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Madagascar emerges as hotspot for endangered whale sharks

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A new study published in the journal Endangered Species Research has revealed that juvenile whale sharks swim to Madagascar, a newly-identified hotspot for these huge fish, to feed. Eighty-five individual sharks were identified in a single season using photographs of their distinctive spot patterns. An isolated ‘island continent’, famed for animals and plants that exist nowhere else in the world, Madagascar’s nutrient-rich waters are also home to an incredible array of marine life attracting increasing numbers of tourists.

Whale shark and fishes – Copyright Simon J Pierce, www.simonjpierce.com

Whale sharks are primarily seen around the small island of Nosy Be, in northwest Madagascar. This area is a globally important hotspot for large marine species, including manta rays, sea turtles, humpback whales and even rare Omura’s whales. The study is part of the Madagascar Whale Shark Project, a collaboration initiated in 2016 by researchers from the Marine Megafauna Foundation, Florida International University, and Mada Megafauna.

Lead author and project leader Stella Diamant said: “We’ve found that whale sharks regularly visit Nosy Be between September and December. That has led to a growing ecotourism industry, as people travel to see and swim with these gigantic, harmless sharks. We’re still learning about their population structure and movement patterns, but it’s clear the area is an important hotspot for the species.”

Whale sharks are the largest fish in the world, growing up to 20 meters long. However, all of the sharks seen in Madagascar have been juveniles of less than nine meters.

We identified 85 individual whale sharks over our first season in 2016. Some of the sharks were present across several months. They spend a lot of time in the area and seem to come here to feed,” Diamant said.

Stella Diamant on boat – Copyright The Madagascar Whale Shark Project

The marine biologists uploaded photographs of the sharks’ unique spot patterns to Wildbook for Whale Sharks (a global database of sightings) and compared them with data collected from known feeding areas in the Indian Ocean, including Djibouti, the Maldives, Mozambique, Seychelles and Tanzania, but found no overlap.

Whale sharks are a globally endangered species due to overfishing, accidental catches and boat strikes. Major declines in sightings have been seen in Mozambique, where we’ve documented a 79% decline in sightings since 2005, and the Seychelles. I was hoping that some of those sharks might have shifted over to Madagascar”, said co-author Dr Simon Pierce, co-founder and principal scientist at the Marine Megafauna Foundation.

Unfortunately, that doesn’t seem to be the case. It’s great news for Madagascar though. These sharks can be a major asset for the country. There’s already a good marine ecotourism industry developing”, he added.

As part of this study, the team attached eight satellite tags to immature whale sharks to track their movements in near real-time. They found that the sharks spent most of their time in shallow waters between 27.5-30°C around the tagging area in Nosy Be.

Stella Diamant with tagged shark – Copyright Simon J Pierce, www.simonjpierce.com

Half of the tagged sharks also visited a second hotspot near Pointe d’Analalava, 180 km south of Nosy Be. Five of the sharks swam over to Mayotte and the Comoros islands, and two swam right down to the southern end of Madagascar. One of those sharks then swam back to Nosy Be, a total track of 4,275 km. The sharks are slow-swimmers, travelling an average 21 km per day. Three sharks were resighted in the Nosy Be area the following season after having lost their tags.

It was exciting to see that there is a second hotspot for the sharks in the area. We will be exploring the area later this year. Madagascar clearly provides an important seasonal habitat for these young whale sharks, so we need to ensure they are effectively protected in the country”, concluded Diamant.

Madagascar is a known location for shark fishing and finning. Whale sharks are currently afforded no formal protection except in two Marine Protected Areas located to the southwest and northeast of Nosy Be.

Over the last decade, shark populations have declined dramatically in Madagascar due to overfishing. However, the most significant threat to this species is the incidental catch in coastal gillnets and industrial purse seiners operating offshore”, said Dr Jeremy J Kiszka, a marine biologist at Florida International University and co-scientific lead of the Madagascar Whale Shark Project.

Whale sharks are listed as ‘endangered’ on the IUCN Red List of Threatened Species since 2016 and received an Appendix I listing the UN Convention on Migratory Species in 2017. As a signatory to the Convention, Madagascar is obligated to protect the sharks and their migratory habitat in national waters.

The study was supported by Les Baleines Rand’eau, Aqua-Firma, PADI Foundation, IDEA WILD, Waterlust, the Shark Foundation, and two private trusts.

Stella Diamant, Christoph A Rohner, Jeremy J Kiszka, et al. ‘Movements and habitat use of satellite-tagged whale sharks off western Madagascar’ was published on 17 May 2018 and is available here.


For more information about Marine Megafauna Foundation please visit:

Website: www.marinemegafauna.org
Facebook: www.facebook.com/MarineMegafauna

Images by www.simonjpierce.com

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Historical Submarine Prototype protected

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The wreck of an early British submarine known as HMS/m D1, which was the forerunner to the Royal Navy’s patrol submarines that boosted Britain’s defensive power during the First World War, has been granted protection by the Department for Digital, Culture, Media and Sport on the advice of Historic England.

