Question:

What was the effects of the DWH oil spill and associated response activities (e.g. 200 million gallons of oil, 1.8 million gallons of dispersant, in situ burns, and hundreds of additional boats) on the foraging behavior of approximately 1000 sperm whales residing in the Gulf of Mexico?  Sperm whales are extremely efficient deep-diving marine predators, tending to feed on patches of prey that they locate with a mixture of clicks and creaks (Watwood et al. 2006). Dive profile records indicate that sperm whales in the Gulf of Mexico forage near 520 m depth in the water column (Watwood et al. 2006). Sperm whales feed along and about the 1000-m isobath in the region between Mississippi Canyon and De Soto Canyon (Jochens et al. 2008) (Figure 1.). They may consume several thousand kilograms of prey a day (Best 1979) comprised of about 1000 individuals (Clarke et al. 1997). Given their food consumption needs, their prey resources are likely a critical factor driving their distribution and foraging behavior in the Gulf of Mexico during the spill.

Datasets:

I have requested satellite tag data form Oregon State University Marine Mammal Institute. Fortunately, OSU scientists tagged and tracked sperm whales prior to the spill, during, and after. However, there is a good chance I will need to change projects because I do not currently have datasets for analyses.

Hypotheses:

I hypothesize that the availability of sufficient prey resources required to meet the caloric needs of resident sperm whales outweighed the chaos created by the oil spill and response activities.

Approaches:

I am not sure of the best approach, but hope to get some assistance from my peers. My goal is to measure any shift in foraging areas and to complete trend analysis, hot spot analysis, and cluster analysis of foraging areas prior to, during, and several years post spill.

Expected Outcomes:

It would be ideal to detect patterns that are predictive of food web disturbance that ultimately predict the response to sperm whales to disturbance.

Level of preparation:

I have moderate experience with ArcMap and some experience with spatial analyses with ArcMap. I have an understanding of basic statistics and statistical software Minitab. I do not have any experience with R or Python.

References:

Best, P.B. 1979. Social organization in sperm whales, Physeter macrocephalus. Pp. 227-289 in Behavior of marine animals, Vol. 3, edited by H.E. Winn and B.L. Olla. Plenum, New York.

Clarke, M.R. 1997. Cephalopods in the stomach of a sperm whale stranded between the islands of Terschelling and Ameland, southern North Sea. Bulletin de 1’Institut Royal des Sciences Naturelles de Belgique, Biologic 67-Suppl 53-55.

Jochens, A.E. and D.C. Biggs, editors. 2006. “ Sperm whale seismic study in the Gulf of Mexico; Annual Report: Years 3 and 4.” OCS Study MMS 2006-067. 111 pp., Minerals Management Service, Gulf of Mexico OCS Region, U.S. Dept. of the Interior, New Orleans, LA.

Jochens, A., D. Biggs, K. Benoit-Bird, D. Engelhaupt, J. Gordon, C. Hu, N. Jaquet, M. Johnson, R. Leben, B. Mate, P. Miller, J. Ortega-Ortiz, A. Thode, P. Tyack, and B. W. 2008. 2008. “Sperm whale seismic study in the Gulf of Mexico: Synthesis report.” OCS Study MMS 2008-006. 341 pp, Minerals Management Service, Gulf of Mexico OCS Region, U.S. Dept. of the Interior, New Orleans, LA.

Watwood, S.L., P.J. Miller, M. Johnson, P.T. Madsen, and P.L. 2. Tyack. 2006. Deep‐diving foraging behaviour of sperm whales (Physeter macrocephalus). Journal of Animal Ecology 75(3):814-825.