Hexbyte Glen Cove Chemical pollutants disrupt reproduction in anemonefish, study finds

Hexbyte Glen Cove

The sex of anemonefish is dependent on environmental cues, allowing researchers to study how environmental chemicals can affect their reproduction. Credit: Ed Clint

Ocean pollution is unfortunately becoming more commonplace, raising concerns over the effect of chemicals that are leaching into the water. In a new study, researchers have discovered how these chemicals can affect the reproduction in common anemonefish Amphiprion ocellaris.

Endocrine disrupting chemicals—which interfere with how the body’s hormones work—can obstruct normal reproduction in animals. Bisphenol A and 17a-Ethinylestradiol (EE2) are two common chemicals of this nature. BPA is an endocrine disruptor and is found in a lot of different plastics like water bottles and EE2, commonly found in , enters into the ocean from and wastewaters of manufacturing plants and hospitals.

“In Indonesia, for example, there are beautiful coral reefs found below a lot of garbage, so anything that enters the water is affecting the ,” said Jose Gonzalez, a former undergraduate researcher in the Rhodes group.

“There have been previous studies that have established that these pollutants tend to feminize animals like , rats, mice, and even humans,” said Justin Rhodes (GNDP), a professor of psychology. “However, no one has studied their effects on a fish whose sex is totally determined by the environment.”

A. ocellaris live in with one alpha female, one beta male, and lower ranking non-reproductive males. Their sex is not genetically programmed and, instead, is dependent on environmental cues: A male transforms into a female if the female is removed from the group or if males are paired together.

“We looked at these fish specifically because they can transition from male to female helping us understand how BPA and EE2 can affect reproduction,” said Sarah Craig, an undergraduate research assistant in the Rhodes group.

The researchers paired sexually immature, male fish and fed them twice daily with normal food, food containing BPA, or EE2. There were 9 pairs of fish per group and they were monitored for six months. The amount of BPA and EE2 were determined based on the environmental concentrations of these chemicals.

“Since these fish are able to change their sex, we looked at different indicators such as behavior, gene expression in the brain, and ,” said Abigail Histed, an undergraduate research assistant in the Rhodes group. “Interestingly, other than behavior, we found a feminizing effect in all the other categories.”

The researchers found that fish that were fed BPA had no testicular tissue, lower androgen levels, just like female fish, and increased expression of genes in the brain that are responsible for feminization. Surprisingly, although females tend to be more aggressive, BPA decreased aggression in these fish. In contrast, the effects of EE2 were similar, but less pronounced.

“In nature, the females are very aggressive and do not tolerate the presence of other females,” Rhodes said. “We discovered that although BPA is feminizing the gonads, the fish are not that aggressive and can live with each other. These results suggest that the feminization in the brain occurs independently of gonadal hormones.”

It is still unclear how BPA is exerting its effects. In other studies BPA was thought to bind to estrogen receptors. However, since EE2 is an estrogen mimic and had subtle effects, the researchers believe that BPA has other additional effects. “BPA could be affecting other hormone receptors or interfering with androgen signaling. It could be a mix of different effects and we don’t know yet,” Rhodes said.

The implications of the findings, however, are clear. “These fish can only change their sex from male to female. If BPA is turning them female in the wild, they can’t go back to being a male and that can influence their population numbers,” Gonzalez said.

The researchers are interested in investigating the effects of EE2 further. Specifically, they would like to use higher concentrations of EE2 because they are concerned that the administered levels were not high enough. They would also like to follow the fate of these fish for longer since the fish normally take more than six months to mature completely.

“A longer time frame would be better to compare the degrees of feminization with BPA compared to natural feminization. Maybe they do eventually fight and kill each other and it’s something we missed with a shorter time frame,” Rhodes said.

The study “Impact of bisphenol-A and synthetic estradiol on brain, behavior, gonads and sex hormones in a sexually labile coral reef fish” was published in Hormones and Behavior.



More information:
Jose A. Gonzalez et al, Impact of bisphenol-A and synthetic estradiol on brain, behavior, gonads and sex hormones in a sexually labile coral reef fish, Hormones and Behavior (2021). DOI: 10.1016/j.yhbeh.2021.105043

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Chemical pollutants disrupt reproduction in anemonefish, study finds (2021, December 4)
retrieved 4 December 2021

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Hexbyte Glen Cove Sri Lanka ends farm chemical ban as organic drive fails

Hexbyte Glen Cove

Sri Lanka has abandoned its quest to become the world’s first completely organic farming nation.

Sri Lanka abandoned its quest to become the world’s first completely organic farming nation on Sunday, announcing it would immediately lift an import ban on pesticides and other agricultural inputs.

The island country has been in the grips of a severe economic crisis, with a lack of foreign exchange triggering shortages of food, and other essential goods.

Authorities had already walked back restrictions on fertiliser imports last month for tea, the country’s main export earner.

But ahead of planned farmer protests in the capital, Sri Lanka’s agricultural ministry said it would end a broader ban on all agrochemicals including herbicides and pesticides.

“We will now allow chemical inputs that are urgently needed,” ministry secretary Udith Jayasinghe told the private News First TV network.

“Considering the need to ensure , we have taken this decision.”

Vast tracts of farmland were abandoned after the import ban, first introduced in May.

Shortages have worsened in the past week, with prices for rice, vegetables and other market staples having doubled across Sri Lanka.

Supermarkets have also rationed rice sales, allowing only five kilograms (11 pounds) per customer.

Farmers’ organisations had planned to march on the national parliament in Colombo on Friday to demand the import of essential chemicals to protect their crops.

President Gotabaya Rajapaksa had justified the import ban by saying he wanted to make Sri Lankan farming 100 percent organic.

The policy was introduced after a massive hit to the cash-strapped island’s economy in the wake of the Covid-19 pandemic, with tourism earnings and foreign worker remittances drastically falling.

Authorities attempted to save foreign exchange by last year banning a host of imported goods, including some food and spices.

Sri Lanka also shut its only oil refinery last month after running out of dollars to crude.



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Sri Lanka ends farm chemical ban as organic drive fails (2021, November 21)
retrieved 22 November 2021
from https://phys.org/news/2021-11-sri-lanka-farm-chemical.html

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