Distribution of North Atlantic Right Whales in Canadian Waters

North Atlantic right whales are known to calf in the waters off of the southern USA in winter, then to migrate north into Canadian waters where they spend much of the year feeding. Portions of the population aggregate seasonally in two high-use habitat areas in Scotia-Fundy waters. During the summer and fall in recent years, for example, approximately two thirds of the population has aggregated in the lower Bay of Fundy. Historically (prior to 1993), and beginning again in 2000, a portion of the population aggregated for feeding in the vicinity of Roseway Basin during the same time period. Smaller aggregations and individual right whales are seen over a very wide area.

Monitoring activities in Canadian waters have been restricted, for the most part, to the high use areas (especially the lower Bay of Fundy), during the summer months. While DFO has, for several years, funded a limited amount of surveillance (air and vessel) in the spring and autumn 'shoulder seasons' and over a wider area (e.g. Scotian Shelf), there has been insufficient documentation of the spatial and temporal distribution of NA right whales in Canadian waters. We do not know, for example, the duration of right whale occupation of the high use (conservation zone) areas in the Bay of Fundy and Roseway Basin. Nor do we know much about the distribution of right whales beyond the conservation zone.

The project will provide direct information on distribution and movement of right whales. This information is of direct relevance to assessment of stock status, and is an important prerequisite to evaluation in relation to management activities and potential mitigation measures (in relation to interaction with vessels and fishing activities for example). This project includes three sections: the revision and evaluation of survey approaches for Right Whales, the enhanced surveillance of Right Whales in Canadian waters, and the development of modified surveillance methods.

Revision and evaluation of survey approaches:
Several organizations in both Canada and the USA undertake surveillance and surveys of right whales using a variety of methods. These methods have been reviewed, compared and evaluated based on their objectives, methods, and results in an effort to improve the monitoring of right whales in Canadian waters.

Enhanced surveillance of right whales in Canadian waters:
In recent years a limited amount of surveillance has been undertaken to document the presence or absence of right whales, and to undertake photographic identification of individual right whales during the 'shoulder seasons' (June and October/November). The same holds true for the Roseway Basin area (June through October). There is considerable need to extend surveillance through dedicated surveys and opportunistic surveillance to better define the distribution (spatial and temporal) and abundance of right whales in Canadian waters. Air and vessel surveillance will be undertaken to complement and extend the intensive work being done already by others. Surveillance will include photo documentation of individual right whales, where possible, for identification by the New England Aquarium.

Development of modified surveillance methods:
Dr. Alex Hay and collaborators at Dalhousie University are developing a system of using bottom-mounted hydrophones to detect and locate right whales. The system has been deployed for short periods during the summer. Hay and colleagues are developing algorithms for detection of right whale sounds, removal of background sound, improved sub-sampling and storage of information and determination of position from hydrophone array. A prime objective of this development has been the location of whales in relation to vessel traffic, but it is thought that the hydrophones are potentially useful in documenting the presence of whales during shoulder seasons. The SABS Species at Risk group collaborated with the Dalhousie team to test the use of the hydrophone system to document the duration of right whale occupation of the Bay of Fundy conservation zone in Autumn 2002.

Distribution of North Atlantic Right Whales Related to Abundance and Distribution of Copepods in the Bay of Fundy:
A significant portion of the North Atlantic right whale population is known to gather in the Grand Manan basin located in the lower Bay of Fundy, as well as Roseway Basin on the southwestern Scotian Shelf during the summer and fall. It is postulated that they aggregate in these areas due to a high abundance of copepods on which they feed, and recent studies of the Bay of Fundy right whale herd have documented that the whales there are feeding on a dense layer of stage V calanoid copepods. These copepods, mainly Calanus finmarchicus, are believed to accumulate in this layer during their diaphanous phase due to the hydrographic nature of these areas, i.e. relatively deep basins. The copepodite stage V (CV) C. finmarchicus enters this phase to overwinter in the deeper water, relying on stored lipid reserves, returning to upper water layers in spring to mature into adults and breed. It is likely due to this concentrated store of lipids that North Atlantic right whales appear to prefer feeding exclusively on CV C. finmarchicus when they are available. It has also been postulated that right whales actively seek out these areas of high copepod abundance so that they may accumulate a sufficient store of fat to last through their calving season in warmer southern waters, where their food supply may be limited.

A study, by Species at Risk intern Jeremy Wentworth, attempted to correlate the temporal and spatial distribution of whales and of copepods over the 17-year period from 1982 - 1998 in the North Atlantic right whales' traditional areas of aggregation, the Bay of Fundy and southwestern Scotian shelf. This time period was chosen as it is represented both in the DFO historical plankton data (the Larval Herring Program), and also right whale distribution data sets which begin around 1980.