A. Brief Project Overview:
The Science Consortium For Ocean Replenishment And Enhancement (SCORE) is a science-based approach to stocking hatchery-reared marine organisms to help rebuild depleted marine fisheries (marine fisheries enhancement). SCORE scientists are conducting research to resolve critical uncertainties about the effectiveness of culture-based marine enhancement as a fishery management tool. It is anticipated that significant progress will be made in the next five years, leading to greater and greater success from marine enhancement programs in the U.S.

As scientific gains are made in understanding the potential, SCORE scientists are partnering with NMFS and regional fishery-management agencies to develop policy and apply fishery-enhancement science to rebuilding depleted coastal stocks. Linkages with local fishing communities provide the cadre of citizens needed to support and expand enhancement as a fishery management strategy. Much of the enhancement technology developed here will be supported by funds generated by contributions and license fees paid by stakeholders and user groups. To fully embrace and use the marine enhancement concept, demonstrated success stories are needed in a few key states. SCORE research is planned and coordinated to achieve such successes. Built around the principles of a responsible approach to marine stock enhancement (Blankenship and Leber; and see Leber, 2002), SCORE scientists are conducting key experiments to resolve critical uncertainties about how to control the biological, ecological, and economic effectiveness of marine fisheries enhancement.

SCORE is an R&D initiative conducted by a consortium of national partners. It is a powerful alliance of scientists and fishery managers currently working in the field of marine stock enhancement in the U.S.A., which encourages improved utilization of their expertise and resources. Bringing these scientists and managers together through SCORE allows synergisms to develop that would not occur otherwise.

This contract commenced in September, 2001. This interim report covers progress made during the period January 1, 2003 through June 30, 2003.

B. Project Accomplishments:
a. Tasks scheduled for this period
i. Develop snook-aquaculture production technology
ii. Develop optimal stocking strategies for snook
iii. Evaluate the effectiveness of snook enhancement
iv. Produce winter flounder and prepare for summer 2003 release-recapture experiments
v. Develop marine fish culture policy

b. Tasks accomplished this period:
i. Develop snook aquaculture production technology (Primary responsibility: Mote Marine Laboratory)
Advances in common snook aquaculture technology are needed to provide juvenile snook for the stock enhancement research conducted by Mote Marine Laboratory’s (MML) Center for Fisheries Enhancement.

Preparation for 2003 Snook Production Efforts
The preparation for the 2003 snook production season began with planning experimental research goals and the construction of tank systems. A light and temperature controlled broodstock holding facility was constructed at MML and two of the four broodstock tanks (17,385 liter) are designated for snook. We transferred wild snook broodstock from the Mote aquarium to these systems and collected additional broodstock in February. Each broodstock holding system has been equipped with a bead filter for solids filtration, a fluidized bed for biofiltration, a UV unit, and a heater/chiller to control temperature. Construction of the experimental larval rearing system was completed and is ready for the larval production effort in the spring. There are three 4-tank systems and two of the systems (four 114-liter tanks) are available for the snook studies. In the larval rearing systems, solids will be trapped in the sump using floss, biofiltration will occur in the fluidized bed. These systems also include a UV unit and a protein skimmer. A juvenile experimental system is currently being designed, and construction will begin in April.
In both the 2001 and the 2002 season, we experienced a high incidence of lordosis in cultured snook stocks. During 2002, a number of experiments were performed to determine the cause and possible reduction of the incidence of lordosis in the early larval development stages. Experiments were designed to investigate both environmental, as well as, nutritional variables that could influence the frequency of lordosis among cultured fish. Because of the poor egg quality in 2002, not enough larvae were produced for the desired number of experimental replicates. Therefore, research plans were made to determine the cause of lordosis in larval snook in the 2003 production season.
Lordosis experienced in 2002 was thought to be a nutritional problem occurring in later juvenile stages, rather than early larval stages (as in 2001). This theory was briefly examined with the snook juveniles cultured in 2002. Nutritional profiles and pathological analyses of lordotic and wild-caught normal fish are underway. Further nutritional studies are planned for 2003.

