Biomanipulation is the deliberate alteration of an

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

by adding or removing species, especially predators.

Aquatic ecosystems

Changing the fish population of bodies of water as a part of

watershed management Watershed management is the study of the relevant characteristics of a watershed aimed at the sustainable distribution of its resources and the process of creating and implementing plans, programs and projects to sustain and enhance watershed f ...

can facilitate desirable changes in

aquatic ecosystems An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environm ...

suffering from

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

characterized by domination by

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater Aquatic ecosystem, ecosystems. The name comes from the Greek language, Greek words (), meaning 'plant', and (), mea ...

aiding

ecosystem restoration Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from conservation in that it attempts to retroactively repair ...

, an application of

restoration ecology Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from Conservation movement, conservation in that it attempts t ...

. In ponds or lakes alternative stable conditions, one with high algae populations, little other plant life, and turbid water, another with low algae populations, a diverse plant population, and clear water, may exist. In addition to prevention of excess nutrients such as phosphorus and nitrates, removal of certain fish species adapted to turbid water may facilitate change from one steady state to the other, an application of

dynamical systems theory Dynamical systems theory is an area of mathematics used to describe the behavior of complex systems, complex dynamical systems, usually by employing differential equations by nature of the ergodic theory, ergodicity of dynamic systems. When differ ...

. Fish species may be removed by means of poison, harvesting, or introduction of predatory species. As a different fish community will result from the process it will affect recreational and commercial fishermen whose cooperation or opposition is important. Limnaea peregra var

Lake Zwemlust, a hypertrophic pond used as a swimming pool in The Netherlands with an area of 1.5 hectares and an average depth of 1.5 meters, was treated in March 1987. The initial Secchi disk transparency was only 0.3 meters, less than the 1 meter maximum permitted for swimming pools in The Netherlands. In the first summer Secchi disk transparency increased to at least 2.5 meters, the maximum depth of the lake. The lake was drained and 1,500 kilograms of planktivorous and benthivorous fish such as

common bream The common bream (''Abramis brama''), also known as the freshwater bream, bream, bronze bream, carp bream or sweaty bream, is a European species of freshwater fish in the family Leuciscidae. It is now considered to be the monotypic, only speci ...

were removed by seining and

electrofishing Electrofishing is a fishing technique that uses direct current electricity flowing between a submerged cathode and anode. This affects the movements of nearby fish so that they swim toward the anode, where they can be caught or stunned.

. The pond was stocked with 1500

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). T ...

fingerlings and some mature

rudd ''Scardinius'' is a genus of freshwater ray-finned fishes belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related species. The fishes in this genus are commonly called rudds. Locally, the name "rudd" without ...

whose offspring served as food for the pike.

Willow Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

branches,

nuphar lutea ''Nuphar lutea'', the yellow water-lily, brandy-bottle, or spadderdock, is an aquatic plant of the family Nymphaeaceae, native to northern temperate and some subtropical regions of Europe, northwest Africa, and western Asia. This species was us ...

roots, and starts of

Chara globularis ''Chara globularis'' is a species of charophyte green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains ...

were added as vegetation and shelter. Expenses were met by the local water authority which was compensated by increased patronage by swimmers. In the summer of the second year, 1988, there was considerable plant growth and, possibly due to lack of predation by carp or minnows, an explosion in the number of

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

s, including

Radix peregra ''Peregriana peregra'' is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod in the family Lymnaeidae, the pond snails. Distribution and habitat This small pond snail is found in Europe, Newfoundland and northern Asia. ...

var. ovata a host of

Trichobilharzia ocellata ''Trichobilharzia'' is a genus of trematodes in the family Schistosomatidae Schistosomatidae is a family of digenetic trematodes with complex parasitic life cycles. Immature developmental stages of schistosomes are found in molluscs and ad ...

the cause of schistosome dermatitis,

swimmer's itch Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the Human skin, skin of humans that have been infected by water-borne schistosomatidae, schistosomes, a type of Trematoda, fl ...

. In addition to grazing by

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

the lush growth of

macrophyte Aquatic plants, also referred to as hydrophytes, are vascular plants and non-vascular plants that have adapted to live in aquatic environments ( saltwater or freshwater). In lakes, rivers and wetlands, aquatic vegetations provide cover for aquat ...

s removed sufficient nutrients from the water to prevent

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

Notes

External links and further reading

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