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Niche overlap and trophic resource partitioning of two sympatric batoids co-inhabiting an estuarine system in southeast Australia
Citation
Yick, JL and Tracey, SR and White, RWG, Niche overlap and trophic resource partitioning of two sympatric batoids co-inhabiting an estuarine system in southeast Australia, Journal of Applied Ichthyology, 27, (5) pp. 1272-1277. ISSN 0175-8659 (2011) [Refereed Article]
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Copyright Statement
Copyright © 2011. The definitive published version is available online at: http://www.interscience.wiley.com
DOI: doi:10.1111/j.1439-0426.2011.01819.x
Abstract
Elasmobranchs play an important role within the trophic
structure of marine ecosystems, but there are relatively few
studies published on the feeding ecology of these species.
Reported herein is the feeding ecology and trophic resource
partitioning of two sympatric batoid species, Urolophus
cruciatus and Narcine tasmaniensis from southeast Australia.
The diet of males and females of both species was similar,
suggesting no sex-specific dietary preferences. Ontogenetic
changes in diet were observed from the diets of both species: as
the body size increased, the proportion consumed of crustacea
to polychaeta decreased. A relatively high degree of niche
overlap (70%) was detected between the trophic resources of
the two species. The way in which the predators partitioned the
resources, however, was significantly different. U. cruciatus fed
predominately on small benthic crustaceans (amphipods and
decapods), while N. tasmaniensis displayed a preference
towards Maldanidae polychaetes. Therefore, although U. cru-
ciatus and N. tasmaniensis both feed predominately on benthic
invertebrates, they specialise on different taxa. This trophic
resource partitioning contributes to the biodiversity of the
region by facilitating the coexistence of these sympatric
species.
The banded stingaree, Urolophus cruciatus and the Tasma-
nian numbfish, Narcine tasmaniensis are two sympatric batoids
widely distributed around the southeast of mainland Australia
from South Australia to New South Wales. Both species are
also found in large numbers in the coastal waters of southeast
Tasmania, and are regarded as among the most common fish
found on soft sediments in the deeper bays of southern
Tasmania (Hutchins and Swainston, 1999; Edgar, 2009). They
are also commonly caught as by-catch from a range of fisheries
throughout their distribution, although incidental mortality
rates have not been quantified for either species.
Both species share several common traits including: a similar
morphology and size as well as co-existing in the same
demersal habitat where they remain relatively inactive, lying
buried in either sandy or muddy substrate for long periods of
time (Edgar, 2009; Last and Stevens, 2009). Given their
commonality, we propose that there is a degree of competition
for resources between the two species.
The objectives of this study were to describe the diet
composition of these two species, and assess the level of dietary
resource partitioning to determine whether this is a potential
mechanism that allows the two species to coexist within the
coastal waters of southeast Tasmania.
Item Details
Item Type: | Refereed Article |
---|---|
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Environmental Management |
Objective Group: | Terrestrial systems and management |
Objective Field: | Assessment and management of terrestrial ecosystems |
UTAS Author: | Yick, JL (Mr Jonah Yick) |
UTAS Author: | Tracey, SR (Associate Professor Sean Tracey) |
UTAS Author: | White, RWG (Professor Rob White) |
ID Code: | 72947 |
Year Published: | 2011 |
Web of Science® Times Cited: | 22 |
Deposited By: | Zoology |
Deposited On: | 2011-09-05 |
Last Modified: | 2017-10-31 |
Downloads: | 4 View Download Statistics |
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