Gulf and Caribbean Research

Transcription

1 Gulf and Caribbean Researh Volume 15 Issue 1 January 23 Using a Modified Purse Seine to Collet and Monitor Estuarine Fishes Mihael R. Wessel Florida Marine Researh Institute Brent L. Winner Florida Marine Researh Institute DOI: /gr Follow this and additional works at: Part of the Marine Biology Commons Reommended Citation Wessel, M. R. and B. L. Winner. 23. Using a Modified Purse Seine to Collet and Monitor Estuarine Fishes. Gulf and Caribbean Researh 15 (1): Retrieved from This Artile is brought to you for free and open aess by The Aquila Digital Community. It has been aepted for inlusion in Gulf and Caribbean Researh by an authorized editor of The Aquila Digital Community. For more information, please ontat Joshua.Cromwell@usm.edu.

2 Gulf and Caribbean Researh Vol. 15, 61-71, 23 Manusript reeived September 3, 22; aepted January 15, 23 USING A MODIFIED PURSE SEINE TO COLLECT AND MONITOR ESTUARINE FISHES Mihael R. Wessel and Brent L. Winner 1 Florida Fish and Wildlife Conservation Commission, Florida Marine Researh Institute, 1 Eighth Avenue S.E., St. Petersburg Florida , Phone (727) , FAX (727) , brent. winner@jw.state.fl.us 1 Abstrat We developed a modified purse seine to sample shallow water estuarine habitats and evaluated the effiay of using this gear as a tool for monitoring estuarine fish populations in Tampa Bay, Florida. The purse seine (183-m long, 5.2 m deep and 5-mm streth mesh nylon throughout) was easily deployed and retrieved by a 7 m flat-bottomed, bow-driven boat with a hydrauli wenh and aluminum pursing davit. Retention rates of pinfish (Lagodon rhomboides) marked and released into 35 net sets averaged 49% (range 9-1%). Retention rates were not signifiantly influened by sets over vegetated and unvegetated bottom types, various water depths from 1-3.3m and sets with and without byath. We then used the modified purse seine to sample fishes at 55 randomly seleted sites in Tampa Bay from January 1997 to Deember Sampled habitats ranged from 1. to 3.3 m deep and inluded seagrass beds and non-vegetated sand or mud bottoms. Benthi, demersal, and pelagi fishes were aptured, indiating the purse seine effetively sampled the entire water olumn. A wide size range of fishes was olleted inluding pre-reruitment sizes of several eonomially important speies. The ability of purse seines io fish independent of adjaent shorelines allowed us to sample nearshore waters that inluded large expanses of sea grass meadow. Florida's Fisheries-Independent Monitoring (FIM) program monitors the relative abundane of fish stoks in seven estuaries around the state inluding Tampa Bay. Gear used by the FIM program inludes smallmesh seines to sample juvenile fishes reruiting to shallow waters and trawls designed to apture these juveniles in the deeper parts of the estuary (Nelson 1998). Large haul seines are used to ollet large-juvenile and adult fishes and have proven to be effetive for this purpose (Kupshus and Tremain 21); however, this gear is restrited to use along shoreline habitats. Our interest was to expand our sampling of large fishes (> 75 mm) to inlude areas away from the shoreline in Tampa Bay. The ability of purse seines to sample the entire water olumn, and to fish areas away from the shoreline, made it a promising gear for this purpose. Tampa Bay is a shallow estuary with a modal depth of 3 m and a shallow shelf along the periphery that varies in width from 5 m to 1,2 m (Lewis and Estevez 1988). Muh of this nearshore estuarine environment inludes expansive seagrass meadows. Seagrasses are known to influene the abundane and diversity of ihthyofauna in Florida estuaries and are well dou- mented as ritial habitat for many fish speies (Stoner 1983, Compand Seaman 1985, Sogard et al. 1989), but historially have been under-sampled by our program. The purpose of this study