In Honor of Motherhood: Birthing in Bimini (5/10/2014)

In the photo above, taken last April, our former lab manager, Jill Brooks, inserts an acoustic transmitter into the body cavity of an adult, female lemon shark (total length--231 cm). She then took a genetic sample from this female’s dorsal fin. 

One month ago, we downloaded our receiver data near the tip of South Bimini. This same female was acoustically detected by receivers on April 10th, almost a year later, and has lingered around these past weeks since, just in time for lemon birthing season...
Is this lemon pregnant? Last year she straddled the fence of sexual maturity, ultimately proving not to be.  After a year of further development, maybe this is her big debut. Soon we shall find out. And we don’t have to recapture her or observe her birthing to know for sure.

This is because, in June of this year, the lab will perform its 20th annual PIT project, a twelve night ordeal where we use gillnets to capture, then tag and measure almost the entire population of baby and juvenile lemons in the Bimini mangrove nurseries. Recaptured juveniles from past years already have electronic PIT microtags (also called RFID tags with unique ID codes) inserted, so we can measure their growth and weight gains.  But the newborns, called neonates, will all be captured for the first time, PIT-tagged, and DNA sampled.

The above photograph shows a fin-clipping, which will soon be shipped to the states for genetic analysis. It is placed in a DMSO-filled vial to prevent DNA denaturation.

With our increasing archive of genetic material, each year we expand the family tree of Bimini’s lemon sharks to piece together a pedigree of interrelatedness. This pioneering research project can open the door for understanding the behavior and ecology of sharks down the line, paving the way for possible studies in social preference for familiars and kin. None of this, of course, could be done without the magic of the mothers, bringing a new batch of neonates to Bimini with each year. Just wanted to acknowledge the marvel at this relevant time. Happy Mother's Day!