Abstract
Weddell seals, Leptonychotes weddellii, are important apex predators in the food web of the Antarctic marine ecosystem. However, detailed information on their trophic relationships with cephalopods is scarce. Moreover, cephalopods play a key role in the marine environment, but knowledge of their feeding habits is limited by lack of data. Here, we have combined the use of this seal as a biological sampler together with measurements of the stable isotopic signature of the beaks of their cephalopod prey. Thus, the aims of the present study were: (1) to examine in detail the cephalopod portion of the diet of Weddell seals by means of scat analysis and (2) to assess the habitat use and trophic level of the different cephalopod prey taxa identified. From January to February 2009, a total of 48 faecal droppings were collected at Hope Bay, Antarctic Peninsula. Cephalopods were mainly represented by beaks (n = 83) which were identified to the lowest possible taxonomic level. Furthermore, subsamples of beaks were separated for further isotopic analysis. Relative abundance of stable isotopes of carbon (δ13C) and nitrogen (δ15N) was determined by continuous-flow isotope-ratio mass spectrometry. Cephalopods were represented uniquely by octopods of the subfamily Eledoninae. Pareledone turqueti was the dominant prey species followed by the papillated Pareledone species group and Adelieledone polymorpha. We conclude that Weddell seals preyed primarily on benthic prey resources. Furthermore, the relatively similar δ13C and δ15N values in beaks of the three octopod prey taxa suggest that these share the same type of habitat and occupy similar trophic level positions.
This is a preview of subscription content, log in via an institution to check access.
References
Allcock AL (2005) On the confusion surrounding Pareledone charcoti (Joubin 1905) (Cephalopoda: Octopodidae): endemic radiation in the Southern Ocean. Zool J Linn Soc 143:75–108
Allcock AL, Strugnell JM, Prodöhl P, Piatkowski U, Vecchione M (2007) A new species of Pareledone (Cephalopoda: Octopodidae) from Antarctic Peninsula waters. Polar Biol 30:883–893
Atkinson A, Siegel V, Pakhomov E, Rothery P (2004) Long-term decline in krill stock and increase in salps within the Southern Ocean. Nature 432:100–103
Burns J, Trumble S, Castellini M, Testa J (1998) The diet of the Weddell seals in McMurdo sound, Antarctica, as determined from scat collections and stable isotope analysis. Polar Biol 19:272–282
Casaux R, Baroni A, Carlini A (1997) The diet of the Weddell seal Leptonychotes weddellii at harmony point, South Shetland Islands. Polar Biol 18:371–375
Casaux R, Carlini A, Corbalán A, Bertolin L, DiPrinzio CY (2009) The diet of the Weddell seal Leptonychotes weddellii at Laurie Island, South Orkney Islands. Polar Biol 32:833–838
Castellini M, Davis R, Kooymann G (1992) Diving behavior and ecology of the Weddell seal: annual cycles. Bull of the Scripps Ins Oceanogr U Calif Press 28:1–54
Cherel Y, Hobson K (2005) Stable isotopes, beaks and predators: a new tool to study the trophic ecology of cephalopods, including giant and colossal squids. Proc R Soc Lond B 272:1601–1607
Cherel Y, Duhamel G, Gasco N (2004) Cephalopod fauna of subantarctic islands: new information from predators. Mar Ecol Prog Ser 266:143–156
Cherel Y, Koubbi P, Giraldo C, Penot F, Tavernier E, Moteki M, Ozouf-Costaz C, Causse R, Chartier A, Hosie G (2011) Isotopic niches of fishes in coastal, neritic and oceanic waters off Adélie Land, Antarctica. Polar Sci 5:286–297
Clarke MR (1986) A handbook for the identification of cephalopod beaks. Clarendon Press, Oxford
Clarke M, MacLeod N (1982) Cephalopod remains in the stomachs of eight Weddell Seals. Br Antarc Surv Bull 57:33–40
Collins MA, Rodhouse PGK (2006) Southern ocean cephalopods. Adv Mar Biol 50:191–265
Daneri GA, Piatkowski U, Coria NR, Carlini AR (1999) Predation on cephalopods by Antarctic fur seals, Arctocephalus gazella, at two localities of the Scotia Arc, Antarctica. Polar Biol 21:59–63
