The first newsletter of 2018 features Science Team member Grace Casselberry!
By, Michelle Jewell
The fields of Taxonomy (classification of species) and Nomenclature (naming of species) are complex but critical aspects to any biology scheme-of-work. The scientists at the Gills Club have developed a fun activity-based resource that uses sharks and rays to make understanding these concepts a breeze. The activities are intended for grades 5-8, however, classes of all ages have enjoyed this project.
The course materials explain the basics and origins of nomenclature. Then, we task students to individually build brand new species of shark and ray by combining Latin and Greek nomenclature cards. Once you have a group of new shark and ray species, your class will have to agree on how to classify them into particular groups. Finally, we use the brilliant resource of the Chondrichthyan Tree of Life to discuss real-life examples of shark and ray classification and nomenclature.
You can download all of the free resources below.
We talked a bit about the science I do back in September, but I’m also the Intern Coordinator for the Shark Research and Conservation Program at the University of Miami. This means that I’m responsible for training interns to safely work with and handle sharks, as well as teaching them to give talks on shark ecology and biology. A lot of the amazing Gills scientists you’ve heard from so far have talked about the work that they do in the field or the lab, and while I love both of those things, the most important thing I do every day is help to teach and train the next generation of shark scientists—including (someday) some of you! So after a few parents contacted me with questions, I thought it might be helpful to have a talk about what you can do to help prepare for a successful career in marine science (other than studying hard).
1. Get comfortable on and in the water. If you want to do field work with marine life, you’ll need to go where they are, and that’s going to include being on boats and probably (at least sometimes) swimming and diving. I can’t tell you how many times I’ve had to jump in to unwrap a rope stuck around a boat propeller; being comfortable in the water makes everything else easier. You don’t have to live near the ocean—practicing swimming in a pool or lake will help too!
2. Get some experience! Lots of aquariums or scientific programs need volunteers to help with tasks (our program wouldn’t run without our 25+ amazing UM intern volunteers). Be willing to do anything when you’re starting out. A lot of the work we do involves chopping bait into pieces, cleaning or preparing gear, and other stuff that might seem gross or boring. Doing whatever needs to be done without complaint will set you apart and really show your work ethic—which usually leads to more opportunities.
3. Be detail oriented and good at listening to instructions. You can get better at this if you aren’t naturally great at it by practicing the skills you’ll need (like tying knots) and by making lists. When I select interns, I look for students who I think I can trust to listen to me and do what I tell them even in confusing or intense situations. There really is a big difference in field work between doing something kind of right and doing it exactly right. And if you aren’t sure what to do, ask! It’s much better to check in and get it right than do it wrong.
4. Be polite, but persistent. I used to be really shy, and it wasn’t until I started getting hundreds of emails from prospective interns that I realized that if someone doesn’t respond to you, they may not be ignoring you…it may just be that your email or phone call was accidentally forgotten. Sometimes I get really behind on responding to people, especially if I’ve been in the field a lot. It’s not because I don’t care! Always, always communicate in a way that is polite and professional, but if you don’t hear back, send a follow-up email.
5. Learn how to be part of a team. Even if you don’t like sports, join the science or debate team, or a marine science club. Practice working and cooperating with other students, even those who aren’t your favorite people. When choosing new interns, I don’t only think about their qualifications, but about how they will fit into and get along with our existing team. I try to avoid hiring interns who don’t work well with others. These are skills you can start building at any age that will help you throughout your career—even if it isn’t in marine science. If you have questions for me or you’re interested in having one of our outreach interns Skype with your class, you can also ask your teacher to contact me via Facebook or at cmacdonald (at) inbox.com to set that up.
When I was 14 I decided that I would be a marine biologist, not just any marine biologist, a shark biologist. This was before I saw the ocean for the first time. A whole bunch of people just said “what?” No, I’m not confused, this is how it happened. And yes, almost everyone said I was crazy.