2003 Snook Production Efforts to Date
The two snook broodstock tanks have been stocked with 13 fish per tank (5 females and 8 males in tank # 1 and 4 females and 9 males in tank # 2). We are acclimating the fish to the natural spring/early summer photoperiod and temperature conditions.

In mid April 2003 we began sampling snook stocks at known natural spawning sites to determine spawning readiness. Spawning trips have been scheduled over a 5-day period around the full and new moon cycles from April through August. The first successful collection of snook was on days 3 and 4 after the new moon in early May; however, these fish were not ready to spawn. Spawning males and females were collected beginning in mid May. The eggs were stocked in production and experimental tanks at Mote and we are currently rearing three batches of snook larvae.

ii. Develop optimal stocking strategies for snook
Fishery independent sampling to test and evaluate a snook stock enhancement prototype in nursery habitats:

Test of density-dependent displacement effects with hatchery-reared juvenile snook released in critical nursery habitats ­ experimental design:
The primary emphasis of snook experimental release-recapture studies in our proposal was to identify potential density-dependent effects in juvenile snook populations. When density dependence exists, a population size is controlled by intra-specific competition or predation for a limited resource. Therefore, interspecific competition or predation should limit further expansion of the population, thus diminishing stocking effectiveness. Density-dependence may operate principally within a specific ontogenetic stage, such as among juveniles. And multiple year classes of adult fishes may all contribute to cannibalism of juveniles. Common snook exhibit signs of density-dependency such as being piscivorus and cannibalistic. As part of a responsible approach toward our pilot studies to develop effective stock-enhancement technology for snook, the potential for density-dependence in yearling juvenile snook was investigated.

Our earlier stocking activities focused on effects of release strategies on survival and growth of hatchery-released snook. We are now focusing our attention on the interactions of hatchery-released fish with wild snook populations.

An experimental design has been implemented using releases of juvenile hatchery snook into nursery habitats around Sarasota. Before releases occurred, estimates of age - 0 and age - 1 abundances of snook in the nursery habitats were necessary. Four creeks (snook nursery habitats) were selected for this experiment: South Creek, North Creek, Bowlees Creek, and Whitaker Bayou. Pre-release sampling occurred in these creeks to determine snook abundance. Because juvenile snook abundance in these areas is generally associated with shoreline habitat, sampling effort was related to total shoreline distance. Aerial photographs (1 inch = 200 feet) were used to obtain total shoreline habitat within the creeks and every third 100' section of the shoreline was sampled. A 220 foot seine was used as the standard sampling gear, and on open shorelines (i.e. shorelines with no opposite banks within 70' of the shore) the net was deployed 70' offshore. Immediately 70' of the net was pulled to the shore while the other end was arched toward the shore approximately 100' away. In stream and canal habitats, both shores were sampled, and again, 70' of the net was used to block off the lower half of the sample section while the remaining net was pulled down one of the shorelines approximately 100' and arched across to the opposite shore. With this method, roughly every third 100' section of shoreline habitat within the creek was sampled. In many cases shoreline habitat was not sampled because of logistical difficulties, however.

This experiment began in May, 2002. Field collections to evaluate experimental treatment effects have continued, and have been the focus of directed sampling efforts during this reporting period (January through June, 2003). 2477 juvenile hatchery-reared snook had been tagged and released into creeks and estuaries around the Sarasota area. All released snook were tagged with a coded-wire tag (CWT) and a visible implant elastomer (VIE) tag. CWTs were injected into the left cheek muscle with automatic Mark IV CWT injectors (Northwest Marine Technology, Inc.). CWTs identified the experimental treatments outlined above, as well as general size classes (smalls: 70-125 mm FL; medium: 125-160 mm FL; and large: 165-270 mm FL). Fluorescent red VIE tags were injected into the caudal fins of each snook for release. This tag provided a visible identification of the released fish as hatchery reared snook.

