When life gives you lemons, you should
probably assess their mating characteristics, growth, and survival.
At the beginning of April I arrived at
Bimini Biological Field Station in the Bahamas for a 3 month stay. I am currently
working at the Shark Lab and assisting with various research projects. I exited
the airport and was whisked right onto a boat to tag hammerheads, and since
then it’s been a whirlwind of coming into contact with seven different species
of sharks, learning the ins and outs of the lab and all of its research, and
being part of an amazing and very international crew. Since I arrived, one
thing has stayed constant: the perpetual preparation for the biggest research
project of the year, PIT.
May 24th was a day we had heard
about for months: we had built countless pens, inventoried pen mesh, scavenged
cinder blocks, checked all of our equipment, repaired gillnets, and boats, and
readied ourselves for a total of 12 days actively in the field where we would tag and
collect data on juvenile lemon sharks in North Bimini.
We are a group 20-30 year olds from all
over the world, including Brazil, England, the U.S., Canada, Australia, and
France. We call this annual project, PIT, which stands for Passive Integrated
Transponder, the type of tags we implant in these juvenile lemon sharks. This
type of tag is about the size of a grain of rice and when scanned, it provides
a unique “barcode” for each individual. We use this string of numbers to
identify each shark. This is the same type of tag that you might have implanted
in your pet. It has a low shed rate and no harmful effects on the sharks. We
inject these tiny tags into the area around the base of the dorsal fin and that
is where they remain for life.
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| (The rice grain sized PIT tag) |
So why do we do PIT and what kind of data
do we collect? The 12 days we spend in the field are split between two separate
locations, Sharkland and the North Sound. These two areas are nurseries for
juvenile lemon sharks. Bimini is unique in that it has some of the only viable
nursery grounds for quite a few miles. Because of this, these baby sharks
cannot migrate out of this area for at least 3 years for fear of getting preyed
upon. The lemons usually stay in the mangroves for 4-5 years and do very well
in semi-captivity. We use gillnets (normally illegal in Bimini, but we have a
research permit) to capture the sharks; there are 3 different nets set up in
each area, and we do checks on these nets every 15 minutes. If we capture a
shark, we quickly transport it to a nearby pen, where the tagging team works it
up. This team weighs, measures, sexes, takes a DNA and isotope sample, and tags
the shark. The sharks are then moved into holding pens based on their precaudal
length. Some of the sharks are then selected to be part of behavioral trials
run by the PhD students that we have here.
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| (Holding pens with trials pens in the background of North Sound nursery) |
This is our 21st year of PIT,
and in those 21 years we have collected around 4,000 genetic samples. We are
specifically looking at survival. mating characteristics, and growth. On
average, we catch about 200 sharks each year between both nurseries. The first
two days are usually the most hectic (our first day brought in 64 little
lemons), and then numbers tend to decrease. In our first 6 days, we caught a
total of 107 sharks! (numbers of recap and new sharks). On average, we catch
99% of the juvenile lemon sharks in these nurseries.
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| (Liam our Masters project student removes a shark from the gillnet) |
If one of us briefly described the PIT
experience to you, it is probable that you would think we are out of our minds.
We definitely are, but that makes it all the more enjoyable. We usually are out
to set our nets around 6pm and we haul around 6am. We spend 12 glorious hours
on the water combatting rain, bugs, and boats that spontaneously decide to not
function properly. We live for the midnight food runs where we get dinner (the
joys of being on a nocturnal schedule), snacks, and hot beverages. We spend the
majority of the night being rather damp, but I have never met a group of people
that do a better job of making what could be a relatively uncomfortable
situation incredibly fun. We had dazzling sunsets, and our radio chatter was
pretty hilarious if I do say so myself. We often blasted “pump up” songs over
the radio to set our nets and keep the morale high. We had many a dance party
complete with our favorite Brazilian doing a drive-by as he was thrusting the
air, and I have never laughed as much as I did in these first 6 days of PIT.
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| (The food run/tagging boat, delivering dinner to nets at about midnight) |
There are 3-4 people per boat, and this is
your team. Your team remains the same for 3 days and then we change everything
up. We rotate jobs, including driving the boat, lighting up the net, and doing
walk checks if necessary. There were also plenty of chances to get competitive
with your team. We had trivia competitions for brownies in our snack boxes (I
challenge you to come up with a more sought after prize), we played a Shark Lab
version of Cards Against Humanity, we had an auction for a mysterious dry bag
filled with goodies, and we played a game where we listened to backwards songs over
the radio and we had to guess what they were (surprisingly difficult and pretty
creepy sounding). Some people napped between checks while others went through
multiple ipods worth of music and podcasts, stargazed once the moon set, and chatted
with their boat members. We went through moments of craziness (my boat made
friends with and named a resident crab who hung out on our net) and by the end
of 6 days everyone looked a little insane. We are currently finishing up a
weeklong hiatus between nurseries which we use to fix everything, do behavioral
trials, release sharks, and prepare for the 6 days in the North Sound. June 7th
will mark the beginning of our next round of six nocturnal days!
So far it has been a pleasure to be part of
such an enthusiastic team and one so passionate about shark research and
conservation. We are all extremely lucky to be a part of such important work,
and if you want to learn more about the lab and its research, visit:
http://www.biminisharklab.com/
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