Ecological condition of coastal ocean waters of the U.S. continental shelf off South Florida: 2007

A study was initiated with field work in May 2007 to assess the status of ecological condition and stressor impacts throughout the U.S. continental shelf off South Florida, focusing on soft-bottom habitats, and to provide this information as a baseline for evaluating future changes due to natural or human-induced disturbances. The boundaries of the study region extended from Anclote Key on the western coast of Florida to West Palm Beach on the eastern coast of Florida, inclusive of the Florida Keys National Marine Sanctuary (FKNMS), and from navigable depths along the shoreline seaward to the shelf break (~100m). The study incorporated standard methods and indicators applied in previous national coastal monitoring programs — U.S. Environmental Protection Agency’s (EPA) Environmental Monitoring and Assessment Program (EMAP) and National Coastal Assessment (NCA) — including multiple measures of water quality, sediment quality, and biological condition. Synoptic sampling of the various indicators provided an integrative weight-of-evidence approach to assessing condition at each station and a basis for examining potential associations between presence of stressors and biological responses. A probabilistic sampling design, which included 50 stations distributed randomly throughout the region, was used to provide a basis for estimating the spatial extent of condition relative to the various measured indicators and corresponding assessment endpoints (where available). The study was conducted through a large cooperative effort by National Oceanic and Atmospheric Administration (NOAA)/National Centers for Coastal Ocean Science (NCCOS), EPA, U.S. Geological Survey (USGS), NOAA/Oceanic and Atmospheric Research (OAR)/Atlantic Oceanographic and Meteorological Laboratory in Miami, FKNMS, and the Florida Fish and Wildlife Conservation Commission (FWC). The majority of the South Florida shelf had high levels of dissolved oxygen (DO) in near-bottom water (> 5 mg L-1) indicative of “good” water quality.. DO levels in bottom waters exceeded this upper threshold at 98.8% throughout the coastal-ocean survey area. Only 1.2% of the region had moderate DO levels (2-5 mg/L) and no part of the survey area had DO <2.0 mg/L. In addition, offshore waters throughout the region had relatively low levels of total suspended solids (TSS), nutrients, and chlorophyll a indicative of oligotrophic conditions. Results suggested good sediment quality as well. Sediments throughout the region, which ranged from sands to intermediate muddy sands, had low levels of total organic carbon (TOC) below bioeffect guidelines for benthic organisms. Chemical contaminants in sediments were also mostly at low, background levels. For example, none of the stations had chemicals in excess of corresponding Effects-Range Median (ERM) probable bioeffect values or more than one chemical in excess of lower-threshold Effects-Range Low (ERL) values. Cadmium was the only chemical that occurred at moderate concentrations between corresponding ERL and ERM values. Sixty fish samples from 28 stations were collected and analyzed for chemical contaminants. Eleven of these samples (39% of sites) had moderate levels of contaminants, between lower and upper non-cancer human-health thresholds, and ten (36% of sites) had high levels of contaminants above the upper threshold.

Accelerating loss of seagrasses across the globe threatens coastal ecosystems

Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling; an order of magnitude enhancement of coral reef fish productivity; a habitat for thousands of fish, bird, and invertebrate species; and a major food source for endangered dugong, manatee, and green turtle. Although individual impacts from coastal development, degraded water quality, and climate change have been documented, there has been no quantitative global assessment of seagrass loss until now. Our comprehensive global assessment of 215 studies found that seagrasses have been disappearing at a rate of 110 square kilometers per year since 1980 and that 29% of the known areal extent has disappeared since seagrass areas were initially recorded in 1879. Furthermore, rates of decline have accelerated from a median of 0.9% per year before 1940 to 7% per year since 1990. Seagrass loss rates are comparable to those reported for mangroves, coral reefs, and tropical rainforests and place seagrass meadows among the most threatened ecosystems on earth.

