Batch cultures of Fayella panamenis were pulse fed Heterocapsa triquetra at concentrations ranging from 200 to 3,000 cells/ml. The digestion process was followed using both bright field and epifluoresence microscopy for live and fixed ciliates. Ingestion rates, vacuole passage times, and the time required for complete digestion of vacuolar contents were determined during pulse feeding experiments. Findings indicate the following. 1) The digestion rate of Favella panamenis begins to saturate at 2,000-2,500 Heterocapsa/ml. The ingestion rate increases over the range of Heterocapsa/ml studied (200 to 3,000 cells/ml). 2) Each ciliate could fully digest ≤ 3 Heterocapsa simultaneously. If the cell ingested ≥ 4 Heterocapsa at one feeding, the food items were excreted partially digested. Ingestion of ≥ 3 Heterocapsa per ciliate began at an initial food concentration of 2,500 Heterocapsa/ml. The results suggests that the rate of digestive enzyme production may limit the transfer of energy through microbial food webs under food saturating or bloom conditions. This may ultimately decrease growth efficiencies at high feeding rates, which then must be considered in energy and carbon flow calculations.

The Florida manatee (Trichechus manatus latirostris) inhabits a unique aquatic niche. Adaptations to this niche include obligate herbivory, low metabolic rate, large body size, and supernumerary teeth. Consequences of these adaptations are, cold intolerance, low population rate of increase, and range restrictions. Manatee life history traits also have influenced brain evolution. In the past, examination of only gross anatomical brain structures in manatee brains have led to the fallacy that manatee brains are poorly developed. In order to answer questions about the internal structure of the Florida manatee brain, cerebral isocortex, caudal to the lateral fissure, of the manatee brain was examined and its cytoarchitecture documented. It was found that the manatee brain is surprisingly complex. Cell counts and cortical thickness were measured in the manatee and other aquatic mammals in order to better understand the manatee’s place in brain evolution. Although manatees possess a small brain size relative to body size and a lissencephalic but unusually thick cerebral cortex, there is a high percentage of cerebral cortex to brain volume, and a highly organized cytoarchitecture which is differentiated into numerous cortical areas. Manatee brain characteristics appear to be on the same evolutionary adaptive level as dolphin brain characteristics. Functions for cortical areas defined in this study and in previous studies are suggested. However, due to the lack of electrophysiological data on manatees and a detailed examination of the manatee thalamus, functional assignments should be considered as preliminary contingent upon further study.

The purpose of this study was to compare the fish communities in mitigated and natural mangrove areas in the Port Everglades estuary. This study of fish recolonization of recently (ca. 5 years) planted mangrove forests, tested the null hypothesis that the species composition, size distribution and abundance of fish collected in natural, established and mitigated mangrove environments were the same. Two natural mangrove areas and two mitigated mangrove areas were used as study sites in John U. Lloyd Park. Two natural mangrove areas and two mitigated mangrove areas were used as study sites in West Lake Park. A variety of sampling gear types were utilized in the collection of fishes. Sampling was only done at low tide for all areas. Differences (chi square) in the abundances of fishes occurred between the natural mangrove sites in John U. Lloyd and West Lake Parks. These differences are thought to be due largely to differences in the hydrodynamic environment (i.e. tidal flushing, discharge rates of waterflow) and seasonality (i.e. month). However, differences between the fish communities in the mitigated areas of both parks were not significant at the 0.05 level of probability. Small fishes, the forage base for the larger piscivores, were equally represented in the mitigated sites throughout the study, and always dominated their respective communities numerically. Differences between natural and mitigated mangrove areas occurred in the distributions of transient species. In general, these transient fishes occurred only in the natural sites: the larval stage of one transient species, however, was found only in the mitigated sites. Likewise, within a species, smaller fishes were generally found in the mitigated sites and larger fishes were found in the natural sites. Thus, differences in the distributions of fishes between the mitigated and natural mangrove sites may be due to food availability as well as structural differences (i.e. spacing of plants) in each habitat. This study shows that mitigated mangrove forests are suitable habitats for small, forage species and presently there are differences in the fish populations in the natural and mitigated mangrove environments, the largest mangrove ecosystem remaining in Broward County.

