Giant Australian cuttlefish: a globally unique species under threat.

The Environment Institute Where ideas grow Assoc. Prof. Bronwyn Gillanders Giant Australian cuttlefish: a globally unique species under threat?

Bronwyn Gillanders

 Population structure  Melita de Vries  Steve Donnellan  Mike Gardner  PhD/Hons students  Jackie Dupavillon  Nick Payne  Leanne Trott

 Giant Australian cuttlefish & the issues  Population structure  Potential impacts of desalination brine

Weighs up to 13 kg Grows up to 1 m Lives 1-2 years Photo: Kaufmann Productions

Ningaloo Reef Moreton Bay

Adelaide

8 km of coastline Winter – May to August

Rocky reef Habitat map: SA DEH 8 km of coastline Winter – May to August

Males larger than females High male:female sex ratio Males ‘battle’ for females Females may or may not mate with a male Small males have other strategies (e.g. sneakers) Shear numbers impressive Photos: Fred Bavendam

 Skewed towards males (4:1) based on counts of each sex  Assumes individuals on breeding aggregation similar amounts of time  Population sex ratio may be 1:1 with sexes spending different amounts of time on the breeding aggregation  Predict males spend more time than females

Males n = 13 Females n = 6 Payne, PhD project

Residence time Residence period 35 60 Mean Residence Time (days ± SE) Mean Residence Period (days ± SE) 30 50 25 * * 40 20 30 15 20 10 5 10 0 0 Males Females Males Females Male:Female = 3.7 : 1 Male:Female = 4.6 : 1  Population composed of equal numbers of males & females Payne, PhD project

300 270 Renewable moratorium on 240 fishing introduced in 1998 210 Now permanently closed to taking of cuttlefish Catch (tonnes) 180 Need to establish long-term 150 scientific based management plan 120 90 60 30 0 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 From: SARDI Catch Data

 BHP Olympic Dam expansion  Preferred option: coastal desalination plant in USG  Point Lowly preferred location (18 ha site)  Bulk commodities export facility  Feasibility study by Spencer Gulf Port Link Consortium (SGPLC), led by Flinders Ports  7-13 million tonnes of ore could be exported through new facility

 Need to understand population structure for appropriate spatial management  Demographic processes & population dynamics may vary From: Keough & Swearer (2007)

 Strongest inferences use a suite of techniques  Genetic & phenotypic approaches  Might not necessarily expect concordance among approaches  Evolutionary history vs. environmental variation  Spatial resolution varies by technique  Genetic approaches may be more conservative

 Marine populations  Genetic homogeneity over large distances  High dispersal life history characteristics  Squid  High levels of gene flow among populations  Cuttlefish  Sepia officinalis – extensive population structuring

 Determine population structure of giant Australian cuttlefish using a multidisciplinary approach  Molecular (microsatellite DNA markers)  Morphometrics  Statolith chemistry  Investigate spatial & temporal variation in population structure

 Microsatellite genotyping  12 microsatellite loci screened per individual  Kassahn et al. (2006) Marine Biology  Wheaton et al. (2007) Molecular Ecology Notes  Temporal variation  South Australia  Five yrs between 1998 & 2006  Spatial variation  18 sites across Australia

Ningaloo Moreton Bay Breeding 1998 QLD aggregation 2000 2004 WA Whyalla 2005 SA 2006 18 1 NSW 4 5 17 16 3 6 15 2004 2 VIC Wallaroo 2005 14 13 Spencer Gulf Bass Strait GSV Glenelg 1998 1998 Edithburg Aldinga 2005 Cape 2005 Jervis 2005 2006

-20500 Bayesian clustering approach Triplicate runs for 1 (panmixia) to 6 -21500 populations Ln Pr(X | K) Used admixture model -22500 Assumed correlated alleles across populations -23500 Examined each of K populations further to detect sub-population -24500 structure 1 2 3 4 5 6 K, number of populations STRUCTURE

Q Estimated membership coefficients 0.00 0.20 0.40 0.60 0.80 1.00 Whyalla 1998 Whyalla 2000 Whyalla Whyalla 2004 Whyalla 2005 Breeding aggregation Whyalla 2006 Wallaroo 1998 Wallaroo 2005 Wallaroo Spencer Gulf Edithburg 2005 Cape Jervis 2005 Cape Jervis 2006 Shows overall population structure & individual assignment Aldinga/Myponga 1998 Gulf St Vincent Aldinga/Myponga 2005 Length of each line proportional to estimated membership in each group Glenelg 1998 western AUS 1998-2006 Vic WA VIC 2002 NSW 2002/2003 NSW

Q Estimated membership coefficients 0.00 0.20 0.40 0.60 0.80 1.00 Bay Jervis Bay Jervis Jervis Bay Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Wollongong Central & Southern NSW Wollongong Wollongong Wollongong Wollongong Newcastle Newcastle Newcastle Newcastle Newcastle Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Coffs Harbour Northern NSW Coffs Harbour Coffs Harbour Coffs Harbour

 Spatial information – sampling location  1 to 10 populations (n=5 replicate runs)  Fixed K at modal value to estimate assignment of individuals to populations (n=10)  Continued hierarchical analyses to detect subpopulation structure  GENELAND

