Determining pregnancy status of extant and ancient whales by quantifying progesterone in blubber biopsies and bone

• Main Author: Sheridan, Mackenzie L.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2004
• Subjects: Eubalaena glacialis; Megaptera novaeangliae; minke whale; North Atlantic
• Online Access: https://research.library.mun.ca/12305/; https://research.library.mun.ca/12305/1/Sheridan_Mackenzie.pdf

This thesis had three major objectives: 1) to determine the most appropriate method for the short-term storage of blubber biopsy samples for hormonal analyses, 2) to determine whether or not progesterone could be quantified in blubber biopsy samples from free-ranging North Atlantic humpback (Megaptera novaeangliae) and North Atlantic right (Eubalaena glacialis) whales in order to determine pregnancy status, and 3) to determine whether or not immunoassayable progesterone could be quantified in ancient whale bone samples. In order to determine the most appropriate method for storing blubber biopsies for hormone analyses, samples were collected from a known pregnant minke whale (Balaenoptera acutostratus) post-mortem and stored frozen for 2 months under different conditions- in ethanol, 100% dimethylsulfoxide (DMSO), 20% salt-saturated DMSO, and frozen. Biopsy samples stored in ethanol yielded less than 10% of the progesterone concentrations of those in the other three storage conditions (p < 0.05). However, once extracts of both the blubber samples that were in ethanol and the ethanol liquid fractions were combined, progesterone concentrations were comparable to those of the other three storage conditions (p > 0.05). Progesterone concentrations were determined from blubber biopsy samples of free-ranging humpback (n = 32) and right (n = 17) whales in order to determine pregnancy status. We hypothesized that females pregnant at the time of sampling would have elevated blubber progesterone concentrations. Thirteen of 21 female humpbacks (62%) were resighted the year following sampling. Three females with elevated blubber progesterone concentrations and one with a moderate progesterone concentration were observed with calves. Seven mature females (two with elevated blubber progesterone concentrations and four with moderate blubber progesterone concentrations) were observed without calves, introducing the possibility of neonatal mortality, spontaneous abortion, pseudopregnancy, or possibly failure of the ...