marine biology

Night Swimming to see the Bioluminescence (aka "Shark Bait Night")

“Night Swim – 10$ - See the bioluminescence”.  The understated hand-painted wooden sign seemed harmless enough.  We were off the beaten path adventurers, right?  Rule 1) Refuse no invitation Rule 2) Don’t let fear win Rule 3) If its terrifying, it will be worth it.  Right? 


Honestly, I don’t know what we were thinking.  Perhaps we were caught in the moment – overwhelmed with the beauty and atmosphere of Drake Bay, Costa Rica.    Was it the fact that we had to take a boat through miles of mangrove-lined rivers and shoreline, passing crocodiles and being chased by dolphins, just to get to Drake Bay?  Was it the family of giant macaws living in the tree outside our cabin?  Did it make us feel invincible?  It must have.  Because let me tell you, I don’t swim in the ocean at night.  I barely swim in the ocean during the day. I can swim but I am not a particularly “strong” swimmer.   I have major shark phobia.  Not the normal, reasonable human adult type of shark fear but the type of shark phobia that revealed itself by way of a recurring childhood nightmare theme.  My nightmares have always included a scene of me, sleeping in a window-hammock of some sort, directly above a swimming pool containing a large, great white shark.  I’ve woken up a thousand times just before tumbling out of the hammock into the mouth of the hungry beast below.

I saw the sign.  I acknowledged it and continued walking on the gravel road back to our cabin.  I thought to myself, “sounds cool, I’ve always wanted to see bioluminescent plankton.”  While in a boat, or canoe.  Ashley, one of the friends with us on this trip, had a different idea – and if you think I am an unlikely candidate for this activity, Ashley is even less likely.  I don’t know what she was thinking either. Ashley wanted to go on the night swim.  Then Zach wanted to go.  Then Karin said, sure, we’ll do that.  “Um…..okay…we can do that,” I heard myself say.  

We made the phone call to Carlos with for more information.  He told us to meet him on the main beach at 9pm and we would walk to where it was the darkest and where the moon would not light up the water. The darker the better.  Um…yay.  He had lifejackets, a lantern and a dog with him.  So no boat, no canoes. 

We passed an inlet where the river met the ocean and it occurred to me to ask Carlos if there was any danger of running into sharks on this little swim.  He laughed, as if the question was ridiculous and said “No, there aren’t any sharks in Drake Bay.”  The logical part of my brain knew this had to be bullshit but at that moment, I NEEDED to believe him.  The further down the beach we walked, the harder my heart began to pound.   My hands were shaking.  It was so dark. 

 Carlos is an incredibly educated man.  He has lived in Drake Bay for almost 30 years.  I kept telling myself that if anyone could keep us safe, he could.  Carlos, and the little survival knife he brought with him, would not let shark eat us.  Karin, my strong, capable, amazing girlfriend, would not let a shark eat us.  She would figure out a way to fight it off. She figures out everything.

When we reached the spot on the beach where we could no longer see the moon, the town or each other’s faces, Carlos set down the lantern and handed out the lifejackets.  Apparently, the lantern’s purpose was to help us find our way back to the beach from the water.  The dog’s purpose was to sit on the beach and guard the lantern.

Carlos told us the further out we swam, the more we would see.  fantastic.  I was simultaneously grateful for the lifejacket and resentful of it.  I knew it would help to save me if a giant wave came along and swept me under the water but I also knew it would slow me down if I needed to get back to shore quickly.  Even the though the water was perfectly still, Carlos said it was not negotiable. 

The five of us walked into the water and kept going until our feet no longer touched the ocean floor.  We started to swim.  And kept swimming.  And kept swimming.  The lantern was only a speck in the distance when we finally stopped.  I was at once overcome with terror.   Then Carlos told us to look around us, to move our arms in the water, to slowly kick our feet.  He said the harder and faster we moved, the brighter they would shine.  My immediate thought was, “like an injured sea animal?” 

Then I saw the glowing droplets all around us.  In every direction fluorescent light moving through the water in perfect harmony with our actions.  If you raised your arms out of the water, hundreds of tiny lights rolled down them into the ocean around you.  The plankton seemed to react to our flailing and got more intense as we moved around.  For a few minutes, I forgot my fear and took in the experience.  I played with the glowing creatures, making them dance through my fingers and in my hair.  I let myself get lost in the warmth of the ocean around my body.  My friends and I shared a deeply spiritual experience.  Then I remembered we were still in the open ocean, in the blackness of night, and we had drifted pretty far apart from one another. 

In retrospect, we had probably only drifted about six feet from each other, but it felt like a football field to me.  I quickly swam over to Carlos and clung to his arm.  He was very patient and had dealt with frightened “adventurers” before.  I called to Karin and Zach and Ashley and asked everyone to “tighten up.”  I’m not too prideful to admit, I wanted to be in the middle of this huddle, and I was ready to go back to shore.  Finally, after a few more minutes, Carlos gave the signal and we headed back to the speck of yellow light in the distance.  I’ve never swam so fast in my life.  Poor Karin. I wish I could tell you I waited around to make sure she got to safety as well – but no, I knew Carlos had her back.   As we got closer to the shore, and the fear started to drift away, the enormity of what we had just experienced set in.  We had done something together that so few people will do.  I felt closer to nature, to the ocean, to my friends, to Karin.

Speaking of Karin, on the walk back to town she asked Carlos why there aren’t any sharks in Drake Bay.  He laughed and said, “of course there are sharks in Drake Bay. Lots of them.  Most people don’t ask me that on the way TO the night swim, though and I didn’t want to scare your friend.  But really, the sharks aren’t what we need to worry about.  It’s the crocodiles.  That river opening we walked past is where they their eggs. The babies swim around in the ocean near that river.”  Awesome.