Sharkpedia
Meghan Holst and Amani Webber-Schultz
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Top 10 Sharkpedia Episodes
Goodpods has curated a list of the 10 best Sharkpedia episodes, ranked by the number of listens and likes each episode have garnered from our listeners. If you are listening to Sharkpedia for the first time, there's no better place to start than with one of these standout episodes. If you are a fan of the show, vote for your favorite Sharkpedia episode by adding your comments to the episode page.
Tiger Shark Teeth with Julia Türtscher
Sharkpedia
05/11/22 • 56 min
Everything you need to know about Tiger Shark teeth! This week PhD student Julia Türtscher joins ut to tell us amazing things about shark teeth, like, did you know males and females can have differently shaped teeth? Or that teeth can change SEASONALLY?! Learn everything you need to know about shark teeth and what Julia and her team learned about tiger sharks from preserved jaws!
This week we dive into Julia's article, "Heterodonty and ontogenetic shift dynamics in the dentition of the tiger shark Galeocerdo cuvier (Chondrichthyes, Galeocerdidae)" Türtscher et al. (2022)
Article Summary:
The lifelong tooth replacement in elasmobranch fishes (sharks, rays, and skates) has led to the assemblage of a great number of teeth from fossil and extant species. Evaluating tooth morphology is important for taxonomic descriptions, and understanding how elasmobranchs have evolved when comparing extant teeth to fossil teeth. Heterodonty (various tooth morphologies) occurs in most elasmobranch species and has proven to be one of the main challenges for comparing extant and fossil teeth. Although numerous shark species are discovered and described every year, detailed descriptions of tooth morphologies and heterodonty patterns are lacking or are only insufficiently known for most species. In this study, Türtscher and colleagues generate 2D models of tiger shark teeth Galeocerdo cuvier to describe how teeth develop and change from embryo to adult. Türtscher and colleagues' results reveal rather gradual and subtle shape changes from embryos to adults, mostly characterized by the increasing size and complexity of the teeth. They furthermore provide the first comprehensive description of embryonic dental morphologies in tiger sharks. Finally, multiple cases of tooth file reversal are described. This study contributes to our knowledge of dental traits across age stages in the extant tiger shark G. cuvier and provides a baseline for further studies on the dental variation in sharks. Therefore, it has the potential to assist in elucidating the underlying developmental and evolutionary processes behind the vast dental diversity observed in elasmobranch fishes today and in deep time.
Follow Julia Türtscher on Twitter @JuTuertscher and Instagram @julia_tuertscher
Learn about shark sightings in the Mediterranean @haisichtungen_mittelmeer
Follow Sharkpedia on Instagram and Twitter @SharkpediaPod
Connect with Sharkpedia:
Email: [email protected]
05/24/21 • 56 min
On this episode, Meghan and Amani interview Dr. Catherine Macdonald, Co-Founder and Director of Field School in Miami, about her publication "Conservation potential of apex predator tourism" (Macdonald et al., 2017). We discuss some of the threats that shark populations face, when tourism can play a potentially positive role in shark conservation, and the complexity of working with diverse groups of people towards the same conservation goal. Get ready to jump into the world of shark conservation!
02/19/24 • 52 min
This week we had a very fun time talking with Dr. Taylor Chapple about maximizing datasets with video biologgers that are attached to sharks! Are you listening to the podcast and wondering who Dr. Alex McInturf is? Listen to our very first interview episode in Season 1!
We chat with Dr. Chapple about his article, Ancillary data from animal-borne cameras as an ecological survey tool for marine communities
Article Summary: Underwater visual surveys, such as diver-based video surveys, are a common and essential technique in measuring and managing marine ecosystems. However, there are several limitations to doing such surveys, such as recreational diving depth limitations, or animal interactions that preclude safe diving (such as White shark - sea lion interactions). Biologging camera tag devices are commonly used to study a single, focal species' behavior. However, ecosystem-wide data is collected and could be used to monitor and assess habitats that may not be accessible to humans. In this study, Chapple et al. use a video camera logger on a White shark off Gansbaai, South Africa, and a Grey Reef shark within the Chagos Archipelago, to determine if video logging could be used to measure the habitat structure of their respective environments. They used established methods to analyze video data and found that the biologging from the sharks was relatively comparable. Using biologgers such as the ones used in this study could maximize the overall cost and effort of tagging deployments by gathering more ecosystem-wide data, than just the focal species data.
