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Analysis of growth and stable isotopes in teeth of male Australian fur seals reveals interannual variability in prey resources

journal contribution
posted on 2014-01-01, 00:00 authored by Travis Knox, H Stuart-Williams, R Warneke, Andrew Hoskins, John ArnouldJohn Arnould
To detect and monitor long-term ecosystem responses to environmental variability, managers must utilize reliable and quantitative techniques to predict future ecosystem responses. Canine teeth from 67 male Australian fur seals (aged 2-19 yr), collected at Seal Rocks, between 1967 and 1976, were measured for relative growth within the dentine growth layer groups (GLGs), as an index of body growth. Fluctuations in relative growth were apparent during 1956-1971, suggesting interannual variation in prey resources within Bass Strait. These were positively correlated with the Southern Oscillation Index and negatively with the Indian Ocean Subtropical Dipole, both on a 2 yr lag. The observed delay may reflect the time required for the nutrient cascade to filter through to the predominantly benthic prey of Australian fur seals. Stable isotope analysis (?15N/?13C) was also used to investigate whether fluctuations in growth were associated with differences in diet. Relative growth was found to be negatively correlated with ?15N, suggesting years of greater resource availability may be associated with individuals consuming proportionally more prey biomass of lower isotopic value. This study demonstrates that fluctuations in the dentine GLGs of male Australian fur seals are related to environmental parameters, suggesting variation in body growth is mediated by changes in prey resources

History

Journal

Marine mammal science

Volume

30

Issue

2

Pagination

763 - 781

Publisher

Wiley-Blackwell Publishing

Location

London, England

ISSN

0824-0469

eISSN

1748-7692

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2013, Wiley