Crown-of- Thorns ( Acanthaster planci) outbreak in Malapascua - - PowerPoint PPT Presentation

Crown-of- Thorns

(Acanthaster planci) outbreak in Malapascua island: Monitoring & Control

1

2

• Density of COT

increased since 2016

• 10 out of the 15 sites

surveyed are experiencing an

• utbreak of COT
• Devastating effects on

corals

• Threat for the island

economy (diving & fisheries)

COT Population A sse ssm e nt

3

COT density per year

Two Rocks July 2019

4

5

COT M onitoring & Control

WHY MONITORING ?

• Early detection of outbreaks
• Assess efficiency of control program

COT CONTROL METHODS:

• Manual removals
• Vinegar injections

6

Avoid Stress Spawning

 When disturbed COTs can release theirs eggs  Remove COTs from the water as quickly as

possible, and place them in the boat.

 Prevent re-immersion of collected COTs  Save water from basins and dispose on land  GreenFins guidelines : bags/boxes of COTs have to

be brought back to the surface BEFORE

15min Max

7

8

Freediving Manual Removals

 Working in buddy pairs  Each pair has basin + tongs  Be careful to not break corals! – Peel off  Be careful to not break COTs – Don’t stab or rip

hard to reach COTs

 Bring COTs immediately to surface and in basin  Be careful to not spill basin  Be careful of sting !

9

Scuba and Vinegar Injections

 Injection of 20 mL household vinegar  200mL syringe with 16 gauge needle  Several full syringes can be carried by divers in

sheath

 Be VERY careful of stings !  5-10 COT injected / syringe  Way to fill the syringes underwater?  Use a sponge as buffer

10

Scuba and Vinegar Injections

 Injection guns – AMPTO  Less prone to injuries and stress spawning  5 L Bottle & Hose : 125-250 COTs injected  AUD$160 (6,000PHP) / gun + shipping  Initial investment

BUT can remove many more COTs and easier

11

Scuba and Vinegar Injections

 Working in buddy pairs with one injector  One person injects, one person records and

spots

 Use hook to peel off COT if needed  Be careful to not rip COT  Inject 20mL of vinegar at the base of the arm  Do not push all the way through  Use food dye to see vinegar  2 injections on opposite sides for COTs > 40cm

diameter

12

 2 hours start to contract  10 hours completely immobile  Within 24 hours DEAD  Reef fish will clean up the

remains

⚠︐ Too many injected COTs

can create nutrient overload

Mortality Post - Injection

13

Control Methods Comparison

Method Cost # COT killed Pros Cons Management tool

Manual removal

Low Fair 20- 40/person

• Easy

participation

• Cheap
• Effective
• Shallow only
• Hard to spot

COT

• Injury risk

Good for shallow reef with big outbreaks

Injection syringe

Moderat e Low 5- 10/syringe

• Reach deep
• Use while fun

diving or guiding

• Fewer COTs
• Injury risk
• Scuba

Good for deeper reefs with smaller outbreaks

Injection Guns

High Good 125- 250/gun

• Best numbers
• Reach deep
• Easy injection
• Expensive
• Equipment
• Dedicated dive

Good for big outbreaks

• n deep reefs

14

15

Data to Colle ct

MONITORING

• Record location of outbreaks
• Monitor sites after eradication program

ERADICATION

• GPS coordinates of the sites
• Number of COT collected/injected
• Number of participant
• Duration of the removal/injection session
• Depth
• If possible: diameter of COT, predated corals

16

Useful Inform ation

• Great Barrier Reef Marine Park Authority Report.
• 2017. Crown-of-thorns starfish control guidelines:

second edition.

• DENR Technical Bulletin

2017-13. Guidelines on the implementation of Environmental standards for diving and snorkeling.

• Green Fins Crown of Thorns

Cleanup Guidelines.