you're reading...

Sharkbites Saturday

Sand Tiger Sharks: Tracking US east coast movement for better management



Kneebone J, Chisholm J, Skomal GB (2012) Seasonal residency, habitat use, and site fidelity of juvenile sand tigers Carcharias taurus in a Massachusetts estuary. Mar Ecol Prog Ser 471:165–185.

Kneebone J, Chisholm J, Skomal GB (2014) Movement patterns of juvenile sand tigers (Carcharias taurus) along the east coast of the USA. Mar Biol 161:1149-1163.

Dr. Jeff Kneebone with a juvenile sand tiger shark in PKD Bay, Ma.


Their fearsome appearance paired with a laid-back demeanor make sand tigers (Carcharias taurus) a species of contrasts; rows of teeth stick out of their mouth, but they are actually very docile. Not to be confused with the tiger shark (Galocerdo cuvier), the sand tiger shark is mainly a coastal species found in waters throughout the world. Although they go by many different names depending on the region (for example ragged-tooth shark, grey nurse shark), these are all the same species.

Sand tiger sharks, like other shark species, have what’s termed a “k-selected” life history. Think of this as having reproductive and growth rates similar to humans, where sharks mature at late ages, reproduce in small numbers, and live relatively long lives. Sand tigers have been observed to reach ages upwards of 12 years, reaching a maximum length at around 10 feet. Sand tiger sharks have a unique form of reproduction in comparison to other sharks. It’s called inter-uterine cannibalism, where the largest pup in the womb at a length of around 4 inches eats the other developing embryos, in true survival of the fittest fashion. Because one pup consumes the rest, sand tigers have a very low reproductive output, meaning they only produce one to two offspring every two or three years. This makes the population extremely susceptible to over fishing, given they can’t replace sharks taken out of the population very quickly. Evidence of this exact problem was seen in the 1970’s with estimates of population decline as high as 80-90%, prompting the National Marine Fisheries Service to prohibit possession of sand tiger sharks throughout their range (NMFS, 1999).

Figure 1. Map of the acoustic receiver arrays where juvenile sand tiger sharks were detected in Kneebone et al. 2014 .

The Study:

In the US, sand tiger sharks are found throughout the east coast, however little was known about their use of this wide range until the last decade. Perhaps if we knew more about their movement patterns and what areas are important for their survival, we could help assist  population recovery. To do just that, a study began in New England after many fishing reports of juvenile sand tiger sharks being caught in commonly fished local bays. As seen in Figure 1, the Plymouth, Kingston, Duxbury (PKD) Bay in Massachusetts and Point Judith in Rhode Island were sampled from 2006 to 2011 for these juveniles using conventional rod and reel fishing practices. After capture, sharks were surgically implanted with an acoustic tag (Fig. 2) that works similar to an EZ pass, where date and time is recorded when a tagged shark swims by a listening station or receiver. This type of tagging technology is extremely common among various researchers, creating a network along the US east coast of these receiver stations that can pick up any animal with an acoustic tag from any study (Fig 1.). Additionally some sharks were also tagged with a PSAT tag, a type of archival satellite tag that is attached near the dorsal fin. These were set to pop off the shark and relay location and depth data to a satellite after a specific period of time. Unfortunately there was a large amount of technological error with these tags with only three reporting data; nonetheless the information obtained is still very interesting.

Figure 2. An acoustic tag (bottom) and receiver (top) that can be used to track shark movement.


            Acoustic tracking data from the array of receivers throughout the US East coast has shown that these juveniles have a very unique and arduous migration path. Sharks were detected in New England waters in the summer and fall, spending their time in bays and estuaries foraging for prey like fish and crustaceans. However in the winter and into the spring the little sharks migrated down to the south to the coasts of Florida, Georgia, and the Carolinas (Kneebone et al. 2014). Data from one satellite tag that was attached to a particular shark for 275 days showed the same pattern (Fig. 3). That particular tagged shark measured in at a little over three feet and somehow traveled approximately 3680 miles! Not only does this show the interesting movement patterns of juvenile sand tiger sharks, but is also a testament to the tenacity of sharks. Additionally, the tagging research shows that some bays like PKD Bay in New England are extremely important seasonal nursery grounds for these species, with juveniles spending the majority of their time within these areas during the balmier months of the year (Kneebone et al. 2012).

Figure 3. A satellite tag track from a juvenile sand tiger shark tagged in PKD Bay.


It is important to note that these interesting migration patterns are specific to juvenile sharks, where adults are known to have different movement patterns. The adults are more closely concentrated in the mid-Atlantic region, with a large concentration around Virginia and Delaware. It is possible juveniles don’t spent time in the same areas as adults to avoid competition for food, or even predation of small juveniles by larger adults!

Overall this type of shark movement research can help scientists predict what areas are important for a shark population, increasing the effectiveness of management decisions toward the species; protecting areas where sharks grow or hunt as juveniles helps the overall health and stability of the population. Although we are still waiting to hear if PKD Bay will be listed as a NOAA Habitat of Particular Concern, the state and federal regulations that currently protect this species throughout its range are a great start.


2 Responses to “Sand Tiger Sharks: Tracking US east coast movement for better management”

  1. Can I send you a picture

    Posted by Darren Finch | September 16, 2018, 12:15 pm
  2. I caught this Shark this weekend at Cape Cod in Nantucket sound
    What kind of Shark is this

    Posted by Darren Finch | September 16, 2018, 12:14 pm

Post a Comment


  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 4 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 9 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com