The inland farming of penaeid shrimp in low-salinity waters is now de facto in many regions of the world, yet there is little information pertaining to the suitability of waters with various ionic compositions for shrimp culture. In the present study, short-term (48 h) survival of Pacific white shrimp, Litopenaeus vannamei postlarvae (PL), and long-term (4 weeks) growth and survival of juvenile L. vannamei in various inland saline ground waters were evaluated. A correlation between survival and growth of PLs and the ionic composition of the waters was performed. Short-term bioassays were conducted on 10-, 15-and 20-day-old postlarvae using waters from various wells. Salinity was decreased at a rate of 4 ppt h À 1 using fresh water from 24 ppt until a salinity of 2 ppt above the target salinity was reached. Water in the containers was then slowly exchanged with water from inland saline wells. Survival of the PLs was evaluated 48 h after the start of acclimation. In the second study, four replicates of 15 juveniles were placed in 144-l square tanks containing various saline well waters from west Alabama. Growth and survival were evaluated after 4 weeks. The ionic makeup of the various inland well waters from Alabama, Florida, Mississippi and Texas was analyzed to characterize each source. Survival of PL 10 shrimp in some of the waters was similar to survival in the low-salinity reconstituted seawater control and was significantly different from the control in other waters. Survival of PL 15 was greater than survival of PL 10 but similar to PL 20 . Some waters were unsuitable for shrimp culture at all PL stages tested. Survival and growth of the juveniles paralleled results of the short-term bioassays. Shrimp survived and grew well in waters in which more than 90% of the postlarvae acclimated and survived in. Juvenile survival and growth were intermediate and low in waters in which PL acclimation was intermediate and low, respectively. Survival appears to be positively correlated with ions such as K, Mg and SO 4 and negatively correlated with a high concentration of iron. D

Shrimp culture in inland low-salinity well water is a growing industry in many regions of the world, including the southern United States of America. Although shrimp culture techniques in waters of marine origin are well established, they are not necessarily applicable to shrimp culture in low salinity well water. Inland well waters tend to vary among each other in salinity and ion profiles. If shrimp culture using inland well water is to develop further, we must systematically deal with production problems which include 1) identification of suitable water sources 2) development of acclimation and stocking procedures 3) identify specific nutritional requirements for low salinity environments. This paper summarizes work that we have done to a) assist in the development of acclimation procedures for Litopenaeus vannamei postlarvae (PL), b) evaluate a variety of well water sources for their culture potential and identify mineral imbalances that may be correlated to poor survival and growth c) provide baseline data for the identification of nutritional manipulations that may mitigate the variable survival that has plagued low salinity production systems. Results suggest that PL survival in native seawater is affected by an interaction between PL age and water salinity. In native seawater, ten day old PL exhibited greater survival at salinities greater than 4 ppt than at salinities of 2 ppt and lower. Fifteen and twenty-day old PL survived in salinities as low as 1 ppt. Survival of PL in well water varied among water sources, and was affected by the concentration of various ions such as potassium (K + ), magnesium (Mg 2+ ), and sulphate (SO 4 2-

Juvenile bluegills Lepomis macrochirus were reared at four densities in indoor aquaria to evaluate the effects of stocking density on growth, survival, condition, and feed efficiency. Fish (mean weight, 1.76 g) were stocked into 100-L aquaria containing 60 L of water at rates of 10, 20, 30, and 40 fish per aquarium (167, 334, 500, and 667 fish/m 3 , respectively). The growth trial was conducted over an 11-week period during which the fish were offered a 45%-protein commercial ration in slight excess. At the termination of the study, the mean weights as well as the lengths and weights of individual fish in each tank were recorded. Size was inversely related to stocking density. The final weights of the fish decreased significantly as density increased, with fish stocked at a density of 167/m 3 having a mean weight of 10.7 g and those stocked at 667/ m 3 a mean weight of 7.3 g. The percent weight gain and feed efficiency also decreased as stocking density increased. No significant differences in relative condition were found among treatments. The results of this study suggest that density-dependent, nonaggressive competition resulted in reduced growth and feed utilization.

