Furthermore, this information may also be useful to the local whale-watching operators based in Tofino. There were four objectives of this research project. The first objective was to establish an inventory of the variety of different gray whale prey species present in Clayoquot Sound. The second objective involved quantifying intraseasonal and interseasonal changes in the densities, the biomass, and the sizes of organisms in the invertebrate populations. The third objective involved evaluating the role of prey density in patches, as well as mean prey abundance, in shaping food-web relationships between invertebrates and whales.
Gray whales require some minimum prey biomass density for efficient foraging.
Although prey may be locally abundant, if the organisms are diluted over a vast area and are not sufficiently concentrated in discrete patches, then the prey will be not be an available energy source for the whales. Consequently, there is an important ecological difference between prey density and mean prey abundance. Prey density in patches was determined from areas where foraging gray whales were present. These apex predators were used to reveal the locations of dense swarms of invertebrate prey. On the other hand, in the absence of feeding whales, the mean abundance of different prey species was quantified.