The diet of the Weddell seal Leptonychotes weddellii at Laurie Island, South Orkney Islands

Casaux, Ricardo; Carlini, Alejandro R; Corbalán, A.; Bertolin, L.; Prinzio, Cecilia Yanina Di

doi:10.1007/s00300-009-0583-8

Cited by 16 publications

(9 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Yet the body contains only minuscule amounts of carbohydrate in the form of blood sugar and tissue glycogen, typically less than 0.5% of body mass (Kemp and Van Heijningen 1954;Kerem et al 1973;Flatt 1995). Weddell seals consume a diet of marine fish and invertebrates (Dearborn 1965;Casaux et al 1997Casaux et al , 2006Casaux et al , 2009Lake et al 2003) that is expected to contain very low levels of available carbohydrate (≤0.5% by mass) in the form of glycogen (MacPherson 1932;Oehlenschläger 1991;Rosa et al 2005). Like other specialized mammalian carnivores that subsist exclusively on animal prey ("hypercarnivores"), adult seals have to meet their metabolic glucose demand by synthesizing glucose from amino acids and glycerol (Eisert 2011).…”

Section: Milk Carbohydrate and Its Functional Significancementioning

confidence: 99%

Milk Composition in the Weddell SealLeptonychotes weddellii: Evidence for a Functional Role of Milk Carbohydrates in Pinnipeds

Eisert¹,

Oftedal²,

Barrell³

2013

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

We propose that secretion of milk sugar has important consequences for the metabolic economies of lactating phocid seals and their pups. Milk was collected from 21 Weddell seals Leptonychotes weddellii in McMurdo Sound, Antarctica, and assayed by standard methods. Milk composition changed over the course of lactation, but at mid- to late lactation (16-40 d postpartum), Weddell seal milk composition was relatively constant at 33.8% +/- 0.82% water, 54.0% +/- 0.80% fat, 10.1% +/- 0.16% crude protein, 0.84% +/- 0.03% sugar, 0.75% +/- 0.02% ash, and 23.3 +/- 0.3 kJ g−1 whole milk (WM). At this stage, milk composition varied among individual seals in all assayed constituents except ash. The concentration of sugar in the aqueous phase of Weddell seal milk ( 24.9 +/- 0.6g sugar L−1 water) was ca. 44%-77% of levels found in terrestrial carnivores, indicating that the low sugar concentration of WM is primarily due to its high fat content, not alteration of the aqueous phase. In early lactation, fasting Weddell seals were estimated to devote 39 g d(-1) glucose to milk sugar synthesis, an amount similar to the estimated demand of the maternal brain. This additional glucose demand must be covered by gluconeogenesis in fasting animals and represents a considerable additional drain on maternal resources. However, provision of sugar to offspring at rates sufficient to meet neonatal substrate requirements appears to be essential for efficient fat and protein deposition and thus may be an important component of the phocid reproductive strategy of rapid growth and early weaning.

show abstract

Section: Milk Carbohydrate and Its Functional Significancementioning

confidence: 99%

Milk Composition in the Weddell SealLeptonychotes weddellii: Evidence for a Functional Role of Milk Carbohydrates in Pinnipeds

Eisert¹,

Oftedal²,

Barrell³

2013

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

show abstract

“…The octopods, Pareledone charcoti, P. turqueti and Megaleledone setebos (=M. senoi), were previously reported in the diet of Weddell seals in the Scotia Arc and Antarctic Peninsula, with P. charcoti and P. turqueti as the main prey species (Lipinski and Woyciechowski 1981;Clarke and MacLeod 1982;Cassaux et al 1997;Casaux et al 2006Casaux et al , 2009Daneri et al 2012). The genus Pareledone also occurred in the diet of Weddell seals in East Antarctica (Lake et al 2003).…”

Section: Discussionmentioning

confidence: 93%

“…Bertram 1940;Dearborn 1965;Davis et al 1982;Testa et al 1985;Plötz 1986;Casaux et al 2006Casaux et al , 2009. Despite the low number of scats collected from only 1 month a long time ago at Cape Shirreff, the order Octopoda accounted for 100 % of the cephalopod component.…”

