36 



Fishery Bulletin 100(1) 



If the level of reporting can be closely estimated, then 

 this estimated value can be incorporated into models that 

 more accurately estimate sunival and escapement (Hoe- 

 nig etal.. 1998). 



In the past, researchers have attempted to accurately 

 estimate reporting for marked animals in a number of 

 ways. Some resource agencies have had creel clerks se- 

 cretly implant tags into recreational anglers' creel during 

 interviews, and others have conducted formal reward 

 studies. For example, in Texas (TXi, recreational anglers 

 reported only 28""/ of a number of species of estuarine and 

 marine finfish surreptitiously tagged by creel clerks (Mat- 

 lock, 1981). A small-scale study during which red drum 

 were surreptitiously tagged in Georgia (GA) also revealed 

 low reporting levels (.55'r )( Woodward- 1. The GA study also 

 noted trends in reporting by county and income level; how- 

 ever, because the number of tagged fish and subsequent 

 returns in this study were small, valid statistical compari- 

 sons could not be made (Woodward-). Rawstron (1971) in 

 a similar, more robust investigation conducted in freshwa- 

 ter lakes, found reporting levels of 50'i for tagged bluegill, 

 largemouth bass, and catfish and concluded that reporting 

 appeared to be site and species specific. 



Cash reward values <$50 have been used by many tag- 

 ging programs to assess reporting levels iRaw-stron, 1971; 

 Matlock, 1981; Murphy and Taylor, 1991). In most cases, 

 results have suggested that small cash awai'ds do not pro- 

 vide adequate incentive for anglers to report capture of 

 a tagged fish (Rawstron, 1971; Matlock, 1981; Murphy 

 and Taylor, 1991). Work in California with stocked trout 

 showed significantly higher reporting when a reward was 

 offered, rather than no reward (Butler, 1962). Butler con- 

 cluded that variability in reporting was also related to a 

 number of other factors, including degree of publicity, an- 

 gler interest in the fishery, and effort made to recover tags. 

 Difficulty in determining reporting is not unique to fish- 

 eries population modeling. Historically, bands have been 

 used to monitor populations of waterfowl and other birds. 

 Reporting of banded waterfowl has also been shown to dif- 

 fer between locations (Henny and Burnham, 1976; Con- 

 roy and Blandin, 1984). For example, in areas where mer- 

 chandise was regularly offered for banded birds, reporting 

 decreased as compared with areas where capture of a 

 marked bird was simply a novelty (Conroy and Blandin, 

 1984). Reward studies have attempted to overcome these 

 problems by offering higher monetary rewards. In a study 

 with waterfowl where rewards ranged from $5 to $1000, 

 Nichols et al. ( 1991 ) demonstrated that there was a corre- 

 lation between reporting and reward value. They also de- 

 termined the asymptote for 100% reporting by duck hunt- 

 ers occurred between a reward value of $75 and $100. In 

 a study of red drum in South Carolina (SC), Jenkins et 

 al. (2000) found that $50 was not a high enough value to 

 result in reporting differences between the standard "re- 

 ward" message and a "$50 reward" message. 



^ Woodward, A. G. 1992. Evaluation of fish tag reporting by 

 marine boat anglers in Georgia, 12 p. Georgia Department of 

 Natural Resources. Coastal Resources Division. 1 Consei-vation 

 Way, Brunswick, GA 31523. 



For modeling purposes fishery managers in the south 

 Atlantic region of the United States use reporting esti- 

 mates of -SC^r when analyzing return data for red drum. 

 This approximate figure is used even though previous 

 studies have shown that a number of variables may affect 

 the accuracy of reporting tagged animals (Butler, 1962; 

 Rawstron, 1971; Nichols et al., 1991; Ross et al., 1995; 

 Woodward-). Assigning an approximate reporting level 

 for the entire region could introduce bias in estimates of 

 exploitation and potentially lead to significant exploita- 

 tion of the population being managed. In previous studies 

 where reporting levels for red drum and other finfish spe- 

 cies were examined, there were a limited number of ex- 

 perimental units, making robust statistical analyses of the 

 data difficult (Murphy and Taylor, 1991; Woodward-'). This 

 shortcoming is primarily due to logistical problems associ- 

 ated with capture, tagging, and release of sufficient num- 

 bers of similar-size wild fish in a manner that will ensure 

 equal vulnerability to anglers over a large area (Yeager 

 and Van Den Avyle. 1979; Murphy and Taylor, 1991). Our 

 study attempts to reduce these problems by using similar- 

 size hatchery-produced fish to carry tags. This experimen- 

 tal model allows a high degree of control over the design 

 and implementation of a study (Jenkins et al., 2000). Fur- 

 ther, fish can be tagged and stocked during seasons of the 

 year when angler pressure is high, thereby minimizing 

 the time required for data acquisition, as well as reducing 

 variability associated with seasonal fluctuations in fishing 

 effort (Jenkins et al., 2000). To assess the veracity of the 

 currently used reporting estimate, a study was conducted 

 in two estuaries in SC and two in GA. It was expected that 

 the information obtained would provide a more accurate 

 estimate for use in modeling red drum population dynam- 

 ics in the south Atlantic region. 



Materials and methods 



All fish used in our study were progeny of locally cap- 

 tured wild broodstock. Adults had been spawned in tanks 

 by using photoperiod and thermal conditioning (Roberts 

 et al., 1978) at the SC Department of Natural Resources 

 (SCDNRi. Marine Resources Research Institute (MRRI) 

 in Charleston, SC. Three day-old larvae were stocked in 

 ponds at the SCDNR'sWaddell Mariculture Center (WMC) 

 in Bluffton, SC. Wlien fish had grown to a mean total 

 length (TL) of 200 mm, they were hai-vested and trans- 

 ported to MRRI. At MRRI, fish were gi-own to legal size 

 (356 mm TL) in 4-m diameter tanks. 



When fish were legal size (or approximately legal size), 

 they were anesthetized in groups in a 0.1-g/L solution of 

 MS-222 and culture water Fish were then individually 

 measured to the nearest mm and tagged with abdominal 

 anchor tags (Floy Tag and MFG Co., Inc., Seattle, WA). 

 In an effort to obtain results consistent with those from 

 ongoing mark recapture programs in each state, fishery 

 biologists from SC and GA tagged the fish to be stocked 

 in their respective state. In addition, the tags used were 

 identical to those used in ongoing studies in each state. 

 For SC releases Floy model FM-95W tags were used. 