Daneri GA, Carlini AR, Rodhouse PGK (2000) Cephalopod diet of the southern elephant seal, Mirounga leonina, at King George Island, South Shetland Islands. Antarct Sci 12:16–19
Daneri GA, Carlini AR, Negri A, Allcock L, Corbalán A (2012) Predation on cephalopods by Weddell seals, Leptonychotes weddellii, at Hope Bay, Antarctic Peninsula. Polar Biol 35:585–592
Dearborn J (1965) Food of Weddell seals at Mc Murdo sound, Antarctica. J Mammal 46:37–43
Forcada J, Trathan PN (2009) Penguin responses to climate change in the Southern Ocean. Glob Change Biol 15:1618–1630
Green K, Burton H (1987) Seasonal and geographical variation in the food of Weddell seals Leptonychotes weddellii in Antarctica. Aust Wildl Res 14:475–489
Gröger J, Piatkowski U, Heinemann H (2000) Beak length analysis of the Southern Ocean squid Psychroteuthis glacialis (Cephalopoda: Psychroteuthidae) and its use for size and biomass estimation. Polar Biol 23:70–74
Imber MJ (1992) Cephalopods eaten by wandering albatrosses (Diomedea exulans L.) breeding at six circum-polar localities. J R Soc N Z 22:243–263
Lake S, Burton H, Van den Hoff J (2003) Regional, temporal and fine-scale spatial variation in Weddell seal diet at four coastal locations in east Antarctica. Mar Ecol Prog Ser 254:293–305
Lipinski M, Woyciechowski M (1981) Cephalopods in the food of Weddell seals from the Admiralty Bay (King George Island, South Shetland Islands). Pol Polar Res 2:163–167
Lu CC, Ickeringill R (2002) Cephalopod beak identification and biomass estimation techniques: tools for dietary studies of southern Australian finfishes. Vic Mus Sci Rep 6:1–65
Plötz J (1986) Summer diet of Weddell seals (Leptonychotes weddellii) in the eastern and southern Weddell Sea, Antarctica. Polar Biol 6:97–102
Plötz J, Ekau W, Reijnders PJH (1991) Diet of Weddell seals Leptonychotes weddellii at Vestkapp, eastern Weddell Sea (Antarctica), in relation to local food supply. Mar Mamm Sci 7:136–144
Proffitt K, GarrottR Rotella J, Wheatley K (2007) Environmental and senescent related variations in Weddell seal body mass: implications for age-specific reproductive performance. Oikos 116:1683–1690
Reeves RR, Stewart BS, Leatherwood S (1992) The Sierra Club handbook of seal and sirenians. Sierra Club Books, San Francisco
Rodhouse PGK (1990) Cephalopod fauna of the Scotia Sea at South Georgia: potential for commercial exploitation and possible consequences. In: Kerry K, Hempel G (eds) Ecological change and the conservation of antarctic ecosystems. Proceedings of the 5th SCAR symposium on antarctic biology. Springer, Berlin, pp 289–298
Testa JW (1994) Over-winter movements and diving behavior of females Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica. Can J Zool 72:1700–1710
Xavier JC, Cherel Y (2009) Cephalopod beak guide for the Southern Ocean. Brit Antarct Surv B, Cambridge
Xavier JC, Louzao M, Thorpe SE, Ward P, Hill C, Roberts D, Croxall JP, Phillips RA (2013) Seasonal changes in the diet and feeding behaviour of a top predator indicates a flexible response to deteriorating oceanographic conditions. Mar Biol 160:1597–1606
Zhao L, Castellini MA, Mau TL, Trumble SJ (2004) Trophic interactions of Antarctic seals as determined by stable isotope signatures. Polar Biol 27:368–373
Acknowledgments
This work received financial support from the Dirección Nacional del Antártico and the Agencia Nacional de Promoción Científica y Tecnológica (Grant: PICTO No. 36054). It was also partly funded by the Foundation for Science and Technology (Portugal) and within the Portuguese Polar Program PROPOLAR.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Negri, A., Daneri, G.A., Ceia, F. et al. The cephalopod prey of the Weddell seal, Leptonychotes weddellii, a biological sampler of the Antarctic marine ecosystem. Polar Biol 39, 561–564 (2016). https://doi.org/10.1007/s00300-015-1794-9
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00300-015-1794-9