My point in this blog is to say that it doesn’t matter where you come from, you can be who or what you want no matter what your starting point. All you have to do is apply yourself and go for it. So where do I come from – where did I start? I grew up in South Dakota until I was 14 when my family moved to Colorado. Very solidly in “the middle” of the US – no growing up on beaches for me. I don’t know where the decision came from to go study sharks, it was just there.
So how did I manage getting from the middle of the US to becoming a shark researcher? Two main ingredients: support from my family and hard work. My parents are amazing. While everyone else was telling me I was crazy they consistently said – don’t listen to anyone else, if this is what you want to do then put your head down and go do it. One of the most vivid memories I have from high school has to do with this support. I went to the guidance counsellor to ask for some material about colleges and told him I wanted to study marine biology. He told me I would never make it, would never get a job and that I should change my senior year classes so I could become a bookkeeper or accountant. I went home in tears. My Mom happened to be home when I walked in that day (she was usually at work) and she asked me what happened. I told her the story and she asked who had told me this. She then phoned the school, asked for the counsellor and proceeded to tell him off. I clearly remember her saying “Don’t you dare tell my kid she can’t do something she wants to do!” She then hung up the phone and said to me, “don’t ever listen to people like that, if you want to do it, go do it”. Several times this journey has gotten difficult and I have considered quitting. Each of these times my family has been there to support me and encourage me to keep chasing my dream. To say my family have been crucial to my success would be a huge understatement.
A photo of me from South Dakota holding a sunfish I caught in one of the local lakes.
So, if you don’t have someone in your life who will tell you the things my family has, find someone who will, or let me be that person. Do not give up on yourself, do not give up on your dreams and goals. Work hard and give it your best. If it doesn’t work out at least you know that you gave it every chance.
So here I am, a shark biologist with almost 20 years of experience in the field and sometimes I wonder – who was the crazy person all those years ago? I don’t think it was me.
I’ve moved on to fishing for bigger things – fishing for blacktip sharks in the Florida Keys
Follow her on twitter: @ExpatScientist
If you have ever avoided parking on a risky-looking street or taken a different route between classes to avoid a bully, your behaviour has been altered due to the perceived presence of ‘predators’. In the wild, prey animals also change their behaviour when they think predators are around, and these altered anti-predator behaviours can often influence other species, and then influence more species, and eventually change the entire ecosystem. This is an example of indirect effects predators have on ecosystems.
My research has focused on these principles of predator/prey interaction in the ocean, and a great place to study oceanic predators and their prey are Cape fur seal colonies in South Africa. Every summer in the southern hemisphere (November), Cape fur seals give birth to thousands of pups. For example, the seal colony Geyser Rock has a population of about 60,000 Cape fur seals and every year they give birth to 10,000 seal pups! By winter (April – September) these 6 month old ‘young-of-the-year’ seals begin to venture off the colonies and swim offshore with the adults to the fishing grounds. These young-of-the-years are typically slow, plump from months of a mostly fat milk diet, and – most importantly – naïve. White sharks take advantage of this naivety and aggregate closely around seal colonies every winter to catch leaving/returning seals. Young-of-the-year pups are forced to learn how to avoid sharks quickly or suffer some rather permanent consequences! This means that during a full year, every seal colony goes through a period of high white shark presence (winter) and very low to no white shark presence (summer). Therefore, we can see how seals act ‘normally’ during the summer when there are no/very few sharks and how they change their behaviour in the winter to avoid white sharks.
A) The Western Cape of South Africa with B) Seal Island, False Bay and C) Dyer Island & Geyser Rock.
Also, there are many different kinds of seal colony islands along the coast, which lets us ask more questions about how seals use their environment to avoid sharks. I conducted my study at the Dyer Island/Geyser Rock system, which is home to ‘Shark Alley’ as well as many shallow reefs, kelp forests, and shipwrecks. About 100km to the east is another seal colony called Seal Island, which is a world-famous spot to see white sharks predate on seals, but this island system lacks the abundant nearby structures/reefs/kelp forests that are present at Geyser Rock. By looking at these two different kinds of islands, we can also examine how structures – or ‘refugia’ – may alter how seals avoid white sharks at Geyser Rock from how seals avoid white sharks at Seal Island.
