Kochi University Repository

森田, 美佐

MORITA, Misa

A Study of Home Economics Education for "Kajimen" and "Ikumen"

三浦, 要一

ミウラ, ヨウイチ

MIURA, Youichi

Restoration Researach and Design of Castle Architecture

江口, 葉月

石川, 一馬

井上, 光也

加藤, 元海

四万十川上流域における河川環境と底生生物

平成26年3月24日授与　高知大学甲総黒博第11号　中城 満氏学位申請論文博士（学術）高知大

中城, 満

ナカジョウ, ミツル

海洋研究成果の教材化と児童・生徒のメタ認知能力の育成

平成26年3月24日授与　高知大学甲総科博第12号　松浦 由美子氏学位申請論文要約博士（理学）高知大

松浦, 由美子

（博士論文要約） 
博士論文名 ： 乳酸変換に対する固体酸塩基触媒特性 
研究科・専攻名 ： 高知大学大学院総合人間自然科学研究科（博士課程） 応用自然科学専攻 
氏名 ： 松浦 由美子 
学位授与年月日 ： 平成 26 年 3 月 24 日 博士（理学） 
 
概要 
アクリル酸は吸水性ポリマーの原料であり，世界で年間 300 万トンの需要がある[1]．現在，アクリル酸は，石油由
来の化合物であるプロピレンから製造され，高吸水性ポリマー等の原料として幅広く利用されている．しかし，この
反応プロセスは反応制御が容易ではなく, また 2 段階プロセスであることが問題点である．さらに近年，石油枯渇
や地球温暖化が懸念されている．そのため，石油の代替資源とその反応プロセスの開発が求められている．石油
の代替資源として注目されているのが再生可能なバイオマス資源で，アクリル酸は，バイオマス由来化合物であ
る乳酸を一分子脱水することで得られる．乳酸はバイオマス資源から工業的に製造することが可能なため，乳酸
からアクリル酸への選択的変換プロセスの開発が求められている．そこで，本研究ではバイオマス資源からアクリ
ル酸を製造する反応プロセスの開発を目指し，乳酸からアクリル酸へ効率的に変換できる反応プロセスの開発を
行った．  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 1 乳酸の変換反応に対する反応スキーム[2] 
 
 これまでに，固体酸塩基触媒を用いた気相法 (Table 1 Entry 4-7) が超臨界水法 (Table 1 Entry 1-2) 及び固
体酸触媒を用いた気相法 (Table 1 Entry 3) よりも高いアクリル酸収率を示すことが報告されている. しかし，Fig. 
1 に示したアセトアルデヒド, 2, 3-ペンタンジオン，プロピオン酸及びラクチドなどが副生するため，アクリル酸収率
は最大でも 63 %で工業的に十分ではない．乳酸からアクリル酸への選択的変換反応では，固体酸塩基触媒の
酸塩基性度が重要な因子とされるが，既報の固体酸塩基触媒の酸塩基性度は系統立っておらず，アクリル酸生
成と酸塩基性度の関係は明らかにされていない．そこで，固体表面の酸性度－塩基性度に着目して酸塩基触媒
特性を解明し，既報の触媒より高いアクリル酸収率を達成するとともに，触媒の活性点構造の解明を目指した. そ
の結果，Table 1 の Entry 8-10 に示すような高活性固体酸塩基触媒を開発した. 以下に本学位論文の概要を示
す． 
 
 
Table 1 乳酸の変換反応 
 
 
第 2 章 乳酸変換に対するアルカリ金属塩担持触媒の酸塩基触媒特性― 担体，アルカリ金属塩の種類及
びアルカリ金属塩の担持量の影響 
アルカリ金属塩担持触媒は担体にアルカリ金属塩を含浸担持して得られる固体酸塩基両機能性触媒である．
近年，アルカリ金属塩担持固体触媒による乳酸からアクリル酸への変換反応プロセスの開発が盛んに行われて
いるが, 十分なアクリル酸収率は得られていない．アクリル酸生成には触媒の酸塩基性度が重要な因子とされる
が，アクリル酸生成との関係は未解明である. そこで本研究では, 固体酸塩基触媒として担体の種類，アルカリ
金属の種類及び Na 塩担持量を変えて様々なアルカリ金属塩担持固体触媒を調製し，固体酸触媒，固体塩基触
媒及び固体酸塩基触媒の触媒特性を明らかにすることを目指した．その結果，20-30 wt% の NaNO3 を担持した
Entry 触媒 
反応温度  
(ºC) 
転化率 
(%) 
アクリル酸選択率  
(%) 
Ref. 
1 H2SO4 (超臨界水中) 385 74 12 [3] 
2 NaOH (超臨界水中) 385 61 23 [3] 
3 SiO2  300 3.0 6.7 [4] 
4 Na3PO4/SiO2-Al2O3 350 40 25 [5] 
5 NaNO3/SiO2 370 90 29 [6] 
6 KNO3/NaY 325 99 50 [7] 
7 Na2HPO4/NaY 350 82 63 [8] 
8 NaNO3/NaY 350 77 73 This study
9 Ca-P (Ca/P=1.67, (Ca+Na)/P=1.67) 350 92 58 This study
10 Ca-P (Ca/P=1.55, (Ca+Na)/P=1.65) 350 90 87 This study
NaY (Si/Al=2.65) 触媒が既報のどの固体酸塩基触媒よりも高いアクリル酸収率及び選択率を示すことを見出し
た. この触媒は，NaNO3 で NaY の細孔が閉塞しており，さらに，NaY の外表面に NaNO3 が担持していると考えら
れる (Fig. 2 (c))．焼成後に，硝酸イオンが減少していたことから，焼成後の 30 wt% NaNO3/NaY に担持された一
部の NaNO3 は Na2O または NaOH に変化しているものと考えられる (Fig. 2 (d))．これに対し，NaY (Fig. 2 (a)) 及
び 7.8 wt%の NaNO3 を NaY に担持した場合 (Fig. 2 (b))，反応初期に触媒が失活する．これは，生成したコーク
が NaY の細孔を閉塞させたためだと考えられる．また，37 wt% の NaNO3 を担持すると，未同定の副生成物が多
く，アクリル酸選択率は減少した．固体酸触媒は主にアセトアルデヒドを生成し，固体塩基触媒では乳酸の転化
率が低く，未同定の副生成物が多かった． 
 
