Lipid and fatty acid profiles of migrating Southern Hemisphere humpback whales Megaptera novaeangliae

Abstract

The lipid and fatty acid (FA) composition of the outer blubber layer was characterized in 46 east Australian migrating humpback whales Megaptera novaeangliae. Samples were obtained at 2 time points of the annual migration, which occurs between Antarctic feeding grounds and low-latitude breeding grounds and is associated with a prolonged period of fasting. Blubber lipid composition was dominated by triacylglycerols in all individuals, and the FA profiles of both migration cohorts and sexes were dominated by monounsaturated fatty acids (MUFA). Results indicate that males primarily mobilise polyunsaturated fatty acids in response to migration and fasting, favouring the most readily utilisable FA as governed by their physicochemical properties. In comparison, females appear to initially mobilise short-chain (<18 carbons) MUFA stores, potentially to attend to dependent calves' thermoregulatory needs. Feeding ecology investigations suggested that humpback whales have a species-specific FA composition of their blubber, including a detectable influence of their diet. This study provides the first insight into lipid and FA profiles of Southern Hemisphere humpback whales. A comprehensive understanding of FA dynamics, especially during times of energy deficit, is essential for understanding the nutritional status of Southern Hemisphere humpback whales and thereby the risks posed by growing environmental threats including toxic and persistent lipophilic pollutants. KEY WORDS: Humpback whale · Megaptera novaeangliae · Biopsy sampling · Blubber · Fatty acid Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 471: [271][272][273][274][275][276][277][278][279][280][281] 2012 files can provide further information regarding thermoregulatory and insulating properties of the tissue as well as complement toxicokinetic investigations of lipophilic pollutants, the movement of which are governed by lipid dynamics (Strandberg et al. 2008(Strandberg et al. , 2011. Most recently, FA regression models have been employed as a novel non-lethal method of age estimation in certain populations of large biopsied cetaceans (Herman et al. 2008(Herman et al. , 2009.Marine mammal blubber is dynamic in nature and significantly influenced by nutritional condition (Budge et al. 2006). In times of low food availability, animals mobilise stored blubber FA to provide metabolic fuel. Conversely, animals deposit FA when energy intake exceeds demands. FA metabolism at times of energy deficit is not well understood in marine mammals, especially in large baleen whales, although there is evidence to suggest that in some species it is a selective and/or temporal process (Raclot 2003, Wheatley et al. 2008). To better understand the lipid dynamics of Southern Hemisphere humpback whales Megaptera novaeangliae, we focused this study on the east Australian migrating population (E1, as designated by the International Whaling Commission, 1999).Southern Hemisphere humpback whales have adapted to the productivity e...

Diet of whale sharks Rhincodon typus inferred from stomach content and signature fatty acid analyses

“…In addition to the unusually high levels of ω6 PUFA in whale sharks first reported in Couturier et al (2013b), we show here that the full FA profile of Ackman et al 1971, Hooper et al 1973, Holland et al 1990, Pethybridge et al 2010, Waugh et al 2012, Couturier 2013b. The 2 data points for the leatherback turtle represent the neutral-and phospholipid fractions for the pectoral muscle of a single animal.…”

“…Comparative signatures from the reef manta ray Manta alfredi (n = 13; Couturier 2013b), leatherback turtle Dermochelys coriacea (n = 1, neutral-and phospholipids; Holland et al 1990), ocean sunfish Mola mola (n = 2; Hooper et al 1973), fin whale Balaenoptera physalus, harp seal Pagophilus groenlandica (means; Ackman et al 1971), humpback whale Megaptera novaengliae (means of n = 2 to 17; Waugh et al 2012), and 15 species of deep-sea chondrichthyans (means of n = 1 to 10; Pethybridge et al 2010) were obtained as context for the results from whale sharks.…”

“…This is likely to be due to their reliance on gelatinous zooplankton, especially jellyfish (Hough ton et al 2006), which also contain relatively high levels of ARA, EPA and DHA (Holland et al 1990, Nichols et al 2003, van der Bank et al 2011. A suite of deepsea chondrichthyans (Pethybridge et al 2010) and the sunfish (Hooper et al 1973) had higher levels of DHA than whale sharks, and marine mammals (Ackman et al 1971, Waugh et al 2012) contained more 16:1ω7, 18:1ω9 and EPA than whale sharks. Comparing FA profiles of whale sharks with those of their observed or hypothesised prey further highlighted the unusual nature of the FA profile of whale sharks.…”

Opposing Lethal Wildlife Research When Nonlethal Methods Exist: Scientific Whaling as a Case Study

“…Whale blow is increasingly being utilized for novel measures such as biogenic volatile organic compound profiling, which can be used to assess the health and physiological processes within an animal (Cumeras et al 2014). Nonlethal whale blubber biopsies can be used for a large variety of studies and parameters including endocrinology (Vu et al 2015), lipid and fatty acid and diet profiling (Waugh et al 2012), as well as toxicological surveys ) and effects (Bengtson Nash et al 2013). Whale skin samples can be used for studies such as enzyme activity and health biomarkers (Waugh et al 2011;Bengtson Nash et al 2014) and for epigenetic age estimation (Polanowski et al 2014).…”

Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): Implications for biochemical biomarker assessment

“…Some studies have found a weak correlation between blubber thickness and nutritional conditions (Caon et al, 2007;Evans et al, 2003;Gómez-Campos et al, 2011;Read, 1990), which can be attributed to the fact that lipid content of blubber can vary independently of blubber thickness (Ackman et al, 1975a). Blubber plays an important role in energy storage, however also plays a role in other important physiological functions which, may present a threshold on the amount of lipid that can be lost from the tissue without jeopardizing its ancillary physiological functions (Gómez-Campos et al, 2011;Noren et al, 2015;Waugh et al, 2012). On the other hand, measurements of blubber thickens does not take account of visceral fat deposits, that seems to act as a secondary energy storage in the body cavity (Lockyer et al, 1985), it is suggested, that these deposits might be more mobile than those in blubber (Niaess et al, 1998), being the last in and the first out in the lipid dynamics.…”