II. HABITAT MANAGEMENT STRATEGIES.
Florida has close to 7,700 lakes that cover 3 million acres. Each lake has its own hydrological, thermal, visual, chemical, and biological characteristics (Seaman Jr. 1985). These characteristics create a habitat that in turn supports fish populations. Differing habitats strongly affect the resulting fish populations. Trophic status, plant coverage, and water quality directly affect fish population health. Knowing the acceptable and preferred habitats for sportfish populations is very valuable in creating sustainable sport fisheries.
Habitat management is the most important component of maintaining good fisheries. Proper habitat is critical for improvement and/or maintenance of black bass populations. There are three main areas of focus where FWC has a positive impact on habitat. First, FWC creates short- and long-term plans and projects to enhance and maintain black bass populations. Second, the FWC plans for the long-term health of our black bass populations by dedicating staff and utilizing resources to engage stakeholder groups, other agencies, and non-governmental groups to help shape management decisions. Lastly, biologists develop individual monitoring programs associated with proposed action items to: 1) Make sure the intended action is having the desired result on the black bass population, and 2) Identify actions items that need additional research and planning before it can become a viable management option. Providing appropriate research and monitoring within the context of this program will ensure that actions taken are science based and supported by an active research program.
- Prevent habitat degradation in areas of existing healthy habitat in collaboration with other agencies as needed.
Staff engages state and local regulatory agencies and affected parties on permittable actions that may negatively affect significant areas of bass habitat. Additionally, FWC staff should be engaged in the state Comprehensive Planning process as Developments of Regional Impact (DRIs) are being discussed. An example of this was the recent formation of the Lake Toho DRI interagency team (FWC, Osceola County, East Central Florida Planning Council, various planners and developers, SFWMD, DEP, USFWS, USACE, EPA, etc.) that met and worked with the planners of five DRIs and the East Central Florida Planning Council to develop a plan for the shoreline of Lake Toho (around 20 miles of shoreline). Amenities may be added like a fishing pier to serve all residents instead of individual lot owners building private ones. Planners and developers benefitted by streamlining permit processes. The lake environment benefitted by protecting littoral zone habitats and the floodplain, thus protecting fish and wildlife needs.
Monitor water bodies that have had robust healthy vegetation and newly revegetated water bodies to compare fisheries. By partnering with other agencies, an action plan will be created to reduce anthropogenic effects on quality habitat to address problems before damage becomes irreversible.
- Manage native plants to create and maintain a symbiotic relationship between plants, fish, and people that will improve and sustain black bass fisheries.
Aquatic macrophytes are important to the function of a lake ecosystem and provide valuable fish and wildlife habitat, improves water quality and clarity, and reduces shoreline erosion resulting in resuspension of sediments (Smart et al. 1998). For largemouth bass aquatic vegetation provides structural habitat for refuge and food resources (Moxley and Langford 1982). Additionally, largemouth bass anglers often prefer to fish in or around aquatic vegetation (Wilde et al. 1992). However, if aquatic vegetation becomes too dense, largemouth bass growth and condition has been shown to decline (Colle and Shireman 1980; Maceina and Shireman 1982) possible the result of reduced foraging efficiency (Bettoli et al. 1992). Macrophyte removal can improve fish growth and size structure in lakes where high densities of plants have resulted in stunted fish populations (Olsen et al. 1998).
One of the major factors contributing to the proliferation of aquatic vegetation in the littoral zone of many Florida lakes is water level stabilization. Natural flows and levels have been altered primarily for flood control and have had adverse affects on native plant communities (Moyer et al. 1995; Allen and Tugend 2002). Water stabilization on Lake Kissimmee has lead to dense stands (percent coverage of 100%) of pickerel weed Pontederia cordata, cattail Typha spp., smartweed Polygonum spp., and water primrose Ludwigia spp. in the littoral zone (Moyer et al 1995). These species create monocultures and where plant biomass was more than 50 kg/m2, dissolved oxygen levels were less than 2 mg/L, centrarchid species were absent and species richness was low (Allen and Tugend 2002). Additionally, natural shedding and leaf litter from these species can increase the amount of organic sedimentation and decrease plant diversity through competition. For example, cattail produces a dense rhizome mat and the clustered leaves cause litter. Dense cattail growth and litter may reduce the opportunity for other plants to establish or survive (Apfelbaum 1985). Mineralized substrates necessary for many plants to germinate are buried by this litter. Beneath the litter, substrates are cool and moist, optimal conditions for survival of a seed bank but not for seed germination (van der Valk and Davis 1978). Periodic herbicide applications are necessary to reduce biomass of many of these invasive species, promote species diversity and expansion, open areas to allow for wind and wave action to reduce organic buildup, provide better fish and wildlife habitat, and open access to anglers.
