AGO BAY Toward a New Sato-Umi Mie Prefecture Fisheries Research Institute, Please feel free to contact Mie Prefecture Shima City Fisheries Research Institute. TEL ᾉ +81-599-53-0130 Contents More than 50 yyg,gyears ago, Ago Bay was a Sato-Umi*. 1ώGeographical Features, Land Use and History 1 Many kinds of organisms lived in the bay. 2ώFisheries 5 People enjoyed its many blessings, 3ώLiving Beings 9 such as catching clams, fishing and swimming, etc. Understan 4ώTidal Flats and Sea Grass Beds 13 5 Pearl Culture 21 After World War ϩ, ώ social systems changed drastically, 6ώSediment and Water 25 d and Ago Bay lost its identity as a Sato-Umi. 7ώAutomatic Environmental Monitoring System 27 8ώWater Quality 29 “Have you visited Ago Bay recently ?” 9ώSeawater Flow and Seawater Exchange 35 10 Present Status of Ago Bay 43 ḛDo you know its many wonders ?” ώ We wrote this booklet for everyone to be able to have more fun in Ago Bay. T hink 11ώRdTidRed Tides 45 We are making Ago Bay into a “New Sato-Umi”, 12ώHypoxia in Ago Bay 47 And we hope you find this booklet useful! 13ώAccumulation of Organic Materials and 51 Act Purification Capacity όḛSato-Umi” refers to an original Japanese concept that attaches great 14 Towards Nature Restoration in Ago Bay 55 importance to the relationship between local communities and the sea. ώ A Sato-Umi is the coastal area between the actual land and fisheries, with 15ώMore Information 61 high productivity and biodiversity in terms of human activities. 1ώGeographical Features, Land Use and History 1ώGeographical Features, Land Use and History Shape of Ago Bay ẔComplex Coastlinesẕ Mie Prefecture Ago Bay has an intricate coastline, known as a ria-type coast. ẔNo Long Riversẕ Principal rivers are the HIYAMAJI, HAZAKO, NISHIKAWA and MAEGAWA. Areaᾉ26 km2 Coastᾉ140 km Depth Ago Bay is located in the Maxᾉ40m ISE-SHIMA national park Bay mouthᾉ12m Width of bay mouthᾉ1.7 km ẔShima cityẕ In Oct. 2008, Shima City was formed with the merger of 5 towns HUKAYA channel (Ago-cho, Isobe-cho, Shima-cho, Daio-cho and Hamajima-cho) ẔShallow Watersẕ The inner part of the bay is about 5m, with a maximum of about 40m SHIOYA UGATA and a bay mouth depth of 12m. Because the bay mouth is shaped like a HAZAKO SHINMEI bottle neck, water exchange is not simple. KASHIKOJIMA HAMAJIMA OSAKI TATEGAMI Sha llow MASAKI NAKIRI GOZA HUNAKOSHI Cross section KOSHIKA HUKAYA Depth of bay mouthᾉ12m Deepest WAGU KATADA Outer bay Ago Bay HUSEDA ขẟ ෌ẟ Bay mouth Areas around Ago Bay Inner part of bay 1ώGeographical Features, Land Use and History 1ώGeographical Features, Land Use and History Land Use Around Ago Bay History of Ago Bay and Pearl Culture Ago Bay is very famous for pearl culture. Because of its Forest Farmland harmony between nature and pearl culture, Ago Bay was Rice field designated as the first National Park after World War ϩ. Residential Factory Shop Road ẔHistory of Ago Bayẕ Uncultivated The Edo era [Beginning of land reclamation] Golf River 1668῍1704 Rice fields were constructed by land reclamation. The Meiji era [Beginning of pearl culture] 1893 Kokichi Mikimoto produced a semi-circular pearl. The Taisho era [Spread of pearl culture] 1923 Mie Prefectural Fisheries Research Institute started seed collections of ppyearl oysters. The Early Showa era [Reduction of pearl culture] 1932 The Fukaya channel was constructed in Ago Bay. 1942῍1945 Reduction of pearl culture due to WWϩ. The Middle Showa era [Development of pearl culture and setbacks] 1946 Ago Bay was designated the first Japanese National Park. ẔSurrounding Forestsẕ 1950῍ Rapid development of pearl culture. More than 50% of the land is forest. 19.4% of the land is made up 1959 Heavy damage from typhoon “Isewan”. of building lots, factories and roads. 1960 Heavy damage from a tsunami from Chile. Because there is little flat land available around Ago Bay, rice The latter Showa era [Decline of pearl culture fields and farms are not very large. The surrounding forests allow and development of tourism] 1966 Drop in pearl culture from low quality and overproduction. rain to flow right into the bay. ῍ 1976 Pearl oyster seed production was developed. 1988῍ Development of leisure facilities was promoted. 2ώFisheries 2 Fisheries Aquaculture in Ago Bay ώ Laver net Drain off water Press Remove impurities Harvesting machine Harvesting Drying Green laver Miso soup ẔPearl Cultureẕ ẔCultivation of Green Laverẕ Ago Bay is very famous for being the cradle of pearl culture. In Ago Bay, green laver culture is booming. From autumn to In 1893, Koki c hi Mikimoto succee de d in pro duc ing a sem i-cilircular spriling, laver ne ts are p ldlthtdlaced along the coast,and are a tiltypical pearl for the first time in the world. After this success pearl culture sight all over the Bay. Harvested green laver is sold after drying. prospered in Ago Bay. Mie prefecture holds about a 60% share of the green laver in Japan, with Ago Bay contributing about 50% of Mie’s product. 