Use of skeletochronological analysis to estimate the age of leatherback sea turtles Dermochelys coriacea in the western North Atlantic

Although growth rate and age data are essential for leatherback management, estimates of these demographic parameters remain speculative due to the cryptic life history of this endangered species. Skeletochronological analysis of scleral ossicles obtained from 8 captive, known-age and 33 wild leatherbacks originating from the western North Atlantic was conducted to characterize the ossicles and the growth marks within them. Ages were accurately estimated for the known-age turtles, and their growth mark attributes were used to calibrate growth mark counts for the ossicles from wild specimens. Due to growth mark compaction and resorption, the number of marks visible at ossicle section tips was consistently and significantly greater than the number visible along the lateral edges, demonstrating that growth mark counts should be performed at the tips so that age is not underestimated. A correction factor protocol that incorporated the trajectory of early growth increments was used to estimate the number of missing marks in those ossicles exhibiting resorption, which was then added to the number of observed marks to obtain an age estimate for each turtle. A generalized smoothing spline model, von Bertalanffy growth curve, and size-at-age function were used to obtain estimates of age at maturity for leatherbacks in the western North Atlantic. Results of these analyses suggest that median age at maturation for leatherbacks in this part of the world may range from 24.5 to 29 yr. These age estimates are much greater than those proposed in previous studies and have significant implications for population management and recovery.

Life history and population dynamics of the finetooth shark (Carcharhinus isodon) in the northeastern Gulf of Mexico

The life history and population dynamics of the finetooth shark (Carcharhinus isodon) in the north-eastern Gulf of Mexico were studied by determining age, growth, size-at-maturity, natural mortality, productivity, and elasticity of vital rates of the population. The von Bertalanffy growth model was estimated as Lt=1559 mm TL (1–e–0.24 (t+2.07)) for females and Lt = 1337 mm TL (1–e–0.41 (t+1.39)) for males. For comparison, the Fabens growth equation was also fitted separately to observed size-at-age data, and the fits to the data were found to be similar. The oldest aged specimens were 8.0 and 8.1 yr, and theoretical longevity estimates were 14.4 and 8.5 yr for females and males, respectively. Median length at maturity was 1187 and 1230 mm TL, equivalent to 3.9 and 4.3 yr for males and females, respectively. Two scenarios, based on the results of the two equations used to describe growth, were considered for population modeling and the results were similar. Annual rates of survivorship estimated through five methods ranged from 0.850/yr to 0.607/yr for scenario 1 and from 0.840/yr to 0.590/yr for scenario 2. Productivities were 0.041/yr for scenario 1 and 0.038/yr for scenario 2 when the population level that produces maximum sustain-able yield is assumed to occur at an instantaneous total mortality rate (Z) equaling 1.5 M, and were 0.071/yr and 0.067/yr, when Z=2 M for scenario 1 and 2, respectively. Mean generation time was 6.96 yr and 6.34 yr for scenarios 1 and 2, respectively. Elasticities calculated through simulation of Leslie matrices averaged 12.6% (12.1% for scenario 2) for fertility, 47.7% (46.2% for scenario 2) for juvenile survival, and 39.7% (41.6% for scenario 2) for adult survival. In all, the finetooth shark exhibits life-history and population characteristics intermediate to those of sharks in the small coastal complex and those from some large coastal species, such as the blacktip shark (Carcharhinus limbatus).

Age and growth of the estuarine dolphin (Sotalia guianensis) (Cetacea, Delphinidae) on the Paraná Coast, southern Brazil

