Eastern Shore Jubilee

Jubilee Alligator2

The rarest of photos — an alligator eating a flounder during a Jubilee — Thursday in Daphne. Coastal Alabama is literally the only place in the world where you could witness a scene like this. Jubilees are the stuff of legend, but they are very much real. One of the strangest natural phenomena in the world, Jubilees occur on rare occasions, when conditions are just right. Thousands of fish, crabs, and shrimp move from deeper waters of the Bay, congregating in great numbers in the shallow waters near the shoreline. The "free" seafood is so plentiful and easy to catch that locals rush to the bank and harvest the critters, using dip-nets or their bare hands. For many it’s a once-in-a-life time experience, but Jubilees have been going since before man arrived in the area. We believe this picture could be — the first photo-documentation— of how alligators take advantage of the bonanza. Native Fairhope resident and long-time outdoorsman, Frank Potter, snapped the incredible shot and then observed the alligator eating another 7 or 8 flounders in a row!

SO JUST WHAT IS A JUBILEE?THE SCIENCE: Jubilees are caused primarily by the upward movement of oxygen-poor bottom waters that force bottom-dwelling creatures ashore. Bottom water low in oxygen results from several circumstances that happen at the same time: Pockets of salty water accumulate in the deeper parts of Mobile Bay and stagnate during calm conditions during summer months. Then stratification, or the layering effect of water containing different levels of salt, occurs when dense salty Gulf water is overlain by less dense, freshwater from the rivers. When water is stratified or layered in this way, the layers don’t get mixed, preventing the movement of oxygen from the air down into the bottom water layer. Water temperature also influences the stratification of the water and is an important cause of a Jubilee event. Warm water holds much less oxygen than cooler water. The shallow depth (average depth 10ft) of Mobile Bay causes the water temperatures to get very high in the summer months. This is the primary reason why Jubilees only occur in summer. Phytoplankton, (plant plankton), also play an important role in the occurrences of Jubilees. Plankton, along with other microorganisms, form the base of the estuarine food web that feeds many larger organisms in the Bay. At night, phytoplankton are unable to carry on photosynthesis and must take in tremendous quantities of dissolved oxygen from the water in order to sustain themselves. The more phytoplankton in the water, the more dissolved oxygen gets taken out of the near-surface water at night. This can cause the water near the surface to become depleted of dissolved oxygen. Normally, the worst oxygen-poor water remains at greater depths within Mobile Bay. However — if a gentle easterly wind creates a surface current— it will move the top layer of water from east to west, from near shore to offshore. As a result, the oxygen-poor bottom water gets pushed shoreward by a rising or incoming tide from the Gulf.

As this tide-driven, salty, low-oxygen water moves shoreward, sea creatures in its path are “driven” in front of it. Animals that are good swimmers can easily swim over the top of the advancing low-oxygen water mass, but the slower paced organisms, such as crabs and flounder, must flee toward the shore (away from the low-oxygen water) as they try to get oxygen from the shallow water nearer the water’s surface. That is why sea-life like flounders, crabs, shrimp, and stingrays are most often seen at Jubilees. Jubilee events are known to occur regularly in two places: Mobile Bay, AL and in Tokyo Bay, Japan.

For more information on the phenomenon of Jubilees, visit https://coast.noaa.gov/.../the-jubilee-phenomenon-teacher...As part of our work, MBNEP contracted Thompson Engineering — together we are creating a detailed scientific Plan for the preservation and restoration of our coastal waters and our way of life on the Eastern Shore. Citizen feedback is crucial in the creation of our Plan. If you care about the Eastern Shore and its waters and would like to include your input, please visit: https://www.mobilebaynep.com/.../the-eastern-shore-an...MBNEP offers many thanks to citizen photographer Frank Potter for sharing his remarkable photo.