was to: 1) design a purse seine and vessel suitable for fishing estuarine waters to 3.3 m deep; and 2) evaluate the effiay of using this gear through gear retention experiments and random sampling as part of the FIM program's objetives to monitor INTRODUCTION Purse seines have been used for enturies to apture pelagi fishes in subsistene fisheries throughout the world (Ben-Yami 1994). During the 2th entury, purse seines revolutionized several important ommerial fisheries in the United States, inluding Paifi tuna and Atlanti menhaden fisheries (MNeely 1961, June 1972, Shaaf and Huntsman 1972). In the Gulf of Mexio, purse seines are used in the Gulf menhaden fishery, whih reports an average of 56,5 metri tons landed per year (Smith et al. 22), and the Florida baitfish fishery, whih supports a multimillion dollar industry in Florida (Piere and Mahmoudi 21). Though widely used in ommerial fisheries, purse seines have been used by sientists onduting fisheries-independent studies only when traditional sampling gears were inadequate for the researhers' needs. Hunter et al. (1966) used a 'miniature' purse seine to ollet juvenile pelagi fishes that ongregated beneath floating material at sea. Levi ( 1981) developed a two-boat purse seine to ollet menhaden for mark and reapture experiments. Both authors found the purse seine to be suitable as a olletion gear and ommented on its potential in fisheries siene. Despite these uses and Kjelson and Colby's (1977) speifi suggestion that purse seines be developed for monitoring estuarine fish populations, our study in Tampa Bay, Florida, douments the first known use of a purse seine in a multispeies fisheries-independent study with a random-sampling design. 61

3 WESSEL AND WINNER large-juvenile and adult fish populations in Tampa Bay, Florida. MATERIALS AND METHODS Gear desription The 183 m purse seine used in this study was a saled-down version of ommerial purse seines used in Florida's baitfish industry. The body (wing) of the net was onstruted of 5 mm streth mesh knotless #242 nylon twine and was 5.2 m deep. Football floats (Os2) were spaed every 61 em and pipe leads were spaed every 3 em along the body of the net. The bunt end (bag) was 16m long x 7 m deep and onstruted of 5 mm knotted #15 nylon. Floats were positioned more tightly together along the bag of the net to minimize esapement during net retrieval. Stainless steel alpine lips (1 em long) were used for purse rings and were attahed to the lead line of the net with lengths ( em) of 1 mm polypropylene line. Purse rings were spaed 3.1 m apart on the wing and 1.5 m apart on the bag. The purse line was a single length (25m) of 1 mm low-streth nylon yaht braid. Vessel Desription The vessel used in this study was a 7 m mullet skiff; a flat-bottomed, bow-driven boat apable of running in shallow water ( < 1 m). The skiff had a large, open netwell that allowed the purse seine to be deployed quikly from the stern. We modified the mullet skiff by installing a hydrauli system and an aluminum pursing-davit (Figure 1). A 4-L hydrauli system was driven by an 8- hp engine oupled to a gear pump that reated 72.5 KPa (5 psi) at 2,5 revolutions p~r minute. Attahed to the pursing-davit were a apstan and net roller used to retrieve the net. A dual-iruit hydrauli valve was used to ontrol the apstan and the net roller independently. The apstan was 15 em in diameter, turned at 75 revolutions per minute and retrieved the purse line at a rate of approximately 11 m per minute. A 14 mm stainless steel rod (ring bar) held the purse rings in position, and a 45 kg tom weight kept the purse line on the bottom while the net was being pursed. The ost of net onstrution, purse rings, tom weight and purse line was about US$12, and vessel modifiations inluding aluminum davit and hydrauli omponents ost an additional US$2,5. Deployment of the purse seine was similar to that desribed by Ben-Yami (1994 ). In estuarine onditions where tidal urrents affeted the set, we standardized the shape of the set to an oval pattern to minimize the amount of net set aross the urrent (Figure 2). An average set sampled a. 2,21 m 2 and required 25 minutes to deploy and retrieve the gear. 9 Figure 1. Mullet skiff and equipment used to onvert the skiff to a purse seiner. 