RNA-seq analysis of the gonadal transcriptome during Alligator mississippiensis temperature-dependent sex determination and differentiation

Annotation of development-dependent dimorphic genes in gonad during Day 0–12. Annotation of development-dependent significantly up- and down- regulated DEGs at FDR < 0.01 in gonadal regions incubated under MPT and FPT conditions during Day 0 to Day 12. Ordered by decreasing fold change. (XLSX 196 kb

Perfluorinated alkyl acids and fecundity assessment in striped mullet (\u3ci\u3eMugil cephalus\u3c/i\u3e) at Merritt Island national wildlife refuge

This study investigated wild caught striped mullet (Mugil cephalus) at Merritt Island National Wildlife Refuge (MINWR) for levels of 15 perfluoroalkyl acids (PFAA) in tandem with individual fecundity measurements (Oocyte sub-stage 2 late, n=42) and oocyte reproductive stages (Stages 1–5, n=128). PFAAmeasurementswere quantified in stripedmullet liver (n=128),muscle (n=49), and gonad (n=10). No significant negative impacts of liver PFAA burden on wild-caught,mullet fecundity endpoints were observed in this study; however, changes in PFAAwere observed in the liver asmullet progressed through different sub-stages of oocyte development. Of the PFAA with significant changes by sub-stage of oocyte development, the carboxylic acids (perfluorooctanoic acid, perfluorononanoic acid, and perfluorotridecanoic acid) increased in the liver with increasing sub-stage while the sulfonic acid and its precursor (perfluorooctanesulfonic acid (PFOS) and perfluorooctanesulfonamide, respectively) decreased in the liver with increasing sub-stage of oocyte development. This is a unique find and suggests PFAA change location of compartmentalization as mullet progress towards spawning. Investigations also revealed higher than expected median muscle and gonad levels of PFOS in striped mullet collected at MINWR (9.01 ng/g and 80.2 ng/g, respectively)

Factors affecting individual foraging specialization and temporal diet stability across the range of a large “generalist” apex predator

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability

Perfluorinated Alkyl Acids in Plasma of American Alligators (Alligator Mississippiensis) from Florida and South Carolina

This study aimed to quantitate fourteen perfluoroalkyl acids (PFAAs) in 125 adult American alligators at twelve sites across the southeastern US. Of those fourteen PFAAs, nine were detected in 65% - 100% of the samples: PFOA, PFNA, PFDA, PFUnA, PFDoA, PFTriA, PFTA, PFHxS, and PFOS. Males (across all sites) showed significantly higher concentrations of four PFAAs: PFOS (p = 0.01), PFDA (p = 0.0003), PFUnA (p = 0.021), and PFTriA (p = 0.021). Concentrations of PFOS, PFHxS, and PFDA in plasma were significantly different among the sites in each sex. Alligators at Merritt Island National Wildlife Refuge and Kiawah Nature Conservancy both exhibited some of the highest PFOS concentrations (medians 99.5 ng/g and 55.8 ng/g respectively) in plasma measured to date in a crocodilian species. A number of positive correlations between PFAAs and snout-vent length (SVL) were observed in both sexes suggesting PFAA body burdens increase with increasing size. In addition, several significant correlations among PFAAs in alligator plasma may suggest conserved sources of PFAAs at each site throughout the greater study area. This study is the first to report PFAAs in American alligators, reveals potential PFAA hot spots in Florida and South Carolina, and provides and additional contaminant of concern when assessing anthropogenic impacts on ecosystem health

The post-occipital spinal venous sinus of the Nile crocodile (Crocodylus niloticus) : its anatomy and use for blood sample collection and intravenous infusions

The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions.The Norwegian Council for Higher Education’s Programme for Development, Research and Education (NUFU 08/02) and the Royal Netherlands Embassy in South Africa (Prof. Nico Visser).http://www.jsava.co.zaam2014ab201

American Alligator Research on the Kennedy Space Center

This slide presentation reviews the research conducted at the Kennedy Space Center on the American Alligator. The objectives of the research were to establish life history baseline at the Kennedy Space Center and at the Merit Island National Wildlife Reserve (MINWR). Some of the factors that were examined are: nesting success, movement patterns, and population structure. Another objective was to determine the overall health of the alligator population, by analyzing blood and tissue chemistry, and urine analysis. A third objective was to compare alligators at KSC/MINWR to the statewide population. Some of the results are shown in charts and graphs

Perfluorinated alkyl acids and fecundity assessment in striped mullet (\u3ci\u3eMugil cephalus\u3c/i\u3e) at Merritt Island national wildlife refuge

This study investigated wild caught striped mullet (Mugil cephalus) at Merritt Island National Wildlife Refuge (MINWR) for levels of 15 perfluoroalkyl acids (PFAA) in tandem with individual fecundity measurements (Oocyte sub-stage 2 late, n=42) and oocyte reproductive stages (Stages 1–5, n=128). PFAAmeasurementswere quantified in stripedmullet liver (n=128),muscle (n=49), and gonad (n=10). No significant negative impacts of liver PFAA burden on wild-caught,mullet fecundity endpoints were observed in this study; however, changes in PFAAwere observed in the liver asmullet progressed through different sub-stages of oocyte development. Of the PFAA with significant changes by sub-stage of oocyte development, the carboxylic acids (perfluorooctanoic acid, perfluorononanoic acid, and perfluorotridecanoic acid) increased in the liver with increasing sub-stage while the sulfonic acid and its precursor (perfluorooctanesulfonic acid (PFOS) and perfluorooctanesulfonamide, respectively) decreased in the liver with increasing sub-stage of oocyte development. This is a unique find and suggests PFAA change location of compartmentalization as mullet progress towards spawning. Investigations also revealed higher than expected median muscle and gonad levels of PFOS in striped mullet collected at MINWR (9.01 ng/g and 80.2 ng/g, respectively)

Relationship between plasma triiodothyronine concentrations and plasma inorganic iodide concentrations of alligators.

<p>Merritt Island  =  black circles and black line, Lake Woodruff  =  white circles and dotted line, Lake Apopka  =  gray diamonds and gray line. A. Neonates B. Juveniles.</p

Plasma thyroid hormone concentrations from different sites and life stages of American alligators from Florida.

<p>Merritt Island  =  black, Lake Woodruff  =  white, Lake Apopka  =  gray. Letters represent statistical differences among sites within age groups. Numbers within bars represent sample size. Error bars are ± SE. A. Mean plasma thyroxine concentrations. B. Mean plasma triiodothyronine concentrations.</p