This summer, I observed several large black birds nesting on small islands and shoreline of the St. Lawrence River near the Thousand Islands, while visiting my in-law’s boat. Upon later research, I discovered that these were double-crested cormorants, and that their presence has become a widely contested and controversial issue. Rapidly increasing population and extended range of the cormorant have been observed in the St Lawrence River region, with record-breaking numbers, in recent years (Wolf, 2018). According to the Ottawa Riverkeeper (2021), the species’ native range was originally restricted to the Great Lakes, but has since extended to the St. Lawrence River and is now found in the Ottawa River watershed.
Many claim that cormorants significantly decrease fish populations and degrade terrestrial habitats; colonies have even been responsible for destroying entire island ecosystems (OFAH, 2021). The Minister of Natural Resources and Forestry, in an attempt to “strike a healthy balance in local ecosystems” (p.1), has announced a cormorant hunting season in Ontario that will run annually from September 15 to December 31 (Natural Resources and Forestry, 2020).
Conversely, others disagree with the claims made about the species and strongly oppose population control. Some experts believe the decision to hunt is not based on scientific justification, stating that the death of vegetation by cormorant colonies is a natural process that is part of the complex ecology and contributes to biodiversity (Blaise, 2020).
I believe that climate change plays a role in the extended range and increased population of the cormorant, as warmer waters and more exposed shorelines have opened up new habitats. This situation is very delicate as the cormorant is a migratory species, so while it may be deemed a 'nuisance' in the Great Lakes and St. Lawrence region, culling numbers in Canada could have impacts on global populations and ecosystems in other parts of the world (K. Alambo, personal communication, September 24, 2021).
References
Blaise, K. (2020). Changes to Ontario’s Wildlife Law Threatens Science Based Decisions and Conservation. Ontario Nature. Retrieved from https://ontarionature.org/cormorant-legal/
Natural Resources and Forestry. (2020). Ontario Taking Steps to Protect Fish and Wildlife Habitat. Ontario Newsroom. Retrieved from https://news.ontario.ca/en/release/57855/ontario-taking-steps-to-protect-fish-and-wildlife-habitat
Ontario Federation of Anglers and Hunters (OFAH). (2021). Cormorants. Retrieved from https://www.ofah.org/issues/cormorants/
Ottawa Riverkeeper. (2021). Invasive Species. Retrieved from https://ottawariverkeeper.ca/what-we-do-2/initiatives/watershed-health-assessment-and-monitoring/invasive-species/
Wolf, M. (2018). DEC Sees Record Year for Cormorants. NNY360. Retrieved from https://www.nny360.com/news/dec-sees-record-year-for-cormorants/article_e21825f3-ad38-52cd-b187-40a3ec483c4b.html
Observations From Members 