Section: Discussionmentioning

confidence: 96%

“…At Nelson Island, octopods were again the main component of the cephalopod diet of Weddell seals (Cassaux et al 1997). Casaux et al (2009) also analysed the diet of Weddell seals during two periods at Laurie Island in the South Orkney Islands, and although octopods were present in more than 60 % of the scats collected, their contribution in terms of numbers and mass differed between the collection periods. In all three previous studies conducted in the Scotia Arc and in the present study, squid in the diet was negligible or absent.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Cephalopod remains in scats of Weddell seals (Leptonychotes weddellii) at Cape Shirreff, South Shetland Islands, Antarctica

et al. 2015

View full text Add to dashboard Cite

The diet of Weddell seals (Leptonychotes weddellii) varies regionally, and fish and cephalopods are thought to be the most important food source. However, there is limited information on the cephalopod component of the Weddell seal's diet in the South Shetland Islands. We investigated cephalopod remains in the diet of Weddell seals by analysing 21 scats collected on three beaches at Cape Shirreff, Livingston Island, Antarctica, from 1 to 20 February 1999. Although the number of scats is small and collected from only 1 month a long time ago, fish and cephalopods were present in 21 and 16 of the scats, respectively. Only cephalopods of the order Octopoda were represented. Thaumeledone sp. was the most abundant prey species in terms of numbers, followed by Pareledone charcoti and P. turqueti. The latter two species showed the highest frequency of occurrence in scats (10 and 9, respectively). Graneledone macrotyla, Opistoteuthis sp., Argonauta sp., Haliphron sp. and Thaumeledone sp. are new species identified in the diet of Weddell seals in the present study, but all made a negligible contribution to their diet at Cape Shirreff. Our findings agree with previous dietary studies of Weddell seals at other localities in the South Shetland Islands and the Antarctic Peninsula, which showed a relatively greater contribution of octopods to the diet compared with squid in summer.

show abstract

“…Many of the diet studies referenced within the diet matrix have small, spatially constrained sample sizes relative to their respective populations (e.g. [49, 50, 51]). It was assumed that the diets presented in studies covering small or restricted areas accurately represent the diversity of important prey items for each species, but that the percentage of mass in the diet was uncertain.…”

Section: Methodsmentioning

confidence: 99%

Using sea-ice to calibrate a dynamic trophic model for the Western Antarctic Peninsula

2019

View full text Add to dashboard Cite

The pelagic ecosystems of the Western Antarctic Peninsula are dynamic and changing rapidly in the face of sustained warming. There is already evidence that warming may be impacting the food web. Antarctic krill, Euphausia superba , is an ice-associated species that is both an important prey item and the target of the only commercial fishery operating in the region. The goal of this study is to develop a dynamic trophic model for the region that includes the impact of the sea-ice regime on krill and krill predators. Such a model may be helpful to fisheries managers as they develop new management strategies in the face of continued sea-ice loss. A mass balanced food-web model (Ecopath) and time dynamic simulations (Ecosim) were created. The Ecopath model includes eight currently monitored species as single species to facilitate its future development into a model that could be used for marine protected area planning in the region. The Ecosim model is calibrated for the years 1996–2012. The successful calibration represents an improvement over existing Ecopath models for the region. Simulations indicate that the role of sea ice is both central and complex. The simulations are only able to recreate observed biomass trends for the monitored species when metrics describing the sea-ice regime are used to force key predator-prey interactions, and to drive the biomasses of Antarctic krill and the fish species Gobionotothen gibberifrons . This model is ready to be used for exploring results from sea-ice scenarios or to be developed into a spatial model that informs discussions regarding the design of marine protected areas in the region.

show abstract

The diet of the Weddell seal Leptonychotes weddellii at Laurie Island, South Orkney Islands

Cited by 16 publications

References 26 publications

Milk Composition in the Weddell SealLeptonychotes weddellii: Evidence for a Functional Role of Milk Carbohydrates in Pinnipeds

Milk Composition in the Weddell SealLeptonychotes weddellii: Evidence for a Functional Role of Milk Carbohydrates in Pinnipeds

Cephalopod remains in scats of Weddell seals (Leptonychotes weddellii) at Cape Shirreff, South Shetland Islands, Antarctica

Using sea-ice to calibrate a dynamic trophic model for the Western Antarctic Peninsula

Contact Info

Product

Resources

About