Corsair is a female that can be recognized by her rather unique S-shaped right chevron. Her dorsal fin is quite sharp and pointed. From the left side, she can be identified by subtle scarring behind her chevron. In 2006, Corsair was seen with a calf, but this one-time observation is insufficient to conclude whether or not it was indeed her own. Biopsies were performed during this encounter that might allow us to genetically match these two individuals. According to skin samples collected, there are approximately as many males as there are females in the Estuary. Males arrive in the region a week or two before the females and remain there longer, which is why it is the bulls that are most frequently observed.

Since her first visit to the St. Lawrence Estuary in 1991, Corsair has been identified only 6 years out of 25. This low rate of obser­vation makes this individual an occasional visitor. In the St. Lawrence Estuary, fin whales are grouped into three categories based on how frequently they have been observed since the year they were first identified in the Estuary: seasonal resident (75% and above), regu­lar visitor (40-75%) and occasional visitor (under 40%). The North Atlantic population being estimated at over 50,000 individuals, we can assume that there are summer feeding grounds other than the St. Lawrence where the occasional and regular visitors feed. In Canada, the most common areas are off Nova Scotia and Newfoundland. Elsewhere in the northwest Atlantic, fin whales are found off the US east coast and in the Bering Sea. However, very few data have been analyzed with regard to the links between the different populations. In the Gulf of St. Lawrence, the GREMM, MICS (Mingan Island Cetacean Study) and Fisheries and Oceans Canada maintain research efforts, including photo-identification and telemetry.