Evaluation of acute copper toxicity during early life stages of gilthead seabream, Sparus aurata

Abstract

In this study, the effects of exposure to copper (mortality and morphological alterations) on the early life stages of the gilthead seabream, Sparus aurata, were examined. Eggs/embryos and larvae were exposed to nominal concentrations of copper ranging from 0.0001 to 10 mg/L Cu (II) in the tests with eggs/embryos and 0.025 to 0.5 mg/L Cu (II) in the test with larvae. Duration of the assays was 48 hours for embryos and 96 hours for larvae. A high percentage of mortality was observed in embryos exposed to 0.1 mg/L (97.2%) and in larvae exposed to 0.5 mg/L (100%). The embryos proved the most sensitive to copper for the same duration of exposure. The acute toxicity expressed as LC(50) 48 hours was 0.054 (0.048-0.058) mg/L for embryos and 0.261 (0.182- 0.375) mg/L for larvae. Morphological alterations or abnormalities in embryos included irregular shapes of chorion, opacity and vitellus retraction/degeneration. In larvae we observed poor capacity to swim, trembling, myoskeletal defects, opacity and exophthalmia. Histopathological alterations are observed in S. aurata larvae. Mucous cells of the digestive tissue present a severe alteration with an increment of exudates. A great cellular disorganization in the renal tissue is observed. Results from this work indicate the high sensitivity of early life stages of Sparus aurata to copper (II) and the persistence of sublethal effects.

Toxicity of short‐term copper exposure to early life stages of red sea bream, Pagrus major

“…In euryhaline killifish Fundulus heteroclitus (96-h LC50: 18 mg Cu/L in freshwater and 294 mg Cu/L in 35% seawater) and topsmelt Atherinops affinis (168-h LC50: 44, 72, 134, and 205 mg Cu/L in 10, 17, 25, and 34% waters, respectively), larvae also became less sensitive to Cu as salinity increased [22,23]. In the present study, the 96-h LC50 for red sea bream larvae was 0.13 mg Cu/L, which falls within the reported values for other marine fish larvae [10,[19][20][21]. Copper toxicity in fish at ELS is substantially affected by salinity.…”

“…Under similar experimental conditions, the 96-h LC50 values of Cu for a large majority of the reported freshwater fish larvae varied remarkably from 3.4 mg Cu/L for Chinook salmon to 690 mg Cu/L for blue tilapia Oreochromis aureus [17,18]. In the few tested marine fish larvae, these values ranged from 68 mg Cu/L for anchovy Engraulis japonicus to 1,800 mg Cu/L for sea bass Lates calcarifer [10,[19][20][21]. These results suggest that marine fish larvae might tolerate Cu exposure more than their freshwater counterparts.…”

“…On the other hand, some studies found that chorions became more permeable to toxicants during embryogenesis, thereby increasing the sensitivity of the developing embryos to toxicants [7,10,31]. Herrmann [32] suggested that the early embryonic stage in which the chorions had not yet hardened was particularly susceptible to waterborne contaminants.…”

“…Copper exposure to fish at ELS could cause various developmental abnormalities such as morphological deformity, low hatching success and survival, a delay in hatching, and a reduction in growth, all of which would adversely affect fish recruitment and population dynamics [5][6][7]. Therefore, fish ELS are often used as a biological endpoint in toxicity tests for risk assessment on the aquatic environment, aquaculture, and fishery resources [6,10].…”

The impact and control of biofouling in marine aquaculture: a review

“…Unlike tributyltin and nickel, copperbased coatings remain in use despite their negative impacts on developing vertebrates and invertebrates (Oliva et al 2007), and their ability to concentrate in shellfish tissues (Changsheng et al 1990). The use of copper on equipment is discussed in detail below as this is the most common method of deterring the settlement and growth of fouling organisms on equipment used in finfish aquaculture.…”