The distribution of seagrasses in Dominica, Lesser Antilles

Seagrass beds are the largest organism-built marine habitat in Dominica, yet have only been surveyed since 2007. Standardized examinations along a depth gradient between 0 and 24 m, focusing on magnoliophyte species composition and benthic cover of shoots at 17 seagrass bed sites, were carried out between September 10 and December 7, 2008. The Cymodoceaceae Syringodium filiforme (Kuetzing 1860) and Halodule wrightii (Ascherson 1868), as well as the Hydrocharitaceae Halophila decipiens (Ostenfeld 1902), H. stipulacea (Fosskal & Ascherson 1867) and Thalassia testudinum (Banks ex K?nig 1805) displayed distinct regional and horizontal distribution patterns. Syringodium filiforme is the island's dominant seagrass along the western and northern coasts, occurring at depths between 2 and 18 m and with a mean benthic cover ranging from 0.9-10% along the West coast. Along the North coast it grew between 0.2 and 1 m depth with a mean maximum benthic cover of 48.9%. Halodule wrightii grew along the North and West coasts, in depths between 1 and 14m in areas of recent and chronic disturbances. Its delicate morphology and sparse benthic cover (< 0.1%) did not constitute seagrass beds. Halophila decipiens grew along the deep, shallow and lateral margins of west coast S. filiforme beds and monospecifically in depths between 3 and 24m. Halophila stipulacea, an invasive species, was widespread along 45km of the West coast and was found in depths between 5 and 24m. Both Halophila species formed extensive beds at depths beyond the survey limit of 24m thus playing a potentially important role in the resettlement of shallow areas after storms. H. decipiens and H. stipulacea are currently the second and third most common seagrasses on the island respectively, despite their absence along the North coast. T. testudinum was confined to North coast's sheltered reef flats at depths Im or less with mean a benthic cover ranging from 2 to 76%. It grew monospecifically in the most turbulent and in the calmest locations, yet intermixed with S. filiforme in areas of moderate turbulence. Strong surge along the West coast (October 15-16, 2008), associated with Hurricane Omar, caused uprooting and burial of seagrass beds in varying degrees, in particular along the shallow margins between 2 and 10m depth. This event also demonstrated the dynamic nature of Dominica's shallow seagrass bed margins and the resistance level of individual beds to storm disturbances.     

三种类型互花米草抗盐生态型的分化

从美国引种成功的三种类型互花米草在不同NaCl浓度的盐渍生境中,叶细胞膜透性、渗透调节物(主要是K+、Na+)和氨基酸的变化以及光合作用、呼吸作用的变化都存在明显的差异,这是由于长期不同生境的选择和互花米草的基因型适应所造成的生态型分化的结果。按抗盐性分：G型抗性最强、F型最弱、N型居中。     

Survival and Expansion of Mechanically Transplanted Seagrass Sods

Although planting seagrass is not technically complex, the ability to plant large areas is limited by the time-consuming nature of manual methods. Additionally, manual methods use small, spatially isolated planting units (PUs; shoot bundles or plugs/cores) that are often highly susceptible to disturbance. The likelihood for harvesting intact apical meristems may be higher with large sods compared to smaller units, thus increasing survival and expansion rates. Here, we examined the survival and expansion of large units (1.5 × 1.2 m) of seagrass transplanted using a mechanized planting boat (Giga Unit Transplant System; GUTS). Twenty-seven units of seagrass (18 Halodule wrightii and 9 Thalassia testudinum ) were transplanted and monitored for survival, shoot density, and expansion. After 3 years, 74.1% of the units had survived (66.7% H. wrightii and 88.9% T. testudinum ) with 12 H. wrightii units having expanded substantially beyond the bounds of the original PU, merging with adjacent units to form spatially continuous patches of seagrass. High survival rates for T. testudinum should be interpreted in light of concomitant declines in density and lack of significant expansion after 3 years. In its tested configuration, the GUTS was a viable method for transplanting H. wrightii where donor and receiver sites were in close proximity (<2 km; a current limitation of the GUTS design used here). However, based on the reduced density and lack of significant expansion of T. testudinum that has persisted 3 years post-transplant, the GUTS cannot yet be fully recommended for transplanting this species.     

