Manta rays and whale sharks consuming massive amounts of plastics near Indonesia

NOVEMBER 20, 2019 REPORT

by Bob Yirka , Phys.org 

Various sizes and types of plastic debris found in manta ray vomit material (n = 1) from Nusa Penida, Indonesia. Larger debris are photographed under high (A,B) and low (C) magnification, and smaller debris (D) under high magnification. Credit: Frontiers in Marine Science (2019). DOI: 10.3389/fmars.2019.00679 

A team of researchers from Australia, the U.S., Indonesia and New Zealand has measured the amount of plastics that manta rays and whale sharks are ingesting off the coast of Indonesia. In their paper published in the journal Frontiers in Marine Science, the group describes how they measured the ingestion of plastics by the marine animals. 

There is a large amount of plastic in the ocean due to a variety of human activities. In recent years, scientists have been trying to better understand the impacts of the plastic on marine life. In this new effort, the researchers focused on manta rays and whale sharks, and plastics in the ocean off the coast of parts of Indonesia. 

The work began after one of the team members went swimming off the coast of Indonesia and found the waters teeming with plastics. Curious about the impact of so much plastic on marine creatures that sift plankton for their survival, they undertook a study to learn more. 

The work involved tossing fine-meshed nets over the side of a boat and trolling to mimic the way mantas and whale sharks feed—they noted the mesh was fine enough to collect both plankton and very tiny bits of plastic. They noted also that they trolled areas that were known to be feeding grounds for both marine animals.

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Novel approach studies whale shark ages the best way -- while they are swimming

New study reveals world's largest fish is larger and lives longer than previously thought

Date:  July 18, 2018

Source:  Nova Southeastern University

Summary:

A new study of whale sharks, using a novel approach to gathering data, shows these endangered animals can live longer and grow larger than previously believed.

Already the world's largest shark species, male whale sharks can swim around the ocean for up to 130 years, according to a recently published study by scientists at Nova Southeastern University's (NSU) Guy Harvey Research Institute (GHRI) and collaborators from the Maldives Whale Shark Research Programme.

The research on whale shark aging growth dynamics, published in the Marine and Freshwater Research Journal, was conducted in the Republic of Maldives using a unique approach.

According to Cameron Perry, the first author of the scientific paper, and at the time a graduate student at NSU's GHRI, "What makes this a novel approach is that we took repeated noninvasive underwater measurements of live sharks over the course of a decade.

"Up to now, such aging and growth research has required obtaining vertebrae from dead whale sharks and counting growth rings, analogous to counting tree rings, to determine age. Our work shows that we can obtain age and growth information without relying on dead sharks captured in fisheries. That is a big deal."

According to the research study, "Comparing length-measurement methods and estimating growth parameters of free-swimming whale sharks (Rhincodon typus) near the South Ari Atoll, Maldives," taking repeated measurement of the same sharks over many years was possible because many of these sharks came back to the same place every one to two years, and individuals could be recognized by their unique spot patterns. The researchers then modeled their measurement results and found that:

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Madagascar emerges as whale shark hotspot

By Helen BriggsBBC News

17 May 2018

Large numbers of endangered whale sharks have been sighted in waters off Madagascar.

The first major scientific survey in the area shows there are far more of the huge fish than previously thought.

Eighty-five individuals were identified in a single season from photographs of their distinctive markings.

The coastal waters contain a huge diversity of marine life, including sharks, whales and turtles.

"No one thought there were that many [whale] sharks," said Stella Diamant of the Madagascar Whale Shark Project in Nosy Be, an island off the coast of Madagascar.

"They don't seem to be there all year round - they come back for the food."

Many stars

Whale sharks, which have unique spot patterns, are known locally as marokintana, meaning many stars.

The marine biologists uploaded photographs of the sharks' markings to a global database of sightings known as the Wildbook for Whale Shark.

They found no overlap with data collected from other feeding areas in the Indian Ocean, suggesting the whale sharks - all juveniles - had not migrated from Mozambique or other neighbouring areas.

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2 Whale Shark Sightings in Maryland: Are These Colossal Fish Dangerous?

By Tia Ghose, Senior Writer | July 12, 2017 06:17am ET

The world's largest fish, a whale shark, recently got up close and personal with fishers in Ocean City, Maryland, nudging their boat for long enough that the crew captured a stunning video.

