393
sea urchins, kelp forests, fish, and invertebrates, was substantially changed
post-EVOS.
Stable isotope ratios are frequently used as indicators of trophic position and diet
compositions due to the differential fractionation of organic sources (i.e., marine vs.
terrestrial). Therefore, stable isotopes have been used as a tool to reconstruct potential diet and/or trophic level shifts by marine species as a result of oil exposures.
Isotopic ratios were evaluated in a number of species both pre- and post-DWH in
order to identify potential diet or trophic level shifts (Graham et al. 2010; Tarnecki
and Patterson 2015; Quintana-Rizzo et al. 2015; Ransom et al. 2016). Isotopic signatures from Spanish mackerel larvae appeared stable over time (2007–2011), yet
monthly comparisons revealed a depletion of δ
13
C during periods of peak oil coverage in coastal sites (June 2010) followed by an enrichment in δ
13
C and δ
15
N in later
months (August 2010). This pattern of carbon depletion was consistent with those
observed in mesozooplankton, suspended particulate samples, and mesopelagic fish
and shrimp (Graham et al. 2010; Quintana-Rizzo et al. 2015). Depletion of carbon
isotope values was suspected to be the result of trophic transfer of oil-derived carbon through the food web rather than strictly the presence of oil in the water column
(Graham et al. 2010). Following the oil spill, nitrogen enrichment was observed in
Spanish mackerel, red snapper, and mesopelagic fish and shrimp indicating dietary
and/or trophic shifts (Quintana-Rizzo et al. 2015; Ransom et al. 2016; Tarnecki and
Patterson 2015). Additional supporting evidence of dietary and trophic shifts were
observed in red snapper through the additional analysis of δ
34
S and gut contents
(Tarnecki and Patterson 2015; Patterson III et al. 2020). Results indicated an
increase in trophic level and a shift in diet from pelagic zooplankton prey to benthic
decapods and fish which persisted weeks to months following DWH (Fig. 24.2).
What is unknown is how this shift in elemental compounds of nitrogen, carbon, and
other constituents impacted the food value (if at all) and implications for resource
production.
24.4 Habitat Shifts
In general, fishes are highly mobile with daily movements and migrations that range
from small to large scale depending on species and life stage. Fish use a suite of
acoustic, olfactory, and visual sensory capabilities in order to detect, orient, and
discriminate between habitats and settlement locations (Arvedlund and Takemura
2006; Arvedlund and Kavanagh 2009; Paris et al. 2013; Díaz-Gil et al. 2017). Cues
from nutrients, natural degradation products (e.g., algal compounds), and anthropogenic chemicals, such as sunscreen, oil, fertilizers, etc., can result in habitat discrimination and altered selection (Hadfield and Paul 2011; Paris et al. 2013; Havel
and Fuiman 2016; Gouraguine et al. 2017). Specifically, cues from anthropogenic
chemicals have been demonstrated to alter fish behavior and increase habitat avoidance and are confound conspecific cues (Tierney et al. 2010; Kwan et al. 2015;
Lecchini et al. 2017). Of particular concern are the variety of hydrocarbons and
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…
sea urchins, kelp forests, fish, and invertebrates, was substantially changed
post-EVOS.
Stable isotope ratios are frequently used as indicators of trophic position and diet
compositions due to the differential fractionation of organic sources (i.e., marine vs.
terrestrial). Therefore, stable isotopes have been used as a tool to reconstruct potential diet and/or trophic level shifts by marine species as a result of oil exposures.
Isotopic ratios were evaluated in a number of species both pre- and post-DWH in
order to identify potential diet or trophic level shifts (Graham et al. 2010; Tarnecki
and Patterson 2015; Quintana-Rizzo et al. 2015; Ransom et al. 2016). Isotopic signatures from Spanish mackerel larvae appeared stable over time (2007–2011), yet
monthly comparisons revealed a depletion of δ
13
C during periods of peak oil coverage in coastal sites (June 2010) followed by an enrichment in δ
13
C and δ
15
N in later
months (August 2010). This pattern of carbon depletion was consistent with those
observed in mesozooplankton, suspended particulate samples, and mesopelagic fish
and shrimp (Graham et al. 2010; Quintana-Rizzo et al. 2015). Depletion of carbon
isotope values was suspected to be the result of trophic transfer of oil-derived carbon through the food web rather than strictly the presence of oil in the water column
(Graham et al. 2010). Following the oil spill, nitrogen enrichment was observed in
Spanish mackerel, red snapper, and mesopelagic fish and shrimp indicating dietary
and/or trophic shifts (Quintana-Rizzo et al. 2015; Ransom et al. 2016; Tarnecki and
Patterson 2015). Additional supporting evidence of dietary and trophic shifts were
observed in red snapper through the additional analysis of δ
34
S and gut contents
(Tarnecki and Patterson 2015; Patterson III et al. 2020). Results indicated an
increase in trophic level and a shift in diet from pelagic zooplankton prey to benthic
decapods and fish which persisted weeks to months following DWH (Fig. 24.2).
What is unknown is how this shift in elemental compounds of nitrogen, carbon, and
other constituents impacted the food value (if at all) and implications for resource
production.
24.4 Habitat Shifts
In general, fishes are highly mobile with daily movements and migrations that range
from small to large scale depending on species and life stage. Fish use a suite of
acoustic, olfactory, and visual sensory capabilities in order to detect, orient, and
discriminate between habitats and settlement locations (Arvedlund and Takemura
2006; Arvedlund and Kavanagh 2009; Paris et al. 2013; Díaz-Gil et al. 2017). Cues
from nutrients, natural degradation products (e.g., algal compounds), and anthropogenic chemicals, such as sunscreen, oil, fertilizers, etc., can result in habitat discrimination and altered selection (Hadfield and Paul 2011; Paris et al. 2013; Havel
and Fuiman 2016; Gouraguine et al. 2017). Specifically, cues from anthropogenic
chemicals have been demonstrated to alter fish behavior and increase habitat avoidance and are confound conspecific cues (Tierney et al. 2010; Kwan et al. 2015;
Lecchini et al. 2017). Of particular concern are the variety of hydrocarbons and
24 Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major…