blacktip shark – Shark Research & Conservation Program (SRC)

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Shark tagging with Firebrand Events

March 31, 2016/0 Comments/in Shark Research /by aanstett

By Julia Whidden, SRC Intern

On Monday, March 14^th, the SRC Crew went to sea with assistance from Firebrand events. We fished the shallow waters (~ 10 feet deep) of Safety Valve, an area of sand flats and tidal channels that connect Biscayne Bay to the Atlantic Ocean. Research dates the formation of this bay to between 5,000 and 2,400 years ago, while it was only “discovered” to European forces by the Spanish explorer Juan Ponce de Léon in 1513. It was around this time that explorers and fishers of the sea began to record their varied superstitions. Their expeditions were plagued by many sources, including – but not limited to: garlic, actual plagues, the number 13, and bananas.

An aerial photo of Safety Valve, the region of shallow sand flats and tidal channels that delimit the entrance of the Atlantic Ocean to Biscayne Bay. The SRC team fishes this spot often.

While the choppy water kept us from the high seas, and our fishing was for research purposes and not sustenance, we managed to fall victim to the old sailor’s curse of the bananas. Believe it or not, SRC and Diver’s Paradise boat Captains strictly enforce the “NO BANANAS” rule. Not only are they forbidden in the contract that our passengers sign, but even mention of them by SRC grad student and banana-enthusiast Pat Goebel is usually enough to get the team riled up. On this fateful Monday, SRC crew discovered – after pulling up the first set of 10 lines empty – that each of the nearly 20 Firebrand passengers had been packed lunches with… (cue dramatic music)… bananas. Diver’s Paradise Captain Eric Cartaya took matters into his own hands and collected the remaining evil fruit from a very confused set of passengers. The bananas were piled on the bait-cutting table, smashed to bits, and swiftly tossed out to sea. The passengers remained confused. After explaining to them some of the varied and nonsensical origin stories of the banana curse, we had made it back to buoy 1 of the second set of lines.

Diver’s Paradise Captain Eric Cartaya rids our boat of the evil bananas.

Lo and behold, our luck changed and we caught a 1.52 m blacktip shark! This male blacktip was very freshly caught, having only been on the line for 8 minutes. We conducted a full work-up with assistance from our Firebrand crew, including measuring, tagging, fin clipping, and reflex testing. After releasing this blacktip in great condition, we sped off towards our next buoy.

SRC crew Robbie Roemer and Julia Whidden release our first catch of the day, a male blacktip shark.

We pulled up another 8 empty lines before feeling any tension on our last line of the second set. This time, we had caught a 2.3 m male nurse shark. The most interesting characteristic of this male nurse was its recently mated claspers. Claspers are the external sexual organs of male elasmobranchs (sharks, skates and rays), and have friendly features such as hooks and barbs that are used to hold onto the female during copulation. Males may only copulate successfully with a female once it has reached sexual maturity, which is physically manifested as fully calcified (hardened) claspers. In male nurse sharks, sexual maturity is reached when the total body length is around 2.1 m. This male nurse shark that we processed showed signs of having recently copulated, which appear as fresh mating scars on the male’s claspers. This type of sexual maturity data is useful in identifying the breeding requirements, including seasonality and habitat preferences, of local shark populations. After finishing the workup, the SRC team released the nurse shark in great condition.

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The mating scars seen on our second catch of the day, a male nurse shark.

Our final 10 lines of the day proved fruitless, but the SRC crew and Firebrand passengers felt lucky to have caught even 2 sharks considering the bad luck that started their day. While it’s difficult to know precisely which life lessons were learned by passengers and crew of the boat, ie. don’t get between a boat Captain and a banana, I personally took this opportunity to learn “The Bananas Aboard Repentance Prayer,” in case I ever need to appeel to the shark gods again.