Siganus rivulatus is increasing in countries on the Eastern Mediterranean, Red Sea and Arabian Gulf. However, information on environmental tolerances and requirements for optimal growth are scarce. In the present work, the temperature requirements for spinefoot rabbit¢sh were investigated in two experiments. In the ¢rst experiment, juvenile rabbit¢sh were distributed into eight 180 L square tanks at 12 ¢sh per tank. The temperature in four tanks was reduced at a rate of 1 1C day À1 and in four tanks was increased by 1 1C day À1 until the ¢sh stopped feeding. Minimum and maximum temperatures for feeding were recorded. In the second experiment, the ¢sh were placed in four temperature treatments (17, 22, 27, 32 1C) at four replicates per treatment for 8 weeks. Survival and growth were evaluated. Fish stopped feeding at 14 and 36 1C. Their maximum growth rate was at 27 1C, and survival was 100% in all treatments. The relationship between speci¢c growth rate and temperature was parabolic, described by the equation: SGR 5 À 0.0014 (T 3 )10.0798 (T 2 ) À 1.3089 (T)16.7342. The results show that S. rivulatus is a eurythermal ¢sh whose optimal temperature for growth is circa 27 1C.

Shrimp farmers using inland low-salinity waters in west Alabama have traditionally used agricultural fertilizers (K-MagÒ, muriate of potash) to raise pond water levels of potassium (K) and magnesium (Mg) to improve the rearing medium for Litopenaeus vannamei. Laboratory and farm trials were performed to investigate the potential of using dietary supplementation of Mg instead of costly agricultural fertilizers. A 5-wk laboratory trial was devised to test four diets with varying levels of Mg supplementation (0, 0.15, 0.30, and 0.60% Mg chelate) using a magnesium chelate (MgC)-amino acid complex. Juvenile shrimp were stocked into artificial low-salinity water (5 ppt) designed to contain low levels of Mg. A farm trial was also conducted to test the same diets under field conditions. Although both laboratory and on-farm trials revealed a trend for increased growth using the diet with the highest Mg supplement, results were not significantly different. The use of magnesium chelates as dietary supplements at levels higher than the requirement level to enhance survival, growth, and osmoregulatory capacity of shrimp reared in inland low-salinity well waters appeared to have limited potential. Until effective specialized diet formulations are produced, farmers should continue to supplement pond waters with fertilizers containing K and Mg.

Mediterranean, Red Sea, and Arabian Gulf nations. However, culture protocols for commercial production are incomplete. In this work, we evaluated the benefits of size sorting S. rivulatus juveniles before stocking. Two experiments were performed. In the first experiment, juveniles were size sorted into three different groups: small (5.5 g), medium (8.7 g), and large (12.1 g), and 15 fish were stocked per tank in a recirculating system of 180-L tanks with three replicates per treatment. Two additional treatments were established: a mixed treatment consisting of five fish from each size category stocked together and a small treatment offered as much feed daily as the medium treatment. Feed was offered at 4% body weight daily for 8 wk. Survival was greater than 95% in all treatments. Average final weights of the fish at harvest were 52.2, 38.1, 28.3, 39.6, and 30.5 g for large, medium, small, mixed, and small with high-ratio treatments, respectively. Fish in the large treatments grew faster than fish in all other treatments. In the second experiment, fish were trapped off the Beirut beach in April, June, and August 2007. Individual weight and length and condition index of each fish were determined. Males and females were differentiated by identifying testicular and ovarian tissue, respectively. Gender identification was performed at 10× magnification. There were no differences in length and weight between males and females in all three samples collected. Results suggest that size grading of juvenile rabbitfish will maximize culture production by selecting faster growing fish with better condition indices but will not select for gender because S. rivulatus juveniles (10.6-12.1 cm) do not exhibit sexual size dimorphism.

Redclaw aquaculture has developed at a rapid pace during the past few years, yet no specialized diet for the species has been developed. The present study was designed to evaluate whether soybean-based diets containing either ¢shmeal (FM), poultry by-product meal (PBM), ground peameal (GPM) or distillers dried grains with solubles (DDGS) meal as a protein source are suitable for redclaw aquaculture. Juvenile redclaw cray¢sh Cherax quadricarinatus (0.125 AE 0.025 g) were stocked into 20 rectangular tanks at a stocking density of 12.5 m À 2 for 8 weeks. Cray¢sh in four replicate tanks were maintained on one of ¢ve diets formulated to contain 35% crude protein and 7.1% lipids. Each 100 g of diet contained 25 g of protein from soybean meal (SBM) and 10 g of protein from the alternative protein sources mentioned above. A ¢fth treatment that did not receive feed was included to account for growth from natural productivity. There were no sig-ni¢cant di¡erences in survival (86^90%), growth (3.84^4.98 g animal À 1 ) or feed conversion ratio (2.102

