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Fisheries Research 105 (2010) 215–227

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Fisheries Research

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Evaluation of bag-and-size-limit options in the management of summer ﬂounder Paralichthys dentatus

Eric N. Powell a,∗, Eleanor A. Bochenek a, John DePersenaire b a Haskin Shellﬁsh Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 6959 Miller Ave., Port Norris, NJ 08349-3167, USA b Recreational Fishing Alliance, 176-B South New York Road, Galloway, NJ 08205, USA article info abstract

Article history: The conundrum probed here is the seeming divergence in outcomes of the management program Received 28 September 2009 presently in place in the Mid-Atlantic Bight for summer flounder; namely that increasing restrictions Received in revised form 14 April 2010 on catch to limit quota exceedances and maintain satisfaction in the fishing experience for the angler Accepted 26 May 2010 may not be simultaneously achievable. The corollary quandary is the loss of the bag limit as an operative management tool, as efforts to restrain landings became increasingly burdensome, thereby placing inor- Keywords: dinate reliance on the size limit (and season). To investigate options that might promote increased angler Summer flounder gratification and reduce discard mortality without eliciting quota exceedances, we examine a number of Recreational fishery Size limit alternative management strategies that might (a) bring bag limits back into the manager’s repertoire, (b) Discard mortality trade discards for landings, thereby increasing angler gratification, and (c) provide an increased number Fisheries management of fish per unit of landings weight, thereby realizing for the angler a greater number of kept fish. Options investigated include standard bag-and-size limits, boat limits, dual-size limits implemented with both a minimum and maximum size, slot limits, and a cumulative-size limit in which landings are restrained by a total number of inches of landed fish. Comparing all fishery options reveals that dual-size, slot, and cumulative-size limits provide the best resolution to the posed conundrum. Dual-size and slot limits improve landings relative to fishing mortality, but the cumulative-size limit outperforms both by a substantial degree. The options in part permit increased landings relative to discards and this moves discard mortality to landings, a useful outcome. However, the probability of mortality due to discard is low in summer flounder and, thus, relatively little gain occurs in simply minimizing discards. Rather, successful management options are those that permit effort to be transferred from larger fish to smaller fish, thus reducing total weight landed relative to total number. The cumulative-size limit is the most successful approach in accomplishing this feat. © 2010 Elsevier B.V. All rights reserved.

1. Introduction der management plan. This plan was approved by the NMFS2 and the MAFMC3 in 1988. Since 1993, an annual harvest limit, which Stock rebuilding of summer flounder, Paralichthys dentatus, includes landings and discards, has been used in the management since the early 1990s has posed a series of conundrums for man- of the recreational fishery; however season, bag, and size limits agement as efforts have been made to restrict fishery landings are set by individual states to meet state-distributed quotas. As a to promulgated yearly quotas while increases in stock abundance consequence, the recreational sector has exceeded harvest limits abetted expanding angler catch. Summer flounder is one of the in many years, at least in a few states. most sought-after recreational fish along the Mid-Atlantic coast Approaches to limit landings in the recreational summer floun- from Massachusetts to North Carolina. This species has a long der fishery include shortened fishing seasons, increased minimum association with recreational anglers due to its accessibility to legal sizes, and reduced bag limits. Over the last decade as the most fishermen. Terceiro (2002) reviewed the history of summer summer flounder population was rebuilding and the size structure flounder management. Overfishing occurred at least as early as improving (NEFSC, 2000; Terceiro, 2003, 2006), the minimum size the 1970s. In 1982, the ASMFC1 created the first summer floun- limit became the primary limiter of landings. As a consequence of steadily increasing minimum size limits, larger and heavier fish

∗ Corresponding author. Tel.: +1 856 785 0074 x4309; fax: +1 856 785 1544. E-mail address: [email protected] (E.N. Powell). 2 National Marine Fisheries Service. 1 Atlantic States Marine Fisheries Commission. 3 Mid-Atlantic Fisheries Management Council.

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Table 1 Summary of pertinent results from the study of Bochenek et al. (in press).

Mean Median Maximum Mean Median Maximum Mean Median Maximum Biomass neutral catch catch catch kept kept kept discarded discarded discarded increase in landings

2006-legal 3.6 2.0 21.3 0.3 0.2 1.7 3.3 1.8 21.3 1.00 Cumulative size 3.4 2.9 9.2 1.8 1.6 4.3 1.5 1.0 6.2 2.09 Reduced minimum size 3.2 2.2 13.3 1.7 1.5 4.8 1.4 0.9 9.1 2.06 Slot limit 3.7 2.4 25.5 1.3 1.2 3.3 2.3 0.9 21.9 1.75

