By Casey Butler, Maria Cooksey, Gabrielle Renchen and Emily Hutchinson
The Keys Fisheries Research program took to the skies in partnership with the Florida Keys National Marine Sanctuary (hereafter Sanctuary) management team to conduct an aerial survey of vessel use in the Sanctuary. Within the boundaries of the Sanctuary lie nationally significant marine resources, including hundreds of uninhabited Keys, the world’s third largest barrier reef, hard-bottom habitat, seagrass beds, mangrove trees, and more than 6,000 species of marine life. The Florida Keys are home for ~79,000 year-round residents and provide a destination for ~5 million visitors annually. Over the last few decades the number of registered vessels has increased, but the activities of these boaters and how their use of Sanctuary resources have changed over time is not well known. Understanding the patterns of boating activity in the Sanctuary is vital to evaluating the sustainable use of the valuable marine resources of the Sanctuary.
FWRI scientists flew in small planes over the breathtaking waters of the Keys and recorded the type, location, and activity of every boat, personal water craft, kayak, paddleboard, etc. Over the course of 29 flights in 2016, we counted 52,107 boats. The number of boats peaked at nearly 5,000 during the opening days of lobster season and summer holidays. On average, 19% of boats were involved in fishing, 19% were involved in diving, 13% were anchored (with no visible activity), and 9% of boats were at sandbars. Many of the boats we observed (29%) were in transit at the time; however, these boats likely participated in other activities throughout the day. In addition to diving and fishing, other watersports (e.g., kayaking, paddle boarding, jet skiing) and partying at sandbars were popular among the Sanctuary’s visitors and reflect alternative ways in which people enjoy Florida Keys waters. Our research team conducted a similar aerial survey in 1992, and the comparison of vessel use data between 1992 and 2016 shows that there has been a major increase (~400%) in the popularity of watersports (e.g., kayaking, paddle boarding, jet skiing) and partying at sandbars.
The 1992 aerial survey took place prior to the establishment of the Sanctuary Preservation Areas (Figure 1, SPAs). Establishment of the SPAs in 1997 limited consumptive activities within these areas and was intended to reduce conflicts between fishermen and divers. Because these areas were open to fishing during the 1992 aerial survey – including hook-and-line, recreational lobstering and commercial fishing, this allows us to examine how SPA implementation affected stakeholder activity. Currently, we are evaluating changes in dive and fishing boat spatial distributions after the SPAs were established.
Besides providing an outstanding office view for our scientists, this project provided essential information to the Florida Keys National Marine Sanctuary managers regarding vessel use in the Sanctuary and how that use has changed over time, which should aid in future management decisions regarding Sanctuary resources.
The gopher frog is currently being considered for federal protection under the Endangered Species Act. While the gopher frog has experienced serious declines throughout the rest of its range, Florida currently represents a stronghold for the species. Consequently, the gopher frog was delisted as a state-designated Species of Special Concern in January 2017. As a part of the delisting process, a state species action plan was developed for the gopher frog. This action plan calls for the development of a statewide monitoring program for the species. Before the species was delisted, we began a pilot study to increase our understanding of species detection and wetland occupancy rates, as well as to determine the best methodology for a long-term gopher frog monitoring program.
Surveys for the gopher frog monitoring project started in Fall 2015. This project uses seasonal dipnet surveys and frogloggers (automated frog call recorders) to track the status of gopher frogs in 100 wetlands over time. Additional wetlands are also surveyed as time allows to locate new breeding wetlands and track the status of the species in additional known breeding ponds. During FY 2017-18, we surveyed 114 ponds in 22 counties on 29 public or conservation lands for gopher frogs, finding tadpoles in 72 ponds in 21 counties on 24 public lands. These surveys discovered one previously unknown gopher frog breeding pond and observed breeding for the first time in decades in some previously known ponds. Many of the “rediscovered” observations were made in the months following Hurricane Irma, which filled most of the study ponds.
As the data collection phase of this project comes to a close at the end of 2018, in-depth data analyses will begin. Froglogger recordings are already being analyzed using software that recognizes the specific call signature of the species. Unfortunately, this is a very long process due to the large amount of data collected over the three-year project. Dipnet and froglogger data will be analyzed to determine the annual and seasonal patterns of wetland occupancy in each region of the state, as well as the effects of different variables on species detection and wetland occupancy. We will also examine data from both methods to make recommendations about the most efficient sampling methods.