Tagged juvenile snook were then held for 1 week to recover from the tagging process prior to the releases. Tank salinities ranged from 3 ppt - 6 ppt and water temperature between 26-30 EC.

Health certification checks were performed by an independent aquatic veterinarian, Dr. John Slaughter, on sub-sampled snook from each source group prior to tagging. Upon receiving approval for release, the tagged juvenile snook were released into four creeks in the Sarasota area, as described in the experimental design above. The juvenile snook were transported in hatchery water in tanks by truck and boat. To improve post-release survival rates, all released snook were stocked into predator-free acclimation “pens” located within the creeks and held for 3 days. These activities were based on results from experiments performed in 2000 where snook were acclimated for 3 days in situ. These results obtained from follow up sampling in the release creeks showed recapture rates 2x greater for acclimated snook than for snook released directly into the wild. This effect occurred immediately (within 30 days after the release). Samples taken 2-4 months after release, and 9 months after release again showed that recapture rates were twice as high for acclimated fish compared to non acclimated fish (p < 0.05). Therefore, on May 23, 2002, all snook were released from acclimation pens into the wild.

To determine initial tag retention rates, sub-samples of tagged fish were taken from each release group 2-3 hours before the release occurred. As a result, tag retention was checked 6 days after tagging. All fish from each release group was checked for the presence of a CWT with a CWT detector and each fish was also checked visually for the presence of a VIE. Total counts were taken from each tank to determine post-tagging mortality rates. Retention rates from the 2002 tagging activities with juvenile snook were excellent. CWT rates averaged 99.5% retention (from 14 groups with an average of 84 fish/group), and VIE retention was 100% 6 days after tagging.

Release numbers were then calculated for each creek using the available hatchery snook (~ 2800 snook). Because Whitaker Bayou and Bowlees Creek were estimated to have lower age-0 snook populations, they were chosen for “high density” releases and North Creek and South Creek were chosen for “low density” releases. Pre-release estimates of age - 0 snook in the creeks were as follows:

Creek	Wild Population Estimate	Releases Proposed % increase	*Est. Release #	Actual % inc.	Actual Release #
Bowlees Creek Whitaker Bayou North Creek South Creek	281 age-0 snook 523 age-0 snook 2509 age-0 snook 765 age-0 snook	100 100 10 10	562 1046 502 153	158.2 97.8 8.7 8.4	889 1024 436 128

The estimated release number is twice the actual number needed because previous work has shown that at least 50% mortality occurs when fish are not acclimated in pens at the release site for 3 days prior to release (Brennan et al. Unpublished data). An unknown additional post-release mortality occurs with the hatchery snook - - even with acclimation, and therefore, as a rule of thumb, 2x the actual number needed was released.

Post-release Evaluation
Post-release sampling occurred in June 2002, August, October, December, and January 2003, to determine the “permanence” of abundance changes in the 2001 year class after hatchery snook releases. Each creek (Bowlees Creek, Whitaker Bayou, North Creek, and South Creek) was sampled as described above for each sampling month. Catch per effort (CPE) was used to indicate abundance of both the 2001 and 2002 juvenile snook year classes. Respective year classes of wild snook were assigned according to length at capture based on (1) the corresponding size of hatchery released snook of the same age, and (2) sizes-at-age of snook reported in literature, and (3) young of the year snook were identified by both body length and visual examination of tissue transparency unique to young of the year snook.

A total of 3,261 snook were captured in five sampling efforts and consisted of wild snook released with tags, wild snook released without tags, 1st time wild recaptures, and hatchery recaptures. Snook recaptures, including both wild and hatchery recaptures, were present in all four creeks throughout the five sampling efforts. Hatchery fish ranged form 250-400 mm, while wild snook ranged from 75-200 mm.

