Historical legacies of river pollution reconstructed from fish scales

Abstract

Many rivers have been impacted by heavy metal pollution in the past but the long-term legacies on biodiversity are difficult to estimate. The River Ulla (NW Spain) was impacted by tailings from a copper mine during the 1970-1980s but absence of baseline values and lack of subsequent monitoring have prevented a full impact assessment. We used archived fish scales of Atlantic salmon to reconstruct levels of historical copper pollution and its effects on salmon fitness. Copper bioaccumulation significantly increased over baseline values during the operation of the mine, reaching sublethal levels for salmon survival. Juvenile growth and relative population abundance decreased during mining, but no such effects were observed in a neighbouring river unaffected by mining. Our results indicate that historical copper exposure has probably compromised the fitness of this Atlantic salmon population to the present day, and that fish scales are suitable biomarkers of past river pollution.

Prospects of fish scale and fin samples usage for nonlethal monitoring of metal contamination: a study on five fish species from the Danube River

“…Furthermore, metal accumulation in scales can be detected within days of exposure (Cooley and Klaverkamp, 2000). The main advantage of using scales as metal pollution indicators compared to other tissues is the possibility to use archived fish scales as predictors of past pollution (Cobelo-García et al, 2017;Morán et al, 2018). In addition, scales can be used as a sorption material for the extraction of various pollutants (heavy metal ions, dyes, antibiotics) from natural and wastewater (Shaikhiev et al, 2020).…”

Combined Use of Fatty Acid Profiles and Elemental Fingerprints to Trace the Geographic Origin of Live Baits for Sports Fishing: The Solitary Tube Worm (Diopatra neapolitana, Annelida, Onuphidae) as a Case Study

“…The biogenic carbonate-hard parts of marine species, such as shells, otoliths, plates, fish scales, and fish bones, incorporate and retain elements from the surrounding environment throughout their lifetimes [28,48,[60][61][62][63]. It is important to note that this study represents the first dataset reporting the EF of polychaete jaws.…”

Detecting Local Adaptation between North and South European Atlantic Salmon Populations

“…Wild populations of Atlantic salmon ( Salmo salar ) from the Iberian Peninsula suffered a drastic decrease in the last three decades of the 20th century, mainly due to anthropogenic actions such as pollution [ 1 ], the construction of physical barriers that reduced the habitat, and the increase in overfishing [ 2 , 3 ].…”