NOAA CORAL REEF GRANT PROGRAM PROJECTS TO IMPROVE OR AMEND CORAL REEF FMPs NA08NMF4410463 Validation of a Spawning Aggregation of Mutton Snapper and Characterization of the Benthic Habitats and Fish in the Mutton Snapper Seasonal Closed Area, St. Croix, U.S. Virgin Islands Submitted to: Caribbean Fishery Management Council San Juan, Puerto Rico Barbara L. Kojis and Norman J. Quinn Date: 15 February 2011 i Table of Contents List of Tables ................................................................................................................................. iii List of Figures ................................................................................................................................. v EXECUTIVE SUMMARY ............................................................................................................ 1 CHAPTER 1 ................................................................................................................................... 4 Mutton Snapper (Lutjanus analis) Spawning Aggregation in the Mutton Snapper Seasonal Closed Area, St. Croix, U.S. Virgin Islands ................................................................................... 4 INTRODUCTION ...................................................................................................................... 4 MATERIALS AND METHODS ................................................................................................ 9 Fishing Dates and Methods ..................................................................................................... 9 Scuba Diving Searches for Lutjanus analis .......................................................................... 11 Fish Abundance Assessment by Fishing Effort .................................................................... 12 Biometric Analysis................................................................................................................ 12 Sex Determination ................................................................................................................ 13 Fecundity and Oocyte Size Distribution ............................................................................... 13 Otoliths, Diet, and Genetic Samples ..................................................................................... 14 RESULTS ................................................................................................................................. 16 Catch Results in the Mutton Snapper Seasonal Closed Area ............................................... 16 Reproductive Aspects ........................................................................................................... 21 Length Weight Relationship ................................................................................................. 25 Fecundity and Egg Size Distribution .................................................................................... 26 DISCUSSION ........................................................................................................................... 30 Spawning Season .................................................................................................................. 30 Spawning Aggregation Location .......................................................................................... 32 Status of the Mutton Snapper Aggregation ........................................................................... 33 Size at Onset of Reproduction .............................................................................................. 34 Maximum Length and Age ................................................................................................... 35 Sex Ratio ............................................................................................................................... 36 Fecundity............................................................................................................................... 36 Conclusions ........................................................................................................................... 37 LITERATURE CITED - CHAPTER 1..................................................................................... 39 APPENDIX 1 ............................................................................................................................ 44 CHAPTER 2 ................................................................................................................................ 45 Habitat Description of the St. Croix, U.S. Virgin Islands Mutton Snapper Seasonal .............. 45 INTRODUCTION .................................................................................................................... 45 METHODS - BENTHIC SURVEY.......................................................................................... 52 RESULTS – BENTHIC SURVEY ........................................................................................... 53 i Prada (2003) Habitat Type - Submerged Aquatic Vegetation on Unconsolidated Sediments ............................................................................................................................................... 54 Prada (2003) Habitat Type - Bare or Mixed Invertebrate on Unconsolidated Sediments .... 61 Coral and Gorgonians on Consolidated Sediments .............................................................. 65 DISCUSSION - BENTHIC SURVEY ..................................................................................... 76 WATER TEMPERATURE ON ST. CROIX ........................................................................... 78 INTRODUCTION .................................................................................................................... 78 MATERIALS AND METHODS - TEMPERATURE ............................................................. 78 RESULTS - TEMPERATURE ................................................................................................. 78 DISCUSSION - TEMPERATURE........................................................................................... 80 LITERATURE CITED - CHAPTER 2..................................................................................... 81 APPENDICIES CHAPTER 2 ....................................................................................................... 83 Appendix 1 - Abstract 63rd Gulf and Caribbean Fisheries Institute Meeting ............................... 84 Appendix 2 - Summary of Benthic Habitat Analysis: Benthic Categories ................................... 85 Appendix 3 - Summary of Benthic Habitat Analysis: Coral Species ........................................... 94 CHAPTER 3 ................................................................................................................................. 99 Habitat Focused Fish Surveys in the Mutton Snapper Seasonal Closed Area ............................. 99 INTRODUCTION .................................................................................................................... 99 MATERIALS AND METHODS ............................................................................................ 100 Fish and Caribbean Spiny Lobster and Queen Conch Transects ........................................ 100 Roving Fish Censuses ......................................................................................................... 101 Fish Biodiversity ................................................................................................................. 101 RESULTS ............................................................................................................................... 102 Habitat Overview ................................................................................................................ 103 Habitat Summaries .............................................................................................................. 104 Population Abundance of Marketable Fish......................................................................... 109 DISCUSSION ......................................................................................................................... 114 Commercially Harvested Fish Recorded in the MSSCA .................................................... 114 LITERATURE CITED ........................................................................................................... 119 APPENDICIES - CHAPTER 3 .................................................................................................. 121 Appendix 1: List of Presence / Absence of Fish Species by Habitat ...................................... 122 Appendix 2: Benthic Transect Fish Abundance by Habitat ................................................... 134 Appendix 3 - Queen conch (Strombus gigas) Distribution and Abundance in MSSCA Habitats ................................................................................................................................................. 166 Appendix 4 - Abstract 63rd Gulf and Caribbean Fisheries Institute Meeting ......................... 169 CHAPTER 4 ............................................................................................................................... 170 Pilot Study of Back Reef Embayments and Bays on the East End of St. Croix as post settlement habitat for juvenile grouper and snapper .................................................................................... 170 INTRODUCTION .................................................................................................................