A 22-pound, 5-ounce largemouth bass (picture) has been caught by Manabu Kurita, a pro staffer representing Deps Tackle Co. in Japan. This breaks George Perry’s old record from June 2, 1932. The bass caught by Perry in Montgomery Lake, Georgia 77 years ago weighed 22-pound, 4-ounce – just a tad less than the new Japanese record bass. Kurita’s bass was 29.4 inches long (no girth measurements have been released). It was reportedly weighed on a certified scale.

Kurita caught his 22-pound, 5-ounce bass in Lake Biwa (琵琶湖, Biwa-ko), in Japan’s Shiga Prefecture. Formed by tectonic shifts almost 4 million years ago, Lake Biwa is one of the world’s twenty oldest lakes and home to a very rich ecosystem that includes 58 described endemic species. It is the largest freshwater lake in the country and covers nearly 259 square miles.

After holding the International Game Fish Association (IGFA) all-tackle world record for 77 year, it seems as if Perry might have to if not step down then at least share the first place with his fellow Japanese angler. IGFA rules stipulate that a bass must weigh two ounces more than the current record holder to break the record, so Kurita’s fish will only tie it.

“It will tie [Perry’s record] if that’s the weight,” says Jason Schratwieser, record andconservation director for the game fish association. “For record fish weighing less than 25 pounds, the replacement record must weigh at least 2 ounces more than the existing record.”

In 2006, Mac Weakley caught a 25-pound, 1-ounce bass in Lake

Dixon, California, but he didn’t pursue the record since he accidently foul-hooked the fish, i.e. he didn’t hook the fish in the mouth.

Scientists from the U.S. Geological Survey (USGS) have revealed that largemouth bass injected with oestrogen produces less hepcidin than normally. Hepcidin is an important iron-regulating hormone in fish, amphibians and mammals, and researchers also suspect that hepcidin may act as an antimicrobial peptide. In vertebrate animals, antimicrobial peptides are the body’s first line of defence against unwelcome bacteria and some fungi and viruses, so if there’re right, a lowered amount of these compounds is certainly not good news.

“Our research suggests that estrogen-mimicking compounds may make fish more susceptible to disease by blocking production of hepcidin and other immune-related proteins that help protect fish against disease-causing bacteria,” says lead author Dr. Laura Robertson.

You can find more info in the study “Identification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)” by Laura Robertson, Luke Iwanowicz and Jamie Marie Marranca in the latest issue of the journal Fish & Shellfish Immunology. It is the first published study demonstrating control of hepcidin by estrogen in any animal.

The inclination to end up stuck on a hook seems to be a heritable trait in bass, according to a study published in a recent issue of the Transactions of the American Fisheries Society.

The study, which was carried out by researchers DP Philipp, SJ Cooke, JE Claussen, JB Koppelman, CD Suski, and DP Burkett, focused on Ridge Lake, an Illinois lake where catch-and-release fishing has been enforced and strictly regulated for decades. Each caught fish has been measured, tagged and then released back into the wild.

Picture by: Clinton & Charles Robertson from Del Rio, Texas & San Marcos, TX, USA

David Philipp and coauthors commenced their study in 1977, checking the prevalence of Largemouth bass (Micropterus salmoides) on the hooks of fishermen. After four years, the experimental lake was drained and 1,785 fish were collected. When checking the tags, Philipp and his team found that roughly 15 percent of the Largemouth bass population consisted of specimens that had never been caught. They also found out that certain other bass specimens had been caught over and over again.

To take the study one step further, the research team collected never caught bass specimens (so called Low Vulnerability, LV, specimens) and raised a line of LV offspring in separate brood ponds. Likewise, the team collected bass specimens caught at least four times (High Vulnerability, HV, specimens) and placed them in their own brooding ponds to create a HV line.

The first generation (F1) offspring from both lines where then marked and placed together in the same pond. During the summer season, anglers where allowed to visit the pond and practise catch-and-release, and records where kept of the number of times each fish was caught.

As the summer came to an end, HV fish caught three or more times where used to create a new line of HV offspring, while LV fish caught no more than once became the parents of a new LV line.

