396
highly variable depending on the species. For instance, the impact on high-quality
habitat was much higher for blackfin tuna habitat (19%) compared to those critical
areas for sailfish and blue marlin (<10%). This was largely due to the pattern of
habitat usage, outer and upper shelf (i.e., blackfin tuna) versus the slope and abyssal
regions (i.e., sailfish). Furthermore, electronic tagging revealed that the core usage
areas of adult blue marlin shifted from the northwestern and north central GoM to a
more limited western GoM usage following DWH. There was a twofold decrease in
the usage of areas impacted by DWH in 2010 compared to previous years, possibly
indicating they did not return to their spawning areas due to adverse environmental
conditions, perhaps as a result of chemical cues, changes in prey distributions, or
other factors (Rooker et al. 2013).
Significant declines and community structure shifts were observed in reef fish
located on artificial reef systems in the northern GoM between 2009–2010 and
2011–2012 (Dahl et al. 2016). This decline ensued during the simultaneous occurrence of the lionfish (Pterois spp.) invasion and the DWH oil spill in the northern
GoM. Experimental removal of lionfish had significant impacts on reef fish community structure, predominantly on the smaller lionfish prey fishes and obligate reef
residents (e.g., damselfishes, cardinalfishes, wrasses, blennies, etc.). However, there
were no substantial gains observed in the overall native reef fish abundance of most
taxa, including the larger snappers and gray triggerfish (Balistes capriscus). The
declines in these larger fishes are unlikely due to being directly consumed by lionfish and may be the result of direct oil spill mortality or emigration from oil spill
impacted areas. It is also highly plausible that environmental disturbances and habitat degradation caused by the DWH increased the system susceptibility and vulnerability (e.g., compromised immune systems in fish), allowing for a relatively
effortless lionfish invasion (Dahl et al. 2016).
In the SGoM, the Universidad Nacional Autónoma de Mexico (UNAM) conducted demersal fish surveys both pre-and post-Ixtoc 1. Results indicated that both
the number of fish species collected and the diversity of species decreased significantly in areas surrounding the spill site (Amezcua-Linares et al. 2015). The number
of fish species collected around the Ixtoc I spill area had decreased 38% between
1978 and 1980, pre- and post-spill, respectively. By 1982, 3 years post-spill, the
number of fish species collected was similar to those collected in 1978. However,
although the number of species rebounded, the pre- and post-spill assemblages were
significantly different. In fact, three species (rough scad, Trachurus lathami; Atlantic
thread herring, Opisthonema oglinum; and the blackcheek tonguefish, Symphurus
plaguisa) that were abundant before the Ixtoc 1 spill were never caught again. By
1982, there was 50% decrease in commercial landings compared to 1981 and a
significant composition change within Campeche Bay. Yet, the landings in 1982
were similar to pre-spill levels and higher than those in 1987 and 1989. These variations in landings could be due to environmental or seasonal fluctuations or changes
in fishing patterns (Gracia et al. 2020). The reduction in landings was suspected to
be directly related to larval stage mortalities, whereas the changes in composition
that occurred immediately after the spill appeared to be related to habitat shifts and
migrations to areas outside of the spill zone.
E. L. Pulster et al.
highly variable depending on the species. For instance, the impact on high-quality
habitat was much higher for blackfin tuna habitat (19%) compared to those critical
areas for sailfish and blue marlin (<10%). This was largely due to the pattern of
habitat usage, outer and upper shelf (i.e., blackfin tuna) versus the slope and abyssal
regions (i.e., sailfish). Furthermore, electronic tagging revealed that the core usage
areas of adult blue marlin shifted from the northwestern and north central GoM to a
more limited western GoM usage following DWH. There was a twofold decrease in
the usage of areas impacted by DWH in 2010 compared to previous years, possibly
indicating they did not return to their spawning areas due to adverse environmental
conditions, perhaps as a result of chemical cues, changes in prey distributions, or
other factors (Rooker et al. 2013).
Significant declines and community structure shifts were observed in reef fish
located on artificial reef systems in the northern GoM between 2009–2010 and
2011–2012 (Dahl et al. 2016). This decline ensued during the simultaneous occurrence of the lionfish (Pterois spp.) invasion and the DWH oil spill in the northern
GoM. Experimental removal of lionfish had significant impacts on reef fish community structure, predominantly on the smaller lionfish prey fishes and obligate reef
residents (e.g., damselfishes, cardinalfishes, wrasses, blennies, etc.). However, there
were no substantial gains observed in the overall native reef fish abundance of most
taxa, including the larger snappers and gray triggerfish (Balistes capriscus). The
declines in these larger fishes are unlikely due to being directly consumed by lionfish and may be the result of direct oil spill mortality or emigration from oil spill
impacted areas. It is also highly plausible that environmental disturbances and habitat degradation caused by the DWH increased the system susceptibility and vulnerability (e.g., compromised immune systems in fish), allowing for a relatively
effortless lionfish invasion (Dahl et al. 2016).
In the SGoM, the Universidad Nacional Autónoma de Mexico (UNAM) conducted demersal fish surveys both pre-and post-Ixtoc 1. Results indicated that both
the number of fish species collected and the diversity of species decreased significantly in areas surrounding the spill site (Amezcua-Linares et al. 2015). The number
of fish species collected around the Ixtoc I spill area had decreased 38% between
1978 and 1980, pre- and post-spill, respectively. By 1982, 3 years post-spill, the
number of fish species collected was similar to those collected in 1978. However,
although the number of species rebounded, the pre- and post-spill assemblages were
significantly different. In fact, three species (rough scad, Trachurus lathami; Atlantic
thread herring, Opisthonema oglinum; and the blackcheek tonguefish, Symphurus
plaguisa) that were abundant before the Ixtoc 1 spill were never caught again. By
1982, there was 50% decrease in commercial landings compared to 1981 and a
significant composition change within Campeche Bay. Yet, the landings in 1982
were similar to pre-spill levels and higher than those in 1987 and 1989. These variations in landings could be due to environmental or seasonal fluctuations or changes
in fishing patterns (Gracia et al. 2020). The reduction in landings was suspected to
be directly related to larval stage mortalities, whereas the changes in composition
that occurred immediately after the spill appeared to be related to habitat shifts and
migrations to areas outside of the spill zone.
E. L. Pulster et al.