Effects of metals on sperm quality, fertilization and hatching rates, and embryo and larval survival of pejerrey fish (Odontesthes bonariensis)

Abstract

Some species of fish have been used as bioindicators of aquatic environmental pollution all over the world. Pejerrey (Odontesthes bonariensis) was selected for the current study due to its sensitivity to pollutants and because is one of the emblematic fish species that inhabits shallow lakes of the Pampa region (Argentina). Recently, in Chascomús lake were recorded concentrations of Cd, Cr, Cu and Zn with values above the Argentine National Guidelines for the Protection of the Aquatic life. Regarding this, the aim of the present study was to investigate the effects of environmental concentrations of these metals on the sperm quality, fertilization and hatching rates, and embryo and larval survival of pejerrey. Also, the same endpoints were analyzed with concentrations ten times higher to simulate a polluted worst-case scenario. The results showed that the presence of some metals in aquatic environments reduced pejerrey sperm motility (in~50%) and velocity (in~30%). These results were obtained using a computer assisted sperm analyzer enforcing the application of this analysis as a tool or bioindicator of aquatic pollution. In addition, fertilization rate was diminished (in~40%) for all treatments. Besides, the hatching rate, and embryo and larval survival were drastically affected being zero for the highest metal concentrations assessed. All together these results, showed that even lower metal concentrations can negatively affect different reproductive parameters of one of the most emblematic fish species of the Argentinean water bodies.

Impacts of heavy metals on early development, growth and reproduction of fish – A review

“… Species Dose Exposure period Alterations/ type of deformities References Cd Odontesthes bonariensis 0.25, 2.5 µg/l 10 days Reduced embryo and larval survivability [41] Oncorhynchus mykiss 2 µg/l 4 days Larval erythroblasts with MN, NB and BN [52] Danio rerio 60 ppb 7 dpf Decreased diameter of the saccule otolith, otoliths with numerous fiber between knobs [53] Cyprinus carpio 0.3, 0.06 mg/l 60 days Lowest survival and growth rate, malformation in the yolk sac, curvature in vertebral column, body shortening, and cardiac edema [49] Leuciscus idus 0.1 mg/l 21 dah Lowest survival, body length, body perimeter area, swim bladder [35] Oryzias latipes 0.18–19.8 μg/l 10 days Spinal deformities (kyphosis, lordosis and C-shaped larvae) [47] Silurus soldatovi 0.0001–30 mg/l 144 h Spinal curvature [34] Gambusia affinis 0.4 mg/l 30 days Spinal (kyphosis, lordosis and scoliosis) [46] Pagrus major 0–3.2 mg/l - Cardiac edema, blastodermal lesions and skeletal deformities (spinal curvature, degenerated and hooked tails, fins lesions) [32] Rhamdia quelen 0.0005–0.018 mg/l 21 dah Deformed spinal column [50] Oncorhynchus mykiss 0.05, 0.25, 0.50 & 2.50 μg/l 56 days Premature hatching, delayed hatching, lower larval growth [54] Danio rerio ...…”

“…Most of the literature reported reduced embryonic and larval survival, reduced and delayed hatching, stunted growth rate and morphological abnormalities such as skeletal deformities, vascular system abnormalities, reduction in pigmentation, eye anomalies etc. among different fish species exposed to lethal and sub-lethal doses of essential (Cu, Zn) and non-essential (Cd, Cr, Hg and Pb) heavy metals [32] , [38] , [40] , [41] , [42] . Cardiovascular endpoints such as hyper or hypo dystrophia, positioning abnormality, incomplete or abnormal heart looping, tubular heart, oedemata, megalocardia etc.…”

Effects of Anthropic Pollutants Identified in Pampas Lakes on the Development and Reproduction of Pejerrey Fish Odontesthes bonariensis

“…Consequently, all heavy metals listed above can damage the cell membranes of fish gametes ( Rurangwa et al, 1998 ). In the case of pejerrey, it was detected that sperm motility decreased in the presence of environmentally relevant concentrations of Cd, Cr in the activation solution, also affecting the fertility ( Gárriz and Miranda, 2020 ). Similar effects were reported in Rhamdia quelen , where increasing concentrations of Cd in the water were shown to reduce motility duration and in Cyprinus carpio with Cd, Cu and Pb ( Jezierska et al, 2009 ).…”

“…Apparently, Cd and Cu could alter the activity of chorion enzymes (choriolysin) and affect the movements at the muscular level necessary for hatching ( Calta, 2001 ). In pejerrey, a significant reduction in hatching rate and embryonic survival were observed when exposed to Cd, Cr, Cu and Zn at environmental concentrations ( Gárriz and Miranda, 2020 ). Fish larvae are also affected.…”

“…Pejerrey larvae showed to be more resistant to environmental Cr, however, their survival decreased significantly when exposed to Cu and Zn. The case of Cd exposure was peculiar, since a concentration 10 times higher than the environmental one had less lethal effects than the environmental concentration ( Gárriz and Miranda, 2020 ). It is possible that some pollutants, at determined concentrations, do not respond in a classic dose-response manner, but rather can show alternative patterns ( Calabrese, 2001 ).…”