Bochenek et al. (in press) evaluated a series of alternative approaches to bag-and-size limits that might minimize discard mortality while increasing angler satisfaction by increasing the number of fish landed. They tested three alternatives, a slot limit, a reduced minimum size, and a cumulative-size limit that conflated bag limit and size limit on a series of party-boat trips in New York and New Jersey and compared these outcomes to trips taken on the same boats under the state regulations for that year (2006). They found that total catch by number was lowest on the 2006-legal trips and higher for all three experimental regulatory scenarios, because the latter resulted in more kept fish. The three experimental scenarios resulted in lower discard-to-catch ratios, as expected. All three experimental scenarios resulted in the landing of more fish under a biomass-neutral fishery to retain catch within allocation limits. Comparison to 2006-legal conditions under the biomass-neutral proviso showed that from 1.75 to 2.09 more fish were landed, while discard mortality was reduced 41–63%, yet, as defined, the total fishing mortality by weight remained unchanged. The summary data from this study provided in this table include the mean, median, and maximum catch per angler per trip (both kept and discarded), the same statistics separately for the fish kept and discarded, and the estimated increase in landings for the alternative regulatory scenarios under a biomass-neutral assumption. This last statistic is the factor increase in numbers of fish landed given the restriction that the biomass of fish landed + the discards that died remained invariant. Thus, a value of 1.0 implies that the number of fish landed was the same as was landed under the 2006-legal regulations. were landed, but discards also increased. In summer flounder, most mortality offsetting landings, but due to the smaller weight per discards originate today in the rarity of fish of legal size. Thus, landed fish permitting more fish to be landed per landed weight. most discards are sublegal-size fish. Regulations limiting landings The conundrum probed here is the seeming divergence in out- to larger, heavier fish disproportionately reduce the number of comes of the management program presently in place in the fish anglers bring home because the total allowable catch includes Mid-Atlantic Bight for summer flounder; namely that increasing both landings and discards and is calculated by weight rather than restrictions on catch to limit quota exceedances and maintain number. Larger fish, by weighing much more, count egregiously satisfaction in the fishing experience for the angler may not be towards the weight-based quota. By 2002, recreational discarding simultaneously achievable. The corollary quandary is the loss of was accounting for 60% of all discard mortality by weight (com- the bag limit as an operative management tool, as efforts to restrain mercial + recreational) in summer flounder (Terceiro, 2003) and the landings became increasingly burdensome, thereby placing inordi- number of fish landed per angler-day had dropped to very low nate reliance on the size limit (and season). The study builds upon levels. the observations in Table 1 that suggest that regulatory options The focus on landing of the largest fish to restrain fishing mor- exist that may improve angler satisfaction by permitting anglers to tality also results in the preferential targeting of large females. land more fish, while still restraining fishing mortality by weight Summer flounder females grow faster and live longer than males within allocation constraints. (Poole, 1961; Morse, 1981; Figley, 1977). As a consequence, as sum- To investigate options that might promote increased angler mer flounder grow and age, the survivors are also increasingly gratification and reduce discard mortality without eliciting quota represented by females. Reliance on size limits as the paramount exceedances, we examine, using numerical modeling, a number of restraint on landings perforce produces selective targeting of the alternative management strategies that might (a) bring bag limits largest females and this likely impacts population fecundity. back into the manager’s repertoire, (b) trade discards for landings, Besides the unfortunate commensurate increase in discarding, thereby increasing angler gratification, and (c) provide an increased the steadily increasing size limits ineluctably foster a decrease in number of fish per unit of landings weight, thereby realizing for the angler satisfaction as anglers are forced to release more and more angler a greater number of kept fish. We use as a vehicle for this fish, while returning to the dock with only a few. In 2006, Bochenek study the data proffered by Bochenek et al. (in press) that describe et al. (in press) examined this issue in the New Jersey and New York the fishing experience in the New Jersey and New York party-boat party-boat fishery. In their study, the average angler landed 0.3 fish fishery and which provide empirical observations of several alter- per day, a number too small to conduce gratification in the fishing native management options, namely (1) a reduced minimum legal experience. In 2006, the New Jersey bag limit was set at 8 fish and size; (2) a slot limit in which anglers were allowed to keep a defined the minimum size limit at 16.5 in. Bochenek et al. (in press) docu- fraction of the state-specified bag limit below the state-specified mented clearly that landings were controlled almost exclusively by minimum size limit, and (3) a cumulative-size limit set by con- the size limit. That is, the bag limit was dysfunctional as a manage- flating the state-specified size limit and bag limit to produce a ment tool, although perhaps serving to maintain optimism in the cumulative number of inches of fish legally kept (Table 1). intrepid angler. The high discard mortality rate, the unfortunate focusing of the 2. The model catch on size classes least numerous in the population and the commensurate impact on rebuilding of a robust age-frequency dis- The model carries out a Monte Carlo experiment under defined tribution, the preponderance of females in these largest size classes, fishing conditions, accumulating information, in the simulations and the tendency for larger fish, by weighing more, to facilitate reported herein, on 1000 fishing trips. Information provided to the harvest exceedances strongly argue for the development of new model is of three kinds: (a) metrics describing the fished stock, (b) approaches to reduce discarding and increase landings by number metrics describing the angler community, and (c) metrics defining while still limiting landings by weight. Bochenek et al. (in press) the management strictures restraining landings. evaluated a number of alternative regulatory approaches imposed upon a series of party-boat trips taken out of New York and New 2.1. The fished stock Jersey, pertinent results of which are summarized in Table 1. They found that several alternatives increased landings by number with- The fished stock is defined in terms of its abundance, size out increasing fishing mortality. This occurred because smaller fish frequency, probability of capture, and probability of death upon were landed. Discards were also reduced, however the majority of discard. For the simulations reported herein, abundance was the increase in landings occurred not due to a reduction in discard chosen randomly from a range of abundances defined by a random Author's personal copy

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flounder average smaller in size. The size-frequency distribution used is depicted in Fig. 2. Some sizes of summer flounder are infrequently hooked due to their small size. Thus, size classes were caught based on a defined size-dependent probability of hooking given their encounter. Observations of Bochenek et al. (in press) suggest that fish below 10 in. were rarely hooked. We assume fish above 13 in. were hooked with high probability. To express the size-dependent relationship, we use a hyperbolic tangent function with the probability of hooking of 50% set for fish of 9 in (Fig. 2). Powell et al. (in press) provide observations of injury frequency by size class. For most simulations, we assume that any significant injury ultimately resulted in death. The distribution of size-dependent discard mortality based on this assumption is approximately inverse parabolic, in that fish <14 in. and >16 in. tend to have higher mortality rates (Powell et al., in press)(Fig. 2). Sizes captured, the probability of capture, and the probability of death were assigned by repeated random number draws using Knuth’s Ran1 random number generator (Press et al., 1989). Fig. 1. Fish numbers available for capture for 1000 simulated fishing trips.

2.2. Angler descriptors Poisson deviate (Press et al., 1989). Alternate options using a normal or uniform deviate did not return the variability in catch Anglers were described in three ways: (1) the probability of between trips observed by Bochenek et al. (in press; also compare bringing a fish on deck that encountered the hook, (2) the tendency means and medians in Table 1). Many trips observed by Bochenek to high-grade, and (3) the tendency to illegally fish. For the simula- et al. (in press) caught relatively few fish, but a few trips caught a tions considered here, the latter two were set to zero, as Bochenek much larger number of fish. Thus, the distribution of catch among et al. (in press) found little evidence of high-grading in the summer trips is positively skewed. We assume that the distribution of flounder fishery and illegal fishing was rarely observed. The sim- catch is representative of the distribution of fish abundance and ulations carry this caveat that high-grading, possibly, and illegal availability. An example of fish availability for 1000 simulated fishing, more likely, occur less commonly on observed trips such fishing trips is provided in Fig. 1. Realized catch in the simulated as those carried out by Bochenek et al. (in press); however, the fishing trips is a small fraction of the fish potentially encountered, authors believe that the low frequency observed by Bochenek et al. portrayed in Fig. 1, due to variations in catch efficiency among (in press) are characteristic of party-boat trips targeting summer anglers and variations in the probability of hooking as a function flounder in the Mid-Atlantic Bight. of fish size, as described subsequently. Simulations were run with 20 anglers per trip, a value represen- Simulated vessels fished a stock with a specified size-frequency tative of the trips observed by Bochenek et al. (in press). Bochenek distribution. The size-frequency distribution used was somewhat et al. (in press) examined the distribution of fish caught among modified from that observed in the 2006 NMFS stock survey (NEFSC, anglers on each trip and found that a few anglers were responsible 2006) by slightly enhancing the stock in representatives of the for the bulk of the landings (Fig. 3). That is, the majority of anglers smaller size classes. This was required to provide results represen- were inexperienced and their catch rates were consequently low. tative of those reported by Bochenek et al. (in press), but also makes We defined 10 angler groups, comprising two anglers each on each inherent sense, as the NMFS stock survey includes stations far trip, with catch efficiencies as shown in Fig. 4. This distribution offshore where larger summer flounder are preferentially encoun- imbues the simulated anglers with these critical characteristics: a tered, whereas party-boat trips are biased inshore where summer few account for most of the catch; many leave the trip with few,

Fig. 2. Size frequency of summer flounder available for capture in simulated fishing trips, provided as the fraction of total fish encountered, the probability of capture for each size class, and the probability of death upon discard for each size class from Powell et al. (in press) and modified by limiting mortality in the larger size classes. Author's personal copy

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fied minimum size. For example, the rule might be an 8-fish bag limit with 6 fish larger than 16 in. and 2 fish larger than 14 in., the 14–16 in. slot. (3) A dual-size-limit fishery was defined by a bag limit and both a minimum and a maximum size. In this case, only fish between the two sizes could be landed. (4) Landings were defined in terms of the cumulative size landed. In this case, the simulated angler was permitted to land a number of inches of fish defined as total landings (in cumulative inches)=bag limit × size limit. However, to examine this option comprehensively, we evaluated a series of cumulative-inch quantities relative to a specified size limit that controlled the smallest fish permitted to be added to the cumulative total. (5) A boat limit was defined in addition to a size limit. In this case, the cumulative catch of all participating anglers was applied against a limit for the trip rather than setting a per-angler bag limit.

