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Marine Life & Conservation Blogs

Dragons of the sea

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Guest Blog by Staci-lee Sherwood

The most fascinating and unique characteristic of the Syngnathidae family is how it’s the male that gives birth.  This fish family includes Seahorses,  Pipefish and Seadragon.  Having a head like a horse, Seahorses and Seadragons stand out as a fish species in the marine world.  They are true rock stars of the ocean and a favorite among photographers.  Their tiny size and elusiveness just add to their appeal.

Seadragons

Lesser known than their more famous cousins they are stars in their own right.  These tiny dragons of the sea are larger in size with more color and intriguing patterns.  Found only in southern Australian waters makes them rare.  There are three recognized species, the Weedy, Leafy and newly described Ruby seadragon.

Elusive species are more alluring to scientists because of the chance to be the first to discover something new.  Not much is known about their lives and researchers hope to shed light on these rainbow colored fish.  Their diet consists of tiny mysid shrimp and other zooplankton.  After mating the female deposits up to 300 eggs into the male’s brood patch who then fertilizes and carries them till birth.  Despite their being much larger than Seahorses, which range in size from 1 – 6 inches, they produce  about 1/3 of the eggs. Seadragons range in size from 13 – 18 inches

weedy seadragon: John Turnbull

In 2006 the IUCN listed them as Near Threatened on the Red List.  A lot has changed since then.  As the Seahorse population continues to decline China might look more toward the Seadragon to fill the void.

Seahorses

One fascinating fact about this family of fish they lack teeth or stomachs.  Instead they suck up food through their snout.  Lacking a stomach means food goes in and out rather quickly.  Seahorses will mate for life.  During the courtship dance they curl their tails and change color.  Following the mating ritual it’s the female that deposits up to 1,000 eggs in the male’s pouch.  A handy survival skill, like the chameleon, they can change color to blend into their surroundings.

Diminutive in size they capture the imagination of young and old alike but are in serious danger of going extinct.  Illegal harvesting by China for traditional medicine, used as decoration in key chains and pendants and polluted water have taken their toll.  Without global bans on their exploitation and fierce enforcement the world could lose these horse looking fish.  There are over 40 recognized species globally.

Florida

Many Floridians don’t know we have three species of seahorses, the Dwarf, Lined and Long Snouted.  These are all listed as either Vulnerable or Threatened in US waters.  One of the biggest threats in Florida is the heavily polluted water they live in.  Seahorses live in shallow tropical waters where their habitat is coral reefs, seagrass beds and mangroves.  Unfortunately in Florida the water quality is so poor most of the seagrass is dead while the bleaching of coral reefs has caused their decline.  A bleak future awaits this species.

Seahorses mating in the water column at Blue Heron Bridge in Florida, USA 2022

Globally all species are being pulled from the ocean so Florida populations are at risk of extinction.  A  favorite among divers, some local populations have fan clubs where divers will make special trips hoping to see them.

Australia

The White’s Seahorse, also known as the Sydney Seahorse, has a population decline over 90%.  In 2018 they became the second seahorse species in the world to be listed on the IUCN Red List Status as endangered.  Alarmed scientists took this opportunity to try to save them in a unique way.  Research showed this species uses artificial reefs if natural ones are absent.  David Harasti, Senior Research Scientist at Port Stephens Fisheries Institute, created the ‘Seahorse Hotels’ out of metal cages.  Once placed underwater they soon attract a variety of marine life like Coral and Sponges.  In a matter of weeks they’re covered and start attracting endangered Seahorses.

I spoke with Dr. Harasti about the use of these hotels for other species, especially those found in other parts of the world.  Regarding their use Harasti said the use of hotels may only be suitable for particular seahorse species. We know that they work really well for those species that like artificial habitats such as the White’s seahorse and Pot-belly seahorse in Australia and the Short-head seahorse found in Europe.”

Two tagged juvenile White’s Seahorses living in a hotel 4 months after deployment (Photo: D. Harasti)

Captive bred juvenile seahorses are released into hotels hoping they will breed and help recover their population.  Surveys show adult seahorses have also taken to them.  The project has only been around a few years so it’s too early to tell if the population will rebound.  Illegal harvesting worldwide must stop and laws must be enforced.  With such a steep decline of a species that gets little attention we need real conservation on a global scale now.  Click here to learn more about these hotels and watch some amazing videos https://www.dpi.nsw.gov.au/fishing/species-protection/what-current/endangered-species2/whites-seahorse

South Africa

In 2017 a photograph taken off the eastern coast of South Africa in Sodwana Bay  by Savannah Nalu Olivier showed a new species barely the size of a fingernail.  After viewing the photograph, pygmy seahorse expert Richard Smith realized this was a new discovery.  This is the first pygmy seahorse discovered in the Indian Ocean.  Most pygmy seahorses survive by camouflage among vegetation so what an amazing find to see something so microscopic.  To read the 2020 study click here   https://zookeys.pensoft.net/article/50924/

Photo by Richard Smith, via University of Leeds

Global threats

According to Seahorse Trust the biggest threat to survival is the taking of an estimated 150,000,000 every year, mostly by China, to be used in their traditional medicine.  The use of Seahorses for asthma and impotence has no scientific basis and can be fixed with modern medicine.  Another 1,000,000 are caught for captivity in personal aquariums. There are no accurate numbers for how many end up used in trinkets but it’s estimated 1,000,000 are lost.  At this rate we will push this species toward extinction.

