APPENDIX A5.1

 

GLOSSARY FOR FISHERIES IMPACT ASSESSMENT

 

 

Ardeid                          Species of birds of the Family Ardeidae, consisting of mainly herons, egrets and bitterns.

 

Bund                            Embankment around the perimeter of the pond.

 

Detritus                        Material produced by disintegration of plants and animals bodies following death and decomposition.  Also refers to materials formed by erosion, e.g. sand, gravel and silt.

 

Draining                        Management practice employed in aquaculture that involves draining water out of ponds using either a pump or sluice gate to assist in aggregating fish in high densities to facilitate harvesting.

 

Ecological Value           The contribution of a habitat in sustaining the wildlife communities and essential ecological processes of a wider ecosystem.

 

Fish-cum-Duck            The simultaneous raising of carp integrated with duck farming. This integrated approach utilises the manure and excreta originated from the ducks as organic fertilisers to enhance the productivity of the systems.

 

Food web                    The inter-connected chains of food intake within an ecosystem.

 

Hetertrophic                 Organisms that obtain nourishment  from organic substances.

 

Monoculture                 An aquaculture system where one species of fish is reared in each pond, typical species include Catfish, Seabass and Snake head.

 

Phytoplankton              Microscopic marine or fresh water plants (phytoplankton) that drift within the water column, and undertake primary productivity in aquatic ecosystems.

 

Plankton                       Microscopic marine or fresh water plants (phytoplankton) or animals (zooplankton) that drift within the water column.

 

Polyculture                   Entails the rearing of more than one species within a single pond at one time. This aquaculture techniques contributes to 96.5% of the total area of active fish ponds in Hong Kong during 1994.

 

Species                        Biologically species is  a group of organisms that can potentially interbreed to produce fertile offspring.  In practice, species may be recognised by their similar morphology.

 

Tilapia                          An omnivorous fish that consumes detritus and plankton, reared as a commercial species and as considered as a trash fish.

 

Trash Fish                    Fish that inhabit commercial fish ponds but are not of commercial value, typical species include: Mosquito Fish, Pawn, Tilapia.

 

Trophic                        Pertaining to the trophic level of food webs.

 

 

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