Limnology 160 Water quality 149 England 131 Fisheries 131 Management 123 Inland waters 103 Freshwater fish 75 Rivers 75 Ecology 52 Migratory species 51 Fishery management 50 Pollution 41 Fishery regulations 38 Fish catch statistics 36 Fishery data 35 River fisheries 33 Nature conservation 32 Environmental monitoring 28 Freshwater pollution 28 Salmon Action Plan 28 water quality 28 Spawning targets 26 Cornwall 25 Licensing 25 Salmon fisheries 25 Environment 21 Environmental assessment 21 Water management 21 Fishery Advisory Committee 20 Iran 16