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

Crown-of- Thorns ( Acanthaster planci) outbreak in Malapascua island: Monitoring & Control 1

2

COT Population A sse ssm e nt COT density per year • Density of COT increased since 2016 • 10 out of the 15 sites surveyed are experiencing an outbreak of COT • Devastating effects on corals • Threat for the island economy (diving & fisheries) 3

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 12 diameter

Mortality Post - Injection  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 13

Control Methods Comparison Method Cost # COT killed Pros Cons Management tool • Easy • Shallow only Fair Manual • Hard to spot Low participation Good for shallow reef 20- • Cheap COT with big outbreaks removal 40/person • Effective • Injury risk • Reach deep • Fewer COTs Low Injection • Use while fun Moderat Good for deeper reefs • Injury risk 5- e diving or with smaller outbreaks syringe • Scuba 10/syringe guiding • Best numbers • Expensive Good Injection Good for big outbreaks • Reach deep • Equipment High 125- Guns on deep reefs • Easy injection • Dedicated dive 250/gun 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 .