401
(Brian et al. 2007). Furthermore, they had elevated glucose metabolism and glycolytic pathway activation, a common stress response in fishes (Naour et al. 2017).
Their immune profile included elevated cytokines and chemokines, indicative of an
ongoing inflammatory response (Wang and Secombes 2013). Multiple antiapoptotic and antioxidant genes were engaged, as a potential protective mechanism
against documented bile PAHs in the animals (Santana et al. 2018).
In addition, both oil field groups of fish (from DeSoto Canyon and Campeche
Bay) displayed differential gene expression from the non-oil field fish taken off the
Yucatan Peninsula. This was evidenced in the elevation of circadian rhythm genes,
chemokines, and pro-apoptotic genes and decreased gene expression associated
with blood coagulation and angiogenesis (Deak et al. 2018). This study underscores
the utility of transcriptomics in elucidating molecular discrepancies found in populations after large contamination events.
24.6 Insights from Histopathology
Histopathological techniques to detect cellular alterations have been used in laboratory and environmental exposures and are considered important tools to detect
direct toxic effects of chemical exposures (Schwaiger et al. 1997). Moreover, microscopic pathological studies have been used to differentiate between alterations that
result from natural environmental stressors and secondary stress effects of anthropogenic pollution (Snieszko 1974; Teh et al. 1997; Schwaiger et al. 1997).
Planar PCBs, dioxins, and PAHs are all known to exert biological effects through
aryl hydrocarbon receptor (AHR) signaling pathways evoking xenobiotic metabolism (i.e., cytochrome P450). The upregulation and expression of the CYP1A protein were detected in the gills, head kidney, and intestinal tissues from resident Gulf
killifish collected in Barataria Bay post-DWH in 2010 and 1 year later (Whitehead
et al. 2012; Dubansky et al. 2013, 2017). These CYP1A proteins were markedly
elevated in the fish collected at oiled sites compared to those at unoiled locations.
Additionally, body weights, germinal epithelium thickness, oocyte diameters, and
gonadal somatic indices from histological measurements measured in Gulf killifish
collected at impacted oil sites in Barataria Bay were all lower than those from nonimpacted sites (Carr et al. 2018). Higher lesion prevalence in the gill, liver, stomach,
and epithelial tissues of menhaden (Brevoortia sp.) was also observed in those collected in Barataria Bay compared to those collected along the north Atlantic coast
(Bentivegna et al. 2015).
Offshore species were also been evaluated for histopathological alterations following the DWH and Ixtoc 1 events. Red snapper and golden tilefish were routinely
sampled throughout the GoM over the course of 7 years (2011–2017; Murawski
et al. 2014; Snyder et al. 2015). A variety of tissue samples were collected for PAH
analysis and histopathology (Gracia et al. 2017, 2018; Snyder et al. 2019; Pulster
et al. 2018). Skin lesions observed in these species were confirmed through histology (Fig. 24.7). A subset of red snapper hepatic tissues collected in the north central
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…
(Brian et al. 2007). Furthermore, they had elevated glucose metabolism and glycolytic pathway activation, a common stress response in fishes (Naour et al. 2017).
Their immune profile included elevated cytokines and chemokines, indicative of an
ongoing inflammatory response (Wang and Secombes 2013). Multiple antiapoptotic and antioxidant genes were engaged, as a potential protective mechanism
against documented bile PAHs in the animals (Santana et al. 2018).
In addition, both oil field groups of fish (from DeSoto Canyon and Campeche
Bay) displayed differential gene expression from the non-oil field fish taken off the
Yucatan Peninsula. This was evidenced in the elevation of circadian rhythm genes,
chemokines, and pro-apoptotic genes and decreased gene expression associated
with blood coagulation and angiogenesis (Deak et al. 2018). This study underscores
the utility of transcriptomics in elucidating molecular discrepancies found in populations after large contamination events.
24.6 Insights from Histopathology
Histopathological techniques to detect cellular alterations have been used in laboratory and environmental exposures and are considered important tools to detect
direct toxic effects of chemical exposures (Schwaiger et al. 1997). Moreover, microscopic pathological studies have been used to differentiate between alterations that
result from natural environmental stressors and secondary stress effects of anthropogenic pollution (Snieszko 1974; Teh et al. 1997; Schwaiger et al. 1997).
Planar PCBs, dioxins, and PAHs are all known to exert biological effects through
aryl hydrocarbon receptor (AHR) signaling pathways evoking xenobiotic metabolism (i.e., cytochrome P450). The upregulation and expression of the CYP1A protein were detected in the gills, head kidney, and intestinal tissues from resident Gulf
killifish collected in Barataria Bay post-DWH in 2010 and 1 year later (Whitehead
et al. 2012; Dubansky et al. 2013, 2017). These CYP1A proteins were markedly
elevated in the fish collected at oiled sites compared to those at unoiled locations.
Additionally, body weights, germinal epithelium thickness, oocyte diameters, and
gonadal somatic indices from histological measurements measured in Gulf killifish
collected at impacted oil sites in Barataria Bay were all lower than those from nonimpacted sites (Carr et al. 2018). Higher lesion prevalence in the gill, liver, stomach,
and epithelial tissues of menhaden (Brevoortia sp.) was also observed in those collected in Barataria Bay compared to those collected along the north Atlantic coast
(Bentivegna et al. 2015).
Offshore species were also been evaluated for histopathological alterations following the DWH and Ixtoc 1 events. Red snapper and golden tilefish were routinely
sampled throughout the GoM over the course of 7 years (2011–2017; Murawski
et al. 2014; Snyder et al. 2015). A variety of tissue samples were collected for PAH
analysis and histopathology (Gracia et al. 2017, 2018; Snyder et al. 2019; Pulster
et al. 2018). Skin lesions observed in these species were confirmed through histology (Fig. 24.7). A subset of red snapper hepatic tissues collected in the north central
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…