American alligator (Alligator mississippiensis) weight gain in captivity and implications for captive reptile body condition

The body condition of an animal is an indicator of health status and is dependent upon many factors, some of which can vary between wild and captive settings. Despite this, there have not been many studies on how captivity affects body condition relative to wild animal populations. This study explores the body condition of captive and wild American alligators (Alligator mississippiensis) because reptiles are frequently overlooked in studies of captive animal health and because alligators are well-represented in captivity. We collected body condition data from 209 captive alligators and 935 wild alligators throughout Florida and southeastern Georgia and compared the relationships between body condition and body length for each group. We found that captive alligators exhibited significantly higher body condition values as they aged, and that this result was driven by the difference between captive and wild males. Body condition values for captive juveniles did not differ from wild juveniles, but they differed when comparing adults. Our results suggest that factors such as diet and movement rates play major roles in determining alligator body condition and that body condition may be an important metric for monitoring captive alligator health, especially for older adult males.     

Peat accretion and phosphorus accumulation along a eutrophication gradient in the northern Everglades

Recent rates of peat accretion (as determined by¹³⁷Cs) and N, P, organic C, Ca and Na accumulation were measured along a 10 km eutrophication gradient in the northern Everglades area of Water Conservation Area 2A (WCA 2A) that has received agricultural drainage from the Hillsboro canal for the past 25–30 yrs. Rates of peat accretion were highest at sampling locations closest to the Hillsboro canal, 1.6 km downstream, (5.67 ± 0.50 mm/yr) and decreased to 2.01 ± 0.31 mm/yr at distances of 7.1 to 10.7 km downstream. Phosphorus and Na accumulation were a function of both peat accretion and soil P and Na concentrations. The concentration and accumulation of P in peat deposited in the past 26 years was highest near the Hillsboro canal (1478 ± 67 ug/g, 0.66 ± 0.06 g/m²/yr) and decreased to 560 ± 20 ug/g and 0.10 ± 0.02 g/m²/yr at distances of 8.8 to 10.7 km downstream. Like phosphorus, the concentration and rate of Na accumulation was highest near the Hillsboro canal (3205 ± 1021 ug/g, 1.48 ± 0.53 g/m²/yr). Although sodium enrichment of the peat was limited to 1.6 km downstream of the Hillsboro canal, increased rates of Na accumulation penetrated 5.2 km downstream of the Hillsboro canal, the extent of the area of enhanced peat accretion. In contrast to P and Na, there was no difference in the concentration of soil organic C, N and Ca along the eutrophication gradient. However, there was a gradient of organic C, N and Ca accumulation corresponding to the area of enhanced peat accretion. The highest rates occurred 1.6 km south of the Hillsboro canal (212 ± 5 g organic C/m²/yr, 14.1 ± 0.4 g N/m²/yr, 22.1 ± 5.2 g Ca/m²/yr). Accumulation of organic C, N and Ca at distances of 7.1–10.7 km downstream averaged 87 ± 11, 6.3 ± 0.7 and 6.5 ± 0.9 g/m²/yr, respectively. The areal extent of enhanced peat accretion and organic C, N, Ca and Na accumulation encompasses approximately 7700 ha of the northern part of WCA 2A. The area of enhanced P accumulation is larger, covering 11,500 ha or 26% of the total area of WCA 2A. The 11,500 ha area has functioned as a sink for P for the past 25–30 yr removing 74% (49.3 MT/yr) of the 67 MT/yr that enters via agricultural drainage and rainfall. Moreover, P accumulation along the gradient was related to mean (1989–1990) surface water P concentration, decreasing as surface water P decreases. These findings suggest that P accumulation is dependent on the P concentration in the water column and that decreasing P loadings per unit area result in less P storage per unit area. The potential longterm equilibrium of the 11,500 ha area as a sink for P is based on a mean annual loading of 67 metric tons P/yr. Input rates exceeding this loading rate could result in an expansion of the 11,500 ha area until a new equilibrium size is reached.     

