Question of the monthIn an interview with Janie Giard, head of great whale research projects for the Group for Research and Education on Marine Mammals (GREMM), Whales on-line asked her the following question: Where are the fin whales of the Estuary?J. G. : Fin whales were abundant in the St. Lawrence Estuary in the 1980s and 1990s. Research and tour-boat operators will tell you that during this period it was not uncommon to see groups of 10 to 30 fin whales at a time. These giants of the sea were so plentiful, surfacing side by side, that naturalists were heard using phrases such as, “Look at the bouquet of blows!” Up to forty different animals could be identified in a given season. As well as being present in large numbers, their distribution patterns were also well known to anyone who spent time on the water; these cetaceans regularly visited specific zones. Then, from 2000 to 2005, the model changed: fin whales were not as bountiful and they were more widely distributed over a vast territory. A scant dozen fin whales were identified each year during this period. Inevitably, following these lean years the obvious question, “Where are the fin whales of the Estuary?” was on the lips of researchers, tour operators and even regular visitors to the area. To date, nobody has a definitive answer to this question. However, there are clues that indicate a change has taken place in the environment at the head of the Laurentian Channel. For example, the temporal sampling series measured by Michel Harvey of the Maurice Lamontagne Institute (Fisheries and Oceans Canada) indicates a major decrease in macro zooplankton in the St. Lawrence Gulf and Estuary of as much as 70 percent between 1994 and 2003. Researchers believe this decline could be due to climate change and variations in the characteristics of the different water layers. Furthermore, while krill represented 80 percent of total macro zooplankton in 1994, it corresponded to only 40 percent in 2003. Simultaneously, a new species began appearing in the St. Lawrence in large quantities in the early 1990s. The species in question, a cold-water, Arctic amphipod known as Themisto libellula, has not gone unnoticed: from 1994 to 2003 it represented between 2 and 45 percent of biomass depending on the years. It is possible these changes in the communities that inhabit St. Lawrence ecosystems—a major feeding ground for cetaceans—could have long-term effects on whales. Yet, if many of the Estuary’s fin whales were absent from this area between 2000 and 2005, where were they? A recent study comparing fin whales identified off Halifax, in the St. Lawrence and in the Gulf of Maine concluded that, as summer approaches, fin whales are likely more flexible than previously thought when it comes time to choosing where to feed. So, has Grand Galop, a fin whale first identified in 1986, simply chosen a new feeding ground? Could he be out in the Atlantic or even on our doorstep in the Gulf of St. Lawrence? And what of Perroquet who had visited the Estuary every season since 1990 and who brought with her a calf on three separate occasions? Will we ever see her again? The St. Lawrence Estuary has been a whale-watching destination of choice for nearly 30 years. A wide variety of species abound here year after year, to the delight of visitors. But the scarcity of fin whales in the Estuary gives pause; this intriguing species is likely a messenger of changing ecosystems and warrants the interest of researchers. Update: The 2006 distribution pattern took everyone by surprise: fin whales were plentiful and closely packed at the head of the Laurentian Channel, just as they were in certain years preceding 2000. What happened in 2006? What will happen next year? An intriguing mystery that is likely linked to the ecology of this species’ prey, which include krill, capelin and possibly other species of plankton and fish. Researchers are on the case. To be continued… |