Author
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Mitchell, Andrew |
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BRANDT, THOMAS - NAT FISH HATCHERY |
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Submitted to: World Aquaculture Society Meeting
Publication Type: Abstract Only Publication Acceptance Date: 2/19/2003 Publication Date: 2/19/2003 Citation: MITCHELL, A.J., BRANDT, T.M. TEMPERATURE TOLERANCE OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE). WORLD AQUACULTURE SOCIETY MEETING. 2003. p.192. Interpretive Summary: Technical Abstract: The red-rimmed melania Melanoides tuberculata is an exotic aquatic snail of the family Thiaridae that is spreading across the southern United States and in geothermal waters in several midwestern and northwestern states. In addition to its potential to displace native mollusks it is known to harbor several parasites including Centrocestus formosanus, a gill trematode that causes serious infections in cultured and wild fish stocks. The red-rimmed melania is quite resistant to drying and to a number of molluscicides and disinfectants that are used to prevent its spread. There is little specific information on the temperature tolerance of M. tuberculata. Information on its tolerance to cool temperatures would allow an accurate prediction of its ability to spread from its current known locations. Information on its tolerance to warmer temperatures would provide knowledge needed for the heat disinfection of nets and equipment contaminated with these snails and thereby prevent their spread to uncontaminated waters. Cold tolerant tests were carried out in incubation chambers set at 5, 7, 9, 11, 13, 15, and 17°C. Ten snails (15 to 25 mm) were placed into 4 L jars with 2 L of aerated water and were exposed to each temperature for various periods of time. Exposure times were ½, 1, 2, 4, 8, 12, 16, 20, 24, and 28 d. Controls for each test were run similarly, but at 20°C. After exposure, all snails were placed at 20°C for 2 d and then examined for viability. Heat tolerance tests were carried out in a heat bath set at 40, 45, or 50°C. Ten snails (10 to 20 mm) were dipped in the bath at one of the given temperatures for exposures times of ¼, ½, 1, 2, 4, 8, 10, 16, 32, or 64 min. Preliminary information indicates that M. tuberculata is killed by exposure to 5°C for 24 h and 9°C for 96 h, and some mortality is observed when exposed to 15°C for more than 12 d. All 10 to 20 mm snails died when exposed to 50°C for 1 m and 45°C for 10 m. Snails Ê30 mm required 2 min and longer to kill at 50°C. Information will be provided for the determination of the 24, 48, and 96 h temperature tolerance limits that will kill 50% of the snails and specific information will be given on the effects of marginal temperatures (13 to 17°C) on the snails for up to 28 d. Temperatures and exposure times required for the disinfection of various sizes of the snails will also be given. |
