Double-crested cormorants…

Double-crested cormorants are in invasive species in Ontario and are likely having a serious detrimental effect on native aquatic habitats and aquatic wildlife species where they compete for food resources and nesting cover/habitat. Native fish populations are most certainly impacted in fish rearing habitats such as wetlands and shallow near-shore lake environments. As a biologist I am seeing the cormorants in spring and summer months foraging in small wetlands in rural Ontario, away from what we traditionally think of as cormorant habitat. This may be because the species have reached the carrying capacity for their species and competition for food has pushed them to interior wetlands more and more over the years. They can also consume large volumes if our native fish stocks in all areas where they live.

It is possible that cormorants may have a role to play if other aquatic invasives take off in Ontario lakes. I think of the Asian carp species now at large in the great lakes. More research is likely needed on this but my opinion is that double-crested cormorants need to be reduced in numbers to something much more sustainable than at present. Hunters may have a role to play in reaching such a goal.