Are offshore fish about to be stunned?
By: Bill Hitchcock
Are we about to have an offshore cold stun event? Are we about to see offshore fish floating on top of the water out by the Gulf Stream due to extreme temperature differentials? That’s a good question because right now conditions seem conducive for it to happen.
A cold stun event is a naturally occurring phenomenon. It is a hypothermic reaction fish have when exposed to unusually cold water conditions. This reaction can happen over a period of time such as the case of the recent speckled trout cold stun event in Carteret County. Trout that were located up in the shallow head-ends of certain creeks and rivers became stunned as the air temperatures remained unusually low over an extended period of time. As the air temperatures remain cold, the water temperatures gradually declined. These fish became increasingly lethargic and eventually stunned.
An Offshore cold stun event is a bit different. These usually occur when very cold waters and very warm waters get pushed up together. In a very short distance a fish swims from 60-70 degree waters to 30-40 degree waters. This rapid change from warm to cold waters stuns the fish.
Two areas to look at in the image of sea water temperatures above. Southeast off the Point of Hatteras you can see where two water temperature extremes meet. Red and orange waters of the Gulf Stream area butting up against the pink and purple colored waters of the Labrador Current.
Of equal interest is almost due east out of Oregon Inlet. Here you can see a couple of cold water eddies (which rotate counter clockwise) influencing the warm waters of the Gulf Stream. The rotation of the cold water eddy is wrapping the warm waters (which rotate clockwise) around itself. Fish follow currents. So it is possible that any fish swimming in the cold water eddy can confront the surrounding warm waters and vice versa.
There is nothing unusual about the offshore water temperatures that are present. The cold waters from the north move south to their farthest extent to around Ocracoke Inlet in February. The Gulf Stream comes up to the Point of Hatteras then bares east towards the UK. The temperature differences between the two currents are typical. But if a cold or warm water eddy branches off or if the two currents move too close to each other-Then we have the potential of a cold stun event. The satellite image of the sea water surface above shows us that potential.
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February 2nd, 2010
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