Largemouth bass fishing has long been

Size: px

Start display at page:

Download "Largemouth bass fishing has long been"

Arabella Thornton
5 years ago
Views:

1 Fish & Wildlife Management Stocking Wild-Adult Largemouth Bass Daniel E. Canfield Jr. and Mark V. Hoyer An Additional Tool for the Management of Largemouth Bass Introduction Largemouth bass fishing has long been economically important to the State of Florida. In the late 1920s, the City of Leesburg, located on the Harris Chain of Lakes in central Florida launched the first national bass tournament and declared it was the BASS CAPITAL. Florida now has over 820,000 anglers fishing for bass alone and these anglers spent over $1 billion annually (USFWS 2006). By the late 1990s, the Harris Chain of Lakes in central Florida (Figure 1) had lost a significant amount of aquatic vegetation (habitat), and was experiencing a decline in bass populations and public perception regarding the quality of fishing (Benton 2000). Bass reproduction was greatly reduced. Rooted aquatic vegetation coverage at Lake Griffin had declined from close to 50 percent in the late 1940s to virtually 0 percent by Total bass angling effort at Lake Griffin also declined from over 60,000 hours when first measured in the late 1960s to less than 800 hours by Associated with the loss of vegetation was the loss of a multimillion-dollar largemouth bass fishery, which significantly hurt the economic activity and image of Florida s BASS Capital, the City of Leesburg. Stocking of largemouth bass is an important management tool for fish management, but the stocking of hatchery-produced fingerling or advanced-fingerling bass to supplement bass year-classes has been met with varied success. Applying a different approach, this paper examines a multiyear stocking program moving wild-adult largemouth bass from non-fished nearby water into Figure 1. Map showing the locations of the Harris Chain of Lakes, FL (source: 2013 Google Maps). 3,800 ha Lake Griffin and 1,811 ha Lake Dora. Both lakes are in the Harris Chain of Lakes. The Harris Chain of Lakes Restoration Council, established in 2001 by the Florida Legislature (Chapter F. S.), responded to the demise of the bass fishery in 2004 by recommending funding for a wild-adult largemouth bass stocking program. The recommendation came after due consideration of many management options ranging from eutrophication control, water level fluctuation/drawdown, and the stocking of hatchery-produced fingerling or advanced fingerling largemouth bass. Here, we provide information for implementing a wild-adult largemouth bass stocking program as this could be a tool lake managers could utilize to provide communities economic relief while longterm restoration programs are underway. Study lakes The primary study lake was Lake Griffin, a 3,800-ha lake (6,680 ha with Spring 2013 / LAKELINE 27

2 associated marshes; see Pecora 2009) located at the downstream end of the Harris Chain of Lakes. The lake is the headwater of the Oklawaha River, which has a lock and dam (Moss Bluff) to control water discharge from the lake to the river. The second study lake was Lake Dora (1,811 ha). Dora was chosen because the largemouth bass fishery, next to Lake Apopka and Lake Griffin, was one of the poorest in the Harris Chain of Lakes. Because of its smaller size and lack of multiple access canals, fish egress would be more limited and permit a better assessment of the impact of wild-adult stocking on the lake s native largemouth bass population. Like Lake Griffin, Lake Dora by the 2000s had limited aquatic vegetation. Donor sites To begin a large-scale, wild-adult largemouth bass fish transfer project, a suitable (non-public fishing water) donor site, capable of producing 4,000-plus bass per year, was needed. A partnership was established with the Greater Orlando Aviation Authority, which offered the waters located at the Orlando International Airport (MCO). MCO proved to be an excellent donor site for the collection of adult largemouth bass because of the large number of accessible water bodies (over 85 small lakes and ponds, most < 10 ha in size and interconnected by drainage canals). All largemouth bass were collected under the auspices of a scientific collection permit from Florida Fish and Wildlife Conservation Commission (FWCC), which stipulated that only Micropterus salmoides floridanus be transferred into Lake Griffin and Lake Dora. The genetic makeup of largemouth bass populations at MCO was assessed using electrophoresis methods (Childress 2004). All stocked bass were examined visually to determine if the fish were healthy (any questionable fish was not transported). Stocked fish were measured to the nearest millimeter for total length (TL) and given a left-pelvic fin clip prior to being transferred. Bass larger than 275 mm TL were implanted with either an orange or yellow Hallprint type PDA plastic-tipped dart tag (Figure 2). The tag was imprinted with an individual identification number and a contact telephone number for Florida LAKEWATCH to aid in angler reporting. No reward ($) was associated with the tag. Lake Griffin was stocked for three years and Lake Dora was stocked for two years (Figure 3). Evaluation of effectiveness Immediately after each December May period of stocking, an evaluation of the transfer program s potential increase to the resident largemouth bass population was conducted by collecting largemouth bass via electrofishing from near-shore waters of Lake Griffin and Lake Dora (Figure 4). Largemouth bass were sampled at multiple transects (>15), which were spaced equal distances around the perimeter of each lake. Ten minutes of electrofishing were conducted at each transect to capture largemouth bass greater than 200 mm TL. Sampled fish were examined for pelvic fin-clips and/ or Hallprint dart tags. The number of marked and unmarked largemouth bass was recorded to determine the percentage of stocked fish in each lake s largemouth bass population. A roving creel survey is conducted by FWCC annually at different lakes as part of the Harris Chain of Lakes monitoring program. To further our understanding of the impact of stocked fish, a creel survey June 2006 through March 2007 was conducted at Lake Griffin in partnership with FWCC. The creel survey was conducted on the main part of Lake Griffin and was not conducted on the many canals and other backwater/ marsh areas connected to the lake. Data were analyzed by FWCC using their creel analysis program (Creel Analysis Version 1.0, located at the FWCC Eustis laboratory). Collection and transfer To collect wild-adult largemouth bass for transportation, healthy fish were captured by use of electrofishing (a technique used worldwide). Bass were transferred only between December 1 and May 1, when water temperatures were below the 26 C. This thermal limit was mandated by the FWCC to minimize death due to handling stress. Figure 2. Measuring and tagging largemouth bass for stocking into Lake Griffin. 28 Spring 2013 / LAKELINE

