It was a hot day out in Barataria Bay, but with no wind and slick conditions, we could easily see dolphins as they rose above the water’s glassy surface.

Today we patrolled the waters around Fifi Island and Grand Terre. We left yesterday’s blog with the animals safely in our expert dolphin handlers’ hands with a team of veterinarians monitoring the dolphins’ behavior and well-being. If the veterinarians are worried about how a dolphin is reacting to the handling process, they will work with the handlers to improve the situation quickly or, as a last resort, release the dolphin early.

On this day, we worked with four animals: a first-trimester pregnant female, a single adult male, and a pair of adult males. Three of the animals had never been assessed before.

For the most part, the majority of the animals we work with prove to be calm and cooperative after the initial surprise of capture. In these situations, the veterinarians will take blood samples from the flukes as soon as possible. These samples get sent to our floating laboratory aboard the Lady Camille, where the sample processing team gets to work. Once the blood collection is complete, the veterinary team determines the order of health assessment activities based on the animal’s age, sex, physical appearance, and behavior.

CARMMHA team conducting dolphin health assessment.
The CARMMHA team conducting an ultrasound scan during a routine dolphin health assessment.

Typically, the next step is to perform our new cardiac assessment techniques, including auscultation and echocardiography. Drs. Sharon Huston and Adonia Hsu carefully listen to each animal’s heart using a stethoscope (auscultation), concentrating particularly on any potential heart murmurs or other audible abnormalities. Then, Dr. Forrest Gomez uses a field-ready ultrasound machine to look at the dolphin’s heart using echocardiography. She takes pictures and videos of the heart so that we can measure the size of heart and how well it moves blood from one chamber to the next.

The ultrasound machine is very similar to the ultrasound machine doctors use to look at a fetus in a pregnant woman, and not surprisingly, we also use the ultrasound machine to determine whether adult females are pregnant.

Today, we caught an adult female and saw (using ultrasound) that she is carrying a first-trimester fetus. One difference between a dolphin pregnancy compared to a human one, is that dolphins typically carry their offspring for 12 months, rather than the 9 months that humans do. In some pregnant animals, our veterinarians can even identify the sex of the fetus! Finally, in addition to a cardiac scan and a reproductive scan, the team will use ultrasound to look at other organs to check for signs of disease. For example, Dr. Cynthia Smith has documented significant lung disease in dolphins living in Barataria Bay.

Ultrasound image of a live dophin fetus acquired by NMMF’s Cynthia Smith and Veronica Cendejas in Barataria Bay 2011 (NMFS permit #932-1905/MA-009526). (Provided by Cynthia Smith)

In addition to the blood samples and the cardiac assessment techniques, and depending on the overall appearance of the animal, the veterinarians may collect blubber, skin, mucus, and urine samples, as well as other health-related data.

  • Size: weight, length, girth, etc. tell us about the animal’s body condition,
  • Breath CO2 levels: tell us about the animal’s respiratory health,
  • Age: using dental x-rays(!), and
  • Lesions: they typically have lots of scratches and superficial wounds. One of the dolphins today had a football-sized abscess!

Throughout this entire process, the veterinarians are always monitoring the animal and will decide to release an animal if anything looks like a problem. Together, the samples and data they collect are at the heart of our CARMMHA team’s ability to answer our research questions. These data will inform our Integrative Modeling team’s expert elicitation and modeling efforts to quantify how health effects result in stock/population-level changes.

 

* * *

ASK A DOLPHIN EXPERT!

How do dolphins eat with their tiny little teeth?

Dolphins usually swallow fish whole. They typically only use their teeth to tear the prey into smaller pieces if the fish is too large to swallow in one bite or to hold onto the prey so it doesn’t wriggle away prior to swallowing it.

About this field update

The CARMMHA Barataria Bay Health Assessment wrapped up last month! The team spent two weeks on Grand Isle, LA and had a very successful fieldwork effort. During the trip, CARMMHA Research Coordinator Ryan Takeshita (with plenty of help from others on the team!) kept a field journal to share here on the CARMMHA website. Over the next two weeks, we’ll post daily blog entries from that field journal. In some of the entries, we have a Question and Answer section with marine mammal veterinarians responding to questions from Evie, a four and half-year-old scientist in training from Ellicott City, MD. We hope you enjoy our field updates!