1 =mullet skiff, 2 =ring bar, 3 =tom weight, 4 =hydrauli motor, 5 =apstan, 6 =bloks, 7 =net roller, 8 =outboard engine, 9 =dual-iruit hydrauli valve, 1 = 8 hp gas engine w/oupled hydrauli gear pump, 11 = 4-L hydrauli tank. 62

4 EsTUARINE PuRsE SEINE CurrenVWind Mean retention rate and assoiated variane was alulated using the ratio estimator desribed by CharlesDominique (1989). We assumed that marked and unmarked fish were equally apable of esaping during the retrieval proess. Retention rate estimates were subjeted to normality tests (Shapiro-Wilks test: Zar 1996) whih indiated a normal distribution. The Student's two-sample t-test was then used to test retention rate differenes between vegetated and unvegetated bottom types, presene or absene of byath, quantity of byath (-38 L vs > 38 L), and water depth ( < 1.6 m vs m). Bag ~~ ~r~~~~~~~~ v~~ :) Boat ~ Marked Float ~~~~----, ~Tom "..., Weight P" 1(>()('XX1 ~.-;3~~~1- Purse Line -' Random Sampling After thoroughly field testing the modified purse seine, we inorporated it into the FIM program's Tampa Bay random-sampling design beginning in January Sampling loations were randomly seleted eah month from all possible sites in Tampa Bay < 3.3 m in water depth. Sampling effort was distributed evenly throughout the available sampling area in Tampa Bay. At eah sample loation, we,reorded environmental variables suh as water depth, bottom type, by-ath type and quantity, and abioti variables (i.e., temperature ( C), salinity (%o), dissolved oxygen (mg/ml), and ph). Captured fishes were identified in the field to the lowest pratial taxon and enumerated. At least 2 randomly seleted individuals of eah speies olleted in eah sample were measured to the nearest millimeter standard length (SL). Length statistis were generated for all speies and density estimates alulated for speies where more than 1 individuals were olleted. Length-frequeny histograms were plotted for four ommonly olleted speies of eonomi importane. Density estimates (Number of fish/1 m 2 ) and Shannon-Wiener diversity (H') estimates were alulated for eah set and their distributions tested for normality. Due to signifiant departures from normality, the Wiloxon rank-sum test was used to ompare density and diversity estimates between sets over vegetated and unvegetated bottom types. p.,_ Lead / Purse Rings Marked Float ".J "1'--r-.A \ ~~t-line YX><:';/4..-L'- Float ~ )j...--line Figure 2. Diagram of a typial 183-m purse seine set in estuarine onditions. Set is made in an oval shape and started into the urrent. Gear Retention We designed an experiment to estimate purse seine gear retention using mark and reapture tehniques. We onduted the experiment in lower Tampa Bay in an area with expansive seagrass meadows and unvegetated sand/silt bottom. Sets were stratified by water depth (i.e., < 1.6 m or m). Finfish (Lagodon rhomboides), the most abundant speies available during gear testing trials, were used for the experiment. Experimental animals were olleted, measured (SL, mm), marked by lipping a portion of the anal fin, and held in the net well of a seond (release) boat until approximately 6 fish were olleted for an experimental set. Only pinfish in good ondition and;::: 15 mm SL and 45 mm body depth (42 mm was the inside dimension of the 5 mm streth-mesh knotless nylon twine, as measured on a wet net using digital alipers) were used in the experiment to avoid effets of mesh seletivity on retention estimates. Marked fish