Table 1. Von Bertalanffy growth parameters and length-weight relations for red snapper

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Red snapper,

Lutjanus campechanus (Poey, 1860)

Red snapper are distributed throughout the Gulf of Mexico and up the U.S. Atlantic coast to North Carolina and, although rarely, to Massachusetts. Gold et al. (1997), Camper et al.

(1993), and Heist and Gold (2000) provide genetic evidence that support the hypothesis of a single red snapper stock in the northern Gulf of Mexico. It is possible that spatially separated sub-populations of red snapper in the gulf may not have had sufficient time since the Pleistocene epoch to have become genetically distinct, or that there is enough mixing to maintain

homogeneity in the population. Spawning, which occurs from April through January, peaks in June and July over most of its range (Bradley and Bryan 1975). Red snapper appear to move away from reef structure when spawning. Wilson et al. (1994, cited by Goodyear 1995b) found that red snapper first matured between 10.2 inches and 13.8 inches total length (TL); of the fish in their sample, 50% matured by 11.8 inches. Goodyear (1995b) analyzed data from several sources and found little evidence for strong sexual dimorphism. Early growth of red snapper appears to be similar for both otolith-determined ages and scale-determined ages. Sizes at age were about 5.7–6.9 inches TL at age 1, 10.5–11.7 inches at age 2, reaching about 27.0 inches by age 7 (Nelson and Manooch 1982). An analysis of otolith-section-based ages gave smaller sizes at age after age 2 in the U.S. South Atlantic waters (Table 1; Manooch and Potts 1997c). Mean back-calculated total lengths for combined sexes were 6.8” TL, 10.2” TL, 13.6” TL, 16.4” TL, 19.3” TL, 21.9” TL, and 23.7” TL for ages 1–7. Maximum ages for Gulf of Mexico red snapper differed substantially between the two aging techniques: scale-determined maximum ages were about 16 years; whereas, the maximum otolith-determined age was 54 years (Wilson and Nieland 1997). Similarly, a recent study in the south Atlantic found that otolith methods using both observed lengths with fractional age and back-calculated lengths to the last annulus resulted in a maximum age of 54 years (Table 1; McInerny 2007).

Table 1. Von Bertalanffy growth parameters and length-weight relations for red snapper Inches TL = L∞ (1-e^-K(age-t0)) K L∞ (inches TL) t0 (years) Source

Sex combined, southeastern U.S. 0.146 37.5 0.182 Manooch and Potts (1997c) Sex combined, Gulf of Mexico 0.17 37.0 -0.1 Nelson and Manooch (1982) Sex combined, south Atlantic 0.25 35.3 0.16 McInerny (2007)

Weight in lbs = a (inches TL)^b a b Source

Sex combined, southeastern U.S. 0.000525 2.99 Manooch and Potts (1997c) Sex combined, Gulf of Mexico 0.000589 2.97 Nelson and Manooch (1982) Sex combined, south Atlantic 0.000510 3.05 McInerny (2007)

The types of prey that contributed the greatest percentage by volume to the diet of juvenile red snappers were squid, octopuses, and shrimp (Bradley and Bryan 1975). Camber (1955) stated that the gulf red snapper prey primarily on shrimp, small reef fish, crabs, and gastropods. The following fish species were among those most often found in the red snapper diet: gulf pipefish, shoal flounder, puffer family, striped mullet, sea robin family, rough scad, butterfish family, sand perch, and clupeids. Juvenile red snapper habitat is characterized by 18-

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m–64-m deep water, 24 °C–26 °C water temperatures, 35 ppt salinities, and at least 5 mg/L of dissolved oxygen (Gallaway et al. 1999). Experiments on captive 2–4 inch standard-length juvenile red snapper found a preference for shell substrate over sand substrate (Szedlmayer and Howe 1997).

Total annual landings of red snapper in Florida during 2013 were 6,251,096 pounds. The commercial landings accounted for 35% of the total landings. Nearly 96% of the total landings were made on the gulf coast. Counties with the highest reported commercial landings on the Florida gulf coast were Escambia, Okaloosa, Bay, Franklin, and Pinellas (Fig. 1a). Recreational landings of red snapper were greatest in the Panhandle (northwest) region (Fig. 1b). The 2013 total landings of red snapper were 88% higher than the average landings in the previous five years (2008-2012) and were 129% higher than the 1982–2012 historical average landings (Fig.

2). On the Atlantic coast, total annual landings of red snapper were less than 170,000 pounds between 1995 and 1999; total landings increased to about 510,000 pounds in 2000 then showed a decreasing trend through 2005 and have increased through 2009 until commercial landings were ceased in 2010-2011. In partial reflection of more restrictive regulations on both the commercial and recreational fisheries, gulf coast landings began to decline in the early 1980s (Fig. 2). The increase observed since 1996 may be an expansion of the range of red snapper into the eastern gulf as its abundance increases in the northern gulf (Schirripa and Legault 1999).

