Tremain et al.: Sportfish species movements in relation to an estuarine no-take zone 



537 



tive migration rates were calculated as the percentage 

 of recaptured fish that migrated from their original 

 tagging location. These migration rates and their re- 

 ciprocal (retention rates) were compared between the 

 NTZ and the BR to determine the relative potential for 

 sportfish movements into or away from protected habi- 

 tats. Chi-square contingency tests for frequency data 

 (with Yates's correction for small sample sizes) were 

 used to test the hypothesis that recapture location was 

 independent of the tagging location. 



Results 



A total of 5951 fish of 27 species were tagged during 

 FMRI sampling within the IRL between September 1990 

 and December 1999. However, because 95% of these fish 

 were represented by only seven species (Table 1), which 

 included all fish that migrated across the reserve bound- 

 aries, only these seven species were considered further 

 in our analyses. Red drum (Seiaenops ocellatus) was 

 the most commonly tagged species (n=2064), followed 

 by black drum (Pogonias cromis, n = 1468), sheepshead 

 (Archosargus probatocephalus, /? =1117 ), common snook, 

 (Centropomus undecimalis, n = 510), spotted seatrout 

 (Cynoscion nebulosus, /; = 364), crevalle jack (Caranx 

 hippos, n=114), and bull shark (Carcharhinus leucas, 

 n=25). Approximately 41% (n=2307) of these fish were 

 tagged inside the boundaries of the NTZ. The remain- 

 der (« = 3355> were tagged in the surrounding lagoon. 

 Through August 2000, 403 tagged fish (7.1% of total) 

 were recaptured and reported either by FMRI staff 

 sampling in the lagoon or by the public. Overall recap- 

 ture rates were highest for red drum (12.9%), followed 

 by those for common snook (8.2%), bull shark, (8.0%), 

 black drum (3.6%), and sheepshead (3.0%). 



Tagged fish were generally representative of the larg- 

 er mobile members of the species and encompassed the 

 legally exploitable size ranges for species with man- 

 agement restrictions (Table 2). For species except the 

 bull shark and red drum, mean lengths of fish tagged 

 inside the NTZ exceeded those of fish tagged outside 

 the NTZ. 



Approximately 25% (n = W2) of the 403 total recap- 

 tured fish were fish originally tagged inside the NTZ 

 (Table 1). Thirty-seven of these fish were also recovered 

 inside the NTZ. including three red drum that were 

 subsequently recaptured on multiple occasions in the 

 protected area. The remaining 65 recaptured fish were 

 caught after emigrating to outlying waters, including 

 one red drum that was recaptured a second time outside 

 the NTZ. Species that migrated out of the NTZ were 

 red drum (n = 40, mean TL = 643 mm, SD = 135 mm), 

 common snook (;? = 9, mean TL = 570 mm, SD = 97 mm), 

 black drum (n = 8, mean TL = 845 mm, SD = 88 mm), 

 sheepshead (n = 6, mean TL = 398 mm, SD = 38 mm), 

 bull shark (n = l, TL=789 mm), and crevalle jack (n = l, 

 TL = 628 mm). Recapture distances ranged from km 

 immediately outside the NTZ to approximately 150 km 

 south in the St. Lucie River estuary, but recaptured 

 fish were more abundant closer to the NTZ (Fig. 2A). 

 Most of the recaptured fish were concentrated in areas 

 of high fishing pressure, such as causeways, inlets, and 

 waters near the boundary of the NTZ. Collectively, fish 

 that emigrated from the NTZ did not appear to show a 

 bias for any one direction of movement: recaptured fish 

 were found both northward in the Indian River and 

 southward throughout both the Indian River and Ba- 

 nana River basins of the lagoon. For individual species, 

 red drum that emigrated were distributed throughout 

 the lagoon system and coastal habitats, whereas black 

 drum were predominantly recaptured in the northern 



