A sample of red snapper discards was collected at each site during both open and closed seasons. These fish were systematically and randomly sampled through retention of every nth fish, depending on catch rate, such that approximately 20 discarded red snapper were sampled on each trip.
Differences in the species composition of the catch and discards for open and closed seasons were tested with permutational multivariate analysis of variance (PERMANOVA) in Primer 6 (PRIMER-E Ltd, Ivybridge, UK) with PERMANOVA+ (Anderson et al., 2008).
Observers collected data on 24 charter boat trips in 2012 and on 30 trips in 2013; 32 trips occurred during red snapper open seasons and 22 trips occurred during closed seasons. Differences between open and closed seasons were observed for several parameters of effort (Fig.
During red snapper closed seasons, fishermen predominantly used rig type II to target smaller reef fishes (e.g., vermilion snapper [Rhomboplites aurorubens], red porgy [Pagrus pagrus], or gray triggerfish [Batistes capriscus]).
The species composition of the catch from charter boat trips was significantly different between red snapper open and closed seasons (PERMANOVA, pseudo-[F.sub.1;53]=21.46, P<0.001; Table 1).
For example, all gag (Mycteroperca microlepis) observed during this study were caught during closed seasons and were, therefore, discarded.
During closed seasons, captains fished more frequently on natural reefs that, by comparison, had higher species diversity and lower red snapper abundances than those at the artificial reefs during open seasons, (Dance et al., 2011; Patterson et al., 2014).
In our study, red snapper catch was 61% lower during closed seasons than during open seasons, but discards declined by only 23% and were not significantly lower during closed seasons.
Several reasons exist for the difference between this study and that of Schirripa and Legault (6) in the reported change in the number of red snapper discards for open and closed seasons. First, red snapper abundance has increased in the northern GOM since the late 1990s; therefore, more fish are available to be caught now (SEDAR5).
Catch rates for species other than red snapper were generally low, and overfished species (i.e., gag, gray triggerfish, and greater amberjack) were discarded because of either minimum length limits or closed seasons. High discard mortality of physoclistous fishes caught in deep waters (depths >40 m), combined with intense gulf-wide recreational fishing effort (Coleman et al., 2004; Hanson and Sauls, 2011), likely amplifies the impact of discarding practices during closed-season trips given the greater depths fished compared to open-season trips (Wilson and Burns, 1996; Coggins et al., 2007; Rummer, 2007; Campbell et al., 2014).