The scientific literature suggests that intermediate levels of aquatic macrophyte coverage provides quality habitat for largemouth bass; however, defining what level constitutes intermediate coverage varies between lakes and lake managers. For example, Bonvechio and Bonvechio (2006) recommended an intermediate level of aquatic vegetation on Lake Tohopekaliga of 20-40 percent to meet the needs of anglers and non-anglers. Conversely, Hoyer and Canfield (1996) found no significant relationship between macrophyte abundance and estimates of adult largemouth bass abundance and standing crop (kg/ha). However, Maceina (1996) reanalyzed the data of Hoyer and Canfield (1996) based on lake size and found in lakes greater than 54ha sub-adult and adult largemouth bass densities (N/ha) had a parabolic relationship with percent area coverage of vegetation with an asymptote at around 40-60 percent. These results as well as others suggest a lake specific approach to determine the level of aquatic plant management is needed to maintain or enhance largemouth bass populations. There are current operations in place to control nuisance native vegetation in particular water bodies to obtain a desired future condition. Plant control varies highly from lake to lake and between individual managers. Lake specific management plans should be developed for specific waterbodies when managing for largemouth bass.
- Implement FWC's new hydrilla-management position on specific waterbodies to improve largemouth bass fishing.
Hydrilla management occurs annually on many public water bodies. In the past its status as an invasive exotic plant meant it was controlled at the lowest feasible level, but hydrilla may be able to be utilized to have a positive impact on bass fisheries in some systems where native plants are not able to sustain healthy growth. In Florida lakes, hydrilla at low to moderate coverage can provide a benefit to fish populations when native submersed vegetation is limited or absent. Like all submersed vegetation, hydrilla provides substrate for high densities of macroinvertebrates as a food source for fish and cover from predation (Moxley and Langford 1982). Juvenile sport fish (e.g., largemouth bass, bluegill) production and survival has been positively correlated to increased coverage of aquatic macrophytes (Hoyer and Canfield 1996; Maceina 1996) including hydrilla (Moxley and Langford 1982; Tate et al. 2003; Sammons et al. 2005). Similarly, sub-adult and harvestable largemouth bass abundance on large Florida lakes (more than 55 ha) increased with increasing vegetation and reached an asymptote at 40-60 percent coverage but declined when coverage exceeded 60 percent (Hoyer and Canfield 1996; Maceina 1996). Studies have indicated that hydrilla infestations (e.g., >60% coverage) can adversely affect growth and condition of sport fish species (Colle and Shireman 1980; Maceina and Shireman 1982; Sammons et al. 2005). Thus, intermediate levels of aquatic plant coverage (20-40%) have been suggested to meet the needs of anglers and non-angling groups (Bonvechio and Bonvechio 2006). Anglers often prefer to fish in or near aquatic plants (Wilde et al. 1992; Slipke et al. 1998). Hydrilla has the ability to grow with limited sunlight (1%) in depths up to 15 m (Langland 1996) allowing it to provide offshore habitat in areas where native vegetation may be limited or absent. In Florida, many anglers prefer to fish within or around the edges of offshore stands of hydrilla. Angler catch rates for largemouth bass and harvest of black crappie have been positively correlated to hydrilla coverage (Maceina and Reeves 1996; Bonvechio and Bonvechio 2006). However, when coverage limits access, angler effort and catch have been shown to decline resulting in economic loss to the community (Colle et al. 1987; Slipke et al. 1998). Conversely, hydrilla at intermediate levels on Lake Okeechobee accounted for $4 million in recreational value (Furse and Fox 1994). Fisheries managers must also consider the angler use of the resource. Species-directed effort may shift with increasing hydrilla coverage because largemouth bass anglers prefer higher levels of aquatic vegetation and others (e.g., catfish, sunfish anglers) prefer less vegetation (Slipke et al. 1998). Careful consideration by fisheries managers must be given when determining the level of hydrilla management to meet the needs of the anglers that use the resource.
