benefits and challengers (A/Prof Simon Goldsworthy, SARDI) - MISA

Fur seals and sea lions: SouthAustralian icons and sentinelsA/Prof Simon GoldsworthyMISA Ecosystem ServicesTEPS Subprogram

The Australian sea lion: an overview1. Australia's seal heartland2. Bycatch assessment and mitigation3. Habitat modelling and foraging strategies4. Biological sentinels to map change in our oceans

SA – Australia’s Seal HeartlandAustralian fur sealAustraliansea lionRecentlycolonised>85%0 500 1,000New Zealandfur sealkilometres >85%

Post-sealing recovery …or not?New Zealand fur seal:~19,000 pups born annually3.5 fold increase in last 25 yearsPopulation size~ 85-90,000Australian sea lion:~3,000 pups per breeding seasonNot recovering, stable or declining populationPopulation size ~ 11,900 (Threatened Species)

1. Bycatch assessment, mitigation and managementCommonwealth Managed (AFMA)Demersal gillnet shark fisheryFishing effort 2006-2009Average effort ~100,000 km.hrs/yrASL foraging densityCircumstantial evidence that lack ofrecovery/decline in sea lions was dueto bycatch in gillnet fisheriesModelling of foraging effort identifiedconsiderable spatial overlap withfishing effort~1.62 million seal days/yrPhoto D Hamer

1. Bycatch assessment, mitigation and managementObserved net haulObserved net haul with ASL bycatch mortalityASL colonyBycatcheffortper unit of fishingProbability of encountering sealsIndependent observer data• Feb 2006- Jan 2008• 234 net-hauls (2.4% fishingeffort)• bycatch • 789 km mortality net-setrates highly correlated with estimated ASL foraging density• provides • 12 ASL a mortalities tool to estimate bycatch from any distribution of fishing effort• bycatch • 0.013 ASL/km of individuals net-set (females and males) can be apportioned back toindividual • 2 landed, subpopulations10 (83%) drop-outsZero Low Medium High

1. Bycatch assessment, mitigation and managementProvided estimates of impact on sea lion populationsBycatch levels unsustainable 270- 500 sea lion mortalities per 18 month breeding cycleProvided range of mitigation options and estimates of their effectivenessFishery closures based on core foraging areas, distanceand depth rangesAdvised on and assessed management strategiesIndependent observer program, closurestrategies, bycatch trigger limits,assessment and monitoringOutcomes: major reduction in fishingeffort and sea lion bycatch mortality

2. Habitat modelling, foraging strategiesGPS tracks form 7 ASL females –Nuyts ArchipelagoFatsLoc GPS tagsMore data, higher precisionEnable finer scale habitat analyses

Crittercam data in has been used to map benthichabitats as part of marine planning processProvide alternate predator perspective of habitatquality vs. anthropocentric approaches

3. Biological sentinels to map change Australia’s ocean environment>500 deploymentson 7 speciesGAB has highest density ofpelagic predators inAustralia’s s coastal waters• What are the key physical oceanographic features that underpin the distribution, foraginglocations, movements and migratory patterns of apex predators?• How do foraging distributions and movements of different apex predator species respond tochange in the ocean environment?

3. Biological sentinels to map change Australia’s ocean environment• animal borne sensors interactwith both physical and biologicaloceanographic features• add observational power at placesand times not possible with otherplatforms• they directly target ecologicallyimportant regions where informationof oceanography is most needed• can collect physical data at anunprecedented temporal andspatial scaleMonitoring of spatial and temporal extent ofupwelling in eastern GAB

AcknowledgmentsObservations – future directionsBrad PagePaul RogersInteractions between apex predatorsAndrew Lowtherand their environment provide aCharlie Huveneersunique means to understand the keyPeter ee Shaughnessyecological and oceanographicMISAprocesses that underpin our uniqueFisheries Research & Development CorporationAustralian Marine Mammal Centre (DSEWPC)marine ecosystemsDepartment t of Environment, Water, Natural ResourcesPIRSA Fisheries and AquacultureDevelopments in biologging technology willAFMAmean that marine animals will increasingly gyIMOSbe mapping and monitoring our marineSA Seafood Industryecosystems for usSA MuseumUniversity of AdelaideFlinders UniversityitUniversity of TasmaniaMacquarie UniversitySea World Research and Rescue FoundationAustralian Antarctic DivisionSA Nature Foundation