Sharkpedia (Meghan Holst and Amani Webber-Schultz)

This week we talk about Manta ray nursery habitat off the coast of Florida with expert Jessica Pate! We break down her article, "Urban Manta rays: potential manta ray nursery habitat along a highly developed Florida coastline" (Pate & Marshall 2020). We discuss what defines an area as nursery habitat, how habitat off the Florida coast fits these criteria for Manta rays, and why this is so important for Manta ray conservation. Get ready to jump into the world of Manta rays!

Satellite track a Manta ray: https://www.trackturtles.com/leo/

You can follow Jessica on Instagram @floridamantagirl, and learn more about the conservation work let by the Marine Megafauna Foundation at https://marinemegafauna.org/

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This week we are jumping into a problem for sharks: entangling in marine debris with expert Kristian Parton! With Kristian's help we will review his article, Parton et al 2019 “Global review of sharks and ray entanglement in anthropogenic marine debris”. We discuss what marine debris is, how it ends up in the ocean, and exactly why it's an issue for sharks. We also discuss the importance of social media and how to incorporate entanglement reports as real data! You can follow Kristian on Twitter @KJParton, and subscribe to his YouTube channel Shark Bytes! This episode was edited by Kaela Shoe Follow Sharkpedia on Instagram and Twitter @SharkpediaPod  Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

This week we jump into stress physiology with expert and PhD Candidate Alex Schoen! With Alex's help, we breakdown her article, "Simulated heatwave and fishing stressors alter corticosteroid and energy balance in neonate blacktip reef shark, Carcharhinus melanopterus" (Schoen et al. 2021). With climate change as an increasing temperature stressor on marine life, and human-influenced impacts such as fishing, it's important we understand how sharks withstand and process this stress to evaluate if they can survive. Get ready to jump into a world of shark stress physiology! You can follow Alex on Twitter @Science_Schoen Follow Sharkpedia on Instagram and Twitter @SharkpediaPod Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

In this episode Meghan and Amani interview Dr. David Shiffman, a marine biologist and conservationist about his publication "Recreational shark fishing in Florida: How research and strategic science communication helped to change policy" (Shiffman 2020). We discuss the complexities of creating policies that are beneficial to all stakeholders involved, the process which Dr. Shiffman went through in order to write a policy that took into account all sides, and how we, as scientists, can become better science communicators. Get ready to jump into the world of policymaking and science communication!

Amani and Meghan introduce who they are, some of their favorite facts, and what to look forward to in the episodes ahead! Get ready to jump into the world of sharks!

SEASON 2 IS HERE!! We are kicking off the season with Jake Jerome, one of Field School's very own Assistant Director of Program Development and Intern Coordinator. What is shark stress? How do you even go about measuring shark stress? What do we see behaviorally, and what does this mean for them physiologically? Learn more this week with shark physiologist Jake Jerome!

This week we breakdown Jake's article, "Integrating reflexes with physiological measures to evaluate coastal shark stress response to capture" (Jerome et al 2017). Want a copy but can't access it? Send us a message on Instagram or Twitter!

Article Summary:
To better understand physiological stress response to capture, Jerome et al. used conventional blood physiology endpoints such as glucose, lactate, and hematocrit, and assessed 5 reflex responses on sandbar sharks, blacktop sharks, great hammerhead sharks, and nurse sharks species after capture. Their objectives were to test for relationships between physiological variables and hooking duration, shark species, and body size, evaluate for relationships between reflex impairments and hook time, species, and body size, and determine if there were any relationships between the physiological parameter and reflex impairments. Physiological stress response varied widely between the 4 species with nurse sharks constantly displaying the lowest levels of physiological disturbance and great hammerheads displaying the highest. They found that lactate was the most consistent and useful indicator for determining stress in all species. This research is especially important for better understanding the physiological response sharks have to being caught either in recreational catch and release fishing or commercial fisheries.

Follow:
You can follow Jake on Twitter and Instagram @jake_jerome14 

Learn more about Jake at Field School at: https://www.getintothefield.com/faculty--staff.html

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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

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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.

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This week on Sharkpedia we interview scientist Jasmin Graham! Jasmin works at Mote Marine Laboratory in Florida, and much of her research helps evaluate the critically endangered small tooth sawfish. We break down Jasmin's article, Large-scale space use of large juvenile and adult small tooth sawfish Pristis pectinata: implications for management. Get ready to learn all about small tooth sawfish movement along the Florida coast!  You can follow Jasmin at @Elasmo_gal on twitter, as well as the organization she co-founded, Minorities In Shark Science, at @MISS_Elasmo and misselasmo.org! This episode was edited by Kaela Shoe Follow Sharkpedia at @SharkpediaPod on Instagram and Twitter Connect with Sharkpedia:  linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

From the Vault - This episode was recorded with Dr. Brit Finucci back in 2022! But.... life happens. We are so excited to finally share this episode with our sharkies! Join us this week to hear about Dr. Finucci's work studying deep sea sharks and their associations with each other! How do you even research deep sea sharks? How many species are there? How do sharks glow in the dark? Find out this and more!

