Scientists have developed a groundbreaking new ultrasound technique to study dolphin pregnancies throughout all stages of gestation, just like we do for humans, in what they are calling a “game-changer” for dolphin conservation.
Ultrasounds for dolphins are not new; the list of animals that have been monitored using ultrasound during pregnancies is long – cats, dogs, horses, even hippos – but some animals are easier to monitor than others.
Now, researchers at the National Marine Mammal Foundation (NMMF) have revealed they’ve found a way to evaluate dolphin fetuses at all stages of a pregnancy, which could have a huge impact on dolphin reproductive success, publishing their findings in Veterinary Radiology and Ultrasound.
The 2010 Deepwater Horizon oil spill is the largest oil spill – and considered one of the worst environmental disasters – in history. It released around 4.9 million barrels (210 million gallons) of oil into the Gulf of Mexico, massively reducing reproductive rates in bottlenose dolphins in the area.
A 2017 study estimated it would take nearly 40 years for dolphin populations affected by the spill to recover. Another study found that dolphins living in the area gave birth to live calves only 19 percent of the time, compared to the 65 percent experienced by unaffected populations.
Since then huge efforts have been made to understand why the pregnancies failed, and how conservationists can help ensure more are carried through to full term. This new ultrasound technique means researchers can monitor dolphin fetuses through each trimester, which should flag up any abnormalities, and improve success rates.
"We can now re-create the human 20-week fetal ultrasound exam in dolphins, which means we can better understand the health challenges dolphin mothers and their babies are facing," said NMMF Executive Director Dr Cynthia Smith in a statement. "This is a game-changer for the conservation of bottlenose dolphins and other small cetaceans around the world."
The non-invasive ultrasound images allow researchers to determine any issues in the pregnancy much earlier on, and even accurately determine the due date, which allows for a timescale for any decision making regarding surgery or care.
"This advanced ultrasound technique is allowing us to diagnose problems as early as the first trimester of pregnancy in dolphins," said Dr Forrest Gomez of the NMMF. "That gives us a chance to determine if there is something that could be done to save the pregnancy, which could prove critical for populations of dolphins and porpoises that are at risk."
To develop the technique, 16 healthy pregnancies were monitored between 2010 and 2017 in a group of human-managed dolphins. Over 200 ultrasound scans were taken, and 70 factors meticulously recorded in each scan of the fetus and placenta to build up an accurate idea of a normally progressing pregnancy that can be used for comparison by conservationists around the world.
"This new technique can be performed in a matter of minutes and provides a wealth of information about the health of the dolphin fetus," added dolphin radiologist Dr Marina Ivančić. "We are thrilled to make this technique widely available to veterinarians and radiologists, which has the potential to elevate dolphin medicine globally."
*(C) Yes, that's a dolphin penis in utero, while (D) shows a dolphin vagina.