were released throughout the area enirled by the net one the wing and bag end were together and the tom weight was on the bottom. The net was then pursed and all fish olleted. Captured fish were measured and heked for fin lips (marks). The number of reaptured fish was reorded for use in retention estimates. RESULTS Gear Retention A total of 2,15 pinfish were marked and used in thirty-five repliate gear-retention trials. The trial's mean retention rate was 49% and ranged from 9% to 1%, with a oeffiient of variation (CV) of 45%. Retention rates were not signifiantly different between sets over vegetated and unvegetated bottom types or 63

5 WESSEL AND WINNER TABLE 1 Mean retention rates and results of Student's two-sample t-test for variables reorded in assoiation with experimental purse seine mark and reapture sets. Number Variable Level of sets Bottom vegetation Sea grass 22 No seagrass 13 Water depth Shallow ( < 1.6 m) 18 Deep ( m) 17 Byath Presene 19 Absene 16 Byath quantity Low(< 38 L) 24 High(> 38 L) 11 Mean Std. Dev. t-value %Retention (diff.) (P-value) (.67) (.334) (.63) (.143) sets in shallow ( < 1.6 m) and deep water ( m). Retention rates were also not affeted by presene or quantity of byath (Table 1). Random Sampling The purse seine was deployed in shallow-water ( < 3.3 m) habitat types, inluding seagrass flats and sand and mud bottoms, throughout Tampa Bay, Florida. Most sets took plae more than 1m from an adjaent shoreline, and less than 2% of the sets ourred over seagrass (vegetated: n = 93, unvegetated: n = 457). Typially, five net sets were ompleted in a sampling day. Mean set time, inluding sample proessing, was 45 minutes and varied with size of the ath. In 55 purse seine sets, 54,82 individuals representing 84 fish speies were olleted, ranging in size from 25 mm to more than 1, mm SL (Table 2, Figure 3). The purse seine ath inluded both juvenile and adult fishes. Demersal (n = 34), pelagi (n = 34), and benthi speies (n = 16) omprised 52%, 45%, and 3% of the total ath, respetively. Density and diversity estimates were signifiantly higher (density P <.1; diversity P =.48) in sets over vegetated bottom types (Figure 4). The purse seine ath was dominated by pinfish, whih were olleted in 48% of the hauls and made up 25% of the total ath. Clupeids, inluding Opisthonema oglinum (threadfin herring), Brevoortia spp. (menhaden), and Harengula jaguana (saled sardine), omposed 25% of the total ath. Siaenids, inluding Bairdiella hrysoura (silver perh), Leiostomus xanthurus (spot), Mentiirrhus amerianus (southern kingfish), Cynosion arenarius (silver seatrout), and Cynosion nebulosus (spotted seatrout), omposed an additional 13% of the total ath. Many of the speies (n = 27) olleted were of eonomi importane, omposing about 2% of the total ath (Table 2). The most abundant eonomially important speies in the ath were Elops saurus (ladyfish), spot, silver seatrout, spotted seatrout, Paralihthys albigutta (southern flounder), and southern kingfish. Length-frequeny distributions for several eonomially important fish speies inluded modal sizes refleting ohorts of pre-fishery reruits (Figure 5). DISCUSSION We developed, tested, and implemented a modified purse seine for sampling estuarine fish populations in Tampa Bay, Florida. We found that the purse seine ould be onsistently set in a variety of estuarine habitat types and that the sample area was easily standardized and quantified. The purse seine is an ative gear, and the dimensions and design of the net haraterize how and where it may be fished. Our net was designed to sample the entire water olumn in depths of m. The maximum depth fished by this type of purse seine is simply limited by the depth of the webbing used. The maximum depth for our net was seleted based upon the topography of Tampa Bay (modal depth=,.., 3 m) and our desire to sample deep seagrass beds, previously under-sampled with other gear types used by our program. Seagrass beds are ritial habitat for many fish speies (Comp and Seaman 1985, Sogard et al. 1989, Rozas and Odum 1988). 64