Evaluation of Seagrass Planting and Monitoring Techniques: Implications for Assessing Restoration Success and Habitat Equivalency

Restoration has become an integral part of coastal management as a result of seagrass habitat loss. We studied restoration of the seagrass (Halodule wrightii) near Tampa Bay, Florida. Experimental plots were established in June 2002 using four planting methods: three manually planted and one mechanically transplanted by boat. Seagrass cover was recorded at high resolution (meter scale) annually through July 2005. Natural seagrass beds were concurrently examined as reference sites. We also evaluated the suitability of a commonly used protocol (Braun‐Blanquet scores, BB) for comparing the development of seagrass cover using the planting methods and quantifying spatial patterns of cover over time. Results show that BB scores mirrored conventional measures of seagrass characteristics (i.e., shoot counts and above‐ and belowground biomass) well when BB scores were either low or very high. However, more caution may be required at intermediate cover scores as judged by comparison of BB scores with direct measurement of seagrass abundance. Significant differences in seagrass cover were detected among planting methods and over time (2002–2005), with manual planting of rubber band units resulting in the highest cover. In contrast, the peat pot and mechanical planting methods developed very low cover. Recovery rates calculated from development of seagrass spatial cover were less than those reported for natural expansion. Importantly, time to baseline recovery may be substantially greater than 3 years and beyond standard monitoring timelines. Prolonged recovery suggests that the rate of service returns, critical for estimating compensatory restoration goals under habitat equivalency analysis, may be severely underestimated.     

Fine-scale population structure of bottlenose dolphins (Tursiops truncatus) in Tampa Bay, Florida

Some populations of coastal bottlenose dolphins ( Tursiops truncatus ) comprise discrete communities, defined by patterns of social association and long-term site fidelity. We tested the hypothesis that bottlenose dolphins in Tampa Bay, Florida, form a single community. The longitudinal study of dolphins in Sarasota Bay, adjacent to Tampa Bay, allowed us to ground-truth the definition of community and test whether our approach was robust to small sample sizes of resightings. We conducted photo-identification surveys in Tampa Bay during 1988–1993, and identified 102 dolphins with 10 or more sightings. We used hierarchical cluster analysis to examine the locations and association indices of these dolphins. We used analysis of variance (ANOVA) to test for differences in mean locations and determine whether mean coefficient of association (CoA) values within a community were higher than among communities. Dolphins in Tampa Bay clustered into five putative communities differing significantly in location and CoA values. Kernel estimates of the ranges of these five communities exhibited little overlap; some communities had no overlap at all. We conclude that five discrete communities of bottlenose dolphins exist in Tampa Bay and that such fine-scale structure may be a common feature of bottlenose dolphin populations throughout the southeastern United States.     

Geographic variation in reproduction between two populations of the bonnethead shark,Sphyrna tiburo

Synopsis A study of two populations of the bonnethead shark,Sphyrna tiburo was conducted in Florida Bay and Tampa Bay, Florida from September 1982 to December 1986. The maintenance of sharks in captivity at the Marine Science and Conservation Center in the Florida Keys, and the collection of sharks from widely separated geographical areas allowed the examination of latitudinal variation in reproduction. Several reproductive parameters were found to differ: (1) size at maturation, (2) age at maturation, (3) time of fertilization, (4) rate of embryonic development, (5) size at birth, (6) the energetic investment in producing offspring, (7) gestation period, and (8) the incidence of infertility. Average litter size and maximum age of females was not different between the two populations. These contrasting life history parameters are not easily explained. Food limitation and seasonal differences between the two areas are considered as factors controlling reproduction in these populations. It is noteworthy that the average size of adult females in Tampa Bay is significantly greater than that of Florida Keys sharks. This size difference may be important in explaining the observed differences in reproduction.     

