Charles A. Manire

Serological Changes Associated with Gill-Net Capture and Restraint in Three Species of Sharks

Abstract To investigate the biochemical effects of capture and restraint on sharks, 17 serum constituents were measured in three species (bonnethead shark Sphyrna tiburo, blacktip shark Carcharhinus limbatus, and bull shark C. leucas) after gill-net capture. The relative degree of capture effects on each animal was judged using an index of behavioral response devised for use in tag−recapture studies. Serum from each shark was assayed for glucose, creatinine, uric acid, sodium, chloride, potassium, inorganic phosphate, total and ionized calcium, total protein, albumin, globulin, alkaline phosphatase, lactate, lactate dehydrogenase, aspartate aminotransferase, and total iron. In addition, hematocrit was measured from whole blood for each shark. When correlated with the relative degree of capture effects, there were significant intraspecific changes in the concentration of potassium, lactate, inorganic phosphate, uric acid, alkaline phosphatase, aspartate aminotransferase, total and ionized calcium, and gluc...

Predominance of genetic monogamy by females in a hammerhead shark, Sphyrna tiburo: implications for shark conservation

There is growing interest in the mating systems of sharks and their relatives (Class Chondrichthyes) because these ancient fishes occupy a key position in vertebrate phylogeny and are increasingly in need of conservation due to widespread overexploitation. Based on precious few genetic and field observational studies, current speculation is that polyandrous mating strategies and multiple paternity may be common in sharks as they are in most other vertebrates. Here, we test this hypothesis by examining the genetic mating system of the bonnethead shark, Sphyrna tiburo, using microsatellite DNA profiling of 22 litters (22 mothers, 188 embryos genotyped at four polymorphic loci) obtained from multiple locations along the west coast of Florida. Contrary to expectations based on the ability of female S. tiburo to store sperm, the social nature of this species and the 100% multiple paternity observed in two other coastal shark species, over 81% of sampled bonnethead females produced litters sired by a single male (i.e. genetic monogamy). When multiple paternity occurred in S. tiburo, there was an indication of increased incidence in larger mothers with bigger litters. Our data suggest that sharks may exhibit complex genetic mating systems with a high degree of interspecific variability, and as a result some species may be more susceptible to loss of genetic variation in the face of escalating fishing pressure. Based on these findings, we suggest that knowledge of elasmobranch mating systems should be an important component of conservation and management programmes for these heavily exploited species.

Genomic characterization of two novel reptilian papillomaviruses, Chelonia mydas papillomavirus 1 and Caretta caretta papillomavirus 1

In this paper we describe the characterization of the genomes of two sea turtle papillomaviruses, Chelonia mydas PV (CmPV-1) and Caretta caretta PV (CcPV-1). The isolation and sequencing of the first non-avian reptilian PVs extend the evolutionary history of PVs to include all amniotes. PVs have now been described in mammals, birds and non-avian reptiles. The chelonian PVs form a distinct clade most closely related to the avian PVs. Unlike the avian PVs, both chelonian PVs have canonical E6 and E7 ORFs, indicating that these genes were present in the common ancestor to mammalian and non-mammalian amniote PVs. Rates of evolution among the non-mammalian PVs were generally slower than those estimated for mammalian PVs, perhaps due to lower metabolic rates among the ectothermic reptiles.

