419
Scientific evidence did not indicate a collapse or a clear impact on fisheries
(other than a near-term reduction due to closures in the NGoM) in the case of Ixtoc
1 or DWH. Although no dramatic oil spill impact on the fishery resources was registered at the population level, there is considerable evidence of impacts at the
organismal and sub-individual levels (Incardona et al. 2014, Dubansky et al. 2013,
Brown-Peterson et al. 2017; Pulster et al. 2019), and there is concern how these
effects could impact fishery resources in the long term. Murawski et al. (2016) point
out that although fishery landings rebounded in 1 or 2 years following the spill,
there may be impacts at the population level that could affect stock productivity.
These impacts could be differential depending on the life strategies of fish and shellfish. Species with a short life cycle may respond by either collapsing or recovering
quickly depending on the impact at the population level. In longer-lived species, the
impacts could manifest in the long term if spawning potential or growth rates are
affected. In order to analyze these responses, we selected three representative species or groups of commercial/recreational importance (red snapper, tuna, and pink
and white shrimp) with different habitats and ecological roles in the GoM (continental demersal platform, benthic, and pelagic-oceanic species) and compare their
behaviors in response to the two mega oil blowouts.
25.4 Red Snapper
Red snapper is a traditionally important fishing resource in the GoM and is also
sought as a valuable recreational species. Red snappers are bottom-dwelling and
distributed throughout the GoM and Caribbean. They live on sandy, rocky, muddy
bottoms and coral reefs. The red snapper can live for 50 years (Szedlmayer and
Shipp 1994; Wilson and Nieland 2001) and mature at age of 2. A female can produce up to 55 million eggs throughout her life (SEDAR7 2005). Spawning occurs
throughout the year, but mainly from April to September, with most reproduction
occurring between June and August (Collins et al. 1995). After hatching, larvae
remain in the pelagic environment from 26 to 30 days (Rooker et al. 2004; Gallaway
et al. 2007), go through a metamorphosis, and settle on the seabed in reefs, in rocky
habitats, or on shell remains in sand bottom. In the juvenile phase, under 2 years of
age, red snappers are caught incidentally by shrimp trawlers. After 2 years of age,
red snappers are subjected to fishing and remain so throughout their life (Gallaway
et al. 2009).
During the Ixtoc 1 oil spill, Mexican red snapper landings did not collapse.
Catches in 1979, 1980, and 1981 declined 7%, 35%, and 25%, respectively, in comparison to the average landings of the 1973–1978 pre-spill period (Fig. 25.4). Even
though there was a 35% decrease in the immediate post-spill year, landings were
similar to catches in 1976 and were in the range of observed fluctuations. Landings
quickly returned to pre-spill levels in 1982 and increased steadily until 1993 when
the historical maximum catch was attained. After the Ixtoc 1 oil spill, a long-term
impact was not apparent in red snapper landings in the SGoM. The steep decreasing
25 Impacts of Deep Oil Spills on Fish and Fisheries
Scientific evidence did not indicate a collapse or a clear impact on fisheries
(other than a near-term reduction due to closures in the NGoM) in the case of Ixtoc
1 or DWH. Although no dramatic oil spill impact on the fishery resources was registered at the population level, there is considerable evidence of impacts at the
organismal and sub-individual levels (Incardona et al. 2014, Dubansky et al. 2013,
Brown-Peterson et al. 2017; Pulster et al. 2019), and there is concern how these
effects could impact fishery resources in the long term. Murawski et al. (2016) point
out that although fishery landings rebounded in 1 or 2 years following the spill,
there may be impacts at the population level that could affect stock productivity.
These impacts could be differential depending on the life strategies of fish and shellfish. Species with a short life cycle may respond by either collapsing or recovering
quickly depending on the impact at the population level. In longer-lived species, the
impacts could manifest in the long term if spawning potential or growth rates are
affected. In order to analyze these responses, we selected three representative species or groups of commercial/recreational importance (red snapper, tuna, and pink
and white shrimp) with different habitats and ecological roles in the GoM (continental demersal platform, benthic, and pelagic-oceanic species) and compare their
behaviors in response to the two mega oil blowouts.
25.4 Red Snapper
Red snapper is a traditionally important fishing resource in the GoM and is also
sought as a valuable recreational species. Red snappers are bottom-dwelling and
distributed throughout the GoM and Caribbean. They live on sandy, rocky, muddy
bottoms and coral reefs. The red snapper can live for 50 years (Szedlmayer and
Shipp 1994; Wilson and Nieland 2001) and mature at age of 2. A female can produce up to 55 million eggs throughout her life (SEDAR7 2005). Spawning occurs
throughout the year, but mainly from April to September, with most reproduction
occurring between June and August (Collins et al. 1995). After hatching, larvae
remain in the pelagic environment from 26 to 30 days (Rooker et al. 2004; Gallaway
et al. 2007), go through a metamorphosis, and settle on the seabed in reefs, in rocky
habitats, or on shell remains in sand bottom. In the juvenile phase, under 2 years of
age, red snappers are caught incidentally by shrimp trawlers. After 2 years of age,
red snappers are subjected to fishing and remain so throughout their life (Gallaway
et al. 2009).
During the Ixtoc 1 oil spill, Mexican red snapper landings did not collapse.
Catches in 1979, 1980, and 1981 declined 7%, 35%, and 25%, respectively, in comparison to the average landings of the 1973–1978 pre-spill period (Fig. 25.4). Even
though there was a 35% decrease in the immediate post-spill year, landings were
similar to catches in 1976 and were in the range of observed fluctuations. Landings
quickly returned to pre-spill levels in 1982 and increased steadily until 1993 when
the historical maximum catch was attained. After the Ixtoc 1 oil spill, a long-term
impact was not apparent in red snapper landings in the SGoM. The steep decreasing
25 Impacts of Deep Oil Spills on Fish and Fisheries