6 EsTUARINE PuRsE SEINE TABLE 2 Speies olleted with a 183-m purse seine in Tampa Bay from January 1997 through Deember 1998 (55 sets). Speies are listed by dereasing order of number of individuals olleted and density estimates and frequeny of ourrene (%) are provided where greater than 1 individuals were olleted. Speies of eonomi importane are indiated by '$'. Speies Individuals Density Standard Colleted Fish/1 m 2 length (mm) (% Ourrene) Mean Range Lagodon rhomboides 13, (48.7) Opisthonema oglinum 7, (23.6) $ Elops saurus 5, (27.8) Harengula jaguana 4, (27.6) $ Leiostomus xanthurus 3, (16.5) Arius felis 3, (48.9) Bairdiella hrysoura 2, (16.4) Brevoortia spp. 1, (11.5) Orthopristis hrysoptera 1,3 1.7 (21.5) Chaetodipterus faber 1, (13.6) Euinostomus gula 1, (22.) Rhinoptera bonasus 1,38.85 (29.3) Dasyatis sabina (43.1) Chilomyterus shoepfi (43.1) Latophrys quadriornis (4.2) Chlorosombrus hrysurus (16.2) $ Cynosion arenarius (11.1) $ Cynosion nebulosus (23.6) Bagre marinus (19.3) Prionotus situlus (35.5) Caranx hippos (7.1) $ Paralihthys albigutta (2.7) $ Mentiirrhus amerianus (11.5) Aluterus shoepfi (8.2) Euinostomus harengulus (4.9) Dasyatis say (12.2) $ Somberomorus maulatus (1.4) Monaanthus hispidus Synodus foetens $ Pomatomus saltatrix Oligoplites saurus Sphoeroides nephelus Caranx rysos Trinetes maulatus Ahirus lineatus $ Arhosargus probatoephalus $ Mentiirrhus saxatilis Rhinobatos lentiginosus Peprilus alepidotus $ Mugil gyrans Selene vomer

7 WESSEL AND WINNER Table 2 (Continued) Speies Individuals Density Standard Colleted Fish/1m 2 length (mm) (% Ourrene) Mean Range Prionotus tribulus Opsanus beta $ Trahinotus falatus Diplodus holbrooki $ Mugil ephalus $ Lutjanus griseus $ Haemulon plumieri Hippoampus eretus Niholsina usta Symphurus plagiusa $ Sphyrna tiburo $ Trahinotus arolinus Anylopsetta quadroellata Gymnura mirura Dorosoma petenense Eheneis naurates Latophrys trigonus $ Myteropera mirolepis $ Rahyentron anadum Dasyatis ameriana Deapterus puntatus Calamus artifrons Diapterus plumieri $ Centropristis striata Hemiaranx amblyrhynhus Lutjanus synagris Aluterus sriptus $ Centropomus undeimalis Sorpeana brasiliensis $ Mentiirrhus littoralis Ogoephalus radiatus Lepisosteus osseus ,5 $ Siaenops oellatus $ Mugil urema Caranx ruber Dipletrum formosum Etropus rossotus $ Miropogonias undulatus Astrosopus y-graeum 1 11 Aetobatus narinari 525 Hippoampus zosterae Hyporhamphus unifaiatus Lepisosteus platyrhinus 1,5 66

8 ESTUARINE PURSE SEINE 25 Seines 2 >. 2,424 hauls (.) 15 n=1,25,698 ::::::1 "' I- u.. ~ 1 5 1' =.. ~ Trawls 2 >. (.) 2,359 hauls 15 n = 316,98 ::::::1 "' 1... u.. ~ Purse seines >. (.) 55 hauls 15 n = 54,82 :::J "' I- u.. ~ Gill nets >. (.) 56 hauls 15 n = 19,438 :::J "' I- u.. ~ 1 5 I Standard Length (mm) Figure 3. Overall length-frequeny distributions (SL mm, all speies ombined) offish aptured in small seines ( seasonal), trawls ( seasonal), purse seines ( , urrent study), and gillnets ( seasonal, nighttime) olletions onduted by the FIM program in Tampa Bay, Florida. 67

9 WESSEL AND WINNER 2 1. P=.48 p <.1 C\1 E T"" ~..: en 1 u; ~ u::: u;.5 I... > Grass Nongrass Bottom type -, , Grass Nongrass Bottom Type Figure 4. Box and whisker plots of Density (Fish/1m 2 ) and Shannon-Wiener diversity estimates (H') in Tampa Bay purse seine sets over vegetated (n = 93) and unvegetated (n = 457) bottom types in Tampa Bay Median estimates (horizontal line) and 2Sth and 75th quartiles (box) are shown with 5th and 95th perentiles as the whiskers. fish greater than 75 mm SL. Length frequeny distributions showed that purse seine samples ontained the highest proportion of fishes between 1 mm and 2 mm SL (Figure 3). This size