㻝㻢㻜 ඲ᅜThroughout Japan Fishermen work hard to Mie prefecture ୕㔜┴ Green laver absorbs CO2 produce high quality pearls. 㻝㻞㻜 㻡㻜㻜 and nutrients in sea water, Mie prefecture୕㔜┴ Pearl production in Mie 㻤㻜 㻠㻜㻜 and also produces oxygen by 㻟㻜㻜 ⏕⏘㔞䠄㼠䠅 ppygrefecture always ranks high 㻠㻜 ᣽ųᲢᳮᲣ phthotosyn thithesis, thus prov iging 㻞㻜㻜 in Japan. ဃင 㻜 to be very useful to the 㻝㻜㻜 㻝㻥㻠㻡 㻝㻥㻡㻡 㻝㻥㻢㻡 㻝㻥㻣㻡 㻝㻥㻤㻡 㻝㻥㻥㻡 㻞㻜㻜㻡ᖺ 㻜 Changes in pearl production. environment. 㻝㻥㻠㻡 㻝㻥㻡㻡 㻝㻥㻢㻡 㻝㻥㻣㻡 㻝㻥㻤㻡 㻝㻥㻥㻡 㻞㻜㻜㻡ᖺ Changes in green laver production. 2ώFisheries 2ώFisheries Coastal Fisheries in Ago Bay There are various kinds of coastal fisheries in Ago Bay. ẔClamẕ Clams were gathered everywhere in Ago Bay until 1990. However, now there are very few. It is thought ẔSea Cucumberẕ that environmental changes and harmful red tides are Clam Sea cucumbers inhabit the sea bottom. Fishermen catch the main reasons why clams have disappeared. them with a net and hook from their boats. Fisheries of Sea cucumber sea cucumber are very famous around the HAMAJIMA ẔOther Fisheriesẕ region, and are called “HISHI-TSUKI-RYO”. Japanese black porgies and sting rays can be caught by grill nets. Around the bay mouth, Sargassum ẔPrawnẕ fusiforme and Gelidiaceae can be found. Prawns crawl about the sandy sea bottom. Fishermen Ge lidiaceae catch them with grill nets. The seeds of prawns are Prawn produced at the Fish Farm Center, and then these seeds are released into the sea. ẔNemacystis Decipiens and Codium Japanese black porgy Sting ray Sargassum fusiforme Mucronatumẕ Changes of Catchment in Ago Bay Nemacystis decipiens can be gathered in March and Nemacystis decipiens Ẕ ẕ April. Codium mucronatum is collected in summer with a Until 1960 , more than 600t of aquatic products (shellfish, sea cucumbers, net. Nemacystis decipiens can be eaten with vinegar, and prawns and seaweed) were caught in Ago Bay. However, since 1965, this Codium mucronatum is eaten dipped in miso and vinegar amount has decreased dramatically. sauce after boiling. ẔSwimming Crabẕ Codium mucronatum Changes in aquatic products ƦƷ˂Other in Ago Bay ȊȞdzSea cucumber Swimming crabs can be gathered by grill nets or cages ǯȫȞǨȓȷǬǶȟPrawn and crab in early summer. Their claws are so strong they can cut ෙᕹSeaweed through a twig. Swimming crabs can be eaten after ᝝᫏Shellfish ᣽ųᲢᳮᲣ nt boiling. ྒྒ ๤ Amou Swimming crab Pictureᾉ Faculty of bioresources, Mie University, Department of Fisheries, Mie Prefecture 3ώLiving Things 3ώLiving Beings Living Beings in Ago Bay Hibiscus hamabo communities are seen along the coast in Ago Bay. More than 50 years ago, there were a continuous Inner part of the bay natural coastal ecotones (reedsЍtidal flatsЍseagrass beds) . There should be a lot of biodiversity in these areas. However, nature around Ago Bay has being lost because of development, Bay mouth leaving just a few kinds of living things in the coastal area. In order to restore the bay to a “Sato-umi”, we have to N understand the environmental situation. If living beings increase, we will be able to enjoy the many blessings of Ago W E 2km Bay (catching shellfish, fishing, etc.). S Callianassa japonica Hibiscus hamabo Bursatella leachii Clam Zostera marina Sea slug Zostera japonica Reed Inner part Zostera of the bay Reticunassa festi῅a Ilyoplax pusilla Zostera marina Zostera japonica Tidal flat Clypeaster japonicus Sea anemone Hypodytes rubripinnis Apogon niger Halophila ovalis Balloon fish Feather-stars Echinocardium cordatum Seaweed pipefish Bay mouth Zostera bed Nameᾉ Hypodytes rubripinnis Halophila ovalis Zostera japonica A diver 3ώLiving Beings Photo locationᾉ Hamajima Tategami Tategami Tategami Depthᾉ12m 5m 1m 2m About 10cm long . Hypodytes Halophila ovalis grows in shallow Zostera japonica grows in inter tidal To investigate a Zostera bed , divers rubripinnis has strong poison on the areas. The leaves are oval and 1-3cm areas from Hokkaido to Okinawa. The must wear an oxygen tank in Ago Bay. dorsal fin. This fish is nocturnal, and long. leaves are about 3mm wide, and 20cm lives in Zostera beds. long. Clypeaster japonicus Zostera marina Reticunassa festi῅a Callianassa japonica Hamajima Tategami Tategami Tategami 12m 2m 1m 2m About 10cm long. Clypeaster Zostera marina grows in shallow About 3cm long. Reticunassa festi῅a About 5cm long. Callianassa japonica japonicus has a petal-like pattern on areas. The leaves are 0. 5-151.5m lon g lives on the surface of tidal flats. It digs a nest about 1m deep into the its body. Although it doesn’t have and taste sweet. More than 50 years eats dead fish and shellfish. tidal flats. needles, it belongs to the sea urchin ago, Zostera marina was used as family.