8/3/17 Oyster Update – Word of Mouth

 

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Oysterman on the Chesapeake – Photo Credit: Robert De Gast

Thanks in part to the generosity of donors to my crowdfunding campaign, I’ve started the process of listening to fishermen and oystermen in St. Augustine and nearby!

In order to capture different ideas and access multiple types of people, I am using a technique commonly called snowball sampling. Every time I interview someone, either formally or informally, I ask them who else I should be talking to. The idea is that eventually there will be enough overlap in the answers you’re getting that you know you are starting to capture the population you’re interested in.  This approach is known to have some drawbacks in that it can be challenging to not talk exclusively to people who think similarly to one another. However, when your target populations are small, this method may be the most effective way of accessing them.

While not giving too much away, I’ll also say that I’m already noticing some common themes in the answers I’m hearing to my questions which is exciting. I’m learning interesting details about what fishermen and oystermen look for in reefs. One of the most enjoyable aspects however, is the extra details that are being shared, the personal history and anecdotes people are peppering in with their responses. The experience of local oyster roasts has been mentioned, with each telling rich in explanation about methods of cooking and cultural significance. Stories about growing up on the local waterways abound as well. This kind of research is affording me a chance to really root around and understand the complexity of ways these groups are identifying with this resource, and I’m excited to have the opportunity.

Keep an eye on my blog for continued updates on all things oyster!

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Demystifying the Narwhal’s Tusk

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Photo Credit: National Geographic

Yet again drones have proved an invaluable instrument for new discoveries, especially when it comes to observing marine mammal behavior (see my past post: Whale Tales – Current Cetacean Communiqués).  The subject in question this time is the strange and elusive Narwhal.

Humans have valued Narwhal tusks for centuries, perceiving them as a cure for a number of medical ailments including epilepsy and poisoning, a practice which is still alive and well in Japan. Inuits still carry on the tradition of culling narwhal for subsistence and often used the tusks for carving. However, we have had little knowledge about the value of the tusk to the animal itself until recent years. More current research and observation suggests the tusks of narwhals function in multiple capacities.

The edited footage above conveniently highlights moments where individual narwhals stun passing cod with a solid tap of their tusk. It’s an interesting hunting method, but one that is rivaled by other examples in the marine world. Many species immobilize their prey; some, like sailfish, use similar techniques, while others may use contrasting tools. Electric Rays and eels shock their quarry, while pistol shrimp use high-speed cavitation bubbles to daze their targets. Archer fish knock their dinner out of overlying branches by spitting a stream of water at them.

The purpose of the narwhal’s tusk likely doesn’t stop at clubbing unwitting prey. The absence of an enamel coating on their tusk supports the idea that these animals might be using them in a sensory capacity, allowing the specialized tooth to come into contact with surrounding water masses to detect environmental changes such as salinity and temperature, as well as chemical cues in the water associated with food and mates. Pairing this awareness of their surroundings with highly directional echolocation also allows them to find sometime slim openings in Arctic ice coverage where they can surface and breath as needed.

However, these animals may still suffer catastrophic events living in the extremes they do. Pods of narwhals occasionally suffer entrapments when rapidly shifting weather conditions cause unexpected freezing over potential air holes leading to open water. Kristin Laidre, a researcher at University of Washington’s Polar Science Center, noticed the frequency and timing of those events may be changing with recent shifts in Arctic climate. This, paired with a variety of additional stressors to the whales’ habitat, is the focus of one her current research projects examining the behavioral ecology of narwhals in a changing Arctic. She and other researchers have tagged the animals on multiple occasions in Canada’s Baffin Bay to track their movement, the depth of their dives, and associated water temperatures. As it turns out the temperature data has proved useful to other scientists interested in climatology data. Laidre is soon hoping to once again utilize the oceanographic power of narwhals, this time in Greenland.

Speck of Science 2/19/17 – Denuding Geckos

 

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Photo Credit: A. Anker

A week and half ago multiple science news outlets reported on the publication of a study that described a new species of Geckolepis geckos, a bizarre genus that goes by the more common moniker of “fish-scale” geckos. They appear to be relatively unique to the Comoros Islands and Madagascar, locations that harbor other fascinating endemic species (restricted to a certain region), a fact which can largely be attributed to island isolation.

These lizards are sheathed in a layer of vibrant scales that they jettison quickly in response to perceived predatory threats. Mark Scherz, the PhD candidate who lead-authors the study, experienced significant challenges trying to collect fully-covered specimens of what would later be identified as Geckolepis megalepis. The gecko loses skin with scales, and much resembles a naked baby mouse after the process. As the study notes, “The new species has the largest known body scales of any gecko (both relatively and absolutely), which come off with exceptional ease.”

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Photo credit: F Glaw

This quality of Genus Geckolepis to lose then regenerate scales is suggested to have applications in human medicine with regards to tissue recovery. In addition, geckos have been studied for other enviable qualities including their ability to adhere to vertical surfaces with ease.

 

 

Speck of Science 2/7/17 – Shark Find in Belize

FIU researcher Demian Chapman and a possible new species of Bonnethead. Source: FIU 

A new species of Bonnethead has been described in Belize by FIU researcher Demian Chapman, thus the scenario of a single widespread species in that region now becomes the story of one or more species with overlapping ranges. The discovery was made after analyzing a snippet of the shark’s genome.

DNA analysis has allowed a much more nuanced perspective on species-level differences beyond the physical characteristics that were once the focus of classically-trained taxonomists. Now scientists are able to classify variance on a genetic level and have refined the technique. Now researchers use a method called DNA barcoding, which needs to examine just a small portion of an animal’s genomic sequence, and is often compared to scanning groceries at your supermarket’s checkout line. Large-scale efforts to catalog and archive these genetic identifiers, such as Barcode of Life, make this data widely accessible.


