News
The Great Eggcase Hunt goes underwater!
Since 2003, the Great Eggcase Hunt (GEH) has been encouraging the public to hunt for shark, skate and ray eggcases that have washed up along the UK’s coastline. Despite these records providing a remarkable amount of information on the distribution of egg-laying (oviparous) elasmobranchs, eggcases that are washed up on the shoreline do not always provide a true indication of where they were laid, as ocean currents can carry them some distance. Eggcases Underwater is a spin off from the GEH project, providing a new approach to eggcase hunting.
There are 13 different shark, skate and ray species that are known to commonly lay their eggs around the British Isles, 10 species of skates/rays and 3 species of sharks. These species produce a single embryo inside an eggcase capsule (often called a ‘mermaid’s purse’) and deposit this on the seabed or attach it to seaweed. Once deposited, the shark, skate or ray will take up to 12 months to fully develop inside this capsule.
The eggcases from different species are a variety of sizes and shapes. The two more commonly found shark eggcases feature curled tendrils that allow the female to attach the capsule to a macroalgae as it develops. While a feature of skate/ray eggcases includes a distinctive horn extending from each corner of the rectangular case, allowing the skate/ray to lay its egg on the seabed concealed by rocks, sand, and gravel. When first laid the catshark eggcases in particular are easily distinguishable by their light colour and transparency. Overtime they become camouflaged by fouling species and are often difficult to spot.
The distribution of many shark, skate and ray species is changing and for many species declining. Eggcases Underwater needs your help to improve our knowledge of the distribution of oviparous elasmobranchs, their egglaying grounds, and the types of substrates that different species lay on. If you see an eggcase underwater, please take a note of the approximate location of your sighting and, if possible, take a photograph. You can then record details of your eggcase via the online recording form at www.sharktrust.org/recordyoureggcase or by downloading the app (Android/iOS). Your sightings can help improve the Shark Trust’s understanding of oviparous sharks, skates and rays, which could in turn benefit the conservation, management and protection for these species and their egglaying grounds!
Author: Tegan Consol
For more information, please visit www.sharktrust.org/en/eggcases_underwater.
Marine Life & Conservation Blogs
Book Review: Shells of the World
Shells of the World: A Natural History by M.G. Harasewych
Shells of the world is a guide to the world of marine, shelled molluscs. And what a varied and interesting world it is. Some of my favourite things to find on a dive are detailed in this book, including disco clams (or Electric File Clams as they are correctly names), the cephalopods, giant clams and sea hares. There are also many on my wish list, top of which is the Nautilus.
Each chapter provides a detailed description of the species, along with beautiful images. You can dive deeper and discover where they live, both with global distribution and the habitat they prefer. Learn about their diet, reproduction and diversity.
Having dipped in and out of this lovely book over the past few weeks, it has inspired me to learn more about this group of animals that we see on most divers, wherever we are in the world. Some of the shells are incredibly intricate and beautiful. I have always agreed with never collecting, or touching, marine life. The description of a certain set of cone shells should be a warning to those that are happy to pick up marine life! One of the cone shells has a local name called the cigarette snail. Why? Because once the venom is in your system from this animal, you only have time to smoke one cigarette before the affects of the venom are fatal!
What the publisher says:
Mollusks are invertebrate animals with a remarkable natural history and a rich fossil record, and their shells are prized for their breathtaking variety and exquisite beauty. Shells of the World provides a wide-ranging look at the incredible diversity of marine mollusks. An informative introduction outlines the lineages covered, followed by a directory section, split into classes, that profiles a broad selection of different taxa to give a sense of their sheer numbers and variety.
- Features hundreds of beautiful color photos, depicting both the live animals and their shells
- Discusses mollusk evolution, anatomy, life cycles, behavior, and ecology
- Describes unique characteristics, distribution, habitat, and size
- Provides valuable insights into the conservation of the world’s marine mollusks
- Ideal for malacologists and shell collectors everywhere
About the Author:
M. G. Harasewych is research zoologist emeritus and former curator in the Department of Invertebrate Zoology at the Smithsonian Institution’s National Museum of Natural History. A fellow of the American Association for the Advancement of Science, he is the author (with Fabio Moretzsohn) of The Book of Shells: A Life-Size Guide to Identifying and Classifying Six Hundred Seashells.
Book Details
Publisher: Princeton University Press
Hardcover
Price: £25
ISBN: 9780691248271
Published: 9th April, 2024
Gear News
Go anywhere with Stahlsac
Stahlsac dive bags and travel luggage are built for our community of divers, surfers, kayakers and outdoor explorers who need bags that are constructed with durability, toughness, and the highest quality the industry has ever seen. We were founded by one man determined to build better watersports and dive bags, and today, that mission is carried on by many. Adventure doesn’t just present itself; it requires discovery. When we design dive bags, we make sure they are tough enough for you to explore in all conditions—warm and cold, wet and dry—to the nearest and farthest reaches of the earth. And for those times you want to push the boundaries of adventure, Stahlsac dive bags make sure you can truly GO ANYWHERE.
Abyss Duffels
Made to be your partner-in-crime on every adventure, Stahlsac’s Abyss Duffels protects your gear from Mother Nature’s worst. Tough and 100% waterproof with double-TPU nylon material that shrugs off daily wear-and-tear, and RF-welded seams further boost the bag’s potential for lifelong exploring. Get Wet. Get Lost. Go Anywhere with Abyss.
- A weatherproof duffel for trips, travel, and adventure
- Ultra-durable double-TPU nylon protects your gear
- Material repels water and keeps your equipment dry
- RF-welded seams are flush, tough, and waterproof
- Removable straps transform duffel into backpack
- Zippered internal stow compartments carry essentials
- External zippered flap is easy to open and close
- Welded external handles make transporting a breeze
Panama Mesh Backpack
The most copied design in scuba diving, the Stahlsac Panama Mesh Backpack is the “original” design and features two high-density foam padded shoulder straps, extra durable polyester mesh, duffel bag handles and our unique zippered dry pocket inside that combines with a wet pocket outside. The bottom’s built from reinforced 18-gauge PVC nylon to combat the wear and tear of your active coastal lifestyle, and, as a bonus in every bag, we supply a 12″ x 12″ mesh drawstring satchel for extra stowing utility. Pack up your beach kit and go.
- Density foam padded shoulder straps
- Outside wet/dry pockets
- 2 Carry handles
- Tough, snag-resistant polyester mesh
- Reinforced PVC bottom
For more information about Stahlsac bags, visit www.stahlsac.com/dive-bags.
Sea & Sea is the home of Stahlsac and other leading diving brands in the UK.
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