Ecological studies, in L. Barombi Mbo 100
L. Chilwa 99
in exotic communities 101-2
Kenya rift soda lakes 100-1
L. Kotto 100
L. Malawi 97-9
Pangani R. system 97
L. Victoria 91-3
in West African coastal lagoons 101
in West African crater lakes 99-100
Ecology, and distribution of tilapias
15-59
future studies of tilapia outlined 58
of tilapias in natural communities
83-114
of tilapias in L. Victoria 91-3
of tilapias in the Zambezi system 93-6
Ecuador, introductions 28
Edinburgh prison, hatchery work 328
Edwardsiella tarda, and haemorrhagic
septicaemia 255
Effects of fishing, on S. niloticus in
L. George 90
Efficiency of assimilation 150-2
in T. rendalli 169
Effluents, and cage culture experiments
207,218
research requirements to assess
environmental impact 358
Egg quality, discussed 139
Egg size, in dwarf populations 110
species specific 110
Eggs, development characteristics 48
green in T. zillii 5
ovoid in tilapias 132
size and parental care patterns 132
sticky substance in substrate spawners
132
yellow in T. rendalli 5
Eggs and larvae, in diet 144
El Salvador, introductions 28-30
Electropherograms, S, niloticus, S. aureus,
and hybrids 271~2,274
Electrophoretic methods, not yet suffi-
ciently developed to select pure
strains 282
Elops hawaiiensis, predator on young
tilapias 313
Embryonic period, defined 64
Energy cost of feeding, in T. rendalli
169-70
Environmental constraints, to cage
culture 237-8
Environmental factors, regulation of
reproductive activity 1334
in relation to maturation and spawn-
ing 337
Environmental physiology 119-28
Enzymes, use as serum markers 2734
Equipment, research requirements for
integrated systems 357
Ergasilus spp., parasitic copep~ds 2534
Escapes, following introductions 24
Esterase isoenzymes, use as serum
markers 270
Estradiol, in ovary of S. aureus 138
Estrone, and sex reversal 311-2
Estuaries, distribution of S. mossam-
bicus 52
as tilapia habitats 31
Ethynylestradiol, and sex reversal 311-2
Europe, introductions 29-31
Euryhaline species, wide distribution 20
T. guineensis 5
Eurythermal species 37-8
Eutrophic lakes, used for extensive cage
culture 216
Evolution, major importance of hetero-
ekrony 66
Excessive fertilizing of ponds, and
haemorrhagic septicaemia 255
Extensive cage culture 216-20
defined 216
experiments with S. mossambicus in
Laguna de Bay 218
Exotic communities, ecological studies
101-2
Eye flukes, and blindness in tilapias 252Facilities, research requirements for inte-
grated farming systems 357
Fat, and condition factor 163
see also Lipid
FCR, see Feed conversion ratio
Feces, relative energy content greater
than food in T. rendalli 169
Fecundity, and abundance 110
considerable individual variation 326
defined 318
factors affecting 318
and feeding 318
fry production and spawning frequency
discussed 3289
in interspecific spawnings 322,324