On today’s episode of Species Tuesday, we highlight the threatened Hector’s dolphin (Cephalorhynchus hectori). Endemic to coastal New Zealand waters, Hector’s dolphin is a rare but captivating marine mammal. It’s black head, stout body, and rounded dorsal fin make it easy to distinguish from other Pacific dolphin species. Within Cephalorhynchus hectori, two subspecies exist: Cephalorhynchus hectori hectori and Cephalorhynchus hectori maui. Though they remain genetically and morphologically similar, these subspecies have kept to their own respective turfs. C h. hectori are found primarily off the coast of New Zealand’s South Island and are represented by a little over 7,000 individuals as of 2010. C h. maui, on the other hand, is located on the northwest coast of the North Island. It’s also on the verge of extinction, with an estimated population of just 48-69 animals.
Hector’s dolphins, much like other dolphin species, exhibit relatively long life spans and low fecundity. Their primary diet consists of small fish, similar to those stirred up by trawling vessels. This combination of risky feeding behavior and k-selected life history traits makes for an unfortunate mix, as Hector’s dolphins have had a difficult time rebounding from population declines over the past few decades.
Fortunately, New Zealand has stepped in and implemented policies to protect these charismatic megafauna. The national government has banned gillnetting, a practice known to result in dolphin bycatch, in shallow waters within the Hector’s dolphin’s range. New Zealand has also placed restrictions on trawling and established five marine mammals sanctuaries throughout the species’ habitat. These sanctuaries should reduce the noise pollution and habitat disruption caused by other human activities, such as mining and acoustic surveying.
Enjoy the Podcast!