Thursday, January 17, 2013

Minnow Mystery Unmasked

Drayton Sanders from Dalton, Georgia had captured some really interesting fish behavior on camera recently and sent the photos to the Tennessee Aquarium for some answers. "We always take out of town guests up to see the Aquarium. I can never get enough," Drayton said. "Here are some pictures of a fish hatch that I photographed in a stream near Cashiers, North Carolina. There were several groups of these attracting trout as you can see. I would be interested in knowing a little more about them if you can help."
Drayton's images were examined by one of the scientists from the Tennessee Aquarium Conservation Institute, TNACI, and Dr. David Neely, another freshwater fish expert. Dr. Bernie Kuhajda is a TNACI aquatic conservation biologist who loves talking about freshwater species - especially southeastern species. And he LOVED Drayton's pictures. 

Here is Dr. Kuhajda's explanation of what Drayton captured: “These are really cool photos of hundreds of red and yellow adult Yellowfin Shiners (Notropis lutipinnis) spawning over the pebble nests of the large gray-green minnow, which is a River Chub (Nocomis micropogon), seen among the brightly-colored shiners. 

There are no trout in the photos.  

The male chubs build a pile of pebbles one at a time, spawn with a female, and cover the eggs with more pebbles.  The shiners spawn in the water column above the chub nests and rely on the chubs to cover their eggs with pebbles and guard them from predators.  

The chubs benefit by having most of the eggs in their nest that are not theirs, so if a predator eats an egg it is likely not a chub egg.  Pretty neat!”

Drayton wrote back to say, "Thank you so very much. This is wonderful! I'm so pleased to have such information. Indeed, after the shiners were gone, there was a buildup of pebbles in the creek bed as you described," wrote Drayton.