Expedition leaders: Dr. Phil Matich and Sorantaa Bain

Crew: Cora, Rachel, Ryan, Sami, Tessie and Randan.

Introduction

A busy week full of shark tagging, receiver downloads, blue hole swims, storms, delicious dinners, lectures and more, dive in below!

Day 1

The team met at the airport in anticipation of our trip. Some of us had been to Andros before, but for others it was their first time visiting the island and helping with shark research. Everyone introduced themselves, checked in for the flight, and prepared for an exciting week.

The flight from Ft. Lauderdale to Fresh Creek was smooth, and as we approached Andros and the clouds disperse, the landscapes of West Side National Park emerged – an array of tidal creeks and salty low lands that look unreal. We landed after the ~1 hour flight, cleared immigration and customs, and were greeted by the previous team who had just finished up a successful week. We couldn’t wait to get started!

Once we got to Cargill Creek, we settled in and got the research gear ready. We ate lunch during a briefing where we learned about our objectives for the week.

We then loaded up the boat for an afternoon of sampling. We headed to a nearby patch reef and deployed our drumlines. It took a couple hours before our first bite, but our perseverance paid off – 2 nurse sharks, both over 2 meters took our baits. The crew quickly secured each of the sharks, checked to see if they had been previously tagged (they hadn’t), and tagged them with internal ID tags. The sharks we then measured, and fin, muscle, and blood samples were collected for dietary assessments.

The sun was starting to get low on the horizon after we released the second shark, so we picked up our gear and headed back to the lodge. Dinner was delicious as always, which was followed by a lecture on the sharks and rays of The Bahamas showing us what species we might encounter during the week.

Day 2

After waking up and enjoying breakfast, we loaded the boat and started traveling south toward our destination for the day. We had a few tasks to complete before our shark sampling though. One of the methods we use to study sharks is outfitting them with acoustic transmitters that allow us to track their distributions and movements. To do so, we deploy listening stations (receivers) in the water that records when the sharks with transmitters are close. Gathering the data requires retrieval of the receivers, so the team lead used SCUBA to collect them. Once on board, each receiver was cleaned, its data was downloaded, and the battery was changed so that it could be redeployed. After we finished downloading the receivers, it was on to tagging more sharks.

It didn’t take long for our first shark once our gear was in the water. Within one hour we caught, tagged, and released four Caribbean reef sharks, three of which were outfitted with acoustic transmitters that will allow us to track their movements for the next 10 years. Pictures of these sharks are limited, because we were met with a rainstorm while we were tagging these sharks. But the rain subsided, and we continued fishing for the rest of the afternoon.

We tagged more Caribbean reef sharks, and then made the drive back up north so that we were on time for dinner. We cleaned the gear, had dinner, and then enjoyed watching the local lemon sharks swimming in the water next to the lodge.

Day 3

Our third day took us out to the pelagic realm to seek out and tag silky sharks. After breakfast, we loaded the boat and headed offshore. It didn’t take long for the fish and sharks to show up, and we quickly caught, tagged, and released a small silky shark.

Our gear soaked for some time after, but unfortunately we didn’t have any more bites. As such, we headed inshore to try and tag more sharks in coral reef habitats. But not before a quick snorkel in the blue water.

And we were rewarded for our efforts with more Caribbean reef sharks, one of which was quite large. Based on her shape, we suspected that she was pregnant, which was confirmed by an ultrasound scan! Andros includes sharks of all sizes and life stages, and for Caribbean reef sharks, it appears that there is a nursery somewhere on the east side based on the capture of very small individuals as well as pregnant females. We ensure that we work up the sharks as quickly as we can, and this individual was no exception. We tagged, measured, and collected tissue samples from her, outfitted her with an acoustic transmitter to track her, and then released her.

It was another great day! We collected our gear and headed home. But not before another quick dip at a blue hole where we checked out local marine life like coral, fish, and lobsters. Blue holes create unique conditions that can lead to very productive environments, and the corals surrounding this blue hole serve as an important foundational group of species that support a very diverse marine community.

Dinner was followed by a discussion of tomorrow’s plan, then it was time for bed.

Day 4

The beginning of this day was similar to the others – gear preparation, breakfast, then loading up the boat to go. However, it was followed by more acoustic receiver retrievals before we started tagging sharks. Six more acoustic receivers were collected and cleaned, their data was downloaded, and their batteries were replaced before being redeployed in the water.

