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Whales don’t have scales

October 10, 2010 by Leave a Comment

That’s right. Whales are covered in blubber because they are mammals like you and I. Now the fish in the sea are another story. You might not realize it, but, if you’ve ever had the opportunity to touch a shark they are covered in scales just like other bony fish. There are several main types of scales that cover fish. See if you can figure out which cover sharks.

1.) Ctenoid scales: These scales are comb-like with the ends having small teeth-like structures.

2.) Ganoid scales: These scales are heavy and diamond-shaped.

3.) Cycloid scales: These are round scales with smooth edges.

4.) Cosmoid scales: These scales are very hard and covered in enamel.

5.) Placoid scales: These scales have teeth-like edges. They are different than ctenoid scales because they lack they rounded front.

Scales grow out of the skin and have modified to quite a few different versions over the years. In fact, the feathers of a bird are a type of evolved scale!

Filed Under: Bony Fishes, Fish, Sharks, Skates and Rays

A naturalist’s must-see destination: San Francisco Bay

October 4, 2010 by Leave a Comment
San Francisco Bay © 2004 Matthew Trump

Image via Wikipedia

I thought it might be interesting to take some time each week over the next few months to get to know a particular body of water in different regions of the world. For today I am starting off with the San Francisco Bay.

The San Francisco Bay is an extraordinary place that has undergone changes just as big as the state of California itself. The Bay is rather shallow at an average of 18 feet deep. Surprisingly, the watershed for the Bay is just about 40% of the state of California!

San Francisco Bay, Suisan Bay, San Pablo Bay and the Sacramento-Joaquin Delta are the connected inlets that we call the San Francisco Bay waterway, a true urban estuary, with the freshwater coming from the Sacramento and San Joaquin rivers. I think this Bay is particularly interesting since it is a tectonic estuary and has been formed by the movement of the San Andreas fault.

Over recent years (since the time of the Gold Rush when humans really began to alter the landscape of the Bay), the Bay has seen a reduction in over 85% of its marshland. With the diversion of freshwater from north of the Bay (where most of the state’s freshwater is located) to below the Bay (where most of the state’s people are located) the Bay has seen a balance shift affecting many of its natural systems. For more information about how to Save the Bay visit the Save the Bay San Francisco. They have been working to restore the balance of humans and nature in the Bay since 1961.

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Filed Under: Ocean Tagged With:

Who owns the oceans?

October 1, 2010 by Leave a Comment

We all own the oceans … no, wait! No one owns the oceans. Sometimes it is very confusing to answer this question.

Since the third United Nations Convention on the Law of the Sea the jurisdictions of the oceans are known as this:

  • 0-3 nautical miles from the coastline of the country is considered a countries’ territorial seas and are subject to the rules of the country. Invading these waters can be seen as attack.
  • In the United States 0-12 nautical miles is subject to individual state laws.
  • Adjacent to the 12 nautical miles and out to 200 nautical miles is the Exclusive Economic Zone which gives states and/or a countries the “right to explore and exploit, and the responsibility to conserve and manage, the living and non-living resources.”

For more information click here.

Filed Under: Ocean, People, Places Tagged With: , , ,

12 good non-fiction books about fish

September 29, 2010 by 3 Comments
  1. Four Fish: The Future of the Last Wild Food by Paul Greenburg (read a review here.)
  2. Cod: A Biography of the Fish That Changed the World by Mark Kurlansky
  3. On the Run: An Angler’s Journey Down the Striper Coast by David Dibendetto
  4. Giant Bluefin by Douglas Whynott
  5. The Last Fish Tale: The Fate of the Atlantic and Survival in Gloucester, America’s Oldest Fishing Port and Most Original Town by Mark Kurlansky
  6. The Unnatural History of the Sea by Callum Roberts
  7. Tuna: A Love Story by Robert Ellis
  8. The Most Important Fish in the Sea: Menhaden and America: H. Bruce Franklin
  9. The End of the Line: How Overfishing Is Changing the World and What We Eat by Charles Clover
  10. The Empty Ocean by Richard Ellis
  11. 5 Easy Pieces: The Impact of Fisheries on Marine Ecosystems by Daniel Pauly
  12. Striper Wars: An American Fish Story by Dick Russell

Beach Chair Scientist also has list of great movies, fiction books and blogs about the sea!

Image (c) Island Press.

Filed Under: Fish, Random Fun! Tagged With: , , , , , ,

What is bioluminescence?

September 26, 2010 by 1 Comment

Bioluminescence means light (as in ‘illuminate‘) from life (prefix ‘bio‘).

It is produced by a chemical reaction in many marine or terrestrial organisms. The reaction begins with a chemical called luciferase that catalyzes another chemical, luciferin, to then make oxyluciferin and light.

