All posts by flmarineresearch

Fish Feeding Ecology (Gut) Lab

by Brittany Hall and Gabriel Ramos-Tafur

Scientists in the gut lab process stomachs from fish of all sizes, collected both inshore and offshore, in order to compile comprehensive diet information that is used in various models.  Digestion is the biggest obstacle when processing these guts.  Our main goal is to identify everything to the lowest taxonomic level possible (this includes amphipods, shrimps, crabs, mysids, and the list goes on and on), and generally we are looking for identifiable parts that are more resistant to digestion.  Crabs and shrimps have external hard parts that are a little more resistant to digestion, but fish have fewer of these external parts.  Most of the time, things like color, fin-ray counts, pores, and scales are needed to work your way through an identification key, but when a fish is a prey item, these clues are often missing.  One of the last parts of a fish to disappear during digestion is its jaws, and we often use jaws to identify fish in stomach contents.  Careful study has revealed that jaws are like fingerprints – very distinct teeth and bones that allow us to identify many prey species to family and even species.

Because there are currently no identification keys for the jaws of fish species found Gulf of Mexico and Tampa Bay, scientists have been diligently developing a reference key to be used to identify digested fish prey.   This task involves removing the tissues from the jaw bones of fresh specimens, staining the jaws, taking pictures, and writing descriptions of each intricate bone.  Although tedious, much headway has been made, and results of this one of a kind project were presented at the upcoming national meeting of the American Fisheries Society in August 2015!

Scanning the Ocean Floor for Fish Habitat

by Eric Weather

Maximizing the Efficiency of Reef Fish Surveys Through IncorporaThe Gulf of Mexico benthic habitat can be summarized as a mosaic of sand with limestone rock outcroppings (reefs).  These reefs facilitate the settlement and growth of a wide variety of benthic organisms including corals, sponges and crustaceans.  They also support a diverse fish community from tiny blennies and gobies to commercially and recreationally important groupers and snappers.  The Fisheries-Independent Monitoring (FIM) program in cooperation with the National Marine Fisheries Service (NMFS) conducts annual fisheries monitoring on these reef habitats to provide data for single species and ecosystem-based management initiatives.  In 2009, the FIM program implemented the use of side-scan sonar to identify and classify the benthic habitats in the eastern Gulf of Mexico between 10 m and 110 m deep.  These sonars are towed behind a survey vessel and are equipped with two side-facing transducers that generate and receive sound signals.  When a signal is generated it propagates through the water column and reflects off the seafloor and then back to the transducer.  The intensity at which the return signal is received is interpreted into an image that is deciphered by a trained survey technician.  The configuration of the transducers on the sonar allows the sound signal to ensonify a very wide swath of the seafloor (up to 300 m) at one time.  As the survey vessel moves through the water, a streaming image of the seafloor is generated, as depicted in the video.  When rocky outcrops are identified by a survey technician they are given a habitat category based on their structure and complexity and become the basis for the NMFS/FIM reef-fish survey.  Additionally, these data are used by regional geologists, cartographers and other biologists to help answer a wide variety of research related questions regarding the benthic habitats of the eastern Gulf of Mexico.

A Talk with Dr. Susan Lowerre-Barbieri

by Michelle Kerr and Bradley Walker

Dr. Susan Lowerre-Barbieri is clearly passionate about two things, her family and her research. During our interview, Sue first talked about what motivated her to pursue a career as a fisheries biologist. She’s led many research projects throughout her career, and one study she discussed was a three-year red drum spawning study that took place in the Gulf of Mexico.


Highlighting habitat restoration

by Bradley Walker

One of our upland habitat research flagship programs, the Native Groundcover Restoration (NGCR) Program, began working on a restoration site in Three Lakes Wildlife Management Area in 2008.
The Native Groundcover Restoration Program is a collaborative effort between FWRI and the Division of Habitat and Species Conservation – specifically the Wildlife Management Area system.

We recently began a new project with our upland habitat research section to highlight their habitat restoration work at various Wildlife Management Areas around the state. Our first habitat restoration feature is an ongoing project at Three Lakes Wildlife Management Area in Osceola County. The Native Groundcover Restoration program began working at this restoration site in 2005, and since then it has transformed from an “improved pasture” with no value as wildlife habitat to a site filled with native plants and groundcover that provide food and cover for many native wildlife species. Our Flickr set breaks down the restoration process, and includes some great photos taken at the Three Lakes site:


Assessing Vegetation at Blue Spring State Park

by Craig Mallison and Siobhan Gorham

Aquatic habitat types, aerial herbicide treatment areas, and study plots in the lagoon and marsh at Blue Spring State Park, October 2014.

