Cardigan Bay is one of the most abundant sealife coastline habitats in Europe. Cardigan Bay Marine Wildlife Centre (CBMWC) have identified 300 individual dolphins, seals, basking sharks, minke whales and even orcas that use the Welsh beauty spot, and evidence from researchers now suggest that the dolphins use a particular spot to train their pups how to hunt.
The Quay Fresh and Frozen Foods plant in New Quay, Ceredigion, regularly conducts licensed discharges of whelk waste and shells. While previous research had suggested that the discharges might have been driving dolphins away because the piles of whelk shells were changing the nature of the seabed, new findings suggest the opposite.
Third year Swansea University marine biology student Jodie Denton focussed on dolphin numbers in the area for her dissertation project, aiming to determine what impact the factory had on the abundance of bottlenose dolphins. Stationing herself near the factory, Denton scanned the water for four hours from 5am, every day for five weeks, counting how may dolphins turned up. She concludes that more dolphins were present when the factory was open, and even more when it was discharging the waste. Denton also claims that the longer the factory stayed open, the more dolphins turned up.
This increase in dolphin numbers is due to the surplus of prey in area, which is directly caused by the factory’s discharges. Not only is there a nice, easy meal for the dolphins to feed on from the whelk waste itself, but the smell of the whelk waste is likely to be detected by fish such as mullet, bass and mackerel miles down the bay. CBMWC manager Steve Hartley states that the discharges attract “a variety of fish to feed on these bits and pieces and the dolphins come in to feed on the fish that are feeding on this waste.”
This abundance of prey close to the plant allows dolphin pups to try out their fish hunting skills. Hartley says: “Wherever the mother is, she’ll be teaching her pup social and feeding strategies in the same way a human mother would teach her children how to survive day to day” and the “the relatively shallow water [by the plant] means that the youngsters, which cannot dive deeply, can have a stab at fishing for themselves”.