And here’s what we found…
Do all of these structures and anti-predatory tactics of Cape fur seals change white shark movements around Geyser Rock? Most definitely! Check out that study (and infographic!) here.
This project was funded by the Dyer Island Conservation Trust and supported by Marine Dynamics shark tours, Volkswagen South Africa, and OCEARCH. The infographic was designed by EDNA Science. You can read the detailed scientific publication on Behavioral Ecology & Sociobiology by clicking here.
*Helena tags and collects biological samples from juvenile and adult blue sharks on federal research cruises
5:30 a.m. (~sunrise)-6:30 a.m. Set the longline gear (Set 1)
Setting gear requires baiting the hooks (~200 per set), putting lightsticks above each hook (these attract fish to the bait in the deep dark waters), throwing the line out into the water, and attaching and releasing buoys to separate baskets of hooks. This process usually takes around an hour to an hour and a half. This will be set #1 and will soak (soak = stay in the water) for 10 hours before we haul it back on deck. Immediately after set #1, we will motor to another area to do 1-2 shorter sets that will only soak for ~2 hours each before we haul the gear back.
8:30 a.m.-9:30 a.m. Set the longline gear (Set 2)
9:30 a.m.-10:30 a.m Prepare tagging and sampling gear for haulback; deploy CTD (Conductivity, Temperature, and Depth device)–CTD provides us with information about the habitat in which we are fishing
10:30 a.m.-12:00 p.m Haulback of Set 2
When we are ready to haul the gear back on deck, the main line will be pulled back onto the spool and each hook is removed and put back into a large bin to be used for setting the gear next time. As the animals come up, we assess the condition of the fish, pull them onto a cradle that gets hoisted onto the deck with a hydraulic winch, and begin working up the animal. Sharks will immediately get a ventilator (hose with specially fitted mouth piece) to run water over their gills, a wet chamois or towel is used to cover their eyes (which keeps them calm), and the hook is removed. We take length measurements and determine sex of the animal (claspers vs. no claspers). A small corner of the dorsal fin is clipped and saved in alcohol as a DNA sample, and depending on the size of the shark and which project we want to use that sample for, either a conventional tag (a thin piece of plastic that contains a unique ID number and contact information for fishermen to use in the event of recapture of the animal) or an electronic tag (that provides data on location and movement patterns) is inserted near the dorsal fin. We will also be taking blood samples to measure lactate levels, which can give us information on the stress level (condition) of the fish. Some of the sharks will also receive a secondary tag (with reward information for recapture) and antibiotics that function as a marker of when they were captured and can be used to determine age and associated growth of the shark if it is recaptured in the future and the vertebrae are returned to our lab. Once the sharks have been tagged and/or sampled, we return them to the water and assess condition once again. Sharks that are not alive upon haulback of the longline will be processed for biological samples that include: stomach (can be used to determine what the shark has been eating and which habitats it exploits), liver/muscle/heart tissues (used for stable isotope analysis which can tell us about its movements and where it spends a lot of its time), and gonads (used to determine maturity and provide information on reproduction).
1:00 p.m.- 2:00 p.m. Set the longline gear (Set 3)
3:00 p.m.- 4:30 p.m. Haulback of Set 3
5:30 p.m.-7:00 p.m. Haulback of Set 1
Repeat for 10 days and pepper in some tagging of opah and swordfish. Rough seas, long days, hard work, and lots of fun!
There are a lot of people studying shark movements these days. It seems like most conferences I go to or web sites I visit have a heavy tracking focus. This is interesting to the handful of us who have been doing this for a while – suddenly what we do is really popular! So why do people track sharks? Some of them do it because it’s cool and interesting, but ultimately it is hopefully useful for more than scientific curiosity.
