5A and B) while the MMCs from the oil exposed killifish were

significantly greater in number in comparison to the control killifish (Fig. 5C and D). Overall, splenic MMCs from the oil-exposed sea trout were much larger than those from control fish (Fig. 5B and D and Table 1). Spleen tissues and peripheral blood from Gulf killifish collected from Terrebonne Bay in August 2010, and sea trout collected from the north eastern Gulf of Mexico in November find more 2010 demonstrated changes suggesting exposure to hydrocarbons. The blood cell changes were similar to those associated with increased disease susceptibility, and the tissue changes were indicative of environmental stress. Similar conclusions Pifithrin-�� molecular weight regarding fish health were made following the EVOS in Prince William Sound, Alaska in 1989. Oil exposure resulted in significant mortality and physical and genetic abnormalities in Pacific herring (Marty et al., 1999). Fish population declines began the year following the EVOS (Thorne and Thomas, 2008) and increased occurrence of fish diseases continued for several years (Carls et al., 1998). Following the EVOS, several studies were performed in contaminated and non-contaminated areas of Prince William Sound. Higher mortality and increased occurrence of lesions in Pacific herring (Clupea pallasi) exposed to water contaminated with

weathered crude oil were significantly correlated to water TPAH concentrations ( Carls et al., 1998). In three other studies, herring eggs and/or larva were collected from oiled and un-oiled beaches immediately after the EVOS. Eggs and/or larva exposed to oil had significantly PIK-5 more morphological deformities and cytogenetic damage and higher mortality ( Hose et al., 1996, McGurk and Brown, 1996 and Norcross et al., 1996). Additionally, examination of tissues

of adult herring revealed hepatic necrosis and an increased score for melano-macrophage aggregates. Significantly higher levels of tissue PAH concentrations were present in exposed fish ( Marty et al., 1999). Increased occurrences of external lesions and diseases have occurred in twenty species of fish since the 2010 oil spill (Cowan, 2013). Many pollutants accumulate in aquatic ecosystems. Stress can affect cellular distributions in fish hematopoietic tissues resulting in decreased lymphocyte and hemoblast counts, and increased granulocyte counts (Peters and Schwarzer, 1985). Hematology is an indicator of immunological status and can provide definitive diagnoses (Duncan et al., 1994 and Campbell and Ellis, 2007). The role of white blood cells is to defend against pathogens (Marieb and Hoehn, 2010). Exposing humans to fuel and petroleum products resulted in significant decreases of white blood cells, or leukocytopenia (d’Azevedo et al., 1996 and Okoro et al., 2006). Carls et al.