Native Shrimp Research Articles

Utilisation de la méthode capture-marquage-recapture pour une évaluation quantitative des populations de mollusques dans deux sites à Lampsar (Vallée du Fleuve Sénégal)

The authors have made an estimate of the number of mollusc by the capture-mark-recapture method at two sites in the Valley of the Senegal River. This quantification is necessary to track the effect of the introduction in one of the sites of a native shrimp Machrobrachium vollenhovenii, predator of mollusc. The populations of two study sites were approximately 1,800 and 1,500 individuals with coefficients of variation of about 30%.

Finely tuned response of native prey to an invasive predator in a freshwater system

Lack of shared evolutionary history reduces the expectation that native prey will detect and respond to invasive predators. Four mechanisms may explain the adaptive response that is nevertheless seen in various systems: prey may perceive the invasive predator through cue similarity with preexisting predators, cues of conspecifics eaten by the invasive predator, a learned response based on experience with the invasive predator (e.g., cue association), and cues from the invasive predator that are specific to it. We performed laboratory experiments in which zooplankton (Daphnia mendotae) responded adaptively to the zooplanktivore Bythotrephes longimanus (migrating downward), showed no response to taxonomically similar predatory cladocerans, and responded adaptively to more taxonomically distant native fish (migrating downward) and native shrimp (migrating upward). Conspecific cues associated with Bythotrephes predation actually reduced the response of D. mendotae to Bythotrephes. Combined with previous experiments that rule out learning, our experiments rule out the first three mechanisms above, demonstrating that D. mendotae respond to cues specific to and produced directly by Bythotrephes. This finely tuned response may be retained from an ancestral species that coevolved with Bythotrephes in its native range, or may have rapidly evolved due to strong selection by the invasive predator.

Rate (ROI) and severity (SOI) of infection of white spot disease in cultured and captured Penaeid shrimps in the Persian Gulf using histopathology and polymerase chain reaction.

White Spot Disease (WSD) is well known as a widespread viral disease in shrimps from 1992. Many studies focused on morphological, histopathological and epidemiological characteristic and pathogenecity of the disease but less on the determination of the severity of WSD using the histopathological features in target tissues. A generalized scheme for assigning a numerical qualitative value to severity grade of infection considering to histopathology and counting the inclusion bodies in different level of infection and different microscopic fielding immersion lens was accomplished before. This study was conducted in order to estimate the rate of infection (ROI) and the severity of infection (SOI) of WSD in native shrimps in the Persian Gulf. About 90 live specimens of affected cultured Penaeus indicus were collected from Abadan region, south Iran and 150 specimens of native shrimps were captured from the Persian Gulf. Histopathological changes were observed by light microscope in target organs such as: gills, cuticular epidermis, heart, hemolymph, fore stomach and hepatopancreas. ROI and SOI were estimated respectively by standard formulas and grading between 0-4 based on the percentage of white spot syndrome virus WSSV positive cells in selected fields of microscope. The results were confirmed by conducting nested PCR method. The SOI of Parapenaeopsis stylifera was estimated in grade four and its ROI was about 85% as the most susceptible species. Histopathologic infection of Metapenaeus affinis shrimp by WSD was observed also during this study.

Andamiajes tridimensionales tipo esponjas basados en bioconjugados colágeno-quitosano como potencial biomaterial para aplicaciones en ingeniería de tejidos

We isolated chitosan from native shrimp waste streams and collagen from tilapia skin waste; composite materials were successfully obtained by mixing chitosan with collagen (80:20 v/v). Chitosan-collagen composites were formulated as a 3D sponge-like scaffold, applying previously developed methodologies involving solvent casting and freeze drying. Chitosan-collagen 3D scaffolds were characterized according to its thermal behavior (TG) and morphology (SEM). Finally, we study the effect of the addition of a porogenic agent on the water absorption capacity and morphology of the 3D scaffolds.

