Marine mammal health assessments are typically designed to specifically facilitate veterinary evaluations of animals.
However, situations can arise when we are able to provide medical intervention for a suffering animal. In this article, our Barataria Bay Capture Lead, Eric Zolman, describes how the members of our team responded to a dolphin (Tursiops truncatus) with fishing line wrapped around its head. Although we know that the research we typically conduct eventually helps inform conservation efforts, it’s especially rewarding to directly improve an animal’s quality of life in the course of our work. From Eric:
In September 2017, during a routine capture-release health assessment of common bottlenose dolphins in Barataria Bay, Louisiana, we resighted an individual dolphin with a hypopigmented and sunken scar around its head about 15 cm behind the animal’s eyes. We first identified this same dolphin in November 2010, which was when we first noticed the scarring, so something had been going on for a long time. We believed that some kind of fishing line caused the scar, but we were unsure if the animal was still entangled. After further evaluation and discussion, we decided to attempt capturing the dolphin so as to be sure (and seeing as we had a capture team in place!).
The potentially entangled dolphin was traveling in a tight group with three others.
The dolphins weren’t evasive, swimming near the bow of our boat, and even made our job easier by moving into shallower water with a pretty firm bottom. I made the decision that this was a relatively safe situation to try and catch the animals, and the catch boat set a net around the group of four. Soon after completing the set, one of the dolphins hit the net and became entangled. A chase boat with animal handlers was quickly on the scene, and her crew rapidly removed the entangled dolphin from the net, recognized it was not the scarred animal, and released it. This left a trio of dolphins swimming inside the net compass. We shrank the diameter of the net and were soon rewarded when all three dolphins piled into the net together. Our animal handling team again responded promptly, and all three dolphins were quickly and safely in hand.
The entangled dolphin proved to be a female, 226 cm in length. The veterinary team assessed the scarring via ultrasound and discovered by probing the wound an embedded and knotted monofilament fishing line still wrapped around the animal. We brought the dolphin, freeze brand YV7, aboard the processing vessel, where veterinarians carefully teased out the line from the scarred tissue, taking care to not leave any fragments behind while not inflicting any further damage. Just over an hour after setting the net, we released YV7 back into her home waters, free from the danger and discomfort of her nearly seven years of entanglement.
Since the disentanglement in 2017, field biologists saw YV7 in March 2018 during surveys in Barataria Bay.
From afar, YV7 looked healthy and was behaving normally. We’ll be sure to keep an eye out for her in future surveys and the 2018 CARMMHA Barataria Bay health assessment to monitor her progress!