Wednesday, August 29, 2012

Holy Mola Mola

Size Comparison
 I often take requests on which animals people want me to write about.  Recently my friend Bernie asked me to write about the Mola Mola.  Interestingly enough this fish happens to be a great part of one of my favorite topics, how animals deal with environmental changes. It is a rare week where you don't hear someone talking about global warming and climate change. I'm not going to discuss whether i believe it is human caused or part of a natural earthly rhythm, well I won't discuss it today. But the truth of the matter is the worlds oceans are showing some of the effects from our changing climate. First some facts about the Mola Mola. In Latin, Mola means millstone which the fish resembles due to its flat shape and grey color. Where its English name Sunfish refers to its basking behavior.
Exhibiting Basking Behavior

The Ocean Sunfish otherwise known as the Mola Mola is the largest bony fish in the world. Fish come in several types but the main two are bony and cartilage. Cartilage fish include sharks. Mola Mola's can weigh up to 2,000 lbs while being as tall as it is wide. They are rather flat in width and exhibit a very unusual basking or sunning behavior.  They will go to the surface of the water and swim on their side. It is believed they swim along the surface on to prep for going into colder deeper water. The Mola Mola is truly a sun-loving fish and enjoys warmer water, mainly tropical and temperate waters. The Mola Mola is able to reach such a large size due to some odd features. Its spinal column contains fewer vertebrae and is shorter in relation than any other fish. The skeleton also contains vast amounts of cartilaginous tissue. Cartilage is lighter than bone and can allow for the fish to grow to sizes larger than any other bony fish. 
I happen to live in the beautiful city of San Diego, and recently there was a sighting of one of this fish nearby. This is highly unusual because we have rather cold water.  It could be an indicator of our ever warming oceans. Jellyfish have blossomed to larger numbers than ever. Jellyfish thrive in warmer water. This has encouraged animals who prey on jellyfish to travel with them. Some of the main predators of jellyfish are sea turtles and the Mola Mola. Warming waters can be beneficial to some creatures but extremely harmful to others. Many fish can migrate and adjust their patterns to a more ideal water temperature.  But what happens to coral reefs or kelp beds?  Both highly specialized environments that don't have the option to pack up and leave. I love to point out animals that are bioindicators.  One of my first posts in this blog was about frogs as bioindicators. I wouldn't consider the Mola Mola a bioindicator (there's just too few of them in the world), but their main food source jellyfish are.

Mola Mola's must consume vast quantities of jellyfish to maintain their considerable bulk.  A jelly fish has very low nutritional value. This also may be one of the reasons the Mola Mola are so temperature sensitive, to maintain such great size on food of poor nutrition is very difficult. Animals trade off abilities in many ways, the Mola Mola has opted for large size, but they have poor temperature regulation. Aquariums have had a hard time keeping these giant fish in captivity. They require large space and often injure themselves bumping into sides of tanks. These fish haven't been studied as indepthly as others. I hope that fish as unique as the Mola Mola have a future ion our oceans. Their future is an uncertain one, but there's always hope.

That's it for now,

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