 
 
 
 
 
  
     (a)              (b)             (c)              (d) 
  
Fig. 2 推定される NaY 及び NaNO3 / NaY の構造   
 
(a) NaY，(b) 7.8 wt% NaNO3 / NaY，(c) 20-37 wt% NaNO3 / NaY， 
(d)焼成後の 30 wt% NaNO3 / NaY  
 
 
第 3 章 乳酸変換に対するアパタイト触媒の酸塩基触媒特性―構成元素, M/P 比及びアパタイト触媒に 
含有するアルカリ金属の影響 
ハイドロキシアパタイト (Ca10(PO4)6(OH)2) は六方晶系の化合物 (Fig. 3) で，歯や骨の主成分である．また，
有機物との親和性が高く，熱安定性にも優れている．ハイドロキシアパタイトはフレキシブルな結晶構造を有する
ため，構成元素を様々な元素で置換することが可能で，その結果，酸塩基触媒特性が変化する[9]．ハイドロキシ
アパタイトは非化学量論組成をとることができ，Ca/P = 1.5-1.8 程度のものが知られている[10]．Ca/P < 1.67 のもの
をカルシウム欠損型アパタイトと呼び，Ca2+, OH-イオンの欠損と H+イオンと H2O の導入によって説明される 
(Ca10-n(HPO4)n(PO4)6-n(OH)2-n(H2O)n)．Ca 欠損による空孔，HPO4 基に由来する酸点，構造水あるいは吸着水に
由来する塩基点が新たに発現し，触媒特性が変化すると考えられる[11]．一方，Ca/P>1.67 のものをカルシウムリ
ッチ型アパタイトと呼び，PO43-イオンの欠損[10]や原料の Ca 化学種の残存[12]，CO32-イオンによる PO43-イオンの
置換[13]など様々な説がとられているが，Ca/P 比増加の原因については明らかになっていない．このように，ハイ
(  ) Na+ 
(  ) NaNO3 
(  ) Na2O または
NaOH 
ドロキシアパタイトの Ca/P 比を変えることで酸塩基触媒特性が変化する．  
乳酸からアクリル酸への脱水反応では触媒の酸塩基性度が重要な因子とされるが，アクリル酸生成との関係性
は未解明である．そこで，本研究では, ハイドロキシアパタイトの構成元素及びアパタイト化合物 
(M10(PO4)6(OH)2: M=Ca, Sr, Pb, ZO4=PO4, VO4)(以下, M-Z)の M/P (M=Ca, Sr) 比を変えることでアパタイト化合
物の酸塩基性度とアクリル酸生成との関係を明らかにし，従来のアクリル酸収率を達成することを目指した．その
結果，一部の Ca イオンと微量の Na+イオンが部分置換した Ca-P (Ca/P=1.55, (Ca+Na)/P=1.65))のアクリル酸収率
78 C-%, 選択率は 87 C-%を示した．これは，本研究で見出した NaNO3 担持ゼオライト触媒を含めた既報のどの
触媒よりも高いアクリル酸収率及び選択率を示した． 
 
 
 
 
 
 
 
 
 
 
                            Fig. 3 Ca10(PO4)6(OH)2 の構造 
 
 
第 4 章 乳酸変換に対する活性点構造の解明 
乳酸変換における主な反応生成物はアクリル酸，プロピオン酸，2,3-ペンタンジオン，アセトアルデヒド，アセトー
ル及びラクチドであった．これまでに，乳酸からアクリル酸への脱水反応に対し，Na3H2P3O10 触媒の POH と乳酸
の OH 基が脱水縮合することでアクリル酸が生成する反応メカニズムが提案されている．一方，乳酸から 2, 3-ペン
タンジオンへ縮合反応に対し，リン酸塩触媒と乳酸がアシルリン酸を形成し，クライゼン縮合，脱炭酸を経て, 2, 3
ペンタンジオンが生成する反応メカニズムが提案されている．このように，生成物選択性は，触媒の活性点構造
に起因すると考えられるが，活性点構造は，まだ未解明である．  
 本研究から乳酸からアクリル酸への脱水反応に対する活性点構造は，吸着サイトがお互いに離れており，アル
カリ金属イオンやアルカリ土類金属イオン，特に Na+イオンが触媒の表面付近に存在するような構造だと考えられ
る． 
 
 
Ca2+ P O OH
参考文献 
[1] H. Danner, R. Braun, Chem. Soc. Rev., 28 (1999) 395. 
[2] D. C. Wadley, M. S. Tam, P. B. Kokitkar, J. E. Jackson, D. J. Miller, J.Catal., 165 (1997) 162. 
[3] W. S. Mok, M. J. Antal, J. Org. Chem. 54 (1989) 4596. 
[4] M. S. Tam et al., Ind. Eng. Chem. Res., 37 (1998) 2360. 
[5] G. C. Gunter, D. J. Miller, J. E. Jackson, J. Catal. 148 (1994) 252. 
[6] D. C. Wadley, M. S. Tam, P. B. Kokitkar, J. E. Jackson, D. J. Miller, J. Catal. 165 (1997) 162. 
[7] P. Sun, D. Yu, K. Fu, M. Gu, Y. Wang, H. Huang, H. Ying, Catal. Commun. 10 (2009) 1345. 
[8] J. Zhang, Y. Zhao, M. Pan, X. Feng, W. Ji, C. T. Au, ACS Catal. 1 (2011) 32. 
[9] J.C. Elliott, Structure and chemistry of the apatites and other calcium orthophosphates, Stud. Inorg. Chem., vol. 
18, Amsterdam, Elsevier, 1994. 
[10] F. Okada, M. Yuizumi, H. Sakane, T. Hatsushika, T. Suzuki, J. Soc. Inorg. Mater. Japan, 7 (2000) 185. 
[11] 土田敬之，佐久間周治，触媒，49 (2007) 238. 
[12] 川村資三，化学技術誌 MOL, 321 (1989) 92. 
[13] 金澤孝文，梅垣高士，門間英毅，セラミックス，10 (1975) 461. 
 
