinction within the shallow water column) which make them amenable to study as microcosms of some general aspects of aquatic primary production, particularly problems involving the prediction of daily areal rates from small-scale volume-based rate data.

The effects of zeolites and other alumino-silicate clays on water quality at various salinities

Intensive marine and brackishwater shrimp farms commonly use large quantities of zeolites in ponds with the aim of removing ammonia through ion exchange, providing physical cover over sediments to prevent leaching of metabolites into the water column, removing suspended solids, and improving water colour and diatom blooms. Zeolites have the capacity to remove ammonia and other nutrients/ metabolites from fresh waters by ion exchange and absorption. However, there are doubts as to their efficacy and cost-effectiveness in saline waters. This research was conducted to investigate the effect of zeolites on water quality under a range of conditions in seven laboratory-based trials and one pond trial. These investigated the effects of six types of commercially available zeolites and three other alumino-silicate clays at levels from one to 26 times the recommended dose rate (380 kg ha-1 month-1) in water at salinities of 0-30%o for periods of 3-19 days. The results indicated that none of the zeolites or natural alumino-silicate clays from Thailand had any significant effects on the removal of nutrients from water at salinities of 0-30%. Neither were these able to prevent nutrient emission from shrimp pond sediments in water at 20-2l%o salinity. Furthermore, none of the other suggested functions of reducing levels of particulate nutrients, enhancing algal biomass, or affecting oxygen and pH dynamics were evident. This study could not establish any useful, cost-effective role for zeolites in shrimp pond culture.

Chemical Characteristics of Bottom Soils from Freshwater and Brackishwater Aquaculture Ponds

AbstractSoil chemical analyses were conducted on samples from 358 freshwater fish ponds and 346 brackishwater shrimp ponds. Freshwater ponds were located in Honduras, Rwanda, Bhutan, and the United States. Ponds in the United States were in Alabama, Georgia, Mississippi, Florida, and South Carolina. Brackishwater ponds were in Thailand, Ecuador, Philippines, and Venezuela. Soils of freshwater and brackishwater ponds did not differ greatly in average concentrations and concentration ranges for carbon, nitrogen, calcium, and pH. Concentrations of copper and barium tended to be higher in freshwater soils than in brackishwater ones. All other measured chemical constitutents tended to be more abundant in the soils of brackishwater ponds than in those of freshwater ponds. For the most part, ranges of pond soil chemical properties were similar to those of terrestrial soils, with freshwater pond soils resembling terrestrial soils from humid areas and brackishwater soils being similar in many respects to soils of arid regions. However, some brackishwater pond soils were highly acidic, acid‐sulfate soils. Data were arranged into concentration categories (very low, low, medium, high, and very high) to facilitate comparisons of the present data set with other data on soil chemical properties for aquaculture ponds. All ponds included in the present study were used for aquaculture, showing that it is possible to rear fish and shrimp across an extremely wide range of soil chemical properties.

Liming and Fertilization of Brackishwater Shrimp Ponds

Agricultural limestone and burnt lime are applied either to the water during shrimp production or to pond bottoms between shrimp crops. However, unless the total alkalinity and total hardness of pond water is below 50 mg/L as equivalent CaC03 or the pond soils are acidic (pH < 7), liming is of little or no value. The use of burnt lime should be avoided because this material can cause high pH in water and soil. Chemical fertilizers or manures are used to fertilize brackishwater ponds. Fertilization programs for brackishwater ponds usually require more nitrogen (N) than those for freshwater ponds. Phosphorus (P) fertilization is important both in brackishwater and freshwater ponds. Because water is exchanged often in brackishwater ponds, fertilizer should be applied in small doses and at frequent intervals. Most managers of brackishwater ponds prefer a large proportion of diatoms in the phytoplankton community. An N:P application ratio of 20:l in ponds favors diatoms; in fiberglass tanks with water of low s...

Aquaculture and coastal zone management in Bangladesh

Abstract This article gives a brief survey of the present status of brackish water shrimp culture and its increased importance in the economy of Bangladesh. The high and increasing population density is forcing people to engage in agriculture and aquaculture in low lying coastal areas where they are exposed to cyclones and tidal floods. Colonization of these areas has, however, led to deforestation and other adverse effects on the ecosystem. A policy of intensive farming using the most modern methods is necessary to reduce these effects caused largely by extensive low yield practices in a country where available land is extremely limited. It is proposed that the government augment its present policy of reforestation and take other steps to conserve the environment and to reduce siltation and erosion. Whereas the construction of coastal embankments to protect human life and property is necessary, much greater efforts should be taken to realize these engineering projects with minimum damage to the environment. A proper coastal zone management policy requires increased coordination among the numerous governmental agencies and the collection of sufficient reliable data on the ecosystem.

