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s D WaterWorks IFAS Newsletter of the UF/IFAS Department of and Aquatic Sciences October 2007

months by Dr. Denise Petty will help determine if environmental diseases or disease pathogens are present. In addition, low larval survival has been reported in hellfish quaculture Florida hatcheries in recent years and S A has impacted clam seed production. Therefore, site visits by Dr. Petty will esearch xtension include assessment of hatchery protocols R & E and health of larvae and post-set seed. The by: Leslie Sturmer goal is to reveal practices that are limiting to seed production.

he Shellfish Extension the FAU Harbor Branch Oceanographic roduction Technology Diversifying TProgram (SAEP) works with research Institution and will be evaluated under Pthe hard clam culture industry by faculty in the Department of Fisheries and commercial conditions during 2008-09. developing farming technology and Aquatic Sciences (FAS) to develop and markets for other bivalve species would implement applied research and extension ater Quality Monitoring SAEP increase economic stability and growth. educational projects for the state’s shellfish Whas developed a partnership with Florida Sea Grant is funding a project aquaculture industry. In collaboration with federal and state agriculture agencies for where faculty from SAEP, FAS, Food and industry, institutional, and agency stake continued operation of water quality and Resource Economics Department and holders, these projects are focused on four weather monitoring stations to provide FAU Harbor Branch will develop and major areas: (1) genetic stock improvement; data for a decision support tool used by demonstrate biological and technical (2) water quality monitoring; (3) animal the clam industry. Currently, stations procedures for spawning and culturing the health and (4) production technologies. are located at 7 high-density lease areas sunray venus clam Macrocallista nimbosa. in 5 coastal counties. These stations The sunray venus is an attractive venerid enetic Stock Improvement Using provide timely continuous information clam distributed from South Carolina to Gfederal and state funds, SAEP and to clam growers, allowing them to make Florida and the Gulf states. Commercial FAS faculty conduct applied research informed management decisions based on fishermen targeted the large 4-7 inch to help develop a hardier clam strain temperature and salinity measurements. clam in the late 1960s off the northwest through breeding techniques that improve This program, however, does not allow for Florida coast for the chowder market but survival during prolonged hot summers. A an in-depth understanding of the influence the erratic size of the grounds combination of high water temperature, of temperature on clam production. Smaller precluded large-scale exploitation of this reduced oxygen and high clam data loggers (that can fit inside clam bags) . Recent growth experiments, using metabolism may contribute to increasingly were recently purchased with Hatch marked individuals, suggest that these high summer mortalities observed in funding, and will allow for greater spatial popular clams can attain a length of 3 Florida hard clams. A Florida Sea Grant- resolution and broader data coverage. to 12 inches in just 12 months, similar funded project is evaluating the use of This summer clam growers are deploying to market size of hard clams in Florida. triploidy to enhance clam production. these units at multiple lease sites so that The existence of a prior fishery, market Results from field trials conducted with temperature variability can be related potential and growth rate, along with it industry partners and laboratory studies to water depth, substrate characteristics, being a native species, make the sunray conducted by Dr. Shirley Baker and her currents and other parameters. venus a logical choice as a new species graduate students will determine if triploid to diversify the shellfish aquaculture clams have greater resistance to summer nimal Health In 2003, FAS and industry. Broodstock have been selected environmental stressors through reduced ASAEP faculty conducted a preliminary and spawned and the juvenilles are being gametogenesis. The use of hybrids between health assessment of cultured clams by culutred by industry parnters in land-based the hard clam Mercenaria mercenaria and examining samples from several growing nurseries and commercial leases. southern quahog clam M. campechiensis areas. No serious disease-causing agents for increasing survival and production were detected. However, there is a Leslie Sturmer is a multi-county shellfish is being examined with USDA special concern regarding the health of stocks as aquaculture extension agent and faculty member in the Department of Fisheries research grant funding procured through growers report crop losses during summer. and Aquatic Sciences the efforts of the Cedar Key Aquaculture Pathology may be exacerbated by stressors Association. Triplicate families of each, or high stocking densities. With Hatch Contact the Author: and their reciprocal hybrids, are being funding, a more thorough examination of [email protected] or (352) 543-5057 produced this fall by Dr. John Scarpa at stocks prior, during and after the summer