lass of fishes was dominated by pinfish, small oastal pelagis (e.g., saled sardine, threadfin herring), and other speies that are important trophi links between primary produers and a variety ofpisivorous fish speies (Seaman and Collins 1983, Sogard et al. 1989, Piere and Mahmoudi 21). Raw ath data an be inaurate without estimates of gear effiieny (Kjelson and Colby 1977). Sine either esapement or avoidane an affet effiieny of a gear, retention estimates are an important part of understanding the overall effetiveness of a fishing gear. A voidane estimates were beyond the sope of our study; however, estimating the rate at whih a gear type retains fish an be used as an upper estimate of the effiieny of a gear (Charles-Dominique 1989). Variability in retention rates in our study was onsistent aross several omparison groups (bottom type, water depth, and byath) suggesting purse seine effiieny was stable over a variety of estuarine onditions. Purse seine retention rates and variability in our study were similar to many other types of gear that are routinely used in fisheries siene. Kjelson and Johnson ( 197 4) reported retention rates ranging from 1% to 6% for a large offshore pull-through seine, and CharlesDominique (1989) estimated retention rates for their purse seine at between 1% and 79% using tehniques similar to those employed in our study. Kjelson and Colby ( 1977) reported gear-effiieny estimates (whih The purse seine provided valuable data on the diverse fish ommunities inhabiting nearshore environments of Tampa Bay. We olleted a variety of fish speies and a wide size range using the purse seine. The design of the gear allowed us to ollet benthi (e.g., southern flounder, Dasyatis sabina [atlanti stingray]), demersal (e.g., pinfish, silver perh), and pelagi (e.g., menhaden, saled sardine) fish speies. Pre-reruitment size lasses for several speies of rereational or ommerial importane were represented. Colletions of eonomially important speies (e.g., ladyfish, spot, spotted seatrout, silver seatrout), provided us with lifehistory data later used to develop age-length keys for ongoing fisheries management purposes (Table 2). The FIM program's previous attempts to haraterize large-juvenile and adult fish populations assoiated with Tampa Bay's nearshore estuarine environments inluded the use of 6.1 m otter trawls and multi-panel gillnets (2" to 6" strethed mesh). These types of gear were deidedly unprodutive for this purpose (MMihael 1995). Trawls sampled only near the bottom and rarely aptured fishes greater than 75 mm in SL (Figures 3 and 5), while gillnet effetiveness relied on nighttime sampling and extended soak-times (a. 1.5 hours not inluding time for retrieval and sample work up) that redued the number of samples that ould be olleted in a given sampling trip. Further, gillnet seletivity and their use as a passive gear, limits their effetiveness for multi-speies surveys (Rozas and Minella 1997). Our aim in developing the purse seine was to omplement the ath of seines and trawls by olleting 68

10 Cynosion arenarius Cynosion nebulosus Elops saurus Somberomorus maulatus 4, , 4 4.-rn , w n = 24,37 n = 529 I I 1 n = 7 n = 1 8 ~ j ~ ~ llllllo.. n -J-I'L "'---r----'"'--., ! o ,...-lll ~ Trawls \ \ , , , , n = 674 n = 551 n = 5,215 n = """" -J----.,..--'LDLII I n~l l!l ll~~~lllmi~~hon Purse seines , 4, , , , 3 n = n = n = 1,59 o "jrl!jll. I!!"'"" DIII!!!!!IIUIIII!tlor11# 1!D!!JU n " l nnti!hi!l fuiiuuiiihuuiu!uoiuj n I ,.----P-.lL..UWI Standard Length (mm) Standard Length (mm) Standard Length (mm) Standard Length (mm) Gillnets n = 64 t'rj..., en ;J:> ~ z tt1 "" ::: en tt1 (/). tt1 z tt1 Figure 5. Length-frequeny distributions (SL mm) offour speies of eonomi importane olleted using trawls ( seasonal), purse seines ( , urrent study), and gillnets ( seasonal, nighttime) by the FIM program in Tampa Bay, Florida.

