Why Are Humpback Whales Eating More Crab And Snails?

A recent article shows how a group of Humpback Whales in the Gulf of Maine seem to have learned a strange new feeding technique from each other; a unique feeding method called Lob Tail Feeding and was only discovered in the region in 1980. Humpback whales feed off of discarded fish and small crustaceans that become their meal. The best time for Humpback whales to feed this way is in summer when they are most active. Whales will even go so far as to attack sharks that come too near their feeding areas. Humpback whales learn the feeding technique almost instantly and have been known to copy it quickly. They even have a similar strategy during their annual migration, wherein they will regroup and feed in different directions in search of krill.

For decades, scientists and marine biologists have been involved in attempts to explain what the social learning of behaviour is and what its importance is to the life of the species. Through many research programs and studies, scientists have been able to develop theories about the reasons behind some of the unique behaviours exhibited by these amazing sea creatures. These theories include Killer Whales’ hunting and feeding patterns, the communication among individual sperm whales and the importance of colony activity for the maintenance of the Humpback whale population as a whole.

In this new study, a team of researchers led by Dr. Will Rixson, PhD came across a surprising feeding trend amongst humpback whales while conducting online research on the ocean’s most abundant marine organism, the Sea Cucu Unda. This organism occurs at the very end of the strand and is normally so abundant that it is the only one of its kind on the ocean floor. Rixson noticed that when he chose certain areas to conduct his research, the amount of fish in the area decreased. The decrease was so drastic that he realised that the change could be linked to a particular humpback whales food chain.

Although scientists are yet to fully understand the complex interactions between individual marine animals and the ocean environment, they have already identified a number of food choices that seem to be more common across species. Paciferal prey is one such food group and includes fish, crabs, small squid and octopus. The increasing global demand for seafood has also meant that Paciferal species are now extremely vulnerable. Recent records show a dramatic decline in the numbers of bluefish, yellowfin tuna and albacore tuna due to overfishing. The loss of these apex predators has meant that humpback whales now find themselves relying heavily on their diet of highly specialized scavengers such as ciscoes, squids, chubs and other small pelagic animals.

In addition to this, other suggestions as to why humpback whales have become dependent on their diet of crabs and other invertebrates can be put forward. One of the most worrying suggestions is that the increased consumption of scavenging may mean that there has been an increase in the build up of entanglements. Entanglements occur when large marine creatures entangled themselves in other smaller animals, often including crabs and even birds. This can cause significant damage to the delicate gill membranes, making it difficult for humpback whales to breathe properly. The addition of more powerful sonar, or fish-eating sonar, may have been responsible for the rapid increase in entanglements over the last few decades.

Other suggestions put forward as to why whales are consuming more crab, snails and other ocean animals include the fact that humpback whales are directly interacting with the oceans, meaning that they are being subjected to direct physical contact. In turn, the food sources that these animals are eating have been placed in direct proximity to whales. All of this has been seen in the Southern Pacific Ocean, where many entanglements between marine animals have occurred in the past decade.