Fantastic Voyage: trying to identify aquatic creatures under microscope

 

FY2022 deadline for informing water monitoring results is January 27th, 2023 (; my post on October 21, 2022). We monitors are busy preparing report now. With stereo microscope, we inspect the specimen collected during the outdoor research. Some veteran volunteers have their own device so that they can prepare the accounts at home. Some, like me, who do not have stereo microscope can ask the Kanagawa Environmental Research Center for usage of the lab. Last month, I reserved a place and did just that. I concentrated myself on the specimens under the microscope in a quiet lab ... a bit different from outdoor activity in forest ... I found it quite a fun!

A close up of one species from damselfly family.
Diamond-shaped jaw is the point
 we should find to identify its species.
It is observable only via microscope.

For the study, the prefecture published a reference book, downloadable free from here. Unfortunately, the publication date was March 2020 when COVID-19 started to halt all human activities on the planet. It did not become much news at that time. Almost 3 years have passed since then, and many have realized it’s a damned good book for practical works at bench. Ministry of Environment also published a reference book, also downloadable from here. But I think Ministerial version is a bit cumbersome to use with microscope. On the other hand, Prefecture’s reference book is concentrated on the creatures probably found in rivers of Kanagawa. I don’t know if such region-specific documentation is useful in the other parts of the planet or, for that matter in another prefectures of Japan. With these caveats, if you’re interested in nature reference books of aquatic lives of Japanese fresh water, please check them. It’s free!

The reference book

The way to identify the specimens stored in a jar is

1. By naked eyes, sort out the specimens in several large categories, starting from a question if their body has apparent sections. If not, next check if it has shell or not. Up to this stage, we identified 3 categories, right? Next, with tweezers gather each category in 3 different petri dishes filled with 80% ethanol. 

2. Set a petri dish under stereo microscope. For the dish of creatures with sections, check if it has legs with sections. If one does not have segmented legs, but has a large head, probably it is a larva for Crambidae family with environmental score 7. If the head is not so large, it would be in a family of Diptera. We proceed to check which species of Diptera it is. On the other hand, if the bug has segmented legs, then check the number of legs … 6, 8, or more? Next, (ctd) … We simply follow Yes/No questions with arrows in the reference until it stops to one particular species that is/is not assigned the score to measure the quality of water where they lived.

The first stage page for identification.

The third stage page for Diptera.

3. We do the above repeatedly until all the specimens in a jar are identified and recorded their existence. Some bugs can be identified in level 2 stage. We plug in the score numbers for an excel sheet. The number of individuals does not matter. So, as in a below photo, even if we find lots of freshwater shrimps, we simply record “We’ve identified freshwater shrimp.”

4. For conclusion, the scores each specimen earned are summed up, then divided by the number of species that has >0 score found in that particular spot. Say, for one place where the specimen was created, if the total score was 45 and 7 species were identified, the score of water quality of that place is 45/7 = 6.43. The higher the score, the better the water quality. Full score is 10, and extremely polluted stream has score 0. Such value of each species is determined by the academic community and the Ministry of Environment who modified English Biological Monitoring Working Party according to the characteristics of Japanese biosphere.

The body of this water spider really glittered gold.
I was charmed …

I found the approach for calculation is easy to use for citizen volunteers like me without college degree for biological studies. The real effort goes to the identification stage using the microscope and the reference book. In today’s post, I’m showing you the photos from microscopic study for specimens found in the water near Higashi-Oshima Camping Ground of Sagamihara City 東大島キャンプ場 (; my post on November 11, 2022). There were lots of lots of freshwater shrimps (Atyidae). Shrimps are easy to identify. Atyidae earns 0, zero, zilch, nada. At least in Kanagawa Prefecture, critical species for endemic shrimp-like creatures in our rivers are the families for Pontogeneia rostrata, Anisogammaridae and Gammaridea. All of them earn score 8, i.e. for very clean water. The rest of the shrimps and shrimp-like things are foreign invaders brought to our water by recreational anglers and tropical fish lovers who used them as bites/feed, then casually threw them away in nearby river as “surplus garbage.” Such introduced species scores zero and do not contribute higher numbers of water quality. It seems to me the scientists for Environmental Research Center are fed up with finding lots of shrimps (and American crawfishes of course; pls see my post on November 11 and 18, 2022) in the midstream and downstream of Sagami 相模川 and Sakawa Rivers 酒匂川. In addition to zero value for water quality measurement, they imply the local ecosystem is highly affected by invasive foreign species. Whether their effect is positive or not would be a different matter, yeah. Lots of shrimps could be good for endemic fishes for their lunch. But …

