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Long-finned pilot whale (Globicephala melas): tissue lipid profiles
Citation
Walters, A, Long-finned pilot whale (Globicephala melas): tissue lipid profiles (2005) [Masters Research]
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Abstract
Blubber and muscle samples were collected from 63 long-finned pilot whales,
Globicephala melas, involved in a single mass stranding event on the east
coast of Tasmania (Reban Beach) in October 1998. This is the first time that
aspects of the foraging ecology and body condition of a complete group of
pilot whales have been reported from the Southern Hemisphere. Individuals
ranged in total length from 236 to 548 cm. Blubber thickness ranged from 30.7
to 74.0mm and blubber lipid content from 34.6 to 87.9%. No relationship was
found between blubber lipid content and blubber thickness, sex or reproductive
state. Both whole depth blubber samples, and blubber separated into three
distinct layers were analysed.. Lipid content in muscle from a subsample of
adult males, was found to be significantly different that found in blubber.
Muscle lipid content was significantly less variable than blubber lipid content,
and ranged from 1.2 to 13.2% (and on average comprised 3.3 ± 3.7% by
weight of lipid). The lipid composition of the blubber was dominated by
triacylglycerol (TAG). In comparison, muscle was comprised primarily of
TAG (57.3 ± 18.4%) and polar lipid (PL; 38.8 ± 16.8%). The FA composition
of the blubber was dominated by high levels of long-chain monounsaturated
fatty acids (LC-MUFA) (53.2 ± 3.7%) and low levels of polyunsaturated fatty
acids (PUFA; 5.9 ± 1.7%). Principal Components Analysis (PCA) revealed no
differences in FA composition of blubber between male and female pilot
whales, nor between non-lactating and lactating females. PCA did, however,
reveal clear separation between juveniles and adults, demonstrating significant
differences in fatty acid (FA) composition between age groups. FA driving the
age separation were 18:1ω9, 16:1ω7 and 16:0. Both lipid content and
composition did not vary significantly throughout the vertical aspect of the
blubber layer in adult male pilot whales. A repeated measures ANOVA
demonstrated no significant differences in the FA composition across blubber
layers indicating little differential deposition of FA components within the
inner, middle or outer portions of the blubber layer. The diet of Globicephala
melas was investigated by comparing signature fatty acid data of potential prey
to fatty acid profiles of both blubber and muscle tissue. Discriminant Function
Analysis for 18 prey species grouped into squid, fishes and crustaceans,
showed pilot whales grouping more closely with all fish (predominantly
myctophids) and three species of squid which feed on myctophids.
Item Details
Item Type: | Masters Research |
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Keywords: | fatty acid analysis, tissue lipid profiles, long-finned pilot whales, strandings, Tasmania |
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Environmental Management |
Objective Group: | Marine systems and management |
Objective Field: | Marine biodiversity |
UTAS Author: | Walters, A (Dr Andrea Walters) |
ID Code: | 128656 |
Year Published: | 2005 |
Deposited By: | Ecology and Biodiversity |
Deposited On: | 2018-10-05 |
Last Modified: | 2018-10-08 |
Downloads: | 4 View Download Statistics |
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