Relationship of mangrove environment to the shrimps and milkfish production in silvofishery area of Blanakan, Subang, West Java

Abstract. Suryaperdana Y, Soewardi K, Mashar A. 2012. Relationship of mangrove environment to the shrimps and milkfish production in silvofishery area of Blanakan, Subang, West Java. Bonorowo Wetlands 2: 74-85. Silvofisheries represent an integrated approach to conserving and utilizing mangrove resources to maintain a relatively high level of integrity in the mangrove area while capitalizing on the economic benefits of brackishwater aquaculture. This research aims to assess the environmental conditions of mangrove ecosystem condition and its relation to farmed shrimp, milkfish, and nature shrimp production in the silvofishery area Blanakan, Subang, West Java. And to see the relationships between the mangroves with the production of fisheries, then analyzed by the method of regression analysis. An attempt has been made to relate the surface areas of mangroves and the commercial shrimp production in those areas and adjacent waters in Indonesia. A significant linear relationship (? = 0.05) was obtained between these two variables as expressed in an equation: y = 3.783 x +23.13, with r2 value of 90.2% where Y is kg the nonfarming production (natural shrimp) and X is the mangrove surface. This relationship indicates that the shrimp production increases with the size of the mangrove area, implying that any reduction of the tidal forests, purposes will cause a decrease in shrimp yield. Meanwhile, the result of regression analysis between the surface areas of mangrove with farming production (shrimp and milkfish) obtained the equation y = 0, 819x 235.3 with a value of r2 = 30.5%. The existence of mangroves can affect environmental conditions, the content of chlorophyll-a relatively higher, stable pH, and DO relatively better. Meanwhile, farming production (shrimp and milkfish) showed uncertain conditions because the success of farmed fish (shrimp and milkfish) is more determined by the management of ponds.

Growth, Reproductive Performances, and Brood Quality of Long Snout Seahorse, Hippocampus guttulatus, Fed Enriched Shrimp Diets

This investigation examined the effect of using enriched shrimp (Atlantic ditch shrimp, Palaemonetes varians) diets on growth of long snout seahorse, Hippocampus guttulatus, and its effect on the reproduction rate and brood quality. Three diets were (1) natural wild‐caught shrimp (natural shrimp diet‐control diet), (2) wild‐caught shrimp fed an artificial feed for 10 d (enriched shrimp diet), and (3) wild‐caught shrimp fed one large meal of artificial diet and immediately frozen (ingested artificial feed shrimp diet). These diets were fed to seahorses during a 12‐wk growth trial. At the end, significant differences on the final wet weight were found between seahorses fed the three different treatments (P < 0.009). Seahorses fed ingested artificial feed shrimp diet had more broods (9), generated more juveniles per brood (299 ± 87), and significantly bigger juveniles (12.4 ± 1 mm) than seahorses fed natural shrimp diet and enriched shrimp diet. Significant differences in the morphometry of juveniles hatched from parents fed the three different dietary treatments (Wilk's λ = 0.2, F(6,460) = 47.41, P < 0.0001) were also found. Results indicate that the combined use of a natural diet (shrimp) and an artificial diet benefit growth and feed utilization by seahorses and have a direct impact on the reproductive rate and brood quality of H. guttulatus.

Complex impacts of an invasive omnivore and native consumers on stream communities in California and Hawaii