Orcas, Orcinus orca, also known as "killer whales," are a species that have been the subject of long-term research. The aim of this study was to quantify percussive behaviors of a population of orcas, identify which individuals in a pod were displaying such behaviors, determine the context in which these behaviors occurred, and offer suggestions to the purpose, if any, that percussive activity may serve in this community. The study was conducted in Johnstone Strait, British Columbia, Canada during the summer months of 1992-1993. Observations were made during daylight hours. Whales were encountered either opportunistically, or by reports from other whale-watchers and researchers. A total of 542 hours of observational data were collected from 86 individual whales. Behavioral categories were defined as feeding, socializing, traveling, and resting. The most often observed percussive behaviors were tailslaps; they were therefore analyzed in the greatest detail. The number of tail slaps produced during feeding, socializing, aggregation, directional changes, and in the presence of boats were statistically compared. It has been suggested that calves and juveniles engage in percussive activity as a form of play during socializing, and that percussive behavior may aid in building physical strength and motor training. Adolescents and adults may engage in percussive actions to convey information about a direction change to other animals, strengthen social ties, express sociosexual behavior, and assist in social development, all of which could establish and strengthen social skills and social bonds among other individuals in the community. Other hypotheses for percussive behavior in this community include: forms of aggression; a type of warning signal; incidental occurrences due to elevated activity levels; a form of greeting among individuals; an expression of courtship behavior; a way to establish or re-establish dominant-subordinate relationships; an aid in the capture of prey during feeding; and a type of energy release either before or after resting behavior. It appears that each age class may have its own agenda for displaying percussive activity, depending on the context in which it was performed. The reason why each individual engages in percussive actions may be multifaceted for various situations, and each reason may not be bound to a particular context. The high level of occurrence of percussive behaviors implies that they are relevant to the daily activities of the northern resident community of orcas that inhabit the region of Johnstone Strait, British Columbia, Canada.

Time series of zooplankton concentrations and current velocities were collected with a bottom mounted (190 m) 307.2 kHz acoustic Doppler current profiler (ADCP) at the shelf break off Fort Lauderdale, Florida. Simultaneously, time series of temperature and salinity were collected with a moored CTD in the Port Everglades estuary approximately 4 km inshore of the ADCP mooring. Software was developed to extract acoustic volume scattering strength data (Vs) from the ADCP data stream. Vs is a relative measure of zooplankton concentration. In addition, eastward velocity and northward velocity data were collected from the ADCP. Data were recorded in two minute averages, with additional processing yielding hourly averages. Acoustic volume scattering strength and current velocity records from 176, 136, 95, and 56 m deep were isolated during post-processing for spectral analysis. The acoustic estimate of zooplankton concentration was found to be coherent with current velocity (both north and east components) at frequencies corresponding to the scales of Gulf Stream meanders (2-10 days per cycle) and diurnal and semi-diurnal tidal variability (24 and 12 hours per cycle, respectively). Estuarine salinity variations were also coherent with variability in circulation at the shelf break at the energetic periods of 24, 12, 8 and 6 hours per cycle. Estuarine salinity varied inversely with the distance of the Gulf Stream front from shore (0.5 - 6 week observation interval). Apparently, low frequency variability in the salinity of estuarine water is also associated with variability in the position of the Gulf Stream. It would appear that variability of Gulf Stream position and flow influences the cross-shelf transport of planktonic organisms, such as fish larvae, at a variety of temporal scales and thereby links offshore and estuarine ecosystems off southeast Florida.

Concentrations of methanesulfonate (MSA), nitrate (NO3-) and non-sea-salt sulfate (nssSO4-) were compared for five different air mass categories encountered during a 1993 NOAA cruise in the North Atlantic. NO3- and nssSO4- concentrations were highest during air masses originating from Europe and the United States. MSA concentrations increased with increasing latitude. Dry deposition fluxes for the three analytes were compared with respect to particle size and air mass category. MSA had a mixed distribution with particle size, nssSO4- was found primarily on smaller particles (<1.1 μm radius), and NO3- was found primarily on larger particles (≥ 1. 1 μm radius). With respect to air mass category, the highest dry deposition flux for the three analytes was found during sampled air with European continental influence. Total dry deposition fluxes (all particle sizes) were compared with previous studies in the North Atlantic with respect to air mass category. The NO3- and nssSO4- fluxes in this study are lower than those reported in the mid 1980's in both clean marine air and air masses originating from the United States. These differences are probably due to interannual variation. Atmospheric nitrogen deposition from air masses originating in the U.S., found during this study, was considerably lower than the minimum nitrogen requirement for new primary production expressed in previous studies.

No description available.

Cyclic variations in skeletal structure of long-lived reef corals produce annual density bands evident by X-radiography and X-ray computed tomography. The chemical composition of the calcium carbonate (CaCO3) skeleton and the chronological reliability of these high-density (HD) and low-density (LD) bands can provide accurate records for reconstruction of long-term climatic and ecological conditions. Due to variability across coral taxa, the architectural variations responsible for density banding are not completely understood. The western Atlantic/Caribbean reef coral, Diploria strigosa, is the first meandroid (brain) coral analyzed for skeletal variations relative to density band formation. Skeletal architecture analyses consisted of X-radiography, densitometry, X-ray computed tomography, and computer image analysis techniques. High-density bands correlated with thickened septa and tightly organized and thickened columella. Dissepiment spacing and colline thickness remained relatively constant between high and low-density bands. Results suggest that relationships between skeletal architecture and density banding for D. strigosa differ slightly from previously reported results for Montastraea and Porites. Skeletal structural analyses provide insights relative to density band formation and suggest D. strigosa is a good candidate for isotopic/trace element analyses and a recorder of long-term growth histories.

