Abstract
The increasing human presence in the Arctic shelf seas, with the expansion of oil and gas industries and maritime shipping, poses a risk for Arctic marine organisms such as the key species polar cod (Boreogadus saida). The impact of dietary crude oil on growth and metabolism of polar cod was investigated in the early spring (March–April) when individuals are expected to be in a vulnerable physiological state with poor energy stores. Adult polar cod were exposed dietarily to three doses of Kobbe crude oil during an eight weeks period and followed by two weeks of depuration. Significant dose-responses in exposure biomarkers (hepatic ethoxyresorufine-O-deethylase [EROD] activity and 1-OH phenanthrene metabolites in bile) indicated that polycyclic aromatic hydrocarbons (PAHs) were bioavailable. Condition indices (i.e. Fulton's condition factor, hepatosomatic index), growth, whole body respiration, and total lipid content in the liver were monitored over the course of the experiment. The majority of females were immature, while a few had spawned during the season and showed low hepatic lipid content during the experiment. In contrast, males were all, except for one immature individual, in a post-spawning stage and had larger hepatic energy stores than females. Most specimens, independent of sex, showed a loss in weight, that was exacerbated by exposure to crude oil and low hepatic liver lipids. Furthermore, females exposed to crude oil showed a significant elevation of oxygen consumption compared to controls, although not dose-dependent. This study highlights the importance of the energy status of individuals for their response to a crude oil exposure.
Highlights
Climate variability and global warming have changed and will continue to change the Arctic, most notably seen in the abrupt decline in Arctic sea ice extent and thickness (Barber et al, 2015)
The levels of polycyclic aromatic hydrocarbons (PAHs) measured in the feed were significantly correlated to the nominal crude oil doses (R2 = 0.97, p < 0.001), indicating that the crude oil was homogenously mixed in the feed
The present study revealed a negative impact of crude oil exposure on growth performance on adult polar cod with low condition in the early spring
Summary
Climate variability and global warming have changed and will continue to change the Arctic, most notably seen in the abrupt decline in Arctic sea ice extent and thickness (Barber et al, 2015) In parallel with these changes, anthropogenic activities including oil and gas exploration, maritime shipping, and tourism are all predicted to increase (Smith and Stephenson, 2013), posing a risk to arctic marine organisms. Gravato and Guilhermino, 2009; Kerambrun et al, 2012; Claireaux et al, 2013; Sandrini-Neto et al, 2016) and metabolism (Davoodi and Claireaux, 2007; Christiansen et al, 2010; Klinger et al, 2015) in fish The mechanisms behind these effects can be multiple, including increased energy costs from detoxification metabolism
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