A ten-year monitoring of essential and non-essential elements in the dolphinfish Coryphaena hippurus from the southern Gulf of California.

The concentrations of As, Cd, Cu, Pb and Zn were measured in muscle tissue of Coryphaena hippurus captured in the southern Gulf of California to determine inter-annual variations and their relation with environmental parameters for the period 2006-2015; additionally, health risk to consumers was assessed according to levels of studied elements and rate of fish consumption in northwest Mexico. During 2014 and 2015 the levels of As, Cd, Cu, and Zn were significantly lower than the rest of the years; in the case of As, it was also significantly lower in 2010. Oceanic Niño Index was negatively correlated with Zn concentrations in fish, while sea surface temperature was negatively correlated with Zn, Pb and Cd concentrations in dolphinfish. The simultaneous occurrence of the analyzed elements in muscle of dolphinfish indicated that health effects on consumers are not likely to occur; nevertheless, fishermen with elevated fish consumption might be at risk.

First insight into plastics ingestion by fish in the Gulf of California, Mexico.

Plastic particle occurrence in the digestive tracts of fishes from a tropical estuarine system in the Gulf of California was investigated. A total of 1095 fish were analysed, representing 15 species. In total 1384 particles of plastic debris were recovered from the gastrointestinal tracts of 552 specimens belonging to 13 species, and all consisted of threads, the majority of which were small microplastics (0.23 to 1.89), followed by large microplastics (2.07 to 4.49), and few mesoplastics (5.4 to 19.86). Plastic particles were identified using ATR-FTIR spectroscopy. The mean frequency of occurrence of plastics in the gastrointestinal tracts of fishes from this system was 50.5%, which is higher than frequencies reported in similar systems in other areas. The polymers identified by ATR-FTIR were polyamide (51.2%), polyethylene (36.6%), polypropylene (7.3%), and polyacrylic (4.9%). These results show the first evidence of plastic contamination for estuarine biota in the Gulf of California.

Mercury Levels in Fish for Human Consumption from the Southeast Gulf of California: Tissue Distribution and Health Risk Assessment.

We assessed human health risk due to mercury (Hg) concentrations in fish from three coastal lagoons (Urías, Huizache, and Teacapán) in the SE Gulf of California. We also determined Hg distribution in muscle and liver of analyzed ichthyofauna and compared the results among studied areas according to tissue, season, and lagoon system by using multivariate analyses. Levels of Hg in most of the analyzed fish followed the sequence liver > muscle. The highest Hg levels in muscle (2.80 µg g-1 dw) and liver (9.51 µg g-1 dw) were measured in Cynoscion reticulatus and Pomadasys macracanthus, respectively, although according to the multivariate analyses, statistical differences of Hg concentrations were not found according to the season and the tissue but were found according to the system. It seems that the higher concentrations were associated with areas where the hydrological regime is lower. With respect to health risk assessment, the highest hazard quotients were estimated for Cynoscion reticulatus (0.45) and Stellifer furthii (0.29) from Urías and Pomadasys macracanthus (0.35) from Huizache. None of the studied fish represent a risk for consumers in terms of Hg levels in the edible portion.