| dc.description.abstract | Shrimp trawling has aiways been associated with large bycatches. The problems are
solely due to the small mesh sizes generally used in shrimp trawl compared to mesh
size in trawls used for various groundfish. During the last 25 years, a lot of
experiments have been performed to reduce the bycatch in shrimp trawl, but so far
one has only partly managed to solve the problem. It still remains to develop
devices that effectively separate small fish from shrimp and small shrimp from
larger shrimp, that is a combined solution for species and size selection in shrimp
trawl.
I The survival of one-year-old cod (Gadus morhua), haddock (Melanogrammus
I aeglefinus) and whiting (Mer1rn1~ti.sm eriangius), excluded fiom a shrirnp trawl by
a diagonal metal grid placed in front of the codend (the Northmrre grid), was
studied during June 1993 and 1994. Fish leaving the gear in fiont of this grid
during trawling were retained by a net covering the fish outlet, and led into a I - collecting cage. The colleding cages were released from the trawl at the fishing
daily by underwater television, and in the second season aiso by divers. The
escapees from separate trawl hauk were anaiysed for body darnage.
No mortality was found among the young gadoids during the observation period,
except for one haddock in the control group. There were almost no visible skin
injuries or scale loss in cod, while in whiting and haddock there was a significantly
larger occurence of these factors. No correlation was observed between fish size
and the amount of scale loss. | en |