Steve Moore — who helms the boat, dubbed "The Stalker" — was on an overnight fishing trip in late June when the crew spotted the 30- to 35-foot-long (9 to 11 meters) whale shark, the Delmarva Daily Times reported. A second sighting, on July 4, occurred near the same spot. At that point, fisherman Josh Schleupner jumped into the water to snorkel with the majestic fish, capturing awe-inspiring video in the process, the Delmarva Daily Times reported. [On the Brink: A Gallery of Wild Sharks]

But although the video of a monster fish nudging its snout into a boat or swimming just feet from a human may seem scary, such occurrences are usually not dangerous, nor are they particularly rare, said Alistair Dove, vice president of research and conservation at the Georgia Aquarium.

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Indonesia must do more to protect whale sharks, conservationists say

23 August 2016 / Fidelis E. Satriastanti

The world’s largest fish was recently declared an endangered species.

Most whale sharks live in the Indo-Pacific, where Indonesia lies.

The giant fish is a protected species in Indonesia, but that hasn't stopped poachers from hunting it for its fins, skin and oil.

Advocates want the Indonesian government to crack down on traffickers and do more to promote sustainable ecotourism that contributes to the creature's conservation.

In 2013, Indonesia declared the whale shark a protected species, hoping to put a dent in the thriving trade in its body and parts which was pushing the world’s largest fish toward extinction.

The new distinction failed to halt an alarming decline in its numbers. Earlier this year, the whale shark (Rhincodon typus) was uplisted from Vulnerable to Endangered on the IUCN Red List.

Now, conservationists are saying Indonesia must do more to protect the school bus-sized creature, including through improved ecotourism management, law enforcement and legal protection.

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Whale and winghead sharks move step closer to extinction

Two predatory species are added to IUCN Red List of endangered species as pressure from fishing sees their populations fall by half in the last 75 years

Arthur Neslen

Friday 8 July 201615.58 BSTLast modified on Monday 11 July 201609.33 BST

Whale sharks and winghead sharks have moved one step closer to extinction, after the International Union for the Conservation of Nature (IUCN) redefined them both as endangered species on the group’s “red list”.

The two predatory species have fallen foul of increased pressure from human activity, especially the fishing industry, with populations of whale sharks – the world’s largest living fish – halving in the last 75 years.

Jane Smart, the director of the IUCN’s Global Species programme said: “It is alarming to see such emblematic species slide towards extinction. The world’s oceans and forests will only continue to provide us with food and other benefits if we preserve their capacity to do so.”

Whale sharks continue to be killed by ship propellers and fishing fleets, particularly in China and Oman. Whale sharks are often present in tuna shoals, and are frequently landed by fishermen as incidental catch.

“While international whale shark trade is regulated through the species’ listing on the Convention on the International Trade in Endangered Species (Cites), more needs to be done domestically to protect whale sharks at a national level,” said Simon Pierce, the IUCN’s lead red list assessor.

continued ...

Biggest fish in the ocean receives international protection

Date:

January 20, 2015

Source:

NOAA Fisheries West Coast Region

Summary:

Tuna and other fish species may congregate around whale sharks, but new rule reduces the chance that the giant sea creatures could get caught in nets targeting those species.

Continued ...

Giant Squid and Whale Sharks Aren't As Big As People Think

When it comes to determining the size of giant squid and other large sea animals, humans have a tendency to exaggerate, a new study suggests.

A team of researchers compared scientific and popular media reports of body sizes for 25 species of marine creatures, including whales, sharks, squids, and other giant ocean dwellers, and found that most of the animals were smaller than what was reported.

"It's human nature to tell a "fishing story,'" said Craig McClain, a marine biologist at the National Evolutionary Synthesis Center in Durham, North Carolina. In reality, "we're horrible at saying what the size of something is, without actually taking a measurement."

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Whale sharks to be tagged to save species

Technology will uncover the mating secrets of these enigmatic giants

LEWIS SMITH 

Sunday 28 December 2014

It is the largest fish in the ocean with some individuals reaching sizes of up to 65ft (18m) long and weighing more than 30 tonnes, but whale sharks remain one of the enigmas of the deep.

There are fears that the gentle giant, whose flesh is prized in countries such as China, India and the Philippines, is being slowly driven towards extinction. And so little is known about them that there is huge uncertainty about how their decline can be arrested.

Scientists and conservationists hope to safeguard the giant creatures' future by electronically tagging them to uncover their secrets. The project is being supported by the Galapagos Conservation Trust, based in London. Spokesman Peter Haskell said: "We are starting to build a picture of the whale shark's global migration."

Divers from the Galapagos Whale Shark Trust plan to tag both males and females off the coast of Peru to trace where they go and what they do. One of their main hopes is that it will reveal where in the ocean the species courts and mates, a key piece of information in the fight to understand and protect it.

"We don't know where they mate, we don't know where they give birth and we don't know where they spend the first couple of years of their lives," said Dr Alex Hearn of the Galapagos Whale Shark Trust.

