 TRƯỜNG ĐẠI HỌC VINH    !  "#$%&'()*+*,+-./0+1,12 &34!54(6 #(&$7%8 ('(9 :("%  ;<=-,>?@>-ABC DEB;FBG- ;<=-><HB;IJBK>D1>L@C7%M%;N0OB>PQNRB>N S34TT  #U Để hoàn thành bản luận văn này, tôi đã nhận được rất nhiều sự giúp đỡ của các tập thể, cá nhân. Từ đáy lòng mình, tôi xin trân trọng cảm ơn những giúp đỡ quý báu đó: Lời đầu tiên, tôi xin trân trọng cảm ơn tới Ban Lãnh đạo Phân Viện Nghiên cứu Nuôi trồng Thuỷ sản Bắc Trung Bộ, Lãnh đạo khoa Nông Lâm Ngư, Khoa sau Đại học của Trường Đại học Vinh đã tạo điều kiện cho tôi hoàn thành khoá học này. Tôi xin trân trọng cảm ơn tới PGS.TS. Nguyễn Thị Xuân Thu, người hướng dẫn khoa học, đã định hướng trong nghiên cứu, từ việc lập đề cương đến triển khai các thí nghiệm và hoàn thiện bản luận văn này. Cuối cùng, tôi xin gửi lời cảm ơn chân thành tới người thân, bạn bè, đồng nghiệp đã động viên và giúp đỡ tôi trong quá trình triển khai thí nghiệm nghiên cứu và hoàn thành bản luận văn này. Vinh, ngày 20 tháng 12 năm 2011 V@;-W   #  7X #U # YZ$([!\  X ]^ ><_B;TM9 ` a(           !"#$%&"'( )*"#+!,- .    //01 2 3 4)*"56, !7/8%&3 -)*"56,"9%:;3 <= > = > 0 ?  > 2      @ <= > = > 0 ?  ? 1 ? @ <= > = > 0 ? 1  A  B3 ><_B;3M777'(C !0DEC <F%G6EC .H01"5"EC .H01" ? "+!II C .H01"5"/JI . ..H01"5"KL!  ><_B;bMY!a('(#(.4  .M0N,O570N%P !, $!Q7RQ%S01.4 .T57!90FI .4 .M0N,O570N, $!Q7RQ%S.- ..M0N,O57P !, $!Q7RQ%S.C .M0N,UV70N %P !, $!Q7RQ%S4Q .T57!90FI 4Q .M0N,UV70N,4 .M0N,UV017P !,4. ..W  01    0 ?  ? 01   > P  9 ?    $!Q7RQ%S0144 ..T57!90FI 44 .M0N,E70N,4- .M0N,E7X !,4@ Y!#(Q(^4R  c #' d (Y ` 4C  YZ$(!\ WBYAW Z H#I"01 T< Z T9E T<A Z TV5 [Y Z \% W] Z ^5G_: `B Z ^5Ga: )^b Z )"cd  e( e&.T57!90FI .4 e&.Z<0N,O/%N5O5f5 .- e&..Z<!V0N01!OO/%,.@ e&.4Z<P !,N59EI .C e&.-T57!90FI 4Q e&.3Z<0N,O/%N5UV01 f54 e&.@Z<P !,N59EI 4. e&.RT57!90FI 4- e&.CZ<0N,O/%43  X gBe7<h)d+R- gi6:$,a. g.T:$,. g4A;9N<5- g-T5$"56,@ = > )19 > +9 ? = ? = ?   C gZM5+!II . g.j:'%fI0_. g.Ze6k0N,OO/%N59EI .3 g.e6k!V0N01!OO/%,01 N59EI .R g..Ze6kP !,N5EO5f5.C g.4Ze6k0N,OO/%N59EI 4 g.-e6kP !,01N5UVf544 g.3e6kP !,01N59EI 4@  ]^ Be7<Meretrix lyrata) > 9 ? 01   ?  ?   f ? / l  01 > # ? f#  %8VGf51 ? m 2 #  91   h" > 1  "1 ? = > 9   ?   01 > /#01   > 9 ? 01   99 >       *,OG"01+6 ? h/  = ?  9n  01 ?  > @@h  01  01 ?   R3Q.# ?  T  99 >     hQQR<01 ?  ? " ?    >  ? "0   > # >  9 ?  >  > = >   f ? 9 ?  2 /21  # >  ?  ?   "01lO9"56h%7!f9+O o!1 ?  > 9 p  A  B  #   2 * 0 > QQ.0 qg&:!0r h0lE%O $01!<*7h"# > 01 > /#  *7"  ? 9+ 2  > P   # ? 1 ? /i"    h9 01 > +# ? 1  hsA 01!6#P ! 0D%0__hlIf&N5;l5t9 9+G+aX9u8FX.u@5 ]# ? " ? 0 > # > 0   ? h0 ? v                !  "#  #$%&&' !(  )*+,-+#./0Di6% qg& :!w#P !q5g01! 8,UZ^l""t% qg&:! BV/EZ  BE&0N,O570N%P ! ,$!Q7RQ%S01  BE&0N,UV70N%P !, $!Q7RQ%S01 . BE&01    0 ?  ? 01   > P  9 ?    $!Q7RQ%S01  ><_B;TM 9 ` a( TMTMF d @f-g ` hi-B>>D d @@N ` 1B;>gN)%&&'!( 0101012)3!4 536#7 Be7< Meretrix lyrata )d+hR-hl7% jWh"#+!"I<#<5eg[01hx%j7A  BAa/%yhlg/$!5_aOh +&OwNi0haNNi+8^F0N"I0_a9 %#hN"IaG1m_"+&Ol.o%+ A71fz"a0_ahg+5 h71fz"a"I_1h gi %y,a"I%%$h%yoi %#hial#hil%y A,>jB;k>RB/Dl- <+ > C33%B{TICC3h !"#$, 0Z B%Z j_"Z&ae eVZ/ (ZA/ ^!Z j%Z)d+hR- mB>TMTM;>gNnB+*)%&&'!%Do*+p0T5qT2  . tới ngư i thân, bạn bè, đồng nghiệp đã động viên và giúp đỡ tôi trong quá trình triển khai thí nghiệm nghiên cứu và hoàn thành bản luận văn này. Vinh, ngày. Xuân Thu, ngư i hướng dẫn khoa học, đã định hướng trong nghiên cứu, từ việc lập đề cương đến triển khai các thí nghiệm và hoàn thiện bản luận văn này. Cuối