If you see bioluminescence from a boat it is most often tiny dinoflagellates near the surface of the water that begin this chemical reaction once they’re excited. A boat or a passing porpoise can trigger this excitement. On land we are familiar with bioluminescence in fireflies and a glowing fungus, called foxfire.

But, did you know bioluminescence is responsible for illuminating the majority of our habitable world? That’s right, the deep sea is the largest area of habitable space on our planet. A large number of species that utilize this adaptation live in that environment. Here are some images of the inhabitants of the deep sea that use bioluminescence:

Deep sea shrimp, Acanthephyra purpurea

Deep sea fish, Photostomias guernei

Blackdevil angler fish, Melanocetus johnsonii

All images (c) NOAA.

Filed Under: Fish, Places Tagged With: , , , , ,

The “Osprey”, they’re bone breakers alright

September 24, 2010 by Leave a Comment

The Latin name for osprey, Pandion haliaetus, means “bone breaker” and explains quite well how the bird of prey gets his main source of food, fish. Ospreys plummet down from almost 30 stories  above water and use their barbed talons to grab onto mullet, menhaden, or other fish found in estuaries. These barbs can be thought of as backwards facing scales that allow them to be very precise in clutching their food source.

Image (c) grit.com

Filed Under: Birds Tagged With: , ,

Can you tell what type of whale is under the surface by the spray it produces above the surface?

September 23, 2010 by Leave a Comment

Yes. For instance, the sperm whale will blow forward and to the left. The vapor will be about 6 feet tall. Right whales and bowhead whales will have a v-shaped blow. The right whales will be about 15 feet tall while the bowhead whales will be higher at 21 feet tall. Humpback whales have a low and wide spray. It may reach up to 9 feet. Lastly, the mighty blue whale has the strongest and most distinct spray shooting straight up to almost 21 feet tall.

Filed Under: Marine Mammals

Test your knowledge: Social science of the ocean

September 21, 2010 by Leave a Comment

Here are some more sample questions from the Consortium for Ocean Leadership‘s popular National Ocean Science Bowl. These questions come from the Social Science section.

Good luck!

1.) How often have men descended to the Challenger Deep? a) Once b) Twice c) Three times d) Never

Map showing the location of the Mariana Trench...

Image via Wikipedia

(The Challenger Deep is 36,000 feet deep along the Mariana Trench.)

2.) In 1933, the US tanker Ramapo encountered the highest wind wave ever measured reliably. How tall was this wave? a) 12 meters b) 34 meters c) 42 meters d) 54 meters

3.) Which of the following is NOT an example of human-made structure designed to stabilize the shoreline? a) Breakwater b) Jetty c) Tibia d) Pier

Answers can be found here.

Filed Under: Places, Random Fun!, Test Your Knowledge

Does the ocean freeze?

September 19, 2010 by Leave a Comment

That all depends upon the salinity of the water. For more information about salinity, or how much salt is in the ocean, click here.  Generally the higher the salinity the lower the freezing point. So the ocean of the Mid-Atlantic, with an average salinity of 32 ppt, doesn’t tend to freeze when the rain turns into ice. The polar ice caps however have the distinction of having a lower salinity and being near very freezing temperatures.

Filed Under: Ocean Tagged With:

What is red tide?

September 16, 2010 by Leave a Comment
a red tide

a red tide (Photo credit: Wikipedia)

About six years ago I went to a wedding on the Gulf of Mexico which was extraordinary except for the occurrence of red tide. Don’t get me wrong, the guests and bride and groom all had a fabulous time despite the red tide. How did it affect us? We were not permitted to swim in the ocean and made the best out of it by playing run the bases on the beach. We could only do this for a little while since it actually affected our breathing and so we took a lot of breaks for margaritas.

It got me wondering what is a red tide? From my research it seems that red tides are not always red and have nothing to do with tides. Scientists are trying to wash away the term red tide and use the term harmful algae bloom (HAB) which explains a bit better about what happens during these occurrences. During a HAB on the Gulf of Mexico there is a high concentration of microscopic marine algae known as Karenia brevis. This is not the only algal culprit to an HAB, but, it is the most frequent. In the Gulf of Mexico the algae Alexandrium fundyense has been known to cause serious damage to local fisheries. In low concentrations these algae is not harmful. But, with high concentrations fish suffocate after it paralyzes their central nervous system. Also, many shellfish that filter water can accumulate the toxins and become inedible to eat.

How harmful algal blooms occur is still under debate. It can be a natural or man-made occurrence.

Do you have another great question? Email info@beachchairscientist.com and let me know what you always ponder while digging your toes in the sand!

Filed Under: Algae (Seaweeds), Ocean Tagged With: , , , , ,