| water quality influences reproduction in female mosquitofish (gambusia holbrooki) from eight florida springs. | contamination of freshwater ecosystems with nitrate is a growing global concern. although nitrate pollution is recognized as a cause of aquatic eutrophication, few studies have examined the possible physiological impacts of nitrate exposure. in this study, we surveyed several reproductive variables of viviparous female gambusia holbrooki (poeciliidae) captured from eight springs in florida. the eight springs represent a gradient of nitrate contamination (1-5 mg/l nitrate-nitrogen). we had two ob ... | 2006 | 16818249 |
| temporal population genetic structure of eastern mosquitofish in a dynamic aquatic landscape. | we analyzed the effect of periodic drying in the florida everglades on spatiotemporal population genetic structure of eastern mosquitofish (gambusia holbrooki). severe periodic drying events force individuals from disparate sources to mix in dry season relatively deep-water refuges. in 1996 (a wet year) and 1999 (a dry year), we sampled mosquitofish at 20 dry-season refuges distributed in 3 water management regions and characterized genetic variation for 10 allozyme and 3 microsatellite loci. in ... | 2011 | 21885573 |
| exposure to paper mill effluent at a site in north central florida elicits molecular-level changes in gene expression indicative of progesterone and androgen exposure. | endocrine disrupting compounds (edcs) are chemicals that negatively impact endocrine system function, with effluent from paper mills one example of this class of chemicals. in florida, female eastern mosquitofish (gambusia holbrooki) have been observed with male secondary sexual characteristics at three paper mill-impacted sites, indicative of edc exposure, and are still found at one site on the fenholloway river. the potential impacts that paper mill effluent exposure has on the g. holbrooki en ... | 2014 | 25198161 |
| androstenedione and progesterone in the sediment of a river receiving paper mill effluent. | the fenholloway river near perry, florida, receives effluent from a paper mill and contains populations of masculinized female eastern mosquitofish, gambusia holbrooki. a previous study identified the androgen precursor androstenedione at a low concentration (0.14 nm) in water samples from the river. the present study makes use of a toxicity identification and evaluation approach that includes solid phase extraction and high pressure liquid chromatography purification, androgen receptor transcri ... | 2003 | 12700410 |
| disturbed sexual characteristics in male mosquitofish (gambusia holbrooki) from a lake contaminated with endocrine disruptors. | previous laboratory studies have demonstrated that estrogenic and antiandrogenic chemicals can alter several sexual characteristics in male poeciliid fishes. whether similar disturbances occur under field conditions remains to be confirmed. lake apopka, florida, is contaminated with numerous chemicals, some of which possess endocrine-disrupting activity. male mosquitofish (gambusia holbrooki) were collected monthly from december 2000 through may 2001 from lake apopka and two nearby reference lak ... | 2003 | 12727596 |
| predation and the persistence of melanic male mosquitofish (gambusia holbrooki). | the empirical reasons for the persistent rarity of a genotype are typically complex and tedious to identify, particularly in nature. yet rare morphs occur in a substantial fraction of phenotypic polymorphisms. a colour polymorphism has persisted for decades in the eastern mosquitofish, yet why this is so remains obscure. here, i report the results of (1) intensive sampling at 45 natural sites to obtain the frequency distribution of the melanic (black) mosquitofish morph in florida, (2) predation ... | 2004 | 15149409 |
| reproductive characteristics of male mosquitofish (gambusia holbrooki) from nitrate-contaminated springs in florida. | over the past five decades, anthropogenic nitrate contamination has increased significantly in many ground and surface water systems, creating the need to understand how nitrate impacts the physiology of aquatic animals. we collected adult male mosquitofish (gambusia holbrooki) from eight springs in florida with varying nitrate concentrations (0.2-5.1 mg/l no(3)-n). fish were evaluated for spring-related differences in body, liver, and gonad size, gonopodium length, muscle testosterone and 11-ke ... | 2007 | 17767965 |
| prevalence of eustrongylides ignotus in mosquitofish (gambusia holbrooki) in florida: historical and regional comparisons. | we examined mosquitofish (gambusia holbrooki) caught between january 1990 and december 1991 from 24 sites in northern florida (usa), and preserved specimens collected from 32 sites throughout florida between 1930 and 1978, for presence of the larval nematode eustrongylides ignotus. we found 10 (42%) of the 24 recently-sampled sites in northern and central florida had at least one larval nematode present in the fish; combining these data with results of previous work, 11 (15%) of 75 recently samp ... | 1996 | 8827688 |
| epizootiology of eustrongylides ignotus in florida: transmission and development of larvae in intermediate hosts. | under laboratory conditions, 2 modes of transmission of eustrongylides ignotus (nematoda: dioctophymatoidea) to fish were identified. eastern mosquitofish (gambusia holbrooki) became infected after ingestion of either eggs of e. ignotus containing first-stage larvae or aquatic oligochaetes (limnodrilus hoffmeisteri) containing third-stage larvae of e. ignotus. after removal from the uterus of gravid e. ignotus females and incubation for 17-28 days, depending on temperature, it was found that par ... | 2003 | 12760643 |