While many largemouth bass anglers desire hydrilla in the waterbodies they fish, resource managers must also consider the broad diversity of stakeholders who utilize Florida's public waterbodies, and each has their own preference for how aquatic plants should be managed. For example, fisherman and duck hunters may desire hydrilla at some level where lake front homeowners, swimmers, and water skiers may not want any hydrilla. Additionally resource managers may have concerns with allowing hydrilla to grow due to its fast growth rates, reproductive capabilities, ability to grow in depths up to 15m, having the potential to completely cover a waterbody within a growing season, and limited cost effective methods for control (i.e., herbicides). At high levels hydrilla can interfere with the use and function of a waterbody by adversely affect native plant communities, reducing recreational use, and creating potential health risks such as interfering with flood control. Because of the challenges managing this exotic species the FWC Invasive Plant Management Section with input from the various FWC guilds have developed an agency positions statement which will guide the agency in managing hydrilla in the future:
It is the position of the Florida Fish and Wildlife Conservation Commission (FWC) that native aquatic plant communities provide ecological functions that support diverse native fish and wildlife communities in Florida water bodies. FWC considers hydrilla to be an invasive, non-native aquatic plant that can, at high densities, adversely impact native plant abundance, sportfish growth, recreational use, flood control, and dissolved oxygen. Once established, hydrilla has proven difficult if not impossible to eradicate with current technology and is expensive to manage. Therefore, FWC opposes the deliberate introduction of hydrilla into waterbodies where it is not currently present. The FWC prefers to manage for native aquatic plants, but recognizes that in water bodies where native submersed aquatic plants are absent or limited, hydrilla at low to moderate densities can be beneficial to fish and wildlife. FWC will manage hydrilla on a water body by water body basis using a risk-based approach to determine the level of management.
In water bodies where hydrilla is well established, it will be managed at levels that are commensurate with the primary uses and functions of the water body and fish and wildlife. FWC will determine the level of hydrilla management on each public waterbody using a risk-based analysis that considers human safety issues, economic concerns, budgetary constraints, fish and wildlife values, and recreational use, with input from resource management partners and local stakeholders. Factors such as available control technology (e.g. herbicides), current waterbody condition, and activities occurring within the watershed will also influence the timing and level of hydrilla management.
Thus, future hydrilla management will be considered on a waterbody by waterbody basis using a risk-based approach with input from FWC and other state and local government resource managers and local stakeholders. (Visit the following link for a more detailed discussion about this controversial topic: Pros/Cons)
- Partner with water management districts and the Corps of Engineers to develop new water regulation schedules and to monitor and recommend minimum flows and levels to help maintain healthy black bass populations.
Stabilization of water levels have caused problems with muck build-up and water quality as well as disrupted the dynamic ecology that Florida's aquatic dependent species have evolved around. Increasing the fluctuations in water level where they have previously been stabilized is occurring throughout the state. Probably one of the most well known examples is the restoration of portions of the Kissimmee River. The restoration of the Kissimmee River by the U.S. Army Corps of Engineers along with the South Florida Water Management District is considered one of the largest restoration projects of its kind in the world, and will allow the floodplain to flood and dry according to the amount of rainfall. Low water allows organic material to dry up and consolidate, allowing emergent vegetation to begin growing. High water strands floating vegetation and decreases density and areal coverage of submersed and emergent aquatic vegetation. Low water begins the cycle again.
Water regulation schedules are used on many lakes in Central and South Florida to reduce the impact of flooding caused by excessive tropical rains mainly in summer months. The FWC does not have direct authority with respect to schedule management but can influence the agencies responsible for implementing these schedules to consider adequate levels are maintained for black bass populations. Fisheries impacts are in many cases already documented, and FWC staff can use this data to persuade other interests about the value of natural flow regimes. Freshwater fisheries staff should engage WMDs and stakeholders when water schedules are being adapted. Biologist will continue to document flow and their impact on bass in areas that are not currently covered by a water schedule.
There is a growing understanding that there will be an increased need for municipal, agricultural and commercial water supplies. Florida's five water management districts and the Department of Environmental Protection need to balance these needs with the ecological needs of fish and wildlife. FWC has a team that is prioritizing important water bodies on which they will work with WMDs to establish minimum flows and levels. Important bass fisheries will be one of their priorities.
Bass are able to thrive at many different water levels. However, seasonal impact of flows and levels needs to be better understood. WMDs use different methods to set flows and levels making it difficult to compare strategies. There is an action plan and studies are on tap to use several approaches at one location to see how close each district's methods are for relatable data comparison .
- Improve bass habitat conditions by manipulating water levels for fisheries enhancement purposes.