 
 


乳酸変換に対する固体酸塩基触媒特性

平成26年3月24日授与　高知大学甲総科博第11号　岡本 信行氏学位申請論文要約博士（理学）高知大

岡本, 信行

博士論文 
「北西太平洋域の海山の地形・地質と鉄・マンガンクラストの地域分布の多様性」 
 
平成 26 年 3 月 
 
高知大学大学院総合人間自然科学研究科応用自然科学専攻 
岡本 信行 
 
要 約 
 
鉄・マンガンクラスト (以下、「クラスト」という) は、遠洋の海山や海嶺に広
く分布し、自動車産業や情報業において将来需要拡大が見込まれる Ni、Co、Pt、レ
アアースなどのレアメタルを含有する。北西太平洋域は、特にクラストの資源ポテ
ンシャルが高い海域であり、1980 年代以降、ドイツ、米国、ロシア、韓国、日本、
中国などによる調査が行われてきた。特に、 我が国は、マーシャル諸島共和国 (RMI) 
やミクロネシア連邦 (FSM) 等の排他的経済水域 (EEZ) において、南太平洋諸国へ
の技術協力の一環として、クラストの資源量把握を目的とした調査航海を実施し、
膨大な地形・地質データが蓄積されたが、未だに研究面での考察が不十分のまま残
されている。 
一方、地球科学研究の立場からは，クラストの成長は海山の地形・地質・形成史
と密接な関係があるとされるものの、広域～微細スケールまで非常に高い多様性の
原因解明や、クラストの成長を規制する要因分析や科学的実態解明が正確になされ
ているとはいえず、従って，将来の有望エリア選定のための、地質・地形情報に基
づくクライテリア (科学的基準) の設定が不充分である。 
 
本研究では、上記の海域の膨大な調査結果を総括した上で、まず、当海域に分布
する多数の海山から代表的な 27 海山を選定し、海山規模、頂部水深、地質、海山の
形成年代等とクラスト層厚との関連を比較検討した。 
この結果、クラストの成長と海山の地形・地質との関係について、海山の山頂水
深や海山山頂部に分布する遠洋性堆積物の産状，層厚に関しては、明瞭な関係を有
することは認められなかったが、海山を構成する火山岩や石灰岩の形成年代や地形
的特徴との関連をつかむことができた。 
クラスト層厚と基盤岩である火山岩の年代との関係において、クラスト層厚は、
23mm～190mm と幅広いレンジであり、その生成年代も 5.1Ma～82Ma と幅広いもの
の、形成年代が古い海山ほどクラスト層厚が厚い傾向が顕著に見られる。また、礁
性石灰岩中には厚歯二枚貝などの大型化石が観察され、それらの鑑定結果から礁性
石灰岩の生成年代レンジが推定され、海山の沈降が開始した年代の根拠となり、沈
降開始年代が古いほど、すなわち海面下にいる時間が長いほどクラスト層厚が厚い
ことが読み取れ、長期間にわたって沈降が継続した海山ほどクラストポテンシャル
が高いことが分かる。 
 
また、選定した 27 海山を 4 つの形態タイプ (大規模平頂海山、小規模平頂海山、
円錐型海山、海嶺型海山) に分類し、それぞれ海山の形成史を推定し、クラストの
成長との関連を検討した。この際に、平頂海山は、平頂部の面積から 2 つに区分し、
1,000 km2 を超えるものを「大規模」、それ以下のものを「小規模」に細分化した。
27 海山の分類結果は、大規模平頂海山は 8 海山、小規模平頂海山は 13 海山、円錐
状海山は 5 海山、及びその他 (海嶺型) は 1 海山である。 
これらの結果を踏まえて、海山の形態タイプ毎に、火山岩の放射年代及び化石年
代 (報告値) や音波探査記録などに基づき、山体形成から浸食・沈降、遠洋性堆積
作用に至る海山の進化・環境の変化とクラスト成長についてのモデルを提案した。 
大規模平頂海山については、白亜紀中期頃の 100Ma 前後に、巨大な火山噴火によ
って、大規模な火山島が形成され、その結果、火山の山頂は海面上に現れ、波浪に
よって火山の山頂は平坦面に浸食され、礁が形成された。石灰岩中の化石年代鑑定
の結果、沈降が始まったのは、60 Ma ～80 Ma より古いと推定される。ミクロネシ
ア連邦のMC10海山のクラスト試料を使ったBe10/Be9 を用いたクラストの成長速度
が測定（4.3mm/m.y.）されており、そのデータを利用して、クラストの成長開始を
推定すると 20 Ma～40 Ma となる．その間，現在までにクラストは厚さ 75mm～155 
mm に成長したことになる。一般に、大規模平頂海山の上部斜面は急崖となってい
るが、これは恐らくリン酸塩化された石灰岩の硬質な構造を反映していると思われ、
長期間安定な地質環境はクラストの連続的な沈殿と成長を促したと考えられる。 
次に、小規模平頂海山は 50Ma 前後に起こった火山活動によって形成されたもの
が多い。頂部の一部が海面上に現れたが、その後の風化・浸食によって頂部が平坦
化し、40 Ma～50Ma に水没した。クラストの成長は、前述の成長速度を用いると
15 Ma～30 Ma に始まり、55 mm～140mm 厚に達した。狭い頂部の基盤岩のいくつ
かの部分は、硬い石灰岩が分布するものの、厚いクラストの分布域は一般に狭い。 
円錐型海山は、海底の火山噴火によって形成されたが、海面における礁の形成は
ほとんどなかった。新鮮な火山岩は、強い風化にさらされ、海山の急激な沈降又は
浸食などによる構造運動によって、海山が不安定になり、大規模崩壊や地形の変形
を加速させた可能性がある。従って、このタイプは、頻繁な大規模崩壊が続き、長
期的に連続的なクラスト成長を維持することができなかったと考えられる。 
海嶺型については、ミクロネシア連邦の EEZ に属する１海山であり、当該海山の
形成は約 70Ma に起こったものと推定される。このタイプは、大規模崩壊の痕跡を
有していることが地形・地質調査から分かっている。このため、クラストの厚さは
最大 20cm のものまで認められたが、分布域は散在するのみでポテンシャルは大き
くはないと考えられる。 
以上、4 つの形態タイプについて検討した結果、大規模平頂海山は、小規模平頂
海山と比べて、山体形成年代は明らかに古く、またその後の沈降に引き続き、
75-155mm 程度の厚いクラストが成長する傾向が強いことが判明した。円錐型海山
は海面下で火山形成が起こり、礁を形成せずに沈降したため、火山岩から成る山体
は風化による崩壊が起こりやすく、クラストの発達が阻害される可能性が高いと判
断された。海嶺型は 1 か所のみで、クラスト層厚が厚いものの、複雑な海山形成史
をたどった可能性が高いと指摘した。 
 
