RESUMEN
The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in five commercially valuable squid species from different geographical origins (Atlantic, Indic and Pacific Oceans). Out of the 18 quantified PAHs (the 16 PAHs considered by US EPA as priority pollutants, dibenzo(a,l)pyrene and benzo(j)fluoranthene) only dibenz(a,h)anthracene was not detected. The total concentrations of PAHs varied by a factor of more than 100-fold, from 0.22 (Loligo gahi) to 60.9 µg/kg ww (Loligo reynaudii). Intra- and inter-specific variability of PAH levels was statistically assessed. Nine carcinogenic (probable/possible) PAHs accounted for 1% (L. reynaudii) to 26% (Loligo opalescens) of the total PAHs content being the main contributors naphthalene (in Loligo duvaucelii, L. reynaudii and Loligo vulgaris species), chrysene (in L. opalescens) and indeno(1,2,3-cd)pyrene (in L. gahi). PAHs source analysis indicated that four of the five zones of capture of the different squid species are significantly affected by both petrogenic and pyrolytic sources. Assessment of the target carcinogenic risks, established by the US EPA, suggested that L. gahi (Atlantic Ocean) and L. opalescens (from Pacific Ocean) may pose additional risks for consumers, if not eaten in moderation, derived from benzo(a)pyrene ingestion.
Asunto(s)
Carcinógenos Ambientales/análisis , Contaminación de Alimentos , Loligo/química , Mutágenos/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Mariscos/análisis , Contaminantes Químicos del Agua/análisis , Adulto , Animales , Océano Atlántico , Carcinógenos Ambientales/toxicidad , Dieta/efectos adversos , Monitoreo del Ambiente , Enfermedades Transmitidas por los Alimentos/epidemiología , Enfermedades Transmitidas por los Alimentos/etiología , Salud Global , Humanos , Océano Índico , Loligo/crecimiento & desarrollo , Mutágenos/toxicidad , Neoplasias/inducido químicamente , Neoplasias/epidemiología , Neoplasias/etiología , Océano Pacífico , Hidrocarburos Policíclicos Aromáticos/toxicidad , Portugal/epidemiología , Riesgo , Mariscos/efectos adversos , Contaminantes Químicos del Agua/toxicidadRESUMEN
Newly hatched paralarvae ("hatchlings") or late-stage embryos of Loligo opalescens were dissected and pieces of tissue removed for immunostaining as flat whole mounts. The general layout of the peripheral nervous system in the mantle and gills was investigated using antisera for tubulin and FMRFamide. Primary sensory neurons are densely distributed in the outer mantle epidermis and show strong FMRFamide immunoreactivity. Their axons form a plexus in the underlying dermis, but do not appear to innervate the chromatophore muscles, which are well visualized with anti-tubulin. Some cross the muscle layer and enter the stellate ganglia via the stellar nerves. The stellate ganglion neuropil contains a rich FMRFamide-immunoreactive mass of axons. It is suggested that these axons originate in large part from sensory neurons in the skin and that the known modulatory effects of FMRFamide-related peptides on motor output of the stellate ganglion may be a reflection of this sensory input in normal life. FMRFamide-immunoreactive primary sensory neurons are also abundant in the gills, but unlike those in the mantle, these cells lack cilia or other external projections. Anti-tubulin staining reveals a network of interstitial cells in the mantle dermis. Such networks may have been mistaken for nerve nets in older accounts. Additional results with Octopus vulgaris hatchlings and immunostaining for serotonin (5HT), small cardioactive peptide (SCP), and gonadotropin releasing hormone (GnRH) are briefly reported.
Asunto(s)
Loligo/citología , Loligo/embriología , Nervios Periféricos/citología , Animales , FMRFamida/metabolismo , Inmunohistoquímica , Larva/metabolismo , Loligo/crecimiento & desarrollo , Nervios Periféricos/química , Nervios Periféricos/ultraestructura , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismoRESUMEN
A new approach is presented here to better take into account inter-individual growth variability in age-structured models used for stock assessment. Cohort analysis requires knowledge of the age structure of the catch, generally derived from an age-length key and length-structure information. Age distribution at length is estimated by applying conditional quantile regression to a data set of lengths and ages estimated from calcareous parts. A "stochastic" age-length key that describes the probability of age-at-length is applied to the English Channel squid Loligo forbesi. Age distribution at length from quantile regression proved to be considerably less biased than that resulting from both polymodal decomposition (PD) and two separate slicing methods. Both catch-at-age and stock size were underestimated using classical methods. Estimations of fishing mortalities from classical methods were higher causing underestimation in yield simulations. Quantile regression offers a more complete statistical analysis of the stochastic relationships among random variables than mean regression and PD.