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The Maldives and the whale shark: World's biggest fish adds value to paradise

Date:

August 12, 2014

Source:

PeerJ

Summary:

They are the largest fish in the world but the impact of this majestic and charismatic animal on the economy of the island nation of the Maldives was largely unknown. A new study reveals that a small group of whale sharks in a single Maldivian Atoll accounts for nearly 3 percent of the global shark ecotourism and nearly half that of the Maldives'.

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600 threatened whale sharks killed each year at Chinese slaughterhouse

Hong Kong environmental group Wildlife At Risk has just released a report on a whale shark slaughterhouse in China’s southeastern Zhejiang Province. A 4 year investigation has revealed that 600 whale sharks are killed there each year. The whale shark is listed as vulnerable on the IUCN Red List.

The factory is located at Pu Qi township, near Wenzhou and at least 600 whale sharks are killed each year to be processed into fish oil health supplements.

In a joint-statement released today, Alex Hofford and Paul Hilton of WildLifeRisk said: “We went to Pu Qi three times in the last three years, and on each occasion the scale of the slaughter was truly staggering.

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Kenya rejects proposal to capture and exploit whale sharks

Kenya's whale sharks - Born free and staying free!

September 2013. Plans to create an artificial marine enclosure off the southern coast of Kenya and stock it with wild-caught specimens of the world's largest fish - the whale shark - as a tourism attraction have been comprehensively rejected by the government of Kenya.

The judgement delivered by the National Environmental Management Authority of Kenya cited in their determination that the proposed project:

Denied whale sharks their right to exist in their natural habitat 

Did not adequately engage with local communities 

Did not recognise that whale shark tourism can be promoted in the wild without capturing these animals 

Would have been in contravention of Kenya's 1962 Animal Cruelty Act

The Born Free Foundation and others presented their concerns at a Public Hearing held in Kenya in February 2013 and called for the proposal by Volker Bassen of Seaquarium Ltd to be rejected. Their sentiments were echoed by many people who wrote from all over the world to key Kenyan decision-makers expressing their dismay.

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Whale shark capture threatens Kenya’s image for responsible tourism

Whale sharks are the largest fish, reaching lengths of more than 12 metres and weights of more than 20 tonnes, abd are highly migratory - Totally unsuitable for captivity. Credit EAD

Ill-advised tourism ‘adventure' threatens Kenyan Whale sharks - Born Free Foundation and international marine experts are outraged

March 2013. Plans to capture and keep some Whale sharks in an enclosure off the south coast ok Kenya threatens Kenya's hard fought for reputation as a responsible tourism destination. Under the sham pretence of conservation, the company involved is hoping to make money from visits and people paying to swim with whale sharks.

Whale sharks are migratory and deep diving filter feeders, three things that captive animals will be unable to do. This thinly veiled attempt to make money from captive whale sharks will put people off visiting Kenya altogether. Kenya has spent many years building up its image as a leader in Responsible Tourism, and has led the fight against elephant poaching and legalising ivory sales, but this gross idea threatens to undermine many years of hard work.

A huge outcry has been sparked off amongst conservation groups and marine scientists by plans by Seaquarium Ltd. in Kenya to begin catching wild migrating whale sharks for public display in a marine enclosure off the southern Kenyan coast, ostensibly for the purposes of "tourism and conservation."

Fully Protected

Whale sharks are the largest fish on the planet and, while their huge size and gaping-mouthed appearance can be terrifying, these docile plankton feeders pose no threat to man and are fully protected under various international wildlife laws and conventions.

Continued:  http://www.wildlifeextra.com/go/news/kenya-whale-shark.html

Controversy over feeding of world's largest shark

Tan-awan, in the southern Philippines island of Cebu, used to be a sleepy village that never saw tourists unless they were lost or in transit. Yet now they flock there by the hundreds - to swim with whale sharks, the world's largest fish.

Whale sharks are lured to the Tan-awan coastline of the Oslob district by fishermen who hand feed them small shrimp, drawing divers and snorkelers to see the highly sought-after animals, known as gentle giants of the sea.

But the practice has sparked fierce debate on the internet and among biologists, who decry it as unnatural.

Read more: http://www.canberratimes.com.au/travel/travel-news/controversy-over-feeding-of-worlds-largest-shark-20130313-2fzp3.html#ixzz2O04OzTt4

Scientists Using Holiday Snaps to Identify Whale Sharks

Feb. 8, 2013 — Holidaymakers' photos could help scientists track the movements of giant endangered sharks living in the waters of the Indian Ocean. A new study, led by a researcher from Imperial College London, is the first to show that these publically sourced photographs are suitable for use in conservation work.