以上の考察に基づくと、広域的スケールの資源量に関して有望な海山は、1)大規
模であること、2) 安定した基盤を維持するためには強固な石灰岩に広く覆われた平
頂海山が望ましい、3) 堆積速度が小さな堆積環境、との選定基準を導いた。 
 
次に、一海山における詳細スケールの地形変化とクラスト形成の関係について検
討した。ミクロネシア連邦の EEZ に分布する海嶺型海山をモデルとし、まず深海
TV カメラとドレッジサンプリングに基づいて、本海山の平頂部から斜面にかけて
海底の露岩状況を把握した。その結果、露岩域であっても、地形的条件によって、
クラストが厚く分布するエリア (尾根部) と非分布域 (谷部) が存在することが判
明し、クラストの平均厚さの差は 10 倍近いことが確認された。海山の詳細地形に注
目すると、谷地形が発達する海山は、火山体形成後、頻繁な山体崩壊や海底地滑り
等が発生したことにより、クラスト資源量が低下する可能性を指摘した。 
 
以上、広域的～詳細スケールの検討結果から、クラストの有望海域を選定するた
めの地質学的条件を把握することができた。 
すなわち、広域スケールでの有望海山選定に関わる地質学的要因としては、 
① 十分な沈降期間を持つ大きな山体であること 
② 頻繁な山体崩壊や海底風化の少ない地質学的に安定した基盤であること 
③ 海洋の炭酸塩の大量かつ迅速な堆積作用を防ぐ要素があること 
の 3 条件に集約される。このことから、4 つの形態タイプの海山の中では、大規模
平頂海山タイプが、クラストの発達に有望な海山であると結論付けた。 
 一方、詳細スケールの分布多様性に関わる地質学的要因として、海山単位で見た
場合、反射音圧データはクラストが分布する露岩域の抽出に有効な手段であるもの
の、露岩域であっても海山の尾根部と谷部ではクラストの発達には大きな違いがあ
ることが明らかとなった。つまり、クラストの地域的生成過程を通じて基盤岩体が
地質学的に安定であることが重要な要件であることが明らかになった。 
 
最後に、将来の研究調査の課題として、さらなる高分解能の地形・地質データ取
得や掘削データなどの充実が必要であり、そのためには、地震探査や深部掘削によ
る海山の内部構造の把握、石灰岩の解析による沈降年代やプロセスの把握、火山岩
の放射年代による海山形成年代の詳細、クラストのより一般的，広範囲の年代測定
手法の開発等、を進めるべきであるとした。また、詳細スケールでの検討では、よ
り多くの海山で検証する必要であることを課題に添えた。 
 
以上のとおり，クラストの広域的～詳細スケールの分布産状と地形・地質環境と
の比較検討に関する事例研究の結果、クラストの有望海域を選定するための地質学
的パラメータを示すことができ、将来のクラストの探査指針・資源量評価手法開発
に大きく貢献すると思われる。 
 