In the past twenty years there has been a global increase in the capture and selling for use in about 80 countries.  Varying degrees of threats exist for different species and different regions.  Somewhere between 50 -97% decline in their population makes for an urgent call to end their use whether for personal and medical reasons.  The world must agree to a ban with enforcement or lose one of its most amazing creatures .

Help save our Seahorses and Seadragons with these do’s and don’ts:

  • Don’t buy dried Seahorses, or trinkets that use them
  • Don’t buy live Seahorses for aquariums
  • Do use modern medicine which is effective and safe instead of Traditional Chinese Medicine
  • Never pollute the water
  • Support conservation efforts
  • Spread the message

To learn how to help Seahorses  https://www.theseahorsetrust.org/

To help conservation in Australia https://www.visitsealife.com/sydney/conservation/


Header Image: Tony Brown

Jeff Goodman is the Editor-at-Large for Scubaverse.com with responsibility for conservation and underwater videography. Jeff is an award-winning TV wildlife and underwater cameraman and film maker who lives in Cornwall, UK. With over 10,000 dives to his credit he has dived in many different environments around the world.

Marine Life & Conservation Blogs

Creature Feature: Whale Shark

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In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

On 30th August it’s International Whale Shark Day! So to celebrate this month’s creature feature is all about the largest fish in the ocean… the Whale Shark!

The biggest shark in the ocean. The biggest fish in the ocean. The Whale Shark lives up to its name. Reaching a whopping 18m in length (potentially more). This is a legendary and beautiful shark.

They are unmistakable. Apart from their size, these filter-feeders have a beautiful patterning on their back. They have a checkerboard of white or yellowish spots on a grey, blue or brown back. It is often compared to a starry sky. In fact. In Madagascar they are known as “marokintana” for “many stars”.

Each Whale Shark’s pattern is unique. Amazingly, software used to identify star clusters from images of space has been adapted to identify individual Whale Sharks!

These sharks are highly migratory. Including journeys of 13,000km (made one way only) over 37 months. Which falls short of the most migratory shark, the Blue Shark. Tagging has revealed that there are regular ‘aggregation sites’. Here, Whale Sharks come together in huge numbers. Several hundred Whale Sharks may come together. To feed at annual, seasonal or lunar fish and invertebrate spawning events. The huge numbers of plankton at these events are consumed by suction. Whale Sharks can hang vertically and feed by sucking and gulping in water which is filtered through gill rakers.

Despite everything we know about them. And tagging studies. We still don’t know where Whale Shark’s pupping or nursery grounds are! We do know they are viviparous, giving birth to live young. Giving birth to up to 300 young.

Although they are protected by international agreements such as CITES and CMS. Unfortunately, Whale Sharks are endangered. They’ve been overfished in many areas for meat. Currently, the tourism industry for this species is booming. If you’re lucky enough to be able to go and see Whale Sharks – then why take a look at our guide for ecotourism.

Finally, if you want to support this majestic creature why not adopt a Whale Shark?

SCIENTIFIC NAME: Rhincodon typus

FAMILY:  Rhincodontidae

MAXIMUM SIZE: 17m – 21m

DIET: Plankton

DISTRIBUTION: Circumglobal, all tropical and warm seas except the Mediterranean

HABITAT: Open ocean to close inshore off beaches

CONSERVATION STATUS:


Banner Image – © Paul Cowell | Shutterstock

In-text Images – © Frogfish Photography


For more amazing facts about sharks and what you can do to help the Shark Trust protect them visit the Shark Trust website by clicking here.

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Marine Life & Conservation

Celebrating the biggest fish in the sea: International Whale Shark Day 2022

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On August 30, the world is showing the biggest shark that lives in our oceans some big, BIG love. Because believe it or not, the biggest fish in the sea needs all the love they can get! Sure they are a shark – but they are the closest thing to a vegetarian that exists in the shark world.  Filter feeders, they eat plankton. While their mouths are 4 feet wide, their throats are the size of a quarter. And before you begin to worry about their 3000+ teeth, you should probably know they are only the size of the head of a match.

It’s hard to believe given the fact they can grow up to 40 feet in length and weigh up to 20 tons, but they are very elusive and proficient in the art of underwater camouflage. In fact, Jacques Cousteau only saw three in his lifetime!

