A drying floodplain lake
Fishing is among the numerous uses for floodplains defined as "areas of low-lying land that are subject to inundation by the lateral overflow of waters from rivers or lakes with which they are associated. The floods further bring about such changes in the physico-chemical environment that biota react by morphological, anatomical, physiological or ecological adaptations, or by change in community structure."
The fish communities of floodplain rivers have been the subject of special considerations as they are particularly vulnerable to changes in water quality and quantity induced by human activities.
The seasonal flooding of river floodplains, along with their lakes, is among the most important factors determining river fish production. The timing and duration of flooding are highly variable, greatly affecting growth and survival of fish. When inundated, the plain contains a rich mosaic of habitats that provide shelter, breeding, nursery and feeding sites for a variety of fish species.
Floodplain capture fisheries are mostly seasonal. For example in Bangladesh, fishers target fish when these enter re-flooded plains at the beginning of floods to spawn. After the end of the flood season and the retreat of floodwaters, residual waters on floodplains are heavily fished. The fishing is usually indiscriminate, with the removal of all fish. Floodplains of African rivers support similar types of fisheries.
A river floodplain
Many people live along and around rivers and floodplains. Fish and aquatic products provide essential nutrition and buffer food insecurity. In many areas of the world floodplain fisheries have maintained the same level of catch despite the increasing fishing pressure on fish stocks. Initially this reduced the average age of stocks fished and increased the efficiency of utilization of their food. Acceleration in growth rate and reduction in the size of maturation of the exploited species has also been common. Subsequently, larger, slower-growing, longer-lived species are apt to be replaced with smaller species of a higher turnover rate. The ability of floodplains to act as sink for carbon and nutrients is conducive to maintaining the stability of this ecosystem.
Restoration of fish stocks is necessary when the tolerance of floodplains to environmental degradation is exceeded -- a case often accompanied by high fishing pressure and by the introduction of mitigating measures, such as habitat and fish stocks enhancements.