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Marine Biology

, Volume 150, Issue 6, pp 1441–1452 | Cite as

Age-related shifts in the diet composition of southern elephant seals expand overall foraging niche

  • Iain C. FieldEmail author
  • Corey J. A. Bradshaw
  • John van den Hoff
  • Harry R. Burton
  • Mark A. Hindell
Research Article

Abstract

Southern elephant seals are important apex predators in a highly variable and unpredictable marine environment. In the presence of resource limitation, foraging behaviours evolve to reduce intra-specific competition increasing a species’ overall probability of successful foraging. We examined the diet of 141 (aged 1–3 years) juvenile southern elephant seals to test the hypotheses that differences between ages, sexes and seasons in diet structure occur. We described prey species composition for common squid and fish species and the mean size of cephalopod prey items for these age groups. Three cephalopod species dominated the stomach samples, Alluroteuthis antarcticus, Histioteuthis eltaninae and Slosarczykovia circumantarcticus. We found age-related differences in both species composition and size of larger prey species that probably relate to ontogenetic changes in diving ability and haul-out behaviour and prey availability. These changes in foraging behaviour and diet are hypothesised to reduce intra-specific food competition concomitant with the increase in foraging niche of growing juveniles.

Keywords

Southern Ocean Prey Species Diet Composition Elephant Seal Southern Elephant Seal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

The data were collected with the approval of the Australian Antarctic Animal Ethics Committee and permits from the Tasmanian Parks and Wildlife Service . We thank M. Biuw, J. Harrington, C. McKinley, N. Milius, R. Munro, M. Pauza and K. Wheatley and members of the 51st–53rd ANARE to Macquarie Island for their assistance during fieldwork. We thank D. Williams for the identification of the otoliths collection and Y. Cherel and M. Imber for reviewing our identifications of squid beaks. We thank M. Sumner for helping with R programming. Funding was provided by the Antarctic Science Advisory Committee and Sea World Research and Rescue Foundation Inc.