The Bananas Aboard Repentance Prayer

Oh great Konpira
please, hear my plea
I am sorry for my mistake
A banana I brought to sea

it was an honest gesture
a noble means of nutrition
I had no ill intent
I brought fruit of my own volition

Please forgive my idiocy
I meant my friends no harm
We just want to go fishing
and go home with a sore arm

We beg of you to release the curse
upon which I have brought
In your honor I consume these bananas
a sacrifice all for nought!

Sources:
http://miamifishing.com/bananas-and-fishing-boats
http://www.discoverbiscaynebay.org/history-and-ecology.htm
https://upload.wikimedia.org/wikipedia/commons/6/6f/Biscayne_Bay_Safety_Valve.png

Shark Tagging with Hialeah High School

December 23, 2015/0 Comments/in Shark Research /by aanstett

By Casey Dresbach, SRC Intern

On the fairly windy and overcast morning of December 3^rd, the SRC team and honorary audience members set sail on yet another successful venture. The SRC team and I met at Crandon Park at 8 AM, along with high school students from Hialeah High School, and a very special guest, a Canadian documentary filmmaker. As we boarded the boat, the skies began to clear up and ensured a day filled with adventure.

Catherine Macdonald, the trip leader for the day, and Jake Jerome, my fellow intern, began to speak to the students about our fishing methods and why we use such specific gear. The two briefed the students on why SRC does what we do and how each and every one of them were about to help in collecting crucial data which impacts both shark research and management. While the explanation took place, I, along with the rest of the team began to set up the gear, bait the hooks, and deploy the drums. This was repeated three times, a total of 30 deployed drums for the day. After the first set of ten, we held tight to let the bait soak in the water for about an hour. Upon waiting, I got to speak with a couple of the students and their very enthusiastic teacher. For some students, it was their first time seeing sharks, let alone being aboard a boat! Having such an avid educator on board made all the difference; the energy was wonderful and not only did the team respond, but the sharks were pretty responsive too! Our first cartilaginous friend hooked onto line four to join our educational soirée. The beautiful male Black Tip came aboard at around 170 cm, about five and a half feet long. To avoid setting up the platform in such rough seas, we landed the shark onto the boat. Little did we know that this little guy would foreshadow the rest of our catches… all to whom were in fact Black Tips! I’m honored to say I took part in such a remarkable set of catches! Teams of four students were set up and each one got to take part in the four primal procedures: nictitating the eye membrane, measuring the shark, taking a fin clip sample, and of course, tagging the shark.

A student conducts a reflex test on the shark’s eye with a stream of ocean water, checking for its ‘eyelid’ called a nictitating membrane. This reflex is being tested as a possible measure of stress levels.

The rest of the day seemed to go by fairly quick; five more sharks were caught throughout the next several hours. We landed a male Black Tip at 157 centimeters (a little over five feet), followed by a male Black Tip at 159 centimeters (a little over five feet), yet another male at 170 centimeters (about five and a half feet), and two female: one with a total length of 170 cm and another at 173 centimeters (almost 6 feet!). The team aided the participants in their tasks, snapped photos of each to get accurate measurements to scale, and drew blood from each shark, which that was taken to the back of the boat and examined by my fellow intern, Stephen Cain. Eager students head back to join him and soak in his masterly shark blood handling. Catch after catch I was able to see the spark in each and every one of the students. In being apart of such an incredible Shark Research Program, I have learned to appreciate the most satisfying recognition: inspiring high school students to take in new knowledge.

A student assists intern, Casey Dresbach, with measurements of the shark.

Honorary Hialeah High School’s biology teacher helps pull in a line, with Blacktip hooked on!

Overall, we had an extraordinary day on the sea with Hialeah High School and the Canadian documentary team, in spite of the choppy waters. After catching a record six Black Tips, I can only presume that everyone on board left feeling satisfied and content with the day. The SRC team was able to gain valuable data from our catches and workups. The trip was made best because of the enthusiasm instilled in all of the students, thank you for your hard work and energy! We only hope you continue to instill your passion in the future; it truly is remarkable. Hope to you again soon!

