Indeed. While most of the time a fin sighting would be harmless, that area is within territory covered by great white sharks. In 2021 a woman swimming at Margaree Island was bitten by a great white that likely mistook her for a seal.
As waters warm, mako and great white sharks have been spending more time close to shore over the past decade.
Just like with any animal at the top of the food chain, it’s better to use caution than to tempt statistics.
Two books I found really useful at the time:
The Little LISPer by Daniel P Friedman
Applied Cryptography by Bruce Schneier
Both are rather niche, but helped me understand general computing and design concepts.