Quantcast
Environmental News for a Healthier Planet and Life

Female Fish Eggs Found Inside of Male Fish Testicles

Science
Female Fish Eggs Found Inside of Male Fish Testicles

A study published by the U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service found large-scale evidence of intersex in smallmouth and largemouth bass in the Northeast U.S., an indicator of endocrine disruption. The study, published in the journal Ecotoxicology and Environmental Safety, looks at 19 U.S. National Wildlife Refuges and is the first reconnaissance survey of this scope. The study found that the prevalence of testicular oocytes across all samples was 85 percent and 27 percent for male small- and largemouth bass, respectively.

Intersex occurs when one sex develops characteristics of the opposite sex. In the case of this study, researchers found testicular oocytes—female eggs found inside male testicles—in male smallmouth and largemouth bass. The study explains: “The presence of oocytes in the testes of male gonochoristic fish has been used as an indicator of estrogenic exposure.”

The source of the estrogen is hard to pinpoint, but pesticides are often cited as a cause given that they widely pollute waterways that fish populate. Those chemicals have properties that disrupt the endocrine system and affect the reproductive system, causing development issues such as testicular oocytes. According to USGS, “Intersex is a global issue, as wild-caught fish affected by endocrine-disrupting chemicals have been found in locations across the world.”

According to the USGS press release for the study, “Estrogenic endocrine-disrupting chemicals are derived from a variety of sources, from natural estrogens to synthetic pharmaceuticals and agrochemicals that enter the waterways. Examples include some types of birth control pills, natural sex hormones in livestock manures, herbicides and pesticides.”

While the study did not look for the sources of endocrine disruption, it did paint a picture of how widespread this abnormality really is, encouraging management actions to combat runoff. “It is not clear what the specific cause of intersex is in these fish,” Luke Iwanowicz, a USGS research biologist and lead author of the paper, said, in their press release. “This study was designed to identify locations that may warrant further investigation. Chemical analyses of fish or water samples at collection sites were not conducted, so we cannot attribute the observation of intersex to specific, known estrogenic endocrine-disrupting chemicals.”

Last summer, research by the USGS showed a strong correlation between the occurrence of intersex characteristics on fish, which have been found in the Chesapeake Bay region and areas of high agricultural use in Pennsylvania. In addition, a recent report by the Pennsylvania Department of Environmental Protection (DEP) found rare malignant tumors on smallmouth bass in the Susquehanna River, a river that flows through the northeast from upstate New York to the Chesapeake Bay. The Susquehanna River is a major source of agricultural runoff containing phosphorous, nitrogen and sediment pollutants, as well as natural animal hormones in manure. Pennsylvania DEP officials are looking to in-depth studies to identify the sources of the endocrine-disrupting compounds and herbicides likely contributing to the tumors.

This is a step that USGS would like to see taken as well. The study states, “A comprehensive re-evaluation that includes chemical analysis and seasonal snapshots of both sites is necessary to identify the likely cause(s) of elevated plasma vitellogenin in these male smallmouth bass.”

In addition to the Pennsylvania DEP study, other scientists are examining fish as a means of gauging water quality and chemical exposure. In 2008, USGS identified ten contaminants, including atrazine, chlorpyrifos and endosulfan, responsible for intersex fish in the Potomac River. Atrazine, one of the most commonly used herbicides in the world, has been shown to affect reproduction of fish at concentrations below U.S. Environmental Protection Agency’s water-quality guidelines. A November study found that commonly-used pesticides can persist in and impact the species of a waterway long after the chemicals are detectable or monitored by regulators.

YOU MIGHT ALSO LIKE

Groundbreaking Study Says Asian Carp Could Make Up One-Third of Lake Erie Biomass

Oppose Welfare Ranching, Not Wolves

Beloved Orca Found Dead Due to Entanglement in Fishing Gear

How the Wise Use Movement Is Tied to the #OregonStandoff

Former U.S. Sec. of Energy Ernest Moniz listens during the National Clean Energy Summit 9.0 on October 13, 2017 in Las Vegas, Nevada. Isaac Brekken / Getty Images for National Clean Energy Summit

By Jake Johnson

Amid reports that oil industry-friendly former Energy Secretary Ernest Moniz remains under consideration to return to his old post in the incoming Biden administration, a diverse coalition of environmental groups is mobilizing for an "all-out push" to keep Moniz away from the White House and demand a cabinet willing to boldly confront the corporations responsible for the climate emergency.

Read More Show Less

EcoWatch Daily Newsletter

Climate change can evoke intense feelings, but a conversational approach can help. Reed Kaestner / Getty Images

Anger, anxiety, overwhelm … climate change can evoke intense feelings.

"It's easy to feel dwarfed in the context of such a global systemic issue," says psychologist Renée Lertzman.

She says that when people experience these feelings, they often shut down and push information away. So to encourage climate action, she advises not bombarding people with frightening facts.

"When we lead with information, we are actually unwittingly walking right into a situation that is set up to undermine our efforts," she says.

She says if you want to engage people on the topic, take a compassionate approach. Ask people what they know and want to learn. Then have a conversation.

This conversational approach may seem at odds with the urgency of the issue, but Lertzman says it can get results faster.

"When we take a compassion-based approach, we are actively disarming defenses so that people are actually more willing and able to respond and engage quicker," she says. "And we don't have time right now to mess around, and so I do actually come to this topic with a sense of urgency… We do not have time to not take this approach."

Reporting credit: ChavoBart Digital Media
Reposted with permission from Yale Climate Connections.

Trending

A rare North Atlantic right whale is seen off Cape Cod Bay on April 14, 2019 near Provincetown, Massachusetts. Don Emmert / AFP / Getty Images

An extremely rare North Atlantic right whale calf was found dead off the North Carolina coast on Friday.

Read More Show Less
Sprinklers irrigate a field of onions near a Castilian village in Spain. According to a new study, the average farm size in the EU has almost doubled since the 1960s. miguelangelortega / Moment / Getty Images

By Andrea Germanos

A new report released Tuesday details the "shocking" state of global land equality, saying the problem is worse than thought, rising, and "cannot be ignored."

Read More Show Less
Members of the San Carlos Apache Nation protest to protect parts of Oak Flat from a copper mining company on July 22, 2015 in Washington, DC. Brendan Smialowski / AFP / Getty Images

In yet another attack on the environment before leaving office, the Trump administration is seeking to transfer ownership of San Carlos Apache holy ground in Oak Flat, Arizona, to a copper mining company.

Read More Show Less