The effects of invasive species on native communities often depend on the characteristics of the recipient community and on the food habits of the invasive species, becoming complicated when the invader is omnivorous. In field enclosure experiments, we assessed the direct and interactive effects of an invasive omnivorous crayfish (Procambarus clarkii) and either native herbivorous snails (Physella gyrina) or shrimp (Atyoida bisulcata) on stream communities in California and Hawaii, respectively. Based on literature data and the characteristics of each study site, we predicted that crayfish would affect primarily algal-based trophic linkages in an open California stream but detritus-based trophic linkages in a shaded Hawaiian stream, with trophic cascades mediated through crayfish effects on primary consumers being observed in both systems. As predicted, crayfish in California directly reduced periphyton, filamentous algae, sediment, and snail levels, but generated a cascade by decreasing snail densities and increasing periphyton biomass. Contrary to prediction, crayfish did not reduce total invertebrate biomass. As predicted, crayfish in Hawaii reduced leaf litter, filamentous algae, and benthic invertebrate biomass. Contrary to our predictions, however, a trophic cascade was not observed because shrimp did not affect periphyton levels, crayfish did not reduce shrimp abundance, and crayfish had greater negative impacts on filamentous algae than did shrimp. Our findings highlight that the same invasive species can generate different effects on disparate systems, probably as mediated through the availability of different food types, flexibility in the invasive species' food habits, and complex pathways of trophic interaction.

Palaemon macrodactylusRathbun 1902 (Oriental Shrimp) in New York: Status Revisited

Abstract Based upon studies between 2001 and 2010 and the continued presence of adult shrimp including gravid females, Palaemon macrodactylus (Oriental Shrimp) is established in the estuarine waters of New York City. In summer 2010, we sampled a 1000-m2 area of the East River and found that P. macrodactylus represented 4.3% of the total shrimp population, and 15.2% of the Palaemonidae (84.8% consisted of the native species Palaemonetes vulgaris [Common Grass Shrimp]). In 2001/2002, P. macrodactylus comprised 4.2% of all palaemonids, suggesting an increase in the past decade of non-native relative to native palaemonids. While not yet appearing to be “invasive” based upon population size, the feeding habits and reproductive biology of P. macrodactylus suggest that future interactions with native shrimp may occur. A key to regional shrimp is presented.

Evaluation of Most-Probable-Number–PCR Method with Internal Amplification Control for the Counting of Total and Pathogenic Vibrio parahaemolyticus in Frozen Shrimps

The most-probable-number (MPN) method is often time-consuming for the isolation, detection, and quantification of Vibrio parahaemolyticus from natural sources. MPN counting of V. parahaemolyticus bacteria usually involves the isolation of typical V. parahaemolyticus colonies on selective medium, with subsequent confirmation by biochemical identification. In this study, we evaluated the use of a PCR on MPN enrichment cultures (MPN-PCR) for the direct detection of total and pathogenic V. parahaemolyticus cells in frozen shrimp. This reaction targeted the R72H, tdh, and trh sequences. An internal amplification control was added to the samples before R72H amplification. There was an excellent correlation between the results of the two methods for artificially inoculated and natural shrimp samples. Of 36 natural samples, 28 tested positive for the presence of V. parahaemolyticus, with an MPN value of 2 × 10(-1) to 9.2 × 10(1) per g. No pathogenic V. parahaemolyticus cells were detected. The test had a detection limit of one V. parahaemolyticus organism per g and was completed within two working days. These results support the use of the combination of PCR with MPN for the detection of total or potentially pathogenic V. parahaemolyticus cells in frozen shrimp.

Urban impacts on tropical island streams: Some key aspects influencing ecosystem response

Improving our understanding of the impacts of urbanization on tropical island streams is critical as urbanization becomes a dominant feature in tropical areas. Although the “urban stream syndrome” has been successful in summarizing urban impacts on streams, the response of some island streams is different to that expected. Here we review available information on urban impacts to tropical island streams and describe unique responses to urbanization. We identified three key aspects that play particularly important or unique roles in determining tropical-island stream integrity: biotic response to water pollution, movement barriers along the stream network, and altered geomorphology that results in habitat loss. As expected, water pollution negatively impacts stream ecosystems in tropical islands and in some regions impacts can be severe, as untreated wastewaters are directly discharged into streams. While aquatic insects show the expected responses to pollution, other native fauna (e.g., shrimps and fishes) appear to be less impacted by moderate levels of pollution. Movement barriers along the stream network are especially important as much of the tropical island fauna have diadromous (either amphidromous or catadromous) life histories. Most native freshwater mollusks, shrimps, and fishes inhabiting tropical islands are diadromous and depend on unimpeded connections between freshwater and marine environments to complete their life cycles. The presence of these species in urban streams is best explained by longitudinal connectivity rather than by the degree of urban impact. Finally, in streams that remain connected to marine environments, the presence of native shrimps and fishes is strongly related to the physical habitat. Fish assemblages in channelized and severely altered stream reaches are almost completely devoid of native fauna and tend to be dominated by non-native species. In contrast, relatively diverse shrimp and fish assemblages can be found in reaches that retain their physical habitat complexity, even when they are impacted by urbanization. Our understanding of urban impacts on tropical island streams remains limited. However, the identification of key aspects can help us better understand urban impacts on streams in tropical islands, and best focus our management and research efforts to protect these unique ecosystems.

