By Dr. Russ Andrews
For the second year, researchers from Alaska traveled to the southeastern U.S. to work with the Georgia Department of Natural Resources, Florida Fish and Wildlife Conservation Commission, Sea to Shore Alliance and NOAA Fisheries to deploy LIMPET satellite tags on North Atlantic right whales. The agencies’ goal is to develop a minimally invasive satellite tag optimized for use on right whales that will provide sufficient tag attachment duration to track movements of whales migrating north from the southeastern U.S. and into the Mid-Atlantic region.
Having only been able to tag three whales in the last season — due to bad weather and fewer whale sightings than normal — this year the team started earlier, on Dec. 20, 2015, and stayed longer. Their preferred tagging candidates were juvenile whales (younger than 6 years old) and males, but this season there wasn’t a single sighting of a juvenile or a known male in the Southeast. Therefore, after two weeks spent searching for good tagging candidates, the tagging team trailered their boat to Charleston, S.C., to follow along with the Sea to Shore Alliance aerial survey team in the hopes that some whales were hanging out a bit farther north due to the unusually warm sea-surface temperatures along the coast of north Florida and Georgia at that time.
The team got lucky that day and the plane found a single whale, Eg4040, nicknamed Chiminea, a whale of unknown sex and age that had first been seen in 2010. The team deployed a LIMPET tag on Chiminea, which had been spotted less than three days before about 6.5 nautical miles off Jacksonville Beach, 150 nautical miles to the south-southeast. After being tagged, Chiminea continued heading northeast, following a very similar migratory path to the two whales that were tracked north last season (see map). Unfortunately, Chiminea’s tag stopped transmitting three days later.
A second whale, Eg4094, a 6-year-old female, was tagged later in January. Being nearly three years younger than the mean age of first reproduction, the likelihood that she was pregnant was very low. However, five days after tagging, Eg4094 seemed to change her movement pace, so the Sea to Shore aerial team headed out to check on her, even though the satellite tag data showed she was farther offshore than the end of their survey line. It was fortunate they did fly past the end of their line to search for the whale because they spotted her with a newborn calf.
Eg4094 had been observed on the previous afternoon without a calf, so the calf was less than 20 hours old. Unfortunately, as calves often do, this one was seen bumping against its mother and swimming right over her head and back, and the tag stopped transmitting less than a day later, likely because the calf dislodged it. Eg4094 and her calf have been spotted more than 10 times since, and the tag implant site looks very good, with just two small holes that appear to be healing as expected.
Two other whales that had been travelling together for many weeks were also tagged, but their tags stopped transmitting within a day, likely due to getting bumped off during the close interactions that were observed between these two whales.
The team has now tagged seven North Atlantic right whales with LIMPET tags, and although one whale’s tag transmitted for 50 days and another for 15 days, the rest of the tags unfortunately did not last more than one week. Despite having provided some very valuable data on the movements of North Atlantic right whales through the Mid-Atlantic, the team will now focus on developing a slightly modified tag that will hopefully improve the duration of attachment, without increasing the impact on the tagged whales.
Dr. Russ Andrews of Alaska SeaLife Center/University of Alaska Fairbanks, is the principal investigator on the right whale satellite tagging project.