1 Thermal Tolerance Student Spotlight of Triploid Clams The northern hard clam (Mercenaria more susceptible to mercenaria) has been a popular poor conditions. item for many years, and is an important aquaculture crop along the eastern Clam farmers met By: Elise Hoover seaboard. Aquaculture of the northern with scientists, hard clam became prevalent on the managers and west coast of Florida in the 1990s after extension agents to a retraining program was initiated for discuss concerns fishermen impacted by poor oyster harvests with the high clam mortalities. Triploidy Is triploidy a potential solution for Florida’s and Florida’s gillnet ban. Clam farming has was suggested as a possible solution, since hard clam industry? been a success story for Florida’s coastal triploid bivalves have been shown to have reduced reproduction, which could then Based on the results of these laboratory be realized in additional energy stores challenges, probably not. However, available during summer months. Hard additional on-going research relating to this clams are diploid in nature, meaning project, including scope for growth studies they have 2 sets of chromosomes per cell, and larger-scale field experiments, will whereas triploid organisms have three sets provide additional information and perhaps of chromosomes. Triploid and diploid a modified answer to that question. hard clams were produced at FAU Harbor Branch Oceanographic Institution.

As part of my master’s thesis, I conducted laboratory experiments to assess the value of triploidy for hard clam aquaculture. I challenged two sizes of clams to a range of In this photo, Elise is examining a group of triploid water quality conditions and assessed their clams that were grown at a particular water temperature for their viability. survival. I tested growout-size seed clams (20 mm average shell-length) and pasta- fishermen, where the warm plankton-rich size clams (46 mm average shell-length) waters allow clams to reach market size which represent the two size classes that in 12 to 18 months, faster than other areas are typically in the field during summer along the east coast. With a net profit of months. Groups of clams were exposed 10.7 million dollars in 2005, the Northern to 14 different treatments, representing the A large number of tanks were used in a controlled hard clam is one of the most economically range of salinity, temperature and dissolved laboratory setting to allow exposure of clams to a important aquaculture species in Florida’s oxygen conditions to which clams might wide range of water temperatures. marine waters. be exposed during summer in Florida. Despite the apparent lack of higher survival In recent years, clam farmers on the West I found that there was only one treatment in rates under adverse conditions, triploidy coast have reported lower than average which triploids survived in greater numbers does have other benefits. Sterility, or lack survival and crop losses during the long than diploids. Pasta-size triploid hard of reproductive activity, would be beneficial hot summers. This has been attributed to clams performed well at high temperatures in areas interested in containment of higher than average water temperatures and low dissolved oxygen, while diploid non-native species for aquaculture use. combined with fluctuating salinities, low hard clams had lower survival. Growout- In addition, sterility has been found to dissolved oxygen levels, and potentially size diploid clams performed better or the correlate with higher glycogen content in lower food availability. In addition to same as triploids in all of the experimental triploid oysters, giving them a sweeter taste. stressful environmental conditions, the conditions, suggesting there may be a This may also be the case for clams. hard clam loses a significant amount of disadvantage to triploidy at a smaller size. energy reserves to reproductive activity Elise is a Master’s student and her advisor during the spring in Florida, leaving them is Dr. Shirley Baker.

2 Design & Management of Reefs for Fisheries Faculty Focus interest in fisheries, conservation and eco- Student tourism applications. There were about 100 applications & Faculty By: William Seaman for 28 openings. The course News was held under the auspices of the International Centre Dr. Tom Frazer for Advanced Mediterranean was selected Agronomic Studies, through to receive a Design and Management of Artificial Reefs for its Mediterranean Agronomic Institute of University Fisheries was the title of a European Union- Zaragoza. The Institute offers both short of Florida Research Foundation funded short course held in May 2007, as the courses and graduate residential programs in Professorship Award. The first of its kind in the world. subjects including aquaculture. three-year professorship recognizes faculty who have Attendees from various natural resource-related Dr. William Seaman is Professor Emeritus established a distinguished ministries, academia and businesses came to in FAS. For much of his career, he has been record of research and Zaragoza, Spain from several countries of the involved with developing and extending the scholarship at UF. Mediterranean Sea basin, but also from as far scientific basis for artificial reef technology, Nikki Dix and away as Malaysia, Mexico and Norway. and continues this effort as part of broader, Zy Biesinger, more recent activities related to stewardship both PhD One of the invited organizers and lecturers was and sustainability of earth and sea resources students in FAS, Bill Seaman of the FAS faculty, who delivered globally. He is an invited speaker for the 2008 were recognized for their presentations on matching reef to World Fisheries Congress. research in marine science ecosystem management and on reef planning at the UF capital campaign concepts and practices. Major topics of the Contact the author: Gala Kickoff Event at the O’Connell Center. course included the ecology of artificial reefs, Email: [email protected]

their design and evaluation, and role in fishery Carl Walters management, with theory balanced by a week- ty of joins us again si Fl long case study and independent reef system r ries o this fall, teaching e she & A r Fi q v f u i planning exercises. i o a d an advanced t t i c n n a

