Date of Award
Open Access Thesis
Master of Science (MS)
The critically endangered North Atlantic right whale (Eubalaena glacialis) consistently visits five major habitats throughout the year; however, they are known to visit additional habitats. This project examines the role of Jeffreys Ledge as an additional habitat of importance for this species by investigating three aspects of its distribution and ecology. I first addressed the relationship of Jeffreys Ledge to a known significant right whale feeding ground, Cape Cod Bay, by quantifying the movement of right whales between the two habitats and comparing demographic characteristics of right whales seen in these habitats. Secondly, I measured the quality of the zooplankton resource in Jeffreys Ledge and the relationship between plankton characteristics and whale sightings in this habitat. Thirdly, I examined the spatial distribution of right whales, and the relationship between right whale sightings and bathymetric characteristics in Jeffreys Ledge. While the populations of whales in these habitats do not appear to be demographically distinct, the results suggest that there is more movement between habitats by males than by females during the first few months of the year. Although there was no observed relationship between sightings per unit effort (SPUE) and energetic density of zooplankton prey resource in Jeffreys Ledge, low caloric density is a significant predictor of whale absence in the region. The lack of a relationship between SPUE and energetic density is likely the results of the zooplankton sampling methodology. Spatial analysis identifies a hot spot of high SPUE which changes in size, location and intensity throughout the study period, and both a binary logistic regression and a generalized linear model support a relationship between whale sightings and depth in the habitat. Results of this project highlight the need for more precise plankton sampling in the region as well as the need for concurrent survey efforts in multiple habitats. Assessing the importance the Jeffreys Ledge habitat to the right whale will help conservation managers to better allocate resources and mitigate the effects of anthropogenic threats to this highly endangered species in this region.
Longley, Kathryn, "Investigating the Role of an Understudied North Atlantic Right Whale Habitat: Right Whale Movement, Ecology, and Distribution in Jeffreys Ledge" (2012). Graduate Masters Theses. 105.