Spatial and temporal variability in the relative contribution of king mackerel (Scomberomorus cavalla) stocks to winter mixed fisheries off South Florida

King mackerel (Scomberomorus cavalla) are ecologically and economically important scombrids that inhabit U.S. waters of the Gulf of Mexico (GOM) and Atlantic Ocean (Atlantic). Separate migratory groups, or stocks, migrate from eastern GOM and southeastern U.S. Atlantic to south Florida waters where the stocks mix during winter. Currently, all winter landings from a management-defined south Florida mixing zone are attributed to the GOM stock. In this study, the stock composition of winter landings across three south Florida sampling zones was estimated by using stock-specific otolith morphological variables and Fourier harmonics. The mean accuracies of the jackknifed classifications from stepwise linear discriminant function analysis of otolith shape variables ranged from 66−76% for sex-specific models. Estimates of the contribution of the Atlantic stock to winter landings, derived from maximum likelihood stock mixing models, indicated the contribution was highest off southeastern Florida (as high as 82.8% for females in winter 2001−02) and lowest off southwestern Florida (as low as 14.5% for females in winter 2002−03). Overall, results provided evidence that the Atlantic stock contributes a certain, and perhaps a significant (i.e., ≥50%), percentage of landings taken in the management-defined winter mixing zone off south Florida, and the practice of assigning all winter mixing zone landings to the GOM stock shoul

Limited Activity Of Miltefosine In Murine Models Of Cryptococcal Meningoencephalitis And Disseminated Cryptococcosis

Miltefosine is an alkyl phosphocholine with good oral bioavailability and in vitro activity against Cryptococcus species that has gained interest as an additional agent for cryptococcal infections. Our objective was to further evaluate the in vivo efficacy of miltefosine in experimental in vivo models of cryptococcal meningoencephalitis and disseminated cryptococcosis. Mice were infected intracranially or intravenously with either C. neoformans USC1597 or H99. Miltefosine treatment (1.8 to 45 mg/kg of body weight orally once daily) began at either 1 h or 1 day postinoculation. Fluconazole (10 mg/kg orally twice daily) or amphotericin B deoxycholate (3 mg/kg intraperitoneally once daily) served as positive controls. In our standard models, miltefosine did not result in significant improvements in survival or reductions in fungal burden against either C. neoformans isolate. There was a trend toward improved survival with miltefosine at 7.2 mg/kg against disseminated cryptococcosis with the H99 strain but only at a low infecting inoculum. In contrast, both fluconazole and amphotericin B significantly improved survival in mice with cryptococcal meningoencephalitis and disseminated cryptococcosis due to USC1597. Amphotericin B also improved survival against both cryptococcal infections caused by H99. Combination therapy with miltefosine demonstrated neither synergy nor antagonism in both models. These results demonstrate limited efficacy of miltefosine and suggest caution with the potential use of this agent for the treatment of C. neoformans infections.Pharmac

Habitat and bycatch effects on population parameters of inshore lizardfish (Synodus foetens) in the north central Gulf of Mexico

We examined the effect of habitat and shrimp trawl bycatch on the density, size, growth, and mortality of inshore lizardfish (Synodus foetens), a nonexploited species that is among the most widespread and abundant benthic fishes in the north central Gulf of Mexico. Results of quarterly trawl sampling conducted from spring 2004 through spring 2005 revealed that inshore lizardfish are most abundant on sand habitat, but larger fish are more common on shell rubble habitat. There was no significant difference in fish density between habitats exposed to shrimp trawling on the open shelf versus those habitats within a permitted artificial reef zone that served as a de facto no-trawl area; this finding indicates that either inshore lizardfish experienced minimal effects from trawling or, more likely, that fish moved between trawled and nontrawled habitats. Exploitation ratio (bycatch mortality/total morality) estimates derived from catch curve analysis ranged from 0.43 inside the artificial reef zone to 0.55 outside the reef zone, thus indicating that inshore lizardfish are subject to significant fishing mortality in the north central Gulf of Mexico despite the lack of a directed fishery for the species. We infer from this result that effects of shrimp trawl bycatch may be significant at the population level for nonexploited species and that a broader ecosystem-scale examination of bycatch effects is warranted

Do Vertebral Chemical Signatures Distinguish Juvenile Blacktip Shark (Carcharhinus limbatus) Nursery Regions in the Northern Gulf of Mexico?

Identifying and protecting shark nurseries is a common management strategy used to help rebuild overfished stocks, yet we know little about connectivity between juvenile and adult populations. By analysing trace metals incorporated into vertebral cartilage, it may be possible to infer natal origin based on nursery-specific chemical signatures. To assess the efficacy of this approach, we collected juvenile blacktip sharks (Carcharhinus limbatus; n = 93) from four regions in the Gulf of Mexico in 2012 and 2013 and analysed their vertebral centra with laser ablation-inductively coupled plasma-mass spectrometry. We observed significant regional differences in six element : Ca ratios in both 2012 and 2013. Multi-element chemical signatures were significantly different among regions and between year-classes. Year-class-specific linear discriminant function analysis yielded regional classification accuracies of 81% for 2012 and 85% for 2013, although samples were not obtained from all four regions in 2012. Combining year-classes resulted in an overall classification accuracy of 84%, thus demonstrating the usefulness of this approach. These results are encouraging yet highlight a need for more research to better evaluate the efficacy of vertebral chemistry to study elasmobranch population connectivity

