Category Archives: Neil Hammerschlag

The Summer of Sharks

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The SRC team releasing a nurse shark (Ginglymostoma cirratum) back into the Atlantic Ocean

As I have written here before, I love sharks.

Every size and type of shark intrigues me and the more I encounter these amazing creatures, the more I want to learn. In fact, one of my goals this summer has been to spend at least 30 days aboard research vessels catching, tagging, collecting scientific data on and releasing sharks. I am happy to report that I expect to accomplish or exceed my goal and that my summer of sharks has been incredible.

Thankfully I live in a region of the world that allows me to study these amazing creatures and that’s particularly the case because of my college. I’m fortunate to attend one of the leading marine science schools in the world, the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, and am deeply honored to be part of the small team that makes up Dr. Neil Hammerschlag’s renowned Shark Research and Conversation (SRC) Lab.

From nurse sharks, like the one above, and great hammerheads to black tips and tiger sharks to just about everything in between that you can imagine, we see them all in our work with SRC. In my own work this summer, over the course of almost 30 days in the field on board research vessels, I have been fortunate to have helped catch, study and tag at least 10 different species of sharks through my internship with SRC and as a student of the Field School’s Elasmobranch Course.

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Nurse shark (Ginglymostoma cirratum)

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Nurse shark (Ginglymostoma cirratum)

My summer began with a week-long trip out of Key West where we traveled to the Dry Tortugas and lived aboard the Field School’s Research Vessel Garvin. I was honored to have been selected for the trip and work with the incredible people from the Field School, as well as members of the SRC team so as to study the Tortuga’s Gulf of Mexico shark population.

During our week offshore, not only were we able to dive some exquisite sunken wrecks covered in all sorts of colorful tropical fish species and sea turtles, but we also caught, tagged and collected biological samples on 27 different sharks (8 species total) before gently releasing them back into the wild. The SRC and Field School teams also spent another two weeks in the Dry Tortugas where they caught and released 51 more sharks for a total of 78 over the three weeks of research we performed there in May and June.

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SRC quickly working up a great hammerhead (Sphyrna mokarran)

I then spent another week on the RV Garvin with the Field School staff as we sailed the waters off the coast of Miami out in the Atlantic Ocean. Each day we performed science on the sharks that we caught and released and learned about their role and importance within our natural environment as an apex species. During that week we caught and released some very cool species including bonnethead sharks, blacknose sharks and even a smalltooth sawfish that we quickly released back into the water before reporting our sighting to the U.S. Fish and Wildlife Service as is required due to their highly endangered status. Protecting important species like the sawfish or the great hammerhead is critical to every element of our environment and the news out of Washington, which you can read here, that the Trump Administration wants to reduce those protections is deeply disappointing.

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Drawing blood from a nurse shark (Ginglymostoma cirratum)

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Processing a shark’s blood in the on-board lab to extract plasma

In the event that you are curious about such scientific work, what we do when catching and releasing sharks, I’ve included a few pictures within this blog from this summer. When ‘working up a shark’, as we call it, we carefully and gently secure most of the sharks onto a special platform off the back of the boat (the stern) and in the short time it’s there we quickly collect all sorts of data including measurements, fin clips, muscle biopsies, blood samples and then we tag each shark using either a NOAA tag, acoustic tag or satellite tag.

Some species, such as the majestic and protected Great Hammerhead, never leave the water (I’ve included some pictures of our work this summer on these incredible animals as well) and in every single case great care is taken to respect the animal in every way and to release them as quickly as possible back into their natural environment.  The process is orchestrated like a symphony, a shark science symphony I would could call it, as each member of the team has a specific role for that day’s trip, has gone through extensive training and is supervised at all times by highly knowledgeable leaders with years of hands on field experience.

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Drawing blood from a blacktip shark (Carcharhinus limbatus)

I’ve also, of course, been aboard many trips throughout my first two semesters that SRC has conducted and it was on one of those trips that I have one of my fondest memories of my first year. It was the first time that I had ever been offshore with the team, meaning we were in 100 feet deeper water than usual and had to add extension lines to our gear. It was an amazing day where we caught two bull sharks, two great hammerheads, and one tiger shark. I should mention that it was actually my first time ever seeing a great hammerhead and a tiger shark in person. It was such an exciting (and exhausting day) that I fell asleep as I was telling my family about our adventures and good fortune!

As my Summer of Sharks continues, I want to remind everyone that Dr. Hammerschlag and the University of Miami’s Shark Research & Conservation Lab will be featured in three different Shark Week episodes this summer! Be sure to check out “Monster Tag” Monday July 23rd at 8:00pm, “Shark Tank Meets Shark Week”Wednesday July 25th at 9:00 pm, and “Tiger Shark Invasion” Thursday July 26th at 10:00 pm!

