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!