2.4. Model computational hierarchy

Each simulation began with the choice of an abundance of fish Fig. 3. The relationship between the number of fish caught per angler and the number of anglers catching that number of fish, expressed as cumulative distributions, available to the trip, chosen randomly from a defined Poisson distri- taken from the observations of Bochenek et al. (in press) for a series of party-boat bution. These fish had a defined size frequency and each size class trips that took place in 2006 from ports in New Jersey and New York. Catch data are had a defined probability of addressing a hook given the opportu- summarized in Table 1 for these trips. nity. Each angler on the trip was assumed to have an equivalent opportunity to hook fish; however, the efficiency of each angler and frequently, no fish. This latter characteristic severely damps the modulated the fraction of fish interacting with the hook that were impact of options that increase landings as only a few anglers are successfully hooked and retrieved by the angler. The size and inter- sufficiently skilled to take full advantage of the opportunity. These activity of each fish was defined by a random number draw. few anglers rapidly reach their bag limit, whereas most never do. During the simulation, for each angler, an equivalent number of fish were randomly chosen from the size frequency provided. Of 2.3. Management descriptors these, some were successfully caught. For each of these caught fish, those meeting the specified landing requirements were allocated Five management scenarios were considered. (1) In one case, a to that angler’s landings. The remainder were discarded. Each dis- simple combination of bag-and-size limits was used. In these cases, carded fish was identified as a survivor or a deceased individual a bag limit and size limit were specified for each simulated trip. (2) based on the probability of mortality assigned as a function of fish Slot limits were included by specifying, in addition to the bag limit size. Each decision was based on a random number draw. and size limit, the number of fish permitted to be landed between For simulations reported herein, fish length is converted to a reduced minimum size (the slot minimum size) and the speci- weight using the allometric equation: . Weight (g) = 0.00975 Length (cm)3 125.

Fishing mortality is expressed in pounds and is deﬁned as

F = Landings + Deceased Discards.

Landings are reported in numbers of ﬁsh.

2.5. Model veriﬁcation

The model was verified using observations reported by Bochenek et al. (in press) for the New Jersey 2006-legal bag-and- size limits: namely a bag limit of 8 and a minimum size limit of 16.5 in. Table 2 shows that the median catch for the simulated dataset falls near the mean and somewhat above the median landings per angler from the observed trips. The simulated discard per angler falls between the mean and median of the observations. The high-end tail of the distribution of simulated results also compares favorably with the extreme values of the observations. Thus, the simulated per-angler performance compares favorably with that observed by Bochenek et al. (in press). Powell et al. (in press) reported on the size frequency of discards in the trips observed by Bochenek et al. (in press). The median size discarded was 14.5 in. with an interquartile range of 1.65 in. The simulated distribution of discards shows a median falling between 14 in. and 14.5 in. with an interquartile range encompassing 13–14.5 in., an interquartile Fig. 4. Angler efficiency profile used for simulated fishing trips. Each group of range of about 1.5 in. Thus, the simulated size frequency of dis- anglers was composed of equal numbers of each angler efficiency group. Efficiency defines the probability of hooking and retrieving the fish given an interaction with cards is representative of the size frequency observed. The median the gear. size landed observed by Powell et al. (in press) was 18.1 in. with Author's personal copy

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Table 2 Results of the base case that simulated 1000 party-boat trips under 2006-legal New Jersey management strictures that included a bag limit of 8 and a size limit of 16.5 in.

Mean observed Median observed Median simulated Maximum observed 90th percentile simulated

Landings 0.3 0.2 0.35 1.7 1.95 Discards 3.3 1.8 2.95 21.3 21.20

All numbers are rendered on a per-angler basis. As the number of observed trips was small, the 90 percentile of the simulated trips was compared with the maximum observed trip. Observations were taken from Bochenek et al. (in press), a broader summary of which is provided in Table 1. an interquartile range of 1.53 in. The simulated median was 17.8 in. limit over much of the size-limit range. Increasing the size limit with an interquartile range encompassing 16.5–18 in., about 1.7 in. from 16 in. to 17 in. at a bag limit of 8, for example, lowers fishing These values are also comparable to observations. Thus, the model mortality by a factor of about 1.4. simulated observed fishing trips relatively well. The 2006-legal scenario for New Jersey is identified by a gray We emphasize that the Bochenek et al. (in press) and Powell dot in Fig. 5. Note that the estimated fishing mortality at this point et al. (in press) datasets represent a small fraction of the simu- is about 1.5 lb per angler. Note that the 1.5-lb value remains asso- lated conditions presented herein. In particular, variations in angler ciated with the 16.5 in. size limit over a range of bag limits. Further behavior that might occur under alternative untested regulatory analyses of fishing scenarios will be compared to the 1.5-lb value, conditions have not been examined. The simulations are con- based on the assumption that this level of fishing mortality was rep- strained by the assumption of invariant angler behavior across all resentative of the 2006 year and therefore representative of fishing regulatory options. mortalities that would be necessary to meet quota goals at that time. This level of fishing mortality includes landings that average 3. Results about 0.5 fish per angler over all bag limits above 2 (Fig. 6). Focusing on the value of 1.5 lb per angler for fishing mortality is 3.1. Standard bag-and-size limits consistent with the observations of Bochenek et al. (in press), but 1.5 lb per angler may not be a representative value for the Mid- A series of simulations were run encompassing bag limits from Atlantic Bight as a whole in 2006 and certainly not for other stock 1 to 8 and size limits from 14 in. to 21 in. The range of size limits biomass and consequent quota levels. Summer flounder is on a was chosen to encompass the commercial size limit of 14 in. and rebuilding plan (e.g., Terceiro, 2006) and we can expect that per- the 2008-legal 21 in.-size limit in New York. Bag limits higher than angler landings will increase as the biomass of the stock increases, 8 were not examined as Bochenek et al. (in press) clearly demon- for example. Thus, Fig. 5 and succeeding figures cover a range of strated that the 8-fish bag limit was not a contributing factor to fishing mortalities. For example, in Fig. 5, the bag limit is also inop- minimizing landings. erable at a lower fishing mortality of 1 lb per angler. However, at Summer flounder are managed by weight, but anglers take home 2 lb per angler, bag limits of 3–5 would provide landings near this individual fish. Thus, comparisons of fishing mortality must be target value at lower minimum size limits. made by weight, but comparisons of landings should be made by Fig. 6 shows an approximate 67% increase in fish landed under a number. Fig. 5 shows results of simulations covering a range of bag- 1-fish bag limit with a size limit reduced from 16 in. to 14 in. (from and-size limits in terms of fishing mortality by weight, including 0.3 to 0.5 fish per angler) relative to what might be expected from landings and deceased discards. Fig. 5 demonstrates the ineffec- Fig. 2 that indicates a much larger fraction of fish in the simulated ≥ ≥ tiveness of bag limits in controlling the present-day fishery. Note size frequency at 14 in. compared to 16 in. The weight of fish that fishing mortality specified in terms of weight remains fairly discarded and presumed to die also increases with decreasing bag constant over a range of bag limits from approximately 2–8. In limit, particularly below a bag limit of 3 and size limits lower than comparison, fishing mortality is sensitive to a small change in size 16 in. (Fig. 7). Two factors contribute to this trend and the apparent

