The ecology of fish larvae in Pumicestone Passage : an estuarine system in Southeast Queensland, Australia

Pham, Cong Tri. (2002). The ecology of fish larvae in Pumicestone Passage : an estuarine system in Southeast Queensland, Australia PhD Thesis, School of Integrative Biology, The University of Queensland.

       
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Author Pham, Cong Tri.
Thesis Title The ecology of fish larvae in Pumicestone Passage : an estuarine system in Southeast Queensland, Australia
School, Centre or Institute School of Integrative Biology
Institution The University of Queensland
Publication date 2002
Thesis type PhD Thesis
Supervisor Greenwood, Jack
Total pages 198
Collection year 2002
Language eng
Subjects L
270702 Marine and Estuarine Ecology (incl. Marine Ichthyology)
630302 Fisheries-recreational
Formatted abstract
The ecology of larval fish within the northern half of Pumicestone Passage was investigated over a two year period to examine their distribution along the axis (horizontal distributions), and for one year, variations between surface and bottom waters (vertical distributions).

A total of 89,816 individual of fish larvae from 37 families and 74 taxa was caught. There were no significant differences in the distributions of fish larvae between monthly-fortnightly sampling intervals and between surface and bottom water layers. However, fish larvae were more abundant during the warm temperature period at all sampling sites. The variation in water temperature throughout the study period was the main contributing factor to the variations of fish larvae, temporally. Fish larvae were more abundant in the mid-estuary region where tidal velocities are low. Species diversity was highest in summer (temporal) and near the estuary mouth (spatial) which suggested that the spawning of most marine fish species occurred in spring and outside the estuary.

Use of the Pumicestone Passage differed among those larval fish species examined. Gobiids (Gobiopterus semivestit), considered as the estuarine species, spawned and spent their entire life within the system. In contrast, the clupeoids (Hyperlophus translucidus, Engraulis australis) and sillaginids (Sillago ciliate) spawned outside the estuary, and after hatching their larvae entered the system., utilised the area for food and shelter and they gradually returned to the open sea as they grew. Results from this investigation are in agreement with studies by the Queensland Department of Primary Industries showing that the clupeoids spawned just outside the estuary but used the estuary for the development of their early life stages. A 24-hour sampling survey was carried out for the investigation of the feeding activity of Sillago ciliata in the estuarine system. Evidence from analyses of stomach contents showed S. ciliata larvae feed mainly in the late afternoon hours and they do not feed at night. This is evidence that larvae of this species rely on vision for feeding once the yolk-sac has been absorped. Small larvae of this species spend their earliest developmental stage (TL < 13 mm) in the water column where they feed on epiplanktonic copepods. After settlement (TL > 13 mm), they switch to benthic copepods and then to nematodes as they grow.

Results from this study suggested that Pumicestone Passage plays an important role in supporting the local fish population.
Keyword Larvae
Fishes -- Habitat -- Queensland -- Pumicestone Passage
Fishery resources -- Queensland -- Pumicestone Passage

Document type: Thesis
Collection: UQ Theses (RHD) - UQ staff and students only
 
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Created: Fri, 24 Aug 2007, 17:51:16 EST