CEPHALORHYNCHUS HECTORI

These is a little bit of information of Hector's Dolphin, in respect to Sir James Hector the founder of this species. Sir James Hector is a New Zealand zoologist. This dolphin's scientific name is cephalorhynchus hectori.

HABITAT

The Hector’s dolphin major habitat type is the coastal waters and is found at the North and South Island at the New Zealand Marine. They live close together in small groups close to the shore and hardly swam further than 30 kilometers from the shore. The dolphins live in a range of water temperature with surface temperature of 6.3 °C to 22 °C and water turbidity of around <10>15 meters.

The North and South Island dolphins are separate species and are genetically and physically different from each other. The subspecies of Hector’s dolphin is known as the Maui’s dolphin. The dolphins are normally found in isolated groups along the north-west coast of the North Island between Dargaville and Taranaki while the Hector’s dolphins are found at the South Island. The total population of the dolphins is somewhere between around 5,000 to 7,000 dolphins and is still decreasing.

FEATURES-APPEARANCES

The dolphins colour is a pale grey but with a closer look it actually has a complex tapestry kind of colour on it. Its forehead is grey which has streaks of black on it. The tip of the dolphin’s beak is black while the throat and chest are white. There is a dark grey patch that runs from the flippers which are also dark grey till the eyes. The belly is white with a stripe that runs from up the sides of the dolphin under its dorsal fin. The bulk at the back and sides are the same colour as the beak. It has about 52-64 teeth both on the top and bottom rows.

The dolphins weigh about around 9 kilograms at birth and grow to about 40-60 kilograms when they are at their adulthood. They dolphins live to about 20 years and are usually in groups of about 2-8. They are active dolphins and do bow-riding and often play with seaweed. When the dolphins leap from the sea, they usually land on their side, creating a loud splash whereas their vertical and horizontal dives are less noisy. The dolphins also surface frequently to breathe which shows a little of their bodies.

FEATURES-DIET

The Hector’s dolphin feed mostly on pelagic and benthic species that are living below the violent weather zone and in shallow waters with a sandy bottom. For example creatures like red cod, mackerel, crabs, flounder or squid. They also occasionally eat krill or other crustaceans in the ocean. Feeding is a group activity for the dolphins. They feed both at either the top or bottom of the ocean and eat about 4 kilograms of fish everyday. The Hector’s dolphin on the East Coast have been found that they mainly eat arrow squid, red cod, Ahuru, sole, stargazer, yellow-eyed mullet and sprat. In summer, the dolphins sometimes follow the inshore trawlers, putting themselves behind the end of the net to find food.

WHY IS IT ENDANGERED?

• Set nets, commonly used to fish in New Zealand.

• A low birth-rate so their population doesn’t increase quickly.

• Trawling a fishing method and also a threat to the dolphins.

• Reckless boat users who do not watch out for the dolphins.

• Marine pollution such as plastic bags, rubbish - these animals ingest them but do not digest them and die of suffocation

• Polluted waters can make the dolphins sick by decreasing the amount of oxygen available.

• Are threatened by human activities such as fishing, habitat destruction and hunting competitions.

• Gillnets usually gets entangled with the dolphin and causing them to drown.

• Due to incidental catches such as the catch of large numbers of dolphins in coastal gillnets and normal fishermen nets where they die of suffocation

• Pollutants such as heavy metals or pesticides on the coastal distribution of the species make it vulnerable, which lowers their immune system leading to more diseases being caught by them and they are then left to die in agony

These magnificent creatures have been facing extinction for quite sometime.The dolphins was given the call “threatened species” status by the Department of Conservation during the month December on the year 1999. They have not stopped facing the threat since then. A number of actions have been taken to secure the numbers of Hector's dolphin but none of them were very successful. Their numbers have been gradually decreasing due to the usage of various fishing nets in New Zealand. A law should be brought up against these fishing nets, limiting it only to either the set nets, trawler nets or gillnets. As this are the major causes of their decrease in numbers.

Some of this information have been gathered by *Maddy for her presentation. Thank you!