icolls - Sustainable Tourism CRC

ECOLOGY, THREATS AND MANAGEMENT OPTIONS FOR SMALL ESTUARIES AND ICOLLS
CHAPTER 4 COMPARISON OF DIETS OF FOUR COMMERCIALLY AND RECREATIONALLY
IMPORTANT FISH SPECIES IN TWO ICOLLS IN NORTHERN NEW SOUTH WALES _________ 36
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ABSTRACT ___________________________________________________________________________ 36
MATERIALS AND METHODS ______________________________________________________________ 37
Study Species ______________________________________________________________________ 37
Study Area_________________________________________________________________________ 37
Sampling Methods___________________________________________________________________ 38
Sample Processing___________________________________________________________________ 38
Dietary Analysis ____________________________________________________________________ 38
RESULTS ____________________________________________________________________________ 39
Catch Data _________________________________________________________________________ 39
Dietary Composition _________________________________________________________________ 40
Dietary Breadth _____________________________________________________________________ 43
DISCUSSION __________________________________________________________________________ 44
CONCLUSION _________________________________________________________________________ 45
APPENDIX A: THE INTERMITTENTLY CLOSED AND OPEN LAKES (ICOLLS) SPECIAL
SESSION AT THE ‘ESTUARIES AND CHANGE’ CONFERENCE_____________________________ 46
APPENDIX B: TAXA (SCIENTIFIC AND COMMON NAMES) COLLECTED FROM STUDY
ICOLLS _______________________________________________________________________________ 49
APPENDIX C: ALL ABSTRACTS SUBMITTED TO THE ICOLLS SPECIAL SESSION AT THE
‘ESTUARIES AND CHANGE’ CONFERENCE _____________________________________________ 51
REFERENCES _________________________________________________________________________ 65
AUTHORS_____________________________________________________________________________ 76
LIST OF TABLES
Table 1: Processes threatening the ecological health of ICOLLs _____________________________________ 3
Table 2: Taxa collected from study ICOLLs____________________________________________________ 18
Table 3: Mean and S.E. δ13C values for all food web components sampled from all study ICOLLs.________ 19
Table 4: Mean and S.E. δ15N values for all food web components sampled from all study ICOLLs ________ 21
Table 5: Macroinvertebrate and fish taxa collected from Tallows Creek and Belongil Creek in May 2003 ___ 29
Table 6: Percent contribution of epilithon, filamentous green algae, mangroves and riparian vegetation to
consumers in Belongil and Tallows Creeks, May 2003 ____________________________________ 32
Table 7: Physical properties recorded at the time of sampling for each location ________________________ 38
Table 8: Catch data and individual characteristics for A. australis, P. fuscus, S. ciliata and M. cephalus in
Belongil and Tallows Creek _________________________________________________________ 39
Table 9: Dietary categories in the stomach contents of A. australis and P. fuscus in Belongil and Tallows
Creeks __________________________________________________________________________ 40
Table 10: Dietary categories in the stomach contents of S. ciliata and M. cephalus in Belongil and Tallows
Creeks __________________________________________________________________________ 41
LIST OF FIGURES
Figure 1: Conceptual model of carbon sources and pathways in an ICOLL____________________________ 15
Figure 2: Maps of study ICOLLs in northern New South Wales ____________________________________ 16
Figure 3: Map of study ICOLLs in Byron Bay, New South Wales, Australia __________________________ 27
Figure 4: Mean (± SE) δ 15 N signatures of all food web components collected from both Tallows and Belongil
Creeks in May 2003________________________________________________________________ 30