The article we are reviewing with Dr. Finucci is titled, "Aggregations and associations in deep-sea chondrichthyans"

Summary (modified abstract): Group living has been recorded across a diverse range of chondrichthyans, but given the nature of deep sea chondrichthyans, any inferences of social associations have yet to be described. Using a companion preference analysis, aggregating behaviour and associations in deep-sea chondrichthyans (four holocephalans, ten elasmobranchs) were evaluated across class and group size from long-term archived fisheries independent research trawl survey datasets. Results indicated that not all selected species engaged in aggregative behaviour, but those that did suggested patterns of sex- and size-specific associations, which varied with catch density. Adult females were caught most frequently in low densities, and were highly associated with other adult females. Adult males were consistently associated with each other. The nature of associations provides important insight for selective mortality, such as aggregation-targeting fisheries. 

You can follow Dr. Brit Finucci's work on twitter @BritFinucci

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In this weeks episode, Amani and Meghan discuss the article "Triennial migration and philopatry in the critically endangered soupfin shark, Galeogrhinus galeus" with the primary author, Dr. Andrew Nosal! Dr. Nosal discusses how he and his team were able to track soupfin sharks for multiple years and show that females would return every three years to the same location. This migration coincided with their reproduction! Get ready to jump into the world of soupfin sharks! This episode was edited by Kaela Shoe

This week Amani and Meghan chat with shark parasite expert, Dr. Jimmy Bernot! We discuss his publication, "A new species of Psedopandarus Kirtisinghe, 1950 (Copepoda: Siphonostomoatoida: Pandaridae) from sharks of the genus Squalus L. in New Caledonian waters" (Bernot and Boxshall 2017). We chat about what kind of parasites exist on sharks, how they find their shark hosts, how they reproduce, and what it's like to be a shark parasite biologist! Get ready to jump into all things parasites!

This episode was edited by sound engineer Kaela Shoe

Meghan and Amani saw each other in person for the first time in 4 years when they reunited at Field School in Miami, Florida! Together, they spent a week on Research Vessel Garvin performing scientific workups on sharks. Find out about their time in the field together, the cool shark Meghan drew blood from, and more in this episode.

You can learn about Field School by visiting their website www.getintothefield.com.

This episode was edited by Kaela Shoe

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In these bonus episode, we catch up with friend and colleague Jaida Elcock, test our knowledge of sharks with some games, and talk about some of our favorite species! Did you do better than us on these games? Let us know!  You can follow Jaida on Twitter and TikTok @soFISHtication, and Instagram @soFISHtication_ This episode was edited by Kaela Shoe Follow Sharkpedia at @SharkpediaPod on Instagram and Twitter Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

This week we jump into the world of shark competition with Dr. Yannis Papastamatiou! We break down his article, "Spatial separation without territoriality in shark communities" (Papastamatiou et al. 2018). We talk about how to conduct field research in remote areas, combining multiple techniques together (such as telemetry and underwater video footage) to understand shark relationships, and how collaboration for large projects is key! Get ready to jump into the world of shark competition.

You can follow Dr. Papastamatiou on Twitter @Dr_Yannis and Instagram @yannispapastamatiou

Learn more about Dr. Papastamatiou's lab at https://www.peclabfiu.com/

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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 

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Amani and Meghan talk with PhD Candidate, Alex McInturf! Alex studies physiology in basking sharks and salmon at UC Davis, California. With Alex's help, Meghan and Amani review the article, "Are close-following and breaching behaviours by basking sharks at aggregation sites related to courtship?" by Gore et al., (2018). We talk all about their physiology, migrations, aggregations, breeding behaviour, how they jump their HUGE BODIES OUT OF WATER and more! Get ready to jump into the world of basking sharks!

Juvenile shark presence in an area does NOT mean that that area is a shark pupping or nursery ground. So how do we know what actually makes a shark nursery ground? What even IS a nursery ground? Is it different than a pupping ground? Why does any of this matter? Find out this week with our special guest, Dr. Michelle Heupel!

Dr. Heupel joins us to talk about her article, "Shark nursery areas: concepts, definition, characterization and assumptions" (Heupel et al. 2007).

