534 



Fishery Bulletin 102(3) 



or increased food and habitat availability could be ex- 

 pected to attract, or at least retain, individuals that 

 immigrate to the reserves from surrounding unpro- 

 tected habitats. Reserve areas that attract and retain 

 exploitable individuals from surrounding habitats at 

 higher rates than they replenish the surrounding habi- 

 tats could be considered to be sinks in terms of their 

 ability to directly supplement adjacent fisheries through 

 spillover of exploitable-size individuals. Fish emigration 

 from reserve habitats and the replenishment of nearby 

 fisheries is a commonly predicted benefit of harvest re- 

 serves (see reviews in Roberts and Polunin, 1991. and 

 Rowley, 1994). However, there are currently no studies 

 that simultaneously examine emigration and immigra- 

 tion in relation to estuarine reserves or that document 

 the extent to which reserve areas may also function to 

 withdraw individuals from surrounding fisheries. With- 

 out an assessment of net exchange, the interpretation of 

 reserve benefits with respect to replenishment cannot 

 be properly evaluated. 



The National Aeronautics and Space Administration 

 (NASA) closed a portion of the Indian River Lagoon at 

 the Merritt Island National Wildlife Refuge (MINWRi 

 on Florida's east coast for security purposes in 1962. A 

 direct result of this closure was the effective creation of 

 an estuarine no-take zone that remains to the present 

 time. The proximity of this no-take zone to productive 

 estuarine fisheries provided an opportunity to examine 

 sportfish movements in the area with mark-recapture 

 methods. Johnson et al. (1999) first documented sport- 

 fish migrations out of this no-take sanctuary, and in a 

 related study, Stevens and Sulak (2001) provided more 

 complete descriptions of movement patterns of indi- 

 vidual species; each of these studies provided evidence 

 that the restricted habitats protected fish populations 

 and that adult sportfish egressed into surrounding wa- 

 ters open to fishing. However, because all tagged fish 

 originated from within restricted habitats, in neither of 

 these studies was it possible to consider the potential 

 for the movements of fish into protected areas from 

 surrounding waters. Therefore, we (sponsored by tin- 

 Florida Fish and Wildlife Conservation Commission- 

 Florida Marine Research Institute [hereafter referred to 

 as FMRII Fisheries-Independent Monitoring Program) 

 tagged fish species throughout the northern Indian 

 River Lagoon system, including both the MINWR no- 

 take zone and the surrounding lagoon waters, from 

 1990 to 1999. We investigated the relationship between 

 sportfish egress and ingress in relation to the MINWR 

 no-take zone and offer a quantitative foundation for 

 the discussion of net fish movements into or away from 

 protected estuarine habitats. 



central east coast of Florida between Ponce de Leon 

 Inlet in Volusia County and Jupiter Inlet in Palm Beach 

 County. The lagoon is composed of three relatively iso- 

 lated basins: Mosquito Lagoon, the Indian River proper, 

 and the Banana River i Fig. 1). These three basins main- 

 tain hydrological connections with each other through 

 narrow man-made channels at Haulover Canal and 

 the Merritt Island Barge Canal (shown on Fig. 2) and 

 through a natural channel at the southern end of the 

 Banana River. Hydrodynamie exchange and fish passage 

 between the lagoon and the Atlantic Ocean occur pri- 

 marily through five inlets, which are concentrated in the 

 southern half of the system. The hydraulic lock system 

 located at Port Canaveral provides only an intermittent 

 opportunity for exchange between the IRL and Atlantic 

 Ocean. Gilmore et al. (1981) and Mulligan and Snelson 

 (1983) have provided detailed descriptions of the lagoon 

 and its habitats. 



The no-take zone (NTZ) created by NASA and MIN- 

 WR is located at the northern terminus of the Banana 

 River basin of the lagoon. An earthen causeway defines 

 the southern boundary of this no-access security area 

 and contains only two openings that permit fish to mi- 

 grate to and from adjacent waters. Much of the natural 

 shoreline and saltmarsh habitats in the lagoon have 

 been altered for mosquito control purposes. However, 

 actual shoreline habitats surrounding MINWR — in- 

 cluding the NTZ, the northern Banana River basin, 

 the northern Indian River basin, and Mosquito La- 

 goon — remain relatively undeveloped in comparison to 

 the urban shoreline development in the southern IRL. 

 Detailed descriptions of the habitat composition within 

 the NTZ and surrounding study area were provided by 

 Johnson et al. (1999). 



Data collection 



Fish were tagged as part of several related FMRI proj- 

 ects (stratified-random, fixed-station, and directed sam- 

 pling designs) in the northern IRL between 1990 and 

 1999 (FMRI 1 ). In most cases, tagging was conducted 

 opportunistically on healthy fish following capture in 

 multipanel monofilament gill nets, nylon trammel nets, 

 nylon haul seines, or on hook and line. In other cases, 

 projects were designed specifically to assess tag-recap- 

 ture information (Murphy et al., 1998). Because of the 

 focus of our sampling programs in this area, the major- 

 ity of our tagging efforts occurred north of Sebastian 

 Inlet within the Indian and Banana River basins of 

 the lagoon. A small percentage of tags were placed in 

 fish captured south of Sebastian Inlet or in Mosquito 

 Lagoon. Overall, our sampling collections in the NTZ 



Materials and methods 



Study area 



The Indian River Lagoon (IRL) is a shallow barrier 

 island estuarine system spanning 25.3 km along the 



1 FMRI (Florida Fish and Wildlife Conservation Commis- 

 sion). 1999. Florida Marine Research Institute. Fisheries- 

 independent monitoring program, 1999 annual data summary 

 report In-house Report. Florida Fish and Wildlife Conser- 

 vation Commission. Florida Marine Research Institute. LOO 

 Eighth Ave. S.E., St. Petersburg, Florida, 33701. 