11 WESSEL AND WINNER Quinn, J. Leiby, and L. Frenh for their helpful omments and suggestions for improving this manusript. This work was supported in part by the Department of the Interior, US Fish and Wildlife Servie Federal Aid for Sport Fish Restoration, Grant Number F-43 to the Florida Fish and Wildlife Conservation Commission's Florida Marine Researh Institute and by the State of Florida Rereational Saltwater Fishing Liense funds. inluded avoidane estimates) for a variety of sampling gears (i.e., plankton net, beam trawl, portable drop net, haul seines, and otter trawls) that ranged from 5% to 8%, and similar variability in gear-effiieny estimates have been reported by other authors as well (Weinstein and Davis 198, Parsley et al. 1989). Rozas and Minella (1997) reommended enlosure gears, inluding purse seines, for sampling shallow estuarine waters due to their generally higher ath effiieny and ease in quantifiation of the sample area; however, purse seines were not reommended for use over seagrass. In ontrast, our purse seine performed reliably well over vegetated bottom types and provided important information on fish speies utilizing these ritial habitats. In onlusion, the use of a purse seine has enabled our program to obtain quantitative information on large juveniles and adults of benthi, demersal, and pelagi fishes inhabiting estuarine waters of Tampa Bay, Florida. This gear allowed our program to adequately sample a variety of estuarine habitats in whih previous attempts using trawls and gillnets had been less suessful. Geareffiieny estimates for our purse seine based on retention-rate experiments were omparable with those of other types of sampling gear typially used in fisheries siene, and the purse seine was durable enough for standard field use. The purse seine had limitations, as do other gear types. It was suseptible to strong tidal urrents and winds, whih aused the lead line to roll, twisting the purse line and rings into the webbing. Further, the gear ould not be fished properly in areas with obstrutions or hard bottom, that snagged the net or purse line. Finally, the initial osts assoiated with building a purse seine, and the vessel to work the gear, were onsiderable (about US$15,). Future studies will onentrate on the versatility of the purse seine as a sampling tool in other Florida estuaries and omparisons with the ath of large haul seines used along shoreline habitats, providing more information on the benefit of this gear type as an eologial fish-monitoring tool. LITERATURE CITED Ben-Yami, M Some priniples onerning the design of purse seines. Infofish International, May, 1994: Charles-Dominique, E Cath effiienies of purse and beah seines in Ivory Coast lagoons. Fishery Bulletin, US 87 : Comp, G.S. and W. Seaman, Jr Estuarine habitat and fisheries resoures of Florida. In: William Seaman Jr., eds. Florida aquati habitat and fisheries resoures. Florida Chapter of the Amerian Fisheries Soiety, Eustis, FL, USA, p Hunter, J.R., D.C. Aasted, and C.T. Mithell Design and use of a miniature purse seine. Progressive Fish-Culturist 28: June, F.C Variations in size and length omposition of Atlanti menhaden groupings. Fishery Bulletin, US 7(3): Kjelson, M.A. and D.R. Colby The evaluation and use of gear effiienies in the estimation of estuarine fish abundane. In: M.L. Wiley, ed. Estuarine proesses. Aedemi Press, New York, NY, USA, p Kjelson, M.A. and G.N. Johnson Desription and evaluation of a long-haul seine for sampling fish populations in offshore estuarine habitats. Proeedings, 28th Annual Conferene of Southeastern Assoiation of Game and Fish Commissioners, Frankfort, Ky, USA, Date, p Kupshus, S. and D. Tremain. 