Suitability studies of inland well waters for Litopenaeus vannamei culture

摘要

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(-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 144-1 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 PL10 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 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 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 SO4 and negatively correlated with a high concentration of iron.