Fig. 5. Profiles of fishing mortality (landings + deceased discards) (in pounds: Fig. 6. Profiles of angler landings (in number of fish per angler-trip) for a series of 1 kg = 2.2 lb) for a series of bag limits and minimum size limits. The 2006-regulated bag limits and minimum size limits. The 2006 case for New Jersey, an 8-fish bag fishery in New Jersey, an 8-fish bag limit with a size limit restriction at 16.5 in., as limit with a size limit restriction at 16.5 in., as simulated, marked by a gray dot, is simulated, is marked by a gray dot. associated with a fishing mortality of 1.5-lb per angler-trip (Fig. 5). Author's personal copy

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Fig. 7. Profiles of fishing mortality due solely to the death of discards (in pounds: Fig. 8. Profiles of the difference in fishing mortality (landings + death by discards) (in 1 kg = 2.2 lb) for a series of bag limits and minimum size limits. The 2006 case for New pounds: 1 kg = 2.2 lb) between a simple series of bag limits and minimum size limits Jersey, an 8-fish bag limit with a size limit restriction at 16.5 in., as simulated, marked and the case for a dual-size limit with an upper size limit of 20 in. The trajectory for by a gray dot, is associated with a total fishing mortality of 1.5-lb per angler-trip (Fig. a fishing mortality of 1.5-lb per angler per trip, under standard bag-and-size limit 5). configurations (Fig. 5), is indicated by the gray line. Difference is computed as D (plotted value)=dual-size limit value − standard bag-and-size limit value. conflict between the change in fish landed shown in Fig. 6 and the dual-size-limit scenario (Fig. 8). Angler landings are little changed change in fish abundance shown in Fig. 2. (a) Fishermen are pre- (Fig. 9). Although large fish, now discarded, weigh more, they exist sumed to continue to fish for other species after their bag limit is in the population in numbers too few (Fig. 2) for their discard to met, thus increasing the number of discarded fish when bag limits realize a measurable increase in the landings of smaller, less heavy are low as observed in Fig. 7 at bag limits below 3, but (b) this trend fish. Note that the gray line in Fig. 9, traversing the 1.5-lb trajectory, is strongest for bag-and-size-limit combinations for which the bag follows the 0.5 fish per angler curve over most bag limits, as was limit influences landings. Thus, above about 16.5 in., size limit dom- the case with the standard bag-and-size-limit configuration (Fig. 6). inates landings and thus, discard mortality. At a size limit of 16.5 in., Thus neither fishing mortality nor realized landings are improved about 0.30–0.325 lb of discarded fish would be expected to die per by this dual-size limit. fishing trip. In fact, the weight of fish discarded and presumed to An alternative in which the upper size limit was reduced to die increases rapidly with increasing size limit, as would be antic- 18 in. returned somewhat improved results (Fig. 10). In this case ipated by the necessity of discarding an increasingly large fraction fishing mortality declines over nearly all bag-and-size limits rela- of caught fish (Fig. 7). The rate of increase, however, is small relative tive to the standard bag-and-size-limit configuration. The decline to the rate of decrease in total fishing mortality (Fig. 5) for the same is sufficient to shift the 1.5-lb target fishing mortality lower on the change in size limit because a relatively low rate of discard mor- size-limit axis (y-axis in Fig. 10), thus permitting access of fish- tality exists in summer flounder (Fig. 2). Nevertheless, at low bag limits and low size limits, the average landings per angler increase only incrementally relative to the much larger number of fish available for capture. This outcome is dictated by the larger number of fish discarded at the lower bag limit and the relative inefficiency of the angling corps participating that still results in a goodly number of anglers leaving the trip without any fish (Figs. 3 and 4). Thus, the increment in landings anticipated by the increased abundance of smaller fish in the size-frequency distribution (Fig. 2) is not fully realized. At low bag limits, the lowered size limit permits the few skilled anglers present on each trip to reach their bag limit, but landings of the unskilled anglers are little changed.

3.2. Dual-size limits

In these simulations, a definitive upper and lower size limit required landings to be limited to an intermediate size range of fish. We set the upper size limit to 18 in. in some simulations and to 20 in. in others and varied the lower size limit down to 14 in. Set- ting the upper size limit at 20 in. does little to influence landings or fishing mortality relative to the standard bag-and-size-limit configuration (Fig. 8). Note that fishing mortality rarely varies between Fig. 9. Profiles of angler landings (in fish per angler-trip) for the case of a dual-size the two options by more than 0.1 lb per angler-trip along the 1.5- limit with an upper size limit of 20 in. and a range of lower size limits. The trajectory for a fishing mortality of 1.5-lb per angler-trip (about 0.5 fish landed per angler-trip), lb target line defined in Fig. 5, although, over most of the range of under standard bag-and-size limit configurations (Fig. 5), is indicated by the gray bag-and-size limits tested, fishing mortality trends lower with the line. Author's personal copy