Teeth of 71 estuarine dolphins (Sotalia guianensis) incidentally caught on the coast of Paraná State, southern Brazil, were used to estimate age. The oldest male and female dolphins were 29 and 30 years, respectively. The mean distance from the neonatal line to the end of the first growth layer group (GLG) was 622.4 ±19.1 μm (n=48). One or two accessory layers were observed between the neonatal line and the end of the first GLG. One of the accessory layers, which was not always present, was located at a mean of 248.9 ±32.6 μm (n=25) from the neonatal line, and its interpretation remains uncertain.The other layer, located at a mean of 419.6 ±44.6 μm (n=54) from the neonatal line, was always present and was first observed between 6.7 and 10.3 months of age. This accessory layer could be a record of weaning in this dolphin. Although no differences in age estimates were observed between teeth sectioned in the anterior-posterior and buccal-lingual planes, we recommend sectioning the teeth in the buccal-lingual plane in order to obtain on-center sections more easily. We also recommend not using teeth from the most anterior part of the mandibles for age estimation. The number of GLGs counted in those teeth was 50% less than the number of GLGs counted in the teeth from the median part of the mandible of the same animal. Although no significant difference (P>0.05) was found between the total lengths of adult male and female estuarine dolphins, we observed that males exhibited a second growth spurt around five years of age. This growth spurt would require that separate growth curves be calculated for the sexes. The asymptotic length (TL∞), k, and t0 obtained by the von Bertalanffy growth model were 177.3 cm, 0.66, and –1.23, respectively, for females and 159.6 cm, 2.02, and –0.38, respectively, for males up to five years, and 186.4 cm, 0.53 and –1.40, respectively, for males older than five years. The total weight (TW)/total length (TL) equations obtained for male and female estuarine dolphins were TW = 3.156 × 10−6 × TL 3.2836 (r=0.96), and TW = 8.974 × 10−5 × TL 2.6182 (r=0.95), respectively.

Reproduction in the protogynous black grouper Mexico (Mycteroperca bonaci (Poey)) from the southern Gulf of Mexico

An analysis was made of sexual pattern, spawning season, sizes at sexual maturation, and sex change in black grouper (Mycteroperca bonaci) from the southern Gulf of Mexico. Samples were taken between 1996 and 2000, from industrial and small-craft commercial fi sheries, in offshore and inshore waters of the continental shelf of the Yucatan Peninsula (Campeche Bank), including the shallow waters of National Marine Park Alacranes Reef. For all collected specimens (n=1229), sex and maturation condition were determined by histological analysis of the gonads. The offshore sample consisted of 75.1% females, 24.3% males, and 0.6% transitional-stage fish. All individuals collected from inshore waters were females. Gonadal structure and population structure characteristics for Campeche Bank black grouper were consistent with the characteristics of monandric protogynous hermaphrodism for a serranid fish. Sexually active males and females were observed year-round, although ripening females, with stage-III, -IV, and -V vitellogenic oocytes in the ovaries, dominated in samples taken between December and March. In addition, peak occurrence of ripe-running females with hyaline oocytes or postovulatory follicles (or both) in the ovaries was recorded in January and February. A few precocious females began spawning in October and November, and others were still in spawning condition in May and June. Fifty percent maturity of females was attained at 72.1 cm fork length (FL). Median size at sexual inversion was 103.3 cm FL, and 50% of the females measuring 111.4 cm FL had transformed into males. The southern Gulf of Mexico grouper fishery was considered deteriorated and lacked a well-defined management strategy. Results of the present study provide helpful information on black grouper reproduction in this area and could help Mexican authorities choose appropriate management strategies for this fishery, such as minimum size limit, closed fishing season, and protection of spawning aggregations.

Stock-rebuilding time isopleths and constant-F stock-rebuilding plans for overfished stocks

Stock-rebuilding time isopleths relate constant levels of fishing mortality (F), stock biomass, and management goals to rebuilding times for overfished stocks. We used simulation models with uncertainty about FMSY and variability in annual intrinsic growth rates (ry) to calculate rebuilding time isopleths for Georges Bank yellowtail flounder, Limanda ferruginea, and cowcod rockfish, Sebastes levis, in the Southern California Bight. Stock-rebuilding time distributions from stochastic models were variable and right-skewed, indicating that rebuilding may take less or substantially more time than expected. The probability of long rebuilding times increased with lower biomass, higher F, uncertainty about FMSY, and autocorrelation in ry values. Uncertainty about FMSY had the greatest effect on rebuilding times. Median recovery times from simulations were insensitive to model assumptions about uncertainty and variability, suggesting that median recovery times should be considered in rebuilding plans. Isopleths calculated in previous studies by deterministic models approximate median, rather than mean, rebuilding times. Stochastic models allow managers to specify and evaluate the risk (measured as a probability) of not achieving a rebuilding goal according to schedule. Rebuilding time isopleths can be used for stocks with a range of life histories and can be based on any type of population dynamics model. They are directly applicable with constant F rebuilding plans but are also useful in other cases. We used new algorithms for simulating autocorrelated process errors from a gamma distribution and evaluated sensitivity to statistical distributions assumed for ry. Uncertainty about current biomass and fishing mortality rates can be considered with rebuilding time isopleths in evaluating and designing constant-F rebuilding plans.

