by Eric Austin Yee
Whale and dolphins are not the only animals our whale watching guest here at Dana Whale Watch find during our excursions. One of the most common yet, unusual animals we see is the Mola mola, also known as the ocean sunfish or mola. Molas are found worldwide in tropical and temperate waters. The mola is a very unusual fish that most of our guest have never seen or even heard of. Gasp of disbelief and amazement can usually be heard when we spot the unique molas.
When our guest first see the mola, they can’t usually figure out what they are looking at. The gray disc shaped body, long dorsal and anal fins and lack of a true tail make the mola very intriguing. At a distance it is common to mistake the tall dorsal fin of the mola for one of a shark slicing thru the surface of the ocean. A mature mola is capable of reaching up to 9 feet in length and weighing up to 2,000 pounds. There are reports of molas weighing up to 5000 pounds, making it the heaviest bony fish in the world. Being the heaviest bony fish doesn’t keep the mola safe from predators. California sea lions, sharks, marlin and orca have been known to prey on molas. Being big and heavy doesn’t been mean the mola has a huge mouth to go with it. The mouth of the mola is small compared to its body and contains fused teeth. Molas usually feed on soft bodied pelagic invertebrates such as jellies, tunicates and salps.
Molas are also commonly called the ocean sunfish, most likely because of its “sunning” behavior. We spot mola usually laying on their side, right at the surface of the ocean. While the mola lays in this position, it is not uncommon to see many types of parasites clinging to the molas thick skin. Various types of animals will actually clean the parasites off the mola while in this position. Gulls have been known to eat the parasites off molas, along with fish such as senoritas and various types of perch. Recent studies have shown that the mola might also be “sunning” to warm its body before and after deep dives. Molas were once thought to be a strictly pelagic species but dives of up to 2000 feet have been recorded. Also, many bottoms dwelling animals such as brittle star and sponges have been found in the stomachs of molas to reinforce this new finding.
Being the heaviest bony fish is not the only title the mola holds. The molas also holds the title for carrying the most eggs out of all the backboned animals, 300 million! Even though the mola produces so many eggs, the population is considered vulnerable. Threats such as becoming bycatch in gillnets and plastic bags that the mola can mistake for jellies still exist.