From the vast blackwaters of the Suwannee River to a braided creek in Pensacola to a pin-straight residential canal in the greater Miami area, our NRSA crew has been everywhere, man (cue Johnny Cash). For three months, personnel of the Freshwater Plants Research Program travelled all over Florida to sample a variety of unique ecosystems using multiple standardized sampling techniques. For shallow systems, like Pole Branch Creek in rural Calhoun County, our team of 5-7 samplers packed in all our gear and our backpack electrofishing unit and waded through the sites to complete our surveys. But for deeper and wider systems like the extensive Kissimmee River, we conducted our surveys via two boats loaded down with sampling equipment – one for our habitat crew, the other for our fish crew. On every system we recorded observations about habitat type and condition of the banks. We used specialized equipment and techniques to evaluate characteristics like slope, discharge and fish community assemblage. We also collected samples of water, algae, benthic macroinvertebrates, and fish tissue. All samples and data were recorded and sent to the U.S. Environmental Protection Agency (EPA) for analysis.
The National Rivers and Streams Assessment (NRSA) is a nationwide survey designed by the EPA that takes place in all lower 48 states. Rivers, streams and canals all over the country have been randomly selected for sampling. The resulting data provide an unbiased representation of our nation’s flowing waterways for comparing these systems with others in their region. This is part of a major ongoing effort by the EPA called the National Aquatic Resource Surveys. The purpose of these surveys is to assess the conditions of our nation’s waterbodies and to track them over time. NRSA is just one aspect of the big picture and takes place over two consecutive summers, occurring every 5 years. This season was the first of their 2018-19 sampling event.
As our season is wrapping up, we proudly look back at all we have learned, experienced, and accomplished this summer. This project has provided us the opportunity to use new tools and techniques, such as densiometers to measure canopy coverage and stadia rods or sonar to document channel depths and substrate type along thalwegs. It has also encouraged us to connect with other FWC offices, Water Management District personnel, and local land owners or managers. With the help of their local knowledge and expertise we have successfully completed half of the selected survey sites during this first year. We look forward to continuing this work next summer as we prepare to tackle the rest of our sites which include larger river ecosystems such as the Escambia and Apalachicola Rivers.
Our NRSA Sampling Crew included: Jamie Richardson, Kyle Miller, Emily McPartlin, Amanda Christensen (volunteer), Greg Knothe, Siobhan Gorham, & Craig Mallison. A special thanks to: Travis Tuten, John Knight, Kate Harriger, Chelsea Myles-McBurney, Kayla Smith, & Jason O’Connor for their assistance.
East Lake Tohopekaliga (ELT) is a 4843-ha mesotrophic lake located in the Kissimmee Chain of Lakes in Osceola County. In the 1960s, water control structures and canals were constructed in the Kissimmee Chain for flood control. These structures stabilized water levels in ELT and the other lakes in the chain, reducing the magnitude of seasonal water level fluctuations. The water level stabilization eventually led to increased accumulation of organic material and excessive growth of invasive aquatic plants that contributed to an accelerated rate of lake succession in ELT. The vast monocultures of invasive aquatic vegetation (e.g., torpedograss Panicum repens and cattails Typha sp.) growing within the littoral zone created and trapped additional organic material and ultimately resulted in the formation and expansion of floating tussocks. Extremely dense vegetation and tussocks resulted in degraded fish and wildlife habitat and limited recreational access for homeowners, anglers and boaters.
A lake drawdown and subsequent habitat restoration is set to begin on October 1, 2019. It will be a collaborative effort by FWC’s Aquatic Habitat Restoration/Enhancement subsection (habitat restoration), the South Florida Water Management District (water level regulation schedule changes), and the United States Army Corps of Engineers (overseeing drawdown). Once ELT has been dewatered, FWC biologists will utilize a combination of herbicide treatments and prescribed burning as well as mechanical removal of woody vegetation, tussocks and organic sediment to restore the littoral zone habitat (Figure 1). Herbicide treatments and prescribed burning will be used to control/remove monotypic stands of invasive vegetation (e.g., torpedograss and cattails) along the northern and western shores. Mechanical removal of woody vegetation (e.g., willows Salix sp. and water primrose Ludwigia spp.), tussocks and organic sediments will be completed along the eastern shore. Two areas along the southern shore will not receive any treatment and will be considered control areas. Once the habitat restoration is complete, ELT will be refilled via precipitation during the summer of 2020.
