1. Euryhaline elasmobranchs are sharks and rays that utilise estuarine environments.

2. Ecological Niche Describe abiotic and biotic variables that affect an organism and how that organism then affects those same variables (Chase & Leibold 2003; Hirzel & Le Lay 2008; Hutchinson 1957; McInerny & Etienne 2012).O HNCNHabitat 3. Fundamental and Realized Niches 2 ways the niche is describedFundamentalWhy are penguins absent? Niche WidthRealized 4. Significance of Elasmobranchs Ecologically Apex & meso predators - extensive role in ecosystems (McDavitt, 1996) Based on Pen Tsao Kang Mu (pharmacopeia)Culturally Many coastal societies have stories /legends E.g. PNG, Australia Yolngu & Angurugu, Africa, China, Borneo, even Europe/UK EconomicallyArtist: Nekingaba Maminyamanja, Date: c. 1980. McDavitt (2005) Fishing, curios, tourism, herbal medicine, food Li Livres dou Tresor codex, facsimile di M. Moleiro: fol. 45v 5. Importance of Predators Top down effect in food webs Reductions - serious ramifications for ecosystems (Estes et al. 2011) E.g. Chesapeake Bay, USA scallop industry decimated (Myers et al. 2007)Apex predators (Makos, Hammerheads Whalers) eat raysOver fishing + habitat degradationMeso predator Cownose Ray eats OystersPopulation explosionOyster bed healthyDecimated bivalves 6. Elasmobranchs (sharks and rays) Predators at risk. Indo- Australian at RiskNorth Central American Species at Risk Concern 14%60% not at riskConcern 40%86% not at riskWhy at Risk? Anthropogenic influences e.g. fishing & habitat destruction (Cavanagh et al. 2003; Myers et al. 2007)(Baum & Worm 2009; Dulvy et al. 2008; Kyne et al. 2012; Myers et al. 2007; White & Kyne 2010).Why Important? Key roles in marine ecosystems & communities Influence species diversity, population sizes & prey (Corts 1999; Heithaus et al. 2008) 7. Trophic Niche - Diet Assists in determining effect of species lossBearhop et al. (2004) conceptual framework 3 broad types of consumers: Specialists - narrow range of prey Generalists Type A - wide range of preyType B generalists individuals eat specific prey from wide range of itemsFigure 1: Representation of the differences between feeding types in consumer populations. (Bearhop et al. 2004) 8. Spatial Niche Space Usage Is influenced by: species dispersal conducive environmental conditions & resources for survival reproduction interspecific interactions (predators, pathogens) Habitat specialists - more at risk (Arakaki & Tokeshi 2010; Hirzel & Le Lay 2008; Sobern 2007; Pulliam 2002) 9. Indigenous Communities & Euryhaline Elasmobranchs 85% of coastal and estuarine environments Norma Joshua in Normand 2004 Knowledge of NT ecosystems extensive & historic Are culturally (totemic) & economically significant Australias indigenous harvest preliminary estimates only Extent, impacts & data lacking. (Ens 2012; Altman, Buchanan & Larsen 2007; McDavitt 1996, 2005; Waddy 1988; Heath 1980, 1988) 10. http://cheekydancers .wordpress. Com/original-dance-history/Indigenous Ecological Knowledge (IEK)http://jobs.nsw.gov.au/ Accumulated knowledge of species based on oral histories & information transferred through past generations (TEK or IEK) Interconnected science and cultural knowledge systems Observations from 1000s of years of living in an environment can be applied to western niche concept particularly spatial niche (Berkes 2008; Horstmann & Wightmann 2001)http://glucoensuremd.com/2/aboriginal-men-huntinghttp://www.janesoceania.com/australian_aboriginal_anthropology/index1.htm 11. Examples of IEK Cyclic patterns Caribou, Canada (Ferguson, Williamson & Messier 1998),Medicinal plants in Mexico (Yucatn) (Hunn 2001; Nabhan 2001)Fire management techniques (Russell-Habitat preferences, Puerto Rico (Garca-Quijano 2007)Smith, Whitehead & Cooke 2009Co-management Great Barrier Reef (George, Innes & Ross 2004; Nursey-Bray 2009) 12. Two way learning Indigenous & non-Indigenous people share knowledge Contribute historical & observational data (Ens, 