Genetic identification of novel poxviruses of cetaceans and pinnipeds

Summary.Novel poxviruses were identified in skin lesions of several species of cetaceans and pinnipeds using polymerase chain reaction targeting DNA polymerase and DNA topoisomerase I genes of members of the subfamily Chordopoxvirinae. With the exception of parapoxviruses, no molecular data of marine mammal poxviruses were available to infer genetic and evolutionary relatedness to terrestrial vertebrate poxviruses. Viruses were assigned to a cetacean poxvirus 1 (CPV-1) group based on nucleotide and amino acid identities of gene fragments amplified from skin lesions of Asian bottlenose (Tursiops aduncus), Atlantic bottlenose (Tursiops truncatus), rough-toothed (Steno bredanensis), and striped (Stenella coeruleoalba) dolphins. A different poxvirus was detected in skin lesions of a bowhead whale (Balaena mysticetus) and provisionally assigned to a CPV-2 group. These viruses showed highest identity to terrestrial poxviruses of the genera Orthopoxvirus and Suipoxvirus. A novel species-specific poxvirus was also identified in skin lesions of Steller sea lions (Eumetopias jubatus). None of these poxviruses were found to have amplifiable hemagglutinin gene sequences. Novel parapoxviruses were also identified in skin lesions of Steller sea lions and spotted seals (Phoca largha). A significant degree of divergence was observed in sequences of Steller sea lion parapoxviruses, while those of spotted seals and harbor seals (Phoca vitulina) were highly conserved.

Assessing mortality of released or discarded fish using a logistic model of relative survival derived from tagging data

Abstract The mortality of released or discarded fish in commercial and recreational fisheries and in fisheries-independent research is a critical area of study for contemporary fisheries science. Key questions involving postrelease survival include the following: What fraction of the bycatch discarded in a commercial fishery survives? What is the hooking mortality of fish released by recreational anglers, and how does this vary with the treatment and condition of the fish? What fraction of tagged fish do not survive the stress of capture and tagging? What percentage of hatchery-raised fish survive after stocking? To address these and related questions, we develop a two-step approach to estimating absolute postrelease survival rates. First, fish are tagged and assigned to discrete classes based on their condition (from best to worst) at release. The relative survival of fish released in different conditions is estimated from tag returns by fitting a logistic model. Then, assuming that fish in the best cond...

Disseminated Mycotic Infection Caused by Colletotrichum acutatum in a Kemp's Ridley Sea Turtle (Lepidochelys kempi)

ABSTRACT Colletotrichum acutatum is a cosmopolitan plant pathogen with a wide host range. While the organisms phytopathogenic potential has been well documented, it has never been reported as an etiologic agent of disease in either animals or humans. In this case, a juvenile Kemps ridley sea turtle, Lepidochelys kempi, probably with immune compromise following cold stunning (extended hypothermia), developed a disseminated mycotic infection in the lungs and kidneys. Prophylactic treatment with oral itraconazole did not prevent or cure the infection. This report of a Colletotrichum acutatum infection in an animal extends the range of disease caused by this organism beyond that of a phytopathogen.

Serum steroid hormones including 11‐ketotestosterone, 11‐ketoandrostenedione, and dihydroprogesterone in juvenile and adult bonnethead sharks, Sphyrna tiburo

Previous studies in the placental viviparous bonnethead shark, Sphyrna tiburo, have correlated 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone with reproductive events in both males and females. However, several key reproductive events, including implantation, maintenance of pregnancy, and parturition, did not correlate with these four steroid hormones. Therefore, the present study investigated three steroid hormones, 11-ketotestosterone, 11-ketoandrostenedione, and dihydroprogesterone, which have demonstrably important roles in the reproductive cycles of teleosts. It was hypothesized that one or more of these three hormones would correlate with specific reproductive events in S. tiburo. Concurrently, developmental (growth and/or maturation) analyses of these three steroids plus 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone were investigated in juvenile bonnethead sharks. Serum dihydroprogesterone concentrations were highest in mature females and 11-ketotestosterone concentrations were highest in mature males. In mature females, 11-ketoandrostenedione levels were elevated from the time of mating, through six months of sperm storage and another four months of gestation. At parturition concentrations became significantly lower and remained lower until mating occurred again in another two to three months. Serum 11-ketotestosterone concentrations were the highest at implantation though not significant. In mature males, significantly elevated serum levels of dihydroprogesterone occurred in April and May, near the start of annual testicular development. During growth in males, testosterone and dihydrotestosterone increased progressively and in females, testosterone increased progressively. At maturity in males, significant increases occurred in testosterone and 11-ketotestosterone concentrations while, in females, dihydroprogesterone, 11-ketotestosterone, 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone concentrations increased. This study shows that although testosterone may be the primary androgen in the bonnethead shark, other derived androgens may have important functions in growth, maturation, and reproduction. J. Exp. Zool. 284:595-603, 1999.