Generation of a comprehensive panel of crustacean allergens from the North Sea Shrimp Crangon crangon

BackgroundPublished data on crustacean allergens are incomplete. The identification of tropomyosin (TM), arginine kinase (AK), sarcoplasmic Ca-binding protein (SCP) and myosin light chain (MLC) as shrimp allergens are all important contributions but additional allergens are required for the development of a complete set of reagents for component resolved diagnosis and the exploration of novel vaccination strategies. MethodsThe North Sea shrimp (Crangon crangon), which is frequently consumed in Europe, served as a model organism in this study. TM and AK were directly cloned from mRNA based on sequence homology and produced as recombinant proteins. Additional IgE-reactive proteins were isolated by preparative SDS-PAGE and identified by mass spectrometry and corresponding cDNAs were cloned and expressed in E. coli. The relevance of the 6 cloned crustacean allergens was confirmed with sera of 31 shrimp-allergic subjects, 12 of which had a positive double-blind, placebo-controlled food challenge (DBPCFC) to shrimp and 19 a convincing history of food allergy to shrimp, including 5 cases of anaphylaxis. Quantitative IgE measurements were performed by ImmunoCAP. ResultsSix recombinant crustacean proteins: TM, AK, SCP, a novel MLC, troponin C (TnC), and triosephosphate isomerase (TIM) bound IgE in ImmunoCAP analysis. Specific IgE to at least one of these single shrimp allergens was detected in 90% of the study population, thus the in vitro diagnostic sensitivity was comparable to that of shrimp extract (97%). In 75% of the subjects, the combined technical sensitivity was similar to or greater with single shrimp allergens than with natural shrimp extract. ConclusionsWe identified six IgE-binding proteins from C. crangon, three of which have not before been described as allergens in crustaceans. This extensive panel of shrimp allergens forms a valuable asset for future efforts towards the identification of clinically relevant biomarkers and as a basis to approach patient-tailored immunotherapeutic strategies.

Tropomyosin IgE-positive results are a good predictor of shrimp allergy

Shrimp is a common cause of food allergy. Our aims were to determine the value of IgE antibodies in the diagnosis of shrimp allergy and to study red shrimp (Solenocera melantho) tropomyosin both as a new allergen and as a cross-reactive IgE-binding protein. We have studied 45 subjects. Skin prick test (SPT) was carried out in all subjects, and specific IgE (sIgE) to shrimp, recombinant and natural shrimp tropomyosins rPen a 1 and nPen m 1, recombinant Der p 10, and Dermatophagoides pteronyssinus was assessed by fluoroimmunoassay and/or immunoblotting. Double-blind, placebo-controlled food challenges were carried out to confirm diagnosis of shrimp allergy. Also, in vitro inhibition tests were performed to evaluate cross-reactivity. Shrimp allergy was confirmed in 18 shrimp-allergic patients. Skin prick test and IgE antibodies to shrimp were positive in all shrimp-allergic patients; sIgE to rPen a 1 was detected in 98% of these patients. Of the 18 shrimp-tolerant patients, 61% had positive SPT to shrimp, 55% were IgE-positive to shrimp, and 33% showed IgE antibodies to rPen a 1. Determination of IgE to rPen a 1 yielded a positive predictive value of 0.72 and a negative predictive value of 0.91. IgE levels to rPen a 1 provided additional value to the diagnosis of shrimp allergy. Some allergens in mite extract are recognized by patients who are allergic to shrimp, though their clinical relevance remains unknown.

