Expedition leaders: Dr. Tristan Guttridge and Dr. Phil Matich

Crew: Angell, Austin, Betsy, Brianna, Lauren, and Molli

Introduction

A great hammerhead, a juvenile tiger shark, Caribbean reef sharks, silkies and more, sharks dominated our week and we loved every minute! We also deployed our first ever deep water receiver, fished new locations, and hopped in the ocean for some dives. Our week was loaded with adventure; read all about it in our blog below.

Day 1

With growing anticipation, today marked the beginning of Saving the Blue’s third trip this year with hopes of tagging sharks, deploying tracking equipment, and exploring the diversity of habitats across Andros. Everyone met at our meeting point, a semi-private airport, and after introductions and checking in, we boarded our charter flight and were off to Andros. After just 45 minutes, the west side of Andros came into view – a colorful mosaic of shallow shorelines and tidal creeks that provided a glimpse into the array of habitats across the island. Fifteen minutes later, after flying over numerous blue holes for which Andros is famous for, we landed in Fresh Creek, cleared immigration and customs, and took a short taxi ride to the Andros Island Bonefish Club – our home for the next week.

Excitement was apparent across each trip member as we checked in amidst a backdrop of mangrove shorelines, nearby seagrass beds and coral reef. Everyone found their rooms and unpacked, then settled in for a briefing, including the research plan for the week, expectations of guests and Saving the Blue personnel, and a safety overview to ensure everyone was prepared for their time in and on the water. Prior to making our way out for our first afternoon of research the team prepared the fishing gear used to sample the sharks we would tag during the trip. In addition they prepared materials for deploying an acoustic receiver in 1100 meters of water in the open ocean. This receiver would be used to track the residency and co-occurrence patterns of silky sharks tagged with acoustic transmitters, providing insight into their biology, ecology, and risks associated with human actions like fishing.

Finally, with a few hours remaining before sunset, the team headed to a nearby seagrass and patch reef habitat for some drumline fishing to gain practice for the week, and to see if we could tag any nearby sharks. We were in luck! Two Caribbean reef sharks were on our lines within a short time period, including a 7ft female that would be the largest reef shark tagged this trip. Everyone was excited for the hands on experience, and the afternoon left an even greater feeling of anticipation as to what the week had in store. As the sun dropped close to the horizon, the team hauled our gear, and returned to the lodge to clean up and sit down for a delicious lobster dinner, with a slice of cheesecake for dessert. Despite only a short time on the water, it was a successful day, and tomorrow would bring challenge and excitement as we planned to venture out to the deep blue waters of the Tongue of the Ocean.

Day 2

We woke up with the stars still shining and the sun yet to make an appearance in order to get an early start to the day. After enjoying a made-to-order breakfast and packing our lunches, we loaded gear on to the boat and headed out to our first destination of the day – the Tongue of the Ocean. The windy weather slowed us down, taking a little longer than normal to get to our sampling site. But after ~30 minutes we arrived safely, and got to work. Before deploying our fishing gear to catch and tag sharks, we endeavored to deploy an acoustic receiver in 1100 meters of cerulean blue water to track the silky sharks we tagged in 2019-2020, in addition to those we will tag in the future; this project will help assess residency and interactions among sharks across size-classes. After ~20 minutes of unspooling the line we prepped yesterday, and attaching a few pieces of equipment, the deployment was complete – a great success and newfound anticipation for the coming months of which sharks would be detected – to be continued in 2021…

After meeting this first goal of the day, we immediately set to deploying equipment to catch and tag the silky sharks in the vicinity, with hopes of outfitting them with acoustic transmitters that would be detected by our newly deployed receiver! And it didn’t take long. The first shark was small – only 4ft in length – but feisty once we secured him alongside the boat. After placing both internal and external identification tags, and taking a few measurements, we released him back to the ocean, and prepared the gear for another shark. Soon after casting the line into the water, another shark was on the set, and it wasn’t a juvenile this time. As the line surfaced, a massive 9ft male silky shark emerged from the deep, then showed his power pulling the gear clear out of the boat, and submerging the buoys that marked his location. After a few minutes moving him back to the surface, the team secured, measured, and tagged the shark with internal and external identification tags, as well as surgically equipping him with an acoustic transmitter prior to a successful release.