Blue Spring State Park in Volusia County has been open to the public as a state park since 1972 and includes Blue Spring, the largest single spring on the St. Johns River system. In addition to the spring, the park encompasses a spring run and a lagoon with an adjacent marsh. Due to extended drought, infrequent fire, and fluctuating water levels, the marsh habitat has degraded over time with advancement of woody vegetation including willow, red maple, and buttonbush. The Aquatic Habitat Restoration and Enhancement Section (AHRE), within FWC’s Division of Habitat and Species Conservation, teamed with the Florida Department of Natural Resources to initiate a project to control the encroaching woody plants and restore herbaceous marsh habitat. They contacted the Freshwater Plants Research project to evaluate the effectiveness of herbicide treatments and prescribed fire in restoring quality habitat in the marsh.

We will compare composition of woody vegetation and herbaceous marsh in treated areas and non-treated (control) areas over time. Pre-treatment sampling and aerial herbicide treatments were completed in October 2014. We used aerial photography, acquired by AHRE, along with field survey data to map the plant communities within the entire study area. We established three one-acre sampling plots within each treatment group. Initial results documented 80 percent coverage of woody vegetation and 20 percent coverage of herbaceous marsh within treated and control plots. Sampling will be completed annually for three years to evaluate changes in community composition. The management objectives of the herbicide treatment are to reduce woody vegetation by 70 percent and to increase herbaceous marsh by 50 percent. This would establish plant communities that can be maintained with a prescribed fire regime to sustain quality freshwater marsh habitat into the future.

Bottom-Up Conservation – Can Groundcover Restoration Benefit the Florida Panther?

 by Samantha Baraoidan

Panther print on ground
Florida panther track on Okaloacoochee Slough Wildlife Management Area.

December marked the end of the field season for one of Upland Habitat’s flagship programs, the Native Groundcover Restoration (NGCR) Program (more information here). For those unfamiliar with NGCR, it is a collaborative effort between FWRI and the Division of Habitat and Species Conservation – specifically the Wildlife Management Area (WMA) system. The goal is to restore areas with low or no value as wildlife habitat, such as relict agricultural fields, clear cuts, or improved pastures. The restoration goals are mainly pine flatwoods and sandhills. To date, we have restored almost 2,500 acres on 18 different management areas. Okaloacoochee Slough WMA (OK Slough) in Hendry County contains some of our longest-running NGCR sites. This season we sampled three sites-in-progress at OK Slough. While breaking for water at the swamp buggy, we noticed some Florida panther tracks in the road (see photo). OK Slough manager, Jean McCollom, informed us that we were in close proximity to the den site of Florida Panther 110, a female known to have mothered several litters of kittens. We frequently observe white-tailed deer and wild turkeys on our NGCR sites at OK Slough, and the thick cover of native bunchgrasses is ideal for small mammals, such as cotton rats and marsh rabbits. All of these are common prey items for female panthers and their kittens. Jean hypothesized that Florida panther 110 might be utilizing our NGCR site as a hunting ground. That particular site began restoration in 2005, and 110 had been denning there since 2010. While incidental observations such as this one are not proof that panthers are utilizing our fields, they do provide clues to the ways that NGCR might be benefiting all native wildlife, from the smallest invertebrates to top-level carnivores. In the future, we hope to implement formal wildlife monitoring programs on NGCR sites in an effort to better understand how habitat restoration helps native species.

Integrating habitat mapping into Florida’s Freshwater Fisheries Long Term Monitoring Program

by Kevin Johnson

Though not a waterbody part of the LTM Program, this picture displays a finalized submersed vegetation coverage and density raster heat map for Kings Bay, Crystal River, Florida. Included is the point-intercept data for eelgrass Vallisneria americana, closed circles represent point-intercepts where eelgrass was found.

Freshwater Fisheries Long Term Monitoring (LTM) Program began in 2006 with the intent to obtain data to be used by managers to determine trends in sportfish abundance, species composition, mortality, growth, size structure, and utilization by anglers for Florida’s important freshwater fisheries.  The LTM Program has 30 core lakes that are sampled annually for these metrics.  With this program in place, there was a growing need to develop an efficient method of collecting habitat information in these lakes so that habitat quality and quantity could be monitored over time.

Therefore, our objective was to develop sampling protocols that would provide accurate lake-wide estimates of the percent of area covered and percent volume infested with submersed and emergent vegetation in lakes that are part of the LTM Program.  After investigating different techniques used for sampling aquatic vegetation, we determined that two methods of remote sensing fit our objective.  These include hydroacoustic sensing for mapping submersed vegetation and the interpretation of satellite imagery for mapping emergent vegetation.