E.N. Powell et al. / Fisheries Research 105 (2010) 215–227 221

Fig. 10. Profiles of the difference in fishing mortality (landings + death by discards) Fig. 12. Profiles of discard mortality (in pounds: 1 kg = 2.2 lb) for a dual-size limit (in pounds: 1 kg = 2.2 lb) between a simple series of bag limits and minimum size with an upper size limit of 18 in. and a range of lower size limits. The trajectory limits and the case for a dual-size limit with an upper size limit of 18 in. The trajectory for a fishing mortality of 1.5-lb per angler-trip, under standard bag-and-size limit for a fishing mortality of 1.5-lb per angler-trip, under standard bag-and-size limit configurations (Fig. 5), is indicated by the gray line. The equivalent trajectory for the configurations (Fig. 5), is indicated by the gray line. The equivalent trajectory for the 18 in. dual-size limit is indicated by the dashed gray line. 18 in. dual-size limit is indicated by the dashed gray line. Difference is computed as D (plotted value)=dual-size limit value − standard bag-and-size-limit value. only marginally counterweighed by the smaller fish landed and, so, no longer discarded. Thus, increased landings occur, but with only ermen to a larger range of smaller fish while restricting access to a minor decrease in discard mortality. a larger range of larger fish. Angler landings at 1.5-lb-per-angler Fig. 11 also shows the case for a 2-lb-per-angler target. In this fishing mortality accordingly rise, by about a factor of 1.25, and at a case, in comparison to the simulation of standard bag-and-size lim- lower size limit of 16 in. (Fig. 11). Thus, the change in maximum its in Fig. 6, angler landings diverge little at high bag limits, but size permits a lowering of the lower size limit, while increas- the dual-size limit improves angler landings considerably at inter- ing landings measured in numbers of fish. Yet, at the same time, mediate bag limits converging on 5. Intermediate bag limits also total fishing mortality as measured in fish weight declines for a enhance the differential in landings between the dual-size limit given bag-limit and lower size-limit combination. This is accom- and the standard bag-and-size limit at the 1.5-lb-per-angler target, plished because the landed fish are smaller, not because discard converging in this case on 3. Each originates in the earlier capture mortality averages lower (Fig. 12). Note in Fig. 12 that the dual-size of small fish and the assumption of no high-grading. An increasing limit reduced discard mortality from about 0.35 lb to no more than tendency to high-grade, of course, would morph the dual-size-limit 0.325 lb because some larger fish are presumed to die, but these are approach into the standard bag-and-size-limit approach. Bochenek et al. (in press) observed little high-grading in cases with reduced size limits, but the representativeness of this observation remains unevaluated.

3.3. Slot limits

In this case, we allowed two fish to be landed between 14 in. and the given size limit that varied between 15 in. and 21 in. As the size limit increased, the size range of the slot also increased. For this option, both bag-and-size limits exert limitations on fishing mortality over a range of bag-and-size limits (Fig. 13), unlike the case observed for the standard bag-and-size-limit configuration where the bag limit was relatively dysfunctional over a wide range of bag limits (Fig. 5). The exception is bag limits below 3, wherein the bag limit alone controls fishing mortality (Fig. 13). The cause of the latter is the use of a two-fish slot limit, so that bag limits less than 3 have no size limit other than the slot limit size. Regardless of the more balanced role of bag limits and size limits over a wide range of both, no functional bag-and-size-limit com-

Fig. 11. Profiles of angler landings (in fish per angler-trip) for a dual-size limit that bination remains viable in comparison to the 1.5-lb comparator required discard of fish ≥18 in. The trajectory for a fishing mortality of 1.5-lb per defined in Fig. 5 as the practical limit to removals under the 2006 angler-trip (about 0.5 fish landed per angler-trip over much of the bag-limit range), quota system (Fig. 13). Fishing mortality is substantially increased under standard bag-and-size limit configurations (Fig. 5), is indicated by the gray over all bag limits along this trajectory and, indeed, exceeds 1.5 lb line. The equivalent trajectory for the 18 in. dual slot limit is indicated by the dashed per angler over all size limit-bag limit combinations except at gray line. The equivalent trajectories for fishing mortalities of 2-lb per angler-trip are shown as the narrow dotted line (standard bag-and-size limit) and the wide bag limits of two or less. We emphasize again that this inference dotted line (dual-size limit). remains relative to the assumption of representativeness for the Author's personal copy

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Fig. 13. Profiles of fishing mortality (landings + death by discards) (in pounds: Fig. 15. Profiles of angler landings (in fish per angler-trip) for a slot limit permitting 1 kg = 2.2 lb) for a slot limit in which keeping two fish between 14 in. and the speci- the take of 1 fish between 14 in. and the specified size limit. The trajectory for a fied size limit was allowed. The trajectory for a fishing mortality of 1.5-lb per angler fishing mortality of 1.5-lb per angler-trip (about 0.5 fish landed per angler-trip over per trip, under standard bag-and-size limit configurations (Fig. 5), is indicated by much of the bag-limit range), under standard bag-and-size limit configurations (Fig. the gray line. 5), is indicated by the gray line. The equivalent trajectory for the slot limit (Fig. 14) is indicated by the dashed gray line. Thus, a higher size limit is required to generate the same fishing mortality (1.5 lb per angler-trip). The standard bag-and-size limit Bochenek et al. (in press) set of observations from which the 1.5-lb with the slot limit added would result in about 0.9 fish landed per angler-trip, but target value is inferred. a fishing mortality of 2.1 lb per angler (Fig. 14), well above the 1.5 lb per angler-trip Dropping the bag limit for the slot limit to 1 fish reduces total comparator. The equivalent trajectories for fishing mortalities of 2-lb per angler- fishing mortality nearer to, but still above that observed in Fig. 5 trip are shown as the wide dotted line (standard bag-and-size limit) and the narrow dotted line (slot limit). (Fig. 14). In this case, however, the 1.5-lb target falls at a rational size limit of about 17.5 in. from bag limits of 2–8 (Fig. 14). level into balance with Fig. 5 (Fig. 14), but still raises angler landings Comparison of landings by number (Fig. 15) with standard bag- above the 0.5 fish per angler-trip characteristic of the standard bag- and-size limits (Fig. 6) shows that landings by number increased and-size-limit configuration (Fig. 15). by a factor of about 1.25 from 0.5 fish per angler realized under A higher target for fishing mortality of 2-lb-per-angler (Fig. 14) standard bag-and-size-limit configurations to 0.625 fish per angler results in a limited change in landings number. The 2-lb-per-angler for a 1.5-lb level of fishing mortality, but only if the size limit is fishing-mortality line follows relatively closely the 1-fish-landed- raised to about 17.5 in. This follows observations of Bochenek et per-angler line for the 1-fish slot limit (Fig. 15) and also for the al. (in press) that use of a slot limit increases landings by number standard bag-and-size limit (Figs. 5 and 6). Thus, the slot-limit relative to fishing mortality by weight (Table 1). Raising the size option is increasingly effective relative to standard bag-and-size limit to 17.5 in. under a slot limit of 1 brings the fishing mortality limits as the target limit on fishing mortality is lowered and the size limit becomes increasingly the dominant controller of landings. Both for the 1.5-lb and 2-lb fishing-mortality targets, the minimum size limit, exclusive of the slot, for the one-fish slot limit (Fig. 15) is considerably above that for the standard bag-and-size limit. For the 1.5-lb target, the minimum size limit falls between 17.5 in. and 18 in. relative to 16.5 in. for the standard bag-and-size- limit. The equivalent levels for the 2-lb target are about 16.5 in. and 15.5 in. (Fig. 15). Thus, improved landings by number under the slot limit come at the price of an increased size limit for the remainder of the bag limit. Note that discard mortality remains relatively constant across most bag limits with a 17.5 in. size limit (Fig. 16) and that this value trends higher than the standard bag-and-size-limit combination (Fig. 7) for the same fishing mortality. The size limit restrains catch over much of this range, while the slot limit permits an increase in total landings. A comparison to Fig. 7 shows that discard mortality has increased along with landings by number while fishing mortality has remained stable over most bag limits, for the target fishing mortality of 1.5-lb per angler. Thus the slot limit increases angler take not by limiting discard mortality overall, but by reducing the weight of landings relative to the number. Why? If anglers Fig. 14. Profiles of fishing mortality (landings + death by discards) (in pounds: retain slot-sized animals without high-grading, an assumption of 1 kg = 2.2 lb) for the case of a slot limit in which 1 fish could be landed between this simulation, then some larger fish are discarded that otherwise 14 in. and the specified size limit. The trajectory for a fishing mortality of 1.5-lb per angler-trip, under standard bag-and-size limit configurations (Fig. 5), is indicated would be landed and discard mortality consequently marginally by the gray line. increases. Author's personal copy

