【０００１】
【発明の属する技術分野】
本発明は、海岸近くの浅海域の海底や、河川湖沼等に設置する人工漁礁用の人工漁礁部材に関する。
【０００２】
【従来の技術】
自然の状態に保たれている海岸近傍の浅海域や湖沼などでは、海底や湖底に多種多様な藻類が茂って藻場が形成され、藻場には多くの魚類、貝類、サンゴ類等が棲息している。ところが、近年海岸の護岸工事、埋め立て、海砂採取など浅海域における様々な工事によって海藻場が荒らされて海藻の生育が阻害されている。その結果、海藻が次第に減少してついには消滅してしまう現象である「磯焼け」が各地の浅海域で増えつつある。磯焼けとは、海藻場を形成する大型海藻のホンダワラ類、コンブ類、その他多くの海藻が枯死して不毛の海底状態となり、サンゴモ類と呼ばれる海藻体に炭酸カルシウムが沈着したピンク色の硬い石灰海藻体が海底を覆う状態をいう。海藻と、魚類や貝類とは共生関係にあるので、磯焼けが起こると魚類や貝類は棲息できなくなる。磯焼けを防ぐためには、海藻が成長しやすく、かつ魚類が棲息しやすい人工漁礁を海底に設置するのが有効とされている。人工漁礁は、様々な材質により様々な形状のものが開発されている。例えば木材の小片と合成樹脂を混合したものを成形型を用いて成形した人工漁礁部材がある。ミシガン湖、バイカル湖、ビクトリア湖、びわ湖などの淡水湖でも同様の問題がある。
図１２は従来例の人工漁礁部材８０の斜視図である。人工漁礁部材８０は木材の小片（木片）と合成樹脂の混合物の成型体であり、上面に複数の溝８２が形成され、側面に溝８６が形成されている。この人工漁礁部材８０を孔８９を用いて海中の構造物にねじ止めして設置すると、木材の小片が海水等の浸入により膨張して、海藻など藻類の配偶体などの微生物の生育に好適な多孔質有機材となる。人工漁礁部材８０の海水に接する面に溝８２及び８６のような凹部を形成しているので、海水中の海藻の配偶体など微生物が付着しやすくなる。人工漁礁部材８０の成形体の面に溝８２及び８６を設けるには、基本的には押出し成形による製法を用いている。そのため溝の形状は、押出し方向に一方向に延びる形状が一般的である。以下本発明において海藻の語は淡水湖における藻類を含むものとする。また海水の文字も淡水湖等の淡水を含むものとする。したがって海藻場の文言も淡水湖等において海藻場に相当するものを含むものとする。
【０００３】
【特許文献１】
特開平０８−１３１０１６号公報
【特許文献２】
特開２０００−３００１０９号公報
【特許文献３】
特開２０００−３１６４１４号公報
【特許文献４】
特開２０００−１８８９９６号公報
【特許文献５】
特開２００２−０５８３８２号公報
【特許文献６】
特開２００２−０３４３８４号公報
【特許文献７】
特開２００２−２６２７０３号公報
【特許文献８】
特開２００２−２９２６０７号公報
【０００４】
【発明が解決しようとする課題】
人工漁礁において海藻など藻類の育成を行う場合、海底に沈められた人工漁礁部材に海藻などの胞子が自然着床して海藻が生長するにはかなりの期間を要する。海藻の生育を早くするために、海中に設置した人工漁礁部材の近傍もしくは人工漁礁部材自体に「種床」と呼ばれる海藻などの胞子を予め内包させた、例えば繊維質の部材を取付けるのが望ましい。前記種床を水中で浮遊する形態で設置しているものもある。種床を水中に設けることで人工漁礁部材に海藻など藻類の胞子が散布されるので、人工漁礁部材への海藻類の着床が促され、短期間で藻場が形成されやすくなる。このような人工漁礁を海中に設置する場合、設置場所によっては多数の人工漁礁部材が必要となる。人工漁礁に種床を保持するためには、種床を人工漁礁へ個別に固定する必要があるため多大な労力を要する。大型の漁礁部材で漁礁を形成する場合には特に固定作業にクレーンなどの大型の建設機械が必要となるため費用が多大である。
【０００５】
木片と合成樹脂の混合物を成形した人工漁礁部材では、表面近傍の木片が海水など水を含んで膨張し、多孔質になることで海藻の胞子などの着床に適した状態となる。成形したままの状態の人工漁礁部材では表層の木片が樹脂のスキン層で覆われているので直接水に触れる部分が少ない。木片が水中でむき出しになるには、水が樹脂内に浸透して木片に達し、木片が膨張して樹脂のスキン層が破壊される必要があるが、それにはかなりの時間がかかる。そこで、機械加工によって、表層のスキン層を剥ぎ取ることも考えられるが、このような機械加工は、人工漁礁が表面に溝を有するなど複雑な形であるので困難である。人工漁礁部材のサイズの大きいものでは前記機械加工は大変な手間と時間及びコストを要することになる。
【０００６】
海藻の根は、人工漁礁部材の成形体に形成された溝部にからみつくようにして張り付きこれにより海藻が人工漁礁部材に固定される。図１２に示す従来例のように一方向に延びる溝８２に海藻が根を張る場合、根は溝８２の方向に垂直な方向の波や潮流などによる水の力には強いが、溝８２に並行する方向に水の力が加わった場合根の強度は非常に低い。
本発明は、木片と樹脂の混合物を成形した人工漁礁部材の木片に水が速やかに浸透して、藻類の胞子などの着床に適した状態になりやすい人工漁礁部材を提供することを目的とする。また着床して生育した藻類が波や潮流に流されにくい人工漁礁部材を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明の人工漁礁部材は、木片を混ぜた樹脂を射出成形法などによって成形し、表面に様々の方向、様々な形状、様々な深さの溝、細かな凹凸及び孔を形成する。また、藻類の種床を取付けるための取付け部を成形時に形成しておき、藻類の種床を人工漁礁部材に容易に取付けることができるようにする。
細かな凹凸によって表面積が増加するので、人工漁礁部材の表面近傍の木片に水が浸み込みやすくなる。水が浸み込むことにより木片は膨張して藻類の配偶体などの微生物の生育に適した多孔質有機材になる。また人工漁礁部材の表面の凹部には藻類の胞子が着床しやすいために藻場の育成が短期間で可能となる。藻類は、藻類の成長につれて張り出す根が溝や孔に入り込むことにより人工漁礁部材に強固に固着される。そのため本発明の人工漁礁では、様々な方向の波や潮流などの水の力に対しても耐えうる藻類が育成されやすい。
【０００８】
【発明の実施の形態】
請求項１に記載の発明の人工漁礁部材は、プラスチック（合成樹脂）をバインダーとして木材の小片を所定の形状に成形した成形体であり、成形体の水中において水に接する面に大きさ及び高さが様々の多数の凹凸及び溝を設けたことを特徴とする。
木材の小片とプラスチックの成形体が多数の凹凸を有するので、海中や湖中に設置したとき、海水や湖水との接触面積が多く、木材の小片に海水などが浸み込みやすい。木材の小片に水が浸み込むと木材が膨張して多孔質となり、藻類の胞子などの着床に適した状態になる。また、凹凸や溝の中は水流がゆるやかなので、胞子が着床しやすく、また着床した胞子が脱落しにくいので、胞子が生育しやすい環境が形成される。木材の小片には廃木材などを利用するので、木材資源の有効利用を図ることができる。
【０００９】
前記成形体は外周部に段部を有し、複数の成形体を同一面上に配列したとき、隣り合う２つの成形体の段部によって、種床を挿入するための溝が形成されることを特徴とする。前記溝に藻類の種床を挿入することにより、藻類の胞子が人工漁礁部材に着床しやすくなる。