This was the largest silky shark tagged on a research trip by Saving the Blue, and excitement was building. But in lieu of the strengthening winds, the team headed in shore to have lunch, followed by gathering the drumline equipment for some more tagging in an area known for large sharks, including a 10ft tiger shark that was tagged by Saving the Blue in 2019. To our surprise, the first two sharks caught weren’t giants, but blacknose sharks, around 3ft in length. While small in stature, these sharks can be quite feisty, and are a sign that the area supports a diversity of shark species across a wide size range, a good indicator of ecosystem health. After successfully tagging these blacknose sharks, each swam off strong.

We added one more species to the list before the end of the day – a 9ft nurse shark! Nurse sharks typically sit on the bottom, resting for large portions of the day, so when we catch this species, they often require a bit more persistence to secure and tag them. Similar to yesterday, we hauled our gear as the sun started setting, and headed back for a delicious dinner of pork ribs and locally flavored coleslaw, with discussion about what tomorrow would hold – a trip north to download receivers deployed to track local sawfish, and our first opportunity to sample for our primary target species for this trip – great hammerheads.

Day 3

Based on the tides for the day, we slept a bit later, waking up with the sunrise, enjoying our breakfasts, and packing our lunches before heading out. Despite strong winds, the fringing reef protected us as we traveled an hour north to a beautiful mangrove creek, where we sought out and downloaded data from acoustic receivers that track the movements of tagged sharks and rays in the region. Despite only a few detections, we found that several sharks from different islands across The Bahamas had travelled through the area over the last six months, which was encouraging considering our second objective of the day – set our drumlines to tag the sharks in the area, including what we hoped would be the first hammerhead of the trip.

We found an ideal sampling location between two cays, with a channel connecting fore reef and back reef habitats. After cutting some bait and preparing the gear, we cast our hooks in hopes of catching some large sharks cruising the area. It took some time before our first bite, but once the sharks started to appear, it was a busy day filled with the usual suspects - nurse sharks, blacknose shark, and Caribbean reef sharks. The team worked diligently to secure, tag and measure, and then release each shark in a short time period to ensure the health and safety of each animal. A highlight of the day was a juvenile reef shark just under 3ft in length, one of the smallest Caribbean reef sharks Saving the Blue has tagged since 2019, which we hope to sample in the years to come to assess growth rates and habitat use patterns of this species across the island. Not every shark is a giant, and sometimes the smaller individuals are a treat with more defined coloration patterns that aid in camouflage from predators. 

Because of our long trip back to the lodge, and the windy weather, we headed home a bit earlier than the previous days, unfortunately without encountering the species we had hope for – the great hammerhead. Despite this small let down, the day was another huge success with seven sharks tagged, and as time progressed over the day, comradery among the crew and efficiency with deploying and checking the gear and tagging the sharks increased. After arriving at the dock and unloading the boat, everyone looked forward to the first lecture of the week delivered by Tristan after cleaning up and settling in for the evening.

Day 4

Early mornings may not be everyone’s favorite, but waking up before the sun, and watching it rise across the horizon and set the sky ablaze with pinks, oranges, and purples as you head out from the dock is always a treat, especially when you know you’re heading to a place where great hammerheads have been tagged the previous two Saving the Blue trips. Upon our arrival at our sampling location, everyone was excited about the prospect of encountering a great hammerhead. The area has recently been identified as a hot spot for these sharks, and hopes were high to catch and deploy a smart position and temperature (SPOT) tag on one of these individuals cruising the area. The first hour of sampling started slow – several checks without any action. But the tide started to turn when a 5ft Caribbean reef shark tested our shark handling skills, and got us warmed up for the next shark, which was not a disappointment.

