5 Reasons why sharks are in trouble!

Photo Credit: National Wildlife Federation

There are 5 main reasons why Sharks are in trouble today, and all of them are man-related. 

1. Commercial Shark fishing - Fishing for Sharks has been around for decades and in the past 60 years has depleted populations drastically. Shark fishing occurs worldwide and they are hunted for their fins, liver oil, cartilage and meat.
2. Shark bycatch - Bycatch is when sharks are accidentally caught in commercial fishing nets. Unfortunately they are then often killed. This is usually unreported and illegally carried out, causing a decrease in shark numbers over the years. 
3. Consumer demand - Worldwide shark fins are in high demand, especially in Asia where they are used for the delicacy Shark Fin Soup. Over the years this industry has increased in value from $400 to $500 million a year. 
4. Lack of regulation - Unfortunately these species are not as protected as they need to be, meaning that shark fishing is still taking place across the world. 
5. Misunderstanding - These giants of the sea are very misunderstood creatures and, as a consequence of movies such as the famous Jaws, get very bad press. In reality, Sharks play a very important role as the oceans top predators and without them a lot of marine ecosystems would suffer. 

Disease causing starfish to turn to goo

Photo Credit: Melissa Miner - LiveScience

Researchers have discovered a disease that is killing hundreds of starfish along the East and West coast of the United States. 

The disease, which has been named Sea Star Wasting Syndrome, causes lesions and eventually limb loss, effectively turning them to goo. Researchers have been unable to figure out exactly what is causing the disease and are unsure whether it is bacterial, viral or a combination of effects that have been caused by environmental stressors such as increasing water temperatures.

This disease may also be a consequence of our behaviour as the ocean absorbs about half of the carbon dioxide that man releases, causing the pH of the water to drop to more acidic levels.
This increased acidity may be causing the shells and skeletons of marine animals to dissolve, including starfish who have a calcium-based skeleton. 
You can read more about this here where some researchers from my local Marine Laboratory have studied the affects of global warming on marine wildlife. 

Sea star wasting syndrome is not thought to be spreading to other marine species, however this drastic loss of starfish may have serious detrimental effects on marine ecosystems. It has been recorded that this disease has killed up to 95% of some populations consisting of hundreds of individuals.
Some species of starfish, such as the West Coasts Ochre sea star and the Sunflower sea star (the largest sea star on earth) are thought to be keystone species, meaning that without them the ecosystem they exist in will simply not exist, killing every other species that relies on them to survive. 

This has occurred in sea stars before and populations have bounced back from it, so it is not 100% certain that this disease will be catastrophic however it will certainly be kept a close eye on. Some starfish are important indicator species, meaning that they help us to find out what is going on in the environment and a loss of these indicators may suggest something is going wrong elsewhere.

Blinky the three-eyed crab

Photo Credit: Gerhard Scholtz, Peter K. L. Ng and Stephen Moore

This strange creature is Blinky, a three-eyed freshwater crab that was found in the Hoteo river on New Zealands north island. Many of you may have heard of Blinky the three-eyed fish from The Simpsons but, unlike the fish whose deformities were comically blamed on nuclear waste pollution, this little critter is likely to be the result of conjoined crab twins.

German researcher Gerhard Scholtz and colleagues discovered this individual crab during their research in the Hoteo river and at first must've thought they had discovered a new species that defied all rules of biology. Unfortunately, closer examination showed a perfectly reasonable, yet rare, explanation for Blinkys abnormalities.

As well as the obvious three eyes, the little crab also has an antennae-like protrusion on it's back. Scientists believe that this would have been the fourth eye, but the damaged tissue regenerated into this antennae-like deformity.
It was also seen that Blinky had an abnormally small and deformed brain.

Although rare, conjoined twins have been seen in humans however this pattern of deformities has never before been seen in animals.

The number of green sea turtles is declining rapidly due to the pollution caused by oil extraction!
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