The feeding ecology and physiology of vagrant Chaetodon species on temperate New South Wales reefs Marcus A Gregson Dept Environmental Sciences Institute for Water and Environmental Resource Management University of Technology, Sydney Supervisors: Professor David J Booth (UTS) Dr Morgan S Pratchett (James Cook University)

Introduction East Australian Current Vagrant Species CSIRO Images Heath Folpp, NSW Fisheries

Feeding Interactions Morphological FactorsEnvironmental Factors Body size and energy needs Digestive/ buccal system Presence of suitable prey Environmental conditions Prey Intake Growth and Condition Adapted from Drickamer et al 2002 Competitors Predators Social Factors

Current Study Latitudinal differences in feeding ecology of juvenile Chaetodons H 0i : Chaetodon diet does not differ between tropical and temperate regions H 0j : Difference in diet does not affect Chaetodon growth or condition

Study Species Randall JE, Chaetodon aurigaChaetodon flavirostris Family: Chaetodontidae

Methods Locations Sydney (3 sites) One Tree Island (3 sites) Melbourne Canberra SYDNEY Newcastle Brisbane ONE TREE ISLAND Rockhampton Townsville Cairns Hobart

Methods H 0i : Chaetodon diet does not differ between tropical and temperate regions Food Intake: Bite Rate Potential Prey: Grazing Surface Actual Diet: Gut Content Analyses H 0j : Difference in diet does not affect Chaetodon growth or condition Body Condition: Fulton’s Condition k

H 0i : Chaetodon diet does not differ between tropical and temperate regions Bite Rate n=42 n=16 n=27 n=10 Factorp Location0.293 Species0.829 Location*Species0.547

C. flavirostris Sydney C. auriga

One Tree Island C. auriga C. flavirostris

Prey Items Found in the Field 1 mm

Gut Content Analyses: Chaetodon auriga Mean Volume at Sydney and One Tree Island Sydney Ranking Index (occurrence X volume) (Harmelin-Vivien & Bouchon-Navaro 1983) Coral0 Unidentified316 Crustacea160 Polychaete9221 Polychaete Setae13 1 mm n=9 n=11

H 0i : Chaetodon diet does not differ between tropical and temperate regions Gut Fullness: Chaetodon auriga t = 3.04, df=11, p= n=9 n=11 t= -3.04, df= 12, p= 0.005

H 0j : Difference in diet does not affect Chaetodon growth or condition Fulton’s Condition k: C. auriga k= 10 5 *[w/l 3 ] t=1.77, df=13, p=0.359 n=9 n=13 t= 0.369, df=13, p=0.36

Summary and Future Research Food Intake: Bite rate does not differ between Sydney and One Tree Island -Gut fullness of Chaetodon auriga in Sydney suggests there is ample food available Potential Prey: Chaetodon species at both Sydney and One Tree Island exploit habitats of high macroinvertebrate diversity and abundance Diet: Sydney Chaetodon auriga appear to eat a much higher volume of polychaetes than those at One Tree Island Body Condition: Despite this variation in diet, no difference in body condition

Acknowledgements Research was supported by an ARC Discovery Grant (DP D Booth) “The mechanisms of settlement success in coral reef fishes” Matt and Ali at One Tree Island Research Station Pat Hutchings at Australian Museum for polychaete ID assistance