Starfish - Asteroidea

We all know these pretty little stars as 'starfish', but recently scientists have begun to correct their name to 'Sea Stars' as the organisms do not come under the kingdom 'fish' but they come under the kingdom 'Echinoderm' closely related to Sea Urchins and Sea Biscuits.

Sea stars are fairly unique in that they're found almost everywhere on the ocean floor from shallow tidal beaches to deep sea.

To cover this massive ocean space, there are at least 2,000 species of Sea Stars. Most having five arms, but some can have 10, 20, even 40.

These critters are sort of magic in a way. If a predator were to break of one arm (or shed it in defence), this arm can not only be re-grown on the body, but if a tiny segment of that arm survives, some species can re-grow a whole new body around that piece. This is because some Stars store their vital organs in their arms rather than central bodies.

Sea Stars aren't all pretty shapes and magic powers though. They have some pretty gruesome table manners. Rather than doing the same as almost every other organism on the planet, (entering food into the mouth then digesting it) they decided to come up with a unique technique for dinner time. The National Geographic has a nice explanation for this: "Most sea stars also have the remarkable ability to consume prey outside their bodies. Using tiny, suction-cupped tube feet, they pry open clams or oysters, and their sack-like cardiac stomach emerges from their mouth and oozes inside the shell. The stomach then envelops the prey to digest it, and finally withdraws back into the body."

Another crazy fact, from National Geographic, is that Sea Stars also have no brains and no blood. They have seawater circulating through their bodies rather than blood.
To keep up with the weird theme, some Sea Stars are hermaphrodites, meaning they can produce both sperm and eggs. These are made in an organ called an "ovotestis" coming from "ovary" and "testicle". These then fertilise to become little sea stars. Other species start as males, then as they grow older they become female. If this grown female were to then split into two, the re-growing two would both be male until they reach a certain age again.

These pretty stars aren't all weird adaptations though. Some species are among the most invasive marine organisms. An introduced species from Japan has been destroying coral reefs in Northeast Australia and French Polynesia. They are expected to have been introduced as larvae in off run from Japanese ships.

Currently Sea Stars are unaffected by pollution or human impacts. But scientists believe that high levels of ocean acidification (too much carbon dioxide in the ocean) will stunt the growth of these organism's skeletons. And also some species are unable to survive in water with high temperatures, which may happen with global warming.
But, on the bright side, for now they're a healthy group of marine organisms holding up the food chain whilst being pretty.
That's what we like!

Puffer Fish - Tetraodontidae

These little guys are the puppies of the ocean. Their big eyes and round bodies create the illusion that they are completely innocent and harmless.

Think again.

These are the second most poisonous vertebrates in the world.

One adult Pufferfish contains enough poison to kill 30 adult humans. Not so innocent?

They have this crazy elastic skin/bodies that can double, or even triple in size on demand. This stops predators because their prey is suddenly too big to swallow.

Scientists think Pufferfish adapted this because they were too slow and clumsy to swim away from their predators, which is likely true. They have tiny little fins that make precise but slow movement.

If the predator managed to catch the Pufferfish before it inflates, it would soon regret it's decision because Pufferfish contain a chemical called Tetrodotoxin which is foul tasting and in most cases poisonous to fish and humans.

Tetrodotoxin is found mainly in the ovaries and liver, but can be traced through other parts of the body also.

Apparently sharks and some large fish are immune to the pufferfish's poison, and in some places in Japan, farmers have bred un-poisonous Pufferfish by limiting their diet to certain foods.

In Japan, Fugu(Pufferfish) is a delicacy that is only prepared by trained and licensed chefs because if prepared wrong, it could kill customers, which happens annually up to 44 times in Japan alone. 

Tetrodotoxin paralyses the victims muscles, while the victim stays fully conscious and eventually dies from asphyxiation which is when the body can't get enough oxygen.

Not so cute.

There are 120 species of Pufferfish, and some can grow up to 100cm in length.

These fish are only found in tropical seas.

All species of Pufferfish can move their eyes independently and some are similar to chameleons in that they can camouflage into their surrounding environments.

Pufferfish eat algae and small invertebrates  Some larger species break open clams, mussels and shellfish with their four big teeth (which is where their scientific name comes from).

Pufferfish mating has never been witnessed in the open ocean, but divers and scientists have come across male Pufferfish creating spherical shapes in the sand on the seafloor which is believed to attract the female and serve a safe place for her to lay her eggs.

Some species of Pufferfish are considered threatened by pollution , due to habitat loss (coral reefs etc), and over fishing. But most populations are stable and not in need of urgent action.

Refreshing to hear hey?

If we keep up the good work all marine species will be as bright as this one!

Hector's Dolphin - Cephalorhynchus hectori

New Zealand is home to only two endemic mammal species, the short tailed bat, and the Hector's dolphin.

The population of Hector's dolphins, due to water levels rising and ice ages, has divided into two species. The north island group called "Maui's dolphin" and the south island holds the name "Hector's".

The Maui's dolphin is the rarest marine mammal in the world with only 55 animals over one year of age estimated for the whole population. And the Hector's only grows to 1.5 metres in length and is one of the world's smallest marine mammals, but has a larger population, estimated at 7,270.

Maui's dolphins are only found on the west coast of the North Island, and Hector's have been seen regularly on the north west coast of the South Island and amongst Banks Peninsula on the east coast of the South Island.

