Evidence of abalone (Haliotis rubra) diet from combined fatty acid and stable isotope analyses
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Abalone are common herbivores throughout temperate and tropical waters, and yet the contribution of red and brown macroalgae to the diet of wild abalone remains unclear. In the northern hemisphere, adult abalone are considered to consume predominantly brown algae, but in the southern hemisphere abalone are thought to prefer red algae. Conventional methods such as gut content analysis and feeding trials provide some insight into diet choice, but the associated biases of these techniques create uncertainty surrounding the aforementioned variability in abalone diet. We use combined stable isotope and fatty acid analysis to determine the relative contribution of red algae, brown algae and detritus/microalgae to the diet of wild abalone in Tasmanian waters. Stable isotopes of carbon suggest that brown algae and/detritus are a more important source of carbon than red algae. Fatty acid analysis confirmed the larger contribution of brown algae to the diet of abalone, and also identified the bacterial and diatom component of detritus to be an important contributor to abalone diet. These results show combined use of chemical tracers to be a promising technique for resolving abalone diet, and challenge current perceptions regarding spatial variability in abalone diet choice.
KeywordsDetritus Carbon Isotope Macroalgae Fatty Acid Profile Brown Alga
We thank B. Connell, S. Fava, S. Ibbott, and R. Kilpatrick for assistance in the field. Thanks to G. Edgar and J. Valentine who helped with identification of red algae species. The assistance of B. Mooney, M. Miller, K. Wheatley with laboratory processing and interpretation of fatty acid profiles were especially helpful. Thanks to J. Oakes for advice with analysis of detrital samples. D. Holdsworth managed the CSIRO GC-MS facility. Advice from A Revill was useful in modelling and interpretation of stable isotope values. Comments on the manuscript by C. Mundy, S. Shepherd and two anonymous reviewers are appreciated and helped to improve the manuscript. Thanks to M. Morffew for creating the map.
- Ackman RG, Hooper SN (1973) Non-methylene-interrupted fatty acids in lipids of shallow-water marine invertebrates: a comparison of two molluscs (Littorina littorea and Lunatia triseriata) with the sand shrimp (Crangon septemspinosus). Comp Biochem Physiol 46B:153–165Google Scholar
- Christie WW (1982) Lipid analysis. Pergamon Press, OxfordGoogle Scholar
- Lindberg DR (1992) Evolution, distribution and systematics of Haliotidae. In: Shepherd SK, Tegner MJ, Guzman Del Proo SA (eds) Abalone of the world. Fishing News Books, Carlton, pp 169–181Google Scholar
- Phillips KL, Nichols PD, Jackson GD (2003b) Size-related dietary changes observed in the squid Moroteuthis ingens at Falkland Islands: stomach contents and fatty acid analyses. Polar Biol 26:474–485Google Scholar
- Phleger CF, Nelson MN, Groce AI, Cary SC, Coyne KJ, Nichols PD (2005a) Lipid composition of deep sea hydrothermal vent tubeworms Riftia pachyptila, crabs Munidopsis subsquamosa and Bythograea thermydron, mussels Bathymodiolus sp. and limpets Lepetodrilus spp. Comp Biochem Physiol 141B:196–210CrossRefGoogle Scholar
- Prince J (1989) The fisheries biology of the Tasmanian stocks of Haliotis rubra. PhD Thesis, University of Tasmania, pp 60–70Google Scholar
- Shepherd SA (1975) Distribution, habitat and feeding habits of abalone. Aust Fish 34:12–15Google Scholar
- Shepherd SK, Steinberg PD (1992) Food preferences of three Australian abalone species with a review of the algal food of abalone. In: Shepherd SK, Tegner MJ, Guzman Del Proo SA (eds) Abalone of the world. Fishing News Books, Carlton, pp 169–181Google Scholar
- Stephenson RL, Tan FC, Mann KH (1986) Use of stable carbon isotope ratios to compare plant material and potential consumers in a seagrass bed and a kelp bed in Nova Scotia, Canada. Mar Biol 30:1–7Google Scholar
- Vanderklift MA (2002) Interactions between sea urchins and macroalgae in south-western Australia: testing general predictions in a local context. PhD Thesis, University of Western Australia, PerthGoogle Scholar