請求項２に記載の発明の人工漁礁部材は、表面を山状に盛り上げている。山状に盛り上げることにより、人工漁礁部材の面の強度が高くなり、比較的厚みが薄い場合でも波などの圧力に耐えることができる。厚みを薄くすることで材料が節減でき、安価な人工漁礁部材が得られる。裏面は材料を節約するため凹形にする。表面を実際の岩礁に似た形状にするために、微小な凹凸や溝が設けられている。
請求項３に記載の発明の人工漁礁部材は、正方形又は長方形の板状部材である。正方形又は長方形にすることで、複数の人工漁礁部材を組合わせて直方体の人工漁礁を構成することができる。
【００１０】
請求項７に記載の発明の人工漁礁部材は、正方形又は長方形であり、隣り合う２つの辺のそれぞれに外方に突出する突起を有し、残りの２つの辺に、複数の人工漁礁部材を同一平面上に接して配置したとき、隣接する他の人工漁礁部材の前記突起が入る穴又は凹部を有することを特徴とする。多数の人工漁礁部材を面上に配列して人工漁礁を構成するとき、隣り合う人工漁礁部材が前記突起と穴、又は突起と凹部により連結されるので、組立作業が容易になる。また水中に設置した後、各人工漁礁部材が波の力などでずれるのを防止することができる。
請求項８に記載の発明の人工漁礁部材は、水に接する面に、藻類の胞子を含ませた種床を取付けるための溝を有することを特徴とする。溝に種床を取付けることにより、藻類の胞子が徐々に水中に放出され、人工漁礁部材の表面に付着する。
請求項９に記載の発明の人工漁礁部材は、水に接する面に、繊維質のひも状の部材に藻類の胞子を含ませた種床を取付けるための溝を有することを特徴とする。溝に繊維質のひも状の種床を取付けることにより、藻類の胞子が徐々に水中に放出され、人工漁礁部材の表面に付着する。
請求項１０に記載の発明の人工漁礁部材は、板状、棒状、パイプ状又は短冊状の形状の種床を有する。
請求項１１に記載の発明の人工漁礁部材は、前記溝の端部に、前記種床の端部を保持するためのフックを設けたことを特徴とする。種床の端部を輪にしておけば、この輪をフックに引っ掛けることにより、種床の人工漁礁部材へ取付作業が敏速かつ確実に行なえる。
【００１１】
請求項１２に記載の発明の人工漁礁部材は、前記溝の端部に、前記種床の端部を固定部材で固定するための孔を有することを特徴とする。種床の端部を前記固定部材を用いて前記孔に固定することにより、種床の人工漁礁部材への取付が敏速かつ確実に行なえる。
請求項１３に記載の発明の人工漁礁部材は、前記溝内に前記種床をシリコン系接着剤により接着することを特徴とする。種床を接着剤で接着するので、人工漁礁部材のフックや取付孔のない部分にも種床を取付けることができる。
請求項１４に記載の発明の人工漁礁部材は、前記溝を形成する両壁面に交互に所定の間隔で、前記種床を前記溝内に保持するための爪を設けたことを特徴とする。種床を溝内に挿入すると、種床は両壁面に交互に所定の間隔で設けた爪によって保持されるので、海流や波などにより種床が溝から離脱するおそれはない。
【００１２】
請求項１５に記載の発明の人工漁礁は、前記請求項１から１３のいずれか１つに記載の人工漁礁部材を、水に浸される構造物の表面に取付けたことを特徴とする。表面に高さが様々な多数の凹凸や溝を有する人工漁礁部材、さらには種床を設けた人工漁礁部材を水中の構造材に取付けて人工漁礁を構成するので、藻類の胞子が着床しやすく、また着床した胞子が藻類に生長しやすい人工漁礁が実現できる。生長した藻類は人工漁礁部材に強固に固定されるので、海流や波などにより人工漁礁部材から離脱しにくく藻類場が形成されやすい人工漁礁が得られる。以下、本発明の人工漁礁部材の好適な実施の形態について図１から図１１を用いて説明する。
【００１３】
《実施の形態１》
本発明の実施の形態１の人工漁礁部材及びこの人工漁礁部材を用いて構成する人工漁礁を図１から図４を参照して説明する。
図１は、本発明の実施の形態１の人工漁礁部材１の斜視図であり、図２は図１のＩＩ−ＩＩ断面図である。図１に示す人工漁礁部材１を用いて図３に一例を示す立方体の人工漁礁５を構成する。
人工漁礁部材１は、木材の小片（木粉及び木片を含む木材のチップであり、以下これらを総称して「木粉」という）とプラスチック（樹脂）を混合して成形した板状の成形品であり射出成形法等で成形される。木粉の原料にはどのような木材を用いても良いが、木材資源の有効利用及び地球環境保護の観点から、廃木材、例えば製材所や各種木工製品の工場や建築現場等で捨てられる廃木材、鋸屑、鉋屑、住宅等の建物や家具を解体する際に排出される廃木材、間伐材等を用いるのが望ましい。木材以外の原料として、バカス（さとうきびの絞り粕）、稲藁、パルプ等のセルロ−ス粉でもよい。木粉の大きさを１０μｍ〜２ｍｍ程度の範囲にすれば、射出成形時に流動性がよいので成形性にすぐれているとともに、木粉とプラスチックが均一に混合された品質のよい成形品が得られる。
【００１４】
このような木粉を樹脂と混合して成形品を射出成形する場合、木粉の含有量は、成形品の重量に対して２０〜８０重量パーセント（ｗｔ％）の範囲で成形性や比重を考慮して選択するのが望ましい。従来から金属イオンは海藻など藻類の育成に有効であることが知られているので、木粉と樹脂に加えて粉末状の金属、例えば、酸化鉄、マグネシウム等の粉末を添加混合すればより好ましい。
前記樹脂には、塩化ビニル樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ウレタン樹脂、ポリウレタン樹脂、ＡＢＳ樹脂、ＡＳ樹脂、ＥＶＡ樹脂、メタクリル樹脂、セルロースアセテート樹脂、ポリカーボネート樹脂、ポリアミド樹脂、ポリエチレンテレフタレート樹脂、ポリスチレン樹脂等の熱可塑性樹脂のバ−ジン原料を用いることもできる。しかし地球資源の有効利用及び地球環境保護の観点からは、水溶性の有害物を含む樹脂など一部有害樹脂を除く廃家電製品の樹脂製外装キャビネット、食品容器トレイやトレイプレス加工時の抜きカス、ＰＰバンド、非塩ビ系の農業用シ−トなど、熱可塑性プラスチックの廃プラスチックを用いることが好ましい。基本的には熱可塑性樹脂が好ましいが、フェノール樹脂、ユリア樹脂、メラミン樹脂、エポキシ樹脂等の熱硬化性樹脂を用いて射出成形や圧縮成形等で成形してもよい。
【００１５】
図１に示すように、人工漁礁部材１はほぼ正方形又は長方形の板状部材であり、好適な寸法の範囲は縦、横がそれぞれ２０〜１５０ｃｍ、最大厚さが２〜１５ｃｍである。人工漁礁部材１の表面３は、図２の断面図に示すように山状に盛上がっている。山状に盛り上げることにより、人工漁礁部材の面の強度が高くなり、比較的厚みが薄い場合でも波などの圧力に耐えることができる。厚みを薄くすることで材料が節減でき、安価な人工漁礁部材が得られる。裏面４は材料を節約するため凹形にするのが好ましい。表面３を実際の岩礁に似た形状にするために、微小な凹凸５や溝６が設けられている。凹凸５の形成のため、実際の岩礁の表面の凹凸を転写するのが望ましいが、実際上岩礁の表面の微小な凹凸５を転写することは困難なので、大まかな岩礁の表面の形状を転写した上に深さが０．１ｍｍから３０ｍｍの凹凸５を形成してもよい。微小な凹凸は、成型金型の面を粗面にすることで容易に実現できる。凹凸５は岩礁の表面の形状に限られるものでなく射出成形で形成可能な形状であればどのような凹凸でもよい。人工漁礁部材１の表面の溝６は、幅が５ｍｍから１００ｍｍ、深さが３ｍｍから１２０ｍｍ程度が好ましく、形はランダムに蛇行しているのが好ましい。人工漁礁部材１には、人工漁礁部材１を湖や海の中に設置された他の構造物に取付けるための取付孔１０が複数個設けられている。図１に示す人工漁礁部材１では取付孔として枠状部２に取付孔１０を設けている。図１に示す人工漁礁部材１の外形は、図３に示すような直方体の人工漁礁５を構成するためには四角形が好ましいが、多角形や円形等どのような形状でもよい。
