The discovery that shrimp living in polluted waters produce 70% less sperm is a warning to all species, including humans, according to scientists.
Researchers from the University of Portsmouth also found that there were six times less of the sea creatures living in the study area on the south coast of England, compared with cleaner waters.
Professor Alex Ford, professor of biology, said the study, published in Aquatic Toxicology, mirrors similar findings in other animals, including humans, and should be treated like the “canary in the mine”.
He said: “We normally study the effect of chemicals on species after the water has been treated. The shrimp that we have tested are often in untreated water.
“The study site suffers from storm water surges, which is likely to become more common with climate change.
“This means that the creatures could be exposed to lots of different contaminants via sewage, historical landfills and legacy chemicals such as those in antifouling paints.
“There is a direct relationship between the incidence of high rainfall events and in the levels of untreated sewage.”
Explaining the possible implications for humans, he added: “It is thought that some male fertility problems are related to pollution.
“It may not be the same pollutants, but it is all chemicals that are being released into the environment. It is not being stopped and, more importantly, the effects are not being properly monitored or understood.
“Researchers have been looking at worldwide declines in sperm counts of humans over the past 50 years.
“Research has shown that in some countries, a boy born today will have half the sperm count of his grandfather and there are fears boys are getting critically close to being infertile.”
Prof Ford said that other marine creatures were also suffering and added: “We know that pollutants are affecting male fertility levels of all species.
“Killer whales around our coasts are contaminated with so many pollutants that some can’t reproduce.
“Recent studies have also suggested that harbour porpoises contaminated with highly toxic industrial compounds, known as polychlorinated biphenyls (PCBs), have smaller testes.”
The research carried out on shrimp numbers in Langstone Harbour, next to Portsmouth, have also shown that females are producing less eggs which the scientists believe could lead to a population collapse in the area with a knock-on effect on the food chain.