Sharks are highly diverse, and across Andros, species ranging from nurse sharks to lemon sharks and blacktips to tiger sharks all exhibit unique appearances, dispositions, and behaviors. We find a variety of species across multiple habitats, and they all provide distinct experiences when handling and tagging them. But, there are some species that steal the show, and the next shark would do just that. At mid-morning, as the tide continued to move out over the reef, the slight movement of a buoy indicated that something was on the line. At first glance we thought it might be another reef shark, or a blacknose, which we consistently sampled the previous day. However, as we approached and the buoy was retrieved, we realized it was the shark we had planned this trip for – a great hammerhead that we would deploy a SPOT tag on to track its movement over the next six - nine months. As the crew prepared to secure the shark, anticipation grew, and the shark begin to show signs of greater energy as the hammerhead swam twice around the boat! The shark was then quickly secured alongside the boat to ensure its safety and the safety of everyone on board, and the tagging process was underway. With the help of several team members, Tristan quickly secured a SPOT tag to the shark’s dorsal fin, with an antenna designed to transmit coordinates to nearby satellites every time the fin breaks the surface of the water. After quickly taking length measurements, and attaching internal and external ID tags, the shark was released and strongly swam off in the direction of the reef. This individual was later detected the following day miles south of where it was tagged, and subsequently continued traveling south.

Everyone was elated, and hopeful for more sharks considering it wasn’t even 10am. While only two more nurse sharks showed up the rest of the day, the crew was ecstatic from the encounter with the 10ft female hammerhead, and excited about the next day and what it held in store. Tides and wind led to an early return to the lodge, but before completing the return trip, we hopped in the water at a nearby blue hole to explore and enjoy the diversity of fishes, corals, and other invertebrates that these iconic Androsian habitats are home to. After an hour of snorkeling, we made our way to the lodge where the sampling gear was fixed and cleaned. Later, Tristan delivered another lecture, this time on shark research methods including the tag we had just fitted the hammerhead with, and we enjoyed a delicious locally sourced conch dinner before preparing for tomorrows adventures.

Day 5

Strong winds limited our choices for sampling sites today, but no one was disappointed when it was announced that we would return to where we were yesterday, in hopes of another encounter with a hammerhead that we could also outfit with a SPOT tag. The day started out fast and furious with four reef sharks >4ft before 11 o’clock, including a 5ft female. Caribbean reef sharks exhibit swimming speeds and power that rival many other larger shark species around Andros’ reefs, especially once they reach sizes of maturity. While less morphologically distinct than a hammerhead, they are equally exciting to work with. 

Then, another star stole the show. Not another hammerhead as we hoped for, but a 4ft juvenile tiger shark which was missing the upper portion of her tail! The wide mouths and uniquely shaped teeth of this species make it the ideal predator of larger-bodied prey like sea turtles that frequent the sampling area, and help serve as visual identifiers of tiger sharks. But the characteristic stripes of this species are what first stands out, and the coloration of this small female was striking against the turquoise water. Everyone had a chance to work with her, and upon her release, we watched her swim back to the seagrass beds she may have been hunting in before we encountered her on our line. Part of the excitement of Andros is not only the sheer number of sharks its ecosystems support, but also the diversity of species. At this point in the trip, we had tagged or seen seven different species of sharks ranging from <3ft to nearly 10ft, all within the same general area. It always astounds us how productive these waters are, and hammerheads and tiger sharks always provide a surprise despite our realization that they regularly cruise these waters. After tagging the tiger shark, we wrapped up our day on the water with another nurse shark and one of our growing favorites, a blacknose.

Despite the windy weather, the sun had finally fully emerged today, and to cool off, we enjoyed a snorkel in the shallow waters surrounding the cay we fished at, where we found snapper, houndfish, wrasses, and a curious barracuda that kept its eye on us for a few minutes while it passed through. Once back on the boat, we returned to the lodge for another afternoon of gear prep for tomorrow, along with a special treat provided by our boat captain Cole – conch salad – a Bahamian treat from locally sourced ingredients like no other. We relaxed outside the lodge, enjoying the breeze and the setting sun, followed by a sky-full of stars now that the clouds had dispersed. Tomorrow would be our last full day in Andros, and it would not disappoint.

