Evaluating the Effects Related to Restocking and Stock Replenishment of Penaeus penicillatus in the Xiamen Bay, China

The quantitative evaluation of restocking and stock replenishment is essential for providing operational feedback and implementing adaptive management for future restoration projects. Since 2010, approximately 700 million juvenile shrimp (Penaeus penicillatus) have been released into Xiamen Bay, Fujian Province, China, each year, through stock replenishment programs. The recruited shrimp were sampled through three-year bottom trawl surveys from 2014 to 2017. The biological characteristics and catch equation were used to evaluate the effect of restocking and stock replenishment. The analysis uses the FAO-ICLARM Stock Assessment Tool (FISAT II) program. In general, there are two sources of recruitments—one from spawning brood stock and the other from released juvenile shrimp. We constructed an evaluation model for an effect evaluation based on Baranov’s catch equation to separate the initial recruitment volume using survey data. The relationship between body weight and total length was W =1.638 TL2.9307. There is no statistically significant difference between males and females. The von Bertalanffy growth parameters derived for prawns, using FiSAT II, were L∞ = 209.6 mm and K = 0.51 per year. In spring 2014, the initial resource amount was 49,200, while the ratio of effective recruitment and parent amount was 3.92. The survival rate of the released shrimp larvae, 1.88‱, seems to be very unsatisfactory. The resource amount in summer and autumn is higher than in winter and spring. Obviously, the restocking effect is lower and the programs need to be improved. To improve the restocking effect, the replenishment performance should be adjusted to reduce the mortality rate and increase its release effectiveness. Therefore, corresponding implementations are recommended, including standard extensive culture, reduction in stress during transportation, and temporary culture.

Evaluación de la respuesta productiva e inmune en juveniles de camarón Litopenaeus vannamei alimentado con mezclas probióticas

Shrimp diets with mixtures of probiotics (bacilli or yeasts) were evaluated on the production response and immunological effect on juvenile shrimp (Litopenaeus vannamei). The results showed a significant effect in growth, food consumption and feed conversion rate when probiotic diet was used. In addition, experimental diets with yeast mixture [C. insectorum (DH5), D. hansenii (DH6, and L1)] had a significantly higher amount of circulating haemocytes than those with bacilli [B. tequilensis (YC5-2), B. endophyticus (YC3-b) and B. endophyticus (C2-2)]. Shrimp fed both experimental diets (3x107 CFU mL-1) had a significantly higher growth and immune parameters when compared with the commercial diet. Both elements can contribute to the sustainable development and health of shrimp farming.

Genotoxicity by Pahs In Shrimp (Litopenaeus Vannamei) and Its Impact on The Aquaculture of Two Coastal Ecosystems of The Gulf of California, Mexico

During the lasts decades, aquaculture of several species have growth vertiginously around the world. In Mexico the shrimp aquaculture has been the most important. About 73-75 % of shrimp hatcheries are in coastal ecosystems of the states of Sonora and Sinaloa, located along the Gulf of California. In this States there is not oil industry; however, several industries and other activities discharge petroleum derivatives (imprudently or accidentally) into coastal waters; as happens in Teacapan estuary and Huizache-Caimanero lagoon. The aim of this work was to quantify the levels of PAHs in water of these ecosystems, and to evaluate the genotoxic damage to shrimp, under laboratory conditions. Water samples were taken during rainy and dry months from both coastal systems, and then analyzed by Gas Chromatography (GC). Once known the PAHs concentrations, lots of seven juvenile shrimp were exposed to sub-lethal concentrations of Naphthalene, Phenanthrene, Chrysene, Fluorene, Anthracene, Pyrene, Fluoranthene, Benzo(b)fluoranthene and Benzo(a)pyrene during 21 days, since these were the most frequently PAHs found. At end of exposure period, genotoxicity was evaluated by Comet assay, and presence of micro-nucleus in shrimp haemocytes. Results demonstrated genotoxic damage by presence of comets, and micro-nucleus more frequently in exposed shrimps than controls. Also, a growth decrease was observed in exposed shrimps. These results, indicate potential risk for shrimp aquaculture in Sinaloa and human health, since shrimp is exported and consumed locally, and because in some cases, experimental PAHs concentrations were lower than concentrations of some PAHs found in water of Teacapan estuary and Huizache–Caimanero lagoon.

Enhancement of shrimp health and immunity with diets supplemented with combined probiotics: application to Vibrio parahaemolyticus infections

The application of probiotics for disease control in aquaculture is now a convincing approach towards replacement of antibiotics, which can cause adverse effects in aquatic animals and humans. In this study, we combined 2 probiotics, Lactobacillus acidophilus and Saccharomyces cerevisiae, with shrimp feed to create 2 formulas (WU8 and WU9), which were fed for 10 d to juvenile shrimp Penaeus vannamei. The shrimps were then subjected to a challenge infection with Vibrio parahaemolyticus, the causative agent of acute hepatopancreas necrosis disease (AHPND). The protective effects of probiotics against bacterial infection were investigated through histopathology of the hepatopancrease and immunological evaluation of shrimp. Both WU8 and WU9 probiotic mixtures (1:1, at 108 and 109 CFU kg diet-1) increased blasenzellen hepatopancreatic epithelial cells and reduced pathology caused by AHPND. After 10 d of feeding, hemocyte parameters, including the total hemocyte count, percent of granular hemocytes, and phenoloxidase activity, increased significantly and were still increasing at 24 h post infection. Crustin and penaeidin 3 genes were also highly upregulated in hemocytes before and after 24 h of bacterial challenge and significantly upregulated in the hepatopancreas 1 to 5 d post-infection. A significantly higher survival rate was observed in shrimp fed with the probiotic supplemented diet (>90%) in comparison to the control group (60%). In conclusion, probiotic mixtures of L. acidophilus and S. cerevisiae reduced hepatopancreas pathology and protected shrimp from a challenge with AHPND.