Special Report 3

Special Report 2

Special Report 1

Take a look at it

Dr. Robin James Smith, Chief Curator at the Lake Biwa Museum, is one of the organizers of this special exhibition “Big Discoveries in a Small World - Exploring the Aquatic Habitats of Shiga” (December 22, 2012 to March 10, 2013). Dr. Smith who is a taxonomist from UK found that Lake Biwa and its surrounding areas are like treasure houses of creatures.

“I’ve found 40 kinds of ostracods and astonishingly 16 of them are the new species, but the ostracods are just parts of our discovery. I’ve also found 152 of new records and 50 of new species from the previous research. We are surrounded by many of unrecognized animals”, Dr. James emphasized that the discovery of the unknown creatures is always possible.

It takes a long procedure to confirm academically that the discovered species is actually “new species”. To make sure that the same species has never recorded before, many of reference books, dissertations and specimens need to be reviewed. It is also necessary to consult other researchers and scientists for their opinions and analyze the DNA. Of course the scientist needs to have keen sense and well trained eyes to identify the small difference of body structure and colors.

Biological researches have been carried on since more than 180 years ago at Lake Biwa and its surroundings. The new discoveries are not only large fish like sweetfish, lecoglossus altivelis, or Crucian carps, Carassius, but also microscopic organisms that their body length is just a few millimeters.

Since the research team extended the study area into environments never have been checked before such as rice fields, water wells, springwater, subterranean rivers, and so on the team discovered so many new species and records. In addition to the mad and sand on the bottom of water, the organs stuck to water plants and weeds were also collected to be checked and examined.

While ostracods are fed by small fish and hydrachnellae, they are predator themselves and sometimes team up to feed on earthworm. Ostracod has hard shells around their body, so 26% of the ostracod, fed by fish is excreted alive.

There are only a few specialists of some particular species of microorganism in Japan. The number of references is limited. There are so many different kinds of microorganisms in the area, so the studies to identify every single of them are very hard even for the specialists. While DNA testing has been common due to the developed molecular biology, the traditional research to identify the species from its body structure and biological characters has not been common practice any more. It is faster and more accurate to check the DNA through the computer data base, but it does not explain everything yet. As an example of that, Dr. Smith points out the difference of underground ostracods and lake ostracods. “Ostracods has a protuberance, called caudal appendage. Ostracods range in flowing water have well developed caudal appendage, while the ostracods in lakes have small ones. It can be thought that the developed caudal appendage is useful and necessary for them to find foods in the sand particles and find a mate in the stream easily,” explains Dr. Smith. He says it’s very important to understand the biology of new species from its body structure as well as the discovery itself.

It is very important to find the groundwater artery to study the biology and their environment. The fact is that soil keeps more water than lakes, ponds, wetland and rivers.

Dr. Mark. J. Grygier is the researcher of crustacean such as the tadpole shrimp or the Fairy shrimp in the wetland like rice fields. In a meantime, he loves Bipalium. Bipalium is in the order of Tricladida in the class of Turbellaria. One of the famous creatures from the same order is the Planaria, which can be cut into half and each parts can regenerate into the complete bodies. The reason why Dr. Grygier is so interested in Bipalium is the fact that it is very rare to find and observe them in the U.S., his home country. In contrast the climate in Japan is wet where Bipalium can range over easily.

“It is really amazing that I can find them everywhere. Some of them are larger than a metre,” said Dr. Grygier. Bipalium is not actually the creature he really studies about but all the curiosities towards the living creature around us are the basic attitude and philosophy of his scientific research.

The land of the area around Lake Biwa is formed with limestone that forms many caves. Dr. Grygier explored deep inside those caves. He had to be very careful and patient to walk safely and find creatures at the same time on the slimy surface in the dark caves for a long period of time. Finally he found a new species of Copepod from one of the cave in Taga-chou, east side of Lake Biwa.

Bathynellacean

It is not only about the new species. Rare species like Bathynellacean is also very important. Although they were found from water well and river bed during this research, there is no specialist of Bathynellacean in Japan. Only one specialist in East Asia lives in Korea. So the biology of the bathynellacean is still unknown and not studied well yet. Dr. Grygier wants to scrutinize on their biology before they disappear because of the loss of habitats with the urbanisation and pollution.

The situation of the Ostracod is no difference. According to Dr. Smith, even though we found many species of ostracods, we still do not know well on the population and the biology of the Ostracod. Simply there are still too many new species to find and put the name on it. Some ostracods can be the indicator of the environmental change because they are very sensitive to the level of oxygen density in the water. Knowing about ostracods is that knowing about our natural environment itself.