I have spent the last 15 or so years tracking sharks – why do I do it? Although I also think tracking is cool, fun and interesting my tracking research started out trying to answer a specific management based question: how long do juvenile sharks stay in a nursery area? That research told us how dependent they were on that area and how important it was for their survival. Since then I have done a number of projects that looked at how sharks use space relative to marine protected areas. The driving question: how much is an area that is closed to fishing protecting sharks? To answer that we have to think about how long sharks stay inside the protected area and how often they move in and out.
One of my students, Danielle Knip did a really nice analysis of closed area benefits for pigeye and spottail sharks in a north Queensland bay. What she found was that over the course of 2 years these sharks only spent 22-32% of their time inside the protected area. That means they weren’t getting much protection from fishing. It was an interesting finding but the closed area wasn’t actually designed to protect coastal sharks so we weren’t totally surprised to see such low levels or protection.
A pigeye shark (top) – a close relative to the bull shark, and a spottail shark (bottom). The two species were tracked to see how long they stayed inside a marine protected area.
More recently I’ve been tracking reef sharks to see if protecting a reef protects the sharks that use it. The answer: it depends. That’s a scientist answer for you. We never want to say yes or no until we tell you the whole back story. In this case though, the “depends” actually relates to the species of shark. For species that spend a long time on the same reef they can get a lot of protection from closing their reef to fishing. For example, Mario Espinoza and I recently showed grey reef sharks can spend years on a single reef based on data from two separate sections of the Great Barrier Reef. However, if they spend a lot of time on a reef that isn’t closed to fishing they may be more exposed than average because fishing pressure might be directed to that reef due to closed areas. Things that move more widely though, like tiger sharks, silvertip sharks and bull sharks get much less value from closed areas because they move so much.
Map showing the movements of a female 188 cm tiger shark moving between coral reefs. Reefs in blue and yellow are open to line fishing, green and pink are closed to fishing. Blue triangle and red square indicate the beginning and end of the track.
So what does all this mean? It means we can’t just use closed areas to protect sharks – a lot of them just swim right out. We have to use other management measures like catch limits to help protect them. The other thing this means is that we really do need to understand how much the animals we are trying to protect move. How long they stay and where they actually go are critical to our ability to get management right.
Papers related to this story:
Heupel MR and Simpfendorfer CA (2015) Long-term movement patterns of aoral reef predator. Coral Reefs 34: 679-691
Heupel MR, Simpfendorfer CA, Espinoza M, Smoothey A, Tobin AJ and Peddemors V (2015) Conservation challenges of sharks with continental scale migrations. Frontiers in Marine Science doi: 10.3389/fmars.2015.00012
Espinoza M, Heupel MR, Tobin AJ and Simpfendorfer CA (2015) Residency patterns and movements of grey reef sharks in a semi-continuous reef environment: evidence of reproductive behaviour. Marine Biology 162: 343-358
Knip DM, Heupel MR and Simpfendorfer CA (2012) Evaluating marine protected areas for the conservation of tropical coastal sharks. Biological Conservation 148: 200-209.
Today I joined Gills Club Scientist Rachel Scharer and Florida Fish and Wildlife to help tag and sample sawtooth sawfish! Florida storms chased us off the water, but not before we found a beautiful female sawfish. The smalltooth sawfish is an endangered species and the work Rachel and her team are doing will help fill in important missing data gaps for this species. Once we captured the sawfish, we measured her length and her disc width, counted her rostral teeth, took a DNA sample and fitted her with an ID tag, PIT tag and an acoustic tag. All tags will help ID her in the future, and monitor her movements! It was awesome to see this beautiful and rare species!