Photo: Simon J Pierce

They are found in all temperate and tropical oceans around the world except for the Mediterranean Sea, and can migrate thousands of miles between feeding areas. They spend most of their lives near the surface, but have been known to dive to depths of almost 2,000m.

These gentle giants are magical – with a unique dot pattern that is specific to each individual whale shark.  Their populations are so low that there is a genetic similarity among all whale sharks worldwide.  Whale sharks play an extremely important role keeping the oceans healthy while also creating sustainable income for local communities through tourism. However, like many other shark species, whale sharks are classified as Endangered on the IUCN Red List of Endangered Species, with declining populations worldwide.  With massive migratory areas that make them difficult to protect, the fact they are often bycatch or targeted for their meat + fins, and as filter feeders that they often consume micro-plastics, whale sharks need all the help they can get.

Photo: Rodrigo Friscione

Here’s everything you need to know about these incredible fish – including how to meet them, how to protect them, and how to celebrate them every day!

Whale Shark Fun Facts:

  • Name: Rhincodon typus
  • Size: 18- 40 feet
  • Weight: up to 20 tons (equivalent to 3 African Elephants, a full school bus or 12,000+ bricks!)
  • Physical features: mouths are 5 feet wide with 3,000 teeth, eyes are as big as golf balls
  • Life Span: estimated 60-100 years
  • IUCN Red List Status: Endangered

1) Love Tropical Waters Both Deep and Shallow

The preferred environments of whale sharks are tropical and temperate waters and all over the world, including both deep and shallow coastal waters and lagoons of coral atolls.

A marine biologist named Eric Hoffmayer recorded the deepest dive yet: in 2008, he monitored a shark in the Gulf of Mexico that descended 6,324 feet. Sharks lack a swim bladder that keeps other fish buoyant, so one idea is that whale sharks free-fall toward the seafloor to rest.

Whale sharks especially love the Philippines. In 2016, the 1000th whale shark was identified in Philippine waters, making the Philippines the third largest known aggregation of whale sharks in the world and the biggest in South East Asia.

2) Endurance Swimmers Who Are Global Travelers

Whale sharks are one of the most migratory species and can travel around 40 miles per day! They tend to prefer different geographic locations at various times of year based largely on water temperature, food supplies and breeding opportunities. Genetic studies show that whale sharks across the globe are closely related which suggests that mating is one of the reasons for such long travels.

It is believed that pregnant females will migrate long distances to be able to give birth near remote islands where baby sharks will be out of reach of common predators.

But they are also slow swimmers (for sharks) usually moving at no more than 3 mph. Their swimming pattern is different than most sharks in that instead of using just the caudal fin for primary propulsion, they use the full posterior two-thirds of their body length.

The record for whale shark migration was 12,000 miles by a whale shark named Anne in 2011. She was tracked making the mammoth migration from near Panama in the southeastern Pacific, to an area close to the Philippines in the Indo-Pacific. Other tracked whale sharks have traveled:

  • Over 8,000 miles from the Gulf of CA, Mexico to Tonga
  • 3,107 miles to the coast of Thailand

Photo: Julie Andersen

3) They Enjoy Alone Time

Whale sharks are usually solitary creatures but come together for months in large aggregations to feed in plankton-dense waters. After feeding, they drift off in random directions, completely disappearing during winter and spring.

4) They Practice Vegetarianism

Whale sharks can eat plankton up to 45 pounds of plankton each day (which is equivalent to  121 cheeseburgers per day). But they also eat shrimp, sardines, anchovies, mackerels, squid, tuna, and albacore. and fish eggs. According to The Nature Conservatory, whale sharks will wait as long as 14 hours for fish to spawn on reefs and then they will swoop in and eat the eggs.

But they also largely have a vegetarian diet, especially when other prey is scarce. Scientists discovered that whale sharks get more than half their nutrients from plants and algae.

5) Each Baby Whale Shark is a Miracle!

Whale sharks are ovoviviparous, meaning they produce eggs that hatch inside the mother’s uterus.  Litters can be up to 300 pups but not all pups are birthed at the same time. That is almost twice as many as any other shark species.

But only one pregnant whale shark has ever been studied and, interestingly, many of these embryos were at different stages of development. Scientists observed that some were still in their egg cases whilst others had emerged but were still in the uterus. This may signify that females are able to store a male’s sperm, selectively fertilizing their eggs over a prolonged period.

Juvenile whale sharks, as docile and vulnerable as their elders, often become prey for other sharks and orcas, so while a female may birth more than 300 pups at a time, survival rates are devastatingly low; females giving birth to multiple litters at different times could increase their survival rate which could be why they have their very own, built-in sperm banks.

Making the birth of a whale shark even more miraculous is the fact that each whale shark’s pattern is as unique as a human fingerprint!

Think You Know Whale Sharks? Click here for a fun way to test your whale shark IQ!

Header Photo: Whale shark in Oslob by Shawn Heinrichs

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