Potential impacts of non-native channel catfish on commercially important species in a Japanese lake, as inferred from long-term monitoring data

Biological invasions are among the most serious threats to freshwater biodiversity. Analysis of long-term data can be a positive first step toward properly identifying the ecological and economic damage caused by invasive species. This study assessed the potential impacts of invasive channel catfish (Ictalurus punctatus), which have multiplied dramatically since around 2000 in Lake Kasumigaura, Japan, on native fish and shrimp and the commercial fishery using fishery-independent, quantitative long-term monitoring data (1993–2007). Temporal changes in abundance of 17 native fish species and one native shrimp species were analysed, and their sensitivity was evaluated, measured as change in relative abundance to the increase in I. punctatus abundance, was evaluated. A trait analysis of 18 species was performed in an attempt to investigate biological traits related to a negative sensitivity to I. punctatus invasion. After controlling for the effect of trophic status (total nitrogen and total phosphorus), nine of the 18 native species declined significantly through time and showed negative sensitivity to the increase in I. punctatus abundance; these included all four species used as raw materials for Japanese traditional processed foods. The trait-based analysis also revealed that benthic species and/or the species with a narrow diet range have decreased in abundance with increasing I. punctatus abundance. This suggests that competition for food, rather than predation by I. punctatus, is an important mechanism that results in a negative impact on native species. This study suggests that I. punctatus invasion may change the native community composition and negatively influence commercially important species, leading to a reduction in the provision of ecosystem goods. Copyright © 2011 John Wiley & Sons, Ltd.

A novel integrase-containing element may interact with Laem-Singh virus (LSNV) to cause slow growth in giant tiger shrimp

BackgroundFrom 2001-2003 monodon slow growth syndrome (MSGS) caused severe economic losses for Thai shrimp farmers who cultivated the native, giant tiger shrimp, and this led them to adopt exotic stocks of the domesticated whiteleg shrimp as the species of cultivation choice, despite the higher value of giant tiger shrimp. In 2008, newly discovered Laem-Singh virus (LSNV) was proposed as a necessary but insufficient cause of MSGS, and this stimulated the search for the additional component cause(s) of MSGS in the hope that discovery would lead to preventative measures that could revive cultivation of the higher value native shrimp species.ResultsUsing a universal shotgun cloning protocol, a novel RNA, integrase-containing element (ICE) was found in giant tiger shrimp from MSGS ponds (GenBank accession number FJ498866). In situ hybridization probes and RT-PCR tests revealed that ICE and Laem-Singh virus (LSNV) occurred together in lymphoid organs (LO) of shrimp from MSGS ponds but not in shrimp from normal ponds. Tissue homogenates of shrimp from MSGS ponds yielded a fraction that gave positive RT-PCR reactions for both ICE and LSNV and showed viral-like particles by transmission electron microscopy (TEM). Bioassays of this fraction with juvenile giant tiger shrimp resulted in retarded growth with gross signs of MSGS, and in situ hybridization assays revealed ICE and LSNV together in LO, eyes and gills. Viral-like particles similar to those seen in tissue extracts from natural infections were also seen by TEM.ConclusionsICE and LSNV were found together only in shrimp from MSGS ponds and only in shrimp showing gross signs of MSGS after injection with a preparation containing ICE and LSNV. ICE was never found in the absence of LSNV although LSNV was sometimes found in normal shrimp in the absence of ICE. The results suggest that ICE and LSNV may act together as component causes of MSGS, but this cannot be proven conclusively without single and combined bioassays using purified preparations of both ICE and LSNV. Despite this ambiguity, it is recommended in the interim that ICE be added to the agents such as LSNV already listed for exclusion from domesticated stocks of the black tiger shrimp.

