Shellfish - Drought Conditions Raise Problems In Gulf Coast Oyster Industry




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Dr. Sammy Ray, Professor Emeritus, Texas A&M University - Galveston. Because of the drying and warming conditions in three consecutive years. The abnormally warm winter, coupled with high salinities, in Galveston Bay from September 1999 through April 2000 has caused a heavy carry-over of 'Dermo,' a microorganism parasite (Perkinsus marinus) into spring. In the more saline portions of Galveston Bay system such as West Bay had salinities had reached 40 parts per thousand (ppt) in August. The average Gulf salinity is about 35 ppt. In such areas, the oysters have suffered heavy mortality and market-sized oysters are difficult to find. Also in such areas as West Bay and areas in west Galveston Bay (April Fool Reef), the shells of oysters are so heavily infested with boring sponge (Cliona), the shells are heavily eroded and damaged by this shell pest. Dr. Ray reported that the high 'Dermo' levels were now found in sub-market (less than 3' long) oysters. Many will die before reaching market size (3'). The high salinities in normally low salinity areas as Trinity Bay have resulted in significant populations of market oysters. Fortunately, according to Dr. Ray, upper Galveston Bay has received heavy fresh water inflow in June and July through Trinity River discharge. The timing of this fresh water has been very helpful. However, if not enough fresh water is received to reduce the salinity in the major oyster producing areas of the Galveston Bay system, it is feared that the Galveston Bay oyster production will be severely affected this and next year, if drought conditions continue to persist




ASW,USA,Texas,Galveston Bay, Droughts, Fisheries, O 5060 Aquaculture, Oyster culture, Oysters, parasites, Perkinsus marinus, population dynamics, Q1 01484 Species interactions: parasites and diseases, Q1 01583 Shellfish culture, Q3 01583 Shellfish culture, Salinity, Salinity effects, Survival, USA, winter, Yield