Patterns of larval release in the Florida stone crab, Menippe mercenaria

Larval release patterns in brachyuran crabs are often synchronized with environmental cycles. While previous studies have focused extensively on supratidal and intertidal taxa, there have been relatively few investigations of subtidal species. This study examined patterns of larval release by the Florida stone crab, Menippe mercenaria, from three different tidal regimes. Ovigerous stone crabs were collected from Sebastian Inlet on the east coast of Florida, Tampa Bay on the west coast of Florida, and the Florida Keys. Patterns of larval release were monitored in the laboratory in relation to local tidal and diel cycles. Results showed a significant diel pattern in initiation of hatching by crabs from each of three study areas. Larval release consistently occurred during the diurnal phase despite the maintenance of females in constant laboratory conditions for up to 96 h prior to hatching. This implies that release may be controlled by a circadian clock. Patterns of release by stone crabs in relation to tidal cycle were more variable. Larval release by females from populations near Tampa Bay and Sebastian Inlet were not synchronized with the tides, whereas females collected from the Florida Keys exhibited a pattern that was strongly related to tidal cycle. These results may be explained by differences in tidal amplitude at the three sampling locations.     

PILINIA EARLEAE N. SP. (CHLOROPHYCEAE,CHROOLEPIDACEAE) FROM THE FLORIDA WEST COAST1

Pilinia earleae n. sp. family Chroolepidaceae, was found in the Tampa Bay area of the Florida west coast in October, 1976, on the tunic of an ascidian, later on dead mollusc shells, a nylon faking line, plastic strips, and as an epiphyte of Gracilaria foliifera, a red alga. It is described on the basis of abundant material from the natural environment and laboratory cultures. The type locality is the southernmost known for the genus in the western North Atlantic.     

A comparison of the Nzi,Horse Pal® and Bite‐Lite® H‐traps and selected baits for the collection of adult Tabanidae in Florida and North Carolina

Despite the veterinary and medical importance of horse flies, deer flies, and yellow flies, only a few trap types have been evaluated to monitor adult population dynamics. Currently, three trap types are being utilized (H‐trap, Horse Pal® (HP), and Nzi trap), but no head‐to‐head comparisons have been reported. Thus, we conducted comparative trapping studies in Florida and North Carolina. At two study sites in Florida, the efficacy of all three trap types was compared, but only the H‐trap and HP were compared in North Carolina. Although trap type was significant at all sites, the trap type which caught the most specimens was not the same. In Florida at the Lower Suwannee Wildlife Refuge (LSWR) site, the H‐trap caught the most specimens (2,006), followed in decreasing order by Nzi (938) and HP (541). At the Cedar Ridge Ranch site, the Nzi caught significantly more specimens (1,439) than the H‐trap (215) and HP (161), which were not significantly different from each other. In North Carolina, the H‐trap caught approximately twice as many specimens as the HP (1,458 vs 720). These trap comparison studies were followed up by a study on the efficacy of various bait combinations: (No Bait (NB), dry ice only (DI), Trap Tech Lure (TTL) only, and DI + TTL), which was conducted only at the two Florida sites with H‐traps. At both sites, bait combinations significantly affected trap collections. One pattern (DI +TTL > DI > TTL > NB) was recorded at the LSWR, while at the Cedar River Ranch the pattern was DI > DI +TTL > TTL > NB. Our data showed that trap type and bait combination significantly influence overall adult tabanid abundance as well as individual species composition.     

Functional and metabolic characterization of hemocytes of the green mussel, Perna viridis: in vitro impacts of temperature