White sea bream Diplodus sargus is a valued table fish in the Mediterranean region and elsewhere (Black Sea and Eastern Atlantic), and is a candidate aquaculture species in various countries. Understanding dietary protein requirements and protein to energy ratios is imperative for development of a successful culture of this species. A ten week experiment was performed to estimate growth performance of D. sargus juveniles offered diets with various levels of protein and energy. Six diets were formulated to contain three levels of protein (25, 35 and 45%) plus two levels of lipids (8 and 12%), and were offered to white sea bream juveniles in triplicate tanks, three times daily, to satiation. Survival was greater than 93% in all treatments. Growth increased with increasing dietary protein and increasing lipid content of the diets. Feed intake increased with increasing dietary protein but was not affected by dietary lipid levels. Protein efficiency decreased with increasing dietary protein levels. Moisture, protein and ash levels in the fish were not affected by dietary protein but body lipid content increased with increasing dietary protein. Dietary protein levels seemed to affect red blood cells. A greater proportion of immature red blood cells were found in blood of fish offered the 25% and the 45% protein diets than in blood of fish offered the 35% protein diet. Results of the present work suggest that a 45% protein, 12% lipid diet results in good growth of D. sargus 4 Shymaa M. Shalaby et al.

Anaesthetics are used in aquaculture and fisheries to facilitate routine procedures, such as capture, handling, transportation, tagging, grading and measurements that can often cause injury or induce physiological stress. Two experiments were performed to assess the efficacies of four anaesthetic agents, clove oil, benzocaine, 2-phenoxyethanol and MS-222 on juvenile marbled spinefoot rabbitfish (Siganus rivulatus). In the first experiment we tested the lowest effective doses that produced induction and recovery times in 3 min or less and 5 min or less respectively. Dosages were 70 mg L À1 for clove oil, 60-70 mg L À1 for benzocaine, 400 lL L À1 for 2-phenoxyethanol and 100-125 mg L À1 for MS-222. In the second experiment, we determined optimal concentrations of the four anaesthetics if they were to be used to transport rabbitfish fry. Anaesthetic concentrations suitable for handling and transport were: 10-15 mg L À1 of MS-222, 5-10 mg L À1 of benzocaine, 5 mg L À1 of clove oil and 50-100 lL L À1 of 2-phenoxyethanol. All anaesthetic agents are acceptable for use on S. rivulatus, however, 2-phenoxyethanol, MS-222 and clove oil appear to be more suitable than benzocaine. Further studies need to be conducted on effects of high and low doses of anaesthetic agents on physiology of marbled spinefoot.

The redclaw crayfish, Cherax quadricarinatus, is a freshwater decapod crustacean displaying a number of physical, biological, and commercial attributes that make it suitable for commercial aquaculture. Interest in redclaw crayfish, both for aquaculture and aquarium trade, has resulted in wide translocations of the species within Australia, south-east Asia, and Central/South America. The redclaw aquaculture industry has been growing rapidly since the mid-1980s in tropical and sub-tropical regions of the world. Redclaw aquaculture is done mostly in extensive pond systems, but interest in developing more intensive systems is increasing. The present manuscript reviews current knowledge and trends of redclaw aquaculture, and areas where further research is needed are identified. Nutrition and reproduction of redclaw were recently reviewed in other manuscripts and those are summarized here. The present manuscript emphasizes environmental tolerances, diseases, aquaculture techniques, and marketing.

