We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Microplastic ingestion and diet composition of humpback whales from the Northeast Pacific Ocean
Summary
Scientists studying humpback whale poop found these ocean giants swallow over 400,000 microplastic particles a day while feeding on krill near Vancouver Island, yet this only adds up to a tiny fraction of their body weight, and most of the particles were harmless cellulose fibers (a plant-based material), not harmful plastics. While the whales themselves seem to face low risk, this research matters because it shows just how deeply microplastics have infiltrated ocean food chains, the same food chains that produce the seafood many of us eat.
The rapid recovery of humpback whale populations in the North Pacific, following decades of intense commercial whaling, represents a conservation success story. However, the future population growth and stability of this enigmatic species is now threatened by a growing list of anthropogenic stressors, including plastic pollution. My thesis aimed to quantify the level of microplastic (MP) ingestion among humpback whales foraging near the Juan de Fuca Strait, via opportunistically collected fecal samples. A total of 20 humpback whale fecal samples were collected during the summer of 2024, yielding an average of 24.4 ± 16.4 MP/g (dry weight), the majority of which were regenerated cellulose fibres. Stable isotope analysis and whole genome sequencing indicated that the sampled whales were primarily feeding on krill, enabling estimation of consumption rates which, combined with fecal MP concentrations, resulted in an average ingestion of 418,227 MP particles per day (95% CI: 402,191 - 436,172). This corresponds to an ingested mass of 0.37 g of MP per day (95% CI: 0.36 - 0.39), representing approximately 1.3×10^−6 % of the body mass of a 30 tonne humpback whale. Given the low estimated mass of ingested MP and scarce toxicological effects of regenerated cellulose, the risk to whales in this study appears relatively low. However, this finding is context-specific, and smaller particle classes such as nanoplastics, which were not assessed here, may have different bioavailability and toxicological implications. Nevertheless, these findings provide insight into the toxicological landscape of coastal food webs and can help inform future species risk assessments in Canadian Pacific waters.