Tourists scuba diving and snorkelling in the Maldives frequently take underwater pictures of the spectacular and docile whale shark, often called the world's largest fish. Conservationists have long hoped to use this photographic resource to help them trace the sharks' life history, relationships and geographic distribution, although the value of these amateur snapshots has never been properly measured.

Tim Davies of Imperial's Department of Life Sciences is the lead author on a study published in Wildlife Research, the first to examine how reliable photographs sourced from the public actually are. He and his team did this by comparing results using tourist images with results based on surveys by marine researchers specifically aiming to track the sharks.

In order for a shark to be clearly identified, any photograph must capture the distinctive pattern of spots located directly behind the gills. This unique marking serves as a 'fingerprint', which can then be scanned with a computer programme to tell the animals apart.

Continued:  http://www.sciencedaily.com/releases/2013/02/130208124629.htm

Donsol, the town built on Whale sharks

Another example of the good that tourism can do for wildlife, conservation and communities

November 2012. What a big difference conservation makes. Barely 15 years ago, the Philippines coastal town of Donsol was a 5th class rural municipality - where weathered vehicles spurred swirling clouds on dusty, unpaved roads. Sitting 540 kilometres southeast of Manila, the Donsol of the early 1990s was a relaxed and reticent town of fisherfolk and farmers.

1998 - Amateur video of Whale sharks

Donsol finally embraced destiny in 1998 - when an amateur home-video brought to Manila by diver David Duran revealed Whale sharks (Rhincodon typus) - Earth's largest fish species - swimming and feeding right in the Bay. Back then, the world's most popular Whale shark tour was still in Ningaloo Reef, off the western coast of Australia. Aside from being rather pricey ($350 to $500) per head), interactions were not guaranteed.

Though occasionally gathering in other spots such as Australia, Mexico and parts of Africa, Donsol's Whale sharks mostly keep within a kilometre from shore, perfect for gutsy tourists bearing snorkels and masks. With strong government leadership and the support of the World Wide Fund for Nature (WWF), the townsfolk of Donsol took the plunge - and entered the history books.

Photo ID
Since 1998, WWF-Philippines has been spearheading a holistic conservation program which ranges from satellite tagging and photo-identification to the effective management of tourism impacts. Current efforts are supported by WWF-Denmark, ECOCEAN, the Hubbs Sea World Research Institute (HSWRI), CERTINA and Banco de Oro Unibank (BDO) and include vigorous environmental education drives to transform public school children into ecological champions.

25000 visitors per year
Today Donsol receives an average of 25,000 visitors each summer - a sharp contrast to the 867 recorded in 2002. Sailing on the influx of tourists, boat trips rose from barely 340 in 2002 to over 5300 per season. For the Philippines, Donsol has indeed become whale shark central.

Read on:  http://www.wildlifeextra.com/go/news/donsol-whaleshark-visit.html

Indonesia's 'unique' whale sharks get pet tags

The "unique habit" of whale sharks that converge to feed fromfishing nets in Indonesia has allowed them to be tagged with low-cost technology usually used on pets, conservationists said Tuesday.

Experts in June injected tiny pill-sized radio transmitters beneath the skin of 30 whale sharks in Cenderawasih Bay in the eastern province of Papua, conservation group WWF said.

And it was only made possible because the giant animals, which measure up to 45 feet (13.7 metres) but are harmless to humans, were gathered to feed on fish caught in fishermen's nets, WWF Indonesia project leader Beny Ahadian Noor told AFP.

A YouTube video by Conservation International (CI) showing a whale shark sucking fish from a hole in a net in clear blue waters has now attracted more than one million views (www.youtube.com/watch?v=71FLO_6JJVo).

"Radio-frequency identification (RFID) tags have been used on pets such as dogs, but this is the first time on whale sharks," Noor said.

Researchers would usually use a more sophisticated satellite method, at $4,000 a tag. But Noor said each radio-frequency tag used in Cenderawasih Bay cost only $4.

"It's good enough for a start since we have little information about the behaviour of whale sharks here," he said.

Marine biologist Mark Erdmann, who joined the expedition, said it was "fairly impractical to swim after the giants with a receiver wand under water".

"What makes this tagging possible in Cenderawasih Bay is the unique habit this population has of aggregating at... fishing platforms to feast upon the small silverside baitfish that the fishers are catching," he said.