Variation in sex determination in natural populations of a shrimp

AbstractStrategies of sex determination were studied in Gammarus duebeni, a brackish water shrimp (Crustacea, Amphipoda). Animals from Budle Bay, northern England, have environmental sex determination (e. s. d.), in accord with a population studied in Germany. Males are produced in long day photoperiods and females in short days. By contrast, animals from southern England show no significant sex ratio variation with daylength. This is the first report of such variation in sex determination for an invertebrate. Detailed studies of Budle Bay animals show that sex is determined several weeks after young are released by the mother; that the critical daylength is longer at Budle Bay than in Germany; and that the critical response is cued at the onset of a photophase. The nature of sex determination in G. duebeni may be associated with population dynamics. Males gain greater relative fitness by large size than females. E. s. d. is then adaptive where the breeding season produces significant growth differences between early and late animals, but where generations do not overlap. Comparisons are drawn with the flexible sex determining system in Menidia menidia (Pisces).

Effects of water depth and artificial mixing on dynamics of Philippines brackishwater shrimp ponds

The effects of pond water depth (0·5, 1·0 and 1·5 m) and artificial circulation (with/without) on certain pond dynamic processes were evaluated in a factorial design. Deep ponds had more uniform temperatures, with less rapid temperature changes, greater whole pond respiration, and greater temperature and oxygen stratification. Artificial circulation reduced thermal and oxygen stratification. Sediment respiration, which was estimated using a new technique, was more than three times greater than plankton and shrimp respiration combined, regardless of treatment combination. Shrimp yields were not significantly different for any of the six treatment combinations.

Behaviour, tolerance and anaerobic metabolism under hypoxia in the brackish-water shrimp Crangon crangon

Behaviour, tolerance and anaerobic metabolism under hypoxia in the brackish-water shrimp Crangon crangon

Influence of steady-state and fluctuating salinities on the oxygen consumption and activity of some brackish water shrimps and fishes

Oxygen consumption, locomotory activity and, in some cases, osmoregulatory responses of different populations of Palaemon adspersus (Rathke) and Pomatoschistus microps (Krøyer) from the Isefjord ( S 19‰) and Karrebaek Fjord ( S 12‰) in Denmark and the Barther Bodden ( S 6‰) in the G.D.R. to short-term salinity fluctuations, and after long-term adaptation, were tested. The same tests were performed on populations of Gasterosteus aculeatus (L.), Palaemonetes varions (Leach) (both from Barther Bodden, G.D.R.) and Palaemon elegans (Rathke) (Black Sea, Bulgaria, S 18‰). The steady-state experiments showed that the standard metabolic rates of P. adspersus and Pomatoschistus microps reach their lowest levels at mean biotope salinities at both 10 and 20°C. In contrast, the routine metabolic rates of both species are independent of salinity in the ecological salinity range. All Palaemon adspersus and Pomatoschistus microps populations responded to sudden changes in salinity with increased locomotory activity and respiration regardless of the direction of stressing. Metabolic adaptation in these euryhaline species, which is not synchronous with osmotic readjustment, takes from 5 to 12 h, depending on the salinity gradient. The polystenohaline Palaemon elegans from the Black Sea and the holeuryhaline Palaemonetes varians from the Barther Bodden exhibit similar short adaptation times (≈ 2 h) to identical salinity gradients but in different salinity zones.

The influence of hypoxia on the blood regulation of the brackish water shrimp Palaemonetes varians Leach

During periods of hypoxia in hypotonic media, Palaemonetes varians Leach showed an unimpaired regulation of blood chloride until some minutes before death. Heart rate showed no clear dependence on the water oxygen tension (P wO 2) and postbranchial haemolymph oxygen tensions slowly decreased during progressive hypopoxia from a normoxic level of ≈ 30 mm Hg until the animals turned opaque some minutes before they died. Blood pH increased in hypoxia, from 7.6 in normoxia to > 8 in P wO 2 10 mm Hg. Taken together, these data have been taken to indicate that the oxygen consumption rate at the critical point (MO 2 P cr) of this species is very low (P wO 2 = < 10 mm Hg) compared with other brackish water natantians studied. The ecological significance of this to the species is considered.

The influence of temperature on the osmoregulation of the brackish-water shrimpPalaemonetes variansLeach

Abstract Palaemonetes varians Leach from a brackish-water Danish fjord have been shown to be salinity tolerant over at least the range 1–35 ‰ S at 20°C but this tolerance range was narrowed to 10–30 ‰ S at 2 °C. Blood osmolarity was regulated optimally at around 20 °C which corresponds approximately to the mean diel summer temperatures at the place of capture and is a high value compared with values published for other brackish-water natantian species. In hypotonic media blood Cl− regulation is less strong at low than at high temperatures. It is considered that the species is very well adapted to live in the less saline areas of the fjord which are also subject to high water temperatures in summer. In such areas only, is P. varians able to compete successfully with Palaemon adspersus.