Seasonal Relationships of Caloric Content and Liver Weight In Red Snapper On Natural Hard- Bottom Banks in the Northwestern Gulf of Mexico

We are conducting a study on red snapper Lutjanus campechanus to gather more information about their life history and behavior on the Louisiana (LA) continental shelf banks. Red snapper are collected twice per quarter from four banks on the LA shelf, including Jakkula, McGrail, Bright, and East Cameron Artificial Reef Planning Area.  Sampling began September 2011 and will continue through October 2013.  The liver-somatic-index (LSI) was calculated by dividing the liver weight by the eviscerated body weight.  Caloric content of fish tissue was estimated directly by a Parr 6200 oxygen bomb calorimeter.  Results indicate seasonal patterns in both the LSI and caloric content.  LSI increased from September 2011 to March 2012, peaked in May 2012, and then declined with a low in October 2012.  The caloric content was lowest in September 2011, increased and peaked in May 2012, and then decreased in July 2012.  Red snapper appear to be using energy stores from both the liver and tissue towards reproduction.  Energy and fat reserves began accumulating from September 2011 to May 2012, with May being the start of the spawning season.  The fat and energy stores were then depleted during spawning, resulting in the decrease in the LSI and caloric content.