To evaluate the effects of the restoration, fisheries biologists are assessing potential changes in fish community composition, water quality, and habitat structure/composition in shallow (< 2 feet deep) littoral habitats pre- and post-restoration. Researchers are deploying mini-fyke nets (MFNs) and dissolved oxygen (DO) logging sondes to sample the fish communities and DO regimes, respectively, in each treatment/control area (18 sites per area, 90 sites per year). Qualitative assessments of aquatic vegetation and quantitative assessments of organic sediment depth are also completed at each sampling site. Pre-restoration sampling will continue until the restoration begins in 2019 and post-restoration sampling will be conducted for at least two years after ELT has refilled.
In 2016, the first year of pre-restoration sampling, a total of 4,847 fish comprising 26 species were captured across all successfully sampled sites (n = 88). Habitat data from 2016 indicated that the eastern shore (Mechanical Removal and Scraping area; Figure 1) had significantly deeper organic sediments and significantly lower aquatic plant density than the other four treatment/control areas of ELT. The second year of pre-restoration sampling was scheduled for 2017 but was cancelled because precipitation from Hurricane Irma resulted in water levels that were too high to effectively sample the littoral zone. Results from this study will help researchers and managers understand how habitat restorations influence shallow water fish communities, water quality, and habitat structure/composition. Understanding the effects that different restoration actions have on those parameters will provide managers with an idea of how future restorative efforts may influence the ecology of littoral habitats in lakes.
As a scientific institution, it is important that FWRI communicates what we’re doing real-time and as transparently as possible to the public. One of the more effective tools we have to do that is our digital annual report which gives you an overview of the Institute and also highlights specific research work that ultimately is going to benefit wise management of our natural resources. We encourage you to explore our interactive annual report, found here: fwcresearch.com.
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FWC Research: Our Mission
Management decisions must be driven by sound scientific information. Planning and conducting research to provide this information is the core of the Fish and Wildlife Research Institute’s (FWRI) mission.
Manatee Rescue, Vilano Beach FWC and St. Johns County Sheriff’s Office responded to a manatee stranding in Vilano Beach. The manatee was showing signs of cold-stress syndrome and transported for rehabilitation to the Jacksonville Zoo and Gardens.
The reddish egret (Egretta rufescens) is North America’s rarest heron and is state-listed as Threatened in Florida. In 2016 we visited 305 coastal islands during the first statewide survey of the species to document its distribution, estimate Florida’s population size, and learn more about its nest-site selection patterns. In 2017 we attended to the less glamorous side of our work – sitting at our desks, crunching numbers and writing.
Reddish egrets were primarily concentrated in four areas of Florida: in and near Merritt Island National Wildlife Refuge, Florida Bay, the Lower Keys, and the Tampa Bay area south to Marco Island. The species has continued to slowly expand northward on the Gulf coast, with nesting occurring in Cedar Keys National Wildlife Refuge. There were an estimated 480 (95% CI: 375–606) nesting pairs at the 58 sites where birds we found birds. The largest colony we found had 23 nesting pairs, which is fewer than the three largest colonies documented in Florida Bay during 1978. Half of all colonies had 3 or fewer pairs.
Reddish egret foraging behavior can be something of a spectacle as birds move throughout tidal flats and other shallow estuarine waters in a graceful, high-energy pursuit of prey. Foraging habitat is probably the largest limiting factor for reddish egret populations, and our nest-site selection analysis confirmed that it was the most substantial predictor of occupancy and abundance of nesting reddish egrets. These results confirm the importance of incorporating foraging habitat into our restoration planning and highlight the need to understand how the shallow flats upon which reddish egrets rely will be affected by sea-level rise.
The photo accompanying this article was taken by Anne Macias. Anne was a retiree in Bonita Springs and a strong advocate for Florida’s birds. She took great pride in the colony of nesting wading birds in her neighborhood and raised awareness of their importance within her community. Our jobs are made that much easier by people like Anne. Anne unfortunately passed away earlier this year and will be deeply missed.
The U.S. Army Corps of Engineers (USACE) in cooperation with the Jacksonville Port Authority (JaxPort) have conducted a comprehensive economic, engineering and environmental study to examine the effects of increasing the depth of the existing Federally-maintained shipping channel in the lower St. Johns River (LSJR) from the current depth of 40-feet to a maximum depth of 47-feet between the mouth (Mayport, Florida) and river mile 13 (Figure 1). The channel deepening will allow access of larger vessels (Panamax and New Panamax classes) to deliver cargo to existing JaxPort terminals around Blount Island. The initial phase of dredging began in February 2018.
