Is it really necessary to clean barnacles from whales and turtles?

Recently, there have been many videos of people removing barnacles from marine animals online - people using small spatulas to remove barnacles from turtles, or removing barnacles from whales' backs during whale watching. The videos usually explain that this behavior can help poor turtles, or that whales actively seek help from humans.

However, is it really necessary to debarnacle animals?

There are densely packed barnacles on the turtle's shell. Be careful of slippery water｜Screenshot from a video on the Internet

Hitchhiker

Let’s first talk about what these barnacles are and why they grow on whales and turtles.

Barnacles are filter-feeding organisms that mostly grow fixedly in shallow waters and feed on plankton and other tiny organisms by filtering the water.

Barnacles are crustaceans, belonging to the same subphylum as crabs and shrimps. They are neither shellfish nor conchs, nor are they corals. © Aleria Jensen/Wikimedia Commons

Barnacles are not born with hard shells, but begin their lives as free-swimming, planktonic larvae that settle on a suitable substrate and develop into sessile adults.

Since adults cannot move, they need to find a hard, moderately rough substrate with gentle currents nearby to settle on during the larval stage. For some species of barnacles, whales and turtles are the best choices. Of course, reefs on the sea, ship hulls in the sea, and wooden piles are also good places for barnacles.

The head, back and fins usually have stable water flow, which is suitable for barnacles to settle down. | Tuchong Creative

When whales swim in warm, shallow waters during the breeding season, larvae of the Coronulidae species pick up on chemical signals released by the whales and swim to the whales, extending muscular stalks that grip the whales' skin and cling to them with mucus .

The settled barnacle larvae gradually transform into immobile adults, grow calcium shells , and ride the wave for life. When whales and turtles swim, barnacles enjoy the food in the water. It is really enviable that they can live without worries about food and clothing without running around, and spend every day in adventure.

When barnacles hunt, they push out their limbs and pull the food into their shells. | Jim Auzins

Are barnacles parasites?

It sounds like these barnacles that "live on other people's homes" are very much like parasites!

It is true that some barnacles live a parasitic life. Some of them feed exclusively on shark meat, and some feed exclusively on crab meat. However, those barnacles that like to ride on whales and sea turtles eat plankton in the water flow and do not threaten whales and sea turtles, so they are not parasites . Barnacles have a symbiotic relationship with whales and sea turtles.

Barnacles on turtle shells | TuChong Creative

Barnacles may make whales and turtles feel itchy, but they will not cause direct pain or harm. A humpback whale can carry about 450 kilograms of barnacles , which sounds heavy; however, compared with the humpback whale's weight of 25 to 30 tons, the extra weight of these passengers is like us humans wearing clothes, and the impact on normal life is minimal .

Gray whales and humpback whales, which swim at a relatively slow speed (about 10km/h), are the most common "hitchhikers" among whales｜TuChong Creative

Moreover, this symbiotic relationship may be mutually beneficial . Barnacles are protected by large marine animals such as whales, which can greatly reduce the probability of being preyed on by crabs and starfish; barnacles also become armor for whales, making it more difficult for predators to catch whales. After all, the hard shells of barnacles should be more irritating to the teeth.

Why are killer whales, the top predators, so smooth and free of barnacles? Unfortunately, killer whales often frequent cold waters, and they swim too fast (about 56 km/h). Fast, cold water is not an ideal habitat for barnacles .

Barnacles are an indicator of health

Barnacles don't make turtles and whales sick, but they are an important health indicator for these animals, especially turtles.

If a turtle is sick or injured, it will become slow. Barnacles like gentle currents, so a slow-swimming turtle may attract more barnacle larvae to take root . Too many barnacles may increase the turtle's swimming resistance, and barnacles on the face may affect vision and eating, which is even worse for the already weak turtle.