Figure 3. Stocked wild adult Largemouth Bass into Lake Griffin. Figure 4. Electrofishing survey to determine impact of stocking largemouth bass into Lake Dora.

24,781 fish with 13,932 (approximately 4 fish/ha) transferred into Lake Griffin and 10,849 (approximately 6 fish/ha) transferred into Lake Dora (Table 1).

3 Figure 3. Stocked wild adult Largemouth Bass into Lake Griffin. Figure 4. Electrofishing survey to determine impact of stocking largemouth bass into Lake Dora. Results Wild Bass Stocking Feasibility The total number of largemouth bass over 200 mm TL stocked into the Harris Chain of Lakes (Lake Griffin and Lake Dora) between December 2004 and April 2010 was 24,781 fish with 13,932 (approximately 4 fish/ha) transferred into Lake Griffin and 10,849 (approximately 6 fish/ha) transferred into Lake Dora (Table 1). For all years with the exception of 2009 (funding limitations; 1,196 fish for Lake Dora), 4000 plus bass per year were stocked. LAKEWATCH personnel and volunteer-anglers surveyed the lakes (up to two weeks) after each stocking event and found no large mortality events. Electrofishing surveys in May/ June revealed between 10percent and 13 percent stocked bass at Lake Griffin and about 22 percent at Lake Dora (Table 1), suggesting that the stocking of wild caught largemouth bass did increase the populations significantly. Lake Griffin Creel Survey FWCC s creel survey results at Lake Griffin showed that the 2002/2003 largemouth bass fishing effort at Lake Griffin was 724 ± 168 angler-hours, but increased in 2003/2004 to 2,649 ± 533 angler-hours. After the first year of stocking wild adult largemouth bass, angler effort in 2005/2006 was estimated at 4,034 ± 675 angler-hours. In , the fishing effort had increased to 6,443 ± 1,012 angler-hours. FWCC, however, reported low numbers of tagged bass caught by anglers. The low number of tags found in the creel study could be explained by egress of fish into adjacent canals and marshes, however, more detailed studies (including radio tagged fish) need to be conducted to evaluate actual mortality and movement rates of stocked fish, but there is no doubt fish move which becomes a major issue in open-systems. Angler Call-in Data Between January 1, 2006 and December 31, 2007, anglers placed 377 phone calls (293 calls in 2006 and 84 calls in 2007) reporting catches of tagged fish at Lake Griffin. These calls came to LAKEWATCH without any advertisement of the stocking program, public announcements requesting anglers to report caught tagged-fish, or monetary rewards for reporting tagged fish. Catch locations (326) and the kept or release status (319) of fish were recorded. Largemouth bass were caught at 84 (26 percent) locations within the main part of Lake Griffin where FWCC conducted their creel survey. Most fish (65 percent) were caught from adjacent waters (e.g., connected canals and marshes), but 30 bass (9 percent) were from other waters (e.g., Lake Harris). For bass where the kept or release status was reported, 287 (90 percent) fish were released and 32 (10 percent) fish were kept. Spring 2013 / LAKELINE 29

