“… Figure 3 Principal Component Analysis (PCA) of fatty acid composition of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). Figure 4 Scatterplot of fatty acid ratios of vaccenic acid to oleic acid (18:1ω7c/18:1ω9c) and EPA to DHA of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). Figure 5 Scatterplot of the averages of eicosapentaenoic acid (20:5ω3) and docosahexaenoic acid (22:6ω3) of E1 humpback whales from 2008 to 2018 (n = 348).…”
Section: Resultsmentioning
confidence: 67%
“… Scatterplot of fatty acid ratios of vaccenic acid to oleic acid (18:1ω7c/18:1ω9c) and EPA to DHA of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). …”
Section: Resultsmentioning
confidence: 67%
“…Relationships between E1 humpback whales, their potential prey (data sources: Thysanoessa macrura : 17 – 19 ; E. superba : 20 – 23 ; Munida gregaria : 24 , 25 ; N. australis : 26 ; Emmelichthys nitidus , Sardinops neopilchardus , Trachurus declivis : 27 , 28 ) and northern hemisphere humpback whales (data source: 29 ) were evaluated by PCA using the 10 major fatty acids reported in all studies. The majority of fatty acid profiles of E1 humpback whales formed a distinct cluster, with some samples taken in 2008 representing outliers (Fig.…”
Southern hemisphere humpback whales are classified as high-fidelity Antarctic krill consumers and as such are vulnerable to variability and long-term changes in krill biomass. Evidence of heterogeneous feeding patterns of east coast of Australia migrating humpback whales has been observed, warranting a comprehensive assessment of interannual variability in their diet. We examined the lipid and fatty acid profiles of individuals of the east coast of Australia migrating stock sampled between 2008 and 2018. The use of live-sampled blubber biopsies showed that fatty acid profiles varied significantly among all years. The two trophic indicator fatty acids for Antarctic krill, 20:5ω3 and 22:6ω3 remained largely unchanged across the 10-year period, suggesting that Antarctic krill is the principal prey item. A distance-based linear model showed that 33% of the total variation in fatty acid profiles was explained by environmental variables and climate indices. Most of the variation was explained by the Southern Annular Mode (23.7%). The high degree of variability observed in this study was unexpected for a species that is thought to feed primarily on one prey item. We propose that the observed variability likely arises from changes in the diet of Antarctic krill rather than changes in the whale’s diet.
“… Figure 3 Principal Component Analysis (PCA) of fatty acid composition of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). Figure 4 Scatterplot of fatty acid ratios of vaccenic acid to oleic acid (18:1ω7c/18:1ω9c) and EPA to DHA of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). Figure 5 Scatterplot of the averages of eicosapentaenoic acid (20:5ω3) and docosahexaenoic acid (22:6ω3) of E1 humpback whales from 2008 to 2018 (n = 348).…”
Section: Resultsmentioning
confidence: 67%
“… Scatterplot of fatty acid ratios of vaccenic acid to oleic acid (18:1ω7c/18:1ω9c) and EPA to DHA of E1 humpback whales from 2008 to 2018 (this study), northern hemisphere humpback whales (data from Borobia et al 29 ), Antarctic krill (data from Phleger et al 23 ; Stübing and Hagen 22 ; Guang et al 17 ), temperate krill (data from Virtue et al 26 ) and other prey species ( T. macrura : Guang et al 17 ; Mayzaud et al 19 ; Kattner et al 77 ; M. gregaria : Phillips et al 25 ; Varisco et al 24 ; E. nitidus , S. neopilchardus , T. declivis : Nichols et al 28 ; Baylis et al 27 ). …”
Section: Resultsmentioning
confidence: 67%
“…Relationships between E1 humpback whales, their potential prey (data sources: Thysanoessa macrura : 17 – 19 ; E. superba : 20 – 23 ; Munida gregaria : 24 , 25 ; N. australis : 26 ; Emmelichthys nitidus , Sardinops neopilchardus , Trachurus declivis : 27 , 28 ) and northern hemisphere humpback whales (data source: 29 ) were evaluated by PCA using the 10 major fatty acids reported in all studies. The majority of fatty acid profiles of E1 humpback whales formed a distinct cluster, with some samples taken in 2008 representing outliers (Fig.…”
Southern hemisphere humpback whales are classified as high-fidelity Antarctic krill consumers and as such are vulnerable to variability and long-term changes in krill biomass. Evidence of heterogeneous feeding patterns of east coast of Australia migrating humpback whales has been observed, warranting a comprehensive assessment of interannual variability in their diet. We examined the lipid and fatty acid profiles of individuals of the east coast of Australia migrating stock sampled between 2008 and 2018. The use of live-sampled blubber biopsies showed that fatty acid profiles varied significantly among all years. The two trophic indicator fatty acids for Antarctic krill, 20:5ω3 and 22:6ω3 remained largely unchanged across the 10-year period, suggesting that Antarctic krill is the principal prey item. A distance-based linear model showed that 33% of the total variation in fatty acid profiles was explained by environmental variables and climate indices. Most of the variation was explained by the Southern Annular Mode (23.7%). The high degree of variability observed in this study was unexpected for a species that is thought to feed primarily on one prey item. We propose that the observed variability likely arises from changes in the diet of Antarctic krill rather than changes in the whale’s diet.
“…Romero et al (2006a) determined the ED of Munida subrugosa during its reproductive cycle but in ash-free dry mass terms. At a species level, values of 2.5 J g − 1 wet mass and 11.0 J g − 1 dry mass were determined for Euphausia lucens and M. gregaria in Patagonian waters, respectively (Ciancio et al 2007), while for the latter, ED values ranging from 3-4 kJ g − 1 were observed in the SJG (Varisco et al 2020). Worldwide, scarce literature on ED was found for the genus Munida, but some studies are available on euphausiids.…”
Section: Discussionmentioning
confidence: 99%
“…Prey ED is known to uctuate spatially and temporally (Ruck et al 2014;Chen et al 2019). Representative energy densities for many functional groups and whole geographic regions are still unavailable, and only a few studies have examined the ED in temperate waters (Romero et al 2006a;Ciancio et al 2007;Varisco et al 2020;Bruno et al 2023).…”
Macrozooplankton nutritional quality is essential information to understand the energy and matter fluxes in marine food webs and their value as prey for fish. Lipid-derived energy density (ED; kJ g− 1) and polyunsaturated fatty acids content (PUFA; µg mg− 1 total lipids) of Euphausia spp. and Munida gregaria were studied along a seasonal cycle (September 2016- November 2016-January 2017), and related with their size and the spatial environmental variability (satellite chlorophyll-a (chl-a) concentration and frontal structures) of the San Jorge Gulf (45°–47°S, 65°30′-67°30ʹW; Argentinean Continental Shelf, SW Atlantic Ocean). This gulf is a key nursery and feeding ground for many commercially and ecologically relevant fish species (e.g. Merluccius hubbsi). While ED was similar in both taxa, PUFA content was significantly higher in Euphausia spp. Quality indices showed seasonal and spatial variations, while the effect of size was non-significant. For both taxa, minimum ED values occurred in winter, while for Euphausia spp. the maximum was observed in summer and for M. gregaria in spring. M. gregaria ED tightly coupled with the seasonal chl-a cycle. PUFA content also varied seasonally, with an opposite trend. Spatially, higher ED and PUFA values occurred in locations with elevated chl-a concentrations. This was mostly manifested in M. gregaria indices and less evident in Euphausia spp. Results provide novel and baseline information of zooplankton, which can be applied in food web models to understand the trophic dynamics of many fish and top predators species in the Argentinean Shelf in the current global change context.
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