Article Summary:

Shark nursery habitats are critical areas that sharks rely on for their early life stages. However, the criteria defining shark nursery grounds has been inconsistent through history. These inconsistencies can make management strategies more difficult, as some definitions could imply that all coastal areas are nursery habitats, and other definitions are insufficient. In this study, Heupel et al. propose a new definition for shark nursery habitats that will more accurately pinpoint Essential Fish Habitat. That definition is: (1) sharks are more commonly encountered in the area than other areas; (2) sharks have a tendency to remain or return for extended periods; and (3) the area or habitat is repeatedly used across years. These criteria make the definition of shark nursery areas more compatible with those for other aquatic species. The improved definition of this concept will provide more valuable information for fisheries managers and shark biologists.

You can follow Dr. Heupel @michelleheupel on instagram, and follow her work on Research Gate and Google Scholar!

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That's right, Meghan and Amani are wrapping up Season 1 of Sharkpedia! Jump in for an episode recapping how the podcast has grown, some of our favorite parts of Season 1, and things to look forward to in Season 2! Don't worry - We'll be back in just a few short weeks with new guests and papers to dive into! 

Please don't forget to rate and review Sharkpedia wherever you get your podcasts so that other sharkies can find us for Season 2!

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Happy New Year Sharkies! Join us as we talk about why we took such a long hiatus, our favorite shark experiences of 2023, and what's to come for Sharkpedia in 2024.

Did you know that shark body form can change as they grow? Why does that happen? Why does it matter? Find out this week on our episode investigating these questions of bull sharks with Joel Gayford!

Title: Ontogenetic Shifts in body form in the bull shark Carcharhinus leucas

Summary: It is believed that body growth is strongly correlated to trophic and spatial ecology through ontogeny, or as a shark ages. Gayford et al. used bull sharks as their study species to better understand morphological growth at many different locations along a shark's body. They found shifts in functional demands across the body through ontogeny, seemingly driven by selective pressures relating to trophic and spatial ecology. They also found significant differences in scaling trends between life stages and sexes. They ultimately discuss the implications of their results for existing ecomorphological hypotheses and provide a robust study to add to much needed research in this area. You can follow Joel Gayford @sharkmeasurements on instagram

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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!

This week we jump into the world of cookiecutter sharks with expert Dr. Aaron Carlisle! We break down his article, "Integrating multiple chemical tracers to elucidate the diet and habitat of Cookiecutter Sharks" (Carlisle et al. 2021). We discuss the various techniques Carlisle and colleagues used to uncover that cookiecutter sharks eat a much more varied diet than you might expect! We also learn about new biochemical tracer techniques that made this research possible. Learn how Dr. Carlisle tackled this, and buckle up for a rather PG-13 field story at the end! Get ready to jump into the world of cookiecutter sharks!

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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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This week we are joined by Dr. Ana Martins, a postdoctoral researcher at Dalhousie University studying the shark meat trade. The shark fin and meat trade is a common media topic but angler knowledge and opinions seem to be rarely incorporated into these discussions. In her home country of Brazil, Dr. Martins utilized angler knowledge to uncover trends in the shark meat trade. Listen through the episode until the end for a rather fishy field story which will have you laughing in your seat. 

The article which is the base of our discussion this week is, "Analysis of the supply chain and conservations status of sharks (Elasmobranchii: Superorder Selachimopha) based on fisher knowledge"

Article Summary:

Increasing fishing effort has caused declines in shark populations worldwide. Understanding biological and ecological characteristics of sharks is essential to effectively implement management measures, but to fully understand drivers of fishing pressure social factors must be considered through multidisciplinary and integrated approaches. Martins et al. aimed to use fisher and trader knowledge to describe the shark catch and product supply chain in Northeastern Brazil, and evaluate perceptions regarding the regional conservation status of shark species. They had 3 main objectives: identify the presence of a supply chain of two shark products (meat and fins), (2) describe the supply chain for each product, and (3) qualitatively evaluate fisher and trader perceptions regarding the regional conservation status of shark species. Several threatened shark species were reportedly often captured off shore and traded at local markets. This reported and observed harvest breaches current Brazilian environmental laws. Fishing communities are aware of population declines of several shark species, but rarely take action to avoid capture of sharks. The continuing capture of sharks is mainly due to a lack of knowledge of environmental laws, lack of enforcement by responsible authorities, and difficulties encountered by fishers in finding alternative income streams. National and regional conservation measures are immediately required to reduce overfishing on shark populations in Northeastern Brazil. Social and economic improvements for poor fishing communities must also be implemented to achieve sustainable fisheries.

