Marine Mammal Photo-Identification Research in the Southeast
We use photos to identify, catalog, and study marine mammals in the Southeast. These photos provide important information about the health, social structure, abundance, and distribution of marine mammal populations.
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Just like fingerprints are unique to each person, whales and dolphins (cetaceans) also have physical features unique to each individual. NOAA Fisheries scientists use these features in photo-identification (photo-ID) studies to track individuals over time. This allows us to better understand various biological parameters—such as life span, calving rates, social structure, and behavior—and to assess the species’ abundance, distribution, and movement patterns. In the waters of the Southeast United States, we use photo-ID to study several species including Rice’s whales, sperm whales, killer whales, and common bottlenose dolphins.
The distinctive features used to identify individuals vary by species. Some distinctive markings are present when an animal is born, such as the eye patch of a killer whale. Other markings, such as dorsal fin and fluke notches and body scars, are acquired throughout the animal’s life. These markings may result from:
- Playful or aggressive contact with other whales and dolphins
- Interactions with predators such as sharks or killer whales
- Encounters with fishing gear, watercraft, and marine debris
Certain diseases and environmental conditions, such as extremely low salinity, can cause lesions and other irregularities to the skin, which can also aid in identification.
Why Conduct Photo-ID Research?
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Conservation and management requires a basic understanding of the biology and ecology of each marine mammal population together with the threats they face. We use photo-ID research to:
- Estimate the population size and identify trends over time
- Compile information about range and distribution
- Examine habitat use and site fidelity of individuals
- Study behavior and diet
- Assess lifespan, social structure, and reproduction
- Document body condition, disease, and evidence of predation
- Examine impacts of natural events such as storms and algal blooms
- Identify and assess human threats
How Do We Conduct Photo-ID Research?
Collecting Photos
All marine mammals are protected under the Marine Mammal Protection Act. Before conducting marine mammal photo-ID surveys, we obtain a scientific research permit that allows us to approach the animals safely and carefully to limit disturbance. We also acquire Institutional Animal Care and Use Committee approval to comply with the Animal Welfare Act.
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Our photo-ID surveys are designed around a specific species in a designated area where they are known or expected to be found. Data collection starts with trained crew members working from a small boat searching for animals, typically along a predetermined survey route. Each time there is a sighting, researchers attempt to photograph all individuals in the group. In addition, we record data with each observation including:
- Estimated number of animals in the group
- Estimated number of adults and calves
- Behavior exhibited by the animals (like socializing, feeding, traveling)
- Environmental conditions (including cloud cover, wind, water temperature, sea state)
- Record any visible markings (such as wounds or scars from sharks, fisheries entanglement, vessel strikes)
- GPS coordinates of sighting location
Analyzing Photos
After conducting a photo-ID field survey, researchers return to the office to review the photographs. They sort images by individual and record the number of unique individuals in the sighting. Then, we select the best picture of each individual and compare it to the catalog of previously identified animals. Many NOAA researchers use the FinBase database system to catalog their images of known individuals and to assist in the matching process.
We also use artificial intelligence programs to aid in matching these photos to known individuals in the database. Computer algorithms can be trained to trace selected features and provide a list of the best potential matches, which the researcher then reviews. To minimize matching errors, a second expert confirms all potential matches before the images are added to the catalog. If we don’t find a match, we give the animal a new unique identifier and add it to the catalog.
Each catalog contains individuals identified through photo-ID surveys in a specific geographic area. For example, there are bottlenose dolphin catalogs for several different areas of the Southeast such as Terrebonne-Timbalier Bays, Louisiana, Mississippi Sound, Mississippi, and Biscayne Bay, Florida. We are also developing catalogs for other species in the Southeast including Rice’s whales, sperm whales, and killer whales.
Photo-ID Simulation: Can you make the match?
Dorsal Fin Matching
Below you will see several images of common bottlenose dolphin (Tursiops truncatus) dorsal fins. The photos on the left were taken during photo-ID surveys recently conducted in Biscayne Bay, Florida. The images on the right are from our existing Biscayne Bay photo-ID catalog. Can you match the newer photos on the left to any of the individuals from the catalog on the right?
Can you match any of the fins on the left (A-C) to the catalog on the right (numbers 1-9)?
The correct matches are below. If you wish to challenge yourself, don’t scroll down until you have finished matching fins!
Fin A
Did you correctly identify fin “A”? This fin (A) is a match to photo number 5 on the right. In the Biscayne Bay catalog, this dolphin’s unique identifier is 008.
Fin B
How about these matches? Animal B is tricky! This dolphin had a few fin changes. Did you notice it matched both photo 1 and photo 9 from the catalog? Photo 1 was taken in 2013 when the dolphin was a calf, still traveling with its mother, who is Biscayne Bay catalog number 008 above. The second picture matching animal B is photo 9 from the catalog on the right. In photo 9, you can see a new large notch in the upper portion of the fin. The most recent image of Fin B on the left, was collected in 2018 after another change in which it lost the top half of the fin. This animal is Biscayne Bay dolphin number 350.
Fin C
If you didn’t find a catalog match for animal C, you are correct! Sometimes we come across an animal that is not in the catalog. Once it is confirmed there are no matches, we give the dolphin an ID number and add it to the catalog.
Marine Mammal Publications using Photo-Identification as a Tool
- Photo-identification capture-mark-recapture techniques for estimating abundance
- Photo-Identification and laboratory protocols utilizing FinBase version 2
- Using Photo-Identification and Genetic Data to Examine Fine-Scale Population Structure of Common Bottlenose Dolphins in the Estuarine Waters Surrounding Savannah, Georgia
- Long-Range Longitudinal Movements of Sperm Whales in the North Atlantic Ocean Revealed by Photo-Identification