Use of Calcein as a Fluorescent Marker for Elasmobranch Vertebral Cartilage

Abstract The effectiveness of calcein as a fluorescent marker of elasmobranch vertebrae was examined in the nurse shark Ginglvmostotna cirratum. Intramuscular injection of calcein at a standard dosage of 25 mg/kg body weight (BW) produced distinct fluorescent marks in nurse shark vertebrae; however, it also induced physiological stress and mortality. Lower dosages of 10 and 5 mg/kg BW also produced chemical marks suitable for age validation but were not associated with animal death. These data suggest that calcein dosage levels recommended for teleost age validation may be toxic to elasmobranchs. Future studies should focus on the toxicity of lower-dosage calcein injections.

Spirorchiidiasis in stranded loggerhead Caretta caretta and green turtles Chelonia mydas in Florida (USA): host pathology and significance

Spirorchiid trematodes are implicated as an important cause of stranding and mortality in sea turtles worldwide. However, the impact of these parasites on sea turtle health is poorly understood due to biases in study populations and limited or missing data for some host species and regions, including the southeastern United States. We examined necropsy findings and parasitological data from 89 loggerhead Caretta caretta and 59 green turtles Chelonia mydas that were found dead or moribund (i.e. stranded) in Florida (USA) and evaluated the role of spirorchiidiasis in the cause of death. High prevalence of infection in the stranding population was observed, and most infections were regarded as incidental to the cause of death. Spirorchiidiasis was causal or contributory to death in some cases; however, notable host injury and/or large numbers of parasites were observed in some animals, including nutritionally robust turtles, with no apparent relationship to cause of death. New spirorchiid species records for the region were documented and identified genera included Neospirorchis, Hapalotrema, Carettacola, and Learedius. Parasites inhabited and were associated with injury and inflammation in a variety of anatomic locations, including large arteries, the central nervous system, endocrine organs, and the gastrointestinal tract. These findings provide essential information on the diversity of spirorchiids found in Florida sea turtles, as well as prevalence of infection and the spectrum of associated pathological lesions. Several areas of needed study are identified with regard to potential health implications in the turtle host, and findings caution against over-interpretation in individual cases.

STEADY-STATE PLASMA CONCENTRATIONS OF ITRACONAZOLE AFTER ORAL ADMINISTRATION IN KEMP'S RIDLEY SEA TURTLES, LEPIDOCHELYS KEMPI

Abstract Pharmacokinetic studies of antifungal agents in reptiles are uncommon. Itraconazole, which has been used prophylactically in juvenile sea turtles suffering from hypothermia (cold stunning) on a regular basis, was evaluated for steady-state plasma concentrations. Five Kemps ridley sea turtles (Lepidochelys kempi) receiving itraconazole at several dosages in a rehabilitation program had blood collected within 24 hr to estimate dosing frequency. Subsequently, serial blood samples of Kemps ridley sea turtles that were given itraconazole at several dosages for 30 days to treat cold stunning were collected at various intervals to evaluate itraconazole plasma concentrations. Tissue samples were collected from one Kemps ridley that died during rehabilitation. Plasma concentrations of itraconazole (and of hydroxyitraconazole [OH-ITRA], one of its major bioactive metabolites) were determined using a modified, validated reverse-phase high-performance liquid chromatography technique. Itraconazole concentrations in tissues were determined by bioassay to be far greater than the plasma concentrations measured in any of the turtles. At a 15-mg/kg dosage, the half-life (t1/2) was 75 hr for itraconazole and 55 hr for OH-ITRA. All dosages produced adequate concentrations in some turtles, but consistent therapeutic concentrations were produced only at 15 mg/kg q72hr and 5 mg/kg s.i.d., with the latter producing the highest plasma concentrations.