Biochemical characterization of trypsins from the hepatopancreas of Japanese sea bass (Lateolabrax japonicus)

A cationic trypsin (trypsin A) and an anionic trypsin (trypsin B) were highly purified from the hepatopancreas of the Japanese sea bass (Lateolabrax japonicus) by ammonium sulfate precipitation, column chromatographies of DEAE-Sepharose and Sephacryl S-200 HR. Purified trypsins revealed single band on SDS-PAGE and their molecular masses were 21 kDa and 21.5 kDa, respectively. Trypsins A and B exhibited maximal activity at 40°C, and shared the same optimal pH at 9.0 using Boc-Phe-Ser-Arg-MCA as the substrate. The two trypsins were stable up to 45°C and in the pH range from 7.0 to 11.0. Trypsin inhibitors such as Pefabloc SC, PMSF and benzamidine are effective to these two enzymes and their susceptibilities were similar. Apparent K(m)s of trypsins A and B were 1.12 and 0.7 μM and k(cat)s of them were 72.08 and 67.79 S(-1) for Boc-Phe-Ser-Arg-MCA, respectively. The N-terminal amino acid sequences of the two trypsins were determined to the 24th residues, which were highly identical to trypsins from other species of fish while trypsins A and B only shared 45.8% identity. The digestive effect of the two trypsins on native shrimp muscular proteins indicated their effectiveness in the degradation of food proteins.

Effect of processing treatments on the white spot syndrome virus DNA in farmed shrimps (Penaeus monodon)

To investigate the effect of processing treatments on the destruction of white spot syndrome virus (WSSV) DNA in WSSV-infected farmed shrimps (Penaeus monodon). The presence of WSSV was tested by single step and nested polymerase chain reaction (PCR). The primers 1s5 & 1a16 and IK1 & IK2 were used for the single step PCR and primers IK1 & IK2-IK3 & IK4 were used for the nested PCR. Various processing treatments such as icing, freezing, cooking, cooking followed by slow freezing, cooking followed by quick freezing, canning, and cold storage were employed to destroy the WSSV DNA. Of the processing treatments given, cooking followed by quick freezing was efficient in destroying WSSV DNA in WSSV-infected shrimp products. Canning, and cooking followed by slow freezing process had some destructive effect on the WSSV DNA, as WSSV DNA in such processed shrimp products was detected only by nested PCR. Icing, slow freezing, quick freezing, and cooking processes had no effect on the destruction of WSSV DNA. A gradual increase in the destruction of WSSV DNA was observed as the cold storage period increased. The results indicated that cooking followed by quick freezing process destroy the WSSV DNA. WSSV can be destroyed by cooking followed by quick freezing and this combined process can reduce the disease transmission risks from commodity shrimps to native shrimps.

Total and pathogenic Vibrio parahaemolyticus in shrimp: Fast and reliable quantification by real-time PCR

Vibrio parahaemolyticus is found in aquatic environments and is the leading cause of gastroenteritis due to seafood consumption worldwide. We evaluated a quantitative real-time PCR (Q-PCR) assay with hydrolysis probes, to determine whether this method could be used for the efficient counting of total, tdh and trh-positive V. parahaemolyticus in shrimps. We assessed the specificity of this assay, using 62 strains from 12 non target bacterial species of the Vibrio, Photobacterium, Shewanella and Aeromonas genera. Only V. parahaemolyticus with the appropriate target gene generated a fluorescent signal. We assessed the robustness of this assay, by analyzing spiked shrimps by Q-PCR and traditional culture methods, using most probable number (MPN)-PCR. After a 6 h enrichment period, the assay successfully detected total and pathogenic V. parahaemolyticus in shrimps samples spiked with less than 5 V. parahaemolyticus cells/g of shrimp. The Q-PCR results obtained were compared with those obtained by most probable number (MPN)-PCR format. An excellent correlation between the two methods was observed in all cases (R 2 > 0.9742). The application of this Q-PCR assay to 85 natural shrimp samples also resulted in the successful quantification of V. parahaemolyticus in this matrix, and the counts obtained were correlated with those obtained by (MPN)-PCR ( P = 0.2598). Thus, this rapid and sensitive Q-PCR can be used to quantify V. parahaemolyticus in natural shrimp samples. This assay could be proposed, in response to the demands of the European Commission, as a tool for testing for the presence of vibrios in crustaceans, making it possible to legislate in this domain.