Shark Tagging with MAST Academy

November 30, 2015/0 Comments/in Shark Research /by aanstett

By Grace Roskar, SRC Intern

On the overcast morning of November 15^th, the SRC team, the Diver’s Paradise captain and crew, and students of MAST Academy gathered at Crandon Marina to brave wind, clouds, and light rain to embark on a day of shark tagging. MAST Academy is one of our oldest participating school groups and although the weather was not the typical Miami sunshine, the students were eager to board the boat and get underway. We motored out through choppy waters to the Safety Valve in Biscayne Bay, which is a group of shallow sand flats that is intersected by the tides flowing in and out. After some quick introductions and a briefing on the process of deploying drumlines, the equipment was set out and allowed to soak for an hour. In the meantime, trip leader Christian Pankow demonstrated the process of working up the sharks to the MAST students. When an hour had passed, we set out to retrieve the first set of ten drumlines. To no avail, there were not any sharks on the first ten lines, so they were set back in the water after being reloaded with fresh pieces of bait. However, several of the hooks came up with the chunk of barracuda steak missing and two lines had bite marks and shredding on the tough monofilament line, so it seemed that sharks could be somewhere close. The second set of ten drumlines was pulled up and again, no sharks. They were set back into the water and were allowed to soak a little bit longer.

A MAST Academy student tosses the barracuda bait into the water.

On the 21^st line, a blacktip had been hooked! To avoid setting up the platform in such rough seas, the 1.64 meter male shark was brought directly onto the stern of the boat by Christian and grad student Robbie. Once secured, MAST students assisted the SRC team with several length measurements, taking a sample of the dorsal fin, and inserting a dart tag into the shark’s dorsal fin. The shark was swiftly released back into the water in great condition. Since time allowed, a fourth set of drumlines was deployed, bringing our total to 40 drumlines for the day. Another blacktip, slightly smaller at 1.53 meters, was pulled up and worked up via the same process on the back of the boat. Students were able to assist in the work-up process again and also touch the shark, feeling the unique texture of their dermal denticles. Another line later had a nurse shark on the hook, but just as Christian and Robbie were pulling it up to secure it onto the boat, it simply spit the hook out of its mouth and swam off! Although it was disappointing to be so close to pulling in our third shark of the day, Christian was able to estimate it at 1.5 meters in length and the students were glad to still be able to see the day’s second shark species at the surface of the water.

A student helps test the reflex of the shark’s ‘eyelid,’ or nictitating membrane, to measure the shark’s stress level.

A student helps measure the total length of the shark.

For the remainder of the trip, Christian dissected a barracuda eye as a demonstration for the students, and the SRC fish traps that had been deployed at the beginning of the trip were pulled up. The fish in the traps, including two filefish, were measured and photographed for the SRC’s ongoing study of fish populations associated with shark populations in the area. Although the weather was a bit less pleasant than we’re used to, it was still a great day out on the water with MAST Academy. For some students, it was their first time seeing sharks, and the whole group seemed pleased and more knowledgeable about these important apex predators after the day was over. The SRC team was able to gain valuable data from the two blacktip sharks and we hope to have MAST Academy back out with us soon!

Thank you MAST Academy for joining us for a day of shark tagging!

Shark Tagging with Our Lady of Lourdes Acadamy

November 12, 2015/0 Comments/in Shark Research /by aanstett

By Christopher Brown, RJD Intern

As dawn broke on Saturday, November 7, 2015, eight sharky RSMAS students and one fearless lab manager awoke to the call of the sea. The RJD team assembled at Diver’s Paradise in Crandon Marina at 8:00am to begin loading the boat with the shark-friendly fishing gear that is utilized to conduct tagging and sampling procedures. Everyone was in a great mood because the forecast for the day called for perfect fishing weather. Once the high school students from Our Lady of Lourdes Academy arrived, brief introductions were made, and the crew set out for an eventful day of shark tagging!

