Bilharzia, molluscan vectors in tilapia
ponds 57
Binders, for use in pellets 345
Biological control, and introductions 24
vegetation and S. aureus 29
Biomass, in littoral zone of L. Kainji 51
Birds, and digenean infections in fish 252
excluded fiom broodstock tanks 285
predators in L. Nakuru 101
predators on tilapias 110
protection against in cage culture 209
Bitter Lakes (Egypt), high salinity 38
S. galilaeus 38
S. niloticus 38
Black spots, caused by neascus metacer-
cariae 251
Blindness, and eye flukes 252
Bodonid parasites 249
Bolivia, introductions 30
Brackish habitats 38
Branchiomyces spp., can be significant
cause of mortality 256
Brazil, all-male hybrid production 284-89,
291-6
introductions 30, 57
Breeding, factors affecting periodicity
44-6
length of season 45
periodicity in various species sum-
marized 45-6
and rainy season 44-6
and temperature 44-5
Breeding arenas, of mouthbrooders 47
Breeding behavior 43-50
and aquaculture 49-50
guarding the young 48
notable studies 434
S. galilaeus 8
S. melanotheron 7
S. mossambicus in L. Sibaya 96
spawning grounds 46-7
territoriality 48-9
Breeding seasons, staggered in L. Malawi
98
extended in L. Mariout 104
Brewery waste, used in pond culture 199
and semi-intensive cage culture 223-4
Brooding areas, of mouthbrooders 47
Brooding efficiency, and size of fish 111
Broods, number varies 110
Broodstock, genotype cannot yet be
determined routinely on a
commercial scale 282
nutritional requirements 346
techniques to protect 285
Broodstock control, use of genetic
markers 269-77Cage culture 205-46
adequate feeding essential 212
advantages 236-7
behavior of parasites discussed 246
cage construction 209
cage prices 210-11
cage size and production discussed
245
cage tppe and size 208-9
damage and losses caused by pre-
dators 238
defined 205
development limited by supply of
seed 212
disease aspects 238-9
environmental constraints 237-8
experiments with salmonids in
Scottish lochs discussed 246
extensive cage culture 216-20
factors influencing production 213
feed conversion ratio and cage size 208
fingerling production 215
food wastage 345
fouling by algae discussed 245
fry production 213-6
future prospects bright 207
growth and production 212-3
inputs as constraints 238
intensive cage culture 223-6
management of stocks 211-2
materials for cages 210
myxosporidians kill S. niloticus 262
poaching and security 239
policy and planning needs 239
potential of major tilapia species 240-5
production 213
protection of majdr tilapia species
240-5
production 213
protection against birds 209
protection against poachers 209
research needs identified 23940
seed production 213-6
semi-intensive cage culture 220-4
site selection 211
species used 206-7
technological aspects 207-11
working life of cages 210
worldwide activities summarized 206