Effect of ultraviolet radiation (UVR) on the life stages of fish

Abstract

Current levels of Ultraviolet Radiation (UVR) represent a significant threat to many fish species. The first studies on the effects of UVR on organisms were performed on fish at the beginning of the twentieth century, and the topic has been progressing continuously until the present. Here, we review the reported harmful effects of ultraviolet B (UVB) and A (UVA) radiations in fish at different lifecycle stages, including embryo, larvae, juveniles and adults. The most evident negative effects during the early development stages are an increase in mortality and incidence in developmental malformations, with the skin and gills the most affected tissues in larvae. Growth reduction, a loss in body condition, and behavioral, physiological and metabolic changes in juveniles/adults occur under short- or long-term UVB exposure. The skin in juveniles/adults undergoes profound morphological and functional changes, even after acute exposure to UVR. Impairment of molecular and cellular processes was evidenced in all development stages by increasing the levels of DNA damage, apoptosis and changing tissues’ antioxidant status. The different photo-protective mechanisms to cope with excessive UVR exposure are also revised. Currently, stratospheric ozone dynamics and climate change interact strongly, enhancing the potential exposure of fish to UVR under water. Due to these environmental changes, fish are exposed to new and complex interactions between UVR and environmental stressors, which potentially affects fish growth and survival. Understanding the ability of fish to cope and adapt to these environmental changes will be essential to evaluate the potential impact in fisheries and mitigate ecological problems.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…9 ). Negative effects range from developmental abnormalities, to decreases in growth and body condition, to lesions in skin, eyes, as well as in many other organs, and even death [ 263 ]. Often, the more transparent, younger life-history stages are vulnerable to UV-induced damage, in particular because they typically inhabit shallow, warmer surface waters to increase developmental rates.…”

“…Often, the more transparent, younger life-history stages are vulnerable to UV-induced damage, in particular because they typically inhabit shallow, warmer surface waters to increase developmental rates. The skin and gills are the most highly exposed and most likely sites of damage by UV-B radiation, although immune suppression, visual impairment, and other damage is commonly reported in both natural populations and hatchery-raised fish [ 263 ]. The corresponding reductions in fish survival, growth, and reproduction have as yet unquantified implications for the yield of commercial and recreational fisheries that provide critical supplies of food to much of the world’s population (SDG 2.4).…”

“…RBA, respiratory burst activity; NCC, non-specific cytotoxic cells. From Alves and Agusti 2020 [ 263 ] …”

Epidermal Club Cells in Fishes: A Case for Ecoimmunological Analysis

“…In previous studies, cortisol has been shown to modulate the immune response [ 146 , 171 , 172 , 173 ] and decrease club cell density [ 146 ]. Cortisol levels were also increased upon exposure to UV rays [ 19 , 20 ], and UV rays can affect other aspects of fish’s immune systems [ 174 ]. Clearly, further studies are needed to establish the mechanistic links and signaling pathways.…”

From Sea to Skin: Is There a Future for Natural Photoprotectants?

“…UVR are not only dangerous for photosynthetic organisms but they can cause damage to a wide range of living organisms, from bacteria to higher vertebrates, and their effects can change depending on other environmental conditions [ 35 ]. For instance, UVR negatively affects the viability and development of invertebrates and fish, whose early developmental stages are generally more sensitive [ 36 , 37 ]. Indeed, CPDs formation in sea urchin embryos and larvae inhibits their development, decreasing population survival and fitness [ 38 ].…”