9420.pdf

4 PROCESSING TECHNOLOGY
The five major types of fish processing
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Groundfish processing;
Salmon processing;
Herring processing;
Shellfish processing;
Surimi processing.
on Canada’s West Coast are:
Each group has a unique production process. Variation in processing procedures are
found from plant to plant, but the major features of each type of production are quite
consistent and are discussed below.
4.1 Vessel Unloading
Vessel unloading is common to all fish processing. It can be done with wet (siphon) or
dry (vacuum) pumps, or with buckets or baskets. Dry pumps result in rough handling of ,
the fish and are generally only used for ground fish due to the relatively low commercial
value of the fish. Wet pumps are much gentler and are used for freshly caught herring
and salmon which are kept in water inside the holds of fishing boats and fish packer
vessels during transport. The pumps use large diameter hoses to pump water and whole
fish out of the vessels’ holds. Water and fish are then discharged onto grating to allow
the separation of fish and water. A certain amount of water is recirculated to the vessels
to ensure sufficient water for the operation of the pumps and to be able to remove all fish.
The water level in the vessel is continually lowered during the unloading operation and the
vessel, generally, is almost completely empty when all fish have been unloaded.
Conveyors pick up the fish after their separation from the vessel hold water and transport
them to grading stations, where the fish are manually sorted according to their species.
After sorting, fish are kept in chilled water or ice for intermediat’e storage until they can
be further processed. Grading is not required for herring.
Baskets or buckets can also be used to unload vessels but are, generally, only used if
small quantities of fish need to be unloaded, or to offload frozen fish. In these cases
baskets are lowered into the vessels holds by a crane and filled with frozen fish. -
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