389
trophic changes, and various physiologically based sub-lethal effects on oil-exposed
fishes and especially consider research undertaken following the Deepwater Horizon
and Ixtoc 1 spills in the Gulf of Mexico.
Keywords PAHs · Oil-exposed fish · Sub-lethal effects · Population fitness · LC 50
24.1 Introduction
The 2010 Deepwater Horizon and the 1979–1980 Ixtoc 1 oil spills were the two
largest anthropogenically induced oil releases to occur in the Gulf of Mexico (GoM)
and the second and third largest global oil spills, respectively, in contaminant volume released (the largest being the Persian Gulf War). Both the DWH and Ixtoc 1
incidents were subsurface blowouts creating surface slicks, water column oil emulsions, and benthic oil deposits, all of which resulted in marine life encounters with
oil. Spawning for most marine fishes in the GoM occurs during spring and summer
months (Chancellor 2015; Chancellor et al. 2020), thus overlapping with both spills
in the GoM. Yet, unlike the 1989 Exxon Valdez oil spill and other nearshore tanker
accidents, in which acute impacts on wildlife were highly visible, the offshore, subsurface nature of both the DWH and Ixtoc 1 on fish and fisheries was less obvious
and may have taken years to fully express in terms of their outcomes.
Crude oil and its derived petroleum compounds are comprised of ~97% hydrocarbons with the remaining 3% made up of minor elements including nitrogen,
sulfur, and oxygen (NRC 2003). Polycyclic aromatic hydrocarbons (PAHs) comprise a small compositional percentage (0.2–7%) of crude oil, yet they are considered the most toxic components primarily due to their metabolites (James and
Kleinow 1994; NRC 2003). The toxic potential of PAHs in fish exposed during oil
spills have been well documented and reviewed extensively in the literature (e.g.,
Reynaud and Deschaux 2006; Beyer et al. 2016). Following DWH, a number of
studies focusing on sub-lethal impacts examined a range of adverse acute and
chronic effects, including skin lesions, cardiotoxicity, liver abnormalities, respiration changes, reproductive irregularities, histopathological changes, and also mortality (Murawski et al. 2014; Incardona et al. 2014; Brown-Peterson et al. 2015a, b;
Klinger et al. 2015; Bentivegna et al. 2015; Hedgpeth and Griffitt 2016; Esbaugh
et al. 2016; Olson et al. 2016; Grosell et al. 2020; Portnoy et al. 2020).
Toxicity testing has, in the past, concentrated on laboratory exposures using relatively high-dose concentrations (to elicit effects) and with “model” organisms, not
usually found in actual spills. Consequently, using laboratory-based toxicity experiments can be problematic when making inferences about potential impacts in wild fish
at environmentally relevant pollutant concentrations. Nevertheless, consistent sublethal effects have been observed between laboratory studies and field studies. This
chapter explores sub-lethal effects observed primarily from sampling of naturally
occurring fish populations in the GoM following two major oil spills, the Deepwater
Horizon and the Ixtoc 1. In the case of the Ixtoc 1 spill, few fishes (perhaps a few long24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…
trophic changes, and various physiologically based sub-lethal effects on oil-exposed
fishes and especially consider research undertaken following the Deepwater Horizon
and Ixtoc 1 spills in the Gulf of Mexico.
Keywords PAHs · Oil-exposed fish · Sub-lethal effects · Population fitness · LC 50
24.1 Introduction
The 2010 Deepwater Horizon and the 1979–1980 Ixtoc 1 oil spills were the two
largest anthropogenically induced oil releases to occur in the Gulf of Mexico (GoM)
and the second and third largest global oil spills, respectively, in contaminant volume released (the largest being the Persian Gulf War). Both the DWH and Ixtoc 1
incidents were subsurface blowouts creating surface slicks, water column oil emulsions, and benthic oil deposits, all of which resulted in marine life encounters with
oil. Spawning for most marine fishes in the GoM occurs during spring and summer
months (Chancellor 2015; Chancellor et al. 2020), thus overlapping with both spills
in the GoM. Yet, unlike the 1989 Exxon Valdez oil spill and other nearshore tanker
accidents, in which acute impacts on wildlife were highly visible, the offshore, subsurface nature of both the DWH and Ixtoc 1 on fish and fisheries was less obvious
and may have taken years to fully express in terms of their outcomes.
Crude oil and its derived petroleum compounds are comprised of ~97% hydrocarbons with the remaining 3% made up of minor elements including nitrogen,
sulfur, and oxygen (NRC 2003). Polycyclic aromatic hydrocarbons (PAHs) comprise a small compositional percentage (0.2–7%) of crude oil, yet they are considered the most toxic components primarily due to their metabolites (James and
Kleinow 1994; NRC 2003). The toxic potential of PAHs in fish exposed during oil
spills have been well documented and reviewed extensively in the literature (e.g.,
Reynaud and Deschaux 2006; Beyer et al. 2016). Following DWH, a number of
studies focusing on sub-lethal impacts examined a range of adverse acute and
chronic effects, including skin lesions, cardiotoxicity, liver abnormalities, respiration changes, reproductive irregularities, histopathological changes, and also mortality (Murawski et al. 2014; Incardona et al. 2014; Brown-Peterson et al. 2015a, b;
Klinger et al. 2015; Bentivegna et al. 2015; Hedgpeth and Griffitt 2016; Esbaugh
et al. 2016; Olson et al. 2016; Grosell et al. 2020; Portnoy et al. 2020).
Toxicity testing has, in the past, concentrated on laboratory exposures using relatively high-dose concentrations (to elicit effects) and with “model” organisms, not
usually found in actual spills. Consequently, using laboratory-based toxicity experiments can be problematic when making inferences about potential impacts in wild fish
at environmentally relevant pollutant concentrations. Nevertheless, consistent sublethal effects have been observed between laboratory studies and field studies. This
chapter explores sub-lethal effects observed primarily from sampling of naturally
occurring fish populations in the GoM following two major oil spills, the Deepwater
Horizon and the Ixtoc 1. In the case of the Ixtoc 1 spill, few fishes (perhaps a few long24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…