Developmental characters of Psettina Iijimae (Jordan and Starks), bothid flat fishes - Pisces

Post larval stages of Psettina Iijimae ranging from 1.8 mm NL to 44.6 mm SL collected during Naga Expedition and International Indian Ocean Expedition (IIOE) are described. The characteristics which help to identify larval stages of Psettina are: the presence of pigmented urohyal appendage in early stages which is progressively reduced during flexion stages and which disappears in later postflexion stages, the meristics, the spines on urohyal and posterior basipterygial processes and the absence of spines on cleithra. The P. iijimae can be distinguished by the presence of spines on the median fin rays which differentiate near the baseosts along the dorsal and ventral body wall much before the fin rays. The larvae of P.iijimae were more abundant in the Gulf of Thailand compared to South China Sea and Indian Ocean.

Toxicity of heavy metals to brine shrimp Artemia

Bioassay were carried out on 48h cultured nauplii of brine shrimp Artemia by exposing them to seven trace elements viz. copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), lead (Pb), iron (Fe) and manganese (Mn). Synergistic effects of all these elements and additive effects of Cu and Zn, Cd and Pb, and Ni and Fe were also investigated. Comparatively, the degree of toxicity for compound bioassays was higher than individual simple tests. The values were averaged and the expected median lethal concentration [LC sub(50)] of tested heavy metals was obtained by probit analysis on the basis of cumulative numbers of dead organisms after 24 and 48h. The order of toxicity of the metals to Artemia was Pb>Cd>Cu>Ni>Zn>Fe>Mn. Potency ratios of the seven metals were also calculated. The 24 and 48h variations obtained in LC sub(50) values were significantly different and relative implications of these are discussed.

Acute toxicity of chlorpyrifos, cadusafos and diazinon to three Indian major carps (Catla catla, Labeo rohita and Cirrhinus mrigala) fingerlings

Fingerlings of three Indian major carps, viz. Catla catla (Hamilton-Buchanon), Labeo rohita (Hamilton-Buchanon) and Cirrhinus mrigala (Hamilton-Buchanon), were exposed to different concentrations of chlorpyrifos (lorsban 10 G), cadusafos (rugby 10 G) and diazinon (basudin 10 G) for a period of 96h with a view to determine the median lethal concentrations (LC sub50) values for each of chemicals. Of the tested concentrations, chlorpyrifos at a dose of 6.65 ppm, cadusafos at 2.0 ppm and diazinon at a dose of 8.40 ppm or above induced 100% mortalities within 96h of exposure. The 96h LC sub50 values of chlorpyrefos, cadusafos and diazinon were 1.66, 0.72 and 2.10 ppm for C. catla, 2.35, 0.72 and 2.97 for L. rohita and 2.35, 0.72 and 2.10 ppm for C. mrigala, respectively. Pesticide induced behavioral abnormalities observed in the present study included erratic movements, rapid operculum activities, jumping of fish out of the test media, violent spasm and convulsion.

Acute toxicity of four heavy metals to Sphaeroma walkeri and Ciroiana bovina (Crustacea:Isopoda)

The median lethal concentrations (LC50) of two Isopoda species exposed to each tested metal (Cu. Co, Cd and Zn) in static tests for different exposure periods are quite variable depending on the tested metal The LC50 values for Sphaeroma walkeri after 24 hours exposure to Cu and Co were estimated graphically to be 11.20 and 7.00 mg/1 respectively. The correspoding values for Cirolana bovina exposed to Cu, Co, Cd and Zn were 3.60, 11.0, 3.80 and 4.80 mg/1 respectively. For 2 days the LC50 of S. walkeri exposed to Cd was 5.60 mg/l, but it was 10.10 mg/l for 3 days exposure to Zn. After prolonged exposure the LC50 values decreased proportionally with the exposure duration of the test the percentages of surviving animals demonstrated a progressive decrease with increasing concentratins as a main factor from the analysis of variance (ANOV A). The sensitivity of adult S. walkeri exposed to the four heavy metals for different exposure times ranked: Cd>Co>Zn>Cu. Cirolana bovina appeared to be more sensitive to Cu. Cd and Zn than to Co. Species in order of increasing sensitivity is C. bovina more than S. walker.