References

  1. Adams RA (1996) Size-specific resource use in juvenile little brown bats, Myotis lucifugus (Chiroptera: Vespertilionidae): is there an ontogenetic shift? Can J Zool 74:1204–1210CrossRefGoogle Scholar
  2. Antonelis GA, Lowry MS, Fiscus CH, Stewart BS, DeLong RL (1994) Diet of the northern elephant seal. In: Le Boeuf BJ, Laws RM (eds) Elephant seals: population ecology, behaviour, and physiology. University of California Press, Berkeley, pp 211–226Google Scholar
  3. Arkhipkin AI, Bjørke H (1999) Ontogenetic changes in morphometric and reproductive indices of the squid Gonatus fabricii (Oegopsida Gonatidae) in the Norwegian Sea. Polar Biol 22:357–365CrossRefGoogle Scholar
  4. Arnett RTP, Whelan J (2001) Comparing the diet of cod (Gadus morhua) and grey seals (Halichoerus grypus): an investigation of secondary ingestion. J Mar Biol Assoc UK 81:365–366CrossRefGoogle Scholar
  5. Arrigo KR, Worthen D, Schnell A, Lizotte MP (1998) Primary production in Southern Ocean waters. J Geophys Res 103(C8):15587–15600CrossRefGoogle Scholar
  6. Bolnick DI, Svanbäck R, Fordyce JA, Yang LH, Davis JM, Hulsey CD, Forister ML (2003) The ecology of individuals: incidence and implications of individual specialization. Am Nat 161:1–28CrossRefGoogle Scholar
  7. Bowen WD, Tully D, Boness DJ, Bulheier BM, Marshall GJ (2002) Prey dependent foraging tactics and prey profitability in a marine mammal. MEPS 244:235–245CrossRefGoogle Scholar
  8. Boyd IL, Arnbom TA, Fedak MA (1994) Biomass and energy consumption of the South Georgia population of the southern elephant seals. In: Le Boeuf BJ, Laws RM (eds) Elephant seals: population ecology, behaviour, and physiology. University of California Press, Berkeley, pp 98–120Google Scholar
  9. Bradshaw CJA, Hindell MA, Best NJ, Phillips KL, Wilson G, Nichols PD (2003) You are what you eat: describing the foraging ecology of southern elephant seals (Mirounga leonina) using blubber fatty acids. Proc R Soc Lond B 270:1283–1292CrossRefGoogle Scholar
  10. Brown DJ, Boyd IL, Cripps GC (1999) Fatty acid signature analysis from the milk of Antarctic fur seals and southern elephant seals from South Georgia: implications for diet determination. Mar Ecol Prog Ser 187:251–263CrossRefGoogle Scholar
  11. Burton HR, van den Hoff J (2002) Humans and the southern elephant seal Mirounga leonina. Aust Mamm 24:127–139CrossRefGoogle Scholar
  12. Cherel Y, Duhamel G, Gasco N (2004) Cephalopod fauna of subantarctic islands: new information from predators. Mar Ecol Prog Ser 266:143–156CrossRefGoogle Scholar
  13. Clarke MR (1986) A handbook for the identification of cephalopod beaks. Clarendon, OxfordGoogle Scholar
  14. Clinton WL (1994) Sexual selection and growth in male northern elephant seals. In: Le Boeuf BJ, Laws RM (eds) Elephant seals: population ecology, behaviour, and physiology. University of California Press, Berkeley, pp 154–168Google Scholar
  15. Constable AJ, Nicol S, Strutton PG (2003) Southern Ocean productivity in relation to spatial and temporal variation in the physical environment. J Geophys Res 108:8079–9000CrossRefGoogle Scholar
  16. Daneri GA, Carlini AR (2002) Fish prey of southern elephant seals, Mirounga leonina, at King George Island. Polar Biol 25(10):739–743Google Scholar
  17. Danieri GA, Carlini AR, Rodhouse PGK (2000) Cephalopod diet of the southern elephant seal, Mirounga leonina, at King George Island, South Shetland Islands. Antarct Sci 12:16–19Google Scholar
  18. El-Sayed SZ (1988) Seasonal and inter-annual variabilities in Antarctic phytoplankton with reference to krill distribution. In: Sahrhage D (ed) Antarctic ocean and resource variability. Springer, Berlin Heidelberg New York, pp 101–119CrossRefGoogle Scholar
  19. Field IC, Bradshaw CJA, McMahon CR, Harrington J, Burton HR (2002) Intravenous anaesthesia of elephant seals (Mirounga leonina) using tiletamine and zolazepam: effects of age, size, condition and function of haul-out. Vet Rec 151:235–240CrossRefGoogle Scholar
