A young North Atlantic right whale that was seen near Massachusetts about two months ago is now at the center of a difficult rescue effort after being spotted with fishing gear tangled in its mouth in Canadian waters. With the population down to roughly 380 whales, one more entanglement matters. What happened? Fisheries and Oceans Canada took to social media to reveal that a June 8 aerial survey located the 5-year-old male in the Gulf of St. Law…