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Use of Chemotherapeuties on Trout Farms in Ontario
Author(s) -
Thorburn Margaret A.,
Moccia Richard D.
Publication year - 1993
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1993)005<0085:uocotf>2.3.co;2
Subject(s) - trout , biology , fish farming , fish <actinopterygii> , prophylactic treatment , veterinary medicine , zoology , toxicology , fishery , aquaculture , medicine
A personal‐interview survey was conducted to determine the frequency of and reasons for chemotherapeutic treatments on Ontario trout farms during 1990. Sixty‐two farmers, producing 91 % of Ontario's farmed trout, participated in the survey. Farmers had most often received advice on treatments from other farmers. The number of treatment regimes administered during a production cycle ranged from zero (5% of farms) to more than nine; the median on user farms was 2.3 treatment regimes. Chloramine‐T and formalin were the most commonly used chemicals (they were used on 66 and 53% of the farms, respectively). Preventive treatments accounted for 67% of all treatment regime initiations; initial therapeutic treatments, primarily for gill diseases, accounted for 22% and repeat treatments accounted for 11%. At least some 2‐10‐cm fish were treated on most farms. Fish in increasingly larger size ranges were treated for therapeutic purposes on progressively fewer farms; prophylactic treatment, however, appeared to be independent of the size of treated fish. Farmers who used prophylactic treatments tended to treat fish much more frequently. There was, however, large variability among farms in the frequency of prophylactic treatment regimes, indicating that farm‐specific factors may strongly influence the perceived need for chemotherapeutic prophylaxis. The relatively common occurrence of treatment failure indicates that at least some therapeutic treatments may be applied incorrectly.