In both treatment creeks (Bowlees and Whitaker), through our sampling in 2003, the 2001 year class exhibited dramatic abundance increases (40% and 120% respectively) after the releases indicating an additive effect from the hatchery fish releases. Conversely, the control creeks (North Creek and South Creek) exhibited only slight increases in abundance (4% and 9% respectively). These 1 month post-release abundance estimates indicate our earlier estimates of the 2001 year class abundance in each creek was fairly accurate (we predicted a 158%, 98%, 8% and 8% increase for Bowlees, Whitaker, North Creek, and South Creek respectively). Continued sampling through the fall season resulted in dramatic drops in abundance for the 2001 year class in all creeks. Abundance estimates of the same year class from the winter sampling, however, showed nearly identical high levels as was seen in June, 2002 and suggests that released snook may have contributed to the 2001 year class without significant mortality of either the hatchery snook or the wild snook of the same year class. We are continuing to investigate the effects of potential predation (by the released snook) on the subsequent year class, and potential within-cohort competition for resources.

The dramatic drops in abundance, seasonally, of the 2001 year class in all stocked creeks during the fall may be due to general emigration of the year class outside of the creek. If this is so, emigration from the creeks may be caused by a number of factors including (1) superior foraging habitat, (2) improved prey availability, (3) water quality preferences, and (4) ontogenetic habitat shifts. Furthermore, if foraging potential is better outside of the creek in the fall, it may be in preparation for the oncoming colder temperatures during the winter where feeding potential may be less. Future studies with acoustic tags is necessary to determine where these fish are migrating to and whether the same fish return to their nursery creek in the winter. The high winter abundance levels may also be due to mass migration to the thermal refuges in the creeks from nearby habitats and would supplement the original creek populations. We will continue to investigate these issues.

The sampling performed in the fall 2002 and winter 2003 showed age-0 recruitment of snook in the creek habitats. All age-0 snook captured were larger than approximately 60 mm FL and is an indication that our seine gear is selective for snook of this size and larger, and recruitment to the creek habitats probably occurred much earlier. The continued catch of small sized (~60 mm) age-0 snook throughout the winter and spring indicate that recruitment to the gear was continual. Furthermore, cold temperatures suppress growth and the continued catch of juveniles this size and may not indicate constant recruitment but rather catch of a slow growing year class. Literature supports these findings where small snook (around 60 - 100 mm TL) are common throughout the winter and spring, and even early summer. We will perform follow up experiments to determine the effects of releases of hatchery-reared snook on the abundance of subsequent age-0 snook populations.

Although all experimental habitat units in this study were creeks, strong differences exist between these creeks. For example, both treatment creeks, Bowlees Creek and Whitaker Bayou, represent systems that have undergone dredging operations in the past. Although Whitaker Bayou has not been dredged for over 20 years, dredging operations in Bowlees Creek are regular and performed for navigational purposes. Dredging plans in Whitaker Bayou are currently underway. Additionally both creeks are highly channelized with cement walls and drainage culverts leading into them and are located in residential areas. North Creek and South Creek (control creeks) represent relatively unaltered creeks. The upper reaches of South Creek is located within Oscar Shear State Park where no dredging, artificial channelization, or motorized boats are permitted although downstream of US Highway 41 these activities are permitted. These differences in habitat could all influence the results of this study and we plan to perform crossover experiments alternating control and treatment creeks. The selection of these creeks for this study was based on the amount of hatchery fish available for stocking. Creeks with the lowest population sizes were chosen as treatment creeks because artificially supplementing these populations to 2x their original sizes would require less juvenile snook.

We feel that these experiments need further investigation in several areas. Specifically: (1) Release magnitude needs to be increased by several fold so detection of effect size is more apparent. Releases may even need to be scaled up by an order of magnitude. (2) Intrinsic differences among release sites call for a need of crossover experiments with recruitment manipulation and creek density. To perform this, several release years are needed, and careful within-year estimations of abundance are needed. (3) We need to evaluate the effects of releases of age - 1 snook on the wild age - 0 snook, in addition to the effects within year classes.

In achieving these goals, we are continuing our standardized sampling in the nursery habitats as baseline data for future releases, when more hatchery-reared juveniles are available for release. Sampling has occured in June 2003, and will continue in October/November 2003, and January - March 2004.

