The red abalone, Haliotis rufescens (Swanson 1822), is an important species for commercial aquaculture in Mexico, with annual production levels around 68 t. Not surprisingly, there is great interest in increasing production and its cultivation success. In order to have a better understanding of the genes involved in the sexual differentiation, this study analyzed the early differential expression of eight sex-related genes (VCP 2.2, VERL, VTGI, DMRT1, FP, LYS, SARIP, TEKT A1) by RT-qPCR in abalones from 5 to 45 mm of shell length. Sex identification was evaluated using VERL and LYS genes expression levels. These genes differentiated females and males from 16 mm of shell length and above. All eight sex-specific genes showed expression in all organisms. However, their level was higher in the sex group to which they correspond. In contrast, differential expression levels occurred in individuals with a shell length of 26–35 mm and 36–45 mm. These results suggest that sex gene expression is not entirely sex specific, and sexual differentiation in red abalone occurs between 16 and 25 mm of shell length. More studies are needed to determine the function of these genes in the sex that they are not associated with.

The Gulf of Mexico is an important crude oil reserve worldwide, and the oyster Crassostrea virginica is an excellent candidate to study the oil spill impacts on marine invertebrates. In this work, the concentrations of polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs) from eight productive oyster areas in the Gulf of Mexico were measured on sediment, water, and tissues from C. virginica. In water, the highest AHs concentration was detected in Tamiahua (0.50 ng/mL), while for PAHs, the highest concentration was > 0.10 ng/mL in Tampamachoco. In sediment, Tamiahua and Tampamachoco lagoons had the highest AHs concentrations with values near 2.5 μg/g dry weight. Considering the PAHs, Tamiahua, Carmen, and Tampamachoco lagoons registered the highest levels, with values > 60 ng/g dry weight. In tissues from C. virginica, La Pesca, Cármen and Mecoacán presented the highest PAHs concentrations with values between 0.20 and 0.25 μg/g dry weight. Furthermore, from the molecular analysis of genes related with different phases of the xenobiotic detoxification process such as hypoxia inducible factor (hif-1a), cytochrome P450 10 (cyp10), flavin mono-oxygenase (fmo), glutathione S-transferase (gstΩ1), multidrug resistant protein (mdrd1), catalase (cat), among others, the differences between lagoons were significant (P< 0.05) and generally with Las Enramadas showing the highest expression levels. From genes evaluated in this study, hif-1a, cyp10, fmo, mdrd1 and cat presented the highest expression differentials between lagoons. The above allowed us to validate the utility of molecular markers in the assessment of the hydrocarbons effect on oyster under the conditions from the Southern Gulf of Mexico.

Bile acids were added to the Penaeus vannamei diet to evaluate their effect on the growth, survival, and immune response. Dietary doses of 750, 2250, and 3750 ppm, including control treatment without adding bile acids, were evaluated over 28 days. The results indicated no significant difference in growth, total hemocyte count, phenol oxidase enzyme concentration, and superoxide anion between treatments (p > 0.05). However, bile acid supplementation induced a high survival and higher plasma protein production at 2250 ppm treatment (p < 0.05). Likewise, including bile acids in the diet at a rate of 2250 ppm promoted a higher content of lipids in the hepatopancreatic tubules. Based on the above, it is concluded that supplementing the commercial diet of Penaeus vannamei with bile acids at a concentration of 2250 ppm promotes high survival and plasma protein production and improves the lipid content in the hepatopancreatic tubules.

Batoids (rays, skates, and relatives) are among the most threatened cartilaginous fishes globally, yet the molecular diversity of Peruvian taxa remains poorly evaluated. Furthermore, regional barcode sequences for high-conservation-priority taxa, such as sawfish, manta, and devil rays, are often restricted to private records, hindering essential phylogeographic and population structure assessments. To bridge this gap, we developed BATOseq-PE, the first public genetic reference library for Peruvian marine batoids, covering 14 species sequenced in vitro from local specimens, complemented by a novel in silico assembled mitogenome for Notoraja martinezi . This open-access repository contributes 73 novel COI barcodes, providing robust taxonomic resolution across 15 molecular operational taxonomic units (MOTUs) and Barcode Index Numbers (BINs). Notably, we provide the first Peruvian public records for high-priority species such as Mobula munkiana , Mobula thurstoni , Myliobatis peruviana , Rostroraja velezi , and the first global public barcodes for N . martinezi and Zapteryx xyster . By coupling BATOseq-PE with global datasets, we conducted the first multi-taxa screening for delimitation and phylogeographic assessments on Peruvian rays, revealing a cryptic lineage within R. velezi and genetic connectivity patterns suggesting female philopatry in Mobula mobular . Finally, by integrating nucleotide diversity into a Genetic Diversity Risk Indicator (GDRI) alongside ecological and fishery data, we identified an alarming trend where heavy fishing pressure overlaps with extinction risk and depleted genetic diversity, allowing us to suggest data-driven, tailored management strategies. BATOseq-PE represents a valuable resource to accelerate taxonomic and population assessments, ultimately fostering ray conservation through the integration of genetic frameworks into fishery management.