The Opah (Lampris guttatus) has recently been determined to be the first known warm-blooded (or endothermic) fish according to researchers from NOAA’s Southwest Fisheries Science Center. The Opah (commonly referred to being the size of a car tire) uses this ability as an advantage when tracking prey. It allows them to move faster and display faster reaction times in cold, deep waters. Researchers discovered that the Opah was warm-blooded when examining gill tissue and realized that warm, deoxygenated blood moving from the extremities to the gills warmed cold oxygenated blood traveling from the gills to the rest of the body (also known as a counter-current exchange system). Fish are commonly cold-blooded or exothermic and acquire heat from their surrounding environment. Some fish such as tuna exhibit regional endothermy in muscles to allow them to swim faster in cold waters while the Opah is the only fish known to exhibit complete endothermy because heat exchange in the gills heats the entire body (including the internal organs). This allows the Opah to remain at cold depths for a longer period of time. A competitive advantage over other deep sea predators.
About the illustration: It always amazes me how much we don’t know about the natural world and the nifty adaptations that allow an organism to inhabit an otherwise inhospitable environment. Besides, how could I not draw a fish in a Hawaiian shirt with sunglasses?
For those of you who are able to access Science online, you can read the full article reporting the discovery here: http://www.sciencemag.org/content/348/6236/786
For those of you who cannot access Science online, you can read the announcement of the finding on the NOAA Fisheries Southwest Fisheries Science Center’s website here: https://swfsc.noaa.gov/news.aspx?ParentMenuId=39&id=20466