Assessment of management practices and occurrence of mycobacterium marinum infection in selected milkfish (Chanos Chanos) farms in Zanzibar, Tanzania
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Date
2017
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Publisher
Sokoine University of Agriculture
Abstract
Milkfish farming in Zanzibar is at infancy stage, practiced at small-scale levels and
faces a number of constraints including fish health problems. The purpose of this
study was to assess the milkfish farming practices and possibilities for occurrence of
Mycobacterium marinum infection in selected milkfish farms in Zanzibar, Tanzania.
A questionnaire survey was administered to 24 milkfish farmers to acquire
information on general management system, fish health and related problems. Pond
physicochemical characteristics were assessed using standard procedures. Pond water
(24), sediments (24) and fish (240) samples were collected for laboratory analysis
ofw21 M. marinum using standard procedures. Most (92%) of farmers were
smallholder with backyard ponds. About (91.7%) of the ponds were of earthen type
adopted from salt pans and practiced polyculture (Chanos chanos + Mugil cephalus)
technique. Fingerlings were obtained from the sea, some farmers did not feed their
fish and there was no routine water exchange in ponds. Likewise, fish farmers were
not aware about fish health related issues and fish mortalities were reported. Water
temperature ranged between 29.3 οC to 37.1 οC varying significantly (P<0.05)
between ponds. Dissolved oxygen ranged between 1.9 and 6.1 mg/l while the mean
pH was 7.5 ± 0.5 and 8.2 ± 0.2. All sampled fish were apparently healthy. A total of
110 samples had bacterial growths on Lowenstein- Jensen media but only 12 (4.2%)
were AFB positive. No any isolate was found to have DNA band size of 1030 bp for
Mycobacteria which implied that they were not Mycobacterium. It is concluded that
fish pond management practices was poor and farmers lack of knowledge on good
management practices for optimal milkfish production. Health related problems exist
in fish ponds but not mycobacteriosis. Education on fish diseases should be provided
to farmers and researches on fish diseases including mycobacteriosis are
recommended.
Description
M.SC. Dissertation
Keywords
Management practices, Chanos Chanos, Zanzibar, Tanzania, Mycobacterium infection, Milkfish farming, Fish health