Dolphin Y01 pushes a dead calf in March, 2013. The team even observed one dolphin pushing her dead baby in the bay waters, a behavior that’s been observed in other female dolphins towards their dead calves, the authors write. So that’s an approximately 60% lower pregnancy success for dolphins in Barataria Bay as compared to a reference site.” “In comparison, a previously reported study in Sarasota Bay, Florida reported a pregnancy success rate of around 83%. “Only 20% of the pregnant dolphins that were sampled in 2011 produced viable calves,” Schwacke said. This rate of reproduction is unexpectedly low, the authors write.

The team found that only two of the ten pregnant dolphins had successfully given birth to babies. To find out how many pregnant dolphins successfully gave birth to viable calves, Schwacke and her team monitored the dolphins’ movements for the next four years. Since a newborn dolphin swims in close proximity to its mother, an associated calf is straightforward to identify, Schwacke said. Cynthia Smith, National Marine Mammal Foundation. Dolphin Y37 was seen with a live calf in both April and August of 2012. Boat-based surveys documented that the pregnancy was successful. Dotted line shows the skull biparietal diameter, which is used to estimate gestational age and parturition date. Reproductive ultrasound image of dolphin Y37 showing an approximately 18-week gestational age fetus in a longitudinal plane, acquired in August of 2011. The researchers measured the dolphin fetus skulls to estimate the dates they might be born, and released the dolphins back into Barataria Bay. Using ultrasound, the team also found that 10 dolphins were pregnant. In 2011, as part of the Deepwater Horizon Natural Resource Damage Assessment (NRDA), researchers from NOAA and other institutes assessed health of 32 bottlenose dolphins in Barataria Bay, Louisiana, in the Gulf of Mexico, and found that most dolphins showed high prevalence of lung diseases and other health disorders. “The population has not only lost adult (reproductive) females that died following the spill, but this study now shows that the remaining females are not able to birth calves at a normal rate,” co-author Lori Schwacke, a wildlife epidemiologist, told Mongabay in an email statement. The study was led by the U.S.’s National Oceanic and Atmospheric Administration (NOAA). Of the dolphins that have managed to survive in the oil-contaminated waters, many are failing to reproduce, according to a new study published today in the Proceedings of the Royal Society B. Hundreds of dead bottlenose dolphins continue to wash ashore, five years after the catastrophic Deepwater Horizon oil spill in the Gulf of Mexico in 2010. Researchers even observed one female dolphin pushing her dead baby in the water.Researchers monitored the dolphins for next four years and found that only two produced viable calves.

During a health assessment of bottlenose dolphins in 2011 following BP oil spill, researchers found that 10 of 32 sampled dolphins were pregnant.Remains will be delivered to local iwi once all testing has been completed. Two DOC rangers who responded to the report, assessed the site, took measurements and photos of the dolphin before removing it from the area. Either way, the mother was unable to give birth due to the abnormal position of the fetus, resulting in the mother dying of blood poisoning.”Ī man discovered the dolphin on the beach on Sunday 30 September, around 20 km north of Raglan and reported the sighting to DOC. Marine Technical Advisor Kristina Hillock says “Pathologists were unable to determine whether the male fetus died as a result of congenital abnormalities, disease or due to a difficult birth. The most likely cause of death for the mother is blood poisoning due to the decomposing fetus”. Pathology reports noted that “the differing degrees of decomposition between the mother and fetus in this case tell us that the fetus died at least several days before the female did. Māui dolphin are the rarest and smallest of the world’s 32 dolphin species and a recent estimate of the population indicated that there are approximately 57 to 75 individuals over one year of age. It was apparent that the calf had died several days before the mother, causing the blood poisoning.įurther testing is needed to determine whether the dolphin is a Māui or Hectors dolphin, in any case this is a significant concern that a female dolphin of breeding age has died. A necropsy by Massey University’s veterinary pathology specialists was conducted to determine the cause of death on Wednesday and found that the dolphin was pregnant.

Dolphin fetus