ABALONE Preparing fisheries for climate change

South East Australian Program
Preparing fisheries for climate change
ABALONE fact sheet
Temperatures recorded off the east coast of Tasmania over the
last 70 years have shown that this region is warming at 3.8 times
the global average.
Over the next century, the marine systems of south-east Australia
are expected to continue exhibiting some of the largest climatedriven changes in the Southern Hemisphere, with substantial
changes to ecosystems. The subsequent flow-on effects to
communities and businesses will depend, in part, on how well
fishing industries and resource managers can adapt to these
challenges.
Abalone was one of four case-study fisheries selected to identify likely effects of climate change and
highlight how fishery assessment and management frameworks could be adjusted to better consider
climate change.
About the case study
The fishery
Abalone resources support important
commercial and recreational fisheries
across Western Australia (WA), South
Australia (SA), Victoria (Vic), New South
Wales (NSW) and Tasmania (Tas).
Two of the most commercially important
species are blacklip abalone (Haliotis
rubra) and greenlip abalone (H.
laevigata). These species dominate the
catches, accounting for 82%, and 15%
of wild abalone production in Australia,
respectively.
Blacklip abalone are harvested
commercially across all four southeastern states (NSW, VIC, TAS, and SA),
while greenlip abalone are harvested in
VIC, TAS, SA and WA.
Abalone is the second most valuable wild
fisheries product in Australia after rock
lobster. The total annual catch is
approximately 4500 tonnes with an
estimated annual gross commercial value
of AUS$200 million.
Fishing involves divers hand-harvesting
the product from reefs at water depths
from 1 to 40m. The fisheries are
managed separately within each
jurisdiction using tools comprising both
input (e.g. limited entry to the fishery)
and output (e.g. minimum legal sizes,
total allowable commercial catches
(TACCs)). Collectively these have been
largely successful with Australian
abalone production generally
sustainable in comparison to fisheries for
these molluscs elsewhere.
An extensive review of the literature
identified that abalone have reduced
ability to cope with warm water
temperatures and increased
acidification. Blacklip abalone have a
lower preferred water temperature and
a lower thermal tolerance than greenlip.
This project was the first to examine
environmental drivers of fishery
production across the range of the
Australian abalone fisheries and across
all available environmental data
including sea surface temperatures,
salinity, tidal flow and swell.
Relationships between environmental
factors and fishery production were
examined at spatial scales consistent
with abalone stock structure.
How changes in the physical environment may
affect abalone production
((((Determining(the(extent(to(which(climate(change(may(influence(
Australian(abalone(stocks(was(challenging.(Abalone(stocks(and(
fisheries(are(likely(to(be(influenced(by(three(aspects(of(climate(
change:(
((
T1- gradual(increases(in(water(temperature(and(ocean(acidification;(
T2- increased(frequency(and(magnitude(of(extreme(events(Te.g.(
marine(heat(waves-;(and
T3- changes(in(the(distribution3(abundance(or(activity(of(competitors(
and(predators(Te.g.(range(extension(of(the(long-spined(sea(
urchin(Centrostephanus rodgersii-.(Collectively(these(are(likely(to(
result(in(reduced(productivity(and(catches(of(abalone.
The(future(productivity(of(abalone(fisheries(in(the(south-east(will(be(
impacted(by(climate(change(through(a(combination(of(slower(growth(
rates(and(increased(frequency(of(mortality(events.
At(warmer(summer(temperatures(the(size(of(abalone(at(
reproductive(maturity(and(the(maximum(sizes(obtained(were(
smaller(than(those(at(cooler(summer(water(temperatures.
(
For(blacklip3(warmer(water(temperatures(during(summer(were(
typically(associated(with(lower(blacklip(catches(Thowever3(there(
were(exceptions(to(this(pattern-.
(
Relationships(between(greenlip(catches(and(the(oceanographic(
variables(considered(in(this(study(were(less(clear(than(those(for(
blacklip3(but(the(general(overall(trend(was(for(larger(greenlip(
catches(to(have(been(obtained(from(those(areas(with(T1-(slower(
tidal(flow(rates;(and(T2-(relatively(stable(water(temperatures(
with(a(low(incidence(of(more(‘extreme’(temperatures3(eg(
absence(of(very(high(or(very((cold(summers(or(very(cold(winter(
temperatures.(
SummaryxofxlifexcyclexofxHaliotisxsp.,xandxpointsxofxexposurextoxrelevantx
climatexchangexdriversxorxknownximpacts.
Vulnerability of assessment and management
systems to climate change
xxxxxExistingxmanagementxsystemsxappearxrobustxtoxclimatexchange,xevenx
thoughxtheximpactsxofxclimatexchangexonxthexabalonexstocksxisxunlikelyxtox
bexuniformxinxtimexorxspace.xThisxisxbecausexU1zxcurrentxassessmentsxinxallx
jurisdictionsxarexundertakenxatxappropriatexspatialxscalesxandxU2zxitxisx
likelyxthatxthexcurrentxmeasuresxofxstockxstatusxUi.e.xCPUExasxanxindexxofx
relativexabundance,xsizexstructurexofxthexcommercialxcatch,xdensityx
estimatesxfromxfishery-independentxsurveyszxwillxremainxsuitable.xxx
NewxindicesxUe.g.xspatialxperformancexindicatorsz,xmayxprovidex
valuablexadditionalxinsightsxandxprovidexcapacityxtoxmapxfine-scalex
changesxinxproductivity.xx
ReferencexpointsxandxdecisionxrulesxforxthexAustralianxabalonexfisheriesx
arexreviewedxonxanxongoingxbasisxandxthexpotentialximpactsxofxclimatex
changexarexaxcomponentxofxthisxprocess.xx
EEEEE
Knowledge requirements into the future
ToEmaximiseEourEunderstandingEofEanyEfutureEchangesEinEtheEabaloneEfisheryEweE
need:
in situEwaterEtemperatureEmonitoring
EEEperiodicEsamplingEofEabaloneEtoEmonitorEchangesEinEgrowth-rates,EsizeE
EEEatEmaturityEandEabundance
EEEharvestEstrategiesEthatEareEtestedEusingEmanagementEstrategyE
EEEevaluationE(MSE)EtoEensureEresponsivenessEtoEchangesEinEstockE
EEEabundanceEandEproductivity
EEEgreaterEunderstandingEofEkeyEenvironmentalEdriversEofEabaloneEbiologyEEE
Ensuring that the fisheries of south-east Australia adapt effectively to
climate change will require robust scientific understanding and the
development of management systems that will allow negative impacts to
be mitigated and opportunities that arise to be seized.
http:33frdc4com4au3environment3climate_change3f
StephenfMayfield7fSARDI
http:33www4redmap4org4au3
Stephen4Mayfield@sa4gov4au
06_f8f8w/7f54w7
CraigfMundy7fIMASf
Craig4Mundy@utas4edu4au
06_f3f6ww7f7w77
GrettafPecl7fIMAS
Gretta4Pecl@utas4edu4au
06_f3f6ww7f7w77
Photofcredits:f
Antoniaf
Cooper7fElsaf
Gärtner7fRickf
Stuart5Smithff
andfIMAS