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young humpback whale dies of chronic entanglement
Shortly after sunset on July 26th , a call was received via IFAW’s stranding hotline notifying its marine mammal rescue team of a live humpback whale swimming in Wellfleet Harbor on Cape Cod, MA. With an evening response impossible, a team of responders arrived at morning light to find the animal had succumbed to its injuries overnight.
Further analysis revealed definitive signs of entanglement in line. A dismal reality, yet one that is all too common with regards to the fate of a spectrum of marine mammals, from seals to humpback whales, to the critically endangered North Atlantic right whale.
(Warning, some of the photos are graphic, but do depict findings discussed below. The lines seen in the photos were placed on the tail/flukes to tow the animal out of the area or further examination and were not present on the animal when the animal initially stranded.)
Discovered in an area known for strandings, the humpback showed evidence of deep wounds and emaciation, and that it likely died as the result of long-term—or “chronic”—entanglement.
The young female weighed approximately 7900lb (3583kg) and measured 24 feet (745cm) in length. For perspective, a whale of this length should average 13,500 pounds (6161 kg)—roughly double what this young whale weighed. In addition, its scapula and skull showed prominently below an extremely thin layer of blubber. This all points to the fact that chronic entanglement often leads to starvation in whales either by impeding feeding or making it more difficult for them to swim.
A thorough necropsy (animal autopsy) was conducted by a team of experienced biologists and veterinarians, at which time external and internal observations were photographed, measured, and noted for official record. We found obvious signs of trauma including deep wounds on its flukes and tail stock (peduncle). A specific cause of death is only assigned when the evidence clearly and definitively supports the conclusion, and in this case it was clear.
Since January 2016, humpback whales in the Northeast U.S., from Maine to Virgina, have been experiencing an Unusual Mortality Event (UME), meaning that a larger than average number of humpbacks are dying in this area. What is perhaps even more striking is that half of the whales examined show evidence of human interaction, either through vessel strike or entanglement.
IFAW has a long history of working on such issues related to both entanglement and vessel strikes, most notably with the critically-endangered North Atlantic right whale. We have assisted in disentanglement efforts and led necropsy efforts for such lethal cases in recent years. Regardless of the species, we remain committed to finding a solution and protecting the future for these magnificent animals.
While this work is complex and heart-breaking, we believe that every individual animal’s life is crucial to the whole of marine conservation. Our findings help us to better understand what is happening and why. Through the process of documenting and learning, IFAW has been able to work in policy and industry realms to find long-term solutions and prevent future interactions and deaths from happening.
There will no doubt be more entangled whales—humpbacks or otherwise—and many more animals in need of help. But we can all take collective action to turn this situation around.
Activities conducted under a federal stranding agreement between IFAW and NMFS under the MMPA
This was a multi-day effort that would not have been possible without the support from the Town of Wellfleet (DPW, Police and Harbor Master Departments), Winkler Crane, Town of Dennis Transfer Station, the Center for Coastal Studies, Whale and Dolphin Conservation, NOAA Greater Atlantic Regional Fisheries Offices, and IFAW volunteer responders and interns.
Our colleagues at the Center for Coastal Studies, who maintain a catalog of humpback whales in the western North Atlantic, are working to identify the individual whale, but a match has yet to be made. The poor body condition, identifying marks, and age of the animal enabled researchers to determine this animal is not one of the three whales recently sighted off Plymouth, MA.
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