397
24.5 Immunotoxicity and Other Health Indices
Oil exposure has been linked to immunosuppression in a number of aquatic organisms, including marine mammals (De Guise et al. 2017; White et al. 2017) and fish
(Reynaud and Deschaux 2006; Barron 2012; Bayha et al. 2017). Immunosuppression
and immunotoxicity can result in a number of sub-lethal effects, such as enhanced
or suppressed cell proliferation, decreased phagocytosis, and induced cell apoptosis, which may eventually result in disease, decreased resiliency, community structure changes, mortality, and ultimately population declines (Reynaud and Deschaux
2006; Kim et al. 2013; Lee et al. 2018). Sub-lethal negative health effects of PAH
exposure on fishes are traditionally measured using biomarkers for immunotoxicity,
oxidative stress, and genotoxicity (Ameur et al. 2015; Benedetti et al. 2015; Javed
et al. 2017). However, biomarker responses can vary depending upon species, sex,
reproductive status, size, and location of collection (Balfry and Iwama 2004;
Fonseca et al. 2011; Wunderlich et al. 2015; Rehberger et al. 2017). Thus, for meaningful analysis of changes in health status of non-model species, reference intervals
should first be established, which describe the response values for a biomarker in
95% of a representative population (Geffré et al. 2009).
Post-DWH, fish surveys conducted in 2011 and 2012 evaluated the disease status
of over 7000 fishes (>100 species) collected from 150 sampling locations in the
northern GoM (Murawski et al. 2014). In 2011, the incidence of skin lesions varied
with species; however, the prevalence rates were higher in the demersal fishes such
as tilefish (Lopholatilus chamaeleonticeps), snappers, and groupers compared to
elasmobranchs (Fig. 24.3a). The frequencies of lesions ranged from ≤1% in elasmobranchs to ~5% in red snapper and upward of 10% in bottom dwelling tilefish.
The overall frequency of skin lesions dropped significantly from 1.9% to 0.9%
(p = 0.019) between 2011 and 2012. The hypothesis that DWH oil exposure was the
cause of increased lesion frequency could not be rejected. Data collected subsequent to those published in the Murawski et al. (2014) paper (Fig. 24.3b) show
further declines in lesion frequency to zero in 2015, with a slight uptick in 2017.
Lesions were also observed in red drum (Sciaenops ocellatus) collected at several
sites within Barataria Bay, Louisiana, where surveys documented moderate to heavy
oiling following DWH (Harr et al. 2018). Of the red drum examined, 87% of fish
assessed from impacted sites within Barataria Bay presented pathological changes
in the skin. Moreover, lesions were induced in southern flounder (Fig. 24.4) exposed
to oil and pathogens providing direct evidence that oil exposure induces immunosuppression, elevated bacteria levels, and increased incidences of bacterial infections (e.g., skin lesions; Bayha et al. 2017).
In addition, 18% of the red drum collected at impacted sites within Barataria Bay
were also anemic compared to 0% of the fish collected at non-impacted sites (Harr
et al. 2018). Bottlenose dolphins from this area also presented with anemia
(Schwacke et al. 2014). Lowered hemoglobin concentrations in fish have previously
been linked to oil exposures in a number of field and laboratory studies (Alkindi
et al. 1996; Khan 2003; Bayha et al. 2017).
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…
24.5 Immunotoxicity and Other Health Indices
Oil exposure has been linked to immunosuppression in a number of aquatic organisms, including marine mammals (De Guise et al. 2017; White et al. 2017) and fish
(Reynaud and Deschaux 2006; Barron 2012; Bayha et al. 2017). Immunosuppression
and immunotoxicity can result in a number of sub-lethal effects, such as enhanced
or suppressed cell proliferation, decreased phagocytosis, and induced cell apoptosis, which may eventually result in disease, decreased resiliency, community structure changes, mortality, and ultimately population declines (Reynaud and Deschaux
2006; Kim et al. 2013; Lee et al. 2018). Sub-lethal negative health effects of PAH
exposure on fishes are traditionally measured using biomarkers for immunotoxicity,
oxidative stress, and genotoxicity (Ameur et al. 2015; Benedetti et al. 2015; Javed
et al. 2017). However, biomarker responses can vary depending upon species, sex,
reproductive status, size, and location of collection (Balfry and Iwama 2004;
Fonseca et al. 2011; Wunderlich et al. 2015; Rehberger et al. 2017). Thus, for meaningful analysis of changes in health status of non-model species, reference intervals
should first be established, which describe the response values for a biomarker in
95% of a representative population (Geffré et al. 2009).
Post-DWH, fish surveys conducted in 2011 and 2012 evaluated the disease status
of over 7000 fishes (>100 species) collected from 150 sampling locations in the
northern GoM (Murawski et al. 2014). In 2011, the incidence of skin lesions varied
with species; however, the prevalence rates were higher in the demersal fishes such
as tilefish (Lopholatilus chamaeleonticeps), snappers, and groupers compared to
elasmobranchs (Fig. 24.3a). The frequencies of lesions ranged from ≤1% in elasmobranchs to ~5% in red snapper and upward of 10% in bottom dwelling tilefish.
The overall frequency of skin lesions dropped significantly from 1.9% to 0.9%
(p = 0.019) between 2011 and 2012. The hypothesis that DWH oil exposure was the
cause of increased lesion frequency could not be rejected. Data collected subsequent to those published in the Murawski et al. (2014) paper (Fig. 24.3b) show
further declines in lesion frequency to zero in 2015, with a slight uptick in 2017.
Lesions were also observed in red drum (Sciaenops ocellatus) collected at several
sites within Barataria Bay, Louisiana, where surveys documented moderate to heavy
oiling following DWH (Harr et al. 2018). Of the red drum examined, 87% of fish
assessed from impacted sites within Barataria Bay presented pathological changes
in the skin. Moreover, lesions were induced in southern flounder (Fig. 24.4) exposed
to oil and pathogens providing direct evidence that oil exposure induces immunosuppression, elevated bacteria levels, and increased incidences of bacterial infections (e.g., skin lesions; Bayha et al. 2017).
In addition, 18% of the red drum collected at impacted sites within Barataria Bay
were also anemic compared to 0% of the fish collected at non-impacted sites (Harr
et al. 2018). Bottlenose dolphins from this area also presented with anemia
(Schwacke et al. 2014). Lowered hemoglobin concentrations in fish have previously
been linked to oil exposures in a number of field and laboratory studies (Alkindi
et al. 1996; Khan 2003; Bayha et al. 2017).
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…