Another finding I encountered that day was about houses of caddisflies (Trichoptera). I´ve captured many of them near the camping ground. Many larvae of caddisflies live in a house they construct with their favourite material in water and silk from their body. The stuff they choose depend on the water they prefer living. If their place has lots of sands in riverbed, they construct their house made of sands and tiny gravels. If a flow has lots of reeds on the shore, the baby insects use pieces of reeds for their nursery. To do the microscopic study, we have to observe their entire body often hidden in such house. I first thought we could destroy the house with tweezers easily. Those baby caddisflies were in any case dead (; they were specimens!), and could not protect their house, so I thought. WRONG. Dr. Hasegawa, the lead scientist for the project (; my post on October 28, 2022), said, “Oh, Naomi. No, no no. These tiny houses are very strong. We cannot destroy it without crushing the specimen inside. Please softly pull out a specimen from their case.” Yeah. These petite houses were so strong to tear up. Inevitably I had to slowly take the specimens out from them. Very interestingly, the insects’ head which normally pokes out from the house, looked robust, but the rest of their body which stays inside was softer. As they make their house according to the shape of their body, there are several kinds of nests in the family of caddisflies. Long, round, neatly constructed, or simple jumble of leafy bits ... It would reflect each creature’s personality, perhaps. It may sound a bit perverted to call specimen (i.e. dead bugs) in this way, but … they were cute.😊

This house has two-way construction.
Inside is made of sand and silk.
It is then enclosed by the bits of reeds.
The bug inside must have been very diligent.

The specimen pulled out from the nest.
It was about 5mm long.

I have to do the same microscopic study for the other specimens I collected last year by the end of this month. Staying in a wide-open space from the top of the mountain is irresistible. Studying tiny creatures with microscope is fascinating. The nature of forest is all tantalizing from big to small.

The jar and a stereo microscope

If you find environmental issues in waters of Kanagawa Prefecture, please make a contact with Kanagawa Environmental Research Center 神奈川県環境科学センター

1-3-39 Shinomiya, Hiratsuka City, 254-0014
〒254-0014平塚市四之宮1-3-39
Phone: 0463-24-3311
FAX: 0463-24-3300
k-center@k-erc.pref.kanagawa.jp 

https://www.pref.kanagawa.jp/docs/b4f/index.html

Satoyama and Endangered Species: Kanagawa Water Source Monitoring Volunteers 4

 

Sagami River originates from Oshino-Hakkai 忍野八海. Along its journey to Sagami Bay, there are lots of springs on its banks, like the one we’ve visited last week. The water seeps in the forests alongside the river joins the mainstream from such springs. Or, the other satoyama forests do not stand right next to the mainstream of Sagami River. The water from them first comes out to a tributary that eventually joins the mainstream. A tributary itself could have even smaller tributaries, or rills, running along a tiny valley between tiny hills. Sagami River has lots of such systems in its basin. One such place for Sagami River is in Atsugi Kodomonomori Park (Atsugi Kids’ Forest Park あつぎこどもの森公園) in Atsugi City.