In addition, this finding was part of a larger initiative, called Finprint, focused on filling in data gaps concerning sharks, fins, and rays – all of which constitute a group of cartilaginous fish known as elasmobranchs. Finprint uses baited remote underwater video (BRUV) as one of their primary tools for studying these creatures. Much of their work appears to be focused on their spatial distribution, identifying regions that could lead to conflict with other uses such as fishing or areas that can be marked as candidates for protection.

 

Speck of Science 1/24/16 – Bees of the Seas

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Many of nature’s means of doing business on land has aquatic parallels. Seagrasses produce seeds and pollen the same way as terrestrial grasses do. However, there are certainly some differences. The pollen grains of seagrasses dwarf their land-based counterparts at almost 50 times larger, and the physics of the water in which pollination occurs certainly follows rules vastly different than those air currents.

Scientists have been postulating for some time about how marine plants get the job done in such a different environment, evident in this 1976 abstract for a submission in Letters to Nature.  Many aquatic plants may reproduce by variations of self-cloning where a sexual partner is not needed to give rise to new individuals. Sea grasses often dabble in a little of both worlds, as both have their evolutionary advantages. Cloning, often referred to more specifically as vegetative propagation in plants, allows underwater flora to quickly take up real estate without expending as many resources.  However, sexual reproduction confers the benefits of genetic variation and adaptability into their populations.

Initially, it was suggested water bore the primary burden of transporting pollen grains from male to female seagrass plants. However, in 2009, a team of researchers from National Autonomous University of Mexico led by  Brigitta van Tussenbroek observed small invertebrate crustaceans visiting turtlegrass (Thalassia testudinum) flowers in a manner that reminded them of terrestrial bees.

To explore whether or not these small creatures had the capacity to truly serve as pollinators, they moved their exploration in the controlled setting of a laboratory. They put turtlegrass and pollinators in tanks sans current, and monitored the movement of pollen grains as well as successful instances of pollination. Both successfully occurred in tanks where crustaceans had been added, but not in tanks where the animals were absent. The research team coined a new term, zoobenthophilous pollination, to describe the marine process they observed.

Seagrasses are vital to human wellbeing in ways similar to oyster reefs, coral reefs, and mangroves, and provide a wealth of services to the environments they thrive in. They are an important food source for manatees, dugongs, turtles, and other creatures. Their root systems stabilizes sea floors. They may serve as nursery grounds for minuscule juvenile fish needing protection from predators. But seagrasses have seen vast decline worldwide, in what could be called a global crisis. Now that we are learning seagrass survival may also have dependence on pollinators, we can only hope we do a better job of conserving these little sea bees than we have their terrestrial counterparts.

Speck of Science 8/17/16 – The Greenland Shark abides

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Source: Ocean Treasures Memorial Library

Several news outlets this week have justifiably made a big deal about the Greenland Shark. Recent research suggests these lumbering giants are now the record holder for the longest lived vertebrates we are aware of. This knocks the Bowhead whale from first place, whose age-determination story is fascinating in its own right, bolstered by the presence of an antique eskimo harpoon point.

Often sharks have been aged through examining growth bands present in vertebrae, however Greenland sharks have softer vertebrae that make this challenging. Additionally, due to challenges in reading these rings as sharks age, as well as possible disconnects between growth rate and age, radiocarbon dating has been joining the toolbox for determining fish longevity.  This study used the method with the sharks’ eye lenses.

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These sharks may take up to 150 years to reach sexual maturity, making their population vulnerable if too many individuals are culled before reproducing. They are also bizarrely prone to parasitism by a strangely-elongate copepod (most look more shrimp or lobster-like) that attaches to their eyeball and ultimately causes a march towards blindness. Only 1% of the 1500 sharks in a study concerning infection rates were parasite-free. 85% are afflicted in both eyes. However, due to their reliance on a keen sense of smell, rather than sight, for hunting, it has been suggested that the sharks may actually benefit from the copepod acting as small visible lures that interest nearby prey. However, Dr. George Benz of Middle Tennessee State University with expertise in shark and ray parasites, doubts this theory, instead favoring the idea that Greenland sharks may instead be ambush hunters, taking their targets instead through the element of surprise.

Speck of Science 8/15/16 – Nat Geo Writes About Pooping Comb Jellies

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Still from Ryan M. Bolton 2016 video: https://www.youtube.com/watch?v=weeFO6kLu5o

Lest you think National Geographic is losing their edge, the reason why ctenophores (the phylum to which comb jellies belong) defecating is a big deal is because it was thought this group of creatures had a single opening for both feeding and excreting. University of Miami researcher William Brown debuted videos at the March 2016 Ctenopolooza gathering at the Whitney Lab in St. Augustine (where I’ve done much of my own dissertation field and lab work) that prove otherwise. One of the peculiar videos is featured partway through Nat Geo’s article here. Science writes about the find as well.

One of the most interesting aspects of this find is questions regarding the evolutionary history of gut development. It was thought to be a pretty straight forward pathway from one opening to two. However, because comb jellies evolved before other organisms that still have a single opening, such as sponges, things are looking slightly more interesting. Perhaps ctenophores branched off, and smartly evolved a more complex gut tract independent of these organisms. Or, perhaps some of these single-orificed organisms started with two but lost one over time – similar to the story of some marine mammals that long ago left the sea to become land-dwellers, only to ultimately return again.