【００１６】
図３は、人工漁礁部材１を用いて作った人工漁礁７の例の斜視図である。図３に示す人工漁礁７は６面体であり、６面体の各面に９つの人工漁礁部材１が配置されている。人工漁礁７を製作する方法は以下の通りである。まず、図示を省略した型枠の底面及び４つの側面に、それぞれ９つの人工漁礁部材１を表面３を外側に向けて配置し固定する。これにより、４５個の人工漁礁部材１で箱が形成される。次にこの箱の中にコンクリートを流し込み、箱の中をコンクリートで満たす。最後に箱の上面に９つの人工漁礁部材１を配置する。設置時にクレーンで吊り上げるための金具８を必要に応じて設けておくとよい。コンクリートが固まってから型枠を外すと、図３に示す人工漁礁７が得られる。人工漁礁７では、人工漁礁部材１をコンクリ−トを流し込むための型材として利用している。人工漁礁７の内部にはコンクリ−トが充填されているが外面のほぼ全てが人工漁礁部材１で被覆されているのでコンクリ−トの露出部は僅かである。従ってコンクリ−トから水中へ流出するアルカリ成分が抑制され、コンクリートが海藻等藻類の付着や育成を阻害するおそれはない。人工漁礁部材１を用いる人工漁礁は図３に示す形状に限られるものではない。人工漁礁部材１を大型のコンクリ−ト塊に貼り付けてもよい。人工漁礁部材１を取付穴１０を用いて湖や海の岸壁や水中構造物にボルトなどで固定してもよい。あらかじめ別の場所で海藻を発芽させた人工漁礁部材１、又は海藻の胞子を付着させた人工漁礁部材１を、取付穴１０にねじ等の固定手段を通してコンクリート塊に取付けてもよい。コンクリ−ト塊の代わりに、鉄や非毒性ステンレス鋼、その他の金属あるいは、その他の構造用材料で構成された枠組み、金属塊、棒材、多角形材等に人工漁礁部材１を固定することにより人工漁礁を製作することが出来る。
【００１７】
図４は本実施の形態１の他の例の人工漁礁部材２０の一部断面を示す斜視図である。人工漁礁部材２０は、表面３Ａに複数の孔９及び幅の広い溝６Ａを設けている。溝６Ａの幅は５ｍｍから１００ｍｍ程度、深さは３ｍｍから１２０ｍｍ程度が好ましい。溝６Ａの長さは１０ｃｍ〜２０ｃｍ程度で、ランダムに蛇行しているのが好ましい。溝６Ａを複数設けてもよい。溝６Ａの近くに孔９を設けている。孔９の数も人工漁礁部材２０の強度が低下しない範囲で多い方が好ましい。溝６Ａ及び孔９を設けたことにより、図４に示すように、海藻６０の根６１が溝６Ａの中に入り込んでからみつく。また根の一部は孔９を通って人工漁礁部材２０の裏側２０Ａにまで達するので、海藻６０は人工漁礁部材２０に強固に保持される。これにより、台風のときなどの激しい波により海藻６０に強い力が加わっても海藻６０が人工漁礁部材２０から離脱しにくい。尚、溝６Ａの長さは人工漁礁部材の大きさにより、長さを２００ｍｍ以上に設定しても良い。
【００１８】
《実施の形態２》
本発明の実施の形態２の人工漁礁部材３０を図５から図７を参照して説明する。図５の（ａ）は人工漁礁部材３０の上面図、同（ｂ）はＶｂ−Ｖｂ断面図である。図６は複数の人工漁礁部材３０を組合わせる工程を示す斜視図である。図５の（ａ）の上面図において、本実施の形態２の人工漁礁部材３０は、中央部が山状に盛上がった表面３５を有する正方形又は長方形の板状部材であり、周囲には段部３８が設けられている。人工漁礁部材３０の材料及び製法は、前記実施の形態１の人工漁礁部材１と同じである。
【００１９】
人工漁礁部材３０には、隣り合う２つの辺に人工漁礁部材３０の面に平行な方向に突出する突起３１がそれぞれ設けられており、残る２つの辺には穴３２がそれぞれ設けられている。突起３１の直径及び長さは、複数の人工漁礁部材３０を平面上に並べて組合わせるとき突起３１が穴３２に容易に入るようにクリアランスを多目にしている。図５の（ｂ）に示すように、表面３５は前記人工漁礁部材１の表面３と同様に凹凸や溝を有する形状になされている。
本実施の形態２の人工漁礁部材３０では、複数の人工漁礁部材３０を組合わせて人工漁礁を構成するとき、図６の（ａ）及び（ｂ）に示すように、隣り合う人工漁礁部材３０の一方のものの突起３１を他方のものの穴３２に挿入する。これにより平面上に多数の人工漁礁部材３０を配列して大面積の人工漁礁を構成するときの組立作業が容易になるとともに、海中に設置した後で隣り合う人工漁礁部材３０が互いにずれるのを防止できる。図５に示す人工漁礁部材３０は１つの辺に１つの突起３１又は穴３２を有しているが、この数は１つに限られるものでなく複数の突起３１及び穴３２を設けてもよい。
【００２０】
本実施例２の人工漁礁部材３０を平面上で前後左右に配列すると、図６の（ｂ）に示すように、互に隣り合う人工漁礁部材３０の間に双方の段部３８によって溝３８Ａが形成される。この溝３８Ａの中は波などによる水流が穏やかになるので海藻の胞子が付着して生育しやすい。
図７の（ａ）は本実施の形態２の他の例の人工漁礁部材３０Ａの底面を示す図であり、同（ｂ）は右側面図である。この人工漁礁部材３０Ａは四辺形であり、対向する２つの辺に突起３１を有している。残る２つの辺の一方に穴３２を有し、他方にくぼみ３９を有している。人工漁礁部材３０Ａを平面上に配列するとき、一方の人工漁礁部材３０Ａの突起３１を他方の人工漁礁部材の穴３２又はくぼみ３９に挿入する。この構成により、平面上に配列するときの組立作業が簡単になる。
【００２１】
《実施の形態３》
本発明の実施の形態３の人工漁礁部材４０を図８から図１１を参照して説明する。図８は本実施の形態３の人工漁礁部材４０の斜視図、図９は図８のＩＸ−ＩＸ断面図、図１０は図８のＸ−Ｘ断面図、図１１は図８のＸＩ−ＸＩ断面図である。
図８において、人工漁礁部材４０は正方形又は長方形の板状であり、上面の中央領域は前記実施の形態１の人工漁礁部材１と同様の形状になされている。人工漁礁部材４０では、上面の周辺部に溝４７が形成されている。図８に示すものでは、２つの辺に沿ってＬ字形の溝４７が形成されているが、一つの辺にのみ溝を形成してもよい。また３つの辺に沿って「コ」の字形の溝（図示省略）を形成してもよく、４つの辺に沿って周囲を囲むように溝を形成してもよい。溝４７には後で詳しく説明する種床４２が挿入される。人工漁礁部材４０の正方形の少なくとも２つの角部には取付孔１０が設けられている。
【００２２】
人工漁礁部材４０の溝４７内には、繊維の間に海藻の胞子を含ませた種床４２と呼ばれる、両端にそれぞれ輪４３、４４が形成されたひも状の部材を取付ける。種床４２の一方の輪４３をフック４６に引っかけ、他方の輪４４を固定部材４８により取付孔１０を利用して取付ける。種床４２は綿、麻、化学繊維などのひもを用いて作られるのが一般的であるが、ひもに限定されるものではなく、板状、棒状、パイプ状もしくは短冊状など任意の形状にしてもよい。図９に示す断面図に示すように、溝４７には、複数の保持爪４９Ａ、４９Ｂが所定の間隔で設けられている。保持爪４９Ａは溝４７の内側の壁面から突出しており、保持爪４９Ｂは溝４７の外側の壁面から突出している。保持爪４９Ａと４９Ｂは溝４７に沿って交互に配置されている。
