EXPERIMENTAL STUDY ON TECHNOLOGICAL INNOVATION ON STOW NET FOR CATCHING STIMPSON

Based o n the behavio r o f st impson( Tr achypenaeus) and the f ishing methods of st impso n stow net , two new kinds o f stimpson stow net, the hand-knit ted and the cut net s, w ere designed w ith the characterist ics of big sha pe, pr oper st ructur e and impro ved wo rkmanship. The result s of the model test in a tow ing ta nk indicated tha t the dr ag against the cur rent per unit area o f the mo uth o f the ha nd- knit ted net and the cut net is 70%~ 76% and 64%~ 66% of that of the co nvent ional net respect ively . The result s of the compar at ive test s betw ee n the new net s and the o ld one on bo ard dur ing the spring f ishing seaso n in 1993 and 1994 showe d the y ield wa s incr eased by 30. 1% ~ 61. 6% f or the hand-knit ted net and 43. 3% fo r the cut ones. The results of 29 gro ups o f 10 t imes random sampling o f ca tches dur ing tw o years ' ex per iment at sea showed tha t the number o f juv enile stimpson ca ught by the t ria l net s w as reduced by 23. 7% and less f ish w as ca ught , especially the commercial species as compared w ith the co nvent ional net . A special test s on bo ard also show ed tha t the juvenile f ish and shrimp relea sed f rom codend and kept for 18, 30 and 54 hour s wer e mo stly alive. This result pro vided scient if ic informat io n for the techno lo gical inno vat io n on stow net and could be used as refer ence to the impro veme nt on o ther f ilter net s.