As part of the project evaluation, computer modeling scenarios were completed on the potential effects that the channel deepening might have on water quality, circulation patterns, salinity gradients, and a variety of ecological components (wetland vegetation, submerged aquatic vegetation, benthos, plankton, and nekton [macroinvertebrates and fish]) in the LSJR. Over 100 nekton species have been documented by the Fisheries-Independent Monitoring (FIM) program at the Florida Fish and Wildlife Conservation Commission’s (FWC) Fish and Wildlife Research Institute (FWRI) as using the estuarine portion of the LSJR and many of the species represent important commercial and recreational fisheries. During the evaluation, there were two specific areas the FIM program felt were in need of consideration with respect to nekton: 1) the potential effects of salinity changes on the spawning success, recruitment, and population dynamics of important recreational, commercial, and forage nekton and, 2) the potential effects of salinity changes on critical nekton habitat within the LSJR estuary.
Within the estuary, channel deepening has the potential to affect salinity and water quality gradients, most likely by shifting distributions in these gradients within the estuary. These shifts may affect spawning and nursery habitats and ultimately influence the reproductive and recruitment success of estuarine-dependent nekton. Of particular concern are the tidal tributaries in the LSJR near and upriver from the area being dredged. These tributaries between river miles 15 and 30 (Trout, Arlington, and Ortega rivers; Figure 1) and the estuarine section between Julington Creek (river mile 40) and Palatka (river mile 82; Figure 2) are highly influenced by freshwater inflow and generally have lower salinities than other portions of the LSJR estuary. The freshwater influence in these sections of the LSJR provides low salinity habitats that many estuarine and marine nekton require during their early life history stages. Previously collected data in these tributaries suggests that many recreationally and commercially important estuarine-dependent species (i.e. members of the Sciaenidae family [i.e. red drum, spotted seatrout, atlantic croaker, spot], white shrimp, blue crab, and mullet) utilize these habitats and that these areas likely represent critical habitats for maintaining healthy stocks of these species in the LSJR estuary and adjacent coastal waters. Also of concern with regards to potential changes in salinity would be impacts on resident freshwater species, especially within the Trout, Arlington, and Ortega rivers. Salinity increases could decrease the availability of freshwater habitat, thereby reducing the abundance of freshwater species in these tidal tributaries. The Mill Cove area, although freshwater inflow is limited, is also of concern because the salinity modeling done by the Corps identified it as the area most likely to experience the greatest salinity changes. Young-of-the-year (YOY) and juveniles from numerous nekton species utilize this habitat during ingress, egress, and as nursery habitats.
Since 2001, the Fisheries-Independent Monitoring (FIM) program has monitored nekton abundance and distribution in the LSJR estuary downstream of Julington Creek (river mile 40; Figure 1). Between 2005 and 2016, funding from the St. Johns River Water Management District (SJRWMD) enabled the FIM program to extend sampling upriver from Julington Creek (river mile 40) to Palatka (river mile 82; Figure 2). The FIM program uses a multi-gear approach in a stratified-random sampling design to collect data on nekton from a wide range of habitats and life history stages. Water chemistry, habitat, and physical parameters are recorded at each sampling site. The FIM program sampling was designed to monitor fishery resources in the estuary as a whole and, therefore, does not include individual tributaries as specific sampling strata, but instead includes them as portions of larger geographic strata. The spatial extent of the tributaries is very small compared to that of the entire estuary, so the individual tributaries are often underrepresented and inconsistently sampled in the current sampling design. Data from the existing FIM program design, therefore, are not sufficient to assess changes in nekton composition and abundance due to perturbations, such as a channel deepening, within specific areas (tidal tributaries and coves). Estimating impacts to the nekton assemblage from the channel deepening in these areas requires a sampling strategy that focuses on these specific areas of the LSJR estuary.
To gain a better understanding of the relationships between channel deepening, salinity, water quality, water flow, estuarine habitats, and the abundance of estuarine-dependent and freshwater-resident species that inhabit the identified areas of the LSJR, the FIM program and the USACE have developed a long-term monitoring project to determine the impact of the dredging activities on the spatial distribution and abundance of nekton within the LSJR. The long-term monthly sampling, which began in May 2017, and has the potential to run through 2035 (funding dependent), will increase the resolution of nekton data within the identified tidal tributaries (Trout, Arlington, and Ortega rivers) and the Mill Cove area (Figure 1) as well as continue the long-term sampling upstream of Julington Creek (Figure 2), for which funding from the SJRWMD was withdrawn at the end of 2016. This project will allow for the assessment of the effects of channel deepening on nekton assemblages in these critical LSJR estuarine habitats.