Effect of the Maillard reaction with xylose on the emulsifying properties of a shrimp hydrolysate ( Pandalus borealis)

The emulsifying properties of native shrimp hydrolysate (SH) and its sugar-conjugate (GSH) were studied at two concentrations (0.5% (w/w) or 1.5% (w/w)). GSH was obtained through the Maillard reaction in mild conditions (xylose; 65 °C; pH = 6.5; 4 h). Size exclusion chromatography of GSH demonstrated the occurrence of new fractions with higher molecular weights, resulting from the Maillard reaction. GSH showed a loss of ~ 30% of available amino groups expressed in terms of lysyl residues. Emulsions containing GSH significantly retarded and decreased creaming at both concentrations more than SH, and they had the highest consistency index values (K in mPa s n) and apparent viscosities ( η app in mPa s). Finally, increasing SH and GSH concentrations in emulsions decreased their flow index values ( n dimensionless) by 32% and 16% respectively. From these results, the Maillard reaction may be a useful approach for improving emulsifying properties of SH.

Viability of culturing pink shrimp Farfantepenaeus duorarum in low-salinity groundwater from the Yucatán Peninsula (SE, México)

In the Gulf of Mexico constraints linked to the supply of post-larvae (PL) and legal pressures associated with the introduction of a non-native species have been the motives behind research on the aquaculture of the native shrimp. In the present study, the growth and survival of 25-day-post-larvae (PL-25) of the pink shrimp Farfantepenaeus duorarum in saline groundwaters were evaluated. During the experiment the shrimps were acclimated from 36 psu to 5 psu utilizing various acclimation times ( T1 = 38 h, T2 = 42 h, and T3 = 45 h) with a variable rate of salinity reduction ( T1 = 9.9% h − 1 , T2 = 11.8% h − 1 , and T3 = 11.4% h − 1 ). After a 1-day acclimation period there were no differences ( P > 0.05) in survival between treatments (80.7 ± 3.5%). The salinity reduction rate of T1 (low acclimation time) was selected to acclimatize the PL for the nursery experiment due to the high survival rate recorded after the salinity stress test. During the nursery experiment, shrimp at a density of 80 PL m − 2 had the highest growth rate (20 mg week − 1 ) ( F (2,9) = 10.73; P < 0.05) and survival rate (79%) ( F (2,9) = 4.93; P < 0.05) in comparison to other densities (150 PL m − 2 ; 250 PL m − 2 ). The PL growth was adjusted to a non-linear regression function (0.030 * e (0.035 * d)). Shrimp at 80 PL m − 2 ( t = 0.87) and 150 PL m − 2 ( t = 1.54) showed isometric growth (Ho = b = 3). Temperature was the only environmental variable that explained the most consecutive additional variance (80.1%) in the PL weight. The temperature–growth response curve was fitted to a generalized additive model (GAM). Results from this research demonstrate that F. duorarum (PL-25) can be successfully acclimated to low-salinity (5 psu) conditions with a high percentage of survival and an acceptable growth rate in the nursery phase (45 days). In the future efforts should be made to improve survival at higher densities in order to make production profitable.

Purification of Native Shrimp Tropomyosin by Affinity Chromatography with Cross-reactive Antibody

Purification of Native Shrimp Tropomyosin by Affinity Chromatography with Cross-reactive Antibody