how effective are no-take areas on current and historic nassau grouper spawning grounds? p. bush...
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How Effective are No-Take areas on Current and Historic Nassau Grouper Spawning Grounds?
How Effective are No-Take areas on Current and Historic Nassau Grouper Spawning Grounds?
P. Bush
B.X. Semmens, P. Bush, S.A. Heppell, B. Johnson, C. McCoy, C. Pattengill-Semmens, L. Whaylen, S.S. Heppell
B.X. Semmens, P. Bush, S.A. Heppell, B. Johnson, C. McCoy, C. Pattengill-Semmens, L. Whaylen, S.S. Heppell
Nassau Grouper: Conservation Status
• Protected in Bermuda since 1970s
• Protected in Florida since the 1980s
• IUCN Red Listed as endangered
B. Semmens
Spawning Aggregations
• Easy target for fishing
• Few large (functional?) aggregations left
P. Bush
In order to manage spawning aggregations, we need to understand how they work
Study Objectives
• Identify the full geographic and demographic ‘sphere of influence’ of a functional aggregation
• Look for evidence that spawning behavior changes (depensation) after spawning sites have been fished to exhaustion
P. Bush
Cayman Islands
Are the spawning site MPAs warranted?
Sphere of influence of a healthy SPAG?
Evidence for behavioral depensation?
Questions For a Functional Aggregation
• Where are they coming from?
• Do all fish aggregate every year?
• Do older fish aggregate more often?
Study Design• Ring the island of Little Cayman in
hydrophones• Acoustically tag 50 fish
– 30 from the aggregation– 20 from various sites around the island
• Follow them for 2-3 years
Questions For a Functional Aggregation
• Where are they coming from?
• Do all fish aggregate every year?
• Do older fish aggregate more often?
Fish Locations
Blue – Aggregation
Red – Off Aggregation
Questions For a Functional Aggregation
• Where Are They Coming From?
• Do All Fish Aggregate Every Year?
• Do Older Fish Aggregate More Often?
LC Spawning Season 2006
Questions For a Functional Aggregation
• Where are they coming from?
• Do all fish aggregate every year?
• Do older fish aggregate more often?
Big, Old Fish• Bigger fish showed up earlier and stayed
longer
B. Semmens
Questions For a Remnant Aggregation
• Do fish migrate to spawn?
• Can fish find the spawning site?
• If they find the spawning site, do they spawn?
Questions For a Remnant Aggregation
• Do fish migrate to spawn?
• Can fish find the spawning site?
• If they find the spawning site, do they spawn?
Brac Spawning Season 2007
Questions For a Remnant Aggregation
• Do fish migrate to spawn?
• Can fish find the spawning site?
• If they find the spawning site, do they spawn?
Do Remnant Aggregations Spawn?
• BIG NEWS: Spawning observed on all three islands in 2009!!
Management Implications?• Preserving local spawning sites
preserves local spawning stocks (in entirety!)
• Protecting spawning sites even after exhaustive fishing is a really good idea
• Given the excessive use of ‘corridors’, conservation of this species may require more than just SPAG site MPAs
P. Bush
Support Provided ByCI Businesses:
Little Cayman Beach Resort
Head of Bay
Pete Hillenbrand
McCoy’s Dive and Fishing Lodge
Pirate’s Point
Southern Cross Club
REEF Volunteers
Funding:
Pew Lenfest Ocean Program
NOAA International Coral Reef Conservation Fund
PADI Project Aware
J. Edward Mahoney Foundation
REEF
CIDOE
Oregon State University
Hey Baby!