As Arctic ice recedes, future oil spills pose increasing risk to keystone species and the ecosystems they support. We show that Polar cod (Boreogadus saida), an energy-rich forage fish for marine mammals, seabirds, and other fish, are highly sensitive to developmental impacts of crude oil. Transient oil exposures =300 µg/L during mid-organogenesis disrupted the normal patterning of the jaw as well as the formation and function of the heart, in a manner expected to be lethal to post-hatch larvae. More importantly, we found that exposure to lower levels of oil caused a dysregulation of lipid metabolism and growth that persisted in morphologically normal juveniles. As lipid content is critical for overwinter survival and recruitment, we anticipate Polar cod losses following Arctic oil spills as a consequence of both near-term and delayed mortality. These losses will likely influence energy flow within Arctic food webs in ways that are as-yet poorly understood.
The 1989 Exxon Valdez disaster exposed embryos of pink salmon and Pacific herring to crude oil in shoreline spawning habitats throughout Prince William Sound, Alaska. The herring fishery collapsed four years later. The role of the spill, if any, in this decline remains one of the most controversial unanswered questions in modern natural resource injury assessment. Crude oil disrupts excitation-contraction coupling in fish heart muscle cells, and we show here that salmon and herring exposed as embryos to trace levels of crude oil grow into juveniles with abnormal hearts and reduced cardiorespiratory function, the latter a key determinant of individual survival and population recruitment. Oil exposure during cardiogenesis led to specific defects in the outflow tract and compact myocardium, and a hypertrophic response in spongy myocardium, evident in juveniles 7 to 9 months after exposure. The thresholds for developmental cardiotoxicity were remarkably low, suggesting the scale of the Exxon Valdez impact in shoreline spawning habitats was much greater than previously appreciated. Moreover, an irreversible loss of cardiac fitness and consequent increases in delayed mortality in oil-exposed cohorts may have been important contributors to the delayed decline of pink salmon and herring stocks in Prince William Sound.
Cites: Science. 2014 Feb 14;343(6172):772-624531969
Cites: Integr Environ Assess Manag. 2007 Jul;3(3):351-6317695108
Cites: Comp Biochem Physiol A Mol Integr Physiol. 2000 Jun;126(2):161-7910938136
Cites: Philos Trans R Soc Lond B Biol Sci. 2007 Nov 29;362(1487):2017-3017553773
Cites: N Engl J Med. 2008 May 15;358(20):2148-5918480207
Cites: Environ Sci Technol. 2009 Jan 1;43(1):201-719209607
Cites: Gen Comp Endocrinol. 2010 Jul 1;167(3):387-9619800342
Cites: Comp Biochem Physiol A Mol Integr Physiol. 2002 Aug;132(4):797-81012095864
Cites: J Vet Med Sci. 2002 Sep;64(9):829-3312399609
Cites: Semin Cell Dev Biol. 2002 Dec;13(6):507-1312468254