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Fig. 16. Profiles of discard mortality (in pounds: 1 kg = 2.2 lb) for an optional slot Fig. 18. Profiles of angler landings (in fish per angler-trip) for a boat limit of 20–160 limit in which one fish between 14 in. and the specified size limit is allowed. The fish per trip with a specified size limit. The trajectory for a fishing mortality of 1.5- trajectory for a fishing mortality of 1.5-lb per angler-trip for the optional slot limit lb per angler per trip, under standard bag-and-size-limit configurations (Fig. 5), is (Fig. 14) is indicated by the gray line. indicated by the gray line. The equivalent trajectory for the boat limit (Fig. 17)is indicated by the dashed gray line. Note that the standard bag-and-size-limit x-axis of Fig. 5 is equivalent to the x-axis on this plot for 20 anglers (e.g., 8 fish per angler × 20 3.4. Boat limit anglers = 160 total).

Party-boat trips might be operated under a boat limit, rather than a limit for individual anglers. We varied the boat limit from 20 to 160 fish per 20 anglers (equivalent to 1–8 fish per angler). Fishing occurs only at the lowest boat limit, equivalent to 1 fish per angler mortality for a size limit of 16.5 in. was relatively equivalent for this (Fig. 18), where some efficient anglers were able to land more than scenario to the standard bag-and-size-limit configuration, except 1 fish and thus offset the overall reduction in landings anticipated at low boat limits (Fig. 17). That is, fishing mortality remained by a 1-fish bag limit. high even at low boat limits. In this scenario, efficient anglers were able to catch more than 8 fish, the upper standard bag limit used in previous simulations, and these anglers’ proficiency dominated 3.5. Cumulative-size limit landings at a given size limit. As in the case of standard size limits, for most bag (boat) limits, the number of fish above the minimum Cumulative-size limits using a minimum size above 16 in. did size primarily controlled catch. The positive influence on landings, not return a per-angler landing rate higher than standard bag- beyond the landings expected from bag-and-size-limit controls, and-size limits. Consequently, simulations focused on size limits of 14–16 in. Setting a lower size limit at 16 in. and using a cumulative- size limit to restrain landings in place of a bag limit results in a range of de facto bag-and-size limits yielding a fishing mortality of ≤1.5 lb per angler (Fig. 19). De facto bag limits above 3 result in fishing mortality rates above this target level across all de facto size limits. Thus, maximum landings allowed within the 1.5-lb target value include combinations ranging from 2 fish × 21 in. (42 in.) to 3 fish × 16 in. (48 in.) to 3 fish × 18 in. (54 in.). Angler landings under a cumulative-size limit with a lower size limit specified at 16 in. identify a series of bag-and-size limit products yielding landings above 0.5 fish per angler, with typical increases, still below the 1.5- lb fishing mortality limitation, of a factor of 1.10, raising landings to 0.55 fish per angler (Fig. 20). If a lower specified minimum size limit of 14 in. is used, the 1.5- lb target line falls at bag-and-size-limit products distinctly lower than for the 16 in. specified minimum size limit (Fig. 21). De facto bag limits above two produce a level of fishing mortality above the 1.5-lb target value. Landings per angler, however, are much improved with maximum values reaching 0.8 fish per angler, an improvement over the standard bag-and-size limit configuration of a factor of 1.6 (compare Figs. 6 and 22). This increase is consis- Fig. 17. Profiles of fishing mortality (landings + death by discards) (in pounds: tent with observations (Table 1). One cannot overemphasize the 1 kg = 2.2 lb) for the case of a boat limit and a specified size limit. The trajectory increase in angler landings relative to fishing mortality resolved by for a fishing mortality of 1.5-lb per angler-trip, under standard bag-and-size-limit this fishing scenario. Lesser improvements occur at higher fishing- configurations (Fig. 5), is indicated by the gray line. Note that the standard bag-and- mortality targets. At the 2-lb-per-angler target, for example, the size-limit x-axis of Fig. 5 is equivalent to the x-axis on this plot for 20 anglers (e.g., 8 fish per angler × 20 anglers = 160 total). degree of improvement drops to a factor of 1.2. Author's personal copy

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Fig. 19. Profiles of fishing mortality (landings + death by discards) (in pounds: Fig. 21. Profiles of fishing mortality (landings + death by discards) (in pounds: 1 kg = 2.2 lb) for the case of a cumulative-size limit under a specified minimum size 1 kg = 2.2 lb) for the case of a cumulative-size limit under a specified minimum size limit of 16 in. Bag × size combinations for size limits below 16 in. (as differentiated limit of 14 in. The 1.5-lb fishing mortality trajectory for the case of a 16 in. specified by the dotted line) are undefined, from one point of view, in this fishing scenario, size limit (Fig. 19) is shown by the dashed gray line. although the total-inches value thereby derived could be used in regulation; hence these options are included in the reported set of simulations. among fish of larger size. As a number of fishing options examined here vary the discard rate of large fish, the upward trend in the 3.6. Sensitivity to fish metric parameterization anticipated probability of discard mortality might influence simulation outcomes. Consequently, we examined the influence of this Most fish metrics used to parameterize the model can be trend by running simulations in which such a trend did not exist expected to vary by location and year. Different populations will (Fig. 2). Among the various fishing options, cases in which the larger have different abundances and size frequencies. Our choice for fish were discarded under a dual-size-limit rule would be most these metrics (Fig. 2) was based on same-year survey information affected by the choice for the probability of discard mortality for plus tuning to field observations used for verification of simulated large fish. Hence, we focused on the simulations reported in Fig. 10 outcomes (Figs. 5–7, Table 2). Results of model simulations, obvi- in which a dual-size limit was applied with an upper size limit of ously, will vary as these population characteristics vary. However, 18 in., but with the modified, and lower, probability of discard mor- the probability of mortality upon discard has been imposed based tality as shown in Fig. 2. The results show only a minor change on data reported by Powell et al. (in press). This relationship is in fishing mortality due to a change in discard mortality of larger curvilinear (Fig. 2) with lowest discard mortality in medium-sized fish across all bag-and-size-limit configurations (Fig. 23). Hence, fish and, importantly, a trend towards higher discard mortality we conclude that the model simulations considered in Figs. 5–22 are not significantly affected by the uncertainty of mortality rate