Day 6

After breakfast and preparing the gear for the day, we headed out to a new spot for the trip, also known for its hammerheads. It would be our deepest site for the drumlines, and we hoped that with the predicted tide and clear waters, that our luck would be good once again! - This channel is known for its big sharks that cruise the healthy reef. Earlier in the year Saving the Blue tagged a male hammerhead named Storm in this very site seven months prior, and we were hoping for similar luck today.

The morning was busy, with seven sharks over the first three hours, testing the strength and stamina of the team. Among the sampled sharks, one was a 6ft reef shark that was previously tagged by Saving the Blue in early 2019 in the same spot. Recaptures are always exciting not only because of the incredibly valuable data, but also confirmation that the sharks we’ve tagged are healthy and do not exhibit an adverse response to being sampled. This shark, along with six other Caribbean reef sharks would make this a very busy day for our team. 

To ensure the health of the sharks, our hooks are checked every 45 minutes, and our equipment is viewed and used as an indicator for the presence of a shark on a hook. Despite our relatively short check times, we had at least one shark on every hook check today. The usual suspects – Caribbean reef, blacknose, and nurse sharks filled our day with activity, and we ended the day with 12 sharks in total, which is the second highest for any one day for Saving the Blue in Andros to date. Among the most exciting moments of the day, one of the hooks showed signs of shark action, and upon closer inspection, all three buoys were submerged five separate times in a matter of two minutes – a feat of strength displayed by the shark that was hooked. While the crew were hoping for another hammerhead or tiger shark, the powerful shark was another reef shark just under 7ft in length. After tagging her and another 3ft juvenile reef, we called it a day.

Before heading back to the lodge, we stopped by a nearby back reef, where we hopped in to cool off and do a little exploring. Despite the disparate nature of the reef patches, the area was teeming with life – pufferfish, stingrays, angelfish, and elkhorn corals were but a few of the species found in these shallow waters, which was a wonderful conclusion to our final full day in Andros. Upon returning to the lodge, everyone started to pack up in anticipation of leaving tomorrow, but were able to enjoy one more local dish – conch fritters – provided once again by Cole before another lobster dinner at the lodge. Tomorrow would be our final day on the water, and we hoped for a few more sharks to cap off a very successful trip.

Day 7

On our final day we were met with a treat – the wind had died down over night, and while still a bit bumpy, the drive out to the open ocean was rather calming, and conditions allowed us to hop in the water for a snorkel in 1100 meters of blue water. Upon getting in, we were met by a small school of rainbow runners, who were joined by a couple small silky sharks. While the larger sharks are truly awe-inspiring based on their size and power, juvenile sharks provide a different experience. Despite their small stature, juvenile silky sharks are often much less cautious than the larger sharks, providing the opportunity to interact with these sharks in their world by remaining still and watching their graceful movements up close. The curiosity of these sharks make them a favorite among our team and though only a few showed up, we enjoyed the experience, and then prepared to deploy our equipment for our last fishing set of the trip.

Despite a slower morning than all of our previous days, we tagged two of the sharks we observed while snorkeling, and outfitted them with internal and external tags in hopes to identify these individuals upon the next trip. The close proximity these sharks swim provides the opportunity to note recurring individuals without actually catching them by simply reading off the tag number of these sharks while snorkeling. After reaching our time limit, we headed back knowing that we would be leaving, but very appreciative of the ocean and everyone on the trip for providing yet another unforgettable week. Upon leaving Andros we were given one last gift as we flew over the island, once again enjoying its beautiful landscapes as excitement built over thoughts and discussion of the next trips in early 2021.

Thank you

Thank you to our research trip leaders Dr. Tristan Guttridge and Dr. Phil Matich 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 Cole from PFO Charters 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.

Early results

Blacknose shark - 8

Caribbean Reef - 18

Great Hammerhead shark - 1

Nurse shark - 7

Silky shark - 4

Tiger shark - 1

Total shark count for the week: 39