  20. Field IC, Bradshaw CJA, Burton HR, Hindell MA (2004) Seasonal use of oceanographic and fisheries management zones by juvenile southern elephant seals (Mirounga leonina) from Macquarie Island. Polar Biol 27:432–440CrossRefGoogle Scholar
  21. Field IC, Bradshaw CJA, Burton HR, Sumner MD, Hindell MA (2005a) Resource partitioning through oceanic segregation of foraging juvenile southern elephant seals. Oecologia 142:127–135CrossRefGoogle Scholar
  22. Field IC, Bradshaw CJA, Burton HR, Hindell MA (2005b) Patterns of onshore mass change and metabolism in juvenile southern elephant seals. Physiol Biochem Zool 78(4):491–504CrossRefGoogle Scholar
  23. Green K, Slip DJ, Moore GJ (1998) The take of fish species by seabirds and marine mammals in the Australian Fisheries Zone around Heard Island—the potential for competition with a commercial fishery. Polar Biol 20:273–280CrossRefGoogle Scholar
  24. Guinet C, Jouventin P, Weimerskirch H (1999) Recent population change of the southern elephant seal at Iles Crozet and Iles Kerguelen: the end of the decrease? Antarct Sci 11(2):193–197CrossRefGoogle Scholar
  25. Hindell MA, Slip DJ, Burton HR (1994) Possible causes of the decline of southern elephant seal populations in the southern Pacific and southern Indian Oceans. In: Le Boeuf BJ, Laws RM (eds) Elephant seals: population ecology, behavior, and physiology. University of California Press, Berkeley, pp 66–84Google Scholar
  26. Hindell MA, McConnell BJ, Fedak MA, Slip DJ, Burton HR, Reijnders PJH, McMahon CR (1999) Environmental and physiological determinants of successful foraging by naive southern elephant seal pups during their first trip to sea. Can J Zool 77:1807–1821CrossRefGoogle Scholar
  27. Hindell MA, Bradshaw CJA, Sumner MD, Michael KJ, Burton HR (2003) Dispersal of female southern elephant seals and their prey consumption during the austral summer: relevance to management and oceanographic zones. J Appl Ecol 40:703–715CrossRefGoogle Scholar
  28. van den Hoff J (2004) A comparative study of the cephalopod prey of Patagonian toothfish (Dissostichus eleginoides) and southern elephant seals (Mirounga leonina) near Macquarie Island. Polar Biol 27:604–612CrossRefGoogle Scholar
  29. van den Hoff J, Burton HR, Davies R (2003) Diet of male southern elephant seals (Mirounga leonina) hauled out at Vincennes Bay, East Antarctica. Polar Biol 26:27–31Google Scholar
  30. Hooker SK, Iverson SJ, Ostrom P, Smith SC (2001) Diet of northern bottlenose whales inferred from fatty-acid and stable isotope analysis of biopsy samples. Can J Zool 75:188–197Google Scholar
  31. Ihaka R, Gentleman R (1996) R: a language for data analysis and graphics. J Comput Graph Stat 5:299–314Google Scholar
  32. Irvine LG, Hindell MA, van den Hoff J, Burton HR (2000) The influence of body size on dive duration of under-yearling southern elephant seals (Mirounga leonina). J Zool 251:463–471CrossRefGoogle Scholar
  33. Iverson SJ, Field C, Bowen WD, Blanchard W (2004) Quantitative fatty acid signature analysis: a new method of estimating predator diets. Ecol Monogr 74:211–235CrossRefGoogle Scholar
  34. Jackson GD (1993) Growth zone within the statolith microstructure of the deepwater squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae): evidence for a habitat shift? Can J Fish Aquat Sci 50:2366–2374CrossRefGoogle Scholar
  35. Jackson AC, Rundle SD, Attrill MJ, Cotton PA (2004) Ontogenetic changes in metabolism may determine shifts for a sit and wait predator. J Anim Ecol 73:536–545CrossRefGoogle Scholar
  36. Jarman SN, Gales NJ, Tierney M, Gill PC, Elliot NG (2002) A DNA-based method for identification of krill species and its application to analysing the diet of marine vertebrate predators. Mol Ecol 11:2679–2690CrossRefGoogle Scholar