Whale sharks, the world's largest fish, are classified as "vulnerable" by the International Union for the Conservation of Nature (IUCN.)

http://news.yahoo.com/indonesias-unique-whale-sharks-pet-tags-103323726.html?_esi=1

Group of 25 whale sharks off Western Australia

Whale shark discovery prompts caution

May 2012. The group of at least 25 whale sharks was spotted earlier this month by recreational boater Luke Ryan feeding on krill west of the Muiron Islands, and later confirmed by Western Australia Department of Environment and Conservation (DEC) marine rangers.

DEC Exmouth whale shark conservation officer Emily Wilson said it was the first time feeding aggregations of more than 20 whale sharks had been recorded in the Ningaloo area, although aggregations of this size have been observed in other parts of the world.

"At this stage, it was clear from observations and plankton samples collected the sharks were in the area due to the abundance of food on the surface of the water, however we are unsure if this feeding aggregation is a unique event or a common occurrence at night when no-one is there to witness it," she said.

"This discovery is very exciting as it may help us unravel many mysteries about the whale shark population at Ningaloo and how it links with other populations around the world. Whale sharks are a threatened species and they need to be in prime health in order to reproduce, so disturbance needs to be minimised so that normal feeding behaviour can be maintained.

The DEC is asking boaters to take extra caution around a newly discovered aggregation of whale sharks off the Ningaloo coast. The whale sharks were feeding at the surface, making them vulnerable to boat strike.

"DEC asks that recreational and commercial boat operators watch their speed around the Muiron Islands Marine Management Area and maintain a good lookout at all times."

http://www.wildlifeextra.com/go/news/whale-shark-ningaloo.html

Pakistan Whale Shark's Death a Mystery

Video of a dead whale shark being pulled from the sea off of Pakistan raises more questions about the school-bus-size fish's demise than it answers, scientists say.

Pakistani newspaper The Express Tribune posted video on Tuesday (Feb. 7) of a crane hauling a whale shark carcass onto a pier in Karachi. According to the newspaper, the owner of the nearby Charai Fishery, spotted the animal floating "unconscious" 10 days earlier, 93 miles (150 kilometers) from the fishery. 

But sharks don't fall unconscious, said Bob Hueter, the director of the Center for Shark Research at Mote Marine Laboratory in Florida. And if they stop swimming for any reason, they aren't likely to bob along with the currents.

"If and when they die, they don't float, they sink," Hueter told LiveScience. "So to have one just kind of wash up is very rare. I can only think of a few cases over the years around the world where this is happened."

Continued:  http://www.livescience.com/18376-pakistan-whale-shark.html

Whale Sharks Use Geometry to Avoid Sinking

ScienceDaily (Nov. 27, 2010) — They are the largest fish species in the ocean, but the majestic gliding motion of the whale shark is, scientists argue, an astonishing feat of mathematics and energy conservation. In new research published November 25 in the British Ecological Society's journal Functional Ecology marine scientists reveal how these massive sharks use geometry to enhance their natural negative buoyancy and stay afloat.


For most animals movement is crucial for survival, both for finding food and for evading predators. However, movement costs substantial amounts of energy and while this is true of land based animals it is even more complex for birds and marine animals which travel in three dimensions. Unsurprisingly this has a profound impact on their movement patterns.


"The key factor for animal movement is travel speed, which governs how much energy an animal uses, the distance it will travel and how often resources are encountered," said lead author Adrian Gleiss from Swansea University. "However, oceanic animals not only have to consider their travel speed, but also how vertical movement will affect their energy expenditure, which changes the whole perspective."

For the past four years, Adrian Gleiss and Rory Wilson, from Swansea University, worked with Brad Norman from ECOcean Inc. to lead an international team to investigate the movements of whale sharks, Rhincodon typus, at Ningaloo Reef in Western Australia. They attached animal-borne motion sensors, accelerometers, to the free-swimming whale sharks to measure their swimming activity and vertical movement, which allowed them to quantify the energetic cost of vertical movement.

The team's data revealed that whale sharks are able to glide without investing energy into movement when descending, but they had to beat their tails when they ascended. This occurs because sharks, unlike many fish, have negative buoyancy.

Also, the steeper the sharks ascended, the harder they had to beat their tail and the more energy they had to invest. The Whale Sharks displayed two broad movement modes, one consisting of shallow ascent angles, which minimize the energetic cost of moving in the horizontal while a second characteristic of steeper ascent angles, optimized the energetic cost of vertical movement.

"These results demonstrate how geometry plays a crucial role in movement strategies for animals moving in 3-dimensions," concluded Gleiss. "This use of negative buoyancy may play a large part in oceanic sharks being able to locate and travel between scarce and unpredictable food sources efficiently."

http://www.sciencedaily.com/releases/2010/11/101124214717.htm