The wreck, off the coast of Dartmouth in Devon, was investigated in a project originated by U-boat historian Michael Lowrey, who was writing a book about First World War U boat losses. The wreck was identified by a team of technical divers who are skilled at diving at depths of over 40 metres, led by Steve Mortimer, diving from Wey Chieftain IV. They reported the discovery of HMS/m D1 to Historic England and it has now been protected by scheduling. This means divers can dive the wreck but its contents are protected by law and must remain in situ.

Multi-beam image of the newly- protected prototype of the D-Class submarine which was deliberately sunk off the coast of Dartmouth, Devon in 1918 and used as a target to test submarine detection equipment. Copyright Wessex Archaeology

HMS/m D1 was built by shipbuilding company Vickers at Barrow-in-Furness in Cumbria and was the secret prototype for the D-class, the Royal Navy’s first diesel powered submarine. Launched in 1908 and commissioned in September 1909, the D-class was a significant development on the C-class submarine, being larger and more powerful.

At the start of the First World War, HMS/m D1 was assigned to protecting the coast of Dover from enemy invasion before carrying out patrols outside of English territorial waters to monitor German shipping movements. In September 1917, HMS/m D1 joined the Portsmouth Local Defence Flotilla and a year later it was relegated to training duties. In October 1918, HMS/m D1 was decommissioned and scuttled- deliberately sunk. The submarine was used as a training target off the Devon coast for Royal Navy training exercises involving the detection of enemy submarines. The wreck sits upright and largely intact on the seabed.

Multi-beam image of the newly- protected prototype of the D-Class submarine. Copyright Wessex Archaeology

Duncan Wilson, Chief Executive of Historic England said: “The D-class submarine was superior to the C-class, with innovations that became integral parts of future Royal Navy submarines. These included diesel propulsion, twin propellers and a wireless telegraphy system which allowed the submarine to transmit and receive signals. This is a fascinating survival which deserves protection as an important part of our seafaring history.”

Lead Diver Steve Mortimer said: “Every diver dreams of identifying a historically important wreck.  Expecting to find the remains of a German U-boat, we were thrilled to discover a ground-breaking British submarine instead.  It’s tremendous that D1 is now protected but divers can still visit.”

Eight D-class submarines were built. HMS/m D2, HMS/m D3 and HMS/m D6 were sunk outside English territorial waters, while HMS/m D4, HMS/m D7 and HMS/m D8 were sold and scrapped in 1919. The wreck of HMS/m D5 is located off Lowestoft. Suffolk, and is protected under the Protection of Military Remains Act 1986.

For more information, please visit www.historicengland.org.uk

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Tried & Tested: INON UWL 95- C24 Wide Angle Wet Lens

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The INON UWL 95- C24 is the latest wide angle wet lens released by INON and has been designed for compact cameras with zoom lenses that are 24mm at the wide end. The UWL-95 C24 has a maximum angle of view of 95° underwater. This can be increased up to 141° with the optional Dome Lens.

The lens has a versatile M67 screw mount and M52 screw mount, the M52 fitting is already built in. Because the M67 rings are screwed to the lens over this, they can’t come loose like a step up rings. Totally renewed optical design effectively suppresses flare/ghost even in backlit condition to provide sharp and high quality image.

Test Conditions

  • Location: Capernwray Quarry, UK
  • Visibility: 2-3m
  • Temperature: 9 degrees C
  • No of Dives: 1
  • Equipment Used: Canon S110 in Recsea housing
  • Test Equipment: INON UWL 95- C24 with Dome Lens Unit 111A and 67mm thread.
  • RRP of lens and accessories used: £667.98

Review

This was an eagerly awaited new product from INON – a wide angle wet lens that can be used with hugely popular compact cameras such as the Olympus Tough and the Sony RX100 range. Testing new equipment in less than ideal conditions is always a challenge, but it is also a bonus, as for many, these will be the conditions they will experience too. Testing a new lens on an unfamiliar camera system also makes this process harder, as you need time to adjust to the new system, even though that is not what you are testing. My first impressions of this lens, before getting it underwater, was that it is very well made.

As we descended I started to unscrew the lens to ensure that any air trapped between camera housing and lens was released. As long as you do not undo all the way this works perfectly, however with thick gloves, in cold water, I would not want to have to attach the lens onto the camera using the 67mm thread very often as it feels a little fiddly.

Using the UWL-95 C24 can dramatically reduce minimum focusing distance needed between photographer and subject. As the visibility on the testing day was only 2-3m this was very good news indeed and the lens focused on subjects that were virtually touching the lens. Be careful not to get too close to anything that might scratch the lens! The lens, with the additional dome gave a really wide field of view, perfect for wreck, diver, scenic and large marine life shots.

Whilst the lens feels quite heavy on the front of a small camera out of the water, I did not notice it at all on the dive which is great, as some big lenses can require floats or very strong wrists to make them workable. This is a simple grab and go lens that does not need any additional kit or know-how to use. Alas, due to my buddy having a catastrophic dry suit flood, I only got a single dive to try it out, but was impressed with it nonetheless.

Fortunately I am taking the lens up to Scotland to try out on my Olympus TG5 whilst snorkeling and wild swimming – so watch out for more about this lens next month.

For more information visit the INON website by clicking here.

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