Hi Gills! It's been a while but I've been working hard since my last post. One of my research projects involves looking at relationships between anatomy and the environment of swordfish and bigeye thresher sharks. While these fishes are unrelated, they are both highly active, predatory species inhabiting the open ocean or pelagic environment. Unlike other active, pelagic fishes, swordfish and bigeye thresher sharks routinely make long dives (10+) hours from warm surface waters (>60F) to cold depths (~40F). Despite
their similar ecologies, swordfish and bigeye thresher sharks exhibit different anatomies. Swordfish appear endothermic, while bigeye thresher sharks appear ectothermic. This week I had the privilege to examine the anatomy of a freshly landed swordfish. Endothermy (sometimes called warm-blooded) refers to elevation of body temperature above the environment. Humans are endothermic. We typically maintain a body temperature of 98.6F regardless of environmental temperatures. Some fishes are regionally endothermic. Tunas and lamnid sharks (e.g. great white, mako, porbeagle) elevate red muscle tissue, or that muscle used for sustained/marathon swimming, but not the temperature of the entire body, above water temperature. Swordfish are thought to be regionally endothermic because the red "marathon swimming" muscle is located close to the spine and the associated arteries and veins form a complex arrangement, called a counter-current heat exchanger, which keeps muscular produced heat at the muscle. The arrangement of the white muscle and the presence of the counter-current heat exchanger creates a "heated blanket" that warms the red muscle and travels with the fish. Most fishes are ectothermic ( sometimes called cold-blooded) and red muscle temperature is similar to water temperature. Bigeye thresher sharks are ectothermic because the red muscle is located directly beneath the skin and they do not possess the arteries and veins to form an exchanger. This means that while both species are active in cold waters, swordfish red muscle may not fully experience low temperatures because of the regional endothermy, while bigeye thresher shark red muscle must experience temperature changes during dives from the surface to cold depths.
Last week I went out on a 2-day research cruise in the northern Gulf of Mexico to tag and release sharks! We catch our sharks by using a fishing technique called bottom longline. The longline is 1 mile long (1000 lb test monofilament) and we have 100 gangions (clip, line, and hook) that are attached to the main-line that sits on the bottom. Every time that we set a bottom longline we take abiotic parameters including temperature, salinity, and dissolved oxygen. To do this, we use a piece of equipment called a CTD (conductivity, temperature, and depth recorder). We drop the CTD to the bottom of where we are fishing and the CTD takes a full water column profile. The CTD can take thousands of readings in the course of a minute!
Every shark that we bring on board (which can be up to 22 different species!!) we measure, weigh, sex, tag and release. We use three different types of tags: 1) roto tag, which is a plastic tag that is placed in the dorsal fin of smaller sharks, 2) M-tag, which is a metal dart tag that is placed into the musculature of larger sharks, and 3) pop-off archival tag (PAT), which is a satellite tag that we use to track movements of certain species of sharks. The roto and M-tags have unique fish identification numbers on them as well as a telephone number that an angler can call if one of our tagged sharks is recaptured (this happens multiple times a year). On this research cruise, we put out around 100 roto and M-tags on 7 different species of sharks!
I thought I would post this picture so you can see a little bit of what goes on in the lab. When we're collecting DNA data from our shark and ray species, the first step is to shear the DNA into small pieces so its easier for us to sequence. That machine in the top left does that job for us, it's called an ultrasonicator and uses sound energy to chop up the DNA. You can see an image of how the DNA looks once its been fragmented in the bottom right. It's basically a smear which tells me there are lots of pieces all around the same size, which is a good thing! I worked on some interesting species this day, including a new species of whaler shark, Carcharhinus humani, which was just described a few weeks ago.
Hello Gills! Today I am on the water with Cynthia Wigren and the Atlantic White Shark Conservancy looking for white sharks! We are aided by a spotter plane which is flying up and down the coast looking for the sharks. If the spotter pilot sees one, he will direct us to it! Right now he is reporting good visibility for shark spotting. while we look around, we are also listening for acoustically tagged sharks with a VR100 hydrophone; any shark that has an acoustic tag on it will be detected and report back a characteristic ping sequence and ID number which tells us which shark it is! Conditions are good and we're seeing lots of seals. Fingers crossed! Hope all you Gills are having a nice Sunday!
We've arrived at Seal Island, stunning flat and calm conditions. Let's hope we see some sharks!
Here's Seal Island, in the breeding season there are 70 000 cape fur seals present. The sharks arrive at the island when the young of the year are starting to venture away from the island. Today we saw 3 white shark-seal predations. Lots of sharks around, but not so many seals leaving today.