How scars tell the story of our whales
If you’ve been onboard Elding’s tours or followed our blog you know that our research team does its best to identify every whale and dolphin that we encounter. We can do this because each individual has their particular characteristics; they all have their own personality and unique external features through which we recognise them. Sometimes, the marks even reveal things about the whales that we don’t directly get to observe during our tours: they can show us the scars from fights with conspecifics, attacks from predators, pathologies, or human impacts. In this post we highlight some of those prominent markings and introduce you to some of the whales that have survived to tell their story through their scars.
Tough Pella – Propeller strike
The scars of Tough Pella don’t require a lot of explanation: they clearly show the enormous impact the blades of a boat propeller have had on his back. We don’t see many whales with injuries as severe as Tough Pella, but that could also be because not all of them survive such a traumatic incident. Tough Pella, however, was spotted in Akureyri in 2017 and also in 2018, so it’s great to see that this humpback whale was able to survive. There are no global estimates for how often propeller strikes occur, but with the increasing ship traffic we know that these types of incidents are becoming more frequent.
Nettie – Fishing gear
Fishing gear is a serious problem for cetaceans, and there are estimates that approximately 50% of humpback whales become entangled in fishing ropes at some point in their lives. In 2015, our team got to know one of those entangled whales very well, when Nettie was swimming in the bay for many days with a fishing rope around her fluke and flank. We were able to call the coast guard and send out a rescue team to help release this humpback whale but she will carry the deep indentations of the tight rope for the rest of her life, as many other whales do.
Líney - Orca rake marks
Thankfully, not all markings come from human impacts - some have a natural cause. The bright white rake marks on Líney, for example are the evidence of an orca predation event. Icelandic orcas are most probably not the culprits as they generally eat herring (once in a while they’ll eat harbour porpoises and seals). Icelandic orcas have on occasion been observed going after baleen whales, however this occurs rarely and our guess is that this orca attack occurred sometime during Líney’s migration to or from her breeding grounds in warmer waters. We are happy she made it back to Iceland, and she looks like a very healthy and happy humpback whale who we often see playing around the boat and showing off her acrobatic behaviours since we first encountered her in April of this year.
Aura – Lamprey or cookiecutter shark scars
Many whales have white circular markings on their body, such as this minke whale who we have seen from 2007 until 2018 and that we have called Aura. These are most likely the scars from lampreys who often attach themselves to minke whales and humpback whales to feed on their flesh. Sometimes we also observe bitemarks from cookiecutter sharks, but they mainly live in warmer waters so the wounds are often already healed when the whales reach Iceland. Some researchers in other parts of the world have used the freshness of cookiecutter sharks as an indicator of how recently the whales had been in warm waters to find out more about their travelling speeds.
Neila – Barnacle scars
Many humpback whales are covered in barnacles around their head, dorsal fin, peduncle and fluke. The large body that the whale often manoeuvres through plankton-rich areas is a great vehicle for filter-feeding barnacles that attach themselves into the humpback’s skin. Although the barnacles only live on the whales for approximately one year the scars they leave when they fall off seem to be relatively permanent. Neila shows off some of those prominent round, white scars in the middle of her fluke. The barnacle scars are in fact the reason for her name: they remind us of an alien face, which is the reverse of Neila. She has often showed us her beautiful characteristic fluke and Neila is one of our most curious whales so we are happy to have gotten to know this whale since her first visit to Faxaflói in 2021.
Droplet – Diatoms
Some scars are less permanent than others: yellow pigmentation on many of our humpback whales’ flukes appears and disappears over consecutive years that we see them. This yellow colouration is made up of diatoms, a type of phytoplankton that forms a film on the skin. Although the pigmentation is very conspicuous and distinct over the short-term, we don’t use it for our photo-identification research because it isn’t permanent. The yellow still makes for a beautiful colourful addition to the otherwise black-and-white flukes, for example on Droplet, who we saw for the first time in 2021.
Although the markings that we see on these whales often hint at impactful events and are therefore not always positive, for our research they are very helpful. They tell us what problems the whales face even when we can’t have our eyes on them at all times, and they allow us to identify and keep track of individuals to further our understanding of their biology and ecology. We are thankful that we can observe these individuals and get to know more and more about them through their unique scars and markings.
By Eline van Aalderink