the institute for marine and antarctic studies · institute for marine and antarctic studies 28...

The Institute for Marine and Antarctic Studies

Restocking Southern Rock

Lobster with juveniles ongrown from wild-caught

puerulus

Caleb Gardner

INSTITUTE FOR MARINE AND ANTARCTIC STUDIES 2

Scallop farming commenced in Tasmania in the late 1980s

Tasmania

1996: State Government Department for Primary Industries sent

some graduate recruits to visit the farms….and they returned

excited with a bucket full of juvenile lobsters – “bycatch” from the

scallop equipment.






scallop equipment.

1997: The idea of collecting and growing juvenile lobsters was born.

Later trips confirmed there were indeed 1000s of puerulus (and

galathids)


Southern Rock Lobster - Background

Harvested in Southern Australia and New Zealand

Harvesting for food and trade by Aborigines (~ 40,000 years) and

Maori (~1000 years)

Many recreational fishers (eg 20,000 in Tasmania alone)

High value commercial fishery – fishers receive AUD$100/kg (=

~USD$70/kg, or USD$ 32/ pound)


Southern Rock Lobster - Background

The price is high because catch (ie supply) is constrained.

1. All commercial harvest limited by individual transferable quotas

(ITQs or catch shares)

2. No aquaculture production because the larval duration is long (~ 18

months)


1996 to 1998…..

Tasmanian government had previous success with new industries of

salmon and oyster farming

Initiated research on aquaculture of many other species ….including

rock lobster.


1996 to 1998…..

Green mussel farmers in New Zealand were getting puerulus

bycatch and lobbied to be allowed to keep and grow them.

Introduced commercial puerulus harvest (commercial lobster fishery

were not supportive!).

Interest from other parts of Australia: Western Australia, Queensland

National research program created for “Rock Lobster Enhancement

and Aquaculture Subprogram “RLEAS” (of FRDC) created.


Survival 1 year post-settlement known to be low

Typically > 100 puerulus p.a. on collectors…yet few juveniles on reef


Taking puerulus shouldn’t harm the wild fishery because 1 year post-settlement known to be low

1. Puerulus harvest trials in WA (Phillips and Smith)

- showed catches in grid had only slight edge or attractant effect.

- estimated natural mortality in year 1 at ~ 100%

2. Natural mortality estimates of P. argus in Florida

(Butler et al.) also ~ 100%.

3. Field trials on artificial reef formed with brocks at Bicheno in ~2005 also

had mortality in Y1 ~ 100%


Exploratory commercialisation

1. 1999. Tasmanian government invited applications for permits to harvest

puerulus and ongrow.

2. Three permits issued: Oyster Farmer consortium, A salmon company, and a

“mixed” seafood business.

3. Opposed by commercial RL fishers because (i) competition, (ii) disease risk,

and (iii) undermined their exclusive private ownership of the resource

“property right”.

4. If they captured 10,000 puerulus, they were required to release 20% (2,000)

as 1 y.o. juveniles to provide fishery enhancement, and “compensate the

ecosystem”.


Three years later…failure. Why?

1. The national research sub-program was dominated by researchers

wanting to dismiss puerulus harvest and capture $ for hatchery

production

2. The salmon farming company lost interest because their company

almost collapsed from incompetent management…so they needed to

focus on salmon

3. Government requirement to release 1 year juveniles = 20% of N

puerulus harvested made operations unprofitable.

4. Pueurlus harvest permits were used to enable criminal poaching.

Transferring ownership of undersize lobsters from public to private

ownership doesn’t work.


Almost 20 years later, why am I still discussing this?


Almost 20 years later, why am I still discussing this?

Because we’re just starting up again…


Shellfish farmers still keep catching 100,000s of puerulus every year ..that all die


More puerulus than urchins in these cages….and they’re all wasted.

Viable lobster culture operations elsewhere that pay USD$12 / puerulus


Viable lobster culture operations elsewhere that pay USD$12 / puerulus


We know lobsters can be

grown and sold if we have

access to puerulus…

A new approach to avoid conflict…


Puerulus

collected

from marine

farms

(oysters,

salmon)

Transported

to

government

tank facility

Ongrown

for 12

months

Released

back into

wild

Advantages: overcomes policy issues – fully public, no

privatisation of undersize lobsters. No conflict this time!

