Catfish and all manners of fish have a mucus and slimy outer coating on their bodies making them hard to hold onto. That mucus might be the key to the next antibiotic, say scientists who have worked with the skin of the scaleless, farmed African catfish.

Additional testing is necessary to prove the compound is safe and effective for use as future antibiotic, but it could be a potent new tool against antimicrobial-resistant bacteria such as extended-spectrum beta-lactamase (ESBL) producing E. coli.

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“The global public health threat due to antimicrobial resistance necessitates the search for safe and effective new antibacterial compounds,” says Hedmon Okella, a postdoctoral researcher at the University of California, Davis, and led the project.“In this case, fish-derived antimicrobial peptides present a promising source of potential leads.”

For the study, the researchers extracted several peptides (short chains of amino acids) from African catfish skin mucus and used machine learning algorithms to screen them for potential antibacterial activity.

They then chemically synthesized the most promising peptide, called NACAP-II, and tested its efficacy and safety on ESBL-E. coli and mammalian blood cells, respectively.

These tests showed that NACAP-II caused the bacteria to break open, or lyse, without appearing to harm the mammalian blood cells. “Preliminary findings indicate that this promising peptide candidate potentially disrupts the bacterial cell envelope to cause lysis at a very low concentration,” Okella said.

The place where the peptide was found — in the mucus on the skin of farmed African catfish — is not as unlikely as it may seem. As anyone who has tried to hold one can attest, fish are enveloped in a slippery layer of mucus. This mucus is known to protect the fish against infections by physically carrying germs off of the skin and by producing antimicrobial compounds such as the one Okella’s team isolated.

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Many existing medicines are based on compounds that were first found in nature, and scientists speculate that marine and aquatic organisms represent a particularly rich — though largely untapped — source of bioactive compounds. Ever pick up a snail and try to wash off the slime it leaves behind?

As a next step, the researchers plan to study the peptide’s effects in animal models and explore strategies to produce it inexpensively. “We are currently utilizing chemical synthesis to upscale the production of this peptide that we believe will one day be of use as drug candidate in the battle against antimicrobial resistance,” Okella said.

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The invasive blue crabs that made their way to Tunisia from the Indian Ocean via the Suez Canal were not welcome at first but since have turned into a new export. Another species of blue crab that originated in America is causing its share of problems for fisherman right now in Italy.

The Callinectes Sapidus, the blue crab, the Atlantic blue crab, or the Maryland blue crab is threatening Italy’s clam-farming and fishing industries. The Italian government has allocated about $3 million USD to fund the capture of as many blue crabs as possible.

As a past researcher on invasive species, working for CAB Biosciences in Switzerland, I am pretty certain that offering a bounty to catch these crabs will have no impact in the long run. The species, as invaders do, will only be balanced when a natural predator finds a way to keep them in check. Remember when the mayor of Hebron offered a $20 bounty for a truck of dead dogs?

At the same time, the blue crab is the fifth most popular crab in the world market. It is especially sought out in the Asian, United States and Australian markets where it is featured on the menus of many restaurants.

According to Nature, the blue crab in Italy was first observed in the Mediterranean Sea in 1949, where it was probably transported in the ballast waters of transoceanic ships.

“The colonisation took some time, it is a slow process,” says Gianluca Sarà, marine ecologist at the University of Palermo. Before invading the Po River Delta, Atlantic blue crabs have been spotted in other locations in Italy. Established populations were first detected in 2014 in the lagoon of Lesina and Varano, in Apulia.

Climate change is suspected to be one of the reasons the blue crab was able to slide into Italy from the Adriatic Sea. Researchers are now looking on how their colonisation will impact other aquatic sea life and shores.

Invasive species like the Portunus segnis from the Indian Ocean or Callinectes Sapidus, the Atlantic blue crab, lived in ecosystems that that developed over thousands, maybe millions of years. The Suez Canal changed this separation between seas fast and is the reason why the Mediterranean is over-run with jellyfish every summer, making it impossible to swim in places like Israel and Lebanon for fear of getting stung during the hottest times of the year.

Two blue crabs invade. Let’s get those crabs straight

Portunus segnis, is the scientific name for the African blue swimming crab. It is a crustacean, and a swimming crab belonging to the family Portunidae. It is native to the western Indian Ocean, but invaded the Mediterranean Sea via the Suez Canal in Egypt. In 2015 it invaded the Gulf of Gabes, in southern Tunisia. Now the country has dozens of crab-processing plants. “At first fishers wanted this species to disappear, but now they are asking the authorities for regulations to protect it,” says one fisherman.

Another invasive blue crab, the one invading Italy currently is Callinectes sapidus, the Atlantic blue crab, or regionally known in the US as the Maryland blue crab. It is a species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico, and it is now introduced internationally. It is also known as the Chesapeake blue crab.

Global shipping industry to blame for invaders

According to The Revelator, “global shipping is moving invasive species around the world.”

They report that “in July 2021 federal agents in New Orleans abruptly ordered the 600-foot cargo ship Pan Jasmine to leave US waters. The ship, which had sailed from India, was preparing to offload goods when inspectors noticed fresh sawdust on the cargo deck and discovered non-native beetles and ants boring into wooden packaging materials. The unwelcome insects included an Asian longhorn beetle, a species that was introduced into New York 25 years ago, where it has killed thousands of trees and cost $500 million in control efforts.