北西太平洋域の海山の地形・地質と鉄・マンガンクラストの地域分布の多様性

Lee, Nyanti

Jongkar, Grinang

James, Bali

Norhadi, Ismail

53
Kuroshio Science 8-1, 53-57, 2014
*Corresponding author: e-mail lnyanti@frst.unimas.my; nyantilee@gmail.com
Fish Fauna and Fisheries in the Coastal Waters of Similajau, 
Bintulu, Sarawak, Malaysia
Lee Nyanti1*, Jongkar Grinang2, James Bali3 and Norhadi Ismail1
1 Department of Aquatic Science, Faculty of Resource Science and Technology, 
  Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
2 Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, 
  94300 Kota Samarahan, Sarawak, Malaysia
3 Sarawak Forestry Corporation, Lot 218, KCLD Jalan Tapang, Kota Sentosa, 
  93250 Kuching, Sarawak, Malaysia
Abstract
The coastal waters of Similajau serve as traditional fishing grounds for fishermen from Kuala Nyalau 
and for those from as far away as Bintulu. This study on fish fauna and fisheries in the area was car-
ried out before the construction of Samalaju Industrial Park and Samalaju Port. It was aimed at docu-
menting fish fauna composition and fisheries in the area so that data collected could provide future 
baseline information. Subjects for the study were collected using monofilament gill nets of three 
different mesh sizes and monofilament drift nets. A total 1,336 fish comprising 42 families and 120 
species were caught from the area. The five dominant families were Carangidae (17.8%), Engraulidae 
(16.2%), Pristigasteridae (10.7%), Ariidae (8.3%) and Synodontidae (7.8%). The five dominant spe-
cies collected were Parastromateus niger (13.1%), Harpodon nehereus (7.6%), Setipinna taty (4.3%), 
Setipinna tenuifilis (4.2%), and Ilisha elongate (3.9%). Fishing activities were carried out within 
10 km of the coastline using a small size fiberglass boat powered by a 15 to 40 hp engine. Fishing 
methods employed included gill nets, drift nets, hooks and lines, long lines, trap nets, cast nets and 
push nets.  The fishing season is from March to September, when the sea is calmer, and peaks in June 
and July. The quantity of fish caught ranged from 50 to 200 kg per fishing trip. 
Key words: coastal fisheries, length-weight, Samalaju Port, Kuala Nyalau
Introduction
In Malaysia, marine fisheries contribute significantly 
to the national economy as they are an important source 
of protein, employment and foreign exchange. Landings 
from marine fisheries sector increased from 570,754 
mt in 1985 to 1,373,105 mt valued at RM6.939 billion 
in 2011. This sector provided employment to 134,110 
fishermen and contributed to about 1.1% to the gross 
domestic product of the nation in 2011 (DOF, 2011).
In Sarawak, landings from marine fisheries sector 
were 119,459 mt in 2011, and it provided employment 
for 16,000 people (DOF, 2011). However, the landings 
from marine fisheries started to decline from 2005.
The coastal waters of Similajau in Bintulu, Sarawak 
have always been traditional fishing grounds for fish-
ermen from Kuala Nyalau. With  development taking 
place along the coastal zone, especially the demarca-
tion of Samalaju Industrial Park and the construction of 
Samalaju Port within the area, potential changes in fish 
fauna and fisheries in the area are expected to occur in 
the next few years when the industrial park and the port 
start operation. This study on fish fauna and fisheries 
was carried out before the construction of the industrial 
park and port. It was aimed at documenting the fish 
fauna composition and the diversity and status of fish-
eries in the coastal waters of Similajau so that the results 
obtained could act as baseline data for future studies.
Materials and Methods
Study Sites and Fish Fauna Sampling
There is no official boundary of the coastal waters of 
Similajau. Nonetheless, in this study, the coastal waters 
of Similajau were identified as the aquatic environment 
stretching from the mouth of the Simalajau river in the 
south to the Cape of Payong in the north. It is a straight 
coastal marine environment with a few small bays and 
54
Fish Fauna and Fisheries in the Coastal Waters of Similajau, Bintulu, Sarawak, Malaysia
capes, whereas brackish water only occurs at the mouths 
of the Simalajau and Nyalau rivers. The seabed is pre-
dominantly sand and mud with patches of shoals and 
reefs. During the study, the beaches were sandy with 
rocky features at the capes, adjoining intact forests on 
the land. The area is occupied by one community, which 
lives at the mouth of the Nyalau river.
Sampling of fish fauna was carried out at 15 stations 
in March, June, September, October and November 2008 
and March and April 2011 (Figure 1). Subjects for the 
study were collected at all stations (expect Station 11) 
using monofilament gill nets of three different mesh sizes 
of 2.5 cm, 5.0 cm, 7.5 cm with length of about 310 m 
each. At station 11, a monofilament drift net with mesh 
size of 12.5 cm and length of 2.7 km was used. At station 
three, an additional fishing method consisting of hook 
and line was used to catch freshwater prawns. Each type 
of fishing method was employed in a similar manner at 
all the stations (except station 11). When gill nets were 
employed, they were placed at each station for a period 
of four hours from 0700 to 1100 hr. The drift net was 
placed at 0400 hr and lifted at 0630 hr. Fishing for fresh-
water prawns using hooks and lines and baited hooks 
using earthworms were carried out by six persons from 
two different boats. 
Fish species were mostly identified in situ. Only 
specimens that could not be identified in the field were 
preserved in 10% formalin and later transferred to 70% 
ethanol for identification in the laboratory. Fish were 
identified based on Masuda et al. (1984), Kottelat et al. 
(1993), Mansor et al. (1998) and Lim & Gambang (2009). 
The total length and weight of every fish was measured 
with a fish measuring board and portable electronic bal-
ance (Shimadzu ELB-600) respectively.
Additional data on the fisheries at Kuala Nyalau 
Village were obtained through open-ended interviewers 
with full time fishermen in the study area. 
Diversity Indexes 
At each station, the diversity (H), richness (D) and 
evenness (J) indices were calculated following Shannon 
and Weaver (1963), Margalef (1968) and Pielou (1966), 
respectively.
Results
Fish Composition
A total 1,336 individuals comprising 42 fami-
lies, 73 genera and 120 species were caught from the 
study area. The ten dominant families recorded were 
Carangidae comprising 17.8% of the total number of 
individuals caught, followed by Engraulidae (16.2%), 
Pristigasteridae (10.7%), Ariidae (8.3%), Synodontidae 
(7.8%), Lutjanidae (3.9%), Serranidae (3.5%), Sciaenidae 
(3.4%), Stromateidae (3.3%) and Kurtidae (3.1%)
(Figure 2). The dominant species was Parastromateus 
niger comprising 13.1% of the total number of indi-
viduals caught, followed by Harpodon nehereus (7.6%), 
Setipinna taty (4.3%), Setipinna tenuifilis (4.2%), Ilisha 
elongata (3.9%), Coilia macrognathus (3.8%), Kurtus 
indicus (3.1%), Pampus argenteus (2.7%), Ilisha mega-
loptera (2.4%) and Lutjanus vitta (2.2%)(Figure 3).
The diversity index was highest at station ST5, 
Figure 1. Location of the fish fauna sampling stations at the 
coastal waters of Similajau, Bintulu.
Table 1. The values of diversity, evenness and richness indices for each station.
Station H D J
ST1 1.12 10.54 0.91
ST2 1.14 10.28 0.92
ST3 1.27 11.56 0.93
ST4 0.71 5.70 0.71
ST5 1.29 11.67 0.96
ST6 1.01 11.00 0.69
ST7 1.25 12.03 0.96
ST8 0.99 6.38 0.91
Station H D J
ST9 1.21 11.86 0.84
ST10 1.13 8.96 0.90
ST11 0.35 3.00 0.39
ST12 0.86 5.22 0.90
ST13 0.98 5.74 0.98
ST14 0.99 7.97 0.84
ST15 0.96 6.07 0.89
55
Lee Nyanti, Jongkar Grinang, James Bali and Norhadi Ismail
showed the most richness at station ST7, and the highest 
similarity at stations ST5 and ST7. The diversity, rich-
ness and similarity indices were lowest at station ST11 
(Table 1).
Fisheries
There were 107 fishermen and five fish dealers in 
Kuala Nyalau. Fishermen used fiberglass boats with 
lengths of about 9 m powered by 15 to 40 hp engines. 
Fishing activities were mainly carried out within 10 km 
of the coastline except during certain fishing seasons 
(e.g., for black pomfret Parastromatesu niger) where 
fishermen would go up to 15 km offshore or 40 km out 
when fishing at reefs and rough ground. The popular 
fishing grounds included the coastal area from Payong 
cape to Likau shoals and as far as a few kilometers north 
of Pematang Payung (Figure 1).
The fishing season was during the months of March 
to September, when the sea was calmer, and peaked in 
June and July. Fishing equipment used included gill nets, 
drift nets, hooks and lines, long lines, trap nets for reef 
fishes and mangrove crabs, and  push nets. The quantity 
of fish caught varied greatly, ranging from 50 kg to over 
200 kg. 
During Acetes spp. (locally known as bubuk) season 
from February to June and peaking in March and April, 
push nets and purse seine nets with a small mesh size 
were used. A push net operated manually could catch 
30 kg per fishing trip of four hours, whereas a push net 
operated using an outboard powered engine could catch 
up to 200 kg per fishing trip. A purse seiner could catch 
as much as 400 kg per fishing trip. The Similajau river 
Parastromateus 
niger, 27%
Harpodon 
nehereus, 16%
Setipinna 
taty, 9%
Setipinna 
tenuiﬁlis, 9%
Ilisha 
elongata, 
8%
Coilia 
macrognathus, 
8%
Kurtus 
indicus, 7%
Pampus 
argenteus, 6%
Ilisha 
megaloptera, 
5%
Lutjanus vitta, 
5%
 