07/26/22 • 53 min
Just in time for Shark Week, we're going down under to investigate what warming waters will do to the distribution of tiger sharks on the east coast of Australia with tiger shark expert, Dr. Yuri Niella!
This week we break down Dr. Yuri Niella et al. (2021) article, "Forecasting intraspecific changes in distribution of a wide-ranging marine predator under climate change."
Article Summary: (modified abstract)
Climate change is causing animal distributions to shift in response to changing temperatures. Typically shifts in these behaviors are evaluated at the species level, but in this study, Nuriella et al. studied behavioral shifts at the individual level. They investigated 115 tiger sharks, Galeocerdo cuvier, from 2002 to 2020, and evaluated how behavior and distribution differed between sex and maturation class (meaning, juveniles or adults). With this long-term data set, Nuriella et al. modeled how behavior and distribution may continue to change in tiger sharks to 2030, and included environmental factoers and predicted occurence of potential prey. Generalised Linear and Additive Models revealed that water temperature change, particularly at higher latitudes, was the factor most associated with shark movements. Females dispersed southwards during periods of warming temperatures, and while juvenile females preferred a narrow thermal range between 22 and 23 °C, adult female and juvenile male presence was correlated with either lower (<22 °C) or higher (>23 °C) temperatures. During La Niña, sharks moved towards higher latitudes and used shallower isobaths. Inclusion of predicted distribution of their putative prey signifcantly improved projections of suitable habitats for all shark classes, compared to simpler models using temperature alone. Tiger shark range of the east coast of Australia is predicted to extend~3.5° south towards the east coast of Tasmania, particularly for juvenile males. This study will assist in evaluating the consequences of climate change to species distribution.
Follow Dr. Niella on Twitter @Yuri_Niella
Follow Sharkpedia on Instagram and Twitter @SharkpediaPod
Connect with Sharkpedia:
Email: [email protected]
06/06/22 • 64 min
Have you ever wondered how sharks perpetually regenerate their teeth? Why can't humans do the same thing, or can they?! This week expert Dr. Gareth Fraser joins us to tell us all about this special shark superpower.
We jump into Dr. Fraser's article, "The Dental Lamina: An Essential Structure for Perpetual Tooth Regeneration in Sharks" (Fraser et al. 2020)
Article Summary:
Methods of studying evolutionary, development, and regenerative biology have been improving over the past few years. This paper utilizes the embryonic small-spotted catshark (Scyliorhinus canicula) using new techniques that allow them to research key developmental and regenerative processes that classical models can not. The development of shark teeth and their subsequent regeneration is a lesser studied area of research. Fraser et al. explore the role of the dental lamina, the tissue that is the first evidence of teeth in an embryo, in the development of highly regenerative dentition in sharks. Sharks regenerate whole teeth at a time as opposed to other systems such as the murine model where incisors exhibit continuous renewal and growth of the same tooth. Studying shark teeth on a genetic level can provide important context into the evolution of vertebrate tooth regeneration.
Learn more about Dr. Fraser's work at: www.fraser-lab.net
Follow Dr. Fraser on Twitter @garethjfraser
Follow Sharkpedia on Instagram and Twitter @SharkpediaPod
Connect with Sharkpedia:
Email: [email protected]
05/23/22 • 47 min
Manta ray research using drones?! This week guest expert Vicky Fong joins us to tell us all about the swimming behavior of manta rays, and why understanding these behaviors can be important for their conservation!
We jump into Vicky's article, "Using Drones to Assess Volitional Swimming Kinematics of Manta Ray Behaviors in the Wild" (Fong, Hoffmann, and Pate; 2022)
Article Summary: (abstract)
Drones have become increasingly popular tools to study marine megafauna but are underutilized in batoid research. They used drones to collect video data of manta ray (Mobula cf. birostris) swimming and assessed behavior-specific kinematics in Kinovea, a semi-automated point-tracking software. They describe a ‘resting’ behavior of mantas making use of strong currents in man-made inlets in addition to known ‘traveling’ and ‘feeding’ behaviors. No significant differences were found between the swimming speed of traveling and feeding behaviors, although feeding mantas had a significantly higher wingbeat frequency than traveling mantas. Resting mantas swam at a significantly slower speed and wingbeat frequency, suggesting that they were continuously swimming with the minimum effort required to maintain position and buoyancy. Swimming speed and wingbeat frequency of traveling and feeding behaviors overlapped, which could point to other factors such as prey availability and a transitional behavior, influencing how manta rays swim. These baseline swimming kinematic data have valuable applications to other emerging technologies in manta ray research.