As Captain Nick Perni set course for fishing grounds south of Key Biscayne, and the RJD crewmembers cut bait and prepared the drumlines for deployment, lab manager Christian Pankow briefed the high school group on how the fishing equipment is deployed and retrieved throughout an entire day of fieldwork. Even though Our Lady of Lourdes Academy are old hands at tagging and sampling procedures, they were surprised to learn that fish traps are now being utilized by the RJD team to investigate fish morphologies and population assemblages associated with the presence or absence of shark populations. The two fish traps were deployed south of Stiltsville, a group of wood stilt houses positioned on the edge of Biscayne Bay along the sand banks of the Safety Valve. Then, after watching RJD Intern Samantha Owen demonstrate how to safely and properly cast out the baited circle hook and line, Our Lady of Lourdes Academy students helped deploy the remaining nine drumlines.

While the lines “soaked” for an hour, the students assisted with taking environmental measurements, including the salinity and dissolved oxygen content of the surrounding ocean water. Lab manager Christian Pankow gave another briefing to Our Lady of Lourdes Academy to prepare them for the participatory day of shark research, which would include fin clips, measuring, and collecting vital tissue samples and data. However, the briefing was cut short when a blacktip shark was spotted breaching around the first research buoy, which meant a shark was on the line! The first group of students assembled to assist with data collection as the RJD team sprung into action. The 1.46 meter (4.79 ft) blacktip shark, which was one of the smallest sharks of the day, was swiftly and carefully secured onto the stern of the boat and the water pumped was inserted into the shark’s mouth. RJD graduate student Jake Jerome collected a blood sample from the caudal vein and Our Lady of Lourdes Academy students assisted with taking morphological measurements and inserting a dart tag into the shark’s dorsal fin. After completing a successful workup, the blacktip shark was released back into the water in great condition. The breaching blacktip shark was an amazing sight to see and was only the beginning of a fantastic day of shark tagging.

The largest shark of the day was a 2.00 meter (6.56 ft) great hammerhead that was caught while pulling in the second round of drumlines. Great hammerhead sharks are easily stressed and become quite delicate when kept on the line for an extended period of time, so the students watched from the top deck as the RJD team worked up the shark in less than four minutes. RJD graduate student Jake Jerome was able to collect a blood sample from the caudal vein of the great hammerhead for his ongoing Masters’ research, and the crew worked efficiently enough to conduct an entire workup procedure before the great hammerhead needed to be returned to the water.

In total, the RJD team landed a 2.00 meter (6.56 ft) great hammerhead shark, a 1.67 meter (5.47 ft) nurse shark, a 1.25 meter (4.10 ft) black nose shark, and six blacktip sharks ranging from 1.18-1.71 meters (3.87-5.61 ft). Each shark was swiftly and carefully brought to the boat and secured on the platform for a brief sampling and tagging procedure. It is safe to say that Our Lady of Lourdes Academy students are now well practiced in tagging, sampling, and morphological measurement techniques. One of the procedures performed by the students included the nictitating membrane reflex test. The nictitating membrane is a clear, inner eyelid that protects the eye of a shark during feeding events. The reflex of the nictitating membrane is one visual factor that can be used to determine the stress impairment of sharks.

After the remaining drumlines were brought on board, the crew finished the day by checking the fish traps set earlier in the morning. A series of morphological measurements and images was taken of each of the several bony fish caught in the fish traps for future analysis. Overall, the RJD team had a fantastic day out on the water with Our Lady of Lourdes Academy. We hope they enjoyed the opportunity to participate in a day filled with exceptional scientific research and education, and we cannot wait for them to join us again on future shark tagging trips.

Shark Tagging With Palmer Trinity High School

November 11, 2015/0 Comments/in Shark Research /by aanstett

By Melissa Soto, RJD Intern

It was a warm November morning as the students from Palmer Trinity high school made their way onto the boat. This was my first trip of the semester so I was just as eager as they were to see sharks. After placing all the gear onto the boat, RJD and our guests were off to tag some sharks.

A Palmer Trinity student kissing the bait for luck.