The green mussel, Perna viridis, is a bivalve mollusk native to Asia and was recently introduced to Florida, USA. Since its first observation in 1999 in Tampa Bay, Florida, green mussel population has expanded considerably, to reach the Atlantic coast of Florida, Georgia and South Carolina. Most of currently available studies about the ecology and biology of green mussels were performed in the Indian and Pacific oceans. Very recently, it has been suggested that due to a weak low temperature resistance, green mussels might have already reached the Northern edge of their distribution in the USA. However, there is currently an obvious lack of data about the adaptation capacities of Perna viridis to environmental conditions in Florida, especially at the physiological and cellular levels. In the present work, we determined and characterized the populations of circulating hemocytes, and the cellular components of hemolymph involved in various physiological functions, including immunity. Two main populations were characterized, hyalinocytes and granulocytes. Granulocytes accounted for 60% of circulating cells, and displayed higher phagocytic capacities, lysosomal content and basal oxidative metabolism than hyalinocytes. Hemocyte parameters were not influenced by the size of green mussels. In addition, hemocytes were subjected to acute temperature challenges (10, 20 and 30 °C) and their immune-related functions and metabolism analyzed. Our results showed that 10 °C represent a stressful condition for the Floridian green mussels, as depicted by a low phagocytosis capacity and an increase of oxidative metabolism.     

Phosphorus transformations from rock phosphates in acid soils and measures for increasing their efficiency for growing rice (Oryza sativa L.)

Summary Laboratory incubation experiments showed that addition of rock phosphate to P-deficient acid red and laterite soils resulted in an increase in Al–P or/and Fe–P, with a consequent decrease in Ca–P during 15 days, of moist aerobic incubation. The transformations of P from Gafsa, Jordan, North Carolina and Florida rock phosphates were more than those from Tennessee, Missouri and Udaipur. Studies with North Carolina, Gafsa, and Udaipur rock phosphates showed that application of the former two to moist aerobic P-deficient acid soils 2 weeks prior to flooding and transplanting rice gave higher content of Al–P, Fe–P and Bray-P, compared to when these were applied at flooding. The grain yields obtained with the former two treatments were also at par with that obtained with the addition of superphosphate at comparable rate (100 ppm) of P application, compared to when the, rock phosphates were applied at flooding, where the grain yields were lower than the superphosphate treatment, indicating that some of these rock phosphates could be made as efficient as superphosphate for growing rice on acid soils by their application to moist aerobic soil, 2–3 weeks prior to flooding and transplanting rice and thus conserve some amount of sulphur required for the manufacture of water soluble phosphates.     

Prevalence of 2009 pandemic influenza A (H1N1) virus antibodies, Tampa Bay Florida--November-December, 2009

Background

In 2009, a novel influenza virus (2009 pandemic influenza A (H1N1) virus (pH1N1)) caused significant disease in the United States. Most states, including Florida, experienced a large fall wave of disease from September through November, after which disease activity decreased substantially. We determined the prevalence of antibodies due to the pH1N1 virus in Florida after influenza activity had peaked and estimated the proportion of the population infected with pH1N1 virus during the pandemic.

Methods

During November-December 2009, we collected leftover serum from a blood bank, a pediatric children''s hospital and a pediatric outpatient clinic in Tampa Bay Florida. Serum was tested for pH1N1 virus antibodies using the hemagglutination-inhibition (HI) assay. HI titers ≥40 were considered seropositive. We adjusted seroprevalence results to account for previously established HI assay specificity and sensitivity and employed a simple statistical model to estimate the proportion of seropositivity due to pH1N1 virus infection and vaccination.

Results

During the study time period, the overall seroprevalence in Tampa Bay, Florida was 25%, increasing to 30% after adjusting for HI assay sensitivity and specificity. We estimated that 5.9% of the population had vaccine-induced seropositivity while 25% had seropositivity secondary to pH1N1 virus infection. The highest cumulative incidence of pH1N1 virus infection was among children aged 5–17 years (53%) and young adults aged 18–24 years (47%), while adults aged ≥50 years had the lowest cumulative incidence (11–13%) of pH1N1 virus infection.

Conclusions

After the peak of the fall wave of the pandemic, an estimated one quarter of the Tampa Bay population had been infected with the pH1N1 virus. Consistent with epidemiologic trends observed during the pandemic, the highest burdens of disease were among school-aged children and young adults.     