Follow Dr. Ana Martins on Twitter @martins_apb

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This week Amani and Meghan chat with Dr. Mark Royer about the swimming behavior of scalloped hammerhead sharks! With Dr. Royer's help, Amani and Meghan review his article "Scalloped hammerhead sharks swim on their side with diel shifts in roll magnitude and periodicity" (Royer et al. 2020). Did you know scalloped hammerhead sharks swim on their side to save energy? Do you know what a tri-axial accelerometer shark tag is? Find out about this and so much more on this week's episode! This episode was edited by Kaela Shoe Follow Sharkpedia on Instagram and Twitter @SharkpediaPod Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

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 alexandra.mcinturf@oregonstate.edu

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This week Amani and Meghan discuss sand tiger sharks from the Eocene with Dr. Sora Kim! We explore the ecology and environment of sand tiger sharks during the Eocene, and can even explore climate change during the Eocene using sand tiger teeth fossils! This discussion was guided around Dr. Sora Kim's publication, "Probing the Ecology and Climate of the Eocene Southern Ocean With Sand Tiger Sharks Striatolamia macrota". Get ready to learn about some incredible things we can learn about the climate during the Eocene using stable isotope analysis of teeth from extinct sand tiger sharks!  You can connect with Dr. Sora Kim on Twitter @SoraLKim This episode was edited by Kaela Shoe Follow Sharkpedia at @SharkpediaPod on Instagram and Twitter Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

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

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This week we join Kate McKinnon as Miss Frizzle on the Magic School Bus to explore shark noses up close!

Just kidding. But we do have shark-nose-specialist Dr. Lauren Simonitis! We break down her article Microstructure of the BonnetHead Shark (Sphyrna tiburo) Olfactory Rosette. (Simonitis & Marshall 2022). Learn all you could need to know about shark noses and more! 

Summary: The weird shape of hammerhead sharks means that their naris or noses are also weirdly shaped. Previous research has shown that the flow of water in hammerhead noses has a complex structure that changes the pressure and therefore changes the velocity of water in the nose itself. Simonitis et al., aim to describe the microstructure of the olfactory rosette of the bonnethead shark , sphyrna tiburo, and investigate differences in the individual lamellae themselves within the rosette. Specifically they looked at the degree of secondary folding, percent sensory area, and the relative surface area of the lamellae. This is the first time the olfactory nerve layer has been visually tracked through a shark lamella. They found that olfactory lamellae in areas of the olfactory organ that experience faster water flow, have a larger percentage of sensory area and more secondary folds compared to those exposed to lower water velocities. Their findings imply that there may be less sensitive portions along the rosette. Future work should look at flow and sensitivity inside a shark's nose with this information in mind.

Follow Dr. Simonitis on Twitter and Instagram @OceanExplauren

Follow some of Dr. Simonitis' work on Twitter and Instagram @MISS_Elasmo

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This week we go abroad to Sri Lanka with conservation expert Akshay Tanna! We discuss his article, "Where have all the sawfishes gone? Perspectives on declines of these Critically Endangered species in Sri Lanka" by Tanna et al. 2021. Akshay and his colleagues use critical historical knowledge from local fishers. This knowledge is often referred to as "Fishers Ecological Knowledge", or FEK. This knowledge that Tanna and colleagues gathered allows them to identify 2 distinct species of sawfishes that historically visited Sri Lanka, and evaluate the specific point in history when sawfish sightings drastically decreased. This critical knowledge that Tanna and colleagues at Blue Resources Trust have conducted is just the beginning of the many incredible conservation evaluations they are leading in Sri Lanka.  Learn more about the conservation efforts in Sri Lanka at blueresources.org Follow Blue Resources on Twitter @blue_resources and on Instagram @blueresources Follow Sharkpedia on Instagram and Twitter @SharkpediaPod Connect with Sharkpedia: linktr.ee/sharkpediapod Email: thesharkpediapodcast@gmail.com

This week we talk with Dr. Haley Dolton about how she studied the physiology of basking sharks in Ireland! This is no small feat.

We read Dr. Dolton's article, "Regional endothermic traits in planktivorous basking sharks Cetohinus maximus"

Article Summary: The majority of sharks are classified as cold-blooded or ectotherms. Sharks are constantly battling heat loss to the surrounding water. To combat this, some fast-swimming apex species are classified as regional endotherms, having uncommon physiological traits such as elevated internal body temperatures, centralized red muscle, and thick-walled hearts. Within the order Lamniformes, housing the only regionally endothermic sharks, you can find the basking shark which is a large, filter-feeding planktivorous species. Previous research has led to the conclusion that basking sharks are ectothermic. To investigate this, Dolton et al. collected muscle samples and measured the internal temperature of basking sharks finding that they displayed the traits previously stated. Their research leads to the finding that basking sharks may not be correctly classified as an ectotherm, which is a surprising find!

You can follow Dr. Dolton @HaleyDolton on Instagram and Twitter!

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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

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