4 Table 1. Yearly summary of the number and size (mm TL) of wild largemouth bass stocked into Lake Griffin and Lake Dora of the Harris Chain of Lakes, Florida. Numbers in parentheses are the percent contribution estimates based on electrofishing catches one month after the end of each year s stocking effort. Year Total >275 mmtl >356 mmtl >432 mmtl >508 mmtl Lake Griffin ,234 (10) 1,762 1, ,032 (10) 3,586 1, ,666 (13) 2,122 1, Lake Dora ,622 (22) 2,092 1, ,196 (NA) ,031 (21) 4,220 2, Between December 2008 and July 2010, anglers placed 87 phone calls to report catches of tagged fish on Lake Dora. Anglers made 167 call-ins for the entire Harris Chain of Lakes. Persistence of stocked bass in Lake Griffin The last wild adult-bass stocking at Lake Griffin occurred in March In May and June 2007, the highest percent (13 percent main lake) of stocked fish was captured by use of electrofishing. Two years later, stocked largemouth bass were still present, but at a reduced level (2 percent in main lake). A similar trend was documented in Lake Griffin s canals (15 percent in 2007; 4 percent in 2009). FWCC reported 0 percent for their electrofishing surveys. Anglers, however, still phoned in reports of catches. In 2011, anglers from the Bass Anglers Sportsman Society (B.A.S.S) 2011 Elite Series Sunshine Showdown on the Harris Chain of Lakes caught tagged bass from Lake Griffin that helped place them in the money (HCOLRC 2011; see report cover). Costs/benefits Total expenditures for the stocking and evaluation programs at Lake Griffin and Lake Dora since 2004 were $492,775. This figure included University overhead (5 percent) and infrastructure (e.g., boat, hauling box, and truck) costs. For the 24,781 bass transferred the cost was, therefore, $19.89 per fish. For just the capture and transport of the fish alone (not including evaluations, infrastructure, or overhead), the total expenditure was approximately $250,000 or $10.09 per fish. When assigning an aquatic animal damage value to fish losses due to pollution, the State of Florida established a replacement (assuming no recreational value for non-fished waters) and a recreational value (public fishing waters) in 1993 for different size largemouth bass (Florida Administrative Code ). Using these values (corrected for inflation to 2010 dollars) to assess the monetary value of the transferred fish, the total replacement value for the Harris Chain of Lakes since 2004 was $441,634 and the recreational value was $462,086. If only the cost of capture and transport are considered, the cost/benefit ratios would be $1.77/$1.00 spent for replacement and $1.85/$1.00 spent recreational costs. Discussion When it was first proposed to stock wild-adult bass into the 3,800-ha Lake Griffin, it was questioned whether a sufficient number of bass could be obtained to increase the number of bass in the lake significantly. The Lake Griffin/Lake Dora study clearly demonstrated that the number of adultbass in a large (>1,000 ha) water body could be substantially increased (> 10 percent) through the stocking of wildadult largemouth bass (Table 1) and that the angling community immediately utilized these fish (as shown by the large number of angler call-ins). The impact of using this stocking approach clearly would be even greater if smaller (< 500 ha), heavily-fished water bodies, often identified by agencies for stocking, were chosen for stocking large numbers of wild-adult bass. The success or failure of any stocking will ultimately be judged on economics. For the Lake Griffin/Lake Dora stocking program, the 24,781 bass were transferred at a cost of between $10.09 and $19.89 per fish depending on how the costs of the project are calculated ($250,000 for just the capture and transport of the fish or $492,775 for the total project). Opponents of the Harris Chain of Lakes stocking pointed to the high cost per fish as the reason such a program should not be supported. However, the three-day 2011 Elite Series Sunshine Showdown tournament at the Harris Chain of Lakes generated a direct economic impact for the City of Tavares and Lake County of $553,000, and an indirect and induced impact of more than $1.65 million (Tavares Economic Development Department, Director Bill Neron). As an alternative, the stocking of hatchery-reared fish recommended because the cost per fish is lower for fingerling or advanced-fingerling largemouth bass (typically $1 or less). These figures rise substantially, however, when mortality losses are considered over the time period it takes for a fingerling or advanced-fingerling to reach the legal size limit. For example, if one million fish were stocked at a cost of $1 and only 10 percent survive to legal size the cost become $100 per fish. What is clear from this study based on the weight of evidence, a wild-adult bass stocking program generates a positive return on the investment in a short period of time! In the perfect world, managers strive to maintain a quality environment, including habitat, in order to perpetuate a quality fisheries. Unfortunately, many 30 Spring 2013 / LAKELINE

