SCUBA News - #293 - December 2024

SCUBA News ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SCUBA News (ISSN 1476-8011) Issue 293 - December 2024 https://www.scubatravel.co.uk ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Welcome to December's SCUBA News. Our compliments of the season to you, and a seasonal creature of the month - the Christmas Island Red Crab. Any questions and comments to news@scubatravel.co.uk, I look forward to hearing from you. Contents: What's new at SCUBA Travel? Creature of the month: Christmas Island Red Crab 5 Liveaboard diving deals - save 35% Diving news from around the World You can download this SCUBA News issue as a pdf. What's New at SCUBA Travel?

Best places to dive in January Whale sharks, manta rays, hammerhead sharks...if megafauna floats your boat January is a great time to go diving. LEARN MORE… Wreck diving in the Mediterranean The Mediterranean is a wreck diver's paradise, offering a blend of history, marine biodiversity and exceptional diving conditions. Every wreck tells a story. READ MORE… Scuba diving best selling books of 2024 SCUBA Travel are pleased to release the list of our best selling SCUBA books in 2024. There have been some great books published this year which have made the list, plus some old favourites. SEE WHICH…

5 Fantastic Liveaboard Deals - Save up to 35% More great liveaboard diving deals, to some of the best diving destinations in the world, specially selected for us by Divebooker.com, the liveaboard specialists. Elegante, Djibouti, SAVE 23% but hurry, ends 4 January. See the famous Djibouti whale sharks. Price from GBP 876. More Info or Book Galaxy Diver II, Galapagos, SAVE 35%, Price from USD 4615. World-class diving adventure amidst a breathtaking array of marine life, including sharks, whales, manta rays, turtles, penguins, iguanas and sea lions. More Info or Book Duyungbaru, Komodo, 10% off my all-time favourite liveaboard which caters to just 8 divers at some of the best diving in the world. Duyungbaru is Indonesian for mermaid. More Info or Book Carpe Novo, Maldives, SAVE 10%. Price from just USD $2610 per trip per person next year. More Info or Book Snefro Pearl, Red Sea , From just Euro 479. One of the smaller liveaboards in the Red Sea visiting Ras Mohamed and the famous Thistlegorm, one of the best wrecks in the world. More Info or Book Creature of the month: Christmas Island Red Crab At the start of the wet season, between October and December, the unique Christmas Island Red Crabs start their annual migration. Forty million of them pack their bags and travel to the coast from their rain forest homes. The first to set off are the males living furthest inland. They are joined by more and more crabs as the march progresses towards the sea. Christmas Island Red Crab with eggs – photo credit: Christopher Andrew Bray, CC-BY-SA-4.0 Christmas Island is nearly 1500 miles away from its Australian parent, and is closer to Indonesia. The diving is great there, but it's the crabs that attract people. Christmas Islanders have built bridges to help the migrating Red Crabs – photo credit: Alex Cairns, CC-BY-SA-4.0 The crabs make the journey to spawn – dropping their eggs into the sea. This happens before sunrise on a spring tide during the last quarter of the moon. The crabs walk in straight lines, but not to the nearest coast: most travel towards the northwest shore. They can walk over 14 km a day, but 680 m is more common. When rains are late the crabs rush to seaside. If not then they linger for up to a week on the way to feed. This behaviour implies that the crabs are able to judge how far away they are from the shore during the migration. When they reach the coast, after a dip in the sea the males dig a burrow for mating. After mating the males again immerse themselves in the water before the long walk home. The females stay in the burrows, brooding their eggs for a couple of weeks. When the time is right, at high tide they jettison their eggs into the sea then make the return trip. Fernando Perez Peralta The eggs immediately hatch into larvae which grow into tiny animals called megalopae. After about a month these emerge from the ocean and moult into baby crabs. Four years later these crabs will repeat the migration and the cycle begins again. Christmas Island Red Crab megalop – photo credit: Christopher Andrew Bray, CC-BY-SA-4.0 Some years hardly any baby crabs make it out of the sea. Whale sharks and manta rays feast on them and few escape. Every so often though massive numbers survive. Photo credit: Tim Nicholson Phylum: Arthropoda > Sub-Phylum: Crustacea > Class: Malacostraca > Subclass: Eumalacostraca > Order: Decapoda > Species: Gecarcoidea natalis Further Reading and References Agnieszka M. Adamczewska and Stephen Morris Ecology and Behavior of Gecarcoidea natalis, the Christmas Island Red Crab, During the Annual Breeding Migration, The Biological Bulletin 200, no.3 (Jun 2001). Red crabs and migration | Christmas Island National Park, Australian Government Diving news from around the World Scientists name 20 North Atlantic right whales, welcome Swallowtail, Frisbee, Polaris et al The naming is an annual tradition that helps researchers identify the critically endangered animals in the wild as they see them. Whale-ship collision risk mapped across Earth's oceans 92% of whale habitats overlap with shipping routes Illegal feeding of sharks puts divers at risk of attack Cayman's Department of Environment have issued a warning about the dangers associated with feeding sharks. Researchers tag first Mediterranean shortfin mako shark These sharks are critically endangered not only in the Mediterranean but also globally. As Thailand's blue swimming crabs decline, crab banks offer a sustainable solution Egg-bearing females are nurtured in the crab banks, with their hatchlings later released into a secure marine site. How military sonar impacts dolphin social dynamics Sound is essential for communication and sensing in dolphins, so anything that disrupts it could be bad news. Fish Have a Brain Microbiome. Could Humans Have One Too? But scientists have long assumed that bacteria can't survive in the human brain, but a brain microbiome can and does exist in healthy vertebrates - fish, specifically. Salmon hats back in fashion for orcas A fad last seen in the 1980s, orcas are again wearing dead salmon as hats.

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