By Ellen Bausback, Education & Communications Intern / UF Thompson Earth Systems Institute
Published May 20, 2020
Randall Wells doesn’t have a favorite dolphin. After working for 50 years with the Chicago Zoological Society’s Sarasota Dolphin Research Program, Wells just calls the curious cetaceans “our neighbors.”
Wells, the program’s current director, helped found the organization in 1970 and has been researching dolphin social behavior and habitat in Sarasota Bay and other Florida waterways ever since. The program was one of the first to use long-term tracking to systematically map out the lives of dolphins and study where they go.
From using simple numbered tags without electronic components to pinpointing individuals using distinctive markings like scars and notches in fins, scientists studying marine species can identify animals after multiple encounters. And in recent years, radio, GPS and satellite technology have made it possible to monitor a variety of marine species even more closely via small tracking devices attached to animals’ bodies.
A screenshot of a radio tracking map on the Sarasota Dolphin Research Program website.
As the climate changes and human influences on our waterways escalate, scientists like Wells say keeping track of where animals go and how well they survive is essential to wildlife management decision-making.
The Evolution of Tracking Technology
Wells didn’t start out following the movement of dolphins with advanced tracking technologies like GPS and satellite—he started by using “big, clumsy” tags that used CB radio signals tuned to the same frequencies as cross-country truckers.
“The truckers in Omaha were probably listening to the beats from our dolphins and wondering what government body was listening in,” Wells said. “There weren’t a lot of frequencies to work with back then.”
Today, tracking technology has become more refined and efficient.
Wells and his team now use smaller radio tracking devices that are about the size of an adult’s pinky finger. Other modern GPS and satellite telemetry trackers are only the size of two fingers and can be powered by a single double A battery. New types of trackers can work for months and transmit complex information about location, dive depth and duration to anywhere.
New tracking technology uses satellites, which can transmit complex information about wildlife to anywhere. (Photo from Unsplash
“That's really opened up our ability to learn about these animals in the wild in amazing ways,” Wells said.
In the past, dolphin trackers often covered the entire dorsal fin and were restrictive because they created drag for the animal, impeding its movement, he said. Today, scientists place newer, lighter trackers on the dolphin's fin using a single pin, just like an earring.
A satellite-linked, time-depth-recording tag on an adult female bottlenose dolphin in Sarasota Bay, Florida. (Photo taken by the Chicago Zoological Society's Sarasota Dolphin Research Program under National Marine Fisheries Service Scientific Research Permit No. 15543. Courtesy Dr. Randall Wells).
The dolphin’s movement track is displayed in real-time through a receiver on a researcher’s boat. Scientists onboard can view information about a dolphin's dive depth, pattern and duration.
“It is fun. It’s like you’re opening up presents,” Wells said. “You never know what you’re going to get until you open it up and see what these animals are doing.”
Dolphins aren’t the only flippered fauna to be studied using tracking technology.
Angela Collins, a Florida Sea Grant Agent with UF/IFAS Extension, has used acoustic tagging to study fish. This involves placing small trackers on their fins that emit signals at specific time intervals. The tags provide information about the ID of the fish, swimming depth and speed, and even stomach pH. Whenever the fish comes within range of a receiver that is deployed on the ocean floor, the receiver records data that scientists can then access, Collins said.
Hogfish are one of many species of fish that are monitored using tracking. (Photo from iNaturalist
user Mark Rosenstein, CC-BY-NC-SA 4.0.)
Collins noted that tagging in general has expanded from being a niche field to being collaborative and widespread.
“It's just started to explode because things have become so much cheaper,” Collins said. “Having all of these researchers create this awesome communication network is a really nice way to share data and get more out of your equipment than you ever thought possible.”
How Tracking Discoveries Inform Policy
The Florida State Capitol building in Tallahassee, where many legislative decisions are made. (Photo from Wikimedia Commons
user Michael Rivera, CC-BY-SA 3.0.)
Animal tracking technologies like the ones Collins and Wells used have led to important discoveries that help scientists learn more about problems facing Florida wildlife and possible management solutions.
Using these tracking and tagging techniques, Wells and his team discovered that the same population of dolphins has stayed in Sarasota Bay generation after generation. So far, they’ve studied six concurrent lineages.
Being able to determine that a certain population of dolphin stays in the same area for an extended period is important for wildlife management agencies because it can help them measure impacts, such as declining water quality, on the species over time, Wells said.
This is especially important because in many ways, dolphins can be an indicator species—problems with their populations can signal larger problems for the marine environment.
Collins has used tracking technology with fish during an annual initiative called the Great Goliath Grouper Count.
Atlantic goliath grouper like this are counted each year during an annual initiative called the Great Goliath Grouper Count. (Photo from iNaturalist user bronyaur, CC-BY-NC 4.0).
