#39 Clown Fish

Weird Fact: Clownfish change from male to female

Clownfish and sea anemone

Clownfish and a purple and white sea anemone

The ocean floor is full of weird and wonderful creatures, perhaps none more famous than the clownfish. Thanks to the spotlight that Disney’s Finding Nemo put on this little guy, many people are taking a closer look…and this unique fish deserves all the attention he gets.

What are Clownfish?

The familiar orange and white clownfish is only one of the twenty-eight species of amphiprion, also known as Anemone Fish due to their symbiotic relationship with sea anemone. Clownfish size ranges from 10 to 18 inches at full maturity and they vary in color, including shades of pink, red, black and maroon.

The orange and white striped ocellaris clownfish may be the most recognizable type of clownfish but all amphiprion are striking, a feature which appears to serve a purpose – attracting dinner for the sea anemone and cleaning up on the leftovers.

How do clownfish change sexes?

Clownfish are sequential hermaphrodites, which means that their life cycle is a little complicated. All types of clownfish develop first as males and mature into females only when they reach the top of the group hierarchy. Hermaphroditism is not rare in fish and marine life, but in 75% of sequential hermaphrodites, the organism begins female and becomes male upon maturity…not so with our friend, the clownfish.

There is a single breeding pair and a number of smaller males within any group of clownfish. Should the female die, the most aggressive male will gain weight, change to female and assume her role. The next largest of the younger fish will then take his place as the breeding male in the group.

 

Dr Justin Rhodes, Associate Professor of Psychology from the University of Illinois studies Clownfish.  He does a fantastic job of explaining what happens when they change from male to female.

 

Where do clown fish live?

Anemone Fish live in shallow seas and reefs. They thrive in warm water environments like the Indian and Pacific oceans as well as the Great Barrier Reef. Their habitat is easy to recognize because wherever sea anemone are, clownfish will be close by. One of the most interesting facts about the clownfish, beyond its gender-bending, is the relationship it has with the sea anemone, a stationary omnivorous sea creature with poisonous tentacles.

There are various theories as to how the clownfish and anemone can live in such close proximity, with clownfish making a home where other fish go to die. Some scientists believe that a mucus which covers the skin of clownfish prevents the poison from penetrating. However, a peculiar behavior has been noted in clownfish that may explain their immunity. When approaching an anemone for the first time, clownfish have been observed brushing up against the tentacles with its body again and again. It is possible that this little dance allows them to build up immunity to the anemone’s toxins.

Once the clownfish has taken up residence in the anemone’s deadly tentacles, a kind of mutualism takes place. These fiercely territorial fish protect the anemone from possible prey but also attract other small fish which the anemone can sting and then eat. Clownfish will eat plankton, crustaceans and algae but their diet primarily consists of the sea anemone’s leftovers. Should the anemone lose the use of a tentacle, the clownfish will eat that too.

Are clown fish endangered?

Currently, Clownfish are considered a threatened species. However, in 2012 a petition was filed to request that they be added to the endangered species list. The threats against them include; global climate change, ocean acidification (pollution) and the marine ornamental trade. A whopping 43% of global aquarium trade is in clownfish and 75% of those fish are captured in the wild. For this reason, it may be best to leave Nemo where he lives among the coral reefs and sea anemone and love him from afar.

Copyright © Mark Beselt


#38 Bay of Fundy Tides

Weird Fact: Canada’s Bay of Fundy has the highest tides in the world.

Where is the Bay of Fundy

The Bay of Fundy is located between the state of Maine and the Canadian provinces of New Brunswick and Nova Scotia.


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How High are the Tides:

In some parts of the Bay of Fundy, the difference between low tide and high tide can be as much as 50 feet.  It is estimated that over 110 billion tons or over 20 cubic miles of water flow in and out of the bay every 24 hours – more water than all of the world’s rivers combined discharge into the ocean in the same time frame.   In fact, the tide comes in with so much force that it actually causes the local rivers to run backwards – a phenomenon called a tidal bore.


What Causes the High Tides

The world’s highest tides are caused by a combination of two factors. The shape of the Bay of Fundy is a natural funnel lined with rock cliffs which gets shallower and shallower as you move father up the bay. This shape gives the tides a sloshing effect similar to what you get in the bathtub.  The second factor that contributes to the tides is the synchronization of two tidal pulses…the Gulf of Maine tidal pulse and the lunar pulse.  Combine the two tidal pulses with the shape of the bay, and over 20 cubic miles of water and you get the highest tides in the world.

How much Energy is created by the Bay of Fundy tides:

The Annapolis Tidal Power Plant in the Bay of Fundy has a generating capacity of 20 megawatts and is one of only three operational tidal power plants in the world.  This pales in comparison to the total amount of energy created by the tides which some researchers estimate could be as high as 50 gigawatts.  To put that number in perspective the largest power plant in the world is the Three Gorges Hydroelectric dam in China with a total generating capacity of 22.5 gigawatts.  The Bay of Fundy tides create at least twice as much energy every day; however, researchers believe that only 7 to 10 gigawatts is harvestable.   This is a smaller number, but still 10 times greater than the generating capacity at America’s most famous nuclear plant, Three Mile Island.

Working in the Bay of Fundy is expensive and challenging.  It will likely be a few years before power companies figure out how best to capture the power.  In the mean time, the Bay of Fundy Tides are an amazing site that must be seen to be fully appreciated.

Copyright © Mark Beselt