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A prey-related shift in the abundance of small pelagic fish in eastern Tasmania?


McLeod, DJ and Hobday, AJ and Lyle, JM and Welsford, DC, A prey-related shift in the abundance of small pelagic fish in eastern Tasmania?, ICES Journal of Marine Science, 69, (6) pp. 953-960. ISSN 1054-3139 (2012) [Refereed Article]

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Copyright 2012 International Council for the Exploration of the Sea

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DOI: doi:10.1093/icesjms/fss069


Shifts in the relative abundance of small pelagic fish species have signalled a change in the ocean environment in a number of locations. Here we show that the replacement of jack mackerel, Trachurus declivis, with redbait, Emmelichthys nitidus, as the dominant small pelagic species from eastern Tasmania, following a period of high fishing pressure on jack mackerel, is consistent with altered zooplankton communities and long-term climate change. Stomach contents analysis and morphology measurements were conducted on both species to determine if they were functionally equivalent with regard to zooplankton prey. Diet varied between species and with fish size. Krill (Nyctiphanes australis) was consumed by both species, with redbait feeding more heavily on small copepods. The diet overlap and morphometric characteristics indicated that these species are not equivalent with regard to prey and therefore changes in prey availability may have contributed to the observed shifts in relative abundance. The continued poleward extension of the East Australian Current is expected to favour small warm-water copepods; thus, redbait may have an advantage over jack mackerel due to prey preferences. An increase in relative abundance of redbait has decreased effort in surface fisheries and may impact on surface-feeding higher predators in this region.

Item Details

Item Type:Refereed Article
Keywords:climate change, copepods, Emmelichthys nitidus, foodwebs, fisheries, Nyctiphanes australis, Trachurus declivis, zooplankton
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:McLeod, DJ (Mr David McLeod)
UTAS Author:Hobday, AJ (Dr Alistair Hobday)
UTAS Author:Lyle, JM (Associate Professor Jeremy Lyle)
UTAS Author:Welsford, DC (Dr Dirk Welsford)
ID Code:78891
Year Published:2012
Web of Science® Times Cited:21
Deposited By:Zoology
Deposited On:2012-08-01
Last Modified:2013-04-16
Downloads:1 View Download Statistics

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