【００２３】
溝４７の一方の端部にはほぼ円形の凹部４７Ａが形成され、凹部４７Ａの中央に取付穴１０が形成されている。溝４７の他方の端部にはほぼ円形の凹部４７Ｂが形成され、凹部４７Ｂの中央部にフック４６が設けられている。
フック４６の詳細な構成を図１０を参照して説明する。図１０において、フック４６は、人工漁礁部材４０の底面に略垂直に設けられたポスト５４、及びポスト５４の上端部から底面に略平行に突出した爪５２から構成されている。ポスト５４及び爪５２は人工漁礁部材４０に一体成形で設けるのが好ましい。ポスト５４に種床４２の輪４３を引掛けると、輪４３は爪５２によって保持されるので抜けることはない。種床４２を溝４７の中に挿入するときは、前記のようにまず輪４３をフック４６に引掛ける。次に種床４２を左右に少し曲げながら保持爪４９Ａ、４９Ｂの下に順次挿入してゆく。最後に、輪４４に固定部材４８の軸部４８Ａを挿入し、固定部材４８の爪部４８Ｂを取付穴１０に押し込む。爪部４８Ｂは図１１に示す形状を有し、人工漁礁部材４０の取付孔１０に押し込むと、鉤形部４８Ｃが取付穴１０の内壁に食い込んで抜けなくなる。以上のように、種床４２の取付は簡単な操作で出来るので作業性に優れており、取付けに要する時間も短い。
【００２４】
固定部材４８はポリプロピレンなどの樹脂製が望ましい。しかし省資源の観点からは、人工漁礁部材４０と同じ材料、すなわち木粉又は木片と樹脂の混合物で作るのが望ましい。木粉と樹脂の混合物で作った固定部材４８はややもろい欠点があるが、爪４８Ｂを大きくして機械的強度の高い形状にすることにより、種床４２を孔１０に確実に固定することができる。種床４２が棒状、板状又は短冊状の場合には、種床に孔を設けてねじ止めすればよい。棒状、板状、短冊状の種床は木粉と樹脂の混合物で作るのが望ましい。種々実験した結果木粉と樹脂の混合物を用いた方が、海藻の胞子の初期発芽率が向上することが判った。種床４２を人工漁礁部材にねじ（図示せず）などにより締結する場合は、ねじの腐食による脱落などを防ぐために腐食しにくい材料を用いる必要がある。種床４２の端部をシリコン系の接着剤により人工漁礁部材に接着固定する方法もある。この場合接着剤の固化の時間が必要となるが、ねじ止めなどの労力は軽減できる。図８に示す人工漁礁部材４０では、種床４２を個々の人工漁礁部材４０に取付けているが、図８の人工漁礁部材４０を図３に示すように組合わせて大きな人工漁礁７を構成する場合には、長いひも状の種床（図示省略）を平面上に配列された多数の人工漁礁部材４０の溝４７に順次挿入し、溝部４７の上面近傍に設けたそれぞれの爪４９Ａ、４９Ｂで固定するようにしてもよい。爪４９Ａ、４９Ｂにより、長い種床を隣り合う人工漁礁部材４０の溝４７内に確実に固定することが出来るので潮流等により大きな力が種床に加わっても流出を防止できる。前記長いひも状の種床を、図６の（ｂ）に示すように、前記実施の形態２の人工漁礁部材３０を平面上に配列したときにできる溝３８Ａの中に入れて、所定間隔毎にねじ等によって固定してもよい。
【００２５】
種床４２に海藻の胞子を含ませた人工漁礁部材４０を海中に設置すると、種床４２の繊維の間に含まれていた海藻の胞子は海水中に漂い出て、人工漁礁部材４０の表面の溝６に付着して発芽する。溝６では海水の流れによる水勢が緩和されるので、胞子は海水に流されにくくなり、胞子の着床の割合が比較的高くなる。人工漁礁部材４０を海中に設置すると、海水に浸漬された人工漁礁部材４０の表面に一部露出している木粉に海水が浸透するとともに、表面の樹脂スキン層のピンホ−ルから樹脂スキン層下の木粉に海水が浸透する。その結果人工漁礁部材４０の表面近傍の木粉が膨張し、成形時に木粉を包んでいた樹脂スキン層が破れて海水が徐々に内部の木粉に浸透してゆく。このような状態になると、人工漁礁部材４０は生物の育成に好適な多孔質有機部材となり、種床４２から出る海藻の胞子が付着しやすくなるとともに付着後の胞子は生成してゆく。
【００２６】
【発明の効果】
以上の各実施例で詳細に説明したように、本発明の人工漁礁部材によれば、表面に凹凸を形成するとともに、ランダムな方向の溝及び複数の孔をあらかじめ形成しているので、海藻の胞子が付着して生育しやすい。また生育した海藻の根が溝の中を各方向に伸びて行くとともに孔を通って人工漁礁部材の裏側にまで達して人工漁礁部材にからみつくことで、海藻は強固に固定され潮流等により流されにくくなる。海藻は人工漁礁部材に強固に固定されることにより生長しかつ繁茂する。海藻の繁茂により藻場が形成されると、藻場に魚貝類等が生息しはじめ、海洋資源の育成に多大の効果を与える。また本発明の人工漁礁部材は海岸近辺の海藻の育成とともに、河川、湖沼等の護岸壁などにも利用可能であり、環境再生のための利用範囲が広い。海藻の種床の保持が容易であるとともに、海藻の胞子の着床が促進されるので、短期間に海藻場の育成が可能となる。海藻の成長にともなって張り出す根の固着が強固であるので各方向の波や潮流などの水の抵抗に対しても耐えうる藻場を提供できる。本発明の人工漁礁部材は原材料として、廃木材や廃プラスチックを用いることができるので産業廃棄物の利用用途が広がり環境保護にも貢献できる。又、藻場形成のみならず、サンゴ礁の回復にも本件人工漁礁部材および人工漁礁を利用すると効果があると共に、魚介類等の着床や養殖に有効に利用ができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１の人工漁礁部材の斜視図
【図２】本発明の実施の形態１の人工漁礁部材のＩＩ−ＩＩ断面図
【図３】本発明の実施の形態１の人工漁礁部材により構成した人工漁礁の斜視図
【図４】本発明の実施の形態１の人工漁礁部材に海藻が生えた状態を示す一部断面の斜視図
【図５】（ａ）は本発明の実施の形態２の人工漁礁部材の上面図
（ｂ）は（ａ）のＶｂ−Ｖｂ断面図
【図６】（ａ）は本発明の実施の形態２の人工漁礁部材の連結工程を示す斜視図
（ｂ）は実施の形態２の人工漁礁部材の連結した状態を示す側面図
【図７】（ａ）は本発明の実施の形態２の人工漁礁部材の他の例を示す底面図
（ｂ）は同右側面図
【図８】本発明の実施の形態３の人工漁礁部材の斜視図
【図９】図８のＩＸ−ＩＸ断面図
【図１０】図９のＸ−Ｘ断面図
【図１１】図８のＸＩ−ＸＩ断面図
【図１２】従来の人工漁礁部材の斜視図
【符号の説明】
１、２０、３０、３０Ａ、４０ 人工漁礁部材
３、３Ａ、３５ 表面
４ 裏面
５ 凹凸
６、６Ａ、４７溝
７ 人工漁礁
８ 金具
９ 孔
１０ 取付孔
３１ 突起
３２ 穴
３８ 段部
３９ くぼみ
４２ 種床
４６ フック
４８ 固定部材
４９Ａ、４９Ｂ 爪
６０ 海藻
６１ 根[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an artificial reef member for an artificial reef to be installed on a seabed in a shallow sea area near a coast, a river lake, or the like.
