For an unknown reason ... a noticeable increase in fish parasites and marine mammals

Mohammed Shaban

"If the fish gets damaged, search for the illness in the head." This is how the ancient Chinese saw disease and medicine. However, a new study published in the journal "Global Chang Biology" on March 19th showed that fish, squid, whales and dolphins infested parasites with 283 times more than they were in the 1970s.

This percentage is not a small amount, although it did not attract attention before, due to reasons such as the smallness of these parasitic organisms and the vast vast ocean, the researchers do not know the reason behind the growing growth of these parasites, and what they can cause in the long run.

The dangers of helminths
Parasitic nematodes - known as herring worms or Anisakis simplex - are hidden in raw seafood, which may cause symptoms similar to food poisoning if they are accidentally fed by humans. It also represents a major threat to fishing-dependent industries.

The same applies to other mammals that are not more fortunate than humans, as this parasite poses a great threat to whales and dolphins alike. Unlike humans, these parasites can remain stuck in the bodies of these mammals for years without being treated as humans and “sushi” chefs do when they clean their catch carefully.

This is not a worrisome matter for Aquarium and Fishery Scientist at Washington University Chelsea Wood. Also, fishing-dependent industries did not notice this increase in helminths. This indicates that the potential risk from ingestion may still be low. However, we cannot assume the same in the case of marine mammals.

"We have never believed that these parasites might be the reason for the decline in the activity of some marine mammalian groups. So I hope this study will encourage us to reconsider the intestinal parasites as a potential barrier to the growth of mammalian groups," Wood adds in her statement, reported by ScienceAlert. Endangered Navy. "

We do not know the effect of this growing parasite on marine mammals yet. If the numbers are correct, whales face a much greater risk of anisakis infection than they did half a century ago.

Increased injury to fish
The researchers had discovered a significant increase in the rate of infection of marine creatures with Anisakis worms over a period of 53 years, a period during which the present study analyzed its results. On average, researchers found that the incidence increased from less than one worm per 100 families until it reached more than one worm per single family.

The strange thing is that researchers were able to identify another type of similar parasite whose infection rate for marine organisms remained stable throughout that period. This parasite is known as "pseudoterranova", which affects fish, seals and sea lions.

"We were expecting the other way around, given the large seals and sea lions that have flourished in recent years, and the extent of the suffering of whales in comparison. Maybe the Anisakis life cycle - which is through fewer families - may have caused them to grow in this way. Or maybe it is due For whale agility compared to seals. "

Causes of increased infection rates
The main problem is that we do not know the line between what is normal and what is not. The increasing number of ocean worms may be a sign of a thriving ecosystem, or it may be a growing threat to marine creatures especially those threatened and endangered like Dolphin Hector.

Some recent studies provide the answer to this question. However, these studies came after the intervention of humans and changing the oceans in radical ways, which raises the question: Did the numbers of Anisakis increase as a result of the increase in human activity such as fishing and pollution, or climate change, or are they accompanying the marine mammals that are active on them?

We cannot say for now, Wood believes, that "some marine mammals thrive well, which leads to an increase in this parasite in some of the more vulnerable creatures in which the incidence is increasing greatly now. So we need to do more research."