David B. Rouse

Suitability studies of inland well waters for Litopenaeus vannamei culture

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. Salinitywasdecreasedatarateof4ppth 1 usingfreshwaterfrom24pptuntilasalinityof2pptabove 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 watersfromwestAlabama.Growthandsurvivalwereevaluatedafter4weeks.Theionicmakeupofthe various inland well waters from Alabama, Florida, Mississippi and Texas was analyzed to characterize each source. Survival of PL10 shrimp in some of the waters was similar to survival in the low-salinity reconstituted seawater control andwas significantly differentfrom the control in other waters. Survival of PL15 was greater than survival of PL10 but similar to PL20. 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 andsurvivedin.Juvenile survivalandgrowth wereintermediate andlowin watersinwhich PL acclimation was intermediate and low, respectively. Survival appears to be positively correlated with ions such as K, Mg and SO4 and negatively correlated with a high concentration of iron. D 2003 Elsevier Science B.V. All rights reserved.

Effects of dietary lipid level and source on growth and proximate composition of juvenile redclaw (Cherax quadricarinatus) reared under semi-intensive culture conditions

Abstract The influence of dietary lipid level on growth, survival, and proximate composition of juvenile redclaw crayfish was evaluated during a 12-week growth trial utilizing semi-intensive culture conditions. Four diets were formulated to be isoenergetic (17.58 kJ g −1 ) and isonitrogenous (30% crude protein). Three of the diets were designed to contain 4.2% (L4), 8.2% (L8) and 12.3% (L12) lipid in a 1:1 ratio of corn oil/fish oil. A fourth diet was formulated to contain 8.7% (LC8) lipid, with corn oil as lipid supplement. A fifth treatment (UF) was included in which the redclaw were not fed in order to estimate the contribution of primary production. Juvenile redclaw (4.08±0.2 g initial weights) were stocked at a density of 10 per tank in 15, 2.5-m 3 fiberglass tanks with three replicates per treatment. The trial was conducted in an outdoor flow-through water system. The redclaw in the unfed treatment gained 8.3 g whereas redclaw that received a prepared ration gained an average of 31.9 g. Hence, in this experiment natural productivity contributed about 26% of the weight gain of the redclaw maintained in outdoor tanks. Among the fed treatments, there were no significant differences in survival, final weight, growth, or feed utilization. The hepatosomatic index (HI) generally increased with lipid level and was influenced by the sex of the redclaw. Results indicated that in similar culture conditions, diets containing 4% lipid are sufficient for redclaw growth and survival when natural food is present.

Partial and total replacement of fish meal with soybean meal and brewer's grains with yeast in practical diets for Australian red claw crayfish Cherax quadricarinatus

Three feeding studies were conducted to evaluate the effects of total replacement of fish meal (FM) with a combination of soybean meal (SBM) and brewer’s grains with yeast (BGY) in diets for two separate strains of juvenile Australian red claw crayfish. In Experiment 1, three practical diets were formulated to be isonitrogenous (40% protein) and isocaloric (4.0 kcal available energy/g diet) and contained either 25%, 10%, or 0% fish meal. Variable percentages of SBM (35%, 46.8%, and 79.8%, respectively) and BGY-35 (0%, 30%, and 5%, respectively) replaced the fish meal. In Experiments 2 and 3, four practical diets were formulated to be isonitrogenous (40% protein) and isocaloric (4 kcal available energy/g diet) containing 24% or 0% fish meal. Diet 1 contained 24% fish meal, 23% SBM, and 0% BGY-35. A variable percentage of SBM (56.75%, 47.75%, and 40.75%, respectively) and BGY-35 (10%, 20%, and 30%, respectively) replaced the fish meal in the remaining three diets. In Experiment 1, after 8 weeks, juvenile red claw fed all three diets had no significant difference (P>0.05) in final weight, percentage weight gain, or survival, which averaged 7.90 g, 3848%, and 83%, respectively. In Experiment 2, after 8 weeks, juveniles fed all four diets had no significant difference in final weight, percentage weight gain, or specific growth rate which averaged 11.46 g, 977%, and 3.08%/day, respectively. Percentage survival was not significantly different among treatments and averaged 79%. In Experiment 3, after 8 weeks, juvenile red claw fed all four diets had

Treatment of harvest discharge from intensive shrimp ponds by settling

Abstract Effluent from intensively managed shrimp ponds was examined during harvest when ponds were drained. Concentrations of nutrients and solids in effluents were significantly higher during the final 20 cm of discharge (16% of pond volume), but greatest increases occurred during the final 5 cm of discharge (3.9% of pond volume). When the final 20 cm of pond discharge was allowed to settle, near maximum sedimentation for most variables occurred within 6 h. Settling removed total nitrogen less effectively than other nutrients. Within 6 h, 100% of settleable solids, 88% of total suspended solids, 71% of volatile solids, 63% of biochemical oxygen demand (BOD), 31% of total nitrogen and 55% of total phosphorus had sedimented from the final 20 cm of effluent. For the total pond this represented 61% settleable solids, 40% total suspended solids, 24% total volatile solids, 12% BOD, 7% total nitrogen, and 14% total phosphorus. Of the total amount removed during settling, 61% of settleable solids, between 18 and 26% of BOD, nitrogen and phosphorus, and between 34 and 45% volatile and suspended solids were found in the final 20 cm of discharge (16% of pond volume). A simple treatment of pond effluents at harvest can be effected by shunting the last 10–20% of discharge through a settling pond with no more than 6-h of residence.