[0002]
[Prior art]
In shallow waters and lakes near the coast that are kept in a natural state, a variety of algae grow on the seabed and the bottom of the lake, and algae beds are formed, and many fishes, shellfish, corals, etc. live in the seaweed beds. doing. However, in recent years, seaweed beds have been damaged by various works in shallow water areas such as coastal revetment, land reclamation, and sea sand collection, and the growth of seaweed has been hindered. As a result, “sea bream”, a phenomenon in which seaweed gradually decreases and eventually disappears, is increasing in shallow water areas. Firewood burnt is a large, hard seaweed of the seaweeds such as Honda walla, kombu, and many other seaweeds that die into a barren seabed. A state where seaweed bodies cover the sea floor. Since seaweed and fish and shellfish are in a symbiotic relationship, fish and shellfish can no longer live if salmon burning occurs. In order to prevent firewood burning, it is effective to install an artificial reef on the seabed where seaweed grows easily and fish live. Artificial fishing reefs have been developed in various shapes and materials. For example, there is an artificial reef member obtained by molding a mixture of a small piece of wood and a synthetic resin using a molding die. Similar problems exist in freshwater lakes such as Lake Michigan, Lake Baikal, Lake Victoria, and Lake Biwa.
FIG. 12 is a perspective view of a conventional artificial reef member 80. The artificial reef member 80 is a molded body of a mixture of a small piece of wood (wood piece) and a synthetic resin, and has a plurality of grooves 82 formed on the top surface and grooves 86 formed on the side surfaces. When the artificial reef member 80 is screwed and installed on a structure in the sea using the hole 89, a small piece of wood expands due to intrusion of seawater and the like, and is suitable for the growth of microorganisms such as seaweeds such as seaweed. It becomes a porous organic material. Since the concave portions such as the grooves 82 and 86 are formed on the surface of the artificial reef member 80 in contact with the seawater, microorganisms such as seaweed gametophytes in the seawater are likely to adhere. In order to provide the grooves 82 and 86 on the surface of the molded body of the artificial reef member 80, a manufacturing method by extrusion molding is basically used. Therefore, the shape of the groove is generally a shape extending in one direction in the extrusion direction. Hereinafter, in the present invention, the term seaweed includes algae in a freshwater lake. The letter of seawater shall also include freshwater such as freshwater lakes. Therefore, the term “seaweed basin” includes those corresponding to the seaweed basin in freshwater lakes and the like.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 08-13016
[Patent Document 2]
JP 2000-300109 A
[Patent Document 3]
JP 2000-316414 A
[Patent Document 4]
JP 2000-188996 A
[Patent Document 5]
JP 2002-058382 A
[Patent Document 6]
JP 2002-034384 A
[Patent Document 7]
JP 2002-262703 A
[Patent Document 8]
JP 2002-292607 A
[0004]
[Problems to be solved by the invention]
When algae such as seaweed are cultivated on an artificial fishing reef, it takes a considerable period of time for spores such as seaweed to naturally land on an artificial fishing reef member submerged in the seabed and the seaweed grow. In order to speed up the growth of seaweeds, it is desirable to install, for example, a fiber member, in which spores such as seaweed called “seed beds” are encapsulated in the vicinity of the artificial reef member installed in the sea or in the artificial reef member itself. . In some cases, the seed bed is installed in a floating form in water. By providing a seed bed in the water, spores of seaweed and other algae are sprinkled on the artificial reef member, so that the seaweed is laid on the artificial reef member, and an algae field is easily formed in a short period of time. When such an artificial reef is installed in the sea, a large number of artificial reef members are required depending on the installation location. In order to hold the seed bed on the artificial reef, it is necessary to fix the seed bed individually to the artificial reef, so a great deal of labor is required. When a reef is formed with a large reef member, a large construction machine such as a crane is required for fixing work, which is very expensive.
[0005]
In an artificial reef member obtained by molding a mixture of wood pieces and synthetic resin, the wood pieces in the vicinity of the surface expand and contain water such as seawater, and become porous, so that they are suitable for landing seaweed spores and the like. In the artificial reef member as-formed, the surface wood pieces are covered with a resin skin layer, so there are few parts that directly come into contact with water. In order for a piece of wood to be exposed in water, it is necessary for water to penetrate into the resin and reach the piece of wood, and the piece of wood expands to destroy the resin skin layer, which takes a considerable amount of time. Therefore, it is conceivable that the skin layer of the surface layer is peeled off by machining, but such machining is difficult because the artificial reef has a complicated shape such as a groove on the surface. If the artificial reef member has a large size, the machining requires a lot of labor, time and cost.
[0006]
The seaweed root sticks to the groove portion formed in the molded body of the artificial reef member, thereby fixing the seaweed to the artificial reef member. When the seaweed has roots in the groove 82 extending in one direction as in the conventional example shown in FIG. 12, the roots are strong against water force caused by waves or tides in a direction perpendicular to the direction of the groove 82, but The root strength is very low when water forces are applied in parallel directions.
An object of the present invention is to provide an artificial reef member that is likely to be in a state suitable for implantation of algae spores such that water quickly penetrates into a piece of the artificial reef member formed with a mixture of a piece of wood and a resin. To do. It is another object of the present invention to provide an artificial reef member in which algae grown on the ground are not easily washed away by waves and tides.
[0007]
[Means for Solving the Problems]
The artificial reef member of the present invention is formed by molding resin mixed with wood pieces by an injection molding method or the like to form grooves, grooves and fine irregularities and holes of various directions, various shapes, various depths on the surface. Further, an attachment portion for attaching the algae seed bed is formed at the time of molding so that the algae seed bed can be easily attached to the artificial reef member.
Since the surface area is increased by the fine irregularities, water can easily infiltrate into a piece of wood near the surface of the artificial reef member. When the water soaks in, the piece of wood expands to become a porous organic material suitable for the growth of microorganisms such as algae gametophytes. In addition, algae spores can be easily deposited in the recesses on the surface of the artificial reef member, so that algae can be grown in a short period of time. The algae are firmly fixed to the artificial fishing reef member by the roots that protrude as the algae grow into the grooves and holes. Therefore, in the artificial reef of the present invention, algae that can withstand the power of water such as waves and tides in various directions are easily cultivated.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The artificial reef member according to the first aspect of the present invention is a molded body in which a small piece of wood is molded into a predetermined shape using plastic (synthetic resin) as a binder, and the size and height of the molded body in contact with water in water. A large number of irregularities and grooves are provided.
Since a small piece of wood and a plastic molded body have a large number of irregularities, when installed in the sea or in a lake, there is a large contact area with seawater or lake water, and seawater or the like tends to soak into the small piece of wood. When water soaks into a small piece of wood, the wood expands and becomes porous, making it suitable for implantation of algal spores. In addition, since the water flow is gentle in the unevenness and the groove, the spores are likely to be implanted, and the implanted spores are difficult to drop off, so that an environment in which the spores are likely to grow is formed. Since waste wood is used for the small pieces of wood, it is possible to effectively use wood resources.