OBSERVATIONS OF FLORIDA MANATEES(TRICHECHUS MANATUS LATIROSTRIS) AROUND SELECTED POWER PLANTS IN WINTER

Sixty-four aerial surveys were flown during cold, winter weather between December 1982 and February 1772 to provide an index of trends in abundance of the Florida manatee ( Trichechus manatus latirostris )around five Florida Power & Light Company (FPL) plants. The surveys documented high winter use of warm-water discharges at four of the plants (Canaveral, Riviera. Port Everglades, and Fort Myers). The total number of manatees sighted at the five primary plants surveyed during a single survey ranged from 6 to 765 manatees (= 330 ± 45 manatees per survey): thus, up to 41% of the total Florida manatee minimum population of 1.850 animals may be found on cold days at FPL plants. The number of calves sighted at the plants during winter has decreased; similarly, for three consecutive years (winter 1989–1970 through winter 1991–1992), the percentage of the manatees that are calves sighted at the plants has decreased. Although data from the surveys of FPL plants do not necessarily reflect what may be happening with manatees located elsewhere in Florida, a possible reduction in calf numbers, coupled with increasing numbers of dead calves being documented by scientists involved in manatee carcass salvage work, is cause for concern in this slow-reproducing, endangered species.     

Effect of polyamines on the electrokinetic properties of red blood cells.

At the physiological pH 7.4, the zeta potential of the normal red blood cell in 1.5% glycine buffer was found to be ?52 mv, whereas that of sickling erythrocytes is ?45 mv. Addition of spermidine to normal red blood cells reduced the zeta potential by approximately 20 mv. In sickling red blood cells, where the polyamine content is determined to be 5 to 6 times greater than in the normal erythrocyte, addition of spermidine reduced the zeta potential by only 5 mv, indicating that little more polyamine binding occurs. The polyamine content of whole blood taken from 24 patients having sickle cell anemia was found to be more than ten times that of whole blood from normal donors. Binding of polyamines to the normal red blood cell was analyzed from the surface charge potential variation as a function of polyamine concentration and the apparent binding constant determined to be 130 d1/g. The difference in the electrokinetic properties of normal and sickling red blood cells in this system may be attributed, in part, to a variation in the polyamine content of the two types of erythrocytes.     

Protein synthesis and degradation in cultured muscle is altered by a phorbol diester tumor promoter

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) was observed to influence the relative rates of synthesis and degradation of several polypeptides in cultured chick embryo myotubes. The direction of influence partially correlated with whether the polypeptide was uniquely expressed in myotubes or also expressed in its proliferating precursors. The synthesis of all but one of the eight myotube-unique polypeptides examined was inhibited and the degradation of all but two was stimulated. The exceptions were intermediate filament subunits. In contrast, the metabolism of several non-myotube-unique polypeptides was either unaffected or influenced in the opposite direction. A method involving saturation of the intracellular leucine precursor pool with extracellular radioactive leucine suggested that the absolute rate of protein synthesis was only minimally, if at all, affected by the promoter. The effects on protein synthesis were at least partially reversible following removal of the promoter. The changes in synthesis and degradation did not reflect normal maturational changes in cultured myotubes and thus they appeared to be induced by TPA. The data suggest that under some circumstances the rates of synthesis and degradation of several proteins are inversely coupled in the myotube. They also provide a partial explanation for earlier ultrastructural observations that TPA caused a loss of myofilaments and an accumulation of intermediate filaments. Since myotubes occupy the G₁ (or G₀) stage of the cell cycle, and the DNA content of the cultures was not affected by TPA, TPA's effects were not mediated through cell cycle-dependent mechanisms.     

Waterbirds as indicators of ecosystem health in the coastal marine habitats of southern Florida: 1. Selection and justification for a suite of indicator species

The coastal marine environment is currently under threat from many anthropogenic pressures that were identified by the MARES project. Indicators of ecosystem health are needed so that targets can be set to guide protection and restoration efforts. Species of birds that are dependent on coastal habitats are ubiquitous along the coasts of southern Florida. Generally referred to as waterbirds, these species, although not all taxonomically related, share a common dependency on the marine environment for food, nesting habitat, or both. A suite of waterbirds was selected based on their perceived sensitivity to pressures in multiple coastal habitat types. The list of species was refined on the basis of a review of life history for characteristics that might make the species particularly vulnerable. Each selected species was then evaluated for sensitivity to the identified pressures using a hierarchical assessment that took into account the sensitivity, severity, and the temporal and spatial scales of the indicator to the given pressures. The selected suite of indicators was collectively sensitive to all the pressures except one.     