Factors Affecting Restoration of Halodule wrightii to Galveston Bay, Texas

Experimental restoration of Halodule wrightii (shoalgrass) to its former range on Galveston Island, Texas, began in April 1994. We tested the effects of site, planting density, water depth, and fertilizer addition on survival and growth through June 1996. Temperature, salinity, light transmittance, turbidity, and sediment properties at two restoration sites, Redfish Cove and Snake Island Cove, were similar to those in naturally occurring grassbeds in nearby Christmas Bay. Halodule survival, coverage, and new shoot densities were affected by site (significantly higher at Redfish Cove than at Snake Island Cove, which eventually failed), by planting density (significantly higher when planted on 0.25-m or 0.5-m centers rather than on 1.0-m centers), and by water depth (significantly higher when planted in relatively shallow water). Propagation (spreading from transplant units) was significantly greater from 0.25-m or 0.5-m center plantings but was not consistently affected by site or water depth. Fertilizer enhanced propagation but not survival. After two years, Redfish Cove produced belowground biomass similar to that observed in Christmas Bay, but aboveground biomass remained significantly less. Snake Island Cove plant mortality in September 1995 may have been presaged by low root-rhizome carbohydrate levels observed in October 1994, but causes remain unknown. Further restoration of Halodule to Galveston Bay is possible at selected sites, but structural equivalency will take longer than two growing seasons to achieve.     

The Value of Long‐Term Assessment of Restoration: Support from a Seagrass Investigation

The importance of judging success of restoration studies over extended time periods has been repeatedly voiced but convincing information to justify increased monitoring is generally unavailable. Building on Bell et al. (2008), we investigated the development of areal coverage of the seagrass, Halodule wrightii, as a metric for assessing the outcome of a restoration effort conducted near Tampa Bay, Florida, U.S.A., over 7 years, thereby expanding the timescale over which a subtropical seagrass restoration project was evaluated for success. In each of 12 plots, 500 planting units of H. wrightii were introduced in 2002, and the seagrass cover level documented annually through 2009. Although only low‐moderate levels of H. wrightii cover were recorded after 3 years, a rapid increase to high coverage levels was evident in many plots after 2006 and sustained through 2009. Plots that supported only low levels of seagrass cover initially remained poor performers, 4–7 years post‐planting. By 2008, substantial seagrass spillover, contiguous with over 75% of plots, was recorded. When both within‐plot coverage and spillover were considered, seagrass restoration success was attained 6 years after initiation. Our findings provide an example of comparatively longer‐term monitoring of a restoration effort leading to reversal of an earlier evaluation of project success. Moreover, unique information on H. wrightii temporal dynamics emerged from the 7 year study, further illustrating the value of long‐term assessment of restoration. Extending the duration of post‐planting surveys of seagrass coverage may address multiple needs as it advances the field of seagrass restoration .     

Effect of Planting Date on Population Densities of Hoplolaimus columbus and Yield of Soybean

During the 1991 and 1992 soybean growing seasons, field plots were established in South Carolina to study the effect of planting date on at-planting nematode densities and subsequent yield losses caused by Hoplolaimus columbus. The susceptible and intolerant soybean cv. Braxton was planted on five dates from to May to 28 June in 1991 and from 12 May to 28 June in 1992. Nematodes were recovered from soil samples collected before nematicide treatment with 1,3-D (Pi), at 6 weeks after planting (Pm), and at harvest (Pf). Initial nematode population densities did not differ among the five dates of planting in either year. The increase in numbers of nematodes from planting to 6 weeks after planting (Pm/Pi) and from planting to harvest (Pf/Pi) were not different among the five planting dates in either year. Root samples also were collected at 6 weeks after planting and at harvest, but planting date did not affect the number of nematodes extracted from roots on any sample date in either year. Altering planting dates between early May and late June was not effective in preventing yield suppression due to H. columbus.     