Population 3 Population 5 Population 1 Population 4 Population 2

South Australia Breeding aggregation Population 5 Contact zone Population 4 100 km

 28 measurements per individual  Removed allometric effects of body size  Sexually dimorphic  sexes analysed separately (n= 173 females & 342 males)  No difference in size among years  pooled years

5 Breeding aggregation GSV & Southern SG 3 Western SA Discriminant function 2 1 90% correctly classified 3 variables used for classification 1 3 variables important: cuttlebone width & 2 beak parameters 3 5 -5 -3 -1 1 3 5 Discriminant function 1 LRL UHL

7 Breeding aggregation GSV & Southern SG Western SA Discriminant function 2 3 90% correctly classified 8 variables used for classification -1 3 beak parameters contribute to differences -5 -5.0 -2.8 -0.6 1.6 3.8 6.0 Discriminant function 1

Dissolved trace Uptake by Statolith elements cephalopod incorporation

Prehatchling Hatchling Sr:Ca statolith (mmol mol-1) Sr:Ca statolith (mmol mol-1) 35 35 Sr:Ca prehatchling statolith (mmol mol ) 30 -1 30 Sr:Ca hatchling statolith (mmol mol ) -1 25 25 20 20 15 15 10 10 5 5 0 0 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 -1 Sr:Ca seawater (mmol mol-1) Sr:Ca prehatchling seawater (mmol mol ) Sr:Ca seawater (mmolmol- ) -1) 1 Sr:Ca hatchling seawater (mmol mol Trott, Hons thesis

5 Breeding aggregation GSV & Southern SG Western SA Discriminant function 2 3 1 Mg:Ca, Sr:Ca & Ba:Ca Discriminant Function Analysis -1 All years – 77% correctly classified 2004 – 78% correct 2005 – 79% correct -3 2006 – 83% correct -5 -7 -3 1 5 Discriminant function 1

 Not one panmictic population  Evidence for 5 populations across species range  Breeding aggregation differs from elsewhere  Evolutionary & ecological implications  Possibly incipient species  Adaptive divergence along an environmental gradient  Recent & rapid differentiation

Ocean again at ~ 7KYA From: Andrew Hugall

 Mating behaviour differs  Physiological tolerance & condition in relation to temperature & salinity ▪ Two populations may be prevented from significant overlap due to differing tolerances  Are individuals from two populations able to mate, are eggs viable, are offspring fertile ▪ Testing degree of reproductive isolation  Determine degree of genetic isolation – genome wide screening  Ecological implications of morphological differences

Intake pipe Proposed locations Breeding area Out take pipe 320 ML SW/day 120 ML FW/day via from USG; 320 km pipeline Salinity >40 ppt 200 ML SW/day returned in more concentrated form; Salinity 78 ppt From: Olympic Dam EIS website

 Discharge of large volumes of highly concentrated brine back to ocean  Elevated salt concentration & contaminants  Elevated temperature & turbidity levels  Decreased oxygen levels  Brine high specific density  sinks to bottom  Could impact adult mating behaviours, & benthic life history stages

 Salinity effects embryonic development  Resources diffuse across membrane  Solubility of gases (e.g. O2) decreased in hyper-saline water  Increased salinity causes a diffusion limitation

n =12 Control Brine 39ppt 40ppt 45ppt 50ppt 55ppt Dupavillon, Hons thesis

Mean field concentration Brine: Increased Sr, Ca, K & Mg High Mg causes mortality and reduced mobility High concentrations found in 45, 50 and 55‰. Treatment - salinity Treatment Dupavillon & Gillanders (2009)

Increase 1‰ = ~7% decrease in survival Total mortality Treatment - salinity Dupavillon & Gillanders (2009)

Smaller size at higher salinity Smaller individuals  less well developed for feeding & swimming Treatment - salinity Dupavillon & Gillanders (2009)

 If brine disperses & background salinity levels reached close to discharge outfall  May be little impact on eggs  But  USG already hypersaline environment  Strong tidal currents, but are USG waters flushed & mixed with ocean waters given bathymetry?  Also, dodge tides  Potential for major impact on GAC

 Mating behaviour highly visual  Inbound migratory routes of cuttlefish  Will adults move up and over high salinity, benthic plumes?  Will adults migrate around benthic plume to reach breeding sites?

 Only known breeding aggregation of cuttlefish in world!  Population at Point Lowly likely a different species  Little if any input from SSG population  Potential for brine to impact early life history stage  Unsure about impacts on adult behaviour & migration  Species can’t move elsewhere to lay eggs  Cephalopods short lived (1-2 years)  No storage effect in population   Need to be more cautious cf. managing finfish

Photos: Fred Bavendam, Sean Connell, Jackie Dupavillon, Kaufman Productions, Nick Payne, Tim Rogers Recent ABC Catalyst story: http://www.abc.net.au/catalyst/stories/2695601.htm

The Environment Institute Where ideas grow Next Seminar: 23 October Assoc. Prof. Veronica Soebarto Environmentally-sensitive design

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Giant Australian cuttlefish: a globally unique species under threat.

by University of Adelaide on Oct 15, 2009

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