Scientists have analysed almost 30 years of data to discover how whales in the North Atlantic Ocean are learning to co-exist in a warming world. Rising temperatures and increased human activity in the North Atlantic Ocean have triggered “abrupt changes” in marine ecosystems, particularly for whales.
A new study published in Frontiers in Marine Science has examined how climate change is impacting the diet of three rorqual whale species living in the Gulf of St Lawrence (GSL) – a seasonally important feeding area for many whales.
Analysing 28 years of data, researchers found increases in resource partitioning among fin, humpback and minke whales. This is an ecological strategy where species divide resources such as food and habitat space to minimise competition, allowing them to co-exist. In layman’s terms, whales are becoming pretty good at sharing. Scientists collected more than 1,000 skin samples for the three types of whales to figure out what they were eating and which position they occupy in the food web. These samples were taken over three periods ( 1992-200, 2001-2010, and 2011-2019) corresponding to “shifts in environmental conditions.”
The results show that whales’ food in the GSL may be running low, but that whales can and might have already adjusted their diet to what prey is available.
Over time, all species included in the study moved towards more fish-based diets. Minke whales primarily fed on pelagic fish species but also consumed krill more frequently later into the study, while humpback whales largely relied on a few fish species, such as capelin, herring, or mackerel throughout the study period.
Researchers say this shift to new food resources may reflect a decrease in Arctic krill abundance.
Changing their diets and resource sharing aren’t the only thing that whales have perfected to adapt to the modern world. New research from the University of St Andrews found that “bubble-net feeding” has been crucial for humpback whales to recover in the northeastern Pacific, where populations had plummeted due to hunting. (euronews.)