This loggerhead sea turtle's head is covered in barnacles | Dubai Turtle Rehabilitation Project / Facebook

Therefore, if a sea turtle is covered with barnacles and looks very dull and lazy, it can probably be judged that it is sick. Almost all sea turtle species are endangered, and many marine animal protection organizations monitor and judge the health status of sea turtles based on the amount of barnacles . If they encounter a sick or injured sea turtle, they will first help the turtle clean the barnacles, and then treat and release it.

Cleaning barnacles requires scientific and professional operations. Turtles can live in fresh water for several days, but barnacles cannot survive in fresh water environments . Therefore, rescuers usually soak turtles in fresh water for 2 to 3 days, and then use a blade of moderate thickness to shovel out the barnacles after they die, minimizing the damage to the turtles .

Rescuers use tools to remove barnacles | Olive Ridley Project

In addition, baby turtles are prone to having too many barnacles attached to their bodies.

As a reptile, sea turtles are cold-blooded and cannot regulate their body temperature . When winter comes and the weather turns cold, baby turtles become drowsy and slow in their movements, which creates a good opportunity for barnacles to attach. Every winter on the beaches of Dubai, baby hawksbill turtles covered with barnacles are often stranded. The Dubai Turtle Conservation Organization will remove the barnacles from these stranded baby turtles to reduce their stress and help them survive the winter .

A stranded baby turtle covered in barnacles | Dubai Turtle Rehabilitation Project / Facebook

It is not recommended that ordinary people blindly clean up barnacles

Many of the barnacle cleaning videos on the Internet show unprofessional operations.

In some videos of "helping" turtles, people skip the "fresh water soaking" step and directly remove barnacles from turtles that have just been scooped out of the sea. This is not only difficult to operate, but also easy to hurt the turtle. Moreover, if you only remove the thick barnacles without checking the cause of the turtle's weakness, it is only a temporary solution and cannot really help the turtle .

In some videos, the things that can be pulled out with a simple tug are actually not barnacles at all, but whale lice or leeches . Some people even glue barnacles to the shells of freshwater turtles with glue to make it look like they are removing barnacles from turtles, which is even more extreme.

Barnacles are so strong that you can't just pick them up with your bare hands | Screenshot of a video from the Internet

If you find a turtle that doesn't look healthy, you should contact the local animal protection agency and have professionals take it in and treat it. The strong stickiness of barnacles makes it very difficult to remove them. If ordinary people do not operate properly, it is easy to hurt the animals . Therefore, it is really not recommended that ordinary people blindly remove barnacles from animals, and it is even more undesirable to take videos to mislead everyone.

A turtle injured by violent barnacle removal | Dubai Turtle Rehabilitation Project / Facebook

As for the statement that "healthy turtles and whales need human help to remove barnacles", a little thought will reveal the loopholes in it. In the past, whales and turtles have been living well without human "help"; and even if humans help them remove barnacles, they have been living in the ocean for a long time, and new barnacles will still attach and grow !

In fact, animals have their own ways . Humpback whales have been photographed rolling on the seabed, scrubbing, or scratching with the hull of a ship to remove keratin and barnacles; and when sea turtles mate, the partners rub their bodies against each other, and some barnacles will fall off them.

Humpback whale bathing scene | Olaf Meyneck

Animals are very resilient and, in most cases, can take care of themselves without human intervention.

References

[1] https://turtlespet.com/do-barnacles-hurt-seaturtles/#google_vignette

[2] https://oceanfauna.com/barnacles-on-whales-do-barnacles-hurt-whales/

[3] https://home.org/do-barnacles-hurt-whales/

[4] https://oliveridleyproject.org/?s=barnacle

[5] http://courses.washington.edu/mareco07/students/nina/barnacleshome.html

[6] Zardus, JD (2021). A global synthesis of the correspondence between epizoic barnacles and their sea turtle hosts. Integrative Organismal Biology, 3(1), obab002-obab002. https://doi.org/10.1093/iob/obab002

Author: Bowl

Editor: Mai Mai

This article comes from GuokrNature (ID: GuokrNature)

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