Multiple-phase biometric relationships and sexual maturity in the atlantic bluefin tuna, thunnus thynnus (Osteichthyes: Scombridae)

Most fish undergo distinct growth phases during ontogenesis. An extremely important passage from the juvenile to adult phase occurs at the onset of sexual maturity, which shows in body proportion and/or growth rate changes. These can be detected as change-points in biometric relationships. In this paper, the Atlantic bluefin tuna was analyzed to verify whether its somatic proportions show any sign of discontinuity during growth, i.e., whether any change-points may be detected in its somatic proportions. This fish has never been examined in this respect, and single-phase models, which are indeed easier to both compute and apply, are used in stock analyses. The following somatic relationships were analyzed in Atlantic bluefin tuna captured in the Mediterranean Sea between 1998 and 2010: “fork length–weight” regression, the von Bertalanffy growth equation, and “first dorsal spine cross section surface–fork length” regression. All of the examined relationships were found to be best modelled by multiple-phase regression equations, and all of them showed a change-point within the range of 101–110 cm fork length, which corresponds to 3–4 years of age. The present results, based on reproductive state-independent analyses, corroborate the disputed hypothesis that Atlantic bluefin tuna from the eastern stock in fact reproduce for the first time at this age

Epibiontic and endobiontic polychaetes of Geodia cydonium (Porifera, Demospongiae) from the Mediterranean Sea

Polychaete assemblages associated to the sponge Geodia cydonium were investigated at two sampling sites in the Mediterranean Sea: Porto Cesareo Basin (Apulia) and Marsala Lagoon (Sicily), both characterized by sheltered hydrodynamic conditions. Samples were seasonally performed during 1997, in order to compare the assemblages coming from the two localities studied, considering separately the internal and external tissues of the sponge, and with the aim of evaluating the influence of sponge size on polychaete colonization. The examined sponge is characterized by a peculiar stratification of its tissues: an external thick and hard layer, the cortex, and an internal softer one, the choanosome. Statistical analysis showed that this was the main factor controlling polychaete assemblage, with the internal tissue, less rich and diversified, appearing impoverished with respect to the external layer. A similarity in species composition was observed between sites, even though some differences were evidenced in the abundance of some species, mainly reflecting differences in local environmental conditions. Species richness and density increased with the increasing sponge size. Such a situation is particularly evident at Porto Cesareo, where sponges are covered by an algal layer which is particularly rich on the largest specimens, thus suggesting that most of the species of polychaetes were linked more to the neighbouring environment than to the sponge itself

Childhood Cancer Incidence in Georgia: Descriptive Epidemiology, Geographic Trends, and Disparities in Insurance Coverage, and Health Care Access

Background: Limited research has been conducted concerning childhood cancer (CC) incidence in Georgia, which is a leading cause of death for children in the US. The purpose of this study was to determine if county-level CC incidence rates differed by geography or race and if health care access disparities exist. Methods: Incidence data were obtained from the Georgia Comprehensive Cancer Registry for 2000-2011. Age-adjusted incidence rates per 100,000 were analyzed by sex, race, and county. Hotspots and coldspots of CC incidence were analyzed using the Getis-Ord GI* statistic. Health care access data for children under 19 were obtained using US Census Bureau’s Small Area Health Insurance Estimates for 2011. Georgia’s three children’s oncology group (COG) treatment facilities with 40-mile buffer zones were geographically overlaid with CC incidence rate maps and health insurance maps using Geographic Information Systems (GIS). Results: For leukemia and central nervous system cancers, incidence rates were significantly different between Whites [7.8, 95% confidence interval (CI) (7.4, 8.2)] and Blacks [5.2, 95% CI (4.8, 5.6)]. Statistical hotspots of CC were observed in north Georgia. A lower percentage of insurance coverage among children was observed in southeast GA. Approximately 25% of Georgia counties that were not within a COG buffer had a higher percentage of children who were uninsured (mean ± SD: 10.28% ±1.86%). Conclusion: Higher CC incidence rates and disparities in access to care were evident in north Georgia. Future research is needed in these geographies to investigate potential risk factors associated with CC incidence patterns and racial differences in Georgia

Protandric hermaphroditism in the bivalve Arca noae (Mollusca: Arcidae)

Following the histological analysis of Arca noae samples from the south-western Adriatic Sea, five hermaphroditic specimens were found out of 168 sexed individuals (3.0%). The hermaphrodite gonads showed the co-occurrence of male and female germ cells within the same acini, i.e. both spermatozoa in the lumen and oogonia lining its wall. Oogonia increased in size through winter, thus suggesting that the direction of sex change is from male to female. Both the biometrical analyses and theoretical considerations strongly suggest that A. noae is an obligate protandric species

Protandric hermaphroditism in the bivalve Arca noae (Mollusca: Arcidae)

Following the histological analysis of Arca noae samples from the south-western Adriatic Sea, five hermaphroditic specimens were found out of 168 sexed individuals (3.0%). The hermaphrodite gonads showed the co-occurrence of male and female germ cells within the same acini, i.e. both spermatozoa in the lumen and oogonia lining its wall. Oogonia increased in size through winter, thus suggesting that the direction of sex change is from male to female. Both the biometrical analyses and theoretical considerations strongly suggest that A. noae is an obligate protandric species