[0009]
The molded bodyHas a step portion on the outer periphery, and when a plurality of molded bodies are arranged on the same surface, a groove for inserting a seed bed is formed by the step portions of two adjacent formed bodies. To do. By inserting an algae seed bed into the groove, algae spores can be easily landed on the artificial reef member.
The artificial reef member according to the second aspect of the present invention has the surface raised in a mountain shape. Raising the mountain shape increases the strength of the surface of the artificial reef member, and can withstand pressure such as waves even when the thickness is relatively thin. By reducing the thickness, the material can be saved and an inexpensive artificial reef member can be obtained. The back side is concave to save material. In order to make the surface resemble the shape of an actual reef, minute irregularities and grooves are provided.
The artificial reef member of the invention according to claim 3 is a square or rectangular plate member. By making it square or rectangular, a rectangular parallelepiped artificial reef can be configured by combining a plurality of artificial reef members.
[0010]
The artificial reef member of the invention according to claim 7 is a square or a rectangle, has a protrusion protruding outward on each of two adjacent sides, and a plurality of artificial reef members on the remaining two sides. When it arrange | positions in contact with the same plane, it has the hole or recessed part into which the said protrusion of another adjacent artificial reef member enters, It is characterized by the above-mentioned. When an artificial reef is configured by arranging a large number of artificial reef members on the surface, adjacent artificial reef members are connected by the protrusions and holes or the protrusions and the recesses, so that the assembling work is facilitated. Moreover, after installing in water, it can prevent that each artificial reef member shifts | deviates by the force of a wave.
An artificial reef member according to an eighth aspect of the invention is characterized in that a groove for attaching a seed bed containing algal spores is provided on a surface in contact with water. By attaching a seed bed to the groove, algal spores are gradually released into the water and adhere to the surface of the artificial reef member.
The artificial reef member of the invention according to claim 9 is characterized in that a groove for attaching a seed bed in which algal spores are contained in a fibrous string-like member is provided on the surface in contact with water. By attaching a fibrous string-like seed bed to the groove, algal spores are gradually released into the water and adhere to the surface of the artificial reef member.
The artificial reef member of the invention described in claim 10 has a seed bed in the form of a plate, rod, pipe or strip.
The artificial reef member according to an eleventh aspect of the present invention is characterized in that a hook for holding the end of the seed bed is provided at the end of the groove. If the end portion of the seed bed is made into a ring, the attaching operation to the artificial reef member of the seed bed can be performed quickly and reliably by hooking this ring on the hook.
[0011]
The artificial reef member according to a twelfth aspect of the present invention is characterized in that a hole for fixing the end of the seed bed with a fixing member is provided at the end of the groove. By fixing the end of the seed bed to the hole using the fixing member, the seed bed can be quickly and reliably attached to the artificial reef member.
The artificial reef member of the invention described in claim 13 is characterized in that the seed bed is bonded in the groove with a silicon-based adhesive. Since the seed bed is bonded with an adhesive, the seed bed can be attached to a portion of the artificial reef member that does not have a hook or attachment hole.
The artificial reef member according to claim 14 is characterized in that claws for holding the seed bed in the groove are provided alternately at predetermined intervals on both wall surfaces forming the groove. When the seed bed is inserted into the groove, the seed bed is held by claws alternately provided at predetermined intervals on both wall surfaces, so that there is no possibility that the seed bed is detached from the groove due to ocean currents or waves.
[0012]
An artificial reef according to a fifteenth aspect of the invention is characterized in that the artificial reef member according to any one of the first to thirteenth aspects is attached to the surface of a structure immersed in water. Artificial fishing reef members with numerous irregularities and grooves on the surface, as well as artificial reef members with seed beds are attached to underwater structural materials to construct artificial reefs, so that algae spores land An artificial reef that is easy to grow and the spores that have been implanted to grow algae can be realized. Since the grown algae are firmly fixed to the artificial reef member, it is possible to obtain an artificial reef that is unlikely to be detached from the artificial reef member due to ocean currents or waves, and in which an algae field is easily formed. Hereinafter, preferred embodiments of the artificial reef member of the present invention will be described with reference to FIGS. 1 to 11.
[0013]
Embodiment 1
An artificial reef member according to Embodiment 1 of the present invention and an artificial reef constructed using this artificial reef member will be described with reference to FIGS. 1 to 4.
FIG. 1 is a perspective view of an artificial reef member 1 according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. A cubic artificial reef 5 shown as an example in FIG. 3 is constructed using the artificial reef member 1 shown in FIG. 1.
The artificial reef member 1 is a plate-like molded product formed by mixing small pieces of wood (wood chips containing wood powder and wood pieces, hereinafter collectively referred to as “wood powder”) and plastic (resin). It is molded by an injection molding method or the like. Any wood can be used as a raw material for wood flour, but from the viewpoint of effective use of wood resources and protection of the global environment, waste wood, for example, waste discarded at sawmills, factories of various woodworking products, construction sites, etc. It is desirable to use wood, sawdust, sawdust, waste wood, thinned wood, etc. discharged when demolishing buildings and furniture such as houses. As raw materials other than wood, cellulose powder such as bacus (sugar cane squeezed), rice straw, and pulp may be used. If the size of the wood powder is in the range of about 10 μm to 2 mm, the fluidity is good at the time of injection molding, so that the moldability is excellent, and a good quality molded product in which wood powder and plastic are uniformly mixed is obtained. .
[0014]
When such a wood powder is mixed with a resin and a molded product is injection molded, the content of the wood powder is within a range of 20 to 80 weight percent (wt%) of the weight of the molded product. It is desirable to select in consideration. Conventionally, metal ions are known to be effective for the growth of algae such as seaweed, so it is more preferable to add and mix powdered metals such as iron oxide and magnesium in addition to wood flour and resin. .
Examples of the resin include vinyl chloride resin, polyethylene resin, polypropylene resin, urethane resin, polyurethane resin, ABS resin, AS resin, EVA resin, methacrylic resin, cellulose acetate resin, polycarbonate resin, polyamide resin, polyethylene terephthalate resin, polystyrene resin, etc. The virgin raw material of the thermoplastic resin can also be used. However, from the viewpoint of effective use of global resources and protection of the global environment, resin exterior cabinets for waste household electrical appliances excluding some harmful resins such as resins containing water-soluble harmful substances, food container trays, and wastes from tray press processing It is preferable to use thermoplastic waste plastic such as PP band and non-vinyl chloride agricultural sheet. Basically, a thermoplastic resin is preferable, but it may be formed by injection molding, compression molding, or the like using a thermosetting resin such as a phenol resin, a urea resin, a melamine resin, or an epoxy resin.
[0015]
As shown in FIG. 1, the artificial reef member 1 is a substantially square or rectangular plate member, and preferable dimensions are 20 to 150 cm in length and width, and a maximum thickness of 2 to 15 cm. The surface 3 of the artificial reef member 1 is raised in a mountain shape as shown in the sectional view of FIG. Raising the mountain shape increases the strength of the surface of the artificial reef member, and can withstand pressure such as waves even when the thickness is relatively thin. By reducing the thickness, the material can be saved and an inexpensive artificial reef member can be obtained. The back surface 4 is preferably concave to save material. In order to make the surface 3 a shape similar to an actual reef, minute irregularities 5 and grooves 6 are provided. Although it is desirable to transfer the surface irregularities of the actual reef to form the unevenness 5, it is actually difficult to transfer the minute unevenness 5 on the surface of the reef, so the rough shape of the surface of the reef was transferred The unevenness 5 having a depth of 0.1 mm to 30 mm may be formed on the top. Minute irregularities can be easily realized by making the surface of the molding die rough. The unevenness 5 is not limited to the shape of the surface of the reef, but may be any unevenness as long as it can be formed by injection molding. The groove 6 on the surface of the artificial reef member 1 preferably has a width of about 5 mm to 100 mm and a depth of about 3 mm to 120 mm, and preferably has a meandering shape at random. The artificial reef member 1 is provided with a plurality of attachment holes 10 for attaching the artificial reef member 1 to other structures installed in a lake or the sea. In the artificial reef member 1 shown in FIG. 1, the attachment hole 10 is provided in the frame-like part 2 as an attachment hole. The outer shape of the artificial reef member 1 shown in FIG. 1 is preferably a quadrangle in order to form a rectangular parallelepiped artificial reef 5 as shown in FIG. 3, but may be any shape such as a polygon or a circle.
