A Different Kind of Blues
Blue whales did not show up in consistent numbers in the St Lawrence in 2011. In addition, the few that did venture into these waters passed through quickly, perhaps not finding enough krill to merit more attention. The St. Lawrence was, however, filled with ravenous bluefin Tuna (Thunnus thynnus). This species has been found here in other years and 15yrs ago there was a fishery for this species in Baie des Chaleur bordering New Brunswick. This was the first time I had seen this many day in day out. They were spotted feeding at the surface as far up the St. Lawrence as Bergeronnes, on several days in the Mingan/Anticosti study area, however, they were most abundant off the eastern tip of Gaspé from August to late September. For the five weeks we searched for blue whales off eastern Gaspé , we mostly observed hoards of tuna racing after prey at surface. They seemed to be feasting on mackerel and herring that were abundant there. The bluefin seen at the surface were 1-2m long, however, at least one 600lb and an 800lb tuna were caught between Quebec and New Brunswick and shipped to Boston. The value of such fish from Boston to Tokyo-if that is where they ended up- is in the $100,000s and up. The bluefin can reach 1400-1500lbs or more than 650kilos, and live for 40yrs. While the ones that come to the Canadian waters breed in the Gulf of Mexico, satellite have shown that they can cross to Europe and back within the same year.
Why all this tuna in the St. Lawrence this year? More prey for them, due the demise of the cod, or simply warmer waters attracting more prey? Have we caused a food chain imbalance or was this simply a rare occurrence? Are there more tuna now that some restrictions have been placed on the tuna catch? It could be all these things and more. In fact bluefin tuna are found regularly in eastern Canadian waters off Nova Scotia and Newfoundland and in the southern St Lawrence, though not as common in the northern and western St Lawrence.
What if the tuna helped redress the balance in the food chain left vacant by the diminished stocks of cod? The smaller species have probably benefited greatly from the lack of cod over many years and could in fact be competing with blue whales for krill. Certainly a few more years of intense tuna foraging in the St Lawrence could benefit the tuna and the krill over time.
All that tuna and not a sushi stand in sight, which is just as well since we shouldn't be eating bluefin tuna due to severely depleted stocks.
Now as interesting as these tuna were to watch, we were off Gaspé to satellite tag blue whales. In fact we were met by the whale blues more than blue whales and saw only 8 during the five-week study period from mid August to late September. There were very few fins and minkes, and even humpbacks were not very abundant, though they had been earlier in the season.
When we saw blue whales they were moving quickly and did not stay long in the sector. Most seemed to pass through in a matter of hours then vanished. Only B271-a female regularly sighted in this region-was present over an extended period, but she was busy moving around looking for food that did not seem to be abundant. The result was that we only got one tag ready for deployment, but never had a real chance to place it on a blue whale.
We did see Chameau's 2002 calf see note in this newsletter section. And the following whales were briefly seen, the male B017-Scythe, B315, male B185-also observed in September in the Estuary, female B122 with a calf the 21st total since 1979, B349 known as Trauma due to a ship strike scar on its back, B249 and B260 both regulars. Only B185 appears to have spent more than a few days in the St Lawrence. A few others were sighted in the Estuary such as B268-Biombre a regular there and B311.
Off Mingan, where we have not seen many blues in the past 15 yrs, 5 individuals passed through quickly, seen only on one day each. Blue whales just did not seem to be finding what they needed as far as prey in the St Lawrence during 2011.
Fieldwork is this way at times and even with observers spread out in many parts of the St Lawrence no tags were deployed on blue whales this past season.