Nanoparticles (NPs) can be ingested by organisms, and NPs with antimicrobial properties may disrupt beneficial endogenous microbial communities and affect organism health. Zebrafish were fed diets containing Cu-NPs or Ag-NPs (500 mg kg À1 food), or an appropriate control for 14 d. Intestinal epithelium integrity was examined by transmission electron microscopy, and microbial community structure within the intestine was assessed by denaturing gradient gel electrophoresis (DGGE) of partial 16S rRNA. No lesions were observed in intestinal epithelia; however, presence of NPs in diets changed intestinal microbial community structure. In particular, some beneficial bacterial strains (e.g., Cetobacterium somerae) were suppressed to non-detectable levels by Cu-NP exposure, and two unidentified bacterial clones from the Firmicutes phylum were sensitive (not detected) to Cu, but were present in Ag and control fish. Unique changes in zebrafish microbiome caused by exposure to Ag-NP and Cu-NP indicate that NP ingestion could affect digestive system function and organism health.

Inland saline groundwater is abundant in various areas of the world but is not suitable for traditional agriculture irrigation and is also not suitable for marine aquaculture mainly because of potassium deficiencies. In the present work, we used marbled spinefoot rabbitfish Siganus rivulatus, as a model organism to investigate whether varying levels of aqueous K + affect survival and growth, and whether ambient K + has an effect on fish osmoregulation and haemolymph osmolality. A ten-week growth experiment was conducted where fish were reared in reconstituted inland saline water containing K + concentrations equivalent to 15%, 40% and 100% (denoted as: Trt15, Trt40, and Trt100, respectively) of potassium in 15 ppt seawater. A 15 ppt seawater treatment (CSW) was used as a control. Fish weight, length, survival, Fulton-type condition index, blood and water osmolality, and serum Na + and K + concentrations were evaluated. Gill NKA activity was also estimated. Fish reared in Trt15 died during week 8. At the end of the experiment (week 10), no differences were observed in fish survival and total length among treatments Trt40 and Trt100 and control (P>0.05). Final weight was less in Trt40 and Trt100 than in CSW. Fulton-type condition index results showed that Trt100 was more suitable for fish than Trt40, but still not as suitable as 15 ppt sea water. Sodium (Na + ) in serum was not affected by aqueous K + levels, whereas serum K + varied congruently with aqueous K + . Rabbitfish reared in Trt40 and Trt100 had greater blood osmolality than those reared in control seawater. Gill NKA activity also increased by 50% in Trt40 and Trt100 as compared to control. The present study shows that potassium-deficient 15 ppt inland well water is not suitable for long-term culture of Siganus rivulatus. Results suggest that inland saline well waters greatly increase activity of NKA and consequently energy expenditure. Furthermore, K + does not appear to be the only limiting mineral in inland low salinity groundwater that affects fish osmoregulation.

Commercial crustacean fisheries are dwindling while demand is growing. Aquaculture is expected to meet supply requirements, thus better egg production and hatchery management are required if the industry is to keep growing. In addition to hatchery management, methods that improve crustacean juvenile production by manipulating their endocrine system are being assessed. Redclaw Cherax quadricarinatus aquaculture technology is mature enough to grow into an important industry. However, further growth requires research on nutrition, disease and reproduction. The present manuscript reviews existing literature about redclaw reproduction, hatchery, and nursery technology. Further research is bound to improve monosex larval production or at least develop methods to improve growth in both sexes. The market for redclaw is growing, aquaculture in warm countries is increasing and research is improving aquaculture methodologies of the species. The future is bright.

The aim of the present study was to observe the antagonistic relationship of the probiotic Pediococcus acidilactici and the pathogen Vibrio (Listonella) anguillarum in the intestine of rainbow trout (Oncorhynchus mykiss) by using an ex vivo intestinal sac method. Rainbow trout (240-250g) were fed either a control diet (commercial diet: 43% protein, 20% lipid) or a probiotic diet (control diet supplemented with P. acidilactici [Bactocell] at log 7 CFU g -1 ) for two weeks. The anterior intestine was then isolated for an ex vivo challenge study and intestinal sacs formed by shutting one end of the intestinal portion. The sacs were filled with PBS solutions containing either no bacteria (as a control), the probiotic (P. acidilactici), the pathogen (V. anguillarum), or probiotic+pathogen and incubated for one hour. At the end of the exposure bacterial levels in the lumen were determined by culture based approaches and colonisation of the mucosa assessed with PCR-DGGE and electron microscopy (EM). Intestinal morphology (observation of gross morphological damage, ultrstructural differences and the quantification of goblet cells and intra epithelial lecuocyte numbers) and bacterial infection/translocation was assessed using light microscopy (LM) and EM.