Researchers have conducted a number of studies on the effect of 'pingers', small devices that act as acoustic alarms for small cetaceans. This means that they move away from the boat and avoid being trapped in the nets. It must be emphasised that this strategy is by no means perfect - according to this study: Using pingers to reduce bycatch of small cetaceans in Peru's small-scale driftnet fishery, the pingers only halve the number of small cetaceans getting caught in the nets, so aren't as effective as one would hope, but it is still a vast improvement on current numbers. Furthermore, the pingers do not stop the cetaceans from returning to that area to feed once the boats have passed. This could also be beneficial for fishermen because bycatch results in damaged nets. For now, the pingers are outlawed on the grounds that they 'disturb a protected species by putting noise into the environment'. The pingers cost £250, which in the long term, can be a good investment. Currently, pingers are illegal in the UK for use by small boats, but conservationists hope they will be legalised in order to slow down the downwards trend within porpoise populations. Under Eu rules however, pingers are mandatory for vessels more than 12 metres in length. What do you think?