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s While artificial reef-related research and D development may have peaked in some fisheries experts at state IFAS and federal agencies. Carl nations, in others areas there is growing is a Professor at U. British WaterWorks is a publication of the Columbia and an Eminent UF/IFAS Department of Fisheries and Scholar in the UF/IFAS Aquatic Sciences, aimed at providing Department of Fisheries and Aquatic Sciences. up-to-date information on activities of the Department to prospective students, alumni, stakeholders, and New Students! agency & academic partners. Welcome to Christian Barrientos If you would like to contribute an (PhD student), article or informational bullet for a Jessica Beasley (PhD), future issue of WaterWorks, please Felipe Carvalho (MS), Eric contact the Editor, Dr. Karl Havens, Casiano (MS), Amanda An enrollment of 28 professionals from 13 countries by email at [email protected] or by Foss (MS), John Hargrove joined 8 organizers and lecturers including FAS’ (MS), Nathan Johnson own Bill Seaman (far left, third row up) for the telephone at 352-392-9617 x 232. (PhD) , Darren Pecora week-long short course in Zaragoza Spain. (MS), Eric Thomas (MS), Thank you. and Erika Thompson (MS).

2 3 Florida Ecosystems in the Spotlight The Kissimmee Chain of Lakes

The Kissimmee Chain is a group of natural lakes located just to the south of Orlando, forming the headwaters of the Kissimmee River and the northernmost part of the greater Everglades ecosystem. The numerous lakes of the Kissimmee Chain were historically connected by streams and sloughs and it was typical for the lakes to experience large seasonal and year-to-year variations in water level. This unpredictable hydrology resulted in diverse communities of submerged and emergent aquatic plants and adjacent wetlands around the lakes, which provided a large regional habitat for fish, wading birds and migratory waterfowl. Today the lakes continue to support important ecological values and several of them are prized for their recreational fisheries -- in particular largemouth bass. However, the natural hydrologic variability has largely been lost in most of the lakes, as a result of man-made canals that now connect many of the lakes and regulate water levels -- necessary because development has occurred in many places right down to the region of historic high water. In recent decades, stabilized water levels in the Kissimmee Chain, coupled with explosive growth of the invasive plant Hydrilla, have led to reduced diversity of shoreline plant communties and build up of ‘tussocks’ of dead plant material and detrital muck along the lake shore. This material degrades the shoreline habitat and reduces the lake’s ecological and societal values. To address the problem, state and federal agencies have traditionally carried out short-term rehabilitation projects in which water levels are lowered, muck is scraped from the shoreline and deposited in spoil islands within the lake, and herbicides are used to control regrowth of undesirable plants. The South Florida Water Management District and its state and federal partners now are looking at ways to reintroduce more of the natural hydrologic variation to these lakes, as a longer-term solution to the problems noted above. UF Faculty, including Dr. Mike Allen, serve on advisory panels for this work. [Photo Credit: www.sfwmd.gov]

that healthy lobsters are able to detect and avoid Rock Lobster! diseased lobsters, potentially limiting disease Don Behringer is our newest FAS faculty member. His transmission in the wild. This is the first discovery of research focuses on near-shore marine environments such a behavior and it stands to change our perceptions where he studies the impact of human-related changes regarding the role of behavior in the transmission of in habitat and water quality on organisms at population disease in social animals. and community levels. His current research deals with the dynamics of a lethal pathogen that infects the In addition to this work with spiny lobsters, Dr. Carribean spiny lobster. Behringer has worked on the inter-habitat connectance of food webs using stable isotope tracer techniques. This research is centered on PaV1, an irido-like virus In the Carribean, seagrasses produce much of the that he and colleagues at Old Dominion University and organic carbon in shallow waters, and it has long the Virginia Institute of Marine Sciences discovered in been assumed that much of this carbon is exported to 1999. It is the first naturally-occurring virus found in nearby habitats, supporting their foodwebs. However any lobster. recent results with hard bottom habitats suggest they are largely supported by autochothonous production The goal of this of algae rather than seagrass. research program is to detemine how Dr. Behringer also is interested in the influence of stressful environmental enhancement, restoration, and conservation efforts conditions, coupled on populations and communities. The use of artificial with life history changes enhancement mechanisms to maximize animal in host behavior and abundances is widespread and while most investigators disease susceptibility, have studied the efficacy of the mechanism, the effect generate the pattern of of habitat enhancement on the processes creating infection prevalence such patterns remains largely unknown. and distribution observed in the Florida Contact the author: Keys. One important [email protected] early result is a finding 4