Adapting Tag Technology toward Stock Enhancement of the Common Snook
Currently we are making efforts to refine VIE tag capability for stock enhancement with juvenile snook. Previous studies at Mote Marine Laboratory with VIE in juvenile snook reported promising VIE retention in the caudal fin rays, while poor retention was reported in the head and jaw areas of the juvenile snook. This manuscript (Brennan, et al.) is entitled “Adapting tag technology for stock enhancement of the common snook, Centropomus undecimalus,” and is in revision to be published in the North American Journal of Fisheries Management. The paper describes results primarily obtained from field recaptures and lab studies detailing tag experimentation work from 1997-2002 (See, 2001-2002 Final Report - MML Technical Report 761). Additionally, we are investigating the potential for use of this tag in a new site--the highly visible cornea tissue of juvenile snook. Preliminary results from laboratory studies indicate an absence of negative effects on tissue health, and high retention and visibility. We will also test this in the wild to determine potential harmful effects on fish survival and growth.

We are also developing the capability for the use of PIT (passive integrated transponder) tags in ecological studies with juvenile snook. Many studies show PIT tags to be extremely useful in ecological studies requiring multiple recaptures, individual information, and long-term data collection needs.

We have adapted PIT tags to juvenile snook for use in ecological studies testing density dependence. In these experiments, we tag wild juveniles throughout a nursery system according to size, microhabitat capture location, and date. Follow up large-scale releases will be performed in these systems and recapture efforts will determine the impact of large-scale releases on existing wild snook populations. We will look into the potential of developing and employing benign monitoring systems with these tags.

Another current development is the use of PIT tags in adult snook for spawning behavioral studies. A protracted spawning season has many biological implications such as multiple spawning efforts of individuals, energy allocation over a spawning season, changes in egg quality, and spawning site preferences. In testing the feasibility of a stock enhancement program for the common snook, development of a sound aquaculture system for snook is necessary and knowledge of snook spawning biology is an important aspect of this.

Eggs derived from different terms of the season may vary in hatching success and larval quality. An understanding of the ecological ramifications of these is important for responsibly producing progeny for year class supplementation.

Wild caught female snook are being tagged with Passive Integrated Transponder (PIT) tags throughout the spawning season of summer 2003. Each female is scanned for previous tags, measured, aged (from scale annuli, aging only first time tagged fish), given an index of maturation, and the stage at which eggs are harvested. We categorized female maturation stages as follows:

Maturation Stage Code
Unsure of sex 0
Female, but not ready 1
Female, almost ready 2
Eggs flowing 3
Spawned out 4

The stage at which eggs are harvested from mature females are assigned to codes as follows:
Eggs Harvested Code
No Eggs 0 Eggs harvested 1st try 1
Eggs harvested 2nd try 2
Eggs harvested 3rd try 3

Snook are being collected during spawning cycles on the new moon and full moon phases from May through September. Collections are conducted at spawning sites from Venice Inlet to Rattlesnake Key. Snook are captured with seines and trammel nets. All tagged fish are released after processing.

iii. Evaluate the effectiveness of snook enhancement
Fishery-independent assessment of adult habitat to identify recruitment of hatchery snook to the adult populations:

Survival of organisms in their environment is closely associated with habitat quality, as habitat provides many essential factors including suitable environmental conditions, food, and protection from predation. With large variations in habitat (structure, prey abundance, refuge) and even intrinsic mechanisms such as density dependence operating, habitat quality can have a large influence on survival and growth of a species.

To evaluate the effect of microhabitat on post-release survival and growth, in previous work, we released tagged juvenile snook into four different microhabitats (1998 and 1999). Since then we have performed standardized random sampling in the release microhabitats conducted on generally a monthly basis. As follow-up work to this work, we need to collect information from the adult fishery, which gives us information on ultimate survival and growth rates of our released fish. Fish recovered from these habitats represent long-term data and are unbiased geographically because the spawning habitats are miles from the juvenile habitats and fish recruited to these habitats originate from a collective assortment of juvenile habitat. We are in the process of producing a publication describing the results of the microhabitat study.