I have been extremely lucky to have grown up in Lyttelton Harbour, catching the ferry to and from my home town. All my life I've been aware of the Hector's dolphins, as they regularly come right into the harbour and swim around the boats.

Black Cat Cruises takes trips out Akaroa and Lyttelton harbours to swim with and view the dolphins, encouraging the conservation of these animals and teaching tourists and locals about what is around them.

These dolphins are the only dolphins found in New Zealand with a rounded dorsal find which makes them easier to spot.

Males are smaller and lighter than females.

They life for a maximum of 20 years.

Females reproduce from nine years of age, and even then only have one calf every two to three years. Generally a female dolphin will give birth to four calves in their lifetime, keeping population sizes extremely low.

Meals for the Hector's dolphins includes Ahuru, Yellow-Eyed Mullet, Kahawai, Arrow Squid, Herring and Red Cod. These dolphins are also a snack for many shark species and Orca Whales.

Like all other dolphin species, Hectors and Maui dolphins use echolocation, but not constantly. Which is thought to be why they get caught in fishing nets so often.

The biggest threat to Hector's dolphins is set-nets or gill-nets. These nets are made of fine netting which is un-detectable for the dolphins. They get caught in the nets and are stuck underwater and are unable to reach the surface for oxygen, and drown.

It has been estimated that these nets kill 110-150 dolphins each year, and as you read earlier, the small numbers in the populations can no longer afford to lose that many.

There have been two Marine Protected Areas created for the Hector's dolphins, the first in and around Banks Peninsula in 1988, and the second on the West Coast of the north island in 2003. Though the numbers are still expected to drop as these areas don't reach as far offshore as the dolphins do.

While Helen Clark was the prime minister a few more restrictions were made to protect the dolphins and reduce set-nets, but it appears that since then no further changes have made. These changes are desperately needed to reduce chance of extinction for these little dolphins.

Please do your bit!

Sharks - Selachimorpha

What makes a fish a shark?

-cartilaginous skeleton (not at strong as bone, the structure in your ears and nose),

-five to seven gill slits behind the eyes/head,

-pointy pectoral fins which are separated from the head.

There is said to be more than 470 species of shark lurking in the oceans today, some of which have been ruling the ocean for 420 million years and 200 of the 470 species are in critical danger of extinction.

Of these 470 species, there are some which grow up to around 12 metres in length (Whale Shark), and the smallest only 17 centimetres (Dwarf Lanternshark).

TEETH:

Shark's teeth grow in rows and are only attached to their gums, when time for replacement, they move forwards in a conveyor like way towards the opening of their mouth. Some sharks will lose up to 30,000 teeth in their life time.

JAWS:

Sharks jaws are not attached to the rest of their cartilage. This comes in handy for Great Whites when biting their prey. They can push their jaw forwards, almost as far as their nose, to grab their prey. As shown in this picture:

FINS:

Sharks usually have 8 fins altogether. These fins mean that the sharks can only swim forwards. If met with an object face on, the shark has to drift away, not swim backwards.

Without fins sharks cannot swim. They propel movement, keep balance and steer direction.

The Mako shark is the fastest shark and can swim up to 50kph.

Sharks have been given a sinister image due to the movie "Jaws" and their inhumane appearance of which we can't find a way to relate to or understand.

This fact seems to make people less worried about the population numbers and lives of sharks, and more accepting of the huge wastage and mass murder these organisms are facing.

In reality more people are killed by hippopotamuses than sharks each year. 3,000 Hippo attacks and only 6 Shark.

The largest threat to sharks is us, mankind, if you've ever paid for shark fin soup, that's your choice but just know that you're supporting the possible extinction and may want to re-think what you order next time you're in your fave asian restaurant.

Many Shark fisheries will catch the sharks and slice off their fins while they're still alive, to then throw away the remaining 98% of alive shark back into the sea. They do this because;

1. The body of a shark is not a delicacy or great to eat,

2. It saves precious time not killing the animals,

3. Less fuel is needed to transport the fins back than the heavy bodies of the sharks and

4. They can store more fins on the fishing vessel.

This practise is illegal in 98 countries around the world including Australia, U.S, Canada, South Africa, Mexico, Brazil, European Union, Guam, Guatemala and Belize.

On the other hand, shark finning is still legal in New Zealand as long as the sharks are killed before having their fins removed.
People haven't stuck to this law though, and this is video evidence that live shark finning took place in the Marlborough Sounds (Shark Finning Marlborough).

Around 24,000 tonnes (the same as 300,000 people) of shark meat are taken from New Zealand waters every year. More than 100 million sharks are caught around the world every year. 

2 species of shark, (of the 115) in New Zealand waters, are protected. They are the Great White and Basking.

Why fin sharks?

It's not the New Zealand people that are demanding these fins, it's south-east asian countries that use it in their shark-fin soup. 1 kilogram of shark fins exported from New Zealand can sell for up to $1200, and annually we make around $4.5 million from this practice.

The main reasons nothing has been done to stop this in New Zealand is firstly because the government won't see a problem if huge money is involved, and secondly because nobody knows enough about sharks to know how many there are, were and are dying. Population numbers are just guessed, so it's hard for conservation to know if urgent protection is needed.

On sunday the 10th November, the government proposed that Shark Finning is banned in New Zealand waters, but this proposal won't take effect for at least another 2 years. No one knows if the population numbers can hold up until then, as the fishing numbers are increasing rapidly.

If you have a minute and disagree with shark finning in New Zealand fill out Green Peace's submission to stop it immediately.

(Submission)

Thanks fellas.