Abstract

In response to increased management concerns by the National Marine Fisheries Service in early 1998, we analyzed red snapper (Lutjanidae: Lutjanus campechanus) gonads and otoliths from the U.S. Gulf of Mexico coasts of Texas, Louisiana, Mississippi, Alabama and west Florida (TX, LA, MS, AL and FL respectively). Our main objective related to reproduction was to provide size and age-specific estimates of fecundity (batch fecundity and frequency of spawning) for large red snapper. We previously provided estimates of fecundity (0=66. from 349 to 820 mm total length. TL) from oorth eastern Gulf of Mexico red snapper. However, in order lo complete size/age matrices of spawning frequency, more samples of larger females were needed. We therefore greatly expanded our sampling area and number of samplers. Most samples were provided by headboat samplers stationed from South Padre Island, TX, to St. Petersburg, FL, beginning in late June 1998 and ending in October 1999. Large red snapper (at least 500 mm TL) were non-randomly selected io an attempt lo provide adequate sample numbers of large fish. The sex ratio of all 1517 fish sampled was 1:1. The spawning season off TX and LA began and ended in the same months as in the northeastern Gulf: April - May and September - October, respectively. The presence of hydrated oocytes in ovaries of some large females indicated that spawning began in April 1999 off TX and LA. A few females had hydrated oocytes in October 1998 to signal the end of the spawniog season io all areas. Batch fecundity for 1998 (n = 59. from 359 to 901 mm TL) ranged from an extremely low value of 13 (in a 417 mm TL. 4 year-old TX fish) to an extremely high value of 3.4 million (in a 851 mm TL. 11 year-old LA fish). Both age and TL had an exponential relationship with batch fecundity, but age was the best predictor. Spawning frequency estimates by age (for those ages or age ranges with at least 36 females sampled io 1998) were about 50% greater for age 6-35 females than for ages 3, 4 or 5 females. Several spawning locations around the northern Gulf were also identified using headboat and fishery independeot data along with histology.

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