The second generation (F2) offspring went through the same procedure as their parents; they were market, released into the same pond, and subjected to anglers throughout the summer. In fall, scientists gathered the fish that had been caught at least three times or no more than once and placed them in separate ponds to create a third generation (F3) HV and LV fish.

A following series of controlled fishing experiments eventually showed that the vulnerability to angling of the HV line was greater than that of the LV line, and that the differences observed between the two lines increased across later generations.

If this is true not only for bass but for other fish species as well, heavy hook-and-line angling pressure in lakes and rivers may cause evolutionary changes in the fish populations found in such lakes. Hence, a lake visited by a lot of anglers each year may eventually develop fish populations highly suspicious of the fishermen’s lure.

More information can be found in the paper published in Transactions of the American Fisheries Society: Philipp, DP, SJ Cooke, JE Claussen, JB Koppelman, CD Suski and

DP Burkett (2009) Selection for vulnerability to angling in Largemouth Bass. Transactions of the American Fisheries Society 138, pp. 189–199.

A recent study on intersex abnormalities in fish living in the Potomac River watershed carried out by researchers from the U.S. Fish and Wildlife Service and the U.S. Geological Survey showed that at least 82 percent of male smallmouth bass and in 23 percent of the largemouth bass had immature female germ cells (oocytes) in their reproductive organs. This number is even larger than anticipated.

This type of intersex indicates that the fish has been exposed to estrogens or chemicals that mimic the activity of natural hormones. The condition is believed to be caused by hormone-like chemicals, so called endocrine disruptors, found in medicines and a variety of consumer products. Earlier, researchers suspected that the contaminants were entering the Potomac from the wastewater treatment plants that discharge into it, but further sampling showed that the problem existed in areas located upstream from sewage plants as well. Officials are now investigating if multiple chemicals, and not just those from sewage plants, may be responsible. A larger study that includes the entire Potomac River and other East Coast rivers will be launched to find out how widespread the problem actually is.

“At the moment we don’t know the ecological implications of this condition and it could potentially affect the reproductive capability of important sport fish species in the watershed,” said Leopoldo Miranda, Supervisor of the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office.

The Potomac River is the fourth largest river along the Atlantic coast of the USA (in terms of area), with a length of approximately 665 km (383 statute miles) and a drainage area of roughly 38,000 km² (14,700 square miles). It flows into the Chesapeake Bay along the mid-Atlantic coast of the U.S. The river is shared by West Virginia, Maryland, Virginia, and District of Columbia, and all of Washington, D.C., the nation’s capital city, lies within the Potomac watershed.

More information is available in the Intersex fact sheet released by the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office.

Sorry for the silence over Halloween. Posting will now hopefully return to normal with at least one post every or every other day. This first post will be somewhat of a link post catching up on some of the fishy news that happened last week.

First of is an update on the Atlantic Blue fin Tuna. Despite good signs going into the Marrakesh tuna conference the outcome was very bad with the quote for eastern blue fin tuna being set to 22,000 tons, 50 per cent higher than scientific advice. Last years quota was 29,000 tons but it is believed that a total of 61,000 tons were brought ashore when counting illegal catches. These levels are unsustainable and the blue fin tuna populations are near a collapse. You can read more about this here

Another Tuna news. A fisherman out of San Diego is believed to have caught the largest yellow fin tuna ever caught. The tuna weighed in at 381.1-pound. View a video here.

Time to stop talking about tunas and start talking about something completely different, snakeheads. A new study has shown that snakeheads are proving much less damaging to the native fauna than expected. They do not seem to be destroying populations of native fish such as largemouth and peacock bass. The scientist examined the stomach content of 127 snakeheads and found one of the most common pray to be other snakeheads. They found 13 snakeheads, one bluegill, 11 mosquitofish, seven warmouth, two peacock bass, several lizards, bufo toads, small turtles, a rat and a snake. No remains of largemouth bass were found.

Another interesting article posted this last week is this one that tells the story of the mass gharial die of that happened last winter when half the worlds population of this once common animal. Scientist finally thinks they know why this happened. Something that might help save the worlds last 100 specimens.

That is it for this time but I might post more post like this during the week if I decide that there are more news that are to important to miss.