Reduction in reproductive activity from degeneration of testicular follicles in Megapitaria squalida (Mollusca: Bivalvia) exposed to metal pollution in the Gulf of California.

Over a reproductive cycle, the prevalence and intensity of degeneration of testicular follicles in Megapitaria squalida collected from the mining port of Santa Rosalia (a highly metal-polluted area), and San Lucas (a less polluted site), Gulf of California, Mexico, were evaluated. At San Lucas, most individuals had a typical testicular structure, and degeneration of testicular follicles was present in 9.5 % of spawning organisms.

Human health risk assessment of metals and arsenic via consumption of commercial bivalves in the Gulf of California, Mexico.

Although various studies have reported the bioaccumulation of metals in bivalves of commercial interest from the Gulf of California (GC), the risk associated with their consumption remains poorly understood. In this study, our own and bibliographic concentrations of 14 elements in 16 species of bivalves from 23 locations were used to investigate (1) the species-specific and regional accumulation of metals and arsenic in bivalves, (2) the human health risks by age and sex, and (3) the maximum allowable consumption rates (CRlim). The assessments were done according to the US Environmental Protection Agency guidelines.

Is There a Risk to Humans from Consuming Octopus Species from Sites with High Environmental Levels of Metals?

Although octopuses are in high-demand globally and can bioaccumulate high concentrations of metals, the risk associated to its consumption is poorly understood. We compiled literature data from eight locations in Europe, North America and Northern Africa with different environmental levels of metals to evaluate: (1) the risk to human health through consumption of muscle tissues and digestive glands of Octopus hubbsorum, O. vulgaris and Eledone cirrhosa, and (2) the maximum allowable consumption rates (CR).

Histopathological Alterations in the Gonad of Megapitaria squalida (Mollusca: Bivalvia) Inhabiting a Heavy Metals Polluted Environment.

The gonadal health status of the chocolate clam Megapitaria squalida collected from the Santa Rosalía mining port and San Lucas beach (reference site), Gulf of California, Mexico, was assessed through histological analysis of the reproductive tissue, from which the histopathological alteration index (HAI) was determined. In addition, copper and iron accumulation in tissue was revealed using histochemical techniques. Our results showed a large presence of copper (30%) and iron (45%) only in the gonad tissue of clams from Santa Rosalía, in which histopathological alterations observed were inflammatory responses, degenerative-progressive processes, cell death, and response to infectious agents.

Life histories predict genetic diversity and population structure within three species of octopus targeted by small-scale fisheries in Northwest Mexico.

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery.

Bioaccumulation and biomagnification of potentially toxic elements in the octopus Octopus hubbsorum from the Gulf of California.

The concentrations of 21 potentially toxic elements (PTEs) were determined in the tissues of Octopus hubbsorum from three locations along the Gulf of California coast: two near Santa Rosalia (SR), a site with historical metal contamination, and one in La Paz Bay, a reference site. Concentrations of Cd, Co, Cr, Mn, Ni, Pb, and Zn in octopus from the two SR sites were higher than those from the reference site, reflecting the higher sediment concentrations at the mining-impacted locations. The highest bioaccumulation and biomagnification of elements was found in digestive gland and branchial hearts, while the lowest was observed in the mantle, where the mean concentration of PTEs did not exceed international standards for human consumption of octopus.

The complete mitochondrial genome of Octopus bimaculatus Verrill, 1883 from the Gulf of California.

The complete mitochondrial genome of Octopus bimaculatus is 16 085 bp in length and includes 13 protein-codes genes, 2 ribosomal RNA genes, 22 transfers RNA genes, and a control region. The composition of genome is A (40.9%), T (34.

[Reproductive biology of the golden snapper Lutjanus inermis (Perciformes: Lutjanidae) in the central Mexican Pacific].

Reproductive aspects and information on the effect of fishery activities over this species stock are scarce, despite the imperative need of effective protection and resource management programs. To support the possible establishment of closed seasons and catch levels for the area, our study aimed to evaluate the spawning season of the Golden snapper (Lutjanus inermis). For this, fish caught by artisanal fisheries in the Navidad, Tenacatita and Chamela bays (Jalisco, Mexico) were sampled monthly from 1999-2008, and analyzed sex ratios, spawning season and size at first maturity.