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There is an abundant amount of threats to the current Hector’s Dolphin population. Like any other species, humans have caused a significant decline in their population and the list includes, but is not limited to: illegal fishing, being caught up in gillnets, severed by boat propellers, contamination by toxic chemicals-resulting in decreasing fertility rates, human development near or on coastal waters resulting as a loss of habitat, and disturbance by boats.
Hector’s dolphin was named after James Hector who was believed to be the first person to have examined the species. Hector’s Dolphin is the smallest and rarest of the dolphins in the world measuring between four to five feet in length in full maturity, and weighing up to 110 pounds. To put it in perspective, other dolphin species like the Bottlenose Dolphin, ranges in size from 8-13 ft. their weight is also very dissimilar to that of Hector’s Dolphin, Bottlenose Dolphins weight ranges from 330-1,400 pounds. Hector’s Dolphin usually live up to at least 20-22 years of age, on the other hand, other species of dolphins such as the female bottlenose dolphins have been known to live for up to 60+ years, other species range from 28-45 years. Living up to 20-22 years old for Hectors Dolphins may not seem like much, but considering all the threats to them and their rapid declining population, 20-22 years old is an accomplishment.
Hector’s Dolphins are “endemic” to New Zealand meaning they are only found in the coastal waters of New Zealand, though their distribution is seen and scattered around the entire south island. Larger populations are found along the east and west coasts of the south island known as, Banks Peninsula (east) and Akaroa Harbour (west). Hector’s Dolphins are “divided” into four populations within the islands and consists of about 111 members, this is a problem since they tend to only mate within the population they belong to, decreasing chances of some sort of genetic flow.
Population size is currently about 7,300+ with a decreasing trend over the years. In the past it was speculated that the population reached about 50,000. Over time, the population has decreased dramatically due to the many threats that the human population has imposed on them as the human population continues to grow overtime.
Female dolphins can produce a maximum of seven calves during their entire lifetime, typically having calves every two to four years, making a potential population increase an immensely slow process. Gestation period lasts for 10-12 months, and once the offspring is born, they stay with their mother for about two years, during this time, the female is not sexually active. Fertility in this species is very fragile and affected heavily from disease and toxic chemicals, making an increase in numbers more difficult.
“Hector’s Dolphin.” WWF, World Wildlife Fund,
“Hector’s Dolphin.” NOAA,
“Hector’s Dolphin.” Marine Mammals,
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