Humpback Whales/Ballenas Jorobadas

 (Megaptera novaeangliae)

Although humpback whales are found pretty much all over the world and are one of the most studied species of large whales, there are only a couple of scientifically documented births and to the best of our knowledge no one has seen mating occur (it has not been scientifically documented). We therefore don’t know the details of the mating ritual or when it occurs (if during migration, or at the breeding grounds, or both).  Learning more about their overall reproductive system will therefore get us closer to understanding what measures would be more effective in conservation.

In collaboration with Whale Trust we are studying the hormone levels in humpback whales (progesterone, testosterone and cortisol) and comparing them to the different male and female reproductive behaviors exhibited by humpbacks during the breeding season in Maui, HI. Progesterone in females indicates either estrus or pregnancy, while testosterone is a predominantly male hormone responsible for reproduction processes in males. Cortisol is a hormone that can indicate relative levels of stress the whales are experiencing during breeding season, although the specific cause is hard to determine.

With this study we are looking to help answer questions about humpback whales’ reproduction, such as for example what is the specific role of whale song in the reproductive process (we know that male humpbacks’ song is related to reproduction, but we don’t yet know exactly why they sing). By understanding how reproductive hormones and behaviors are related, we will know more details about the breeding system and can use this information when implementing management strategies.

While globally humpback whales seem to be doing well, there are a few sub-populations that are not doing so well. These include the Arabian Sea, Oceania, and western North Pacific. For more information please visit The IUCN Red List of Threatened Species. By learning more about humpbacks in areas such as Hawai’i, we can then apply the knowledge to undertake conservation initiatives for the threatened populations.

YiyiHumpbackPhoto by Jim Darling

Under NMFS Permit #13846.

En colaboración con Whale Trust estamos investigando

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