| seasonal reproductive patterns of female gambusia holbrooki from two florida lakes. | lake apopka in central florida (usa) is significantly contaminated with a variety of chemicals including anthropogenic nutrients, organochlorine pesticides like dichlorodiphenyltrichloroethane (ddt) and dichlorodiphenyldichloroethylene (dde), and multiple congeners of polychlorinated biphenyls (pcbs). our laboratory has previously documented a number of reproductive abnormalities in alligators from lake apopka, compared with alligators captured from lake woodruff, a nearby reference lake. we con ... | 2010 | 20083296 |
| seasonal reproduction of male gambusia holbrooki (eastern mosquitofish) from two florida lakes. | sixteen monthly collections of adult male gambusia holbrooki (eastern mosquitofish) were obtained from two lakes in central florida, usa. lake woodruff and lake apopka are 36 miles apart, but differ in several environmental parameters. compared with lake woodruff, lake apopka is warmer, more shallow in sampling areas (particularly during drought conditions; approximately 15-90 cm in lake apopka versus 60-120 cm in lake woodruff), more turbid, and more heavily contaminated with nutrients and indu ... | 2013 | 23404634 |
| in vivo assessment of the capacity of androstenedione to masculinize female mosquitofish (gambusia affinis) exposed through dietary and static renewal methods. | in this study, we investigated the capacity of androstenedione to masculinize female mosquitofish. previous studies have identified androstenedione in the water and sediment of the fenholloway river, a florida, usa, coastal river that receives paper mill effluent and contains masculinized eastern mosquitofish (gambusia holbrooki). females of the closely related western mosquitofish, gambusia affinis, were exposed to androstenedione through both dietary and static renewal treatments. morphologica ... | 2007 | 17521138 |
| predation of mansonia (diptera: culicidae) by native mosquitofish in southern florida. | in experimental tanks and wading pools, the mosquitofish gambusia holbrooki reduced densities of mansonia larvae which, because of their attachment to the roots of aquatic plants, have been regarded previously as relatively impervious to predation. exoskeletal remains of larval mansonia were recovered from 43.5% of stomachs dissected from g. holbrooki, but not from heterandria formosa (least killifish) collected from two undisturbed ponds covered with water lettuce (pistia stratiotes l.). after ... | 1992 | 1495036 |
| identification of androstenedione in a river containing paper mill effluent. | effluent from a paper mill discharging into the fenholloway river, taylor county, florida, usa, contains chemicals that masculinize females of the resident population of eastern mosquitofish (gambusia holbrooki), as evidenced in females by elongated anal fins, which is normally a male-specific trait. to identify androgenic components in the effluent, water collected from the fenholloway river and a control tributary was fractionated using solid-phase extraction and reverse-phase high-performance ... | 2001 | 11392143 |
| using data from an encounter sampler to model fish dispersal. | a method to estimate speed of free-ranging fishes using a passive sampling device is described and illustrated with data from the everglades, u.s.a. catch per unit effort (cpue) from minnow traps embedded in drift fences was treated as an encounter rate and used to estimate speed, when combined with an independent estimate of density obtained by use of throw traps that enclose 1 m(2) of marsh habitat. underwater video was used to evaluate capture efficiency and species-specific bias of minnow tr ... | 2011 | 21284631 |
| ecological risk of methylmercury in everglades national park, florida, usa. | dramatic declines in mercury levels have been reported in everglades biota in recent years. yet, methylmercury (mehg) hot spots remain. this paper summarizes a risk assessment of mehg exposure to three piscivorous wildlife species (bald eagle, haliaeetus leucocephalus; wood stork, mycteria americana; and great egret, ardea albus) foraging at a mehg hot spot in northern everglades national park (enp). available data consisted of literature-derived life history parameters and tissue concentrations ... | 2008 | 18679795 |
| effects of salinity on native estuarine fish species in south florida. | variable and high salinities have been identified as key stressors in florida bay. the comprehensive everglades restoration plan (cerp) includes water redistribution projects that are intended to restore natural freshwater flows to northeastern florida bay. the present salinity regimes in the area, which span from hypo- to hypersaline, will be altered as a result of these actions. this research examined biological performance measures (i.e., growth and survival) of estuarine fish under varying s ... | 2008 | 18642076 |
| epizootiology of eustrongylides ignotus in florida: distribution, density, and natural infections in intermediate hosts. | a total of 63,451 fish, representing 39 species, was collected from 176 foraging sites used by ciconiiform wading birds in peninsular florida (usa) and examined for larvae of eustrongylides ignotus. infected fish were identified from 30 (17%) of the sites, all of which had been altered by human disturbance such as removal of sediment to construct ditches and dikes, improve water flow, or increase storage capacity and had a history of receiving anthropogenic nutrients such as sewage effluent, urb ... | 2002 | 12238365 |