A Deep Proper-Motion Survey in Kapteyn Selected Areas: I. Survey Description and First Results for Stars in the Tidal Tail of Sagittarius and in the Monoceros Ring

We describe a high-precision, deep (to V ~ 19-21) absolute proper-motion survey that samples ~50 lines of sight in the Kapteyn Selected Areas along declination zones -15, 0 and 15 degrees. In many fields the astrometric baseline reaches nearly a century. We demonstrate that these data provide typical per star precisions between ~ 1 and 3 mas/yr to the above magnitude limits, with the absolute reference frame established by numerous extragalactic sources in each survey field. Combined with existing and ongoing photometric and radial velocity surveys in these fields, these astrometric data will enable, among other things, accurate, detailed dynamical modeling of satellite interactions with our Galaxy. In this contribution we describe the astrometric part of our survey and show preliminary results along the trailing tail of the Sagittarius dwarf galaxy, and in the Monoceros ring region.Comment: Accepter for publication in the Astronomical Journa

Discrimination of Juvenile Red Snapper Otolith Chemical Signatures from Gulf of Mexico Nursery Regions

Age-0 red snapper Lutjanus campechanus from the 2005-2007 year-classes were sampled in six regions across the Gulf of Mexico (Gulf) to develop nursery signatures from otolith element : Ca ratios (Ba:Ca, Mg:Ca, Mn:Ca, Sr:Ca, and Li:Ca) and stable isotope delta values (delta C-13 and delta O-18). Element : Ca ratios were analyzed with sector field inductively coupled plasma mass spectrometry on dissolved right sagittae; isotope ratio mass spectrometry was employed to analyze pulverized left otoliths for delta C-13 and delta O-18. Otolith chemical signatures were significantly different among regions in each year. Year-class-specific quadratic discriminant function analysis (QDFA) distinguished nursery regions with an accuracy of 82% for 2005, 70% for 2006, and 72% for 2007. However, samples were not obtained from all six study regions in 2005 and 2006. A QDFA of all year-classes combined produced an overall classification accuracy of 70%, thus indicating that region-specific otolith chemical signatures from adjacent sampling years could be used as surrogates for regions where samples were not obtained in a given year

Validation of Annual Growth-Zone Formation in Gray Triggerfish Balistes capriscus Dorsal Spines, Fin Rays, and Vertebrae

The goal of this study was to validate annual growth-zone formation in the gray triggerfish Balistes capriscus dorsal spines, fin rays, and vertebrae. Adult gray triggerfish (n = 4) were chemically marked by injecting with 50 mg of oxytetracycline (OTC) per kilogram body mass and reared in a 2,300-liter aquaculture tank. Fish were exposed to ambient light and water temperature mimicked bottom temperatures observed at an approximately 30-m depth in the northern Gulf of Mexico. Fish died after 262 d and their first dorsal spines, pectoral fin rays, and vertebrae were extracted and sectioned. One translucent zone formed distal to the OTC mark in all hardpart types during the study period. Additional fin rays and vertebrae with corresponding dorsal spines were sampled from fish (n = 27 and 59, respectively) during fishery-independent surveys to compare translucent zone counts between hardparts. There was a significant difference between translucent zone counts between fin ray and dorsal spine sections (tdf = 1,25 = 23.15, P = 0.004). Fin ray counts on average were one zone greater than dorsal spine counts. Translucent zone counts in vertebrae were similar to those counted in dorsal spines with no significant difference between structures (tdf = 1,57 = 1.90, P = 0.062). The percentage of dorsal spines with translucent margins increased in winter months, peaking in February, and dropped to the lowest values in summer. The combined results of this study validate annual translucent zone formation in gray triggerfish hardparts, with dorsal spines being the preferred ageing structure for production ageing

Otolith Microchemical Fingerprints of Age-0 Red Snapper, Lutjanus campechanus, from the Northern Gulf of Mexico

Red snapper, Lutjanus campechanus, in the northern Gulf of Mexico (Gulf) are believed to constitute a single stock. However, tagging and genetics studies suggest there is little mixing between populations of red snapper in the northern Gulf, and little is known about mixing rates of adult fish. The long-term goal of our work is to determine if age-0 red snapper from different nursery areas have unique microchemical fingerprints in their sagittal otoliths, and if so, can the microchemical fingerprints at the core of adult otoliths be used to determine retrospectively nursery area of origin. Ultimately, we hope to use the microchemical fingerprints at the core of adult snapper otoliths to estimate adults\u27 mixing rates and movement patterns. In this study, the objective was to determine if age-0 red snapper collected from different northern Gulf nursery areas in summer and fall 1995 did contain unique microchemical fingerprints. Sagittal otoliths of age-0 red snapper collected off the coasts of Alabama/Mississippi, Louisiana, and Texas were analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Twelve elements in the sagittae of age-0 snapper were analyzed with ICP-AES. Of these, eight were put into a stepwise discriminant function analysis with the best-fitted model including Mg, Se, As, Fe, and AI, entered in that order (MANOVA, P \u3c 0.001). Cross-validated classification accuracies were 92% for Texas fish, 91% for Louisiana fish, and 92% for Alabama/Mississippi fish. Therefore, it appears that otolith microchemistry can be used to infer nursery area of age-0 red snapper. Future work will focus on (1) establishing the temporal stability of age-0 red snapper otolith microchemical fingerprints and (2) inclusion of analyses of age-structured samples from adult red snapper otolith cores to estimate their nursery area of origin and mixing rates