The map of Atsugi Kodomonomori Park

Atsugi Kodomonomori Park is 8ha of satoyama forests where volunteers maintain the ecology of forests and rice paddies through their activities. My first impression of the place was like “Oh, it’s similar to Niiharu!” The forest of the Park invited me to stroll freely with lots of vegetations and insects … The place itself deserves one independent post. I spare the introduction of the forest for my later adventure. Today, the topic is aquatic creatures we’ve found in Kodomonomori Park. Certainly, the streams we met there were about max 50cm wide trickles running beside rice paddies volunteers taking care of. At the upstream end of such rivulets, there are small ponds, of 10m in diameter for the biggest. Some ponds are natural, and the others were man-made when yesteryear farmers cultivated the place for their rice and veggies. The tricklets pour into Ogino River 荻野川 whose ultimate water source is in the slopes of Mt. Takatori 鷹取山 (ASL 522.1m) near Lake Miyagase. Some 7km downstream from Kodomonomori Park is near JR Atsugi Station where Ogino River joins the mainstream of Sagami River. For the entire river system of Sagami River, the water from Kodomonomori Park is for downstream part. Very interestingly, the creatures we’ve encountered there were different from those near Camping Ground last week which located a bit upstream from the Kodomonomori Park.

Ogino River.
Could you figure out a white bridge over there?
 Beyond it there is a mouth of a streamlet
 we did a study the other day.

The way water moves was also different. Sure, the rill flows to lower ground but the speed of it was not much for one sunny autumn weekend. The amount of water was also not threatening as we’ve encountered in the mainstream, or in Yadoriki Stream for steep Tanzawa mountains. Its “riverbed” could be sometimes a bedrock, but the majority was mud. The banks were often constructed by retaining walls made of wood panels. Never mind for such man-made structure, wild vegetations are covering the slope of banks, which is a typical scenery of traditional Japanese rice paddies. Unless you’re careful enough you may dunk your feet into muddy stream. The ponds have shores continuing from the vegetation for rivulets, and their offshore have bushes of common reeds. There were lots of dragonflies flying over our heads … Shaking plants as we did last week would yield some catch, but the best approach here could be plunging the landing nets in the mud to capture the living things in one swoop.

The flow of a rill was like this.

The left of the photo is a pond / a rice paddy.
Across the wooden footpath on the right is actually a rivulet.
Could you see lots of satoyama vegetation?

Natural shore of a pond in Kodomonomori Park.
Arrow-leaved tearthumb was in full-bloom.

Have you noticed a small stream running on our left?

Golden-ringed dragonfly was everywhere.

So did I play a mud game in the small trickles of Kodonomomori Park. At the beginning of our research, the pros from Environmental Research Center said “The number of species we’ll encounter here will be far smaller, as the water mass we enter today is definitely smaller.” Hm. I see. The number of species could be limited compared to these from tributaries or mainstream, for sure. But, surprisingly, it was far easier to capture aquatic creatures from the mud in the Park. It was like the dwellers of mud were disrupted their idyllic country life suddenly by our landing nets. There were lots of pond skaters and water striders. My specimen jar captured lavae of several kinds of dragonflies from big to small. River snails were also there. It was so effortless to capture Lefua echigonia, Hotokedojou in Japanese. In contrast, I have not met American crawfish.

The way to collect creatures is,
 first, scoop the mud,
then wash it away in the pond
until mainly leaves and other things remain in the net.
 In this way, we can find our catch in a plastic vat.

My specimen

If American crawfish thrived in Kodomonomori Park, they would eat up all Lefua echigonia for their lunch. Lefua echigonia is Japanese endemic, and endangered species. Once upon a time before industrialization, the fish was ubiquitous in rice paddies surrounded by satoyama forests all over. Now such combo of forest + agricultural field is endangered scenery and so for Lefua echigonia. They need this particular ecosystem for survival. Moreover, the fish is carnivorous, which means it competes with American crawfish. Alas, they do not have super-weapon of craws as the crawfish to fight for survival. It is a common story in Japanese satoyama water where American crawfish is present Lefua echigonia lose their survival game for food. They are eaten for extinction by Americans. Yet, it was so simple on that weekend to capture the fish there. There was not much presence of American crawfish in Kodomonomori Park. Why?