Our trip leader for the day was Christian Pankow, who kindly greeted everyone on board and continued by explaining the work up the team does on the sharks. After a calm thirty-minute boat ride we started deploying the 10 drumlines around Stiltsville, off of Key Biscayne.

A student carefully released a drumline into the water.

After waiting an hour, we started to check the drumlines and after a three tries, we found ourselves a shark. A female black tip was safely worked up on the platform. The students broke up into groups of five and began the work up consisting of fin clip, tagging, measuring and two nictitating membrane tests. This beautiful shark was 1.65 meters and healthy. Once the work up was completed, the shark was released.

Students and the RJD crew quickly work up the blacktip.

We continued to check and redeploy the drumlines but they were no sharks. Our second and third sets of deployments were a success. Three more black tips with lengths of 1.67 meters, 1.58 meters, 1.62 meters and a 2.35-meter nurse shark were pulled up. These four female sharks were worked up with the help of the students and RJD.

Another bait kiss for luck.

After pulling up the rest of the drumlines we made our way back to marina and took some group photos. Palmer Trinity was a great group of enthusiastic children and chaperones. We hope that they come out for another trip soon.

Shark Tagging with Christopher Columbus High School

October 30, 2015/0 Comments/in Shark Research /by aanstett

By Shannon Moorhead, RJD Intern

The sun was just beginning to rise as my fellow intern, Grace Roskar, and I began our drive to Crandon Marina. On a typical day, waking up so early would leave me tired and irritable, but it’s hard not to be in a good mood when you have a day of shark tagging to look forward to. We met with the rest of the RJD team at 8, loaded up Diver’s Paradise with the equipment we’d need for the day, and, once our school group was ready, set out to tag some sharks!

As the team cut bait and prepared the drumlines for deployment, our trip leader Pat Goebel briefed the students on our fishing gear and how they would be assisting in our research. This trip we were joined by Christopher Columbus High School, and they were the most energetic group I’d seen yet! The boys divided themselves into four teams (which they dubbed Banana, Nemo, Clasper, and Pumpkin Spice) to take turns participating in such critical tasks as taking a fin clipping, measuring, and, most importantly, tagging the sharks. After the short trip to Stiltsville, a community of houses built on stilts above the waters of Biscayne Bay and our site for the day, the team set two fish traps. These wire mesh cages are baited to attract nearby fish and give us insight as to what species the sharks are sharing a habitat with. Then, students helped us deploy the first set of 10 drumlines; spirits were high as each line set was met with a round of cheers and applause from the enthusiastic Christopher Columbus High.

With the help of the RJD team, a Christopher Columbus student measures a blacktip shark.

After the students assisted us with some environmental measurements and the lines had soaked for an hour, we returned to the first drum. When a Christopher Columbus student hauled the drum onto the boat, it was apparent we were sharkless for now. However, we didn’t have to wait long. Team Banana, proving the fruit may not be bad luck on boats after all, suggested the use of a banana-colored yo-yo (plastic ring monofilament is wrapped around)to pull in the line on drum #4 and sure enough, there was a shark on! The smallest shark of the day, measuring 1.5 meters (a little over 5 feet), the male blacktip fought hard, running all over the place before we got him on the boat. Once the shark was secured on the platform, Christopher Columbus students assisted the team with data collection while graduate interns drew blood and took morphological measurements. The whole process was done in about five minutes and the blacktip swam off in great condition!

Trip leader Pat Goebel and graduate intern Julia Whidden affix a satellite tag to the dorsal of a huge female bull shark.

There were no sharks to be found on the remaining lines of the first set, but hopes were still high. The boys of Christopher Columbus High kept up the energy by singing, treating the team to rousing renditions of tunes ranging from “Bennie and the Jets” to “Hotline Bling”. “I’ve never met a group of high school boys that likes to sing acapella more” said graduate intern Julia Whidden. Apparently, the sharks enjoyed the music because on the fourth drum of the second set we had another shark; this time it was a massive female bull shark, 2.7 meters (almost 9 feet) long! She was enormous, there was barely enough room for the team on the platform with her. While the RJD team and Christopher Columbus students performed the usual workup, a satellite tag, generously provided by citizen scientist Nika Hosseini, was attached to the shark’s dorsal fin. Satellite tagging a new shark is very exciting because it provides us with data that can help answer important questions about shark movement patterns, habitat preference, and vulnerability.