[0016]
FIG. 3 is a perspective view of an example of the artificial reef 7 made using the artificial reef member 1. The artificial reef 7 shown in FIG. 3 is a hexahedron, and nine artificial reef members 1 are arranged on each side of the hexahedron. The method for producing the artificial reef 7 is as follows. First, nine artificial reef members 1 are respectively arranged and fixed on the bottom surface and four side surfaces of the mold form (not shown) with the surface 3 facing outward. Thereby, a box is formed with 45 artificial reef members 1. Next, pour concrete into this box and fill the box with concrete. Finally, nine artificial reef members 1 are arranged on the upper surface of the box. A metal fitting 8 for lifting with a crane at the time of installation may be provided as necessary. When the formwork is removed after the concrete has hardened, an artificial reef 7 shown in FIG. 3 is obtained. In the artificial reef 7, the artificial reef member 1 is used as a mold material for pouring the concrete. The inside of the artificial reef 7 is filled with concrete, but almost all of the outer surface is covered with the artificial reef member 1, so that the exposed portion of the concrete is slight. Therefore, the alkaline component flowing out from the concrete into the water is suppressed, and there is no possibility that the concrete will inhibit the adhesion and growth of algae such as seaweed. The artificial reef using the artificial reef member 1 is not limited to the shape shown in FIG. The artificial reef member 1 may be attached to a large concrete block. The artificial reef member 1 may be fixed to a lake, a sea quay or an underwater structure using a mounting hole 10 with a bolt or the like. The artificial reef member 1 in which seaweed has been germinated in another place in advance or the artificial reef member 1 on which seaweed spores are attached may be attached to the concrete block through fixing means such as screws in the attachment hole 10. The artificial reef member 1 is fixed to a frame, a metal block, a bar, a polygonal member, or the like made of iron, non-toxic stainless steel, other metals, or other structural materials instead of a concrete block. An artificial fishing reef can be manufactured.
[0017]
FIG. 4 is a perspective view showing a partial cross section of an artificial reef member 20 of another example of the first embodiment. The artificial reef member 20 is provided with a plurality of holes 9 and a wide groove 6A on the surface 3A. The width of the groove 6A is preferably about 5 mm to 100 mm, and the depth is preferably about 3 mm to 120 mm. The length of the groove 6A is about 10 cm to 20 cm, and is preferably meandering randomly. A plurality of grooves 6A may be provided. A hole 9 is provided near the groove 6A. It is preferable that the number of holes 9 is large as long as the strength of the artificial reef member 20 does not decrease. By providing the groove 6A and the hole 9, as shown in FIG. 4, the root 61 of the seaweed 60 enters the groove 6A and is caught. Moreover, since a part of the root reaches the back side 20 </ b> A of the artificial reef member 20 through the hole 9, the seaweed 60 is firmly held by the artificial reef member 20. Thereby, even if a strong force is applied to the seaweed 60 by intense waves such as during a typhoon, the seaweed 60 is unlikely to be detached from the artificial reef member 20. The length of the groove 6A may be set to 200 mm or more depending on the size of the artificial fishing reef member.
[0018]
<< Embodiment 2 >>
An artificial reef member 30 according to a second embodiment of the present invention will be described with reference to FIGS. 5A is a top view of the artificial reef member 30, and FIG. 5B is a Vb-Vb sectional view. FIG. 6 is a perspective view showing a process of combining a plurality of artificial reef members 30. In the top view of FIG. 5 (a), the artificial reef member 30 of the second embodiment is a square or rectangular plate-like member having a surface 35 whose central portion is raised in a mountain shape, and has a step around it. A portion 38 is provided. The material and manufacturing method of the artificial reef member 30 are the same as those of the artificial reef member 1 of the first embodiment.
[0019]
The artificial reef member 30 is provided with protrusions 31 projecting in the direction parallel to the surface of the artificial reef member 30 on two adjacent sides, and holes 32 are provided on the remaining two sides. The diameter and length of the protrusion 31 allow for a large clearance so that the protrusion 31 can easily enter the hole 32 when a plurality of artificial reef members 30 are combined in a plane. As shown in (b) of FIG. 5, the surface 35 has a shape having irregularities and grooves, like the surface 3 of the artificial reef member 1.
In the artificial reef member 30 of the second embodiment, when a plurality of artificial reef members 30 are combined to form an artificial reef, adjacent artificial reef members 30 as shown in FIGS. The one protrusion 31 is inserted into the other hole 32. This facilitates assembly work when arranging a large number of artificial reef members by arranging a large number of artificial reef members 30 on a plane, and the adjacent artificial reef members 30 are shifted from each other after being installed in the sea. Can be prevented. The artificial reef member 30 shown in FIG. 5 has one protrusion 31 or hole 32 on one side, but this number is not limited to one, and a plurality of protrusions 31 and holes 32 may be provided. .
[0020]
When the artificial reef members 30 according to the second embodiment are arranged in the front-rear and left-right directions on the plane, as shown in FIG. 6B, the grooves 38 </ b> A are formed between the adjacent artificial reef members 30 by the two step portions 38. It is formed. In this groove 38A, the water flow due to waves and the like becomes gentle, so the spores of seaweed adhere and grow easily.
(A) of FIG. 7 is a figure which shows the bottom face of the artificial reef member 30A of the other example of this Embodiment 2, and the same (b) is a right view. The artificial reef member 30A has a quadrilateral shape and has protrusions 31 on two opposing sides. One of the remaining two sides has a hole 32 and the other has a recess 39. When the artificial reef members 30A are arranged on a plane, the protrusion 31 of one artificial reef member 30A is inserted into the hole 32 or the recess 39 of the other artificial reef member. With this configuration, assembly work when arranged on a plane is simplified.
[0021]
<< Embodiment 3 >>
An artificial reef member 40 according to Embodiment 3 of the present invention will be described with reference to FIGS. 8 is a perspective view of the artificial reef member 40 of the third embodiment, FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8, FIG. 10 is a cross-sectional view taken along the line XX in FIG. It is sectional drawing.
In FIG. 8, the artificial reef member 40 has a square or rectangular plate shape, and the central region of the upper surface has the same shape as the artificial reef member 1 of the first embodiment. In the artificial reef member 40, a groove 47 is formed in the periphery of the upper surface. In FIG. 8, the L-shaped groove 47 is formed along two sides, but the groove may be formed only on one side. Further, a “U” -shaped groove (not shown) may be formed along the three sides, and the groove may be formed so as to surround the periphery along the four sides. A seed bed 42 described in detail later is inserted into the groove 47. Attachment holes 10 are provided in at least two corners of the square of the artificial reef member 40.
[0022]
In the groove 47 of the artificial reef member 40, a string-like member called a seed bed 42 in which seaweed spores are included between fibers and having rings 43 and 44 formed at both ends is attached. One wheel 43 of the seed bed 42 is hooked on the hook 46, and the other wheel 44 is attached by the fixing member 48 using the attachment hole 10. The seed bed 42 is generally made using a string of cotton, hemp, chemical fiber, etc., but is not limited to a string, and can be any shape such as a plate, bar, pipe or strip. May be. As shown in the cross-sectional view shown in FIG. 9, the groove 47 is provided with a plurality of holding claws 49A and 49B at a predetermined interval. The holding claws 49 </ b> A protrude from the inner wall surface of the groove 47, and the holding claws 49 </ b> B protrude from the outer wall surface of the groove 47. The holding claws 49 </ b> A and 49 </ b> B are alternately arranged along the groove 47.
