Clerkin, P.J., Arostegui, M.C., Chiang, Lin S.J., Miller C.D., and Braun C.D. 2024. First telemetry insights into the actions and vertical habitat use of megamouth shark (Megachasma pelagios) in the northwest Pacific. Deep Sea Research Part I: Oceanographic Research Papers 212. doi.org/10.1016/j.dsr.2024.104385
Mega Mystery
New monitoring knowledge is shedding mild on the every day lives of one of the most mysterious sharks in the world, the megamouth shark. This species wasn’t found till 1976 and it was solely as a result of one unintentionally grew to become tangled in an anchor. Since then solely a couple hundred different people have ever been documented. This has left us with many questions on its life that aren’t simply answered as a result of of the place it lives.
Megamouth sharks are discovered from the ocean floor down to the bathypelagic zone which ranges from 1,000 to 4,000 meters (3,300 to 13,100 ft) deep. To put this into perspective, most navy submarines are restricted to 500 to 800 meters of water. Sunlight doesn’t attain this half of the ocean, making it the midnight zone. This doesn’t trouble the shark although as a result of it’s a filter feeder. Similar to the different giant filter feeder sharks (whale shark and basking shark), it eats zooplankton. These are microscopic organisms which are an important half of the base of the oceanic food chain. All the megamouth shark has to do is open its mouth and suck water in. Its mouth is designed to filter the zooplankton from the water, and as you’ll be able to think about with a identify like megamouth, it does it very effectively.
These zooplankton carry out every day migrations all through the water column. They keep deep during the day after which rise to the floor at evening earlier than repeating the course of the subsequent day. This is named diel vertical motion or DVM. They do that to feed on the phytoplankton at the floor which were growing and producing vitality whereas in the solar. This is an important course of as a result of this migration impacts many different animals, together with people who feed on zooplankton.
It’s believed that megamouth sharks show DVM as effectively, following their food source, however this hasn’t been confirmed. Scientists in a new research tagged and launched three megamouth sharks off the coast of Taiwan to grasp their every day and seasonal actions.
Daily Swimming
The tags confirmed that the megamouth sharks carried out diel vertical actions that matched their food. They would keep in the mesopelagic zone (200 – 1000 m) during the day, however come to the epipelagic zone (0 – 200 m) at evening. This conduct had been discovered in one other research that adopted a single particular person for two days off the coast of California back in 1997. However, there have been considerations that this was not consultant of the population. This research confirms this initial discovering is species vast.
Diel vertical actions will also be used for thermoregulation. Like most sharks, megamouths are cold blooded. They’re depending on exterior temperatures to control their physique temperature. The mesopelagic zone occurs to comprise the thermocline. This is the place heat floor water meets deep, cold water. The temperature adjustments the most alongside this space with a speedy decline the deeper you go. DVM could help megamouths regulate their physique temperature, staying in a explicit temperature vary that strikes up and down the water column as the solar rises and units.
Into the Deep
Megamouth sharks proceed to stay mysterious to us as a result of of how deep they reside. However, this research confirms the sharks carry out diel vertical actions to feed and/or thermoregulate. This is important to understanding how they use their habitat. We don’t know what the megamouth shark population appears to be like like so we now have no concept how many people there are. In this case, any new data that we will study them will help promote conservation efforts to guard this species.
I’m a current MSc graduate in marine biology from Bangor University, the place I studied population dynamics of elasmobranchs off the coast of Wales. My pursuits lie in ecological knowledge evaluation to grasp environmental processes and establish natural patterns. However, nothing beats being in the subject and interacting immediately with the marine life.
