Amateur Fishing Threatening Rare Dolphin Population in New Zealand

Hector's dolphin is an endangered species of dolphins that's native to New Zealand and according o a new study, its population is declining due to amateur fishing in its habitat.

Akaroa harbor near Christchurch is a hotspot for tourists wanting to catch a glimpse of the dolphins or go swimming with them. However, in recent years fishing has led to many dolphins being caught in nylon fishing nets.

Hector's dolphins are the smallest and rarest dolphins in the world. The dolphin can fit in an average bathtub and has distinct black facial markings with a dorsal fin (fin on the back) resembling the ears of Mickey mouse. Only 55 of Maui's dolphins, a subspecies of the Hector's dolphin exist today. Hector's dolphins are only found on the western shores of New Zealand's North Island.

For the study, researchers placed three "T-POD" acoustic devices in the inner, middle and outer parts of the Akaroa Harbour. The devices picked-up the dolphins' echo in the region for over a year.

At the Akaroa Harbour, people are allowed to set-up fishing nets between 1 April and 30 September because dolphins are thought to be far away from the harbor during summer months. However, the new study shows that the dolphins stay close to the harbor, even during summer.

"Because Hector's dolphin echo-location clicks are very different from those of other dolphins in New Zealand, we can tune the T-PODs to detect them specifically," said Professor Steve Dawson, a dolphin expert from University of Otago said in a news release. 

Their study showed that the dolphins were present on 41 percent of the days in the recreational area in summer.

"This shows that dolphins use this area much more regularly that previously thought, and that the concession offered to amateur gillnetters is not safe for the dolphins," Dawson said in a news release.

The study shows that at times, the area marked for conservation of a species doesn't match its distribution which leaves many dolphins unprotected, experts said.

The study is published in the journal Endangered Species Research.