Yellow perch
Loons in the park have the highest levels of methyl mercury in their blood of any loons in North America, the result of bioaccumulation. This is reducing their reproduction rates. Yellow perch, 10–15 cm long, is their main source of food, and these have been found to have more than twice the mercury level than loons from neighbouring New Brunswick. After years of research, the ultimate source of the mercury remains unknown. Mercury is present in many fish across Nova Scotia, and there are province-wide advisories on all species, except rainbow trout.