Studying the World’s Rarest and Smallest Dolphin
This week, we are focusing our attention on another graduate student researcher abroad, Lindsay Wickman. Read on to hear about this marine biologist’s work to study and protect Hector’s dolphin in New Zealand!
Did you know that the land of the long white cloud is also home to the world’s smallest and rarest dolphin? The critically endangered Māui dolphin averages a mere 4.5 feet in length and is only found off the west coast of New Zealand's North Island. In 2010/2011, scientists estimated that the shrinking population was comprised of roughly 55 individuals over the age of one.
Hector’s dolphin mother and calf. Photo credit: Lindsay Wickman
Māui dolphins were recognized as subspecies of the more abundant Hector’s dolphin in 2002. Although the two subspecies are closely related, geographic and genetic isolation has resulted in small differences between each subspecies’ skeleton. The more abundant subspecies of Hector’s dolphin, which numbers between 12,000 and 18,500 individuals, is found in the coastal waters of New Zealand’s South Island.
In 2008, the New Zealand Department of Conservation created the West Coast North Island Marine Mammal Sanctuary to help protect these small, endangered cetaceans. The sanctuary restricts activities associated with acoustic seismic surveys and seabed mining. In addition, the New Zealand Ministry for Primary Industries has set fishing restrictions on set nets, drift nets and trawls over much of the sanctuary’s range. Given current fishing restrictions, scientists recently predicted that the Māui dolphin population has fallen to 43-47 individuals, approximately 10 of which are mature females.
So why are Māui dolphins continuing to decline? These petite, pale grey dolphins are typically seen swimming close to shore in shallow water in small groups or pods. According to the New Zealand Department of Conservation, this behavior means that Māui dolphins are affected by human coastal activity, and are at risk of ingesting marine trash and being hit by boat propellers. Most significantly, they are threatened by fisheries entanglement: dolphins caught fishing nets often drown. In addition to human threats, Māui dolphin are at risk of disease, predation and small population effects such as low genetic variability and variability in yearly survival and reproductive success.
Hector’s dolphins are found off the coast of New Zealand’s South Island, near beaches like the one pictured above on the Otago Peninsula. Photo credit: Melissa Lenker
The good news is that Māui dolphin research and conservation isn’t starting from scratch. Although Māui dolphins were recognized as a sub-species just 14 years ago, scientists have been researching Hector’s dolphin for decades. This means that scientists already have a great research database to jumpstart conservation efforts.
I had the opportunity to chat with Lindsay Wickman, a marine biologist and graduate student studying Hector’s dolphins at the University of Otago, about her research and what it means for the conservation of this well-studied species. Before starting her Master of Science, Lindsay interned with the Department of Conservation to enhance Māui dolphin media and communications. Read on to hear about Lindsay’s research and life as a marine biologist!
Melissa Lenker: How did you get into this field? Have you always been interested in marine biology?
Lindsay Wickman: I have been interested in marine biology since the age of eight. I grew up in land-locked Tennessee, but our school mascot was a dolphin. Our school slogan was “we can’t hide our dolphin pride!” As silly as it sounds, that’s what first sparked my interest in the ocean and marine mammals. When I graduated from high school, I went to the University of Miami and majored in marine science and biology. I found my current place at the Otago University Marine Science Department’s Marine Mammal Lab after a semester abroad.
ML: What kind of research are you working on right now?
LW: I am currently involved in the Otago University/NZ Whale and Dolphin Trust long-term study of Hector’s dolphins in Banks Peninsula. By photographing unique marks like the ones seen below, we can identify individuals and track them over time. This technique is called photo-ID, and we use this data to count how many dolphins use the area, determine social structure, and estimate parameters like survival rate.
Researchers like Lindsay use unique marks on Hector’s dolphins’ dorsal fins to identify individuals. Photo credit: Steve Dawson
The marks can help determine population parameters such as abundance, social structure and survival rate. Photo credit: Steve Dawson
Not all dolphins have these marks. The proportion of individuals that have these distinct markings is called the mark rate. Dolphins get these marks through interactions with others (e.g., play or aggression), predators (like shark bites), and from non-fatal encounters with fishing gear. In 1988, the Banks Peninsula Marine Mammal Sanctuary was established to protect dolphins from unsustainable set netting. The sanctuary has had positive impacts on the population. However, it’s a catch-22 – since fewer individuals are becoming entangled, fewer of them have marks, and this may make them harder to study. This brings us to my main research questions:
- What is the current mark rate of Hector’s dolphins at Banks Peninsula?
- If mark rate has declined, what are the implications for our ability to monitor how well the population is doing?
ML: How does your research influence dolphin conservation efforts?
LW: We may find that as mark rate declines, population changes may become harder to detect. For example, if survival rates are imprecise, it may take years longer to detect a population decline. In some of these populations, it may mean we need to refine photo-ID methodology or find alternatives for monitoring population change. Additionally, if we do find that mark rate has declined, it may lend further support to the success of the Banks Peninsula Marine Mammal Sanctuary in reducing dolphin encounters with fishing gear, which could bolster the credibility of using Marine Protected Areas to protect marine mammals.
ML: What kind of data do you collect?
LW: When we do surveys and find a group of dolphins, we stop and take photos of the dolphins’ dorsal fins. Usually, we purposely target dolphins with marked fins to ensure we have a good photo of each marked individual. However, for my research, I take pictures of each group of dolphins randomly, not paying attention to which dolphins are marked or not. By shooting randomly, I can determine mark rate as the ratio of photos showing marked dolphins to total photos taken.
Lindsay taking pictures of Hector’s dolphins in the field. Photo credit: Will Rayment
ML: What are the best and worst aspects of field research?
LW: The best! Hector’s dolphins are a joy to see in the wild, and every day in the field is different! I’m also thankful for beautiful scenery, amazing wildlife (penguins, seals, and others), getting to work with my talented fellow lab members, and learning new skills like boating.
The worst! Non-marine scientists may think I spend most of the day with the dolphins, but actually we spend most of the day looking for them! Some days, we may find very few dolphins, if any at all. Field days can be tiring and long. After an early wakeup, we may be on the water for up to ten hours. Once off the water, there are often hundreds of photos to sort through before dinner and bed. It’s an intense time, but extremely rewarding.
Hector’s dolphin. Photo credit: Steve Dawson
ML: What can citizens in New Zealand and abroad do to help conserve Māui dolphins?
LW: New Zealand citizens should write to the Minister of Primary Industries about their concern for the species and their support for a ban on set netting out to 20 nautical miles throughout the Māui dolphin’s range. If you live abroad, your voice will still be heard!
Choose seafood caught using dolphin-friendly methods, like line- and trap-caught fish. Avoid fish caught using set nets or trawls. Also, tell your friends! You can also subscribe to the Department of Conservation’s Māui watch newsletter and learn more about the campaign to end set netting in Hector’s/Māui habitat.
University of Otago campus where Lindsay is a graduate student in the Marine Science Department’s Marine Mammal Lab. Photo credit: Melissa Lenker.
ML: Do you have any advice to aspiring marine biologists considering graduate school?
LW: When picking a lab, talk to current students about their experience with their advisors and the lab culture in general. Keep in mind that you’ll have a close relationship with your fellow students and advisors, so personalities should match! Have a look at past graduates, and the kinds of jobs they’ve gained. Choose a lab group that matches both your research interest and your ethics. Lastly, make sure you choose a project you’re passionate about. While advisors can provide tremendous support, graduate school is primarily self-motivated, so you need to bring your own enthusiasm.