Ma. Thorburn, VARIABLES ASSOCIATED WITH THE USE OF CHEMOTHERAPEUTIC-AGENTS ON TROUTFARMS IN ONTARIO, CANADA, Preventive veterinary medicine, 24(1), 1995, pp. 1-14
This study investigated whether certain farm-level variables were rela
ted to the use of chemotherapeutic treatments by Ontario, Canada trout
producers, Several treatment outcomes were examined in each of two fi
sh-size categories (10 cm or less and over 10 cm), including: (1) the
likelihood of initiating any treatment; (2) the frequency of treatment
initiation; (3) the likelihood of using any preventive treatments; (4
) the likelihood of initiating more than half of all treatment regimen
s for preventive reasons. Data were obtained by personally interviewin
g 62 farmers who in total marketed 91% of the farmed trout produced in
Ontario in 1990. Producers with more years of fish farming experience
or those with no more than one full-time equivalent person working wi
th the fish were less likely to have initiated treatment in either siz
e category than were those with less experience or more workers. In ad
dition, farmers producing fewer fish or those running specialized hatc
heries or vertically integrated operations were less likely to have ev
er treated fish that were 10 cm or less in size than were those with l
arger farms or growout-only operations. Treatment frequency increased
significantly if farmers had used preventive treatments. Also, among f
armers who did treat 10 cm or smaller fish, those with more years of f
arming experience tended to initiate fewer treatments. Farmers with ha
tcheries or vertically integrated farms were less likely to have initi
ated any preventive treatments in 10 cm or smaller fish than were thos
e with growout-only operations, Members of the Ontario Aquaculture Ass
ociation were less likely than non-members to have initiated more than
half of their treatment regimens in 10 cm or smaller fish for prevent
ive reasons. Farmers who had lower water flows per 10 cm or over fish
tended to rely more heavily on preventive treatments in this size grou
p of fish than did those with higher flows per fish.