Probabilities of low nighttime temperatures during stocking and harvest seasons for inland shrimp culture

Authors: Green, Bartholomew - Bart; Popham, Thomas

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2007
Publication Date: 1/28/2008
Citation: Green, B.W., Popham, T.W. 2008. Probabilities of low nighttime temperatures during stocking and harvest seasons for inland shrimp culture. Journal of the World Aquaculture Society. 39:91-103.

Interpretive Summary: Interpretive Summary: Farmers who grow the Pacific white shrimp, a marine shrimp, in ponds filled with low-salinity water at inland sites across the southern US culture a tropical species in a temperate or sub-tropical climate. The growing season in ponds is limited to periods when water temperatures permit shrimp survival and growth. Low nighttime air temperatures associated with cold fronts, which can move in quickly and last for a number of days, can reduce pond water temperatures. While the lower lethal water temperature for the Pacific white shrimp is not known with certainty, 57 F appears to be a reasonable estimate. Cold fronts periodically move into the southern US during the spring and fall, and can remain in place for a number of days before moderating. One night with a minimum air temperature of 57 F or cooler may cool water in ponds or outdoor tanks sufficiently to kill the Pacific white shrimp. Three to five consecutive days of minimum air temperature 57 F or cooler would be expected to further exacerbate the decline in water temperature. We calculated from 74-100 year minimum air temperature datasets the probabilities of occurrence of minimum daily air temperatures less than or equal to 57 F for one, three, or five consecutive days for eight sites in the southern US where this shrimp is or could be grown in inland ponds. These probabilities can be used to guide pond management decisions at the beginning and end of the growing season when intrusion of cold fronts may cause pond water temperatures to drop to critical levels. The probability of one day, three consecutive days, or five consecutive days with a minimum air temperature 57 F or cooler is high (50%) from late-March through late-April at all sites except Arcadia, FL. Probabilities drop to 10% for the three scenarios by early-May to early-June. In the autumn, the 10% probability level is reached in early- to mid-September and the 50% probability level is reached by late-September to mid-October. Arcadia, FL, has the longest period with low probabilities of low minimum air temperatures and Pecos, TX, has the shortest.

Technical Abstract: Technical Abstract: The pacific white shrimp (Litopenaeus vannamei) is cultured in earthen ponds at inland sites across the southern US. The growing season in ponds is limited to periods when water temperatures permit shrimp survival and growth. Low nighttime air temperatures associated with cold fronts, which can move in quickly and last for a number of days, can reduce pond water temperatures. While the lower lethal temperature for L. vannamei is not known with certainty, 14 C appears to be a reasonable estimate. Probabilities of occurrence of minimum daily air temperatures less than or equal to 14 C for one, three, or five consecutive days were calculated from 74-100 year minimum air temperature datasets for eight sites in the southern US where L. vannamei is or could be grown in inland ponds. The probability of one day, three consecutive days, or five consecutive days with a minimum air temperature less than or equal to 14 C is high (50%) from late-March through late-April at all sites except Arcadia, FL. Probabilities drop to 10% for the three scenarios by early-May to early-June. In the autumn, the 10% probability level is reached in early- to mid-September and the 50% probability level is reached by late-September to mid-October. Arcadia, FL, has the longest period with low probabilities of low minimum air temperatures and Pecos, TX, has the shortest. The maximum pond water temperature from the previous afternoon and the minimum air temperature from that night predicted the minimum pond water temperature the following morning for Pine Bluff, AR. Multiple regression analysis yielded the following equation to predict minimum pond water temperature (R2=0.886): Tmin = 1.464 + 0.169Amin + 0.727Tmax, where Tmin = minimum daily pond water temperature (C), Amin = minimum air temperature (C) for the same day, and, Tmax = maximum pond water temperature (C) from the previous day.