All along, researchers have been laboring to reveal the remarkable symbiotic relationships that remoras, sometimes called suckerfish, share with their much larger hosts, including humpback whales. These small fish hatch in the open ocean and utilize a unique suction cap on their heads to cling to larger marine animals. In turn, remoras enjoy this commensal relationship by receiving access to food and transportation. Meanwhile, scientists get important baseline understanding of the health of whale populations up and down Australia’s east coast.
Every winter, more than 30,000 humpback whales embark on one of the most spectacular migrations on Earth. They migrate 10,000 kilometers round-trip over the waters of eastern Australia. This migration season is one to watch, especially by researchers on Queensland’s Gold Coast. Dr. Olaf Meynecke, a leading researcher in this field, has attached suction-cup cameras to the backs of these colossal creatures to study their behaviors and interactions with remoras.
The Unique Lifestyle of Remoras
Remoras have a relatively long life cycle of about seven years. Relatively quickly, though, they can change hosts, jumping from one whale to another as they travel and feed. These guys mainly dine on sea lice—parasites—as well as dead skin sloughed off by their larger swimming partners. Remoras have a very productive life under this parasitic relationship. Simultaneously, it serves whales’ interests by allowing them to purge the ocean of bothersome nuisances.
Dr. Meynecke noted the significance of this interaction: “We always talk about how important whales are for the ocean, and here they are being a bus, picking up all these travellers and moving them up and down the coast.” This relationship is a perfect example of keystone species and the interconnectedness of marine ecosystems, showing how one species can support another.
Remoras hitch ride on humpback whales as a way to find a hospitable home. This defuses dangerous currents and protects them from harm while on the move. Dr. Meynecke describes it as a strategic adaptation: “They’re finding their sweet spot where there’s the least amount of current and then they cruise with the whale — once they attach, they’re pretty safe.”
Insights into Whale Health
With remoras, their abundance can tell you how healthy the populations of the whales you’re hitching a ride with are. Dr. Meynecke has witnessed schools of fish circling the fins of humpbacks. For one, he observes that remoras are preferentially attracted to whales that are sloughing more skin than average, a potential sign of stress. This collaborative partnership provides invaluable data to researchers such as PhD student Sarah McCulloch, who are helping us better understand whale health and behavior.
They have no idea what it is you’re trying to research,” McCulloch explained. What he was emphasizing was the hit or miss aspect of looking for whales. These observations almost always result in unexpected discoveries regarding the health and dynamics of whale populations.
So, according to McCulloch, humpback whales in Australian waters are doing better than ever. “The whales are subsidizing … an entirely different species,” she said. This symbiotic relationship underscores how diverse life forms can coexist and rely on one another in the ocean’s intricate web.