Figure 3. The ten dominant species caught in the coastal waters of Similajau, Bintulu.
Figure 2. The ten dominant families caught in the coastal waters of Similajau, Bintulu.
56
Fish Fauna and Fisheries in the Coastal Waters of Similajau, Bintulu, Sarawak, Malaysia
was also a popular fishing area for the fishermen from 
the Kuala Nyalau village, especially during the period 
of rough seas. The normal catch per fishing trip was 
approximately 20 to 30 kg of fish. The most commonly 
caught species were sea catfish from the family Ariidae 
(Arius spp.) and made up  about 70 percent of the total 
catch.
Discussion
The species of fish prevalent in the study area were 
typical of the fish species reported elsewhere in coastal 
areas of Sarawak (Nyanti & Gambang, 2010). The sizes 
of the fish caught were also similar to those reported for 
the Semariang mangrove area by Nyanti et al. (2012a) 
and for the area of Lutong river (Nyanti et al., 2012b).
Construction activity for the Samalaju Industrial 
Park and Samalaju Port as well as operation of these 
facilities could affect fish and fishing activities in the 
area. The major effects will likely be due to the poten-
tial significant increase in silt and total suspended solids 
added to the nearby coastal waters especially during 
dredging, disposing of dredged sediments to the spoil 
ground and piling works related to port construction.
Marine fish landings in Bintulu have been decreasing 
since 2004. In 2009, the landing had decreased by 35 
percent compared with the 2003 landings (DOF, 2008). 
This scenario is also reported for other areas in Malaysia, 
where the coastal waters are overfished as large numbers 
of fishers exploit fisheries resources in the area. This has 
led to changes where small and low-values fish species 
dominate the landings rather than high-value species.
Fish at all life stages are sensitive to increased 
levels of suspended sediment. However, juvenile and 
adult fish are more resilient to high concentrations 
of suspended sediment than the eggs or larvae stage 
(Newcombe, 1994). Fish populations may be affected 
by the presence of a high amount of suspended solids 
in the water, resulting in clogging and abrading of gill 
rakers (Cordone and Kelley, 1961) and stress and sup-
pression of the immune system leading to increased sus-
ceptibility to disease and osmotic dysfunction (Redding 
et al., 1987). Growth of fish could be impaired due to 
excess suspended sediment as it could reduce the quality 
of light, thereby reducing fish ability to see and secure 
food (Singler et al., 1984). A significant reduction in 
fish growth was reported in concentrations of suspended 
sediment ranging from 100 to 1000 mg/l (Canadian 
Environmental Quality Guidelines, 2002).
An increase in shipping will cause a general increase 
in background noise (Popper and Hastings, 2008) and 
depending on the intensity, the response to sounds might 
range from no overt change in behavior to exhibiting a 
mild awareness of the sound or a startle response (Wardle 
et al. 2001) to small temporary movements for the dura-
tion of the sound to larger movements that might dis-
place fish from their normal locations (Slotte et al. 2004) 
for short or long periods of time. 
Although fish mortality is not likely to occur in 
open sea water in areas near Similajau as fish are highly 
mobile and are able to respond quickly to changes in 
their physical environment (Russell et al., 1978), the 
factors noted above are likely to create an avoidance 
response from the fish population where migratory or 
sporadic visitors will avoid the area (Anderson et al., 
1996) leading to a smaller population of fish coming 
to the area and therefore, less fish being caught by the 
fishermen. In addition, the movement of marine traffic 
will cause inconvenience to the fishermen. Therefore, the 
operation of Samalaju Industrial Park and Samalaju Port 
will be likely to affect fishing activities and the fish catch 
in the area.
Acknowledgments 
We acknowledge the support of the Faculty of 
Resource Science and Technology, Universiti Malaysia 
Sarawak (UNIMAS) for providing the equipment 
and facilities to carry out this research. We thank the 
Headman and villages of Kuala Nyalau and especially 
Mr and Mrs Jamal and Mr Affandi for their support and 
warm friendship. We also thank Mr Mustafa Kamal @ 
Harris, Mr Richard Toh and Mr Amin Mangi for field 
assistance. 
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Malaysia. 401 pp.
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2012a. Status and threats to fish diversity and 
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1027.


