Gulf of Mexico Science Volume 25 Article 3 Number 1 Number 1 2007 Recruitment and Essential Habitat of Juvenile Sand Seatrout (Cynoscion arenarius) in Four Estuaries Along the West Coast of Florida Caleb H. Purtlebaugh Florida Fish and Wildlife Conservation Commission Kristin R. Rogers Florida Fish and Wildlife Conservation Commission DOI: 10.18785/goms.2501.03 Follow this and additional works at: https://aquila.usm.edu/goms Recommended Citation Purtlebaugh, C. H. and K. R. Rogers. 2007. Recruitment and Essential Habitat of Juvenile Sand Seatrout (Cynoscion arenarius) in Four Estuaries Along the West Coast of Florida. Gulf of Mexico Science 25 (1). Retrieved from https://aquila.usm.edu/goms/vol25/iss1/3 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf of Mexico Science by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. Purtlebaugh and Rogers: Recruitment and Essential Habitat of Juvenile Sand Seatrout (Cyno Gulf of Mexico Science, 2007(1), pp. 15-32 Recruitment and Essential Habitat of Juvenile Sand Seatrout ( Cynoscion arenarius) in Four Estuaries Along the West Coast of Florida CALEB H. PuRTLEBAUGH AND KmsnN R. RoGERS The sand seatrout (Cynosciou m·marillS) is an ecologically and economically important species common to estuarine and nearshore waters of the Gulf of Mexico. Currently, comprehensive information on the essential habitat of juvenile sand seatrout is limited. We analyzed data from a long-term fisheries-independent monitoring program to assess the spatial and temporal distributions of juvenile sand seatrout relative to various habitat parameters in four estuaries (Apalachicola Bay, the Suwannee River estuary, Tampa Bay, and Charlotte Harbor) along the gulf coast of Florida. A total of 25,668 sand seatrout (oS100 mm SL) were collected during monthly stratified-random sampling from Jan. 1996 through Dec. 1997 and Jan. 2001 through Dec. 2003. Specimens were collected with 21.3-m bag seines and 6.1-m otter trawls; the majority of specimens were captured in trawls from water ~ 1.8 m deep. Juvenile sand seatrout primarily recruited into the estuaries from May through Oct., although recruitment began 1 mo earlier in Tampa Bay. Juveniles were most abundant over unvegetated mud bottoms, in mesohaline salinities, and near salt marsh vegetation. Highest abundances also occurred in small rivers, tidal creeks, and areas adjacent to the mouths of large rivers. Juveniles between 30 mm SL and 70 mm SL primarily occupied mesohaline salinities before shifting toward higher salinities as they approached 100 mm SL. INTRODUCTION estuaries (Christmas and Waller, 1973; Warren and Sutter, 1982). Information on relative and seatrout ( Cynoscion arenarius) are one of abundance and habitat associations of sand S the most common sciaenid fishes within seatrout is limited and in most cases has been estuaries of the northern Gulf of Mexico ancillary to larger studies (Gunter, 1938; Christ­ (Rakocinski eta!., 2002). Although sand seatrout mas and Waller, 1973; Gallaway and Strawn, have historically been thought to range westward 1974; Chittenden and McEachran, 1976; Warren along the gulf coast from southwest Florida to and Sutter, 1982). The majority of studies on the Gulf of Campeche, Mexico (Moffet et a!., sand seatrout have been principally from the 1979), recent genetic analyses indicate that they northwestern gulf (Texas, Louisiana, and Mis­ also occur commonly throughout inshore waters sissippi) (Gunter, 1945; Christmas and Waller, of Florida's Atlantic coast (Tringali eta!., 2004). 1973; Gallaway and Strawn, 1974; Cowan and Sand seatrout support a substantial recreational Shaw, 1988), with only one study conducted on and commercial fishery along the gulf coast of juvenile sand seatrout along the gulf coast of Florida. From 2001 to 2003, annual recreational Florida (Peebles, 1987). landings from the gulf coast of Florida averaged In our study, we used a stratified-random 230 metric tons (mt) [approximately 1 million sampling design with standardized protocols to fish year (National Marine Fisheries Service, sample and estimate the relative abundance of 2004)], and commercial landings averaged juvenile sand seatrout in four estuaries along the 8 mt. Currently, recreational harvest of sand west coast of Florida. The objectives of this study seatrout is unregulated in Florida. were to document recruitment windows for and Despite the ecological and economical impor­ seasonal changes in abundance of juvenile sand tance of sand seatroul, little is known regarding the life history of this species. Information is seatrout in shallow and deepwater areas and to widely scattered and sometimes conflicting (Ditty identifY factors that are associated with juvenile eta!., 1991). For instance, Copeland and Bechtel sand seatrout spatial occurrences in these estu­ (1974) found no relationship between catch aries. ratios and observed salinities, and Trent et a!. (1969) reported that sand seatrout distribution MATERIALS AND METHODS within an estuary was not related to salinity. Other studies, however, have identified optimal Study sites.