Fig. 20. Profiles of angler landings (in fish per angler-trip) for the case of a cumulative-size limit under a specified minimum size limit of 16 in. Bag × size combinations for size limits below 16 in. (as differentiated by the dotted line) are Fig. 22. Profiles of angler landings (in fish per angler-trip) for the case of a undefined, from one point of view, in this fishing scenario, although the total-inches cumulative-size limit under a specified minimum size limit of 14 in. The location of value thereby derived could be used in regulation; hence these options are included the 1.5-lb fishing mortality line for the 16 in. minimum size limit (Fig. 19) is shown in the reported set of simulations. The location of the 1.5-lb fishing mortality line by the gray dotted line. The location of the 1.5-lb fishing mortality line for the 14 in. (Fig. 19) is shown by the gray dashed line. minimum size limit (Fig. 21) is shown by the gray dashed line. Author's personal copy

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assumed that the fishing mortality levels reported by Bochenek et al. (in press) were representative of the levels necessary to meet 2006 quota goals. Thus, we compare alternatives to a target fishing mortality of 1.5-lb-per-angler. Obviously, alternative choices would provide differential comparisons in the simulations reported here. We investigate neither the impact of the choice of population metrics nor a range of target fishing mortalities, as our desire is to compare alternative approaches to managing the summer flounder fishery under a specified quota goal and set of stock characteristics. We do provide, however, information pertinent to a range of other quota goals for the defined set of stock characteristics for comparison. In addition, we do evaluate the potentially important choice of the probability of discard mortality of larger fish, as the size dependency of mortality, being curvilinear, is perhaps surpris- ing. This choice, however, did not materially affect the outcome of simulations reported here.

4.2. Trends in landings

We examined a series of different management options. These Fig. 23. Profiles of discard mortality (in pounds: 1 kg = 2.2 lb) for a dual-size-limit case that required discard of fish ≥18 in., but using a modified, and lower, probability included the standard approach of setting independent bag-and- of discard mortality for larger fish (Fig. 2). The trajectory for a fishing mortality of size limits, the use of dual-size limits, slot sizes, a boat rather than 1.5 lb per angler-trip, under the unmodified probability of discard mortality (Fig. 10) per-angler bag limit, and a cumulative-size limit. Simulations of is shown as the gray dashed line. fishing trips constrained by standard bag-and-size limits confirmed observations by Bochenek et al. (in press) that the bag limit was of large fish upon discard relative to fish of intermediate size relatively ineffective in controlling fishing mortality in 2006. A bag classes. limit of 8 fish simply serves to maintain optimism in the angler. Landings are controlled almost exclusively by the minimum size 4. Discussion limit. Per-angler landings average only about 0.5 fish per trip, in comparison to the 8 fish permitted. Re-installation of a functional 4.1. Perspective bag limit effective in controlling landings would require bag limits no higher than 1. Although speculative, a bag limit this low likely Managers of the recreational fishing industry face two often would discourage fishing, even if, in the mean, it did not substan- divergent challenges. First and foremost is the need to restrain land- tively modify realized angler landings in comparison to the 8-fish ings within specified limits to achieve quota goals. The tendency in limit in force in 2006. meeting such goals has been to use classic bag-and-size-limit com- One mechanism to bring bag limits into force to limit landings binations, with increasing reliance on size limits as the primary might be boat limits. This would permit individual anglers to bring control as the number of fish available to the angler increased. home a number of fish, thereby maintaining optimism in the fishing But, besides this goal, managers also should consider maximiz- experience, but effectively control catch. Unfortunately, boat limits ing the fishing experience within a specified total allowable catch. do not become effective unless the per-angler equivalent drops to Standard bag-and-size limits demonstrably do not optimize this 1 fish or less. Thus low, and likely unacceptably low, boat limits objective (Bochenek et al., in press). Accordingly, we examine alter- would be required. One reason for the limited impact of boat limits native fishing scenarios that might improve the angling experience is the distribution of angler efficiency. A few anglers account for without jeopardizing quota goals. We define angler satisfaction in most of the fish caught (Fig. 3) and these anglers’ catches are less terms of fish landed, as the summer flounder fishery is demonstra- restrained under a boat limit than under a per-angler bag limit, thus bly a consumptive fishery and interviewed anglers emphasize the insulating the total catch from a per-angler-equivalent decrease in desirability of landing more fish (our unpubl. data). One way to bag limit inferred from a lowering of the boat limit. tackle this shortcoming is to transfer some exploitation to smaller The remaining alternatives address management through fish, thereby increasing the number of fish landed without increas- creative modifications of standard bag-and-size limits. Implemen- ing the fishing mortality as measured by weight. tation of these would require that bag limits be added to the We have evaluated a range of options without regard to the repertoire of functional controls on landings, however, and this practical feasibility of implementation through regulation and represents a constraint. Each of the options investigated seeks to enforcement. We believe that regulatory options that might be suf- increase the landing of smaller less heavy fish, thereby increas- ficiently responsive to the dual needs of limiting landings while ing landings by number while not increasing fishing mortality by encouraging angler participation and thus which may merit the weight. difficulty of implementation upon rigorous contemplation will rise One option is a dual-size limit in which both a minimum and in the manager’s esteem over time. Thus, a wide range of options maximum size limit is specified, such that only fish between these should be evaluated initially without constraint by a cursory eval- two sizes are permitted to be landed. Setting the upper limit to uation of practicability of enforcement. 20 in. has little effect on realized landings per angler when fishing The model is configured to produce results representative of mortality is constrained to 1.5 lb per angler. In our simulated size observations of the New Jersey and New York party-boat fish- frequency (Fig. 2), too few fish are this large and so their return ery in 2006 as reported by Bochenek et al. (in press). In order to to the sea does not materially affect the number of landed fish. accomplish this, a number of population parameters were spec- However, if the upper limit is set to a lower value, 18 in. in our sim- ified, including the size frequency, abundance, and variance in ulations, the outcome is much changed. In this case, angler landings abundance. The outcomes of simulations reported herein obviously increase significantly over a wide range of bag limits without mate- are substantively dependent upon these choices. In addition, we rially changing total fishing mortality. Furthermore, a lowering of Author's personal copy