2012) Australian studies using this method: The habitat, diet & behaviour of Rock-Wallabies (Telfer & Garde 2006) Reptile behaviour, movement & distribution (Baker 1992) 13. Two Way Tool Box How important is the freshwater environment in the ecology of euryhaline elasmobranchs ?IEK Interviews Cultural MappingUnderstanding:Trophic Niche & Spatial NicheStable Isotope AnalysisAcoustic Tagging Lipid Analysis 14. Euryhaline Elasmobranchs Tolerate a range of salinities Highly specialised life histories Global decline due to: Rapid human population growth Disturbance (Compagno 2002; Compagno & Cook 1995) Rare, threatened & data-poorSmalltooth Sawfish, Pristis pectinata USA 15. Why study spatial & trophic ecology in NT? Legal fisheries 10 cause of sawfish decline NT riverine environment near pristine Critical habitats / key prey species Accurate management plans Bull Shark Carcharhinus leucas Speartooth Shark Range of species Glyphis glyphis Freshwater Sawfish Pristis pristisNorthern River Shark Glyphis garricki Dwarf Sawfish Pristis clavataFreshwater Whipray Himantura dalyensis 16. NT Rivers Massive tidal ranges, increasing salinity (dry season) & extensive mangrove forests Remote & difficult to access Near Pristine (more data needed on impacts) Feral animals, weeds, development, agriculture & mining International strongholds for aquatic biodiversity 17. Trophic niche of euryhaline elasmobranchs Diet from X- rays & gut content analysis Detrital matter G. garrickiOtherP. pristisP. pristisG. garricki P. pristisP. clavata C. leucasC. leucasC. leucasC. leucasC. leucas From Stable Isotope Analysis: Pilot study: dietary & habitat overlap within sawfish P. pristis and P. clavata different from A. cuspidata. USA C. leucas: Evidence of Type B generalists with individual specialization 18. Spatial niche of euryhaline elasmobranchs. Movement & Distribution Studies Distribution: - rivers, estuaries & coastal areas of northern Australia P. pristis - WA acoustic tagging, conventional tags, some genetic work C. leucas - genetic studies , habitat partitioning & directly from acoustic tagging in South QLD & USA Tillet (2011) dissertation NT Only C. leucas study in near pristine riversystems (Peverell 2005; Pillans et al. 2009; Stobutzki et al. 2002; Thorburn et al. 2008; Thorburn et al. 2003; Thorburn & Rowland 2008; Whitty et al. 2009). 19. IEK knowledge of Elasmobranchs in NT Limited IEK on shark & ray species particularly in NT Sea country people have deep totemic connections (e.g. Ngukurr, Groote) more knowledge exists? Intact cultural landscapes of the NT Potentially inform management of river & estuaries(McDavitt 1996, 2005; Waddy 1988) 20. Aims 1. To determine the inter- and intra-specific trophic niches of euryhaline elasmobranchs in NT tropical aquatic ecosystems. 2. To determine the spatial niche (i.e. movement and habitat use) of a model euryhaline elasmobranch species (the bull shark, C. leucas). 3. To record indigenous knowledge & the ecological & cultural role of euryhaline elasmobranch species. 21. To determine the inter- and intra-specific trophic niches of euryhaline elasmobranchs in NT tropical aquatic ecosystems. Null Hypotheses: i. ii.Different species (e.g. P. pristis, C. leucas, G. glyphis and G. garricki) will be dietary specialists and have distinct partitions from each other. There will be no intra-specific dietary specialization within species. 22. Trophic Methods Fatty acid (FA) & stable isotope (SIA) analysis Fish caught using: Hook and line (barbs removed), gill nets 4 -7 inch, demersal (bottomset) 20 hooks & Cast nets Primary producers & invertebrates also sampled Muscle tissue - longer turn over (more effective for diet) & if any unforseen mortalities - liver tissue 20 -30 individuals Potential prey collected for SIA & fatty acids 5 representativesCaudal Peduncle site of biopsy 23. Stable Isotope Analyseshttps://www.niwa.co.nz/publications/wa/vol12-no1-march-2004/shortfin-eels-in-tewaihoraNitrogen fractionates & becomes enriched up the food chain (Post 2002)Trophic niche of species can be determined by comparing prey spps (Hussey et al. 2012). 