Throughout the summer of 2003 (May - September), sampling along beaches and passes (in adult snook spawning habitat) is being conducted to evaluate hatchery snook contribution to the adult populations. We are using a 450' seine, a 150' seine, heavy cast nets, and hook and line equipment to capture adult snook. This sampling is conducted in conjunction with aquaculture production spawns around the new and full moon phases. Each female is being marked with a pit tag, enabling multiple recaptures of each animal. This will also aid in determining if females spawn multiple times throughout the season and show site specificity (see above). A paper evaluating the movement of released juvenile fish into the adult fishery is currently in preparation.

Fishery-dependent assessment of adult habitat to identify recruitment of hatchery snook to adult populations:

6th Annual “Snook Shindig”
Activities centered around the planning, permit accrual, and general preparation for the 6th Annual Snook Shindig occurred this period. The tournament is scheduled for October 3-4th, 2003. The purpose is to continue to track the contribution of hatchery-released snook to the snook fishery in Sarasota Bay.

iv. Produce winter flounder and prepare for summer 2003 release-recapture experiments (University of New Hampshire)
The overall goal of our winter flounder stock enhancement program is to accelerate recovery of the fishery by increasing spawning stock biomass. To meet this goal, we have developed a multidimensional research program designed to produce large numbers of high quality juveniles, to optimize release strategies, and to test the feasibility of winter flounder stock enhancement. Elements of the program addressed in this reporting period have included:

Gaining additional information on the habitat requirements of juveniles.
Winter flounder are certainly among the most thoroughly studied of all marine fish species. This wealth of information will facilitate the development of a winter flounder stock enhancement program, but further information on juvenile ecology and habitat is needed before optimal release strategies can be developed. Our most recent contribution to understanding flounder ecology, funded through SCORE, has been to use Habitat Suitability Index (HSI) modeling to predict appropriate release locations for winter flounder in the Great Bay Estuary of New Hampshire. Habitat variables used in the modeling included temperature, salinity, depth, substrate type, prey availability, and predator abundance. This highly successful study was completed in late 2002, and manuscripts are being prepared for publication.

Juvenile Production
Juvenile production began in March 2003. Adult winter flounder were obtained from local commercial fishermen and transported to the UNH Coastal Marine Laboratory (CML). Several groups, each consisting of 2 males and 1 female, were held in 1m3 circular tanks supplied with flowing seawater. Spawning occurred volitionally in these systems, and embryos were moved to 6m3 tanks supplied (1 liter/min) with filtered (5 micron), ultraviolet treated, ambient temperature (5-6oC) seawater. Three to four days after hatching, microalgae were added to the tanks each day, and the larvae were fed microalgae-enriched rotifers (Brachionus sp.) twice daily at a rate of 4000 per liter. This diet was replaced by DHA SelcoTM enriched Artemia nauplii as the larvae increased in size. After the fish metamorphosed, weaning began by co-feeding enriched Artemia and the weaning diet (Biokyowa TM). Over the course of 10 days, the ratio of live food to dry diet decreased until the fish were only offered formulated food. As the fish increased in size, the weaning diet was replaced by a formulated diet produced by Nutreco (Gemma). Particle size increased as the fish grew. Approximately 30,000 juveniles (30mm) were produced.

Test the predictive capabilities of HSI models through in-situ experiments.
The Habitat Suitability Index models were used to identify 2 sites that, at least on the basis of substrate, temperature, prey availability, and predator abundance, seem to be quite suitable for winter flounder juveniles. We intend to test the predictive capabilities of this model in the summer of 2003 through in-situ experiments. In this work, we will test growth and survival at 5 geographically separate locations. Two of these will be the locations that the HSI modeling predicted as “best” in the Great Bay Estuary, and 2 will be locations the modeling predicted as “worst” in the Great Bay Estuary. The fifth location will be in the Hampton-Seabrook estuary at the proposed pilot-scale release location. Progress towards this objective have included the building of the 1m3 test enclosures and the production of the juveniles we will use in this study.