Moon Jellyfish

Lake Biwa Museum rears very unique Freshwater Jellyfish, Craspedacusta sowerbii. The diameter is about 3cm. This jellyfish is originally from China, but they range all over Japan, from Hokkaido to Okinawa. The ideal habitat is wetland such as lake and pond shore. Although those bodies of waters can be found in Japan easily it is not easy to find them because they do not emerge at the same places in the same seasons. Interestingly they reproduce themselves by both ways sexual reproduction and asexual reproduction. When they reproduce their offspring without mating they go through the stage called polyp to be a jellyfish. For a while polyp stick on the bottom of the water like sea anemone and eventually develop buds and create colony, then become jerryfish. Amazingly one pond has the same sex of the jerryfish in Japan, north America and Europe while in China the both sex are found in the same pond. It is difficult to rear them for long term. Let’s go to the Lake Biwa Museum while you still have a chance to watch them closely.

Super Unicellular

It is thought that life on earth began 3 billion years ago. It is still unknown what exactly the first being emerged was. It is commonly understood that the first being produced its offspring which produced its' offspring, and gradually increased variation between organisms, then each of them branched out to millions of species. There are many different kinds of microscopic organisms which evolved in the different way from human, mammalians, fowl, fish and so on. They are unicellular, which consist of only one cell. Their sensory system is not divided into mouth, nose, eye, ear, and so on. But unicellular has ability to sense. One proceeds towards light, another recognizes smell and another feels magnetism.

"Unicellular is like a computer chip. One cell has all functions of the sensory systems. It is likely to be misunderstood that unicellular have fewer abilities, but that is wrong", said Yasushi Kusuoka, the Senior Research Scientist.

Gallery C exhibits the culture and life style of the people around the Lake Biwa. The plankton zone in the gallery was expanded in March 2008 after renovation.

4 million years ago, Lake Ohyamada was formed at the area currently Ueno valley in Mie Prefecture. The Lake Ohyamada, also called Old Lake Biwa, gradually moved to north, and reached to the current location 400 thousand years ago. Believe or not, the lake is still moving to north. Probably it will reach to the Japan Sea in the future.

Gallery A shows geological history. You see the gigantic elephant fossil at the centre of the hall. The fossil is big enough for visitors to walk under its belly. This is the Yellow River Elephant's fossil found in China. It is said that the Yellow River Elephant had been small sized and become the ancestor of the Akebono Elephant, Stegondon aurorae. The Akebono Elephant lived in Japan between 2.5 to 1 million years ago. Its fossil has been found from the Lake Biwa area.

The gallery exhibits other fossils from the era of Old Biwa Lake such as fish, shells and plants. You are allowed to touch the fossils of dinosaur's droppings, shark’s teeth, and more.

"Wow, it stinks!!" Some kids blows ups his imagination from the dinosaurs' droppings. According to a guide, many children get surprised by the sharp shark's teeth.

Biwatsubokamuri, Difflugia biwae, is a very rare plankton. Despite the lake water is cleaner now than it was in 1980s, the plankton has not seen since 1981. Nobody knows why it disappeared. In the Gallery C, you can see planktons through a microscope. The fresh plankton is collected from the lake every morning, so you can see it moving actively. Here is an interesting display about dobu. Dobu is swampy place that looks muddy and dirty, but actually full of small lives, plants and algae. The display of enlarged models shows you the eco system of the micro world in dobu liver. There are crayfish, water boatmans and their food such as grain of rice from through drain.

Mr. Yasushi Kusuoka, the Senior Research Scientist, made this display. He says, "Sometimes the ideal environment for a living thing is dirty smelly place for human. Each live has its own suitable condition to live and it's different from others. That is one of the themes that the museum wants the visitors to think about. The display here encourages the visitors to aware what the good environment really is more carefully."

The must see featured fish is the Lake Biwa Catfish. Take a closer look! The huge catfish dwell in the dome tank will amaze you. Two of these catfish are very territorial and wrestle with each other sometimes.

Another interesting fish is ginbuna, gibelio, a kind of carassius. The female fish can produce their offspring without a male.

Gigi the catfish is also unique. She makes noise sound like "gi. gi. gi. gi. gi……"

Ms. Mako Kondo is a guide attending at "Touching Pool". She observes many children reacting differently from the slimy Nigoro-Carassius. Some kids are afraid of the big nails of crayfish. When she finds kids with full of curiosity, she put a crayfish on their hands. That must be an exciting experience for children.

"It is my pleasure to support children to feel and touch the little wild creatures", she says.

The American Paddlefish and the Garpike have been existed since ancient era. The fish keeper Mr. Takashi Okada feeds these living fossils here. They eat powdered food in the aquarium. "They are so sensitive. Sometimes I notice that some of them loose their weight and hard to tell why," says Mr. Okada.

The American Paddlefish opens his big mouth to eat plankton in the wild. The Sturgeon has its mouth at the bottom of his face and eat clams and warms by digging up mud. Let's observe the different shapes and behaviours of fish.

"All species are interdependent".

Lake Biwa has about 50 different kinds of fish and 15 of them are the indigenous. The population is decreasing because of alien fish such as the Blue Gill and the Black Bass. Global warming is considered as another reason. The museum research team studies about endangered species at the conservation centre.