  37. Kato A, Watanuki Y, Nishiumi I, Kuroki M, Shaughnessy P, Naito Y (2000) Variation in foraging and parental behaviour of king cormorants. Auk 117:718–730CrossRefGoogle Scholar
  38. Krockenberger MB, Bryden MM (1994) Rate of passage of digesta through the alimentary tract of southern elephant seals (Mirounga leonina) (Carnivora: Phicidae). J Zool (Lond) 234:229–237CrossRefGoogle Scholar
  39. Le Boeuf BJ, Laws RM (1994) Elephant seals: an introduction to the genus. In: Le Boeuf BJ, Laws RM (eds) Elephant seals: population ecology, behavior, and physiology. University of California Press, Berkeley, pp 1–28Google Scholar
  40. Le Boeuf BJ, Morris PA, Blackwell SB, Crocker DE, Costa DP (1996) Diving behaviour of juvenile northern elephant seals. Can J Zool 74:1632–1644CrossRefGoogle Scholar
  41. Le Boeuf BJ, Crocker DE, Costa DP, Blackwell SB, Webb PM, Houser DS (2000) Foraging ecology of northern elephant seals. Ecol Monogr 70:353–382CrossRefGoogle Scholar
  42. Lipinski MR (2001) Preliminary description of two new species of Cephalopods (Cephalopoda: Brachioteuthidae) from the South Atlantic and Antarctic waters. Bull Sea Fish Inst 1:3–14Google Scholar
  43. Lutjeharms JHE (1990) The oceanography and fish distribution of the Southern Ocean. In: Gon O, Heemstra PC (eds) Fishes of the Southern Ocean. Institute of Ichthyology, Grahamstown, pp 6–28Google Scholar
  44. McMahon CR, Burton H, McLean S, Slip D, Bester M (2000) Field immobilisation of southern elephant seals with intravenous tiletamine and zolazepam. Vet Rec 146:251–254CrossRefGoogle Scholar
  45. McMahon CR, Burton HR, Bester MN (2003) A demographic comparison of two southern elephant seals populations. J Anim Ecol 72:61–74CrossRefGoogle Scholar
  46. McMahon CR, Bester MN, Burton HR, Hindell MA, Bradshaw CJA (2005) Population status and trends of a wide-ranging marine mammal predator, the southern elephant seal: re-examining hypotheses to explain the decline. Mammal Rev 35:82–100CrossRefGoogle Scholar
  47. Perry G (1996) The evolution of sexual dimorphism in the lizard Anolis polylepis (Iguania): evidence from intraspecific variation in foraging behaviour and diet. Can J Zool 74:1238–1245CrossRefGoogle Scholar
  48. Phillips KL, Nichols PD, Jackson GD (2003) Size-related dietary changes observed in the squid Moroteuthis ingens at the Falkland Islands: stomach contents and fatty-acid analyses. Polar Biol 26:474–485Google Scholar
  49. Pianka ER (1981) Competition and niche theory. In: May RM (ed) Theoretical ecology: principles and applications. Blackwell Scientific Publications, Oxford, pp 114–141Google Scholar
  50. Piatkowski U, Vergani DF, Stanganelli ZB (2002) Changes in cephalopod diet of the southern elephant seal females a King George Island, during El Niño-La Niña events. J Mar Biol Assoc UK 82:913–916CrossRefGoogle Scholar
  51. Polis A (1984) Age structure component of niche width and intraspecific resource partitioning: can age groups function as ecological species? Am Nat 123:541–564CrossRefGoogle Scholar
  52. Radloff FGT, Du Toit JT (2004) Large predators and their prey in a southern African savanna: a predator’s size determines its prey size. J Anim Ecol 73:410–423CrossRefGoogle Scholar
  53. Rodhouse PG, White MG (1995) Cephalopods occupy the ecological niche of epipelagic fish in the Antarctic Polar Frontal zone. Biol Bull 189:77–80CrossRefGoogle Scholar
  54. Rodhouse PG, Arnbom TR, Fedak MA, Yeatman J, Murray AWA (1992) Cephalopod prey of the southern elephant seal Mirounga leonina L. Can J Zool 70:1007–1015CrossRefGoogle Scholar
  55. Roper CFE, Sweeney MJ, Nauen CE (1984) Cephalopods of the world, vol 3. Food and Agriculture Organization, Rome, Italy, pp 277Google Scholar
  56. Santos MB, Clarke MR, Pierce GJ (2001) Assessing the importance of cephalopods in the diets of marine mammals and other top predators: problems and solutions. Fish Res 52:121–139CrossRefGoogle Scholar
