水産および畜産生産

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Cool Water Off-flavor Algae and Water Quality in Four Arkansas Commercial Catfish Farms

Lin X* and Peter P

Catfish pond culture during the cool weather period of late fall, winter and early spring have experienced problems related to algal populations. Geosmin tainting by off-flavor cyanobacteria is more abundant at this time. Toxic algae episodes also appear to be more common during cool weather periods, including the devastating new golden algae (Pyrmesium parvum) HAB, in adjacent Texas and believed to have occurred in Arkansas. Water and phytoplankton samples were collected weekly at 0800-1000 from November to April for three consecutive years from 12 ponds at 4 commercial catfish farms located in the southeastern Arkansas. Oscillatoria chalybea was found from November- January at low levels and Pseudanabaena limnetica occurred from January-April. Results from multiple regression show that the values of the expected number of Anabaena circinalis is significantly associated with dissolved oxygen, pH, total ammonia nitrogen, nitrite nitrogen, green algae, Chlorophyll a and Pheophytin a and the expected number of Oscillatoria chalybea is associated with total ammonia nitrogen, un-ionized ammonia, Pheophytin a cyanobacteria, and diatoms, whereas the expected number of Pseudanabaena limnetica is linked to temperature, total ammonia nitrogen and un-ionized ammonia, respectively.