Tissue samples from twenty bottlenose dolphins from a stable, residential community of coastal dolphins in the western Gulf of Mexico were analyzed for toxic PCB congeners and chlorinated pesticides. The tissues analyzed (blubber and melon) were from known individuals in a long-term (27+ y) study that stranded and were recovered for necropsy. Substantial demographic data were available on these individuals and utilized in the analysis of maternal transfer of organochlorines to young. The male dolphins in this study were shown to accumulate organochlorine contaminants with age. In female dolphins the organochlorine levels were found to decline with age. These results are in agreement with previous studies, with gestational and lactational transfer accounting for the decline seen in the females. A lengthening in interreproductive interval by increasing organochlorine levels after approximately age 30 y is noted in the females. For the first time, this study quantified the organochlorine levels of the first calf of a female, testing the hypothesis that the first-born of a female receives a substantially greater organochlorine load than subsequent calves. The first-born calf (age 5.3 mo) had the highest blubber ΣPCB, total DDT, HCB, and total pesticide levels of all animals in this study. The organochlorine levels in this calf were 2-5 fold higher than in a similarly aged, fourth-born calf. All animals in this study had appreciable EPCBlevels (range 0.07 - 26.9 ug/g wet weight; 2.6 - 203.2 ug/g lipid weight), and EDDT (range 0.06 - 10.3 wet weight; 0.9 - 88.1 ug/g lipid weight). These values are in a moderate range compared to other studies, but not far below levels at which western Gulf of Mexico bottlenose dolphins evidenced mortality events in 1990 and 1992. Further monitoring of this population is warranted.

Blue tilapia, Oreochromis aureus were cultured from fingerling through maturation, in outdoor tanks, at varying salinities, for a period of nine months, from September 19, 1997 to June 19, 1998. Twelve tanks were used for testing four different salinities, with three replicates each. Each tank had a surface area of 0.8 m2, a water depth of 48cm, and held a volume of 350 liters. Each tank was stocked with ten O. aureus, with a total mean weight of 100 grams, and fed 5% to 10% body weight per day depending on size throughout the study. Salinity was the only induced variable throughout the experiment. Three tanks were the freshwater control group and salinity was held at 0 ppt. Salinities in three tanks were maintained at 10 ± 2ppt. Salinities in three tanks were maintained at 20 ± 2ppt and the salinities for the remaining three tanks were maintained at 30 ± 2ppt. Complete water changes were done each month, and the fish were individually weighed and an estimate of uneaten food was done. Any morphological or behavioral changes were noted for each fish, and each was regularly checked for eggs. During the ninth month, reproduction resulted in viable eggs occurring in the freshwater control group and two tanks with salinities of 10 ppt. Light orange colored eggs were found in the mouths of females in tanks with salinities of 20 ppt, but the eggs were not viable. The fish in one tank suffered a mass mortality in month seven, so it was removed from reproduction computations. Reproduction also occurred during the ninth month in the freshwater control groups. Light orange colored eggs were found in the mouths of females in tanks with salinities of 20 ppt, but the eggs were not viable. Eggs with a grayish tint were found in the mouths of females in tanks with salinities of 30 ppt, but the eggs were also not viable. One high salinity tank was removed after nine months due to disease, but females were holding eggs with a gray color and eggs were examined and found not to be viable. No reproduction occurred in tanks with salinities of 20 ppt or higher during the experiment. Weight gain was shown to be positive and linear with salinity. The control group had the least weight gain with a final mean weight gain of 565 grams per tank. In tanks with salinities of 10 ppt, final mean weight gain of the fish was 697 grams; and in tanks with water salinities of 20 ppt, a final mean weight gain of the fish was 815 grams at the close of the experiment. Fish within tanks with salinities of 30 ppt, showed the most gain, with a mean weight gain of 927 grams these differences were shown to be statistically significant (P< .004). Morphological changes and the occurrence of disease were evident between the fish in the control tanks and the fish in all other tanks. Tank 3, with 20 ppt salinity developed bacterial septicemia, caused by Streptococcus sp .. This disease produced some lesions, enlarged heads and sunken bellies as well as a dark green cast to the dorsal area. During the eighth month, the fish in a tank with salinity of 30 ppt developed a toxic algae bloom and the fish contracted a disease, which manifested itself by producing epithelial erosion, highly suggestive of the dinoflagellate pathogen Pfiesteria piscicida. Within a week, nine of the ten fish suffered severe epithelial loss and were close to death. Other changes accompanying increased salinity were brighter red flashing on the dorsal and pectoral fins and tail. Thus the results are consistent with a hypothesis that higher salinity severely restricts reproduction and increases growth rates, but it was also appears that increased disease accompanies increased salinity. Thus the use of saltwater does not appear to be advantageous for the culture of this species.