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Natural Diet of an Australian Freshwater Pipefish

Andrew W. Jones¹, Lars G. Rudstam¹ & Thomas S. Rayner²

Correspondence: (Login to view email address)

1. Cornell University
2. James Cook University

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Document Type:

Poster

Date:

Received 03 July 2007 00:08 UTC; Posted 03 July 2007

Subjects:

Ecology

Tags:

• endangered species
• Ecology
• fish
• niche

Abstract:

Globally, the family Syngnathidae (seahorses and pipefish) is recognized as being both under threat from anthropogenic pressures and poorly studied. Of the 47 species that are listed on the IUCN Red List, 33 are currently listed as ‘data deficient’, with inadequate information available to make an assessment of their risk of extinction. Within Australia, this has prompted environmental assessments of specific fisheries, as well as a number of recent ecological studies of marine syngnathids. However, no work has been published on the continent’s four freshwater species. To begin to remedy this, a thorough analysis of the feeding habits of one such species was conducted. Twenty-two specimens of Hippichthys heptagonus Bleeker, 1849 were collected from the Mulgrave River in north Queensland. Dissection and subsequent analysis revealed that microcrustaceans comprised the vast majority of the species diet, with calanoid and cyclopoid copepods being by far the most prevalent prey items (66%). Dipteran, as well as ephemeropteran, larvae were moderately abundant (5% and 10%), and made a notable contribution to the volume of the average diet (16% and 12%). A percent principal component analysis of the volume data reinforced these findings. The first factor accounted for 69.7% of the observed variation, with largest factor loading (0.88) belonging to copepods. there were no significant differences in prey consumption Between genders, but, the percent volume of copepod prey significantly higher in adults was than in juveniles (Mann-Whitney’s U: P < 0.01). These findings indicate that H. heptagonus is primarily a predaceous planktivore, with a specialized diet that is comparable to coastal marine syngnathids. Also, the prevalence of a single prey type suggests that the H. heptagonus occupies a narrow ecological niche, and that its distribution within the watershed may be limited by prey availability.

Presented at:

Cornell University Honors Thesis Presentation, 28 May 2006

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This document is licensed to the public under the Creative Commons Attribution 2.5 License

How to cite this document:

Jones, Andrew, Rudstam, Lars , and Rayner, Thomas. Natural Diet of an Australian Freshwater Pipefish. Available from Nature Precedings <http://dx.doi.org/10.1038/npre.2007.329.1> (2007)

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