Laboratory and field evaluation of insect repellents as oviposition deterrents against the mosquito Aedes albopictus

Three experimental approaches were used to evaluate the oviposition deterrency of three insect repellents, AI3-35765, AI3-37220 (piperidine compounds), and the standard N,N-diethyl-3-methylbenzamide (deet) to the mosquito Aedes albopictus Skuse (Diptera: Culicidae). Against laboratory-reared Ae. albopictus gravid females, the EC50 values of AI3-37220, AI3-35765 and deet were 0.004%, 0.008% and 0.011% in laboratory cages and 0.004%, 0.01% and 0.009% in an outdoor screened cage. For a natural population of Ae. albopictus tested in the field, the EC50 values were determined as 0.004%, 0.008% and 0.001%, respectively. Ageing concentrations of 0.1% of each repellent provided >50% effective oviposition deterrency against the laboratory population of Ae. albopictus for 13 days in laboratory cages, for 15 days in the outdoor cage, and for 21 days against field population of Ae. albopictus in Florida. These topical skin repellents are effective oviposition deterrents for Ae. albopictus when employed at relatively low application rates.     

Population and conservation genetics of the gopher tortoise (<Emphasis Type="Italic">Gopherus polyphemus</Emphasis>)

The gopher tortoise (Gopherus polyphemus) is an important member of the sandhill, longleaf pine, and scrub ecosystems in the southeastern United States. Even though it is currently protected throughout its range, tortoise populations continue to decline. We assessed genetic diversity at nine microsatellite loci in 300 individuals from 21 locations throughout Florida and southern Georgia. Tortoise populations are clearly subdivided into at least eight genetic assemblages with an . Furthermore, we found indications of anthropogenic effects in the form of population bottlenecks in five populations and putative admixture in four. From these data, we recommend that the populations be managed to maintain existing genetic structure without further isolation of populations and the establishment of a holistic␣database to include genetic and demographic information useful for relocation and management purposes.     

Spanish colonial effects on Native American mating structure and genetic variability in northern and central Florida: Evidence from Apalachee and western Timucua

Standard population genetic analyses are implemented for a series of precontact and contact period samples from central and northern Florida to investigate changes in genetic variability and population affinity coincident with the establishment of Spanish missions during the 17th century. Estimates of F(ST) based on odontometric data indicate limited heterogeneity for the Apalachee samples, suggestive of some degree of within-group endogamy for this ethnic group prior to contact. This corresponds well with ethnohistoric reconstructions indicating that Apalachee were populous, partially linguistically isolated from its neighbors, and involved in persistent cycles of warfare with neighboring groups. Estimates of extralocal gene flow for the Apalachee samples indicate limited initial changes in the mating structure of these populations. After 1650, however, extralocal gene flow increases, consistent with evidence for dramatic population movements throughout northern Florida and increased Spanish presence in the province, particularly at the mission of San Luis. Inclusion of non-Apalachee outgroups does not increase estimates of genetic heterogeneity, as was expected based on ethnohistoric data. The pattern of genetic distances suggests a biological division between north and south Florida population groups, consistent with archaeological and ethnohistoric data, and similarly indicates some distinction between precontact and postcontact local groups. Differential extralocal gene flow experienced by pre-1650 Apalachee and Timucua populations suggests localized mission experience. The Apalachee, with large, dense populations, experienced limited initial changes in genetic diversity or mating structure. However, after 1650 they were apparently involved in a much more expansive mating network that may have included Spaniards and immigrant Native American groups to the region. These results are in contrast to the mission experience of the Guale Indians of the Georgia coast.