Sea Turtle Hatchlings

Baby sea turtles, hatchlings, have a very tough life. Mom digs a nest, deposits her eggs (about 100), and then leaves. She may lay eggs four to six times a season. The eggs are about the size of ping pong balls and a little more flexible (they have a ways to fall).

Later, the hatchlings have to fight their way out of the nest and through sand to the surface... and then make their way to the ocean. One of the biggest threats to hatchlings is photopollution. For more information about how lighting affects baby turtles, click here.

 

For other threats to Sea Turtles as hatchlings or as adults, check here or here. 

Beginning Reptiles

In class we have been working on final projects and today we began discussing reptiles!

There are four types of reptiles found in saltwater, but they aren't that common. Marine Iguanas are the only marine lizard and are only found on the Galapagos Islands. They dive into the cold seas to feast on algae and as a result have to spend a lot of time basking on rocks to warm back up. They expel salt through their nostrils via salty snot rockets.

Sea Snakes are found in the Indo-Pacific and are venomous, but not aggressive - meaning they can kill you, but aren't likely to attack you. They have really big lungs to hold their breath for a long time and special nose flaps to keep the water out.

Saltwater crocodiles can be found in the Florida Keys, but are more common in Australia. These menacing reptiles are especially scary because they are found on beaches where people want to swim.

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Shark Conservation

Today we discussed conservation of sharks. Millions of sharks are killed each year by humans. Some are caught by sport fisherman, some are harvested for oils, meats, and other things; many of them are being harvested for their fins. Finning wastes 95% of an animal, and the sharks are often tossed back in the ocean alive after being finned to die a slow painful death. For more information, click here.

The fins are harvested for shark fin soup. Shark fin soup is considered a delicacy in some countries and can sell for upwards of a hundred dollars a bowl.

The next thing we talked about was shark attacks. Most shark attacks are actually provoked by humans. Other shark attacks like bump-and-bites and hit-and-runs are the shark investigating a human to see if it is something good to eat. Once the shark tries it, it finds it doesn't like humans, it will swim away. Unfortunately for us humans, we are not so tough and kind of squishy and shark attacks damage us.

build a fish interactive

Build a Fish!
http://sv.berkeley.edu/showcase/flash/fish.html

Skates and Rays

Today in class we talked about skates and rays. Skates and rays are depressed relatives of sharks that often spend most of their time on the benthos. (There are a few exceptions like manta rays pictured in the upper right)

Skates and rays are really similar and often hard to tell apart. Some rays look like flat sharks and some flat sharks look like rays, so we are going to be general in identifying skates and rays. In general, skates have fins on the tips of their tails.

Only rays can have stingers, and not all of them do. They can have 1 to 3 stingers from 5 to 15 inches long. See the picture below.

I often get asked about Steve Irwin, the famous Crocodile Hunter when we talk about stingrays. Yes, Steve Irwin was killed by a stingray, but his type of accident was very rare. Steve got stabbed in the heart which injected venom right into an important organ. Also, he removed the barb which caused just as much damage going in as it did coming out because of the sharp serrated edge. For more information about Steve Irwin's death check here and here.

Still worried about shark attacks? Check the newest stats here at the Florida site.

Shark Review

We are finishing up sharks and finishing up final projects. Final Projects are due Tuesday November 30th, after Thanksgiving, but students will get 5 extra points for turning in a quality project before Thanksgiving Break. (It's not worth it to turn in a substandard project before Turkey time)

Try this review of Shark Anatomy. It covers what we did and a bit more. MsJ got a 95% in 38 seconds.

Try this quick Shark ID game. MsJ got a 75% the first time because of a reef shark!

Check out Nate's shark model with the strong man fighting his way out!

Shark Senses

Today we learned about shark senses. Sharks have a large brain to help process the sensory overload they must get from the SEVEN senses they have. They have the five we have plus a lateral line (pressure and vibrations) and the ampullae of lorenzini (electro-reception).

Follow this link for a cool interactive about how shark jaws stick out when they attack their prey! The interactive is down at the bottom.

If you are doing a final project on a shark... check out this new link! www.shark.ch

And once again... one try only... how much do you know about sharks? MsJ scored a 1467. Try Shark Weeks Ultimate Shark Challenge to see how much you know. Please limit yourself to 15 minutes.

Fe fi fo fishies!

Students have finished up fish for now and took their test Friday. Students have excelled at the many fishy challenges set before them and it would be impossible for me to say who the winners were of the many challenges we have completed.

Next up is SHARKS! Great whites in the waters off the coast of South Africa leap out of the water to chase the fur seals they want to eat that also leap out of the water.

Try Shark Weeks Ultimate Shark Challenge to see how much you know. (Play only once) MsJ scored 1370.

Fishing Methods and Sustainable Harvesting

Monday and Wednesday we discussed fishing and seafood harvesting, the good, the bad, and the just plain ugly.

The truth is that our oceans are being fished to extinction and emptiness. We are harvesting more and more fish from smaller and smaller populations. What is a person to do that wants to eat seafood, but not hurt the environment?

BECOME AWARE. Most people do not know where their seafood came from or how it was caught.

How it was caught makes a big difference. Different fishing methods have pros and cons for the environment and regarding bycatch (fish and other organisms like sharks, sea turtles, sea birds, and dolphins, that are caught, often killed, and not really wanted).

One of the biggest things to avoid is any kind of imported shrimp. Imported shrimp are either caught with destructive trawl nets that destroy habitats and that do not have TEDs that allow turtles and dolphins to escape unharmed or they are farmed in aquaculture plants that are built on destroyed mangrove forests that then leach pollution and kill nearby coral reefs.

The United States requires all shrimp trawlers to be outfitted with TEDs and regulates where they can trawl. The US has higher standards for pollution laws and laws protecting shore habitats that result in less damage to the environment. Choose US shrimp ONLY!

If you would like more information - check out SeafoodWatch, a non-profit organization that independently evaluates fisheries for their sustainability and environmental impacts.

This article also has some really nice information and photos. Sustainable seafood.

Fishing Methods and Sustainable Harvesting

Today we discussed fishing methods and the advantages and disadvantages of different methods. Netting is the most popular method of commercial fishing because a lot of fish can be caught in short amount of time without a lot of effort.

One the major problems with most commerical fisheries is the amount of bycatch. Bycatch is anything caught in the net that you do not want. This could include edible fish that your company is just not equipped to process.

Most organisms brought up in nets as bycatch do not survive because they are crushed or drowned. Sea turtles and dolphins sometimes get swept into nets and drown because they cannot make it to the surface to breathe.

Most scientists and fisherman agree that the oceans have been and are being overharvested. People may not like regulations, but without regulations, many fish species that we used to commonly consume would be extinct.