After finishing our morning of receiver downloads, we started tagging sharks. The area we went to was a nearshore, shallow reef system that serves as habitat for both very small sharks, and very large sharks. Today was a small shark day. Throughout the afternoon, we caught, sampled, tagged, and release four blacknose sharks – our first of the trip :) These sharks don’t get much bigger than 4 feet in length, but they are still feisty when they’re on the line. We quickly measured, tagged, and released all four sharks, which were all within 2 inches of length of one another!

When we catch several small sharks, it often means there aren’t any large sharks around. If they were, the smaller sharks would be more timid about eating the bait on our hooks. But today there was one more sharks, another Caribbean reef sharks that was nearly 6 feet in length. This female was a little smaller than the large shark we caught and tagged two days ago, but based on her size she could be carrying pups. So, we conducted an ultrasound scan to check. Unlike the shark from two days ago, she was not pregnant, but it was important to check, and knowing she wasn’t pregnant is also useful information. And she was a recapture – we previously tagged her two years ago in the same area, suggesting this is an important habitat for mature, female reef sharks.

The wind started picking up, so we decided to collect our gear and start heading back to the lodge. Dinner was delicious as always, and we ended the day with a lecture on the sensory biology of sharks and rays.

Day 5

The day started like the others, but the forecast called for wind. So, we set out to tag sharks in an area where we would have some protection. And it appeared that the nurse sharks were seeking a similar habitat.

Our gear went in the water at 8:15, and by 8:25 we had our first shark – a 7-foot mature male nurse shark. We quickly measured, tagged, and collected tissue samples before releasing him. This was the beginning of a very busy morning full of nurse sharks.

From 10:10 am to 1:30 pm, we caught, tagged, and released over 10 more nurse sharks in the wind-protected waters of Andros’ flats. The sharks were a mixture of male and females. They were all mature and 6-8 feet in length. The team worked quickly and efficiently to ensure the sharks were measured and tagged quickly and safely before being released.

It was a busy 2.5 hours, but very rewarding to get to see and tag so many animals in such a short time. The action calmed down after the tide switch, but we caught and tagged one more nurse shark, plus a blacknose, totaling 33 for the trip!

We picked up our gear, headed home, and enjoyed our dinner before discussing the plan for tomorrow. Rather than using our drumline gear to tag sharks on the east side of Andros, we were going to head west in search of a critically endangered species.

Day 6

The mission for our last full day was ambitious – we hoped to find and tag a smalltooth sawfish. This species was overharvested across much of its range, and today they are very rare. This coupled with their elusive behavior and excellent camouflage would make this a difficult task, but we were up for the challenge.

We hopped on three flats boats with local fishing guides, and headed to West Side National Park – the part of the island we first flew over on our way here at the beginning of the week. Smalltooth sawfish tend to spend their time on the bottom of shallow, shoreline waters where they will wait for schools of fish to swim by that they can use their rostrum to disable before feeding on them. The boat we use for shark tagging unfortunately can’t operate in these shallow waters, but the flats boats we were on today could. In inches of water the captains of these boats took us all over the west side where we saw large schools of bonefish, dozens of sea turtles, many lemon sharks and bonnetheads, dolphins, nurse sharks mating, and flamingos.

We searched for a sawfish for hours, but unfortunately, they eluded us. While sawfish sit on the bottom for long stretches of time, but they will also travel far between feeding areas. It’s hard to know if there were any in the area that we had just missed, or if they were in a different part of Andros that day. Regardless, it was an exciting day filled with lots of wildlife, and leaves a task for the next group to complete.

We arrived back to the lodge and collected and cleaned all of the research gear so that it could be stored until the next trip in July. We enjoyed our final dinner of the trip, then headed off to bed.

Day 7

Our final morning was an exciting one. While we didn’t tag any sharks, we did spend some time with them. After breakfast, we headed over to Isla’s Spot to hang out with 15 lemons sharks ranging from newborns to large adults. We spent a couple hours with them, enjoying watching them swim around in knee- and ankle-deep water.

We would have spent more time there, but we had a plane to catch. We ate our lunch when we returned to the lodge, packed our things, then headed to the airport for our flight home. It was a fantastic experience, and some of us will surely be back again.

Thank you

Thank you to our research trip leaders Dr. Phil Matich and Sorantaa Bain for guiding the team through an incredibly successful week. A huge thank you to our research assistants for their passion, determination and endless enthusiasm to work hard, learn and produce results. We would also like to thank the Andros Island Bonefish Club for their hospitality, and the hardworking and ever professional Stevano for his top class boating and captaining skills.

Gratitude must also go to all on the trip for their generosity in allowing us to use their images in this blog.