envelope-type construction of the …fishbayproject.pl/files/envelope.pdfbacoma codend a. extension...
TRANSCRIPT
ENVELOPE-TYPE CONSTRUCTION OF THE CODENDS USED IN FISHERIES
• PROPOSAL OF NEW CONSTRUCTION
FOR T90 AND BACOMA CODENDS
Krzysztof Stanuch , Andrzej Boczkowski
Seminarium Dziwnów 12.08.2015
BACOMA CODEND
A. extension piece
B. codend
C. Escape window , square mesh panel
1 upper panel max 50 open diamond meshes
2 lower panel max 50 open diamond meshes
3 selvages
4 joining round or lacing
5 lifting strap
6 back strap
7 codline
8 distance of window from codline
9 buoy rope
10 codend buoy
production of BACOMA codend
codline gathers all meshes
to one point of codend
T90 codend
T90 codend
MESH OPENING IN REAR PART OF CODEND
shape of mesh in VI row
shape of mesh in I row
MESH OPENING IN REAR PART OF CODEND
shape of mesh in VI row
shape of mesh in I row
… according to ICES conclusions , both BACOMA windows and T90 codend give L50 of 38-40cm, which is equivalent to the MLS for cod of 38 cm. For T90, the preliminary analysis of the German and Polish data give L50s of 41 cm and selection ranges of 4,8 to 6,5 cm. Overall no difference in selectivity between the two gears could be detected , but nethertheless, it could not be excluded.
REPORT FROM THE COMISSION TO THE COUNCIL on the selectivity in trawl fisheries for cod in the Baltic Sea COM(2008) 870
• what more we can do to minimize the problem of discards ?
•The gear selectivity reached and even exceeded the MLS of 38 cm
NEW PROPOSAL OF ENVELOPE-TYPE CONSTRUCTION OF THE CODENDS SHOULD DECREASE SELECTION RANGES AND BY THE SAME SHOULD DECREASE DISCARDS OF UNWANTED FISH !
NEW ENVELOPE CODEND upper/lower panel
proper cut in wedges in the rear part of codend gives
the square meshes in this part, fully opened all the time
during towing
These meshes are turned by 45° in relation to the
selvages, thus have the same pattern as in BACOMA
window.
NEW ENVELOPE CODEND upper/lower panel
proper cut in wedges in the rear part of codend gives
the square meshes in this part, fully opened all the time
during towing
These meshes are turned by 45° in relation to the
selvages, thus have the same pattern as in BACOMA
window.
„ENVELOPE-TYPE” ENDING OF THE CODEND
according to new construction
selvage
Advantages of a new design
• better selectivity without mesh size increase • higher escape level of undersized fish • discards reduction • reduction of the gear selectivity range • better water flow in the trawl and codend • universalism • simplicity of the design • low cost of the required changes • for implementation in almost every type of codends
what next?
•Consultation with fisherman in order to adapt the design to the constructions currently in use; •Research with the use of fishing vessels; • presentation of the research results; • implementation.
Thank you