Preparation for Pilot Scale Releases
We intend to release 10,000 juvenile winter flounder in the coming year. This experimental release will allow us to: 1) estimate the mortality rate of released fish, and compare it to wild fish; 2) estimate the growth rate of released fish, and compare it to wild fish; 3) describe the diet of released fish, and compare it to wild fish; 4) study the movements of released fish, and compare them to wild fish; and 5) gain insights about the carrying capacity of the release location. During the reporting period the juveniles we will use have been produced. We also applied for and received all necessary permits, and have made arrangements for assistance in field sampling with the New Hampshire Dept. of Fish and Game and Normandeau Associates.

Tagging
All juveniles we have produced have been tagged with Coded Micro Wire Tags (CMWT) developed by Northwest Marine Technologies, Inc. Our previous tagging studies have shown that there is a size-specific mortality associated with coded wire tags. Fish � 21 (+/- 4.0) mm and 0.2 (+/-0.1) g are mortally wounded by the tagging process and /or the tags themselves, so we delayed tagging until the fish were greater than 25 mm. When the fish are released, a sample of 100 fish will be held in the laboratory to confirm tag retention. We also hope to use ultrasonic tags to monitor the small-scale (10’s of meters) movements of the released fish. Because ultrasonic tags small enough to place on fish as small as 25 mm do not currently exist, we are developing the technology in conjunction with a commercial ultrasonic tag manufacturer, Sonotronics.

Determination of Sex Ratio
Studies have shown that sexual differentiation, and therefore male:female sex ratio, in some flatfish species can be influenced by juvenile incubation temperature. This also may be true for winter flounder, whose juveniles are quite eurythermal), but sexual differentiation and the sex ratio of cultured fish have never been investigated.

Because the sex ratio of cultured winter flounder, and the factors that may influence it, are completely unknown, and because the sex ratio of stocked fish is fundamentally important, we have begun to study sexual differentiation and cultured fish sex ratio as part of this study. We have sampled 30 fish from the general culture population at approximately 10mm total length (TL) intervals, starting at metamorphosis. Sampling will continue through the first year. Tissues have been fixed in modified Davidson’s fixative, and await histological processing. Slides will be examined to view structures and cells associated with gonadal tissue. By examining the size series of fish collected, we will be able to determine the size and age when sexual differentiation occurs, as well as the sex ratio of the cultured population.

v. Develop marine fish culture policy
Florida:
In line with the short and long-term objectives of strategic planning for the Florida Fish and Wildlife Conservation Commission’s marine stock enhancement program, several steps have been made toward (1) improving the effectiveness of the Department’s marine stock enhancement program, (2) adapting and refining the aspects of a “Responsible Approach to Marine Stock Enhancement” (Blankenship and Leber, 1995) that have not yet been fully implemented in Florida, and (3) identifying and prioritizing potential marine fish species for stock enhancement in Florida. Dr. Ken Leber has been continued to work closely with the Florida Fish and Wildlife Conservation Commission’s Stock Enhancement program to further our partnership in stock enhancement. Leber has continued to work on developing and implementing pilot releases and nursery sampling of experimental juvenile red drum released made in Tampa Bay. Leber also attended several FWC staff meetings, and additional meetings with Bill Halstead, at the FWC Stock Enhancement Research Facility to assist as needed in planning and coordinating ongoing State of Florida stock enhancement efforts.

References Cited
Blankenship, H. L. and K. M. Leber. 1995. A responsible approach to marine stock enhance-ment. In Uses and effects of cultured fishes in aquatic ecosystems. American Fisheries Society Sympo-sium 15:165-175.

Leber, K. M. 2002. Advances in marine stock enhancement: shifting emphasis to theory and accountability. Pp 79-90 In Stickney, R. R. and J. P. McVey (eds) Responsible Marine Aquaculture CABI Publishing, New York.