My friends at Field School will also be featured in “Alien Sharks: Greatest Hits” Sunday July 22nd at 7:00 pm and “SharkCam Stakeout” Wednesday July 25th at 10:00 pm.

You can catch these shows on The Discovery Channel so tune in or set your DVR to record all of the fun and excitement.

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Releasing a nurse shark after a work up (Ginglymostoma cirratum)

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Measuring a Great hammerhead shark (Sphyrna mokarran)

Thank you to everyone in SRC and at the Field School for making this summer so absolutely amazing and one full of sharks!

I want to especially send a shout out to Dr. Hammerschlag, Steve, Abby, Shannon, and Trish from SRC for supporting, teaching and encouraging me. I might be the youngest person in our Lab but no one is more honored to work with you and everyone at SRC. Thank you SRC.

I’d also like to very much thank Julia, Catherine, Christian, Jake, and Nick from Field School for embracing and inspiring me. My experiences offshore and on-board with you and the others on each of our trips this summer was life changing (so much so that I am now studying for my Captain’s license). Thank you Field School.

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Releasing a nurse shark (Ginglymostoma cirratum) after a quick workup

If you love sharks, or are just curious to learn more about these wondrous creatures, I have GREAT news for you. You, too, can go shark tagging or attend other educational trips with us. To learn more about Shark Research and Conservation, please click here or to learn more about Field School, please click here. I hope you will consider joining us on what I promise will be a once in a lifetime experience that you will never forget.

Okay, enough about my summer “vacation,” my summer of sharks. I am off on another two trips with the SRC team this Saturday and Sunday and hope you will tune in and learn more about sharks on TV this week or join us out on the water soon. Fins up and enjoy the rest of your summer!

Dry Tortugas Shark Expedition

image003love sharks and am deeply proud to have just completed my first year as an intern in Dr. Hammerschlag’s Shark Research & Conservation (SRC) Lab here at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.

As summer begins and my Freshman year at RSMAS comes to an end, I am excited to share that I am about to cast off with some of my SRC lab partners and people from the Field School for a shark research expedition in the magnificent waters of the Dry Tortugas in the Gulf of Mexico. I’ll be traveling and living aboard the 55’ R/V Garvin’s research vessel with 13 other crew members and we will be performing all sorts of cool research on shark populations in the Gulf.

68 miles West of Key West, the Dry Tortugas are an untouched natural environment filled with incredible marine life and beauty. With the exception of Fort Jefferson, which maintains a small staff of National Park Service personnel, the islands are uninhabited and were named by Ponce de Leon in the early 1500’s after sailing by them and believing they were shaped like turtles (tortugas in his native Spanish language).

I visited the Dry Tortugas about three years ago on a family fishing and diving trip and fell in love with them. The waters are pristine, the beaches soft and bright white and the sea and marine bird life is abundant everywhere you look or swim. It’s simply an amazing place and I am very exited about conducting research there and enjoying another adventure in a place I love.

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While I am offshore on the expedition, please know that I will not have any cell, email or internet service but I hope to return will all sorts of stories and pictures to share with you. Enjoy the end of your school year and the start of summer and you can be sure I will be enjoying my time with the sharks and other awesome marine life in the Gulf of Mexico.

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Coral Bleaching of the Great Barrier Reef

The following article first appeared on the Research Blog for Dr. Neil Hammerschlag’s Shark Research and Conservation (SRC) Lab website at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science. To learn more about SRC, visit here: http://sharkresearch.rsmas.miami.edu/, or to learn more about the University’s marine science school, please click here: http://rsmas.miami.edu/.

By Delaney Reynolds, SRC intern

Coral reefs are some of planet earth’s most spectacular, diverse and important ecosystems. Our planet’s coral reefs provide important shelter, habitats, and a source of food for many different species of marine organisms. They also act as a critical food source to humans, as well a natural barrier to help protect our coastlines from hurricanes and associated storm surges. Sadly, coral reefs face growing risks including the possibility of extinction from a variety of stresses that leads to coral bleaching.

Coral Bleaching

Figure 1: Coral from which the zooxanthellae has been expelled, causing it to turn white (Image Source: http://en.wikipedia.org/wiki/File:Keppelbleaching.jpg)

Coral bleaching is the process in which zooxanthellae, algae living symbiotically within the coral, are expelled from coral colonies due to a number of factors including an increase in temperature, decrease in pH, exposure to UV radiation, reduced salinity, and bacterial infections. Zooxanthellae provide the coral 30% of its nitrogen and 91% of its carbon needs to the coral host in exchange for a shelter, as well as waste produced by the coral from nitrogen, phosphorus, and carbon dioxide that is required for the algae’s growth (Baird, 2002).