Lots of Lefua echigonia and Japanese freshwater crabs,
sans American crawfish

There is at least one explanation. For years, the Park constantly solicits help from local kids who come to play in the Park to fish American crawfish and bring their catch to the admin office. There, the crawfish becomes roast crawfish to be discarded as garbage (… I think it might be possible to make a gourmet snack from the crawfish if they wish). In addition, when adult volunteers find some trace of crawfish, they execute mop-up operations in their field. The Park was opened in 2016 and such endeavor of citizenry from the beginning protects the endangered species. Once Toshiko Kitagawa 北川淑子of Tokyo University told us in a seminar for Niiharu (; my post on June 24, 2016). Satoyama environment of Japan has been the way to maintain biodiversity of our neighbor. It was replaced by commercial mono-cultivation during the 1950s to the 1980s. Biodiversity of our forests declined rapidly. Once we restore our previous way of satoyama management, some creatures can come back, and prosper as before … so she said. Abundant but endangered Lefua echigonia in Atsugi Kodomonomori Park would be one evidence, I guess.

We also encountered many mantises near the water,
together with

Gordian worms.
It means these poor mantises were infected
and brought to the water to jump in and die
 for the grown-up worm to enjoy aquatic adult life.
 Let’s pray for them …

Oh, I have to tell you one thing, really. When we did our research in the waters of Kodomonomori Park, we obtained permissions from Atsugi City and Kanagawa Prefecture. We showed several green banners around our activity notifying we were doing official water quality survey. If you visit Kodomonomori Park please refrain from picking flowers or fishing Lefua echigonia. They are precious members of biodiverse Park that is now a rare species in suburbs. Thank you indeed for your cooperation. 😉 I have not yet finished microscopic study with the specimen collected during the activities … Hopefully I will meet the deadline for reporting in early January. Later in this blog, I’ll let you know exactly what we’ve found during this year’s field study.

If you find environmental issues in waters of Kanagawa Prefecture, please make a contact with Kanagawa Environmental Research Center 神奈川県環境科学センター

1-3-39 Shinomiya, Hiratsuka City, 254-0014
〒254-0014平塚市四之宮1-3-39
Phone: 0463-24-3311
FAX: 0463-24-3300
k-center@k-erc.pref.kanagawa.jp 

https://www.pref.kanagawa.jp/docs/b4f/index.html

American crawfishes in Sagami River: Kanagawa Water Source Monitoring Volunteers 3

 

Sagami River 相模川 originates from Oshino-hakkai 忍野八海, a vast welling of water where rain and snow falling on Mt Fuji comes out to the surface. It then flows to the east through a narrow valley between Okutama Mountains 奥多摩 and Tanzawa Mountains 丹沢. Infuriatingly for Tokyo, it then turns right, er … to the south I mean, in Sagamihara City which is right in front of Tokyo. (“Oh, if it came to our direction, our water problem would be blah-blah-blah,” you know?) The river runs through so-so-suburban area of Kanagawa, then pours to Sagami Bay near fashionable beach resorts. The way the river flows like

(1) Upstream goes through the relatively flat mountain plateau of Mt. Fuji, which is in Yamanashi Prefecture 山梨県,

(2) Midstream runs through mountainous area, which is like upstream for the other rivers, and

(3) Downstream passes between large human settlements, in a more relaxed manner.

So, for the case of Sagami River, typical feature of nature for “upstream” can be seen in the midstream along Route 20, aka Koshu Kaido Highway 甲州街道, the north-most part of our prefecture. We people of Kanagawa normally get the image of Sagami River from its “downstream” flow, after turning right in Sagamihara. The forests we find along the downstream of Sagami River are often satoyama-kind (in relatively higher altitude) or the city parks. Inevitably, collecting specimens from such part of the river is different from the way we take in Yadoriki Water Source Forest やどりき水源林.

Sagami River at a bit upstream from Tomei Ebina JCT.
Here is about 11km upstream from the mouth
 of the river to Sagami Bay,
i.e., the downstream part of the river.