21. Assoiations between fish assemblages and environmental fators in nearshore habitats of a subtropial estuary. Journal of Fish Biology 58: Lewis, R.R. and E. Estevez The eology of Tampa Bay, Florida: An estuarine profile. US fish and Wildlife Servie Biologial Report. 85(7.18), p Levi, E.J Design and operation of a small two-boat purse seine. Estuaries 4( 4): MMihael, R.H Fisheries-Independent Monitoring Program: Annual Report. IHR Florida Marine Researh Institute, St. Petersburg, FL, USA. MNeely, R.L The purse seine revolution in tuna fishing. Paifi Fisherman. June, Nelson, G.A Abundane, growth and mortality of youngof-the-year pinfish, Lagodon rhomboides, in three estuaries along the gulf oast of Florida. Fishery Bulletin, US 96: Parsley, M.J., D.E. Palmer, and R.W. Burkhardt Variation in apture effiieny of a beah seine for small fishes. North Amerian Journal of Fisheries Management 9: AKNOWLEDGEMENTs The authors extend their appreiation to staff of the Fisheries-Independent Monitoring program for their ontinuous efforts in implementation and testing of this gear. We also thank the Mora family of Cortez, Florida, and D. Morave and Custom Sea Gear for their efforts in the development and refinement of equipment used in this projet. We would like to thank D. Leffler, G. Poulakis, D. Nemeth, R. Hensley, Dr. B. Mahmoudi, J. 7

12 EsTUARINE PuRSE SEINE Piere, D.J. and B. Mahmoudi. 21. Nearshore fish assemblages along the entral west oast of Florida. Bulletin of Marine Siene 68(2): Rozas, L.P. and T.J. Minello Estimating densities of small fishes and Deapod rustaeans in shallow estuarine habitats: A review of sampling design with fous on gear seletion. Estuaries 22(1): Rozas, L.P. and W.E. Odum Oupation of submerged aquati vegetation by fishes: Testing the role of food and refuge. Oeologia 77: SAS Institute In SAS/STAT User's guide, 5th edition SAS Institute In. Cary, NC, USA. Shaaf, W.E. and G.R. Huntsman Effets of fishing on the Atlanti menhaden stok. Transations of the Amerian Fisheries Soiety 11(2): Seaman W., Jr. and M. Collins Speies profiles: Life histories and environmental requirements of oastal fishes and invertabrates. US Fish and Wildlife Servie FWS/ OBS-82/ Smith, J.W., E.A. Hall, N.A. MNeil, and W.B. O'Brier. 22. The distribution of purse seine sets and athes in the Gulf Menhaden fishery in the Northern Gulf of Mexio. Gulf of Mexio Siene 2(1): Sogard, S.M., G. Powell, andj. Holmquist Utilization by fishes of shallow-water seagrass banks in Florida Bay: 2 diel and tidal patterns. Environmental Biology of Fishes 24(2): Stoner, A.W Distribution of fishes in seasgrass meadows: role ofmarophyte biomass and speies omposition. Fishery Bulletin, US 81(4): Weinstein, M.P. and R. W. Davis Colletion effiieny of seine and rotenone samples from tidal reeks, Cape Fear River, NC. Estuaries 3(2): Zar, J.H Biostatistial Analysis. 3rd Edition. Prentie Hall, Upper Saddle River, NJ, USA, p