Variation in evacuation rates of different foods skew estimates of diet in the western rock lobster Panulirus cygnus
Kris WaddingtonSchool of Plant Biology (M090), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. Email: krisw@cyllene.uwa.edu.au
Marine and Freshwater Research 59(4) 347-350 https://doi.org/10.1071/MF07156
Submitted: 27 August 2007 Accepted: 3 March 2008 Published: 15 May 2008
Abstract
Knowledge regarding differences in evacuation rates of diet items from a consumer’s stomach is important when using gut content analysis to quantify consumer diet. Evacuation rates of three diet items (pilchards, crabs and coralline algae) from the foreguts of western rock lobsters (Panulirus cygnus) were compared in aquaria. To determine evacuation rates, lobsters were allowed to consume offered food over a 90-min feeding period before being killed at 4, 6, 8, 10 and 12 h after the feeding period concluded. Diet items differed in their rate of evacuation from lobster foreguts with coralline algae evacuated most rapidly, followed by crabs, then pilchards. The evacuation of crabs and pilchards was still not complete 12 h after the feeding period concluded. Food not evacuated after 12 h predominantly consisted of hard components of the lobster diet, indicating that it is these components that account for slower evacuation. Observed variation in evacuation rates between diet items may skew the results of studies that use gut content analysis to quantify the diet of western rock lobsters.
Additional keywords: dietary composition, foregut, gut content analysis.
Acknowledgements
I thank Andrew Tennyson and Mathew and Lucas Vanderklift for help collecting diet items. I also thank Mark Rossbach for helping with lobster collection. I thank Mathew Vanderklift, Diana Walker, Andrew Boulton and two anonymous reviewers for providing helpful comments on earlier versions of this manuscript. Funding for this study was provided by the School of Plant Biology at the University of Western Australia. All procedures were approved by the Animal Ethics Committee at The University of Western Australia (Approval number RA/3/100/478) and authorised under state government permits.
Choy, S. C. (1986). Natural diet and feeding habits of the crabs Liocarcinus puber and L. holsatus (Decapoda, Brachyura, Portunidae). Marine Ecology Progress Series 31, 87–99.
| Crossref | GoogleScholarGoogle Scholar |
Haddon, M. , and Wear, R. G. (1987). Biology of feeding in the New Zealand paddle crab Ovalipes catharus (Crustacea, Portunidae). New Zealand Journal of Marine and Freshwater Research 21, 55–64.
Williams, M. J. (1981). Methods for the analysis of natural diet in Portunid crabs (Crustacea: Decapoda: Portunidae). Journal of Experimental Marine Biology and Ecology 52, 103–113.
| Crossref | GoogleScholarGoogle Scholar |