When corals bleach, it effects entire marine communities due to their immense diversity. Fish populations that reside around coral reefs “are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries” (Graham, 2008). Researchers have found that when an ecosystem endures physical coral loss, fish species richness is extremely likely to decline due to their heavy reliance on the coral colony itself (Graham, 2008).

Perhaps the most famous current example of coral bleaching is Australia’s Great Barrier Reef. Scientists have determined that the main cause of Great Barrier Reef coral bleaching is induced thermal stress and that about 90% of the reef has been bleached since 1998 (Baird, 2002). As the corals bleach and temperatures increase, researchers have determined that shark and ray species that live in the area may be vulnerable to these climactic changes.

Exposure of Ecological Groups of GBR Sharks and Rays to Climate Change Factors

Figure 2: Exposure of Ecological Groups of GBR Sharks and Rays to Climate Change Factors. This figure displays the vulnerability different elasmobranch species face due to climate change, as well as the specific effects of climate change that they are vulnerable to, in the specific zones of the Great Barrier Reef. (Image Source: Chin et al. 2010)

Most of the Great Barrier Reef is located on the mid-shelf of the ocean floor, the approximate mid-point between the shallower coast of Australia and the continental shelf where the ocean bottom significantly drops in depth. Researchers found that the mid-shelf is the area where most of the shark species studied reside, while most rays dwell in coastal waters or closer to the continental shelf. It was also found that both areas are the susceptible to rising temperature, increased storm frequency and intensity, increasing acidity, current alterations, and freshwater runoff, all being caused by climate change (Chin, 2010). Based on these findings, researchers have concluded that the areas these elasmobranchs live in should be protected and preserved. Species in these highly vulnerable areas should also be monitored and considered for future conservation actions, as many of the shark species are already experiencing the effects of climate change from some of the aforementioned factors.

Typically, sharks are considered some of the strongest animals on earth, and while they have lived on earth for at least 420 million years, they are slow to adapt. This slowness has impeded their ability to survive in our rapidly changing climate. In the near future it will be common to see some species of marine organisms demonstrate plasticity, the ability to adapt to their changing environment, but other species, such as elasmobranchs, are expected to simply distribute to other habitats in search of cooler waters. Even though sharks are a highly vulnerable species to climate change, they sit at the top of the trophic level in many different niches and, thus, wherever they migrate to, it will be easier for them to find food than it would be for other species such as fish or rays. However, this is most likely only the case for adult sharks as embryos and juvenile sharks may be more vulnerable to increased temperatures. For instance, researchers found that the survival of bamboo shark embryos decreased from 100% at current temperatures to 80% under future ocean temperature scenarios and that the embryonic period was also shortened, not allowing the embryo enough time to develop fully (Rosa, 2014).

To decrease the effects of climate change on coral bleaching, corrective and mitigation measures can be taken. By utilizing green energy sources such as implementing solar power or wind power, walking or biking, and driving electric cars, we can reduce our use of fossil fuels and carbon footprint, thus decreasing the amount of carbon dioxide polluting and warming our atmosphere and oceans. While underwater and not always visible, coral reefs are truly a vital part of our ecosystem and need to be cherished and protected for generations to come.

References

Baird, A. H., & Marshall, P. A. (2002, July 18). Mortality, growth and reproduction in scleractinian corals following bleaching on the Great Barrier Reef. Retrieved from https://researchonline.jcu.edu.au/1521/1/Baird_and_Marshall_2002.pdf

Chin, A., Kyne, P. M., Walker, T. I. and McAuley, R. B. (2010), An integrated risk assessment for climate change: analyzing the vulnerability of sharks and rays on Australia’s Great Barrier Reef. Global Change Biology, 16: 1936–1953. doi:10.1111/j.1365-2486.2009.02128.x

Graham, N. A., McClanahan, T. R., MacNeil, M. A., Wilson, S. K., Polunin, N. V., Jennings, S., . . . Sheppard, C. R. (2008, August 27). Climate Warming, Marine Protected Areas and the Ocean-Scale Integrity of Coral Reef Ecosystems. Retrieved from http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0003039

Rosa, R., Baptista, M., Lopes, V. M., Pegado, M. R., Paula, J. R., Trubenbach, K., . . . Repolho, T. (2014, August 13). Early-life exposure to climate change impairs tropical shark survival. Retrieved November 2, 2017, from http://rspb.royalsocietypublishing.org/content/royprsb/281/1793/20141738.full.pdf