Issue 16: Destructive fishing practices

Fishing has significant direct and indirect impacts on habitat, and on the diversity, structure and productivity of benthic communities. These effects are most readily identified and last longest in areas that experience infrequent natural disturbance, such as coral reefs and deep-water benthic communities. In areas such as shallow water sandbanks, where the substrate is frequently influenced by environmental incidents such as storms, the effects of fishing are less significant and tend to be short lived.

Harmful effects of fishing can include destruction of habitat and subsequent loss of biodiversity, shifts in community structure with a decrease in biomass and a change to dominance by scavengers. Effects can be drastic, highly visible and long-lasting, such as the use of dynamite on coral reefs, or can be more subtle and invisible such as shifts in community structure in deep water ecosystems. Examples of indirect effects of fishing gear include: increasing sediment load, deposition of silt and removal of herbivorous fish from coral reefs leading to a take-over of the reef by algae

Fishing methods that can be classified as destructive include such methods as the use of dynamite or poisons, particularly on coral reefs, beam trawling and dredging.

References

Kaiser, M.J. and de Groot, S.J. (eds)., 2000 The effects of fishing on non-target species and habitats: biological, conservation and socio-economic issues. Blackwell Science, Oxford. 399 pp.

Jennings, S. and Kaiser, MJ, 1998. Effects of fishing on Marine ecosystems. Advances in Marine Biology, Vol 34, 201 – 352.

Hall, S.J. 1999. The Effects of Fishing on Marine Ecosystems and Communities. Blackwell Science, Oxford.

GIWA definition

Destructive fishing practices are those that are deemed to produce significant harm to marine, lacustrine or coastal habitats and communities.

Environmental impacts

1. Changes in biological community structure due to overexploitation/depletion of one or more key species

2. Changes to habitat and community structure resulting from destructive fishing practices

3. Ecosystem degradation

Indicators

The following are environmental impact indicators for destructive fishing practices.

Select the environmental impact indicators that are relevant from the list below and input data into the appropriate indicator sheets.

Fisheries

Map and satellite derived

Biological

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