[0023]
A substantially circular recess 47A is formed at one end of the groove 47, and the mounting hole 10 is formed at the center of the recess 47A. A substantially circular recess 47B is formed at the other end of the groove 47, and a hook 46 is provided at the center of the recess 47B.
A detailed configuration of the hook 46 will be described with reference to FIG. In FIG. 10, the hook 46 includes a post 54 provided substantially perpendicular to the bottom surface of the artificial reef member 40, and a claw 52 projecting substantially parallel to the bottom surface from the upper end portion of the post 54. The post 54 and the claw 52 are preferably provided integrally with the artificial reef member 40. When the ring 43 of the seed bed 42 is hooked on the post 54, the ring 43 is held by the claw 52, so that it does not come off. When the seed bed 42 is inserted into the groove 47, the ring 43 is first hooked on the hook 46 as described above. Next, the seed bed 42 is sequentially inserted under the holding claws 49A and 49B while slightly bending left and right. Finally, the shaft portion 48 </ b> A of the fixing member 48 is inserted into the ring 44, and the claw portion 48 </ b> B of the fixing member 48 is pushed into the mounting hole 10. The claw portion 48B has the shape shown in FIG. As described above, since the seed bed 42 can be attached by a simple operation, the workability is excellent and the time required for the attachment is short.
[0024]
The fixing member 48 is preferably made of resin such as polypropylene. However, from the viewpoint of resource saving, it is desirable to make the same material as the artificial reef member 40, that is, wood powder or a mixture of wood pieces and resin. The fixing member 48 made of a mixture of wood powder and resin has a somewhat fragile defect, but the seed bed 42 can be reliably fixed to the hole 10 by increasing the size of the claw 48B to a shape with high mechanical strength. it can. If the seed bed 42 is rod-shaped, plate-shaped or strip-shaped, a hole may be provided in the seed bed and screwed. It is desirable to make a rod-like, plate-like or strip-like seed bed with a mixture of wood flour and resin. As a result of various experiments, it was found that the initial germination rate of seaweed spores was improved by using a mixture of wood flour and resin. When the seed bed 42 is fastened to the artificial reef member with screws (not shown) or the like, it is necessary to use a material that does not easily corrode in order to prevent the screws from falling off due to corrosion. There is also a method of adhering and fixing the end of the seed bed 42 to the artificial reef member with a silicon-based adhesive. In this case, it takes time to solidify the adhesive, but the labor such as screwing can be reduced. In the artificial reef member 40 shown in FIG. 8, the seed bed 42 is attached to each artificial reef member 40, but the artificial reef member 40 shown in FIG. 8 is combined to form a large artificial reef 7 as shown in FIG. In such a case, long string-like seed beds (not shown) are sequentially inserted into the grooves 47 of a number of artificial reef members 40 arranged on a plane, and the claws 49A and 49B provided in the vicinity of the upper surface of the groove portions 47 are used. It may be fixed. Since the long seed beds can be reliably fixed in the grooves 47 of the adjacent artificial reef members 40 by the claws 49A and 49B, the outflow can be prevented even if a large force is applied to the seed beds due to tides or the like. As shown in FIG. 6 (b), the long string-like seed bed is placed in a groove 38A formed when the artificial reef members 30 of the second embodiment are arranged on a plane, and is placed at predetermined intervals. It may be fixed with screws or the like.
[0025]
When the artificial reef member 40 in which seaweed spores are contained in the seed bed 42 is installed in the sea, the seaweed spores contained between the fibers of the seed bed 42 drift into the seawater, and the surface of the artificial reef member 40 It adheres to the groove 6 and germinates. In the groove 6, the water force due to the flow of seawater is relaxed, so that the spores are less likely to flow into the seawater, and the spore implantation rate is relatively high. When the artificial reef member 40 is installed in the sea, the seawater penetrates into the wood powder partially exposed on the surface of the artificial reef member 40 immersed in seawater, and the resin skin layer from the pinhole of the resin skin layer on the surface. Seawater penetrates the wood flour below. As a result, the wood powder in the vicinity of the surface of the artificial reef member 40 expands, the resin skin layer that wrapped the wood powder at the time of molding is broken, and seawater gradually permeates the internal wood powder. In such a state, the artificial reef member 40 becomes a porous organic member suitable for the growth of organisms, and the spores of seaweed coming out of the seed bed 42 are easily attached and spores after the attachment are generated.
[0026]
【The invention's effect】
As described in detail in each of the above embodiments, according to the artificial reef member of the present invention, the surface is uneven and the grooves and the plurality of holes in the random direction are formed in advance. Easily grow with spores attached. In addition, the roots of the grown seaweed extend in each direction through the groove, reach the back of the artificial reef member through the hole, and entangle with the artificial reef member, so that the seaweed is firmly fixed and washed away by tides, etc. It becomes difficult. Seaweed grows and grows by being firmly fixed to the artificial reef member. When seaweed beds are formed by the growth of seaweeds, fish and shellfish start to inhabit the seaweed beds, which has a great effect on the development of marine resources. The artificial reef member of the present invention can be used for seaweed growth in the vicinity of the coast and on revetment walls such as rivers and lakes, and has a wide range of use for environmental regeneration. It is easy to maintain the seaweed seed bed, and the implantation of seaweed spores is promoted, so that the seaweed bed can be grown in a short time. Since the roots sticking out with the growth of seaweed are strong, it is possible to provide a seaweed bed that can withstand water resistance such as waves and tides in each direction. Since the artificial reef member of the present invention can use waste wood or plastic as a raw material, it can be used for industrial waste and contribute to environmental protection. In addition to the formation of seaweed beds, the use of the artificial reef members and artificial reefs is effective not only for the restoration of coral reefs, but also can be effectively used for implantation and aquaculture of seafood and the like.
[Brief description of the drawings]
FIG. 1 is a perspective view of an artificial reef member according to Embodiment 1 of the present invention.
FIG. 2 is a II-II cross-sectional view of the artificial reef member according to Embodiment 1 of the present invention.
FIG. 3 is a perspective view of an artificial reef constituted by the artificial reef member according to the first embodiment of the present invention.
FIG. 4 is a partial cross-sectional perspective view showing a state where seaweed has grown on the artificial reef member according to Embodiment 1 of the present invention;
FIG. 5 (a) is a top view of the artificial reef member according to Embodiment 2 of the present invention.
(B) is Vb-Vb sectional drawing of (a).
FIG. 6 (a) is a perspective view showing a step of connecting an artificial reef member according to Embodiment 2 of the present invention.
(B) is the side view which shows the state which the artificial reef member of Embodiment 2 connected.
FIG. 7 (a) is a bottom view showing another example of the artificial fishing reef member according to Embodiment 2 of the present invention.
(B) Right side view
FIG. 8 is a perspective view of an artificial reef member according to Embodiment 3 of the present invention.
9 is a cross-sectional view taken along line IX-IX in FIG.
10 is a sectional view taken along line XX in FIG.
11 is a sectional view taken along line XI-XI in FIG.
FIG. 12 is a perspective view of a conventional artificial reef member.
[Explanation of symbols]
1, 20, 30, 30A, 40 Artificial fishing reef member
3, 3A, 35 Surface
4 Back side
5 Unevenness
6, 6A, 47 grooves
7 Artificial fishing reef
8 Bracket
9 holes
10 Mounting hole
31 protrusion
32 holes
38 steps
39 Recess
42 seed beds
46 Hook
48 Fixing member
49A, 49B Nail
60 Seaweed
61 roots
