Skin Cancer Found in Wild Fish for First Time

Fish are getting skin cancer. For the first time ever, scientists are finding melanoma is not just increasing in people. It is also affecting wild fish.

An international team of researchers examined a commercially-important marine fish, the coral trout (Plectropomus leopardus). †In two sites in the Great Barrier Reef Marine Park, they discovered 15 percent of the trout bore lesions like the melanoma lesions in laboratory experiments with Xiphophorus. (Those playfish or swordfish have long been used in cancer research.) Some of the coral trout had only small lesions. Others were nearly black with them.

Prior to this study, scientists assumed only the hybrid crosses of Xiphophorus bred in captivity could contract melanoma. Their wild relatives were not susceptible, even after being exposed to high doses of physical and chemical carcinogens.

The lesions on the Great Barrier Reef fish had not spread beyond the skin, but lead author Dr. Michael Sweet, University of Newcastle, cautions that does not mean melanoma is not harmful to fish. He said:

Once the cancer spreads further you would expect the fish to become quite sick, becoming less active and possibly feeding less, hence less likely to be caught. This suggests the actual percentage affected by the cancer is likely to be higher than observed in this study.

Dr. Michelle Heupel, Australian Institute of Marine Science, suggests the fish may have interbred, with hybridization giving them a genetic predisposition to melanoma. Their immune systems may also be compromised because of their living in an area that is near their temperature threshhold. She said:

It may just be that theyíre living close to the edge there and this genetic composition makes them a little more susceptible. And thatís combined with UV exposure in the region. I really think itís the combination of all those factors working together rather than one thing independently.

The research team cites an urgent need for more studies to determine what factors are causing the melanoma, how many fish are being killed by it, and how widespread the syndrome actually is. The answers will have important implications, not just for coral trout but also for commercial and recreational fisheries.

The research can be found on PLOSone: M. Sweet, et al. (2012) Evidence of Melanoma in Wild Marine Fish Populations.

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Photo 1 by Richard Ling, via Wikimedia Commons; Photo 2 courtesy of PLOSone


Loesje vB
Loesje Najoan5 years ago

This is very bad news!!! I guest we are all responsible of our planet, the oceans, water and poisoning wild fish.

Prosonjit S.
Prosonjit S.5 years ago

II have a scar on my right cheek from a large mole removed when I was three years old. It was itchy and the bumpy red part bled when scratched. Turns out it was Basal Cell Carcinoma.

Beth Wilkerson
Beth Wilkerson5 years ago

We are changing the Earth and it's inhabitants.

Peggy Dirsa
Maureen Dia5 years ago

Radiation poisoning and BP Gulf oil spill "cleaning agents" are causing this and it's not all that NEW, they just can't hide it as much from the public anymore.

Teresa Wlosowicz
Teresa W5 years ago

very sad

Mark Donners
Mark Donner5 years ago

Obama is not an environmental president..just a liar

Dianne D.
Dianne D5 years ago

This may be the canary in the mine. If we don't clean up our oceans and waterways, humans are domed also.

Alex H.
Alex H5 years ago

This is proof that melanoma is a toxic contamination disease which comes from the inside of the body! Our waters and oceans are becoming chemical cesspools after sixty years of having the most toxic substances known,including radioactive waste dumped into them!What hope has marine life got when the only environment they can survive in,is like that! I believe that people need to stop eating seafood if they don't want to be poisoned!

Lisa D.
Lisa D5 years ago

absolutely shocking and disturbing news.. although we cant really say it is 100% suprising.. its only a matter of time for these things to happen when we abuse the world around us at the rate and speed we are at

Edgar Zuim
Edgar Zuim5 years ago