Differential tolerance of native and nonnative fish exposed to ultraviolet radiation and fluoranthene in Lake Tahoe (California/Nevada), USA

Abstract

Within Lake Tahoe (CA/NV), USA, multiple environmental stressors are present that can affect both native and nonnative fish species. Stressors include natural ultraviolet radiation (UVR) and polycyclic aromatic hydrocarbons (PAHs). Many PAHs, such as fluoranthene (FLU) are phototoxic to aquatic organisms in the presence of UVR. Decreasing levels of UVR due to eutrophication and increasing levels of PAHs due to recreational activities may combine to affect the relative ability of native versus nonnative fish species to survive in the lake. The objective of the present study was to examine the differential effects of exposure to different levels of UVR and phototoxic FLU in native and nonnative fish species. Responses to these changes in the native Lahontan redside minnow (Richardsonius egregius) and the nonnative warm-water bluegill sunfish (Lepomis macrochirus) were compared during toxicity tests, which were conducted in controlled outdoor exposures. Physiological defenses were also investigated in an attempt to elucidate ways each species may tolerate UVR and UVR + FLU exposures. It was determined that the native redside minnow is more tolerant to UVR and UVR + FLU exposure when compared to the nonnative bluegill. In addition, a natural UVR coping mechanism, increased pigmentation, is exhibited to a greater extent in the native redside. The present study will help determine the potential for a future successful invasion of the bluegill and similar species in Lake Tahoe and other oligotrophic, montane lakes that are susceptible to habitat alteration, nutrient inputs, and recreational activity.

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

“…Microscopic examination of native Lahontan redside minnow (Richardsonius egregius) and non-native warm-water bluegill sunfish skin exposed to UVR revealed that the native species is more adapted to high UV conditions that are characteristic of the environment of the near shore Lake Tahoe (Gevertz and Oris 2014). The skin from bluegill sunfish exhibited greater damage in both epidermis (more irregular and thinner) and dermis (formation of extracellular space) and potential DNA damage and impairment of cellular respiratory processes (Gevertz and Oris 2014;Gevertz et al 2012). In sole (Solea solea), larval skin is slightly pigmented, and five days of exposure to UVB (2.15 kJ m -2 d -1 ) resulted in the appearance of the characteristic sunburn because of damaged cells and a reduction in the size of the mucous producing cells.…”

“…In the liver, whitefish larvae exposed to UVB and 10 or 32 mg L -1 retene showed hepatocytes containing necrotic nuclei (Häkkinen et al 2003). Gevertz et al (2012) demonstrated that the nonnative bluegill sunfish is more susceptible than the Lake Tahoe native Lahontan redside minnow to the harmful effects of combined exposure to UVB radiation and fluoranthene (FLU). When exposed only to UVB, the native redside minnow displayed more tolerance (LD 50 , 28.0 W cm -2 h -1 UVB) to the radiation than the non-native bluegill sunfish (LD 50 , 4.6 W cm -2 h -1 UVB).…”

Acute photo‐induced toxicity and toxicokinetics of single compounds and mixtures of polycyclic aromatic hydrocarbons in zebrafish

“…Zebrafish are a model organism for testing the effects of toxicants in the aquatic environment . Because larval fish are translucent and respire via diffusion of oxygen through the skin, and because the lipids of their cell membranes have a high potential for accumulation of PAHs, direct UV exposure makes these organisms one of the most sensitive to photo‐induced toxicity . Because photo‐induced toxicity is related to the internal PAH dose and intensity of UV radiation, toxicokinetics and differences in PAH body burden can be useful in assessing risk .…”

Adverse Effects of Ultraviolet Radiation on Growth, Behavior, Skin Condition, Physiology, and Immune Function in Gilthead Seabream (Sparus aurata)

“…At the end of the experiment, the percentage of fish showing lesions on their skin was 73 and 35% in the UVB-M (6.1 kJ m −2 d −1 ; absolute UVB doses for the experimental period of 261 kJ m −2 ) and UVB-L (2.4 kJ m −2 d −1 ; absolute UVB doses for the experimental period of 103 kJ m −2 ) treatments, respectively. Evidence of sunburn and skin lesions after UVB overexposure has been reported during all fish development stages (Gevertz et al, 2012;Sucré et al, 2012). For example, Fabacher and Little (1995) studied the effect of UVB exposure over 7 days (UVB dose, 34.2 kJ m −2 d −1 ; absolute UVB doses after 7 days of exposure, 239.4 kJ m −2 ), producing sunburn and skin lesions in different fish species.…”