Fish Fauna and Fisheries in the Coastal Waters of Similajau, Bintulu, Sarawak, Malaysia

Chai Fung Pui

Lesley Maurice Bilung

Nur Bainun Mohd Zin

Nurulhuda Najihah Binti Zainal Abidin

Micky, Vincentl

Kasing, Apun

59
Risk of Acquiring Vibrio parahaemolyticus in Water and Shrimp 
from an Aquaculture Farm
Chai Fung Pui1, Lesley Maurice Bilung1*, Nur Bainun Mohd Zin1,  
Nurulhuda Najihah Binti Zainal Abidin1, Micky Vincent1, Kasing Apun1
1  Department of Molecular Biology, Faculty of Resource Science and Technology, Universiti 
Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia.
Abstract
Vibrio parahaemolyticus is an important foodborne pathogen causing significant economic problems 
within the aquaculture industry worldwide. This study was conducted to determine the occurrence and 
concentration of V. parahaemolyticus in water and shrimp from aquaculture farms. The relationship 
between the concentration of V. parahaemolyticus in ponds and environmental parameters was also 
studied. A total of 264 water samples and 27 shrimp samples from a selected aquaculture farm were 
examined using the most probable number-polymerase chain reaction (MPN-PCR) method, a method 
that incorporates both the count and detection of toxR gene. The correlation between the concentration 
of V. parahaemolyticus in both types of the samples and environmental parameters (temperature, pH 
and salinity) was analyzed statistically by the paired T-test. Based on the results, 132 water samples 
(50%) and 11 shrimp samples (41%) were toxR positive. The concentration of V. parahaemolyticus 
in all the water and shrimp samples using MPN method was found to be more than 1,100 MPN/g. 
The environmental parameters examined were not significantly correlated with the concentration of 
V. parahaemolyticus in both types of samples. The results concluded that there was occurrence of V. 
parahaemolyticus in the aquaculture farm. Therefore, this study highlighted the potential risk of infec-
tion by V. parahaemolyticus from an aquaculture farm to humans. The findings obtained from this 
study could act as  baseline data for the risk assessment of V. parahaemolyticus in water and shrimp 
samples from aquaculture farms. This will further provide useful surveillance data for relevant author-
ities.
Key words: Aquaculture, Shrimp, Water, MPN-PCR, Vibrio parahaemolyticus
*Corresponding author: Tel: +6-019-8907055 / e-mail address: mblesley@frst.unimas.my
Kuroshio Science 8-1, 59-62, 2014
1. Introduction
The gram-negative halophilic Vibrio parahaemo-
lyticus is usually found in tropical and temperate coastal 
waters, as well as in shrimp aquaculture (Norma et al., 
2009). It normally causes gastroenteritis with nausea, 
acute watery diarrhea and abdominal cramp (Gopal et 
al., 2005). Serious infection includes septicemia that 
threatens the life of immunodeficient groups and pro-
longed steroid users (Reham and Amani, 2012). As it 
is one of the leading causes of foodborne outbreaks 
in Asian countries including Malaysia (Tunung et al., 
2010), it triggered our interest as an important subject 
for investigation. In Malaysia, the shrimp aquaculture 
industry has been growing steadily due to government 
incentives, active participation from farmers and a con-
sistent good market price (Hashim and Kathamuthu, 
2005). Nevertheless, vibriosis had resulted in mortality 
and serious economic loss to Malaysia in recent years 
(FAO, 2012). 
As a consequence of increasing outbreaks by V. 
parahaemolyticus, numerous rapid methods for the 
detection and enumeration of this pathogen have been 
implemented (Blanco-Abad et al., 2009). Molecular 
approach targeting certain genes such as toxin operon 
(toxR) gene has been reported by other researchers 
such as Zulkifli et al. (2009) and Gavilan et al. (2013). 
According to Borowsky et al. (2007), the quantification 
of microorganism present in the samples is important 
for assessing the risk to consumers. Recent studies by 
Ponniah et al. (2010) and Tunung et al. (2010) indicated 
that the most probable number-polymerase chain reac-
tion (MPN-PCR) method can be used for both the quali-
tative and quantitative analysis of V. parahaemolyticus. 
This method also allows the simultaneous detection of V. 
parahaemolyticus in MPN tube and it is more sensitive 
60
Risk of Acquiring Vibrio parahaemolyticus in Water and Shrimp from an Aquaculture Farm
than the conventional culturing method (Nordstrom et 
al., 2007). Martin et al. (2004) stated that the MPN-PCR 
method enables the completion of enumeration within 
two days. 
The main objective of this study was to determine 
the occurrence and concentration of V. parahaemolyticus 
in water and shrimp samples from an aquaculture farm 
using the MPN-PCR method. In addition, the study 
aimed to investigate the relationship between the concen-
tration of V. parahaemolyticus in the ponds and environ-
mental parameters, namely temperature, pH and salinity. 
This study will give an insight on the current risk of V. 
parahaemolyticus from the aquaculture environment in 
Sarawak, which is useful in helping to control the food-
borne outbreak. 
2.  The occurrence and concentration of Vibrio 
parahaemolyticus
A total of 264 water samples and 27 shrimp samples 
were collected from two ponds, designated as Pond A 
and Pond B from a selected aquaculture farm in Sarawak. 
During each sampling trip, the environmental parameters 
namely temperature, pH and salinity were measured 
using a thermometer (G H Zeal ASTM), a pH meter 
(pH510, Eutech Instrument) and a salinity refractometer 
(Hisamatsu Atago S/Mill), respectively. All the samples 
were pre-enriched in Alkaline Peptone Water (APW) 
with pH 8.5-8.6 and 1-2 %(w/v) of NaCl (Harwood et 
al., 2004). They were subjected to the three-tube MPN 
