By-catch begone: changes in the philosophy of fishing technology

Since humans began fishing (at least 90 000 years ago), fishing technology has developed with the objective of trying to catch the greatest quantities of fish possible, of an ever-increasing variety. Fishing technology has evolved from simple harpoons and hooks to the industrial factory trawlers of the 20th century. After millennia of assuming that seafood resources are inexhaustible, and centuries of somewhat muted concerns that advanced fishing technologies may have detrimental impacts on stocks and ecosystems, the last century has seen advances in fishing technology blamed as a major cause of the current over-exploitation of fish stocks. It has mainly been during the last few decades that fishing technologists have begun to focus on more conservation-orientated goals. This occurred initially in response to concerns over the by-catch of charismatic species (like dolphins in tuna purse-seines), but quickly broadened to address concerns over the discarding of not-so-charismatic species (like juvenile fish killed by shrimp trawling). To ameliorate these issues, technologists and commercial fishers successfully developed various innovative gear-based and operational solutions. The steps involved in successfully reducing by-catches have tended to follow a certain incremental framework involving identification of problems using observer programmes, developing technological solution to these problems, experimentally testing these solutions, implementing these solutions throughout industry and finally gaining acceptance of the solutions from concerned interest groups. Most recently public concern has broadened once again from by-catch issues to encompass a much wider context involving the impacts of fishing on entire ecosystems, i.e. the impacts of fishing on all species affected – not just those species caught, retained or discarded. As a consequence, there have been many calls for ecosystem-based fisheries management to ensure that fisheries operate under the principles of ecologically sustainable development. Scientists are gradually filling the gaps in our knowledge about how fishing affects whole ecosystems but, because of the scales and complexities involved, such studies are usually difficult, expensive and of long duration. While this descriptive work is difficult, finding solutions to any identified problem is an even greater challenge, particularly for fishing technologists. The easiest solutions to such problems involve rather draconian management strategies like closures. A less extreme alternative involves the development of new technologies that reduce the impacts of fishing on ecosystems – in a similar way as that done to reduce by-catch problems. Innovations like altering ground-chains, footropes, sweeps and trawl doors have been suggested as possible ways to ameliorate the environmental damage done by trawling, but such research is still very much in its infancy. Nevertheless, the recent history of fishing technology is chequered with successfully meeting such challenges, giving one confidence that solutions to such issues may eventually be developed. Integral to the success of any solutions that strive towards the goal of perfect selectivity, however, is a corresponding improvement in the adoption of these methods by fishers. As our framework shows, this is best achieved by involving fishers in all aspects of the work.