226 E.N. Powell et al. / Fisheries Research 105 (2010) 215–227 the bag limit to 3–4 fish would permit also a lowering of the size part permit increased landings relative to discards and this moves limit to 16 in. One important outcome of this option, then, is to rein- discard mortality to landings, a useful outcome. However, the prob- state a functional bag limit without requiring a bag limit too low, ability of mortality due to discarding is low in summer flounder perhaps, to discourage angling. exceeding about 13 in. (Powell et al., in press) and thus relatively The dual-size limit offers one way to increase landings, little gain occurs in simply minimizing discards. Rather, successful but at the expense of the luxury of landing the largest fish. management options are those that permit effort to be transfered However, as the largest fish are almost exclusively female from larger fish to smaller fish, thus reducing total weight landed (Figley, 1977; Smith and Daiber, 1977; Morse, 1981), the dual-size relative to total number. limit does permit transfer of fishing effort to the smaller male con- In a consumptive fishery, the ability to land more fish by number tingent. In summer flounder, males grow slower and suffer a higher may be perceived as an improved fishing experience by the angler. natural mortality rate (Poole, 1961; Morse, 1981; NEFSC, 2008). As At the same time, for summer flounder, transfer of effort to interme- a consequence, the sex ratio becomes increasingly biased towards diate size classes results in the increased landing of males, thereby females as size increases. High minimum size limits focus fishing retaining in the population a larger number of large females and mortality preferentially on large females, a dubious outcome for thus enhancing potential population fecundity. Thus, the imple- retaining sustainability in the stock. Thus, any transfer of effort to mentation of such options, while improving angler satisfaction, the males, more common in the intermediate size classes, is likely may also meet biological goals for the stock. to be beneficial to sustaining the fishery and the stock. Today’s management approach emphasizes standard bag-and- Slot limits permit the taking of a few smaller fish, while still size limits. Bag limits are set high to retain angler optimism, but allowing landing of large fish. A two-fish slot limit increases fish- are not functional in restricting landings. Size limits are retained ing mortality above target levels across essentially all bag limits high to restrict landings. The approach does not maximize the and for all size limits and so is not a management alternative if a number of landed fish under a fishing mortality restriction. The 1.5-lb-per-angler target is desired. The one-fish slot limit, however, approach emphasizes the landing of large females to the detriment performs as well as the 18 in. dual-size limit in increasing landings of the stock’s potential fecundity. Thus, creative options that bring under a fishing mortality constraint of 1.5 lb per angler, and land- into play a functional bag limit and which permit landing of more ings increase to about the same degree. At the same time, anglers smaller fish offer useful attributes and should become part of the are not precluded from taking the largest fish. Bochenek et al. (in management portfolio of options for simultaneously developing a press), in a field test of several alternative management scenarios, sustainable stock and a sustainable recreational fishery. identified the slot limit as a preferred option, as it was shown to per- Comparing all fishery options reveals that slot, dual-size, and mit increased landings without increasing total fishing mortality. cumulative-size limit options provide these services. Slot limits and Our simulations are in agreement with these empirical data. dual-size limits improve landings relative to fishing mortality, but Bochenek et al. (in press) also tested a cumulative-size sce- the cumulative-size limit outperforms both by a substantial degree. nario in which anglers were allowed to land a cumulative number The purport of simulations comparing a range of options empha- of inches of fish, under a minimum size-limit restriction. They sizes the value of adding cumulative-size limits to the managers’ reported that this approach performed better than a slot limit in repertoire to restrain the impact of steadily increasing size limits permitting increased landings under a fishing mortality restriction on angler satisfaction while decreasing discards and reducing the (Table 1). We examined two cases. In one, the minimum size limit mortality of large females. was set at 16 in. In this case, landings could be increased by a factor of about 1.25 over a range of cumulative-size limits that encom- passed de facto bag limits of 1–3 and size limits of 16–21 in. Even Acknowledgments better was a cumulative-size limit under a minimum size restriction of 14 in. In this case, angler landings increased by a factor of This study was funded by the Mid-Atlantic Fisheries Manage- 1.6 over a range of de facto bag limits of 1–2 and a wide size-limit ment Council Research Set-aside Program using the donations range. of quota from recreational and commercial fisheries. We thank Comparing all alternatives, the cumulative-size limit clearly the National Fisheries Institute Scientific Monitoring Committee outperformed other options. Setting a minimum size limit to 14 in. for handling the exempted fishery that converted allocated quota increased total landings by a greater margin than all other man- into financial support for this research program. Fish quota was agement options. Of note, however, is the necessary reliance on caught by vessels from Virginia to Massachusetts. We appre- low de facto bag limits. It is ironic that the highest landings occur ciate the efforts of the many fishing vessels involved in this under conditions that might lower fishing interest by appearing to endeavor. restrict landings. Thus, highest landings by number occur under a cumulative-size limit of about 30 in. of fish. A tradeoff may, there- References fore, exist between angler perception of possible fishing success and angler realized fishing success, in that management options Bochenek, E.A., Powell, E.N., DePersenaire, J., in press. Evaluating catch, effort, and maximizing the latter may not satisfy the former. bag limits on summer flounder directed trips in the recreational summer flounder party boat fishery. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science Journal. Figley, W., 1977. Sex Ratios Within Length Groups of Commercially Caught Summer 5. Conclusions Flounder in New Jersey. N. J. Tech. Rpt. No. 20M. NJDEP, Division of Fish, Game and Shellfisheries, Bureau of Fisheries, 16 pp. Morse, W.W., 1981. Reproduction of the summer flounder, Paralichthys dentatus (L.). We examine creative management options for the summer J. Fish Biol. 19, 189–203. flounder fishery to determine if angler satisfaction, as measured NEFSC, 2000. 31st Northeast Regional Stock Assessment Workshop (31st SAW) Pub- by the number of fish landed, can be increased without creating lic Review Workshop, NEFSC Ref. Doc. 00-14, 45 pp. NEFSC, 2008. 47th Northeast Regional Stock Assessment Workshop (47th SAW) quota exceedances. We employ a model parameterized for the Assessment Report & Appendixes, NEFSC Ref. Doc. CRD 08-12, 2,097 pp. party-boat fishery. Whether such parameterizations can be reliably Poole, J.C., 1961. Age and growth of the fluke in Great South Bay and their significance transferred to other recreational fishery sectors is unknown. Nev- to the sport fishery. N. Y. Fish Game J. 8, 1–18. Powell, E.N., Bochenek, E.A., DePersenaire, J., King S.E., in press. Injury frequency for ertheless, results of simulations suggest that improved regulatory discarded summer flounder (Paralichthys dentatus) in the recreational fishery of options exist relative to standard bag-and-size limits. The options in the Mid-Atlantic Bight: influence of landing size regulations. Author's personal copy

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Press, W.H., Flannery, B.P., Teukolsky, S.A., Vetterling, W.T., 1989. Numerical Recipes. Terceiro, M., 2003. Stock Assessment of Summer Flounder for 2003, NEFSC Ref. Doc. Cambridge University Press, Cambridge, 702 pp. 03-09, 179 pp. Smith, R.A., Daiber, F.C., 1977. Biology of the summer ﬂounder. Paralichthys dentatus Terceiro, M., 2006. Stock Assessment of Summer Flounder for 2006, NEFSC Ref. Doc. in the Delaware Bay. Fish. Bull. 75, 823–830. 06-17, 119 pp. Terceiro, M., 2002. The summer ﬂounder chronicles: science, politics, and litigation, 1975–2000. Rev. Fish Biol. Fish. 11, 125–168.