method. After incubation at 37 °C for 18 h, we found out 
that all the MPN tubes were turbid with a concentration 
of more than 1,100 MPN/g, indicating the occurrence of 
microorganisms in all the samples. They were then sub-
jected to microbial plate count and species specific PCR 
analysis. The mean concentration of V. parahaemolyticus 
from Pond A and Pond B was 5.9 x 108 CFU/ml and 1.3 
x 109 CFU/ml, respectively. The results analyzed using 
the paired T-test indicated that they were not signifi-
cantly different (P>0.700, p<0.05). 
DNA was extracted from the turbid MPN tubes 
using the boil cell method (Vengadesh et al., 2012). 
Species specific PCR was carried out to detect toxR 
gene with amplicon at 368 bp (Kim et al., 1999). Fig. 1 
showed the gel images obtained from the specific PCR 
for water and shrimp samples. Out of the 264 water 
samples examined, 132 samples (50%) were toxR posi-
tive. On the other hand, 11 positive samples (41%) were 
detected from the total of 27 shrimp samples. The occur-
rence of V. parahaemolyticus detected using PCR on 
water and shrimp samples from two different ponds was 
summarized in Table 1. Our results were consistent with 
the reports by previous studies where the occurrence of 
V. parahaemolyticus in water samples was about 50% 
(Sujeewa et al., 2009) and ranged from 2.6 to 80% for 
shrimp samples (Zulkifli et al., 2009; Merwad et al., 
2011). In brief, the turbidity in MPN tubes is an indica-
Fig. 1. Representative amplification of toxR gene for the identification of V. parahaemolyticus at 368 bp. 
Lane M shows the 100 bp DNA ladder, (1) positive control, (2) to (6) representative positive water sam-
ples, (7) to (10) representative positive shrimp samples and (11) negative control.
Table 1. Occurrence of V. parahaemolyticus in water and 
shrimp samples from two different ponds in an aquaculture 
farm.
Sample Pond A Pond BNo.a %b No.a %b
Water 72/141 51 60/123 49
Shrimp 8/15 53 3/12 25
a Number of positive samples/number of samples examined. 
b  Occurence (in %) of positive samples among the samples 
examined.
61
Chai Fung Pui, Lesley Maurice Bilung, Nur Bainun Mohd Zin et al.
tion of the presence of a wide broad of microorganisms 
whereas PCR conducted in this study was specific to V. 
parahaemolyticus.
3.  The relationship between concentration of 
Vibrio parahaemolyticus and environmental 
parameters
There was no significant difference between the 
concentration of V. parahaemolyticus in the samples and 
temperature as the study area has little variation in envi-
ronmental temperature due to controlled temperature in 
both ponds. This was in agreement with the study carried 
out by Renata et al. (2010) which reported that there was 
no correlation between temperature and MPN value in 
the areas with modest temperature. On the other hand, it 
is a fact that Vibrio grows best in temperatures between 
17 and 35 °C (Cervino et al., 2004). Zulkifli et al. (2009) 
also mentioned that a high marine temperature between 
25 and 35 °C resulted in the distribution of V. parahae-
molyticus all year round. As a result, it could be inferred 
that in this study, the occurrence of V. parahaemolyticus 
in all the samples might be attributed to the favourable 
environmental temperature (26 to 27 °C) of the study 
site. 
A high pH value favours the growth of vibrios. 
As an example, the high pH value of the Coreaú river 
in Brazil was the most important environmental factor 
resulting in the great abundance of Vibrios in that area 
(Costa et al., 2010). Adding to this, Donovan and Netten 
(1996) considered pH 8.4-8.6 as an optimum pH value 
for the growth of V. parahaemolyticus. In this study, the 
pH value observed during sampling (pH 6.5-8.0) was not 
within the ideal range, yet the MPN value was more than 
1,100 MPN/g. Therefore, it could be deduced that the 
distribution of V. parahaemolyticus in this aquaculture 
farm was not affected by the pH value.
The samples examined in this study were collected 
during the rainy season, which might indirectly affect 
the salinity of the ponds. In this study, salinity ranged 
from 13 to 22 ppt and it  negatively correlated with the 
occurrence of V. parahaemolyticus. Our finding is not 
in agreement with Renata et al. (2010) who reported 
that there was no significant difference between the 
salinity and occurrence of V. parahaemolyticus. Besides, 
Prasanthan et al. (2011) stated that the salinity did not 
affect the growth of V. parahaemolyticus as this bacte-
rium is halophilic in nature.
Lastly, the risk assessment of V. parahaemolyticus 
in water and shrimp samples from aquaculture farms is 
of significant importance. According to the assessment of 
microbiological quality set by International Committee 
of Microbiological Specification for Foods (ICMSF, 
1986), the concentration of V. parahaemolyticus in Pond 
A and Pond B (5.9 x 108 CFU/ml and 1.3 x 109 CFU/ml, 
respectively) fall into the unacceptable class (Table 2), 
hence this poses the infection risk to human.
As a conclusion, this study demonstrated the dis-
tribution of V. parahaemolyticus in water and shrimp 
samples in a selected aquaculture farm. Since the pres-
ence of V. parahaemolyticus was detected in this study, 
a surveillance program for V. parahaemolyticus in aqua-
culture farms is therefore very important to prevent any 
foodborne outbreak due to the emerging pathogen.
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Risk of Acquiring Vibrio parahaemolyticus in Water and Shrimp from an Aquaculture Farm

Shabdin Mohd.Long

Sarawak Coastal Biodiversity: A Current Status

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Reality of and Problems with the Skill Development of Office Personnel of Public Elementary School

Kōchi University

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