Cloning of novel bombesin precursor cDNAs from skin of Bombina maxima

Amphibian skin is a rich resource of bioactive peptides like proline-rich bombesin from frog Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises proline-rich bombesin and a novel peptide, designated as bombestatin, was isolated from a skin cDNA library of B. maxima. The predicted primary structure of the novel peptide is WEVLLNVALIRLELLSCRSSKDQDQKESCGMHSW, in which two cysteines form a disulfide bond. A BLAST search of databases did not detect sequences with significant similarity. Bombestatin possesses dose-dependent contractile activity on rat stomach strips. The differences between cDNAs encoding PR-bombesin plus bombestatin and PR-bombesin alone are due to fragment insertions located in 3'-coding region and 3'-untranslational region, respectively. (c) 2005 Elsevier B.V. All rights reserved.

Heterorhabditidoides chongmingensis gen. nov., sp nov (Rhabditida : Rhabditidae), a novel member of the entomopathogenic nematodes

During a recent soil sample survey in Eastern China, a new entomopathogenic nematode species, collected from the Chongming Islands in the southern-eastern area of Shanghai, was discovered. Morphological characteristics of different developmental stages of the nematode combined with molecular data showed that this nematode is a new genus of Rhabditidae, and described as Heterorhabditidoides chongmingensis gen. nov., sp. nov., for that it shares more morphological characteristics with heterorhabditids than with ste-inernematids. For males, the papillae formula of bursa is 1, 2, 3, 3, with constant papillae number in the terminal group, stoma tubular-shaped and about 1.5 head width; cheilorhabdions cuticularized, esophageal collar present and long, median bulb present. For infective juveniles, EP = 90 (80-105) mu m, ES = 104 (92-120) mu m, tail length = 111 (89-159) mu m, and a = 19.1 (15-21). The percentages of the nucleotides A, T, C and G in the ITS1 regions of the new species are significantly different from those of heterorhabditids and other rhabditids. Molecular phylogenetic trees based on 18S rDNA and the internal transcribed spacer (ITS) sequences data revealed that the new entomopathogenic nematode species forms a monophyletic group, which is a sister group of the clade comprised of some genera of Rhabditidae. (c) 2008 Elsevier Inc. All rights reserved.

Pesticide induced physiological and behavioural changes in an estuarine teleost Therapon jarbua (Forsk)

Static bioassays were conducted with pesticides like PP'-DDT, Dimethoate (Rogor) and Carbaryl (Sevin) to determine the median lethal concentrations (LC sub(50)) on an estuarine teleost Therapon jarbua (Forsk). The respiration rates of fishes exposed to pesticides, as well as those of controls were determined. Respiration abnormalities were noticed in treated fishes. The metabolic rates are generally higher in treated fishes than in the controls. The behaviour of fishes exposed to LC sub(25) (96h) concentrations of pesticides is discussed. Estuarine fishes appear to be more sensitive and susceptible to pesticides than fresh water fishes. The pesticides affect the locomotory and swimming behaviour of fishes. Loss in weight of fishes exposed to LC sub(50) (96 h) concentration of pesticides was also estimated. The present report gives a comprehensive account of the toxic nature of these pesticides to fishes.

Vibration of fluid loaded conical shells.

An analytical model is presented to describe the vibration of a truncated conical shell with fluid loading in the low frequency range. The solution for the dynamic response of the shell is presented in the form of a power series. Fluid loading is taken into account by dividing the shell into narrow strips which are considered to be locally cylindrical. Analytical results are presented for different boundary conditions and have been compared with the computational results from a boundary element model. Limitations of the model to the low frequency range are discussed.