News
Giant manta rays found to be predators of the deep ocean
A new scientific study by the Marine Megafauna Foundation (MMF), the University of Queensland (UQ) and Proyecto Mantas Ecuador has been published in Royal Society Open Science today, providing novel insights into the food sources of giant manta rays found in the eastern equatorial Pacific.
The giant manta ray (Manta birostris) is a filter-feeding and highly migratory marine species found in tropical and temperate waters worldwide. The large majority of existing information about the species’ diet is based on observational data limited to feeding activities at the sea surface during daylight at well-known aggregation sites.
This new study focused on Isla de la Plata, an island off Ecuador, which seasonally hosts the largest known aggregation of giant manta rays in the world. Manta ray muscle and surface zooplankton were examined through stable isotope analysis, and revealed that the species’ dietary intake largely comes from the mesopelagic zone (200 to 1,000 meters below the ocean surface) rather than from surface zooplankton as previously thought.
MMF’s manta ray researcher Katherine Burgess, who authored this study as part of her PhD project at the University of Queensland, commented: “Manta rays are one of the most iconic marine animals, yet we still know very little about their feeding habits. The study reports much-needed information on the diet of this elusive species.”
“We studied the giant manta rays’ diet using biochemical tests, such as stable isotope analysis, which work on the ‘you are what you eat’ paradigm. These tests can determine what animals have been eating by examining a piece of tissue from a muscle biopsy from a free-swimming animal,” she added.
Professor Anthony Richardson, a scientist with UQ’s School of Mathematics and Physics and the CSIRO’s Oceans and Atmosphere Flagship, said: “The research found an average 27 per cent of the giant manta rays’ diet comes from surface zooplankton and 73 per cent from mesopelagic sources including fish from 200m to 1,000m below the ocean surface.”
“The deep ocean is the next frontier for open ocean fisheries, and we are only just realizing the potential reliance on this zone by threatened marine megafauna,” he added.
Giant mantas are known to dive to depths of over 1,000 meters making it difficult to study their feeding ecology. To determine the diet of a fish, researchers normally examine its stomach contents. However, this is usually a distressing or lethal procedure and would not be appropriate considering global manta ray populations have been in drastic decline due to anthropogenic threats such as targeted fishing or bycatch, pollution and habitat destruction.
Both species of Manta – the giant manta ray (Manta birostris) and reef manta ray (Manta alfredi) – are listed as ‘vulnerable to extinction’ on the IUCN Red List of Threatened Species. To date, manta rays are formally protected in Ecuador, Peru, New Zealand, the USA (Florida, Hawaii and Flower Garden Banks), Guam, Maldives, Yap, Indonesia, the Philippines and Mexico only. Filling the knowledge gaps on manta ray feeding ecology is crucial for the identification of critical habitats and aggregation sites, which are vital for developing effective conservation measures for these species.
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.
Blogs
EXCLUSIVE: Jeff Goodman interviews Mark Spiers, CEO of New Scuba Diving Training Agency NovoScuba
In a video recorded exclusively for Scubaverse.com, Jeff Goodman interviews Mark Spiers, CEO of new scuba diving training agency NovoScuba.
Find out more about NovoScuba at www.novoscuba.com.
-
News3 months ago
Capturing Critters in Lembeh Underwater Photography Workshop 2024: Event Roundup
-
Marine Life & Conservation Blogs3 months ago
Creature Feature: Swell Sharks
-
Blogs2 months ago
Murex Resorts: Passport to Paradise!
-
Gear Reviews3 weeks ago
GEAR REVIEW – Revolutionising Diving Comfort: The Sharkskin T2 Chillproof Suit
-
Blogs2 months ago
Diver Discovering Whale Skeletons Beneath Ice Judged World’s Best Underwater Photograph
-
Gear Reviews3 months ago
Gear Review: Oceanic+ Dive Housing for iPhone
-
News2 months ago
PADI Teams Up with Wellness Brand Neuro to Drive Ocean Change and Create a Blue State of Mind
-
Marine Life & Conservation2 months ago
Save the Manatee Club launches brand new webcams at Silver Springs State Park, Florida