Abstract

The red hind is the most important commercial grouper in Puerto Rico (Matos-Caraballo 2002) and is characterized by the formation of spawning aggregations at known sites and times (Nemeth et al. 2007, Shapiro et al. 1993, Sadovy et al. 1994). This behavior make the species highly vulnerable because fishers can target the aggregations, bringing intense fishing effort over a small area; as a consequence several aggregations are known to have collapsed or suffered large decreases in abundance (Beets and Friedlander 1999, Marshak and Appeldoorn 2008). This same behavior, however, offers the unique possibility of easily assessing the status of the spawning stock, if the aggregation locations are known. Quantita-tive surveys of spawning stock offer the potential to directly assess stock health and monitor stock decline/recovery (Beets and Friedlander 1999, Nemeth 2005). However, such surveys need to be timed to the occurrence of fish at the sites, and they are subject to understanding the factors driving aggregation behavior. Passive acoustic monitoring of species-specific courtship associated sounds (CASs) is a convenient way of determining the temporal pattern of reproductive activities, as call counts and sound levels are related to the abundance of fish within a specific aggregation (Appeldoorn et al. 2013, Mann et al. 2010, Rowell et al. 2012). We used passive acoustic monitoring of red hind CASs to determine the temporal patterns of aggregation formation at Abrir la Sierra (ALS) over multiple years and for single years at two additional sites off the west coast of Puerto Rico. The purpose of this study was to study the variations in the temporal dynamics of red hind spawning across space and time, with the goal of developing a better predictive capacity for when red hind aggregate and potentially understanding what may drive observed differences.

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