Drawdowns, with and without organic removal, have been used in Florida to enhance fish and wildlife habitat and mitigate for water level stabilization. Examples of drawdowns with organic material removal include the Kissimmee and Alligator Chain of Lakes, Lake Istokpoga and Lake Josephine. A drawdown on Lake Tohopekaliga was shown to have an immediate positive fish response (Moyer et al. 1995). Collaborate with WMDs and COE to implement short-term drawdowns of priority water bodies to benefit black bass populations. Create a list of priority water bodies that are eligible for drawdown (e.g., have a water control structure) based on existing habitat coverage, recruitment strength, size structure, and angler success. Lakes with stabilized water levels experience accelerated lake succession and require drawdowns and mechanical removal of organics to maintain quality habitat. Lakes with unregulated water levels experience natural high- and low-water levels and less restoration efforts over time. Unfortunately due to political, permitting, and other socio-economical reasons these management tools are not always available. Muck removal is important to the success of reemerging plant life. River channels across the country have been channelized (straightened) to provide for flood control or better navigation. Channelization provides for swifter currents and eliminates habitat. Increased water flow and decreased habitats have lead to diminished bass populations. In some areas, the need for flood control has been eliminated through other means and in other cases navigation is no longer needed. Woody debris can be added to provide habitat that has been lost as restoration proceeds to restore slow current river channels.
It has been demonstrated in Florida (e.g., Lake Griffin, Rodman Reservoir) that water level manipulation for fisheries enhancement can improve habitat, supplement terrestrial habitat growth, and substantially improve bass recruitment and adult bass abundance. Evaluate lakes/reservoirs that are able to undergo hydrologic manipulations. The information can then be used by managers to justify future water level manipulations to cooperators and stakeholders. Effects both positive and negative to other wildlife, including birds, reptiles, and amphibians, will be considered. These projects are dynamic and usually long standing, therefore research will take time to produce valuable insight, but it will be invaluable to managers and the wildlife communities.
- Revegetate lakes where a high probability of successful expansion of native aquatic plants exists.
Revegetation projects have been quite successful in many lake systems at reestablishing native plants along lake shores. Bass are drawn to properly vegetated areas to forage and to reproduce, therefore anglers target these areas. Bass spend varying amounts of time between inshore and offshore habitats, and it has been shown that inshore bass prefer habitats with vegetation (Colle et al. 1989). Not all lakes support quality vegetation, so small test plots are recommended first. Then, if the plants are successful, a major effort will be requested. The need for habitat improvement and/ or expansion on various lakes will be identified regionally and applications coordinated through the ARES to address funding of these projects.
Identifify characteristics of additional fisheries habitat that help create or maintain healthy bass populations and maintain or increase these forage and spawning grounds. Monitor revegetation projects to determine their success or failure related to individual lake parameters, like soil type and trophic level, to help in planning for future revegetation projects.
- Restore wetlands adjacent to potential fisheries to promote healthy lake waters and protect wetland wildlife communities.
Wetlands act as a natural biological filter that uses plants and algae to removal harmful excess nutrients that can cause adverse water conditions that in time can lead to massive fish kills. To accomplish this we will partner with municipal groups that provide critical education on upland management and their impact on lakes and water quality (e.g., Lakes Education/Action Drive in Polk County; www.le-ad.org). An example of a restored wetland is adjacent to Lake Griffin. Wetland restoration and enhancement has also been conducted on the Kissimmee Chain of Lakes in cooperation with SFWMD; many more opportunities still exist around the Kissimmee Chain on SFWMD lands.
- Create structural habitat in water bodies to increase/improve fishing opportunities in new water bodies.
Limited application but applicable in future planning. Water treatment and storage areas will only increase in number in the future, along with some ponds being created specifically for education/outreach purposes, or even new golf course ponds. Becoming involved with other agencies during the design phase may lead to more desirable fish habitat in these water bodies, better shoreline access, and refuges for fish that anglers can target. Sculpturing recommendations for ponds have been made by the University of Florida and by the FWC (FWC 2009). Creating structural habitat on shoreline areas will allow more anglers to enjoy the resource by creating quality fisheries that are accessible by shoreline anglers. Examples of such shoreline modifications include creation of large gravel beds on Lake Eustis and enhanced access on several Tenoroc Lakes.
Document changes in angler use and success on water-bodies where structural habitat has been created. This information will provide biologists with justification for future enhancement activities on additional water-bodies.
- Create a substrate enhancement program that incorporates a FWC/volunteer run project to construct fish attractors to concentrate fish, and improve catch rates and angler satisfaction.
