Summer brings longer days, warm ocean swims, and perfect weather for outdoor activities. It also brings lots of dolphins to Roanoke Sound!
Since 2008, the Outer Banks Center for Dolphin Research (OBXCDR) has monitored the local dolphin population in the sound through photo-identification. Bottlenose dolphins are distinctive by natural markings on the dorsal fins. The OBXCDR uses a small boat to travel throughout the sound and photograph the dorsal fin of each dolphin sighted. Geographic location, group size estimates, and activity state of each is recorded as well. This information is used to track individual dolphins over time and study the population size, ecology, and health of dolphins in the Outer Banks.
Every spring, OBXCDR researchers plan out the field season. Volunteers complete annual boat trainings to refresh on survey protocols. Since April, the OBXCDR has completed approximately four surveys per month, and many of our seasonal residents have returned to Roanoke Sound.
Many people ask, “do the dolphins have personalities?”
Here is a summary of our “cast of characters” for Roanoke Sound this summer, who has returned:
- Onion is one of the most distinctive dolphins in our photo-identification catalog and, thus, the best known throughout the Outer Banks. An older male dolphin, Onion has been sighted in the area since 1997. He is frequently seen by OBXCDR researchers in the sound as well as by beachgoers basking near Oregon Inlet. Much of what we have learned about the movement patterns of dolphins in northern North Carolina has come from tracking Onion. Through Onion we have learned that many of our Roanoke Sound dolphins also frequent the waters as far south as Beaufort, North Carolina. Onion and many of our “seasonal residents” are commonly sighted in Beaufort, NC during the winters.
- Fatlip is a female bottlenose dolphin frequently sighted in Roanoke Sound. She is distinctive by the markings on her fin that resemble one of a pair of fat lips. Over the years, we have seen Fatlip with at least 5 different calves! Female dolphins invest a lot of time and effort in raising their calves; some calves may stay with their moms for as long as six years. Fatlip’s first sighting of the year in Roanoke Sound was on May 13, 2019. She was seen near Oregon Inlet with her 3-year-old calf and has since been sighted with a newborn calf near Wanchese.
- Sequoia and FB708 are male bottlenose dolphins commonly seen in Roanoke Sound. Sequoia received his name for the white scarring on his dorsal fin that resembles that bark of a sequoia tree. FB708’s name stems from his freezebrand that he received during a tagging study nearly 20 years ago. For many years, these males held a stable bond as is common for adult male dolphins. The two were frequently sighted together in the sound, foraging or herding females. Through the years of watching Sequoia and FB708, we have learned more about this common strategy that males adopt for survival and reproductive benefits and how these pairs can change over time. Sequoia and FB708 have both been sighted this year, yet never together! Since last summer, Sequoia has formed a new pair with another male, Jetson, and FB708 has been by himself. We still do not fully understand why the pair has split, but hope to learn more as the summer season goes on.
Through our long-term monitoring study, we are able to track these dolphins year after year, learn more about their lives, and how to better protect them as well as our marine environment. Dolphins are important indicators of environmental health. By studying the dolphins, we can identify early warning signs of problems in our marine environment whose health our local economy depends upon.
There are still many questions to answer about the dolphins, such as: Where else do they go when they are not in Roanoke Sound? Why do male pairs split up? How often do females have their calves? Our next research survey alone will not provide the answers to these questions, but over time, we hope to learn more about these questions and many more.
The next time you see a dolphin at the beach or from a boat in the sound, look closely at the dorsal fin. It may be one of “Onion’s group” — an Outer Banks regular who enjoys the local beaches and sounds as much as we do.