Sunday, June 21, 2015

Snail Collection (and a bit about sex) - by Hannah Swim

It’s Friday morning which means I’m reaching for my swimsuit rather than my usual jean shorts and tank top. I groggily make my way to the kitchen for a quick bite to eat, grab my supplies for lab, and head straight for the boat ramp.  I see that the water is calm with a smooth glassy surface, perfect conditions for a morning kayak along the mangroves to collect snails.

The snails wait patiently to be returned to the
mangrove roots where they live.
I awkwardly heave the large yellow kayak off its rack behind the dive locker, and lug it down to the boat ramp.  It will not be one of my more graceful moments today, but my arms have gotten stronger after eight weeks of moving it in and out of the water. I haven’t been outside for more than 5 minutes and I’m starting to sweat in the heavy Caribbean humidity.  I think I’ll go for a quick swim after I get back. 

With my lifejacket on and falcon tubes between my legs I push off and begin to paddle my way around the dock.  Last week the water was rough so I am thankful that today it is calm which allows me to glide silently.   First stop is the area of mangroves just past the docks where I will drop off all the snails who have called these twenty some-odd falcon tubes, home for the past week.  Most are thrilled get ahold of some natural footing, others are a bit shyer after being pried off the lids and take a bit of time to come out of their shells again. I’m happy to wait for them to attach themselves to the branches, it is a beautiful morning.  Once my tubes are all empty I paddle north away from the docks. 

I start to collect snails from shady areas, under mangrove leaves and on low hanging branches.  I have found that setting them on top of the falcon tubes is the best way to let them come out of their shells.

How can you tell the sex? Well, the normal way, males
have a penis.  Just tip the shell up a little and have a look.
I am only interested in females, so the males are returned back to the mangroves where they will hopefully find a pretty lady to fertilize which we could collect next week. The whole collection process takes a little under and hour, and I am more than ready to take a quick dip before heading back to lab.  All my tubes have a new resident female snail with some sea water.  Most have already taken refuge on the bottom of the lids, and tend to remain there until they crawl into the water and spawn. 

The goal of this work is to find out when females release their larvae, but nailing down an exact time frame has proven more complicated than anticipated. With time we hope to be able to get a better grasp on their reproductive cycle and then we can use the newly hatched larvae to test their tolerance to heat stress.