24. Lipid Analysis Marine algae synthesize lipids Vertebrates ingest lipids from food chainCell membranes & adipose tissue significantly influenced by consumption (Sargent, Tocher & Bell 2002). 25. Trophic Analysis Mixing Models Determine proportions of food to reconstruct diet Inclusion of fatty acids refines model Important to exclude confounding influences urea, lipids Trophic position estimate formula TP elasmobranch = (15N elasmobranch 15N baseline organism)(15N)1 + TP baseline organism 26. To determine the spatial niche (i.e. movement and habitat use) of a model euryhaline elasmobranch species (the bull shark, C. leucas) Null Hypothesis: C. leucas will be a habitat generalist and will not display habitat specialization. 27. Defining spatial niche using acoustic tagging 30 C. leucas tagged with acoustic transmitter in abdominal cavity ping is received by an acoustic receiver 33 acoustic receivers (NERP) South Alligator River physical parameters 28. South Alligator River Location of acoustic receivers = Acoustic ReceiverArnhem HighwayYellow WatersMap from Richard Pillans - CSIRO 29. Analysis of Spatial Data Range testing acoustic receivers Extent & timing of movement Analyse correlations between movement & habitat type, salinity, seasons, lunar cycles, tides Find habitat preference & possible influences to that preference 30. To record indigenous knowledge & the ecological & cultural role of euryhaline elasmobranch species. 31. On preliminary visit people were willing to share knowledge of sightings of Sawfish and potential habitat. 32. Study Background of communityImplement tools in communal areasReflect & adjust tools on recommendationsIEK Methods Participatory Action Analyse data Research (PAR) determine whomDetermine stakeholders, format plan, request permissionsInput from elders, Yugul Mangi Rangers & communityto interview furtherFormat semi structured questions Develop brief survey tool consisting of timelines and mapsWrite up including report for communityAnalyse data / draftCarry out interviews(Chevalier & Buckles, 2012; Baum, MacDougall, Smith 2006) 33. Semi-Structured Interviews Open questions - encourage discussion & range of topics Interviews on country (if possible), approx. 1 hour, with refreshments Interviewees dependant on number of knowledge holders Electronically recorded Ngukurr Language Centre Payment offered to interviewees(Grenier 1998; Huntington 2000; Weiss, Hamann & Marsh 2012) 34. Yugul Mangi Land & Sea Rangers as research assistants Potentially collect samples from community Safety on country (e.g. river and road hazards) Help identify key people with cultural rights to share knowledge Relationship building within community 35. TimelinePresentations Poster OCS/ASFB conference - July 2012 Talk People in Land & Sea conference September - 2012 Poster ESA conference- December 2012 36. Significant Partners & Ethics NAMRA scholarship $15 000 operation costs / year NERP Marine Biodiversity Hub (CDU, NT Fisheries) will contribute: field support, transport, tissue collection and the use of acoustic receivers. Co- authorship offered to significant contributors ie The Yugul Mangi Land and Sea Rangers publication they will be listed as co-authors. Stable isotope analysis Australian Institute of Marine Science (AIMS) at the Arafura Timor Research Facility (ATRF) Fatty Acids will be analyzed with assistance from Dr. Peter Nichols of CSIRO Hobart. NLC research permit: In Progress S17 NT fisheries approved: S17/3268 Animal ethics approved: A12016 Human ethics approved: H12117 37. Acknowledgements Thankyou to everyone who has provided advice, assistance & support! NAMRA Supervisors NERP Peter Kyne Collection of samples & acoustic study ATRF / AIMS CSIRO Peter Nichols NT Fisheries (Grant Johnson) Yugul Mangi Rangers Ngukurr Community Robertson Family - Ngukurr