425
stock-recruitment relationship of the two stocks arranged in biological years for
white (June to May) and pink shrimp (October to September) showed no clear
impact of Ixtoc 1 oil spill on the spawning stock and recruitment relationship
(Fig. 25.10). Spawning stock and recruitment numbers of both species showed similar behavior until 1983. The stock- recruitment trajectories suggest that variations
were within historical range before and after the Ixtoc 1 blowout. However, shrimp
populations then shifted to a lower abundance stage after the oil spill. It seems that
there was a sustained impact on the recruitment that affected the spawning stock
biomass. The question is if this was a long-term impact of the Ixtoc 1 oil spill.
Considering the annual renewal of shrimp populations is very unlikely and according to Gracia (1996) and Gracia and Vázquez- Bader (1998) is more related to overfishing due to emergence and development of intensive new artisanal fisheries acting
Fig. 25.10 Spawning stock-recruitment relationship (biological years) trajectories of white (a)
and pink shrimp (b) in the Ixtoc 1 area. Time periods circled are post-Ixtoc 1
25 Impacts of Deep Oil Spills on Fish and Fisheries
stock-recruitment relationship of the two stocks arranged in biological years for
white (June to May) and pink shrimp (October to September) showed no clear
impact of Ixtoc 1 oil spill on the spawning stock and recruitment relationship
(Fig. 25.10). Spawning stock and recruitment numbers of both species showed similar behavior until 1983. The stock- recruitment trajectories suggest that variations
were within historical range before and after the Ixtoc 1 blowout. However, shrimp
populations then shifted to a lower abundance stage after the oil spill. It seems that
there was a sustained impact on the recruitment that affected the spawning stock
biomass. The question is if this was a long-term impact of the Ixtoc 1 oil spill.
Considering the annual renewal of shrimp populations is very unlikely and according to Gracia (1996) and Gracia and Vázquez- Bader (1998) is more related to overfishing due to emergence and development of intensive new artisanal fisheries acting
Fig. 25.10 Spawning stock-recruitment relationship (biological years) trajectories of white (a)
and pink shrimp (b) in the Ixtoc 1 area. Time periods circled are post-Ixtoc 1
25 Impacts of Deep Oil Spills on Fish and Fisheries