No abstract

Aiming to determine an appropriate protocol for short-term storage of the sperm of San Pedro Mártir trout, Oncorhynchus mykiss nelsoni, wild fish previously matured in captivity were anesthetized and the semen, obtained by abdominal pressure, was suspended in Erdhal and Graham extender at 1:3, 1:6 and 1:9 dilution ratios and kept at 4° C for 9 days with an undiluted sample as control. The percentages of sperm motility and membrane integrity were assessed daily. The results indicated that sperm suspended at a dilution of 1:9 can be stored at 4° C with ≥ 80% motility and ≥ 65% membrane integrity for 7 and 6 days respectively. In addition, the results show that membrane integrity decreased more rapidly than motility, which suggests that it may be used as an early indicator of sperm damage during short-term cold storage. The results obtained are important to support future conservation programs of this trout.

The aim of this work was to survey the discharges of dissolved and particulate Cd, Cu, Fe, Mn, Pb and Zn of the eight main rivers of Sinaloa State to the Mexican coastal environment. Zn was the most abundant dissolved metal and Fe was the most abundant particulate (8.02-16.90 and 51.8-1,140.3 μg/L, respectively). Only particulate Mn had significantly (p = 0.028) higher values in summer-fall (rainy season), whereas the significantly (p = 0.036) higher values of dissolved Zn were observed in winter and spring. The highest annual total discharges to Sinaloa coastal waters were those of the rivers San Lorenzo and Piaxtla (>2 × 10(3) m.t.) and the lowest those of rivers Baluarte and El Fuerte (349 and 119 m.t., respectively). Pb concentrations may become of concern, because they are higher than the value recommended for the welfare of aquatic communities of natural waters.

No abstract

To assess if they were within the safety limits for human consumption, the Cd, Cu, Pb, and Zn contents of fish muscles, bought from separate stalls of the fish markets of nine cities of NW Mexico, were determined by atomic absorption spectrophotometry. Considering all fish and markets, the mean contents were Zn: 23.23 ± 5.83, Cu: 1.72 ± 0.63, Cd: 0.27 ± 0.07, and Pb: 0.09 ± 0.04 µg/g (dry weight). Cu, Zn, and Pb did not reach levels of concern for human consumption, but the high Cd values determined in Mazatlán (Mugil cephalus: 0.48 ± 0.15; Diapterus spp.: 0.57 ± 0.33; Lutjanus spp.: 0.72 ± 0.12; small shark: 0.87 ± 0.19 µg/g dry weight) indicate that this was the only metal of concern for human health because the daily individual consumption of fish muscle to reach the PTDI would be within 0.27 and 0.41 kg.