SEMINAR: MBF 602 Seminar- Veronique Koch February 5th, 2010 4:00pm S/A seminar room

[Cary Rios <crios@rsmas.miami.edu>]

Deep thoughts: black grouper (Mycteroperca bonaci) vertical movements over a coral reef in the upper Florida Keys.

 

 

Black grouper (Mycteroperca bonaci) are one of the most heavily exploited reef fish in the Florida Keys, yet little is known about their movement behavior. Vertical movements have been examined in other species of grouper to determine their spawning seasons, given that serranids are known to make rapid ascents prior to the release of gametes. As part of a larger telemetry study to determine habitat usage, 16 black grouper were tagged using both regular and pressure-sensing (and therefore depth reporting) acoustic tags at Conch Reef and tracked for a year and a half using an array of 19 VR2 self-contained acoustic receivers.  Analyses of depth recordings over time show that the movements of an individual fish are not constant over the course of the year. There is variability in depth recordings with acute changes in temperature gradients. The frequency distributions of depths for three random time periods of equal length show that they are skewed more towards shallow depths in the months of November-February. This period is also when an individual fish will visit a larger number of receivers in the study array. There is also an indication that these ascents occur for short periods of time and primarily during night hours. These isolated behaviors should be considered in management strategies as their increased activity could make them more susceptible to harvesting.

 

Véronique Koch

B.Sc. (Hons) University of Stirling, 2001

Entered MBF Fall 2003

Advised by Dr. David Die

 

Cary Rios 
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Rosenstiel School of Marine & Atmospheric Science

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