Undergraduate intern Grace Roskar helps a Christopher Columbus student apply a dart tag to a bull shark.

We stayed very busy the rest of the day, catching a total of 7 sharks! We landed a 1.9 meter (6.5 ft) feisty female nurse shark, a small 1.8 meter (6.2 ft) male bull, and three female blacktips, ranging from 1.6-1.7 meters (5.2-5.7 ft). Once the last drumline was hauled in, we made our way back to the fish traps. The team measured and photographed the fish caught, primarily pinfish, and returned them to the ocean while the boat headed back to the marina. This was a great trip; not only did we gain data on several sharks of three species, but we got to deploy a new satellite tag that will gain valuable data on the movement of the bull shark. The day was made even better by the fantastic attitudes of the students of Christopher Columbus High. Thank you for your hard work and enthusiasm, hope to see you on the boat again soon!

Christopher Columbus High School students and faculty, our citizen scientists, and the RJD team after a long, busy day.

Shark Tagging with Pine Crest School

October 20, 2015/0 Comments/in Shark Research /by aanstett

By William Evans, RJD Intern

I woke up on Thursday morning and saw that it was slightly overcast and drizzling. For more people, this would be a sign of a gloomy day inside but for me and the rest of the RJD crew, it was the perfect set up for a day of shark tagging. The crew met at Crandon Park at 8 AM, along with high school students from Pine Crest School in Fort Lauderdale. As we boarded the boat, reviewed some boat safety and pulled out from the marina, the skies began to clear up and the sun was shining.

Our trip leader for the day, Christian Pankow, began to speak to the students about our fishing methods and why we use the specific gear that we do. While Christian was talking, the rest of the team began to set up the gear, bait the hooks, and deploy the drums. After the 10^th drum was deployed, we waited to let the bait soak in the water and allow time for sharks to get on the hooks. While we were waiting, Shannon Moorhead, an undergraduate student at UM, and I saw a blacktip breach on the 6^th drum! We knew it was a good sign for how the rest of the day was going to go. Because of our sighting, we went to the 6^th drum first and sure enough, there was a blacktip shark on the line. That was only 1 of 4 blacktips from that days trip. Of the four, the last blacktip that we pulled in was 1.92 meters, slightly over 6 feet, which Christian said was the “first or second largest blacktip” that he’s ever seen!

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A closeup image of a blacktip eye and ampullae of lorenzini.

The Pine Crest students were able to interact with each shark by assisting the team in collecting data. The student tasks were checking the presence of the nictitating membrane on the eye with a squirt of water, measuring the shark, taking a fin clip, and tagging the shark. These opportunities allow students to not only interact with sharks but to participate in meaningful research and will hopefully light a spark in them to pursue science or at least be more knowledgeable about sharks importance to the ocean ecosystem. It was also beneficial to the students to be able to witness another graduate student, Robbie Roemer, be able to collect blood samples from all of the blacktip sharks.

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The RJD team secures the shark as graduate intern, Hannah Calich, assists a Pine Crest student in tagging the blacktip shark.

Towards the end of the day, we also caught a small, adult blacknose shark in addition to the 4 blacktips that we caught before. Because of its size, it was placed on the deck for the work up and the students on board were able to get a chance to see the differences between the blacktips we caught before and this new species. We made it back to the dock to unload and clean the gear for the next trip going out the following day. Aside from all of the sharks, not having to remove the drums from the boat was my favorite part of the day! Although it was an exhausting day, that was the most amount of blacktips that I have personally seen on a trip and even though they are not my favorite shark, they are still beautiful animals. Every tagging trip makes me more excited than the next because I come on the boat more equipped with knowledge than the time before!