“The crew of beetles aboard the Pan Jasmine is not an isolated incident. That same month bee experts north of Seattle were scouring forest edges for Asian giant hornet nests. These new arrivals, famously known as “murder hornets,” first turned up in the Pacific Northwest in 2019, also likely via cargo ship. The two-inch hornets threaten crops, bee farms and wild plants by preying on native bees. Officials discovered and destroyed three nests.

“And this past autumn Pennsylvania officials urged residents to be on the lookout for spotted lanternflies, handsome, broad-winged natives of Asia discovered in 2014 and now present in at least nine eastern states. Believed to have arrived with a shipment of stone from China, the lanternfly voraciously consumes plants and foliage, threatening everything from oak trees to vineyards.”

Can world governments agree on necessary preventative measures?

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Although considered largely unsuccessful at preventing the nearly inevitable extinction of the Atlantic Bluefin Tuna at last week’s International Commission for the Conservation of Atlantic Tunas (ICCAT) gathering in Istanbul, Susan Lieberman of the PEW environment group told Jennifer Hattam with Treehugger, one of the contributors to our recently launched blogging guide Barefoot Bloggers, that certain progress was made.

In particular, the group was able to persuade ICCAT to adopt a new electronic monitoring device that will make it a lot harder for fishermen to fudge catch numbers. If unsuccessful, if Bluefin Tuna fishing in the Mediterranean is not better managed, another member of the PEW delegation Lee Crocket told the Washington Post that the population will have less than a 24% chance of reviving in the next decade.

Illegal fishing in the Mediterranean

One of the greatest challenges to monitoring Bluefin Tuna catch in the Mediterranean is lack of enforcement. This is especially true in the context of the political problems sweeping through the region. Earlier this year – before former Libyan President Muammar Gaddafi was hunted down and killed -fishing vessels were found to be fishing illegally in the northern Mediterranean. But nobody could prove who they belonged to, though it is suspected that Italy and Malta were involved.

The new electronic monitoring device will mitigate some of these problems.

Lee Crocket told WP:

ICCAT must adopt an electronic-catch documentation system, because the current paper-based system is full of holes and allows unreported and illegally caught fish to enter the market,” said Lee Crockett, bluefin tuna expert of the Pew Environment Group. He said an electronic system would close loopholes by adding real-time monitoring, facilitating enforcement, and providing a more accurate count of the amount of bluefin tuna caught each year.

Last year, both publications reported that 140 percent more meat was sold than what is either legal or reported. This is largely possible because the fish are measured in terms of weight rather than numbers before they are sent to fattening farms in Turkey and other Mediterranean countries, where they are fed fatty food that bulks them up prior to trade with Japan.

The problem of bycatch

The new electronic monitoring devices will not be able to save sharks and other marine by-catch such as turtles that are caught on wire fishing line leaders.

Bluefin Tuna are predators that play a critical role in marine ecosystems, but they also generate a lot of income, so finding sustainable solutions that work for fishermen, the Japanese, and the species itself, has thus far eluded stakeholders. The new electronic monitoring device still requires self-reporting, so it’s definitely not foolproof, but it could be a good step in the right direction.

:: Treehugger, Washington Post

image via Greenpeace

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Bottom trawlers were forced to set sail after Oman effected its ban on this destructive “fishing” practice. A small Gulf country that borders the United Arab Emirates, Oman is renowned for its incredible coral reefs and marine diversity. But 16 large factory fishing boats operating off shore had jeopardized the Sultanate’s marine health and put many fishermen out of work.

First put in place by the Ministry of Agriculture and Fisheries in May 2009, the ban stipulated that licensed bottom trawlers would have to pack up their nets and leave the Sultanate’s waters within two years. And now, their time is up. Oman is the first Gulf country to officially ban bottom trawling.

Bulldozing the sea floor

Bottom trawlers drag massive nets with mouths sometimes as large as a rugby field across the sea floor or sea mount. These nets are kept in place with “doors” that can weigh up to five tons.

Used to capture bottom-dwelling fish, the nets are like bulldozers that raze everything in sight, including non-edible marine creatures and sensitive coral reefs. Areas destroyed by commercial trawling won’t recover for centuries, according to the Gulf Coast Preservation Society in the United States.

Local fishermen express huge relief

The Times of Oman reports that local fishermen are deeply relieved that the trawlers are gone. One man told the paper that he would spend 18 hours at sea and still have to buy his fish at the market. Bottom trawlers sucked up all of the catch, and forced many subsistence fishermen to raise their prices to unsustainable levels.

Local Omanis are in shock. In the Middle East, bans such as those on shark finning and owning endangered wildlife are often ignored. But the Sultanate contacted trawlers to remind them that their two year grace period would soon end, and on Wednesday followed through on banning them from Oman’s territorial waters.

“I am quite sure that fish prices will come down now as our boats will be full of different varieties of fish, like it used to once,” a local fisherman, Haroon Al H’sani, told the Times.

Oman leads the green way

Oman’s environmental protection leadership can be traced back to March 1979 when the the Council for Conservation of the Environment and Prevention of Pollution (CCEPP) was first established. Then in 1996, the Sultanate created their National Conservation Strategy.

Since then, earth trends reports that 32 Marine and Littoral Protected Areas have been established.

When the Gulf waters begin to teem with life and local fishermen can make a decent living again, hopefully Oman’s leadership will rub off on other Gulf countries. This is a huge victory for our oceans. And a milestone for the Middle East.

:: The Times of Oman

More on commercial and illegal fishing practices in the Gulf:

Reporter’s Notebook: Tasteless Dry Shark Fin For Sale

Working with Local Fisherman to Tackle Shark Finning

Hope Amidst Dubai’s Marine Destruction

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