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Images Reveal a Previously Unexplored Deep Sea Trench

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Scientists have had the first look at the life that thrives in one of the deepest spots in the ocean.

An expedition to the unexplored New Hebrides trench in the Pacific has revealed that cusk eels and crustaceans teem more than 7,000m (23,000ft) down.

The team used an unmanned lander fitted with cameras to film the deep-sea creatures.

The scientists said the ecology of this trench differed with other regions of the deep that had been studied.

“We’re starting to find out that what happens at one trench doesn’t necessarily represent what happens in all the trenches,” said Dr Alan Jamieson, from Oceanlab at the University of Aberdeen, UK, who carried out the expedition with the National Institute of Water and Atmospheric Research in New Zealand.

Trench 2

There are more than 30 deep-sea trenches around the world, and most of these narrow fissures in the seafloor lie in the Pacific Ocean.

Until this expedition, the depths of New Hebrides trench, which sits about 1,500km (1,000 miles) north of New Zealand, had not been explored.

The footage captured by the team during the 30-day voyage at the end of 2013 shows large, grey cusk eels, some 1m-long, chomping on the bait that had been attached to the lander.

The fish mingle with large, bright red prawns scrabbling around on the sandy seabed, which plunges down to 7,200m at its deepest point.

They also spotted eel pouts, arrow-tooth eels and thousands of smaller crustaceans, some of which were collected and brought back to the surface.

However, the team noted marked differences when they compared this trench with others they have studied, which include the Japan trench, the Izu-Bonin trench and the Kermadec among others.

Dr Jamieson said: “The surprising thing was that there was a complete and utter lack of one of the most common deep sea fish we would expect to see. Anywhere else around the Pacific Rim, around the trenches we’ve looked at, you see a lot of grenadiers – they are quite a conspicuous part of the deep-sea community. But when we went to the New Hebrides trench, we didn’t see a single one.

Trench 3“But what we did see was a fish called the cusk eel. These turn up elsewhere but in very, very low numbers. But around the New Hebrides trench, these – and the prawns – were all that we saw.”

There was also an absence of snail fish, a small pink fish usually seen in the deepest depths of ocean trenches.

The researchers believe the differences are driven by how nutrient-rich the region of ocean above the trenches is.

“If you look at the New Hebrides trench, and where it is geographically, it lies under very unproductive waters – there is not a lot happening at the surface of the tropical waters,” said Dr Jamieson.

“It seems the cusk eels are specialists in very low food environments, whereas the grenadiers require a greater source of food.”

This expedition forms part of a new wave of exploration of the deep ocean.

Trench 4Almost all of this has been carried out using landers or underwater robots, but in 2012, Hollywood movie director James Cameron made a record-breaking dive to the deepest place in the ocean – the Mariana trench.

He described it as an alien place, devoid of life. This may be because it lies so far from the continental shelf, which means very few nutrients drift down into the trench, which is nearly 11km deep, making food extremely scarce.

But while larger creatures may be absent, scientists recently revealed that microscopic life is plentiful at the bottom of the Mariana trench.

 

Source: www.bbc.co.uk/news

Marine Life & Conservation

Komodo National Park found to be Manta Hotspot

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Through a collaborative effort between citizen divers, scientists from the Marine Megafauna Foundation (MMF), and Murdoch University, a new study reports a large number of manta rays in the waters of Komodo National Park, Indonesian, a UNESCO World Heritage Site, suggesting the area may hold the key to regional recovery of the threatened species.

Reef mantas (Mobula alfredi), which grow up to 5m, tend to reside and feed in shallow, coastal habitats. They also visit ‘cleaning stations’ on coral reefs to have parasites, or dead skin picked off by small fish. Courtship ‘trains’ are also observed adjacent to cleaning stations. In Komodo National Park, manta rays are present year-round, challenging the famous Komodo dragon as the most sought-after megafauna for visitors.

Scientists teamed up with the dive operator community to source identification photographs of manta rays visiting the parks’ waters and submit them to MantaMatcher.org – a crowdsourced online database for mantas and other rays. Most of the photographs came from just four locations from over 20 commonly visited by tourism boats.

I was amazed by how receptive the local dive community was in helping collect much-needed data on these threatened animals,” said lead author Dr. Elitza Germanov. “With their support, we were able to identify over 1,000 individual manta rays from over 4,000 photographs.

