Connect with us
background

News

Fish On Acid Lose Fear Of Predators

Published

on

Coral reef fishes exposed to acid oceans lose their sense of smell – and their sense of caution – and are more likely to fall prey to natural enemies, according to new research in Nature Climate Change.

The finding is based on observations of the behaviour of four species at a reef off the coasts of Papua New Guinea where natural carbon dioxide seeps out of the rock, and confirms a series of other such studies in the last year.

A cool volcanic discharge in the reef has served as a natural laboratory for years: water in the region reaches an average pH of 7.8. This standard measure of acidity is co-incidentally the level predicted for all the world’s oceans by 2100, as atmospheric carbon dioxide levels continue to rise, according to the Intergovernmental Panel on Climate Change.

Australian and US scientists observed the fishy behaviour from a boat moored above the reef, and also tested the fish on board the vessel. What they observed was that, away from the volcanic bubbles of carbon dioxide, in conditions of more normal ocean chemistry, damsel fish and cardinal fish seemed able to smell predators and stayed in sheltered places in the reef to avoid becoming prey.

Fish from the waters richer in carbonic acid seemed not to sense the presence of predators, and were more likely to venture into dangerous waters.

After a sudden scare that sent all the fish racing for cover, the fish from the bubble reef ventured forth much sooner. In normal circumstances, such fish spend 80% of their time under cover.

The bubble reef fish spent at most only 12% of their time in hiding. Mortality accordingly was five times higher.
“Their sense of smell was acutely affected in CO2-rich waters in ways that gravely threaten their survival,” said Alistair Cheal of the Australian Institute of Marine Science.

“We were able to test long-term realistic effects in this environment,” said another author, Danielle Dixson of the Georgia Institute of Technology in the US. “One problem with ocean acidification research is that it’s all laboratory-based, or you’re testing something that’s going to happen in 100 years’ time with fish that are from the present day, which is not actually accurate.”

The reasoning is that the change in pH levels disrupts a neuroreceptor in the fishes’ brains and affects faculties or alters behaviour. Similar experiments with Californian rockfish have demonstrated much the same effect.

But increased acidification of the oceans is also likely to affect shellfish and corals in other ways, and research in the Great Barrier Reef region of Australia has documented a dramatic behaviour change in a jumping snail that suggested impaired decision-making capability as pH levels alter.

Sea water is already 30% more acidic that it was at the start of the Industrial Revolution 200 years ago. The rate of change is at least 100 times faster than at any time in the last 650,000 years.

The bubbling waters of the reef under test are not unique – such localized carbonic acid seeps occur in many places all over the world – and the fact that predators might find easy pickings in such places makes no real difference to population levels in the vastness of the rest of the ocean. But such experiments raise the question: can ecosystems adapt to changing water chemistry?

“Continuous exposure does not reduce the effect of high CO2 on behaviour in natural reef habitat and this could be a serious problem for fish communities in the future when ocean acidification becomes widespread as a result of continued uptake of anthropogenic CO2 emissions,” the authors conclude.

 

Source: www.truthdig.com

News

Euro-Divers opens to guests at Alila Kothaifaru Maldives

Published

on

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

Continue Reading

Marine Life & Conservation

Blue Marine Foundation launches new partnership with Dutch Caribbean Nature Alliance

Published

on

Ocean charity makes initial grant of $90,000 to marine parks on six Dutch Caribbean islands. Award will fund projects including coral protection, and training youth marine rangers.

Ocean conservation charity Blue Marine Foundation has announced it is awarding $90,000 in funding to support marine conservation in the Dutch Caribbean. A range of projects run by protected area management organisations on six islands will each receive a grant of $15,000. The funding is the first step in a longer-term partnership to support the islands and help secure sustainable financing through the Dutch Caribbean Nature Alliance (DCNA) Trust fund.

To improve ocean governance, Blue Marine uses a combination of top-down intervention and bottom-up project delivery to help local communities at the front line of conservation. It will work together with the DCNA to help marine-park organisations protect the unique and threatened biodiversity of the Dutch Caribbean.

The new partnership is an important development in the successful management of marine conservation parks in the Dutch Caribbean. The UK-based charity has established a small-grants fund to provide rapid access to support for critical conservation projects run by marine parks.

The individual projects and their local partners are:

Unique ecosystems on the islands are vulnerable to threats such as feral livestock causing sedimentation on reefs, and invasive species, including lionfish and coral diseases. They are also at risk from overfishing, climate change, coastal development, erosion and the build-up of harmful algae caused by waste water.

The islands of the Dutch Caribbean are also home to important “blue carbon” habitats – ocean ecosystems such as seagrasses, mangroves and other marine plants that suck up and lock away carbon from the earth’s atmosphere. Seagrass is so efficient at this it can capture and store carbon dioxide up to 35 times faster than tropical rainforests.  The management and protection of these blue carbon habitats is vital in the fight against climate change.

Current marine conservation measures in the islands include a 25,390 square km mammal and shark sanctuary- Yarari sanctuary- across the Exclusive Economic Zone of Bonaire, Saba and St Eustatius. All six islands have inshore Marine Protected Areas ranging in size from 10 to 60 sq km.

Blue Marine’s Senior Project Manager Jude Brown commented: “Having recently visited two of the islands, I witnessed first-hand how special this region is. Diving the waters off Saba I saw huge Tarpon swimming amongst shoals of blue tang, and hawksbill turtles feeding on the seagrass beds. I also witnessed the challenges these islands are facing from coral disease to issues with coastal development. It is an exciting opportunity to work in the Dutch Caribbean, bringing expertise and funding from Blue Marine to join with the wealth of knowledge already on the islands, to work together to protect the important marine life arounds these islands.”

Tadzio Bervoets, Director of the DNCA commented: “The Dutch Caribbean consists of the Windward Islands of St. Maarten, Saba, and St. Eustatius and the Leeward Islands of Aruba, Bonaire and Curaçao. The nature of the Dutch Caribbean contains the richest biodiversity in the Kingdom of the Netherlands. The diverse ecosystems are a magnet for tourism and at the same time the most important source of income for residents of the Dutch Caribbean. Nature on the islands is unique and important but it is also fragile. The coming week we will be in The Netherlands to present a Climate Action Plan for the Dutch Caribbean to emphasize the urgent need for a climate smart future for our islands.”


Photo: Coral reefs in the Dutch Caribbean- Photo credit: Naturepics: Y.+T. Kühnast- all rights reserved

Continue Reading

E-Newsletter Sign up!

Competitions

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.

More Less

Instagram Feed

Popular