Issues: how much $ do we need to pay oyster farmers to

carefully collect puerulus? costs for ongrowing and

enhancement? Research to refine husbandry. And who

pays?

IMAS, UNIVERSITY OF TASMANIA

Potential sources of funding for enhancement..

1. Recreational licence fee. Daily bag limits have been cut from

5 to 2 in the past 3 years..and may go to 1. We could restore

these stocks with recreational licence fees…



2. Commercial licence levy (they already contribute $100K p.a.

to enhance the fishery with translocation)


Potential sources of funding for enhancement

3. Offsets for oil, gas, and wind farming impacts – already

compensating for opportunity cost to commercial fishers


Potential sources of funding for enhancement

4. Government – they’re already funding enhancement by

translocation of lobsters to increase predation of urchins



5. Special, high-density, permit zones for tourism. Eg Flinders

Island: low natural settlement, high growth, reputation for

premium food, complex Aboriginal heritage

Foundation of historic research

1. Survey of locations and probable numbers from aquaculture

2. Designs for collectors to catch peurulus at commercial scale

3. Economic analysis of enhancement / puerulus harvest combo.

4. Tank design, grow-out, density, feed experiments

5. Health assurance testing before release

6. CJS Mark-recapture designs and experiments for assessing post-release

survival

7. Behavioral responses to predators and training for natural behavior

8. Release methodology

9. Ecosystem characterizing for selecting high-survival release sites

10.Post release dispersal.

11.Successful pilot scale releases of ~ 2000 juveniles.


Research foundation


Some of the 1Y juveniles

grown and released in

previous trials in Tas

Tank systems in NZ Tank systems in Tas.

Experiments on density,

shelter systems. Also feed

experiments such as prawn

pellets.

Measuring growth in

rearing experiments

Old fashioned acoustic

tracking of dispersal.

Relocation of acoustically

tagged released juveniles

by divers (every 4 hours

through the night in winter!)

then measuring distance by

tape.


Some puerulus

salvaged from a

shellfish farm and

the drums used for

transport.

If we offered an

oyster farmer $1 /

puerulus, would

they participate?

These were picked off the deck of

a barge doing a salmon net

change.

Measuring

survival in

the 30 to

75mm gap.

Field experiments on

improving post-release

survival. That’s an IR

camera system.

Research foundation

Research


Some oyster systems are good at

catching puerulus. Industry were

surveyed on this 20 years ago.

Great catches sometimes although

it is inconsistent.

We’re also using oyster baskets for

monitoring puerulus (filled with mesh,

not oysters).

Excellent design although onion bags

cheaper and OK for short

deployments during peak settlement.

Require 1 month conditioning.

Research


Behavioural

experiments with

naive lobsters in NZ

(notice they’re not

sheltering in the day)

Tethering experiments to

measure relative predation risk of

habitat types.

Antennae of

puerulus in

experiment

to measure

natural

mortality.

Ongrown juveniles

tend to go bright pink.

Diet experiments

showed their colour

could be changed to

more natural with

astaxanthin.

Research


Coloured beads on

antennae to

individually tag

released juveniles for

measuring survival

and dispersal.

Some cannibalism of

released juveniles.

Artificial reef

used for

measuring

puerulus

natural

mortality.

Research


Behavioural

experiments with

naive lobsters in NZ

(notice they’re not

sheltering in the day)

Low cost efficient collector experiments.

Research Challenges

- Efficient collection, holding and transport of puerulus from farms to

growout facility

- Pilot testing the payment system to incentivise farmers to collect

puerulus

- Refining growout (nutrition, tank design etc)

- Building the business case for ongoing operations


Research Challenges

Diet and husbandry research underway for commercial tropical lobster

aquaculture (hatchery produced puerulus)


Thank you


(PS I need to travel up to Tampa Friday

morning. Is anyone else? Want to share

the trip up?)

the institute for marine and antarctic studies · institute for marine and antarctic studies 28...

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