Standardized commercial landings rates have generally increased since at least 1992 on the Atlantic coast until 2009, and show recent drops in 2010-2011 due to regulations (Fig. 3a).

On the gulf coast, landings rates have increased more dramatically from 1996-2002, slowly declined through 2005, and have increased again in 2006-2013 (Figs. 3b). The total catch rates for the Atlantic coast recreational fishery appear to have declined slightly through the late 1990s, increased through 2007, then followed by a recent decline in 2008-2011 (Fig. 3c). Gulf coast recreational catch rates were stable from 1991-1995, displayed steep increases from 1996-1999, remained high and fluctuated through 2007, and have recently shown decreases through 2013 (Fig. 3d).

Red snapper support a premier foodfish fishery in the Gulf of Mexico. The fishery developed in Pensacola about 150 years ago (Bortone et al. 1997), and then, after the resource became scarce in waters near Pensacola, the fishery expanded to the waters off Galveston, Texas, the Campeche Banks, and the Dry Tortugas during the late 1800s (Goodyear 1995b).

Under Section 303 of the Magnuson-Stevens Act, regional fishery management councils are charged with assessing the condition of their stocks; Technical Guidelines (Restrepo et al.

1998) set forth procedures for identifying biomass-based measures such as Maximum Sustainable Yield (MSY), the Maximum Fishing Mortality Threshold (MFMT) and the Minimum Spawning Stock Threshold (MSST). Along the U.S. South Atlantic coast, the red snapper stock was judged in a “transitional” stage (Manooch et al. 1998) during the period 1992–

1995; static SPRs ranged from 0.11 to 0.32. These authors pointed out the need to increase minimum size limits or reduce fishing mortality to bring this species into compliance. The South Atlantic Fishery Management Council’s Snapper-Grouper Assessment Group supported the findings that the spawning biomass of red snapper was well below the spawning stock at MSY (B2003/BMSY = 0.29) in 2003.

The benchmark assessment of South Atlantic red snapper concluded that the stock is overfished and is undergoing overfishing (SEDAR 15 2008a). The spawning biomass has decreased further below the spawning stock at MSY (B2006/BMSY = 0.025) and overfishing has been occurring through 2006 (SEDAR 15 2008a). In addition, the 2006 level of fishing

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mortality (F) was greater than seven times that at FMSY (F2006 / FMSY = 7.513). Moreover, the base model estimates from the most recent stock assessment indicate that the U.S. southeast stock of red snapper was overfished and was undergoing overfishing in 2009 (SEDAR 24 2010).

Stock status in 2009 was estimated to be SSB2009/MSST = 0.09 and fishing mortality was

estimated to be F2007-2009/FMSY = 4.12. Age structure estimated by the base run shows fewer older fish than the age structure expected at MSY (SEDAR 24 2010). To implement long-term

management measures to end overfishing of the red snapper Atlantic stock, total prohibition of south Atlantic red snapper harvest began in December 2010 (SAFMC 2010).

Past assessments conducted for the Gulf of Mexico stock, with regard to common

biology-based benchmarks to overfishing, have concluded that red snapper in the Gulf of Mexico were grossly overfished through 2003 (Goodyear 1995b, Schirripa and Legault 1997, 1999, SEDAR 07 2005). In general, estimates of spawning potential ratio (SPR) were less than 5%

(Goodyear 1995, Schirripa and Legault 1999, SEDAR 07 2005). The most recent stock assessment for the Gulf of Mexico Red Snapper stock used the Stock Synthesis (SS3) model (SEDAR 31 2013). The review panel determined it could neither accept nor reject the assessment findings and could not determine stock status in relation to reference points due to the absence of an acceptable quantitative stock assessment. However, results suggest the Gulf of Mexico red snapper stock remains overfished according to the base model and all of the sensitivity models examined, except a sensitivity model using a high natural mortality rate for age-0 and age-1 individuals. Model results also suggest that overfishing is not occurring according to the base model and all of the sensitivity models examined.

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a. Commercial landings (pounds) b. Recreational landings (numbers)

Figure 1 (a)-(b). Geographic distribution of red snapper landed during 2013. (a) Commercial landings (pounds) by county; (b) Recreational landings (numbers of fish) by region.

Figure 2. Total annual landings (pounds) of red snapper on the Atlantic and gulf coasts of Florida, 1982–2013.

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a. Atlantic Coast, commercial landings rates (pounds/trip) b. Gulf Coast, commercial landings rates (pounds/trip)

c. Atlantic Coast, recreational total catch rates (numbers/trip) d. Gulf Coast, recreational total catch rates (numbers/trip)

Figure 3 (a)-(d). Annual standardized catch rates for red snapper in Florida. Commercial landings rates (pounds/trip), 1992-2013: (a) Atlantic Coast; (b) Gulf Coast. Recreational total catch rates (numbers/trip), 1991-2013: (c) Atlantic Coast; (d) Gulf Coast.

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