Follow Vicky on Instagram @vicky.fong
Follow the Florida Manta Project on Instagram @MarineMegaFauna and Jessica Pate @FloridaMantaGirl
Follow Sharkpedia on Instagram and Twitter @SharkpediaPod
Connect with Sharkpedia:
Email: [email protected]
04/25/22 • 57 min
Basking sharks on the West Coast USA?!?! Dr. Alex McInturf returns from season 1 and gives us a MASSIVE update about her career, basking shark populations, and the tea on basking shark conservation. Did you know basking sharks were along the West Coast USA?! Most don't, because these sightings are now extremely rare.
This week we breakdown Dr. McInturf's article, "“Spatial Distribution, Temporal Changes, and Knowledge Gaps in Basking Shark (Cetorhinus maximus) Sightings in the California Current Ecosystem” McInturf et al. 2022
Article Summary:
Basking sharks are the world’s second largest fish, and one of the three filter-feeding shark species. Basking sharks are very slow growing, long-lived animals that have a 20-30 year generation time (meaning, there is 20-30 years between two consecutive generations). This species is found around the world and is capable of large-scale migrations. Basking sharks will aggregate during certain months, known as basking shark “hot spots”. Hotspots were observed Eastern North Pacific coastline and California Current Ecosystem, but are now rarely observed. McInturf et al. (2022) compiled recent and historical datasets to examine temporal patterns of basking shark sightings in the California Current Ecosystem, and determine the spatial, temporal, and environmental drivers that have affected basking shark presence and distribution for the last 50 years. Their research showed that there were nearly 4,000 sharks sighted per year until the 1990s, after which sightings are extremely rare. There was also a 50% decline in basking shark school size. McInturf et al. provide insight to why the basking shark population declined, and offer suggestions for future research and conservation efforts.
Learn more about Dr. McInturf at https://alexandramcinturf.squarespace.com/
Contact the Irish Basking Shark Group: at https://www.baskingshark.ie/
Follow Dr. McInturf on Instagram and Twitter @DrSurfNTurf
Contact Dr. McInturf at [email protected]
Follow Sharkpedia on Instagram and Twitter @SharkpediaPod
Connect with Sharkpedia:
Email: [email protected]
01/08/24 • 57 min
This week we are joined by Dr. Julia Mason to talk about fishers ecological knowledge of Smooth Hammerhead sharks in Peru! Why is it important to incorporate fishers into management decisions? Why aren't they always included in the management discussion of species they target? Find out this and more!
We read Dr. Julia Mason's article, Fishers' solutions for hammerhead shark conservation in Peru
Article Summary: Shark populations have been declining worldwide, with heavy implications for the health of our oceans. The increase in regulations put forth by both national and international entities to protect declining shark populations has had limited effectiveness with a major challenge in policymaking coming from a lack of data for small-scale fisheries. In Peru, sharks are mostly caught through small-scale fisheries and are targeted for human consumption rather than strictly for fins. In 2016, Peru implemented a seasonal ban on hammerhead fishing from January to March of each year in an attempt to restrain fishing pressure. However, this seasonal ban does not protect breeding females, which are present in September-December. Smooth hammerheads were the 3rd most caught shark in Peru before this ban, behind the blue shark and shortfin mako. This article aims to better understand fisher perspectives on this ban as well as record their solutions. Mason et al. interviewed boat owners and captains in 3 major Peruvian ports, San Jose, Mancora, and Salaverry. They found that the majority of fishers welcome conservation measures with a smaller percentage objecting, largely due to a lack of transparency and fisher participation in the ban development and implementation process. Additionally, fishers reveal gaps in the ban's effectiveness based on the movement behavior of hammerhead sharks.
You can follow Dr. Julia Mason @JuliaGMason
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FAQ
How many episodes does Sharkpedia have?
Sharkpedia currently has 33 episodes available.
What topics does Sharkpedia cover?
The podcast is about Nature, Podcasts and Science.
What is the most popular episode on Sharkpedia?
The episode title 'Let's Jump In' is the most popular.
What is the average episode length on Sharkpedia?
The average episode length on Sharkpedia is 54 minutes.
How often are episodes of Sharkpedia released?
Episodes of Sharkpedia are typically released every 14 days.
When was the first episode of Sharkpedia?
The first episode of Sharkpedia was released on May 4, 2021.
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