-Juvenile sand seatrout were collected salinity ranges for this species within specific from four estuaries along the gulf coast of Published by The Aquila Digital Community, 2007 1 Gulf of Mexico Science, Vol. 25 [2007], No. 1, Art. 3 16 GULF OF MEXICO SCIENCE, 2007, VOL. 25(1) 86'0'0'W Suwannee River Estuary- Gulf of Mexico Tampa Bay Charlotte Harbor -==-=---o::::====---Kilometers 0 40 80 160 240 320 Fig. l. Locations of the four estuaries sampled for juvenile sand seatrout in Florida: Apalachicola Bay, Suwannee River estuary, Tampa Bay, and Charlotte Harbor. 2 Florida (Fig. 1). Apalachicola Bay (sampling area 575 km ), are not influenced by a single domi­ 2 approximately 411 km ) and the Suwannee River nant freshwater source, but only by numerous 2 estuary (sampling area approximately 731 km ) small rivers. Five such rivers with average annual 3 were the northernmost estuaries included in this discharges of 2-13 m s -I (USGS 2004) provide study; these areas were similar in that they are freshwater inflow into Tampa Bay, whereas two both characterized by substantial freshwater rivers, each with an average annual discharge of input (Livingston, 1983; Mattson and Rowan, 19m3 s- 1 (USGS 2004), flow into the Charlotte 1989) from the Apalachicola (mean annual Harbor estuary. 3 1 discharge 1,184 m s- ) and Suwannee rivers Bottom habitat throughout the four estuaries 3 (mean annual discharge 125 m s -I) (USGS consisted of cliiTering proportions of mud, sand, 2004), respectively. Additional sources of dis­ oyster bars, and seagrass. Salt marsh habitat (i.e., charge into these estuaries include the Carra­ SjJmtina. a.lternijlora and ]uncus roeme1ia.nus) was belle River (discharge data unavailable) in available in all four estuaries but was more Apalachicola Bay and numerous small, unme­ prevalent in Apalachicola Bay and the Suwannee tered tidal creeks in the Suwannee River estuary. River estuary than in Tampa Bay and Charlotte The southernmost estuaries, Tamra Bay (sam­ Harbor. Extensive mangrove habitat was sup­ pling area approximately 886 km ) and Char­ ported only in the Tampa Bay and Charlotte lotte Harbor (sampling area approximately Harbor estuaries. https://aquila.usm.edu/goms/vol25/iss1/3 2 DOI: 10.18785/goms.2501.03 Purtlebaugh and Rogers: Recruitment and Essential Habitat of Juvenile Sand Seatrout (Cyno PURTLEBAUGH AND ROGERS-JUVENILE SAND SEATROUT DISTRIBUTION 17 TABLE 1. Summary of sand seatrout (:5 100 mm SL) catch-and-effort data by gear type aud sampled area in Apalachicola Bay (Ap. = Apalachicola River and Cr. = Carrabelle River), Suwannee River Estuary (Su. = Suwannee River), Tampa Bay, and Charlotte Harbor estuaries, FL. 2 Gear Years Location No. hauls No. fish 100 Ill SE %occur Apalachicola Bay 21.3-m seine 2001-2003 bay 720 1,043 1.03 0.23 9 Ap. River 348 0 0.00 0.00 0 Cr. River 144 13 0.13 0.09 <1 Subtotal 1,212 1,056 6.1-m otter trawl 2001-2003 bay 432 2,194 0.35 0.07 27 Ap. River 180 3,806 2.69 1.51 15 Cr. River 72 1,534 2.90 0.85 54 Subtotal 684 7,534 Total 1,896 8,590 Suwannee River Estmuy 21.3-m seine 2001-2003 bay 747 877 0.84 0.21 15 Su. River 175 27 0.22 0.17 3 tidal creeks 324 664 3.03 0.52 24 Subtotal 1,246 1,568 6.1-m otter trawl 2001-2003 bay 350 1,612 0.33 0.13 9 Su. River 175 396 0.32 0.11 26 Subtotal 525 2,008 Total 1,771 3,576 Tampa Bay 21.3-m seine 2001-2003 bay 928 56 0.04 0.01 3 rivers 2,195 1,689 1.09 0.24 9 Subtotal 3,128 1,745 6.1-m otter trawl 1996-1997 bay 364 2,710 0.62 0.23 20 rivers 404 2,985 1.01 0.17 38 Subtotal 768 5,695 Total 3,896 7,440 Charlotte Harbor 21.3-m seine 2001-2003 bay 884 549 0.45 0.37 3 rivers 288 513 2.62 1.32 10 Subtotal 1,172 1,062 6.1-m otter trawl 1996-1997 bay 250 1,130 0.33 0.23 12 rivers 230 3,870 2.40 0.64 54 Subtotal 480 5,000 Total 1,652 6,062 Data collection.-Juvenile sand seatrout [:::; 100 walls, and beaches. "Offshore" deployments mm standard length (SL)] were collected during sampled shallow waters in the bays at least 5 m monthly stratified-random sampling using a bag away from a shoreline and sampled vegetated and seine and otter trawl (see Table 1 for estuary­ unvegetated flats. "River" deployments sampled specific effort). Data collections were made the shorelines of tidal creeks and rivers.