FWRI HAB and molluscan fisheries groups are collaborating on a one-year project funded by the Tampa Bay Estuary Program to investigate if the creation of shellfish nurseries as part of restoration efforts could have the added benefit of interfering with Pyrodinium bahamense bloom development. P. bahamense is a toxic dinoflagellate that forms high biomass blooms in Old Tampa Bay, the Indian River Lagoon (IRL), and other systems in Florida each summer. These blooms can cause shellfish harvesting area closures due to presence of paralytic shellfish poisoning (PSP) toxins (http://myfwc.com/media/3323422/Pyrodinium-bahamense-factsheet.pdf).
As filter feeders, bivalves can clear particles from over a liter of water every hour for each gram of dry body weight when feeding optimally. Clams can have up to ~ 5 grams of tissue, so that’s a lot of algae consumption! The goal of this research project will be to investigate how well targeted bivalve molluscs can feed on toxic P. bahamense. Molluscs that consume P. bahamense become toxic and cannot be consumed by humans, but they still play a critical role in healthy estuaries. We are conducting our first set of experiments with hard clams (Mercenaria spp.), and the next focus will be eastern oysters (Crassostrea virginica). If successful, these experiments may be scaled up to mesocosms once ideal species are identified.
Gulf Reef Fish Survey Improves Fisheries Management
Since April 2015, the Gulf Reef Fish Survey (GRFS), with the crucial support of recreational anglers of Florida, has provided timely and precise data to state and federal agencies that are responsible for managing reef fish. By signing up for the survey, anglers are eligible to receive a questionnaire about recent fishing activity. Each month, angler responses from the survey are used to estimate the number of recreational trips taken on the west coast of Florida to fish for Gulf reef fish species. By working collaboratively with NOAA Fisheries, the Gulf Reef Fish Survey produces data that is complimentary with the existing Marine Recreational Informational Program. We are only as strong as our weakest data set, and with the help of the recreational anglers of Florida, we have gathered more data than would have been possible with just the FWC. We thank our angling contributors for the success and continued success of the Gulf Reef Fish Survey.
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Learn about the FWC’s Charlotte Harbor Field Office, which hosts Fisheries-Independent Monitoring staff, manatee researchers and rescuers, as well as staff from the Fisheries-Dependent Monitoring program.
Modern methods of remote acquisition, image data processing and modeling have presented new opportunities to research and better understand the complexities of seagrass ecology. The high spatial and spectral resolution information provided by modern airborne sensors such as satellite imagery presents opportunities to monitor subtle yet ecologically important changes in seagrass abundance.
In 2016, FWRI’s Center for Spatial Analysis received funds from FDEP’s Coastal Management Program to quantify long term changes in seagrass cover within the Indian River Lagoon (IRL) system. The demand for improved mapping and monitoring submerged resources in the IRL was driven, in part, by unprecedented losses in seagrass resulting from several algal ‘super bloom’ events starting in 2011.
The study employed a supervised classification method to map seagrass percent cover by relating spectral values in the satellite image to percent cover observations collected at fixed station transects by the St. John’s River Water Management District (SJRWMD) and the Ecological Program at NASA’s Kennedy Space Center.
Results indicated considerable declines in percent cover between 2010 and 2016. The extent of seagrass loss, however, was spatially and temporally variable throughout the lagoon system. Throughout the study area, seagrass cover was highest in 2010 and 2011 just prior to the 2011 super bloom and then declined considerably in 2012. In several areas, there were signs of recovery with increased percent cover in 2013, however, seagrass declined in 2015 and was nearly absent in most areas by 2016.
Declines in seagrass percent cover were highest in the southern portion of the Indian River Lagoon and throughout the Banana River with as much as 100% loss of the densest seagrass (75-100% cover). While complete loss of seagrass was observed by 2015 and 2016 in some areas, there was a general pattern of “thinning” in seagrass percent cover throughout the study area. This pattern is characterized by replacement of dense seagrass (>50% cover) with sparse, low density seagrass (<25% cover). The extent of this variation was not detectable from small scale in situ transect monitoring nor from temporally limited aerial photography. Results of the study emphasized the need for evaluating landscape-scale variability in seagrass percent cover using a variety of remote sensing technologies.
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