  57. Schoener TW (1986) Resource partitioning. In: Kikkawa J, Anderson DJ (eds) Community ecology pattern and process. Blackwell Scientific Publications, Carlton, pp 91–126Google Scholar
  58. Slip DJ (1995) The diet of southern elephant seals (Mirounga leonina) from Heard Island. Can J Zool 63:1519–1528CrossRefGoogle Scholar
  59. Slip DJ (1997) Diving and foraging behaviour of juvenile southern elephant seals from Heard Island. In: Hindell M, Kemper C (eds) Marine mammal research in the Southern Hemisphere: status, ecology and medicine, vol 1. Beatty and Sons, Chipping Norton, pp 114–124Google Scholar
  60. Slip DJ, Burton HR (1999) Population status and seasonal haulout patterns of the southern elephant seal (Mirounga leonina) at Heard Island. Antarct Sci 11(1):38–47CrossRefGoogle Scholar
  61. Spina AP (2000) Habitat partitioning in patchy environment: considering the role of intraspecific competition. Environ Biol Fish 57:393–400CrossRefGoogle Scholar
  62. Stewart BS (1997) Ontogeny of differential migration and sexual segregation in northern elephant seals. J Mammal 78:1101–1116CrossRefGoogle Scholar
  63. Symondson WOC (2002) Molecular identification of prey in predator diets. Mol Ecol 11:627–641CrossRefGoogle Scholar
  64. Takimoto G (2003) Adaptive plasticity in ontogenetic niche shifts stabilises consumer-resource dynamics. Am Nat 162:93–109CrossRefGoogle Scholar
  65. Tollit DM, Steward MJ, Thompson PM, Pierce GJ, Santos MB, Hughes S (1997) Species and size differences in the digestion of otoliths and beaks: implications for estimates of pinniped diet composition. Can J Fish Aquat Sci 54:105–119CrossRefGoogle Scholar
  66. Trivers RL (1985) Social evolution. Benjamin/Cummings Publishing Company, Menlo ParkGoogle Scholar
  67. Van Valen L (1965) Morphological variation and width of the ecological niche. Am Nat 99:377–390CrossRefGoogle Scholar
  68. Voss NA, Nesis KN, Rodhouse PG (1998) The cephalopod family Histioteuthidae (Oegopsida): systematics, biology, and biogeography. Smithson Contrib Zool 586(2):293–372Google Scholar
  69. Warren PH (1996) Structural constraints on food web assembly. In: Hochberg ME, Clobert J, Barbault R (eds) Aspects of the genesis and maintenance of biological diversity. Oxford University Press, Oxford, pp 142–161Google Scholar
  70. Whitehead H, MacLeod CD, Rodhouse P (2003) Differences in niche breadth among some teuthivorous mesopelagic marine mammals. Mar Mamm Sci 19:400–405CrossRefGoogle Scholar
  71. Wikelski M, Wrege PH (2000) Niche expansion, body size and survival in Galápagos marine iguanas. Oecologia 124:107–115CrossRefGoogle Scholar
  72. Williams R (1988) The nearshore fishes of Macquarie Island. Pap Proc R Soc Tasman 122:233–245Google Scholar
  73. Williams RJ, Martinez ND (2000) Simple rules yield complex food web. Nature 404:180–183CrossRefGoogle Scholar
  74. Williams R, McEldowney A (1990) A guide to the fish otoliths from the waters off the Australian Antarctic Territory, Heard and Macquarie Islands. ANARE Research Notes 75, Australian Antarctic Division, KingstonGoogle Scholar
  75. Woodward G, Hildrew AG (2002) Body-size determinants of niche overlap and intraguild predation within a complex food web. Ecology 71:1063–1074Google Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Iain C. Field
    • 1
    • 2
    • 3
    Email author
  • Corey J. A. Bradshaw
    • 1
    • 3
  • John van den Hoff
    • 2
  • Harry R. Burton
    • 2
  • Mark A. Hindell
    • 1
  1. 1.Antarctic Wildlife Research Unit, School of ZoologyUniversity of TasmaniaHobartAustralia
  2. 2.Australian Antarctic DivisionChannel HighwayKingstonAustralia
  3. 3.School for Environmental ResearchCharles Darwin UniversityDarwinAustralia

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