environments become degraded causing a loss of fisheries such as happened at the Harris Chain of Lakes, once considered the BASS CAPITAL of the world.

dollars and may not have a noticeable effect for decades. Sometimes, a recommended fish management program, such as lake drawdown, cannot be accomplished because of political opposition.

The results of this study demonstrate that transferring wild-adult largemouth bass from non-fished waters represents a viable fish management strategy for large Florida waters and undoubtedly for

5 environments become degraded causing a loss of fisheries such as happened at the Harris Chain of Lakes, once considered the BASS CAPITAL of the world. The first step in correcting the problem in the eyes of the scientific community is the restoration of optimal environmental conditions, but most environmental restoration programs cost millions of dollars and may not have a noticeable effect for decades. Sometimes, a recommended fish management program, such as lake drawdown, cannot be accomplished because of political opposition. When such situations arise, the stocking of hatchery raised and now maybe wild adult fish is an additional fisheries management tool that can help mitigate economic losses to surrounding communities. The results of this study demonstrate that transferring wild-adult largemouth bass from non-fished waters represents a viable fish management strategy for large Florida waters and undoubtedly for waters elsewhere. Federal, state, and local fish management agencies have electrofishing boats and fish-hauling equipment so the cost of adult-bass transfer-programs should be less than the costs generated during the Harris Chain of Lakes wildadult bass transfer demonstration projects. The stocking of hatchery raised and wild adult-bass can bring economic benefits to the surrounding communities that exceed the costs of the stocking program. However, an issue that must be addressed is the true costs of stocking hatchery-produced fingerling, advanced fingerling, and wild adult bass. Specifically, all survival rates need to be understood as well as how long it will take for the hatcheryproduced fish to reach catchable legal size. If survival rates of hatchery-produced fish are low, the cost per hatchery-produced fish will probably exceed the cost per fish generated by a wild adult stocking program. Certainly, hatcheries have been and still are important in fish management, but the stocking of wild adult fish should be considered as an additional largemouth bass management tool. References Benton, J.W Central Florida fisheries development: Lake Griffin fisheries improvement Annual report for Florida Game and Freshwater Fish Commission. Tallahassee, Florida. pp Childress, J.R Identification of Micropterus salmoides floridanus populations in barrow pit ponds using cellulose acetate electrophoresis. M.S. Thesis. University of Florida. Gainesville, Florida. Pecora, D. J., Effects Of Stocking Wild-Adult Largemouth Bass On The Fishery At Lake Griffin, Florida. Master of Science Thesis. Library, University of Florida. Gainesville, Florida. U.S. Department of Interior, Fish and Wildlife Service and U.S. Department of Commerce, Census Bureau National survey of fishing, hunting, and wildlife-associated recreation. Dan Canfield is a professor of limnology in the University of Florida s Department of Fisheries and Aquatic Sciences. He joined the UF faculty in 1979 and began his research program by studying the regional limnology of Florida lakes. He is the founder and director of Florida LAKEWATCH. Dr. Canfield has served as president of the North American Lake Management Society (NALMS), and he is a recipient of its prestigious Secchi Disk Award. Mark Hoyer is the Assistant Director of Research and Program Services (Florida LAKEWATCH) in the Department of Fisheries and Aquatic Sciences, University of Florida. Mark has worked on the relationships among water chemistry, aquatic macrophyte communities, fish and aquatic bird communities in Florida streams, lakes and estuaries for the last 30 years. Mark has also been a NALMS member for over 25 years and served as President in c Spring 2013 / LAKELINE 31

Behavior and survival of hatchery reared advanced fingerling largemouth bass using radio telemetry. Brandon Thompson

Behavior and survival of hatchery reared advanced fingerling largemouth bass using radio telemetry Brandon Thompson Florida largemouth bass Micropterus salmoides floridanus Premier freshwater sportfish