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Trip Leader, Christian Pankow, and undergraduate intern, Casey Dresbach, secure this blacknose shark as graduate intern, Robbie Roemer, draws blood for analysis.

Shark Tagging with Westminster Christian School

October 14, 2015/0 Comments/in Shark Research /by aanstett

By Hannah Calich, RJD Graduate Student

Last Friday the RJD team was joined by the fabulous students and teachers from Westminster Christian School for another day of shark tagging!

The Westminster students, teachers, and the RJD team after a great day on the water

The RJD team met at Crandon Marina at 8 am to begin loading up Divers Paradise. Despite the hurricane over the Bahamas, Miami’s coastal waters were calm and the weather was great, so we were eager to get out on the water. Once everyone was on the boat the RJD team introduced themselves, our trip leader, Emily Nelson gave everyone a briefing, and we set off!

Once we got to the site, the RJD team deployed a baited fish trap as part of a new project we’re working on to learn more about the fish communities at our tagging sites. Once the trap was deployed we set 10 drumlines, took some environmental data, and had some lunch while we let the lines soak. After the hour-long soak we began checking our lines. Our first line came up empty, but when we got to drum # 2 we felt a familiar tug on the line and everyone sprang into action. Our first shark of the day was a 171 cm male blacktip shark!

A Westminster student gives the bait a kiss for good luck!

Once we tagged and released him we headed over to drum # 3 where once again we felt a familiar tug on the line. Our second shark of the day was a 174 cm female blacktip shark! What was particularly interesting about this girl was that she was a recapture! We checked our records and determined that we originally tagged her back on November 1^st, 2013! Back in 2013 she was 169 cm and has grown to 174 cm since then. We get really excited about recaptures because they are relatively rare and give us a lot of interesting data about how these animals are growing, where they are living, and what they are eating!

A Westminster student helping collect a fin clip from one of the blacktips

Once we re-tagged and released her we went to drum # 4, where once again there was a shark on the line! On drum # 4 we caught another 174 cm female blacktip! She had only been on the line for a few minutes so we decided to surgically implant an acoustic tag in her abdomen as part of our Urban Shark Project, which is studying how sharks use highly urbanized environments.

Once she was tagged and released we went back to checking and rebaiting our lines. Unfortunately, the next 16 lines came up empty. However, something was clearly eating our bait and since the first few lines had been so busy we knew it was only a matter of time until we caught another shark, so we decided to set 5 more lines.

While we were waiting for those lines to soak we decided to pull up our fish trap and work-up the fish we caught. We ended up catching about 25 fish from approximately 6 species! Once the fish trap was back on the boat we went to check on our drumlines and found that we’d caught one last shark! This time we had caught a large (240 cm) male nurse shark! The RJD team secured him while the students went to work collecting data. Within a few minutes the workup was complete and he was on his way again.

RJD intern Julia Whidden takes measurements of a fish caught in our fish trap

In the end it was a very successful day because we caught 4 sharks! We caught 3 similarly sized blacktips (one of which was a recapture!) and a large male nurse shark. In addition to doing our usual work-up we also deployed an acoustic tag and gained new data on the local fish communities! Thanks again for all your hard work Westminster, it is always a pleasure to go out with you guys. I can’t wait until the next trip!

Our last shark of the day, a 240 cm male nurse shark!

Shark Tagging With Steve Brodie Charter

September 28, 2015/0 Comments/in Shark Research /by aanstett

By Alison Enchelmaier, RJD Intern

Friday morning couldn’t come fast enough. It felt like forever since I had been on a tagging trip and I was chomping at the bit to get started. The crew arrived an hour early to load gear and everyone seemed to be in a genial mood as we hauled drumlines and bait. Today our new intern, Julia Whidden, was joining us for her first trip! Just as we were loading up, we were joined by our group of UM citizen scientists.

