Modelling interactions between top predators and fishing vessels: implications for fisheries management in a wider ecosystem

We showed that it is possible to construct a complex, dynamic, spatially-explicit model of the interactions between seals and fishers that are mediated by their shared prey. This model could be used as the basis for an Ecosystem Approach to Fisheries. Predictions from the model were consistent with available data on seal diet and landings of cod, haddock and whiting at Peterhead. We used the model to investigate the effect of excluding fishing vessels targeting these species from an area known to be used by both seals and fishers. This had no effect on the total energy intake of seals, but did have a small effect on commercial landings.

Fishers often complain that seals eat commercially valuable fish and that this reduces their catches and income. Conservationist are equally concerned that commercial fishing depletes fish stocks, and that this could have a negative effect on other wildlife. We developed realistic mathematical models of these interactions and found that banning fishing in Marine Protected Areas would have very little effect on either seals or commercial landings of fish.

We can construct realistic spatially-explicit models of the interactions between seals and fishers.

These models can provide valuable insights into the likely effects of banning fishing in Marine Protected Areas or Special Areas of for Conservation on fishers and predators.