Today, I tell you my adventure in one of such spots of Sagami River. It was near Higashi-Oshima Camping Ground of Sagamihara City 東大島キャンプ場. The spot we’ve done our research was not in the Camping Ground itself, and I won’t tell you where exactly. Reason? Yeah, the place is right after the Sagami River turns to the south after Lake Tsukui 津久井湖 / Shiroyama Dam 城山ダム. There, the mainstream of the river has lots of water. It flows relatively rapidly. It is not advisable for anybody jumping into the water as it is too risky. Besides, doing fishing at that place needs to purchase fishing rights from the local Fishery Cooperative. I don’t think it is much of the info for you without the explanation of such business deals … (If you want to purchase a day pass for fishing near the camping ground, the Office of Higash-Oshima Camping Ground has an info. Good luck.) In any case, we did not wade in the mainstream of Sagami River, but did our study in a sidepool. There is a spring gathering water from satoyama forests near the Camping Ground. The water from these ag-area first come out to the ground from the spring, then pours into the mainstream via a small exit. Its small bank is full of water-loving grasses and aquatic plants. Such vegetation can also be found along the mainstream, but inside the pool has far more calmer flow. That’s the point for aquatic creatures to survive.

Higashi-Oshima Camping Ground

Before entering parking space for the Camping Ground,
 we are greeted by rice paddies and farmlands.
 The water for such agricultural field joins with
 rainwater dropped on the satoyama forests around,
 and comes out to Sagami River.

Basically, unless it is a fish, the aquatic lives along the river use cleverly the continuation of environment from dry forest to water flow. Amphibians often use mass of water only for mating and tadpole-times. They spend most of their adult life in forest. Insects spend their childhood in water but come out of it when they grow up. Even pond skaters or water striders do not use underwater for their mature days. Grasses and aquatic plants are nice places to cling to for larvae, or to use as corridors between dry land and water area. So, when a spring has such vegetation around, it is the place where we focus to hunt for aquatic creatures. Instead of turning up the stones in riverbeds as in Yadoriki Stream 寄沢, this time we shook water bushes above our landing nets and checked what came out.

The spring pond we studied

According to Mr. Hasegawa of Kanagawa Environmental Research Center, the place we waded in the other day was much larger pond before. Now a sandbank that separated the spring pool and the mainstream became much narrower and the main flow Sagami River is approaching to the calm spring well. We may not have a pool next year once a large typhoon comes. Such is the nature of river … Still, in October 2022, the pond was peaceful enough for us to collect waterborne creatures. Inevitably, our net was stuffed by the remnants of plants we shook, and we searched for the animals hiding in a pile of leaves and stems. At first glance, there was nothing, but once we got used to, we started to spot a small movement of something. We caught these creatures by a small spoon or tweezers and threw them into a jar of 80% ethanol for making specimen. They will be examined under the microscope later for exact identification.

Beyond the sandbank is the mainstream of Sagami River.

But inside the pool is calm.

Pile of leaves and stems …

“Please do not throw fishes and amphibians into the ethanol jar. Instead, catch them in a ziplock or small acrylic aquariums filled with river water and aquatic plants. Take photos of them from many angles, and release. Later we identify them from these pictures.” Oh, I see. So, my jar contained several larvae for aquatic insects and lots of lake prawns + pequeño American crawfishes. “Gee … we have to identify these prawns if they are local or invasive species …” “It seems to us the number of American crawfishes are getting larger.” The pros said. Some invasive species are defined by Ministry of Environment as non-desirable creatures in Japanese wilderness. They compete with native kinds for food, or even devour the locals. American crawfishes are making havoc by acting that way in satoyama environment. Finding them at a point where Sagami River enters downstream is not good news. In contrast, from Yadoriki Stream I have never encountered prawns or crawfishes. It would be the case streams running through deep valleys of Tanzawa are still resisting the invasion of non-native species. Yadoriki Stream behaves nicely as water source. Yeah, the spring pool off the Camping Ground has a nicely clear water where fishes swam around our feet, but …

Making specimens

The water is coming out from the sand. Could you see it?

Even though, downstream part of Sagami River is not dominated by uneasy findings. Next week, I show you another place we did for water-monitoring. Our findings were different, I tell you.

If you find environmental issues in waters of Kanagawa Prefecture, please make a contact with Kanagawa Environmental Research Center 神奈川県環境科学センター

1-3-39 Shinomiya, Hiratsuka City, 254-0014
〒254-0014平塚市四之宮1-3-39
Phone: 0463-24-3311
FAX: 0463-24-3300
k-center@k-erc.pref.kanagawa.jp 

https://www.pref.kanagawa.jp/docs/b4f/index.html