During the count, scientists and anglers work together to record the amount of goliath grouper observed and assess the fish’s population. This long-term data set will help scientists determine if the species has recovered since harvest and possession restrictions were set in place in 1990, and whether management agencies should revisit those restrictions.
Tagging has also been essential through Collins’ research with gag grouper and hogfish, which can suffer from barotrauma if they are reeled to the surface too quickly.
Barotrauma occurs when fish are unable to adjust to the pressure difference between their deep-water home and the surface. Symptoms of barotrauma include a bloated stomach pushed out through the mouth, protruding eyes and a ruptured swim bladder, according to Florida Sea Grant.
Atlantic goliath grouper can experience barotrauma if they are brought to the surface too quickly. (Photo from iNaturalist user bean-b (CC-BY-NC 4.0).
Knowing catch-and-release survival rates is essential for fish like gag grouper, which play an important role in the reef food chain. Wildlife managers want to maintain healthy populations while also understanding that grouper are economically important for commercial fishermen and a sought-after recreational catch.
“Estimating survival after catch-and-release for the species that are susceptible to barotrauma is really important to management so you can get an idea of just how many of these fish that are being released are actually surviving,” Collins said.
Collins said a Florida Fish and Wildlife Conservation Commission research team in the Florida Keys tags fish underwater to prevent barotrauma. Scientists in scuba gear flip the fish upside down, make an incision, insert a tracker in its body cavity and stitch it back up, all under the sea.
Tagging can also help scientists determine survival of animals once they are released following medical rehabilitation.
“It’s a really, really expensive and time-consuming process to rehabilitate a dolphin,” Wells said. “And you want to make sure that what you’ve done has actually made a difference in the life of that animal.”
Tracking technology also helps scientists better understand the behavior of offshore aquatic animals that would be hard to study otherwise. For example, dolphins that live in the open ocean as opposed to enclosed bays may be hard for scientists to regularly access.
The Sarasota dolphin team had a project planned, that has since been postponed due to COVID-19, to track dolphins off the West Florida shelf that might have been affected by the Deepwater Horizon oil spill.
“We want to gather baseline information on these animals while there is no catastrophe going on, so we'll have something to compare when the next disaster happens,” Wells said.
Back to Basics
An Atlantic horseshoe crab in the sand. (Photo from iNaturalist
user Oscar Johnson, CC BY-NC-ND 4.0.)
Savanna Barry tracks living fossils and says citizens can get in on the animal tagging action, too.
The regional specialized extension agent for Florida Sea Grant tags horseshoe crabs, a species that has remained relatively unchanged for its nearly 445 million years of existence.
Scientists need to keep track of horseshoe crabs for several reasons, for one because their blood is a hot commodity in the biomedical industry. It contains a compound called Limulus Amebocyte Lysate, or LAL. The U.S. Food and Drug Administration uses LAL to make sure all injectable drugs in the country are sterilized, because LAL clumps up in the presence of certain bacteria.
In addition, horseshoe crabs are an important part of the marine food chain. Animals like shorebirds feed on horseshoe crab eggs, and adult crabs are a food source for sea turtles, sharks and more, according to the Florida Fish and Wildlife Conservation Commission.
Aquariums also collect these animals for use in displays and for education programs and research, and crabs are used as bait in eel and conch fisheries.
Unlike the fancy radio and acoustic tags Wells and Collins use, Barry says tagging these ancient creatures is pretty low-tech and inexpensive. Step one: punch small holes in their shells. Step two: insert a simple plastic tag stamped with a unique number.
When a tagged crab makes its way to shore to mate, citizens can report the sighting to the Florida Horseshoe Crab Watch program. The program began as a small initiative in Cedar Key but has since expanded statewide.
Sea Grant agent Savanna Barry conducting a horseshoe crab survey in Cedar Key, Florida. (Photo taken on 03-30-17, courtesy of UF/IFAS Photo and Tyler Jones.)
Barry said scientists aren’t the only ones who can help collect data. Twice a year, anyone can volunteer with the program to help tag horseshoe crabs.
“They don’t cooperate and stand on a scale like we do at the doctors,” Barry said, so weighing them involves placing the squirming crabs and their flailing five pairs of legs in hanging reusable grocery bags.
Because horseshoe crabs can take up to a decade to reach maturity, they are at a higher risk for overexploitation. Barry says having sound population data helps fisheries managers ensure the population is properly sustained.
The same goes for many other marine animals in Florida. As the climate changes, technology like tracking can be an essential tool for conservation and can help inform future management and protection decisions.
"From a human perspective, these dolphin serve as sentinels of ecosystem health," Wells said. "They breathe the same air that we breathe. They catch the same fish that we catch and eat. Things are going to impact them before they impact us. We need to give them a chance to do the things that they need to do to continue to survive and thrive."
Learn more: Anyone can access online tracking databases and see where animals go for themselves by accessing FWC’s iTAG to check out current projects or getting familiar with turtles and great white sharks on Ocearch’s extensive tagging network.