A workable solution?

As hundreds of dolphins and porpoises continue to be caught in the UK every year, we ultimately need to take a precautionary, ecosystem based approach to the problem.

We need to develop a better understanding of populations, habitat use and feeding behaviour and to understand how and why dolphins and porpoises get caught in fishing nets. Scientific research has demonstrated that they are capable of detecting the presence of a net in the water - so what goes wrong - why do they get caught? If we knew this we would be able to develop methods and/or devices to prevent their capture. Until then however we need to take action, we need to prevent any more needless deaths.

Pingers, which have become mandatory, but are yet to be implemented in UK fisheries, are not the long term solution to the problem. There are a number of concerns over the effects which may be initiated by the pinger. Producing an aversive noise, scientists are concerned that the pinger, when deployed on nets, in areas of intensive fishing effort, may actually deter porpoises from utilising certain areas, which may serve as important feeding grounds for them. This can lead to population redistribution - potentially in suboptimal habitat. Additionally, porpoises may actually get used to the noise, rendering the pinger ineffective, or worse still associate the sound with the presence of food and act as a 'dinner bell'. The long term thinking was that by implementing pingers there was a short term solution to the problem to allow other mitigation measures to be trialled which may have less obtrusive effects on the populations. Yet four years on from the Regulation coming into force we are still waiting to see pingers deployed on fishing nets.

Other solutions to cetacean bycatch include a variety of fishery management options, including time/area restrictions, effort reduction, alternative gear types and fishery closures.

In fisheries with a significant level of bycatch, there is a direct correlation between fishing effort and cetacean bycatch. Therefore, for these fisheries, any measure to reduce fishing effort would lead to a reduction in bycatch. There are a number of ways in which fishing effort could be reduced - reduction in soak time and/or net lengths, time and area fishery closures and days at sea limitations. The method required to reduce bycatch would depend on the nature of the fishery and these forms of fishery management techniques could be used independently to reduce bycatch, or be a part of a wider management strategy limiting catches of fish.

It is emphasised that each operational interaction between small cetaceans and commercial fishing gear is likely to require a solution specific to that combination of animals and gear. In many cases there is also a need to ensure that any closures are enshrined in legislation and not reliant of voluntary measures, which have been shown to have limited success in the past. Any time-area closure system must be enforced to ensure compliance.

Alternative methods means that the type of fishing gear used or fishery practice employed is altered to reduce cetacean bycatch. Such modifications could include, for example, changes in net type, acoustically reflective nets, floating head ropes and for pelagic trawling - separator grids.

The measures examined here are by no means an exhaustive list of those available to assist in the mitigation of cetacean bycatch. Other available tools include management, mitigation or recovery plans; the use of education, training and market measures and incentive programs to encourage certain behaviour and the benefits of management organisations. Other tools or necessary elements include consultative decision making, data collection and monitoring.

Recommendations