People love manta rays—they are one of the most iconic animals in our oceans. The rise of the number of people engaging in SCUBA diving, snorkeling, and the advent of affordable underwater cameras meant that photos and videos taken by the public during their holidays could be used to quickly and affordably scale data collection,” said MMF co-founder and study co-author Dr. Andrea Marshall.

The photographs’ accompanying time and location data is used to construct sighting histories of individual manta rays, which can then be analyzed with statistical movement models. These models predict the likelihood that manta rays are inhabiting or traveling in between specific sites. The study’s results showed that some manta rays moved around the park and others as far as the Nusa Penida MPA (>450 km to the west), but overall, manta rays showed individual preferences for specific sites within the Park.

I found it very interesting how some manta rays appear to prefer spending their time in some sites more than others, even when sites are 5 km apart, which are short distances for manta rays,” said Dr. Elitza Germanov. “This means that manta rays which prefer sites where fishing activities continue to occur or that are more popular with tourism will endure greater impacts.”

Fishing activities have been prohibited in many coastal areas within Komodo NP since 1984, offering some protection to manta rays prior to the 2014 nationwide protection. However, due to illegal fishing activity and manta ray movements into heavily fished waters, manta rays continue to face a number of threats from fisheries. About 5% of Komodo’s manta rays have permanent injuries that are likely the result of encounters with fishing gear.

The popularity of tourism to these sites grew by 34% during the course of the study. An increase in human activity can negatively impact manta rays and their habitats. In 2019, the Komodo National Park Authority introduced limits on the number of boats and people that visit one of the most famous manta sites.

This study shows that the places where tourists commonly observe manta rays are important for the animals to feed, clean, and mate. This means that the Komodo National Park should create measures to limit the disturbance at these sites,” said Mr. Ande Kefi, an employee of the Komodo National Park involved with this study. “I hope that this study will encourage tourism operators to understand the need for the regulations already imposed and increase compliance.”

Despite Indonesia’s history with intensive manta ray fisheries, Komodo National Park still retains large manta ray aggregations that with careful ongoing management and threat reduction will benefit regional manta ray populations. The study highlights that marine protected areas that are large enough to host important manta ray habitats are a beneficial tool for manta ray conservation.

For more information about MMF visit their website here.

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Euro-Divers opens to guests at Alila Kothaifaru Maldives

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In celebration of Euro-Divers’ 50 Years of Diving with Friends in the Maldives, the team have opened a new PADI 5 Star Dive Center at Alila Kothaifaru Maldives.

Alila Kothaifaru Maldives retreat lies at the northern edge of the Maldives in the tranquil Raa Atoll, reached via a panoramic 45-minute seaplane voyage from Male. The island has 80 all-pool-villas, 36 of which are over water with a private pool for your enjoyment and 44 beachfront villas designed seamlessly to immerse guests in the natural surroundings. In support of sustainable tourism, Alila hotels adopt Earth Check operating standards, integrating their environments’ natural, physical, and cultural elements.

Raa Atoll is well-known for the excellent scuba diving it offers. The underwater landscape of Raa Atoll is characterized by a high number of thilas scattered inside the lagoons. These underwater coral mountains are magnets for marine life including huge schools of tropical reef fish, a generous splash of colour, iconic bucket-list-must-see marine creatures including sharks, mantas (appearing during the entire year), turtles, and uncrowded dive sites—a perfect diver’s heaven for beginners and experienced divers. We offer a full range of PADI courses for different levels. From November till March, the Manta cleaning station is located 15 minutes away by boat.

The team from Alila Kothaifaru Maldives look forward to welcoming you soon.

Find out more at: www.euro-divers.com/alila-kothaifaru-maldives

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A luxurious dive resort in the heart of Lembeh Strait. Enjoy refined services while exploring the rich waters of Indonesia.

The resort is nestled around an ocean front deck and swimming-pool (with pool-bar) which is the perfect place to enjoy a sundowner cocktail at the end of a busy day of critter-diving.

All accommodation is full board and includes three sumptuous meals a day. Breakfast and lunch are buffet meals and in the evening dining is a la carte.

Book and stay before the end of June and benefit from no single supplements in all room types!

Booking deadline: Subject to availability – book and stay before end of June 2022

Call Diverse Travel on 01473 852002 or email info@diversetravel.co.uk.

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