Hydroacoustic sensing for mapping submersed vegetation will entail traversing sampling transects with a boat-mounted Lowrance HDS sonar unit.  Point-intercept sampling along transects will also take place to determine species occurrence within a lake with the use of a vegetation rake.  Transect spacing will be a function of point-intercept intensity, with the program’s largest lakes having a spacing of 285 meters which is equivalent to 1 point per 20 lake acres.  Recorded Lowrance sonar logs will be uploaded to CiBioBase, a company that provides rapid automated web-based processing software which uses a series of algorithms to interpolate and extrapolate raw acoustic sonar data into whole-lake submersed vegetation coverage and density raster heat maps.  These raster maps will then be converted into ArcGIS raster maps in order to add point-intercept data.

Interpretation of satellite imagery for mapping emergent vegetation uses Landsat images to delineate the emergent vegetation boundary of a lake with ArcGIS software.

With sampling protocols developed, annual mapping efforts will take place during the peak growing season, beginning summer 2015.

The Economic Value of Florida Youth Conservation Centers Network (FYCCN)

by Joonghyun “Cheetos” Hwang

Website screenshotFYCCN is a newly developed program that is jointly sponsored by FWC and the Wildlife Foundation of Florida.  The program is designed to encourage Florida’s children to participate in traditional outdoor recreation by teaching them how to safely enjoy fish and wildlife activities and to educate them on the value of conservation to inspire the next generation to care about conservation.  The program is being implemented though partnerships with schools, communities, youth organizations, volunteers, land owners, and donors, and the success of the program heavily relies on the engagement of the partners.  FWC wishes to better understand the value of the program to address its importance and to guide its direction.

Since 2009, FWC has been asking hunting or fishing license buyers if they would willingly contribute money to support FYCCN as part of their purchases.  The license purchasers select the donation amount from five options, and the amount selected is added to the total license purchase fees.

The donation history is available from the Office of Licensing and Permitting, and it will allow me to estimate the mean willingness to donate for FYCCN.  I will then derive the aggregated economic value of the program to fishers and hunters in Florida from the mean value, and this economic information will provide FWC leadership a useful guidance for decision making.

Testing mercury levels in Florida’s marine fishes

by Derek Tremain and Doug Adams

Fish dissection
Removing muscle tissue from a Spanish mackerel for mercury testing.

Mercury, a toxic metallic element, has been shown to bioaccumulate in fish tissue, and if humans eat contaminated fish, they can potentially consume significant levels of mercury. Testing fish flesh for mercury content began in 1989, the same year the Fisheries-Independent Monitoring (FIM) program began and continues today. In the early years, fish samples were sent to the Florida Department of Environmental Protection for testing, but in 2006 the FIM program purchased a new state-of-the-art instrument (DMA-80 Direct Mercury Analyzer) that now allows fisheries scientists from FIM’s Indian River field laboratory to analyze more fish samples for mercury content and reduce the processing time. To date, FIM staff have collected, processed, and documented mercury information from more than 80,000 individual fish yielding almost 300 species, all of which were collected through the statewide sampling program.  These individual specimens represent all major groups from primary consumers and prey species to apex predators at the top of the food web and include many popular sport fish such as seatrout, red drum, snappers, groupers, common snook, mackerels, and tunas to name just a few. The majority of marine and estuarine fishes examined contained low levels of mercury, but several important recreational and commercial fishery species such as sharks, tunas, mackerels, and cobia have shown elevated levels. Many of the samples processed by FIM scientists are provided to the Florida Department of Health (FDOH) to develop and update fish consumption advisories. These advisories provide specific guidelines regarding Florida marine fishes, and recent updates can be found on the FDOH website.

The venom in lionfish spines remains active, so fisherman are urged to clean their catch with an abundance of caution. Photo by John Stevely Florida Sea Grant Extension Emeritus

One species of recent interest, with almost no previous mercury information available, is the invasive Indo-Pacific lionfish (Pterois spp). Given the recent management strategy to encourage divers and fishers to harvest and eat this species, FIM scientists analyzed mercury levels in this species from throughout Florida’s coastal waters and published the research in a recent paper. The results suggest that lionfish contain very low levels of mercury, similar to species that currently fall under the FDOHs least restrictive consumption guidelines. However, lionfish populations are in the relatively early stages of establishment in Florida and larger and older individuals, with potentially higher mercury levels, will likely become available to consumers. Therefore, a routine part of the FIM program is to continue to monitor this species, and others, to identify any changes in mercury levels that may occur over time.

In the past few months, FIM staff and partners at the Florida Department of Environmental Protection have analyzed nearly 3,000 samples that include many fishery species such as mangrove snapper, red snapper, red porgy, common snook, black sea bass, spotted seatrout, and red drum. Future research relating mercury levels to fish age, feeding ecology, and the trophic structure (food web) of Florida’s marine and estuarine ecosystems will help us better understand concentrations of this element in marine fishes.