Dr. Neil Hammerschlag explaining RJD’s shark workup procedure

We headed out to Stiltsville, a series of stilt houses that reside offshore in Biscayne Bay, and began to set our gear. We added a new procedure to our protocol on this trip, fish traps. Our fish traps are large, square, portable structures made of mesh meant to catch fish without a rod and reel. We use these traps to see what fish live in the areas where we catch sharks. We placed two fish traps into the water and let them soak while we fished for sharks. After the traps were released, we set our drumlines into the water and let them soak. While we waited, Dr. Hammerschlag explained the importance of shark research and conservation and our citizen scientists learned about the tasks they would be participating in on the trip.

The RJD crew sets up gear

After an hour, we returned to check on our lines. Early in the day, we don’t often get a shark on the first line so imagine our surprise when we caught a shark on our first line, and it was a blacknose to boot! Most blacknose sharks are small; adults can grow to about 4 ft long. We don’t catch them often, so this find was a real treat! There was no time to spare as we had another shark on the second line, this time a 172 cm (~5.6 ft) female blacktip. Our citizen scientists helped the team measure, gather blood and fin samples, and tag the shark before releasing her back into the water. The next shark we encountered was another blacktip, female as well at 163 cm (~5.3 ft).

Citizen scientist checks the reflexes of a blacktip shark by squirting water in its eye.

As we pulled in the last line the sound of thunder indicated it was time to head back to shore. On the way back to the dock, we retrieved the fish traps and identified the fish we caught. Between both traps there were five fish in total and three different species of bony fish. The species we caught were planehead filefish, a saucereye porgy, and two lane snappers.

All in all, it was a wonderful day! Thank you to our citizen scientists for joining us on a great trip!

Shark tagging with Empowered Youth

May 14, 2015/1 Comment/in Shark Research /by aanstett

by Alison Enchelmeier, RJD student

On Saturday morning I headed over to Crandon Marina. As I drove down the causeway, the weather promised a great day with not a cloud in the sky. Our guests for the day were a brand new group, Empowered Youth, and several family members of graduating interns. With our gear loaded onto the boat and everyone excited for tagging we headed out to the Belzona wreck.

On the trip out, Jake explained what we would be doing and how our guests would be helping us with our research. We set our lines east of the wreck. Initially, some of our guests were a bit shy, but with a little encouragement they were soon pulling lines alongside us.

A student pulls in a drumline to check for a shark

After letting the lines soak for an hour, we returned to pull lines. Early on in the day we caught our first shark. As line 3 was pulled up, something tugged on the line. With a shout of “Shark on!” the boat became a flurry of activity as the RJD team prepared to bring the shark to the boat. As the line was pulled in we predicted what we caught, the consensus being a nurse shark. We were pleasantly surprised when a 204 cm (~6.6 ft) sandbar shark came to the surface.

The students were prepared as they helped us work up the shark, bursting with excitement as they got to feel the sandpaper like skin of the shark and take measurements. Any fear of the shark disappeared as the shark remained calm during the whole procedure. Moments like these just highlight how important it is to give people first hand experience with sharks to help dispel the stigma against them. After the quick workup the shark was released, swimming down into the ocean until we could no longer see it. The first shark set the tone for the day as our guest’s infectious enthusiasm grew.

RJD intern Hanover draws blood from a shark’s caudal vein

More sharks were soon to follow as we caught four more sharks, all in the same set. Our second shark was a nurse, followed by a blacktip. At only 126 cm (~4.1ft) it was one of the smallest sharks I’d seen while working on the boat! After that we caught two more nurse sharks. One popped off the hook just before we managed to get it onto the platform while the last nurse was a whopping 258 cm (~8.4 feet)! We continued to pull and set 20 more lines but we didn’t catch any more sharks that day. Even so, our guests remained enthusiastic, asking questions and pulling up drumlines like pros. While we caught no more sharks on our drumlines we managed to see a sea turtle resting at the surface.

An unexpected treat, a sea turtle!

In all this was a great trip with a wonderful group. Thank you to Empowered Youth for being such a great group and good luck to our graduating interns!