All types of fishing operations produce adverse impacts on the marine ecosystem to a greater or lesser extent. Harmful effects range from subtle and difficult to quantify shifts in trophic systems resulting from the discarding of bycatch, to rigorous and highly politically charged effects like the incidental killing of cetaceans by drift nets. In terms of the persistence of the impact, this may range from minor ruts on sandy substrates caused by light trawling gear that may smooth over with the next tide, to long lasting consequences like the long term recovery of dynamited coral reefs.

We attempt to review the possible detrimental ecological effects of some common fishing practices including bottom trawling, purse seining, dredging, longlining, drift net fishing, fry collection, dynamite fishing, and cyanide fishing. In addition, certain issues associated with commercial fishing such as discards, 'ghost fishing’ by lost gear, and changes in trophic structure of fish communities are discussed. Furthermore, relevant cessation and mitigation methods including technological advances, management measures, economic forces, and national and international legislation are provided.

The effectiveness of these methods and measures are highly dependent on the participation of the fishing community and industry, international co-operation, and effective enforcement. In future, fisheries should be managed and developed within the context of a precautionary principle, adaptive management strategy, and ecologically sustainable development.