Toxoplasmosis in Atlantic bottle-nosed dolphins (Tursiops truncatus)

A female Atlantic bottle-nosed dolphin (Tursiops truncatus) and her calf were found beached on Picnic Island in Tampa Bay, Florida, USA. Despite therapy the animals died. Necropsy revealed severe pneumonia and lymphadenopathy in the mother and the calf, gastric ulcers and infection with the stomach digenean Braunina cordiformis in the mother, and a large, pale liver in the calf. Toxoplasma gondii was identified by light and electron microscopy and by immunohistochemistry in tissues of both animals. Toxoplasma gondii was associated with interstitial pneumonia, necrotizing adrenalitis, and cardiac myonecrosis in the mother and with lymphoid necrosis in both dolphins. The source of infection and the relationship to the recent dolphin beachings along the eastern seacoast of North America are unknown. This is the first report of toxoplasmosis in cetaceans.     

Influence of salinity and temperature on the germination of Ruppia maritima L. from the North Atlantic and Gulf of Mexico

Seeds from the seagrass Ruppia maritima L. collected in North Carolina and Florida were tested for their germination at 17, 23 and 29°C and at 0, 15 and 30%. salinities. Percent germination was significantly higher for seeds from North Carolina and the seeds from Florida did not germinate in 30%. salinity. The northern population also had a more rapid rate of germination. These germination patterns suggest that ecotypic differentiation in germination occurred between the two populations in relation to salinity but not temperature.     

The salinity tolerance of Ophiothrix angulata (Say) (Echinodermata: Ophiuroidea) in latitudinally separate populations

Ophiothrix angulata (Say) from an estuary in South Carolina were less tolerant of reduced salinity than those from an estuary in Florida. Animals from North Inlet, South Carolina, became incapacitated more rapidly after exposure to a reduced salinity, and were less able to recover after return to normal salinity. This difference probably results from the more severe selection for salinity tolerance at Cedar Key, Florida. The Florida estuary has a lower average salinity (25‰) than that in South Carolina (30‰), and has more frequent extended periods of reduced salinity. The two populations are of different color varieties and size; there may be differences in the breeding seasons as well. The South Carolina and Florida populations of Ophiothrix angulata may represent different races.     

Evidence of susceptibility to morbillivirus infection in cetaceans from the United States

Cetacean morbilliviruses (CeMV) are viruses that can cause mass mortalities among various odontocete species. In this study levels of “herd” immunity in cetaceans from the U.S. coast are described from the distribution and prevalence of antibodies against morbilliviruses. Neutralizing antibody titers against dolphin morbillivirus (DMV), porpoise morbillivirus (PMV), phocine distemper (PDV), and canine distemper viruses (CDV) were measured. Positive samples had higher titers against the CeMV than against the other morbilliviruses tested, indicating that although PDV or CDV can be used to investigate exposure their use may result in a higher false negative rate. The results suggest that morbillivirus did not persist in coastal populations of bottlenose dolphins (Tursiops truncatus) after the major outbreaks that occurred in the 1980s and 1990s. Bottlenose dolphins from Beaufort, North Carolina; St. Joseph Bay, Florida; and Cape May, New Jersey had anti‐DMV seroprevalences ranging from between 15% and 33% but those from Charleston, South Carolina and Sarasota Bay, Florida, sampled in recent years were largely negative. These latter groups are therefore now vulnerable to infection and could experience high mortality if exposed to CeMV. Sero‐surveys of this kind are therefore vital for assessing the risk of new and recurring viral outbreaks in coastal cetaceans.     

Efficiency of blue mussel (Mytilus edulis) spat collectors in highly dynamic tidal environments of the Lower Saxonian coast (southern North Sea)

Traditional mussel culture in the Wadden Sea, southern North Sea, is carried out by taking seed mussels of about 1-4 cm shell length from natural beds and transplanting them to permanently water covered sites. Besides the damage done to the natural beds, the ratio of seeded to harvested mussels is only about 1:1-1.3, i.e. about the same tonnage of mussels seeded is recovered. In addition, this technique relies exclusively on natural spat falls, which do not occur regularly. In order to overcome these difficulties spat collectors have been deployed in the Jade Bay, southern North Sea. These provided suitable settlement grounds for mussel larvae. Blue mussel weights reached weights of about 8-9 kg/m collector rope with maximum shell lengths of 4-5 cm within one growing season.