Higher minimum dissolved oxygen concentrations increase penaeid shrimp yields in earthen ponds

Abstract Nine 0.11-ha earthen ponds were stocked on 15 May 1997 with Litopenaeus vannamei and L. stylirostris postlarvae in similar proportions at a total density of 33 animals/m 2 . Ponds were equipped with automated temperature and dissolved oxygen (DO) concentration data acquisition devices that sampled ponds every 30 min. Aspirator-pump aerators (0.75 kW) were automatically activated when DO fell to 65% (4.6 mg/l at 29°C and 15 ppt salinity), 40% (2.8 mg/l at 29°C and 15 ppt), or 15% (1.1 mg/l at 29°C and 15 ppt) of saturation. Mean shrimp yield, survival of both species, and profitability increased linearly as minimum DO concentration increased from 15% to 65% of saturation ( P P >0.05).

Influence of salinity and temperature on molting and survival of the Australian freshwater crayfish (Cherax tenuimanus)

Abstract The largest freshwater crayfish in the world are found in Australia. Cherax tenuimanus, or marron, is one of these large freshwater crustaceans which has attracted considerable interest as a potential aquaculture species during the past few years. Experiments to assess the suitability of marron for culture in the Southeastern United States began at Auburn University in 1986. A 6-week bioassay was used to evaluate the effects of three temperature ranges (17 ± 1 °C, 24 ± 1 °C and 30 ± 1 °C) and three levels of salinity (0, 50 and 100 mg/l NaCl) on marron survival and molting. As temperature increased molting frequency increased but survival decreased. Salinity had no effect on number of molts, but it had a positive effect on molting success and survival. Temperatures of 25 °C and less and salinity levels of at least 100 mg/l were found to provide the best survival. Because of a need for cool temperatures and low levels of salinity, limited areas in the Southeastern United States will be suitable for marron culture.

Forage-Based Feeding in Commercial Red Claw Ponds in Ecuador

Abstract Red claw crayfish, Cherax quadricarinatus, are perhaps the first tropical species of crayfish to be cultured commercially. Culture traits and high market value could allow semi-intensive culture. Feeding strategies used in extensive crayfish ponds in temperate climates may not be the most appropriate for semi-intensive culture systems where year-round growth is possible. The following study was conducted to evaluate differences between using a pellet-based system versus a pellet-plus-forage-based system. The study was conducted in 14 0.3-ha ponds on a commercial farm in Ecuador. Juvenile red claw (1-2 g) were stocked into all ponds at a rate of 4/m2. All ponds received pelleted shrimp rations at a rate of 3% per day. Seven ponds also received dried hay at a rate of 100 kg/ha/mo during the 3-month study. At harvest, red claw weights were similar (30-34 g), but survivals were significantly higher in ponds receiving pellets and hay (65%) than in ponds receiving pellets only (50%). Yields in pellet-fed ponds averaged 594 kg/ha, while red claw receiving pellets plus forage averaged 889 kg/ha. The addition of dried forage was thought to provide a larger variety of natural food organisms throughout a greater area of the pond bottom and provided additional substrate for dispersal and hiding. Addition of grasses from outside the pond is recommended over production of grasses grown within the pond.

A Preliminary Assessment of Growth, Survival, Yield, and Economic Return of Australian Red Claw Crayfish, Cherax quadricarinatus, Stocked at Three Densities in Earthen Ponds in a Cool, Temperate Climate

Abstract Juvenile (mean weight 8.1 g) Australian red claw crayfish, Cherax quadricarinatus, were stocked in July at three rates of 12,000/ha, 18,000/ha, and 24,000/ha into two, 0.02-ha earthen ponds in a cool temperature region of the United States (Kentucky) and grown for 70 days. Red claw were fed a pelleted marine shrimp diet twice daily. Ponds had continual aeration provided. Dissolved oxygen and temperature were measured twice daily (0900 and 1530 hours); total ammonia nitrogen (TAN), nitrite, and alkalinity were measured twice weekly; and pH was measured daily. At harvest, there were no significant (P > 0.05) differences in final individual weight, percentage weight gain, specific growth rate, feed conversion ratio, percentage survival, yield, and economic return among all treatments and averaged 58.4 g, 805%, 3.04%/ day, 7.47,42.7%, 461 kg/ha, and -

Growth Characteristics of the Australian Redclaw Crayfish, Cherax quadricarinatus, Cultured in an Indoor Recirculating System

2659/ha, respectively. There were no significant (P > 0.05) differences in the percentage of males and females harvested from the ponds among any stocking rate with males comprising 48.2% and females comprising 51.8%. Final individual weight of males and females was not significantly (P > 0.05) different among all treatments. These data indicate that there is no advantage to stocking red claw at rates below 24,000/ha in terms of growth, survival, yield, and economic return and that red claw can grow to marketable size in a cooler temperate region of the United States with a short (<110 days) growing season by stocking a larger-size (8 g) red claw.

Growth, Processing Measurements, Tail Meat Yield, and Tail Meat Proximate Composition of Male and Female Australian Red Claw Crayfish, Cherax quadricarinatus, Stocked into Earthen Ponds

Abstract The redclaw crayfish has been cultured in ponds since about 1990. As interest in redclaw has expanded, some culturists have begun to ask about culture potential in areas where pond culture may not be feasible. This study was conducted to determine growth characteristics of redclaw crayfish in an indoor, closed-system culture unit. Redclaw crayfish of two initial sizes, small (0.3±0.1 g) and medium (6.9±2.9 g) were cultured in tanks (1 m2) for five months. Temperature was maintained at 29±1.0°C, and the photoperiod was set at a 12:12 light:dark cycle. Survivals ranged from 65% to 70%. Final mean weights for the two size groups were 5.0 g and 29.0 g, respectively. Redclaw crayfish growth was much lower in this study than has been routinely reported for redclaw crayfish growth in outdoor ponds but not much different from what others have reported for other crayfish species cultured in indoor tanks. Factors that might cause the reduced growth include inadequate diet, density effects, and pheromones.