CENTRE FOR AQUATIC POLLUTION IDENTIFICATION AND MANAGEMENT, TECHNICAL REPORT #26 DETERMINING THE SPECIFICITY OF FISH-HABITAT RELATIONSHIPS IN WESTERN PORT Determining the specificity of fish-habitat relationships in Western Port Greg Jenkins, Tim Kenner, Andrew Brown August 2013 1 CENTRE FOR AQUATIC POLLUTION IDENTIFICATION AND MANAGEMENT, TECHNICAL REPORT #26 DETERMINING THE SPECIFICITY OF FISH-HABITAT RELATIONSHIPS IN WESTERN PORT Contents List of Tables .................................................................................................................................................. 4 Introduction .................................................................................................................................................... 8 Study Objectives ................................................................................................................................... 10 Materials and Methods ................................................................................................................................. 12 Sampling Locations .................................................................................................................................. 12 Sampling Methods .................................................................................................................................... 12 Stereo video sampling .......................................................................................................................... 12 Mini Otter Trawl Sampling .................................................................................................................. 13 Laboratory Methods ................................................................................................................................. 13 Data Analysis ............................................................................................................................................ 14 Results .......................................................................................................................................................... 18 Underwater Stereo video .......................................................................................................................... 18 Mini Otter Trawl ....................................................................................................................................... 35 Discussion ..................................................................................................................................................... 52 Specificity of fish habitat relationships in Western Port .......................................................................... 52 Resilience of fish populations to habitat loss through the use of alternative habitats .............................. 54 Understanding and Refinement of Asset Areas from the Perspective of Fish Biodiversity ..................... 55 Conclusions .................................................................................................................................................. 56 Acknowledgements ...................................................................................................................................... 58 References .................................................................................................................................................... 59 2 CENTRE FOR AQUATIC POLLUTION IDENTIFICATION AND MANAGEMENT, TECHNICAL REPORT #26 DETERMINING THE SPECIFICITY OF FISH-HABITAT RELATIONSHIPS IN WESTERN PORT List of Figures Figure 1. Habitats recorded by underwater survey in Western Port (Blake et al. 2012). A. Amphibolis antarctica , B. Caulerpa cactoides , C. Rhodolith bed, D. Reef with macroalgae, E. Invertebrate (Bryozoan) isolate................................................................................................................................. 11 Figure 2. Sampling Locations in Western Port. Stars, Amphibolis habitat; Cross, reef-macroalgae; Circles, Sendentary invertebrate isolates; Triangles, Caulerpa habitat; Diamond, Rhodolith beds. ................. 15 Figure 3. Deployment of stereo video camera frame ................................................................................... 16 Figure 4. Diagram of mini otter trawl net employed to sample in Western Port, a) main body of net and liner (net – 38.1 mm aperture knotted nylon; liner - 5 mm aperture knotted nylon); b) codend bag of net and liner (net – 31.75 mm aperture knotted nylon; liner – 3 mm aperture knotless nylon); c) wooden otter-boards – 61 cm x 31 cm weighted with lead sheets; d) tickler chain; e) head rope – 390 cm; f) 4 foam floats; g) foot rope and chain (390 cm); h) bridle ropes; i) alternate retrieval line. ...... 17 Figure 5. Mini otter trawl net deployed in Western Port .............................................................................. 17 Figure 6. Average (±1 SE) Species Number of fish recorded on underwater stereo video .......................... 23 Figure 7. Average (±1 SE) Time in View of total fish recorded on underwater stereo video ...................... 24 Figure 8. Average (±1 SE) Time in View of Sixspine Leatherjacket, Meuschenia freyceneti , recorded on underwater stereo video ........................................................................................................................ 24 Figure 9. Average (±1 SE) Time in View of Weedy Seadragon, Phyllopteryx taeniolatus , recorded on underwater stereo video ........................................................................................................................ 25 Figure 10. Average (±1 SE) Time in View of Bluethroat Wrasse, Notolabrus tetricus, recorded on underwater stereo video ........................................................................................................................ 25 Figure 11. Average (±1 SE) MaxN of total fish recorded on underwater stereo video ............................... 26 Figure 12. nMDS plot of log(x+1) transformed Time in View data for fish recorded on underwater stereo video ..................................................................................................................................................... 27 Figure 13. Average (±1 SE) Length of fish recorded on underwater stereo video ....................................... 28 Figure 14. Length-frequency distributions for total fish recorded on underwater stereo video ................... 29 Figure 15. Length-frequency distributions for Meuschenia freycineti recorded on underwater stereo video .............................................................................................................................................................. 30 Figure 16. Length-frequency distributions for Notolabrus tetricus recorded on underwater stereo video .. 31 Figure 17. Length-frequency distributions for Phyllopteryx taeniolatus recorded on underwater stereo video ..................................................................................................................................................... 32 Figure 18. Length-frequency distributions for Acanthaluteres sp . recorded on underwater stereo video ... 33 Figure 19. Average (±1 SE) species number of fish collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ................................................................................................................ 41 Figure 20. Average (±1 SE) abundance of total fish collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ................................................................................................................ 41 Figure 21. Average (±1 SE) abundance of leatherjackets, Acanthaluteres sp., collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ....................................................................... 42 Figure 22. Average (±1 SE) abundance of Cobbler, Gymnapistes marmoratus , collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ............................................................ 43 Figure 23. Average (±1 SE) abundance of Little Weed Whiting, Neoodax balteatus , collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ............................................................ 43 Figure 24. Average (±1 SE) abundance of Spotted Pipefish, Stigmatopora argus , collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ............................................................. 44 3 CENTRE FOR AQUATIC POLLUTION IDENTIFICATION AND MANAGEMENT, TECHNICAL REPORT #26 DETERMINING THE SPECIFICITY OF FISH-HABITAT RELATIONSHIPS IN WESTERN PORT Figure 25. Average (±1 SE) abundance of Grass Whiting, Haletta semifasciata , collected by mini otter trawl. NB Hastings-SG location was only sampled in autumn ............................................................. 44 Figure 26. nMDS plot of log(x+1) transformed abundance of fish collected by mini otter trawl ................ 45 Figure 27. Average (±1 SE) length of fish collected by mini otter trawl ..................................................... 46 Figure 28. Length-frequency distributions for total fish collected by mini otter trawl ................................ 47 Figure 29. Length-frequency distributions for Stigmatopora argus collected by mini otter trawl .............. 48 Figure 30. Length-frequency