Adding substrates (e.g., trees, rock, block) has been shown to improve fisheries habitat diversity and congregate fish to improve angling success or satisfaction, but requires additional research and alternate approaches to justify costs. Crushed rock or oyster shells have been used to serve as fish attractors for bream. Other artificial substrates have been introduced into water bodies for a variety of reasons. (Tugend et al. 2002; Wilbur 1978). Rip Rap or concrete and rock structures have been shown to hold bass. Fallen trees can provide favorable bass habitat in both flowing and static waters. Floating feeders have also been used to concentrate forage species, which in turn attracts bass. Native plants like bulrush and eel grass also make excellent fish attractors where applicable, and natural or artificial grassbeds have been attractors shown to increase abundance of juvenile largemouth bass (Ratcliff et al. 2009). Another potential positive is that adding artificial structure may also increase nest building and reproduction in bass (Hunt and Annett 2002). These structures provide opportunities in lakes with little or no submersed vegetation. An artificial fish attractor program will require minimal funding and manpower. These are more visible to the public than other FWC activities and in the past served as excellent public relations tools. Habitat can also be increased by placing attractors offshore, where it is too deep for submersed vegetation to grow.
Research should be done on the efficacy of installing rock pile fish attractors in lakes, because rock piles last for decades as opposed to brush, which only lasts a few years. Rock-pile fish attractors are currently being installed in the Harris Chain of Lakes in a cooperative project with Florida LakeWatch. There are research opportunities at Tenoroc FMA where crushed rock has been used extensively. Data generated from this program will show tendencies of different fish species and angler use of various attractor materials. Since fish attractors are generally expected to congregate fish, not to significantly increase fish production, we should document angler use, success, and attitudes about attractors.
- Adhere to and promote appropriate water quality standards to support black bass species.
The Department of Environmental Protection monitors water quality standards (set by the Environmental Protection Agency) to ensure water bodies are maintained within designated levels tested safe for human populations. These standards have also been used to help set standards for healthy fish populations. Largemouth bass can tolerate a wide range in some parameters and narrow ranges in others. Many of these parameters have direct effects on each other and can fluctuate greatly in a 24-hour period, but over the course of a year closely fall within seasonal historical data. The main parameters are temperature, oxygen, pH, total ammonia nitrogen, alkalinity, and hardness (Cech J.R. 1979, Seaman Jr. 1985, Stuber R.J. et al. 1982, U.S. EPA Office of Water 2009).
Record baseline water quality data in lakes where Phase-I or II black bass are to be stocked prior to release. Data may lead to an answer for why the population has diminished and a solution to the problem could be implemented allowing for acceptable water quality to be restored.
- Identify, protect and repair damaged habitat that is critical to sustain shoal and Suwannee bass populations.
Shoal and Suwannee bass are both habitat specialists that frequently inhabit moderate to swift current in rocky areas (Bass and Hitt 1973; Schramm and Maceina 1986; Wheeler and Allen 2003; Boschung and Mayden 2004). Specific critical habitats need to be identified for these species; particularly spawning habitat for shoal bass.
Protection, maintenance, and restoration of critical habitat are important for these species of black bass that occupy a small range. Critical habitats and threats to these habitats should be identified and mapped for their respective river systems. The importance of these habitats should be communicated to stakeholders and championed by managers. Shoal and Suwannee bass are rare and only found in Florida, Georgia and Alabama. Proper habitat is vital for their continued existence and for future fisheries.
Threats to shoal bass habitat, degraded habitats, and habitat protection and restoration solutions have been identified for the Chipola River watershed in the Business Plan for the Conservation of Native Black Bass Species in the Southeastern U.S.: A Ten Year Plan (National Fish and Wildlife Foundation 2010). Managers should work with landowners, municipalities, and other government agencies to provide oversight, protection, and restoration of shoal bass habitats in this watershed.
Threats to Suwannee bass habitat and degraded habitats need to be identified and mapped in the Suwannee River watershed, so that a plan could be developed for habitat protection and restoration. Suwannee bass habitat concerns include water quality impairment from urban development, nitrogen loading in springs, agriculture, and unpaved roads. Stream bank destruction by livestock and road crossings can increase sedimentation and degrade Suwannee bass habitat. Water withdrawals may be the most eminent and long term threat to the conservation of Suwannee bass (Warren and Nagid 2008).
Compilation of data and/or identification of habitats if necessary. Start researching/writing hatchery Standard Operating Procedures for the collection and spawning protocols for these species to be prepared for future stocking requests created to help retain wild populations.