Why sow seagrass seeds in Lake Hamana?

Clam digging has long been a beloved spring tradition at Lake Hamana.

The Bentenjima Pleasure Boat Association has been involved in providing boat services for clam digging for many years, bringing the bounty of Lake Hamana to many people.

However, in recent years, the amount of clams caught in Lake Hamana has decreased significantly. Clam digging at Bentenjima has also been almost completely suspended since 2016.

The decline in clam harvesting isn't just a fishing problem. What's happening to the environment of Lake Hamana?

With that in mind, I am engaged in activities to protect the natural environment of Lake Hamana.

One example of this is the conservation of seagrass.

Seagrass is also called the "cradle of the sea" because it provides a habitat for various small creatures such as clams, shrimp, crabs, and fish.

Protecting the environment in which seagrass grows also helps protect the habitats where creatures in Lake Hamana can live.

Therefore, we continue our efforts to pass on the rich natural environment of Lake Hamana to the next generation through activities such as sowing and cultivating seagrass.

Lake Hamana was once a bustling place, filled with people who came to collect clams and enjoy clam digging.

It won't be easy to restore that view.

It is believed that several factors are involved in the decline of clams, including a shortage of plankton (their food source), predation, and changes in ocean currents.

That's why, rather than relying on just one answer, it's important to take a step-by-step approach, starting with what we can do, while keeping an eye on the environment of Lake Hamana.

Seagrass seeds are very small.

Those tiny seeds will sprout and eventually nurture a new "cradle of the sea" in Lake Hamana.

This seagrass conservation effort is driven by the desire to pass on the rich natural environment of Lake Hamana to future generations.

Would you like to join us in nurturing the future of Lake Hamana?

What you can experience in this tour

1. Meet in front of the pier in Bentenjima Seaside Park

From Hamamatsu Station, take the local line to the south exit of JR Bentenjima Station, which is three stops away. Just a three-minute walk will bring you to Lake Hamana!

If you are coming by car, there is a parking lot next door (410 yen/day)

Please use the red Maisaka Town Symbol Tower as a landmark and come to the pier in Bentenjima Seaside Park.

2. The Story of Seagrass

We'll hear about seagrasses from the boatman (fisherman).

Using photographs and documents, they explain the current situation of Lake Hamana and the role that seagrass plays in the lake.

3. Preparing to sow eelgrass seeds

Lake Hamana is a brackish lake that is connected to the sea.

If seagrass seeds are simply sown, they will be washed out into the sea, so it is necessary to devise ways to keep them within the lake.

We shape wood clay, which decomposes naturally over time, into a cracker-like form and embed seagrass seeds in it. The clay acts as a weight, causing it to sink to the bottom of the lake.

The process of burying the clay will be done by all participants.

*There is a handwashing area, but if you are concerned, please bring thin nitrile gloves (thick rubber gloves or work gloves are not recommended as they will not grip the seeds).

4. After receiving instructions on safety precautions, put on a life jacket and board the boat.

We lend out life jackets in adult and child sizes.

We will board the ship from the pier as soon as preparations are complete.

5. Lake Hamana cruise and seagrass seed planting

You can take a boat tour around the Bentenjima area and, depending on the season, you may also be able to see oyster farms.

Sometimes you'll even see a Shinkansen train passing by as you pass under the iron bridge. This is a great opportunity to see it up close, and is a big hit with children who love Shinkansen trains.

Once we arrive at the place where we will sow the seagrass seeds, we will each sow the seeds according to the boatman's instructions.

The clay acts as a weight, preventing it from being swept away by the waves and allowing it to take root on the lakebed.

6. Take a commemorative photo in front of the Maisaka Town Symbol Tower.

Finally, the boat will pull up close to the red symbol tower, allowing you to take commemorative photos from the boat.

★In spring (from March onwards), you can view the grown seagrass from a boat.

[Kids & Families Welcome! Discover the secrets of Lake Hamana and the seagrass found by boat]

In this experience, you can carefully observe the growth of seagrass using an underwater observation box (rental available).