Commercial fishermen catch and process tons of fish a day. Many fishermen have complex, highly-automated processing equipment which dress the fish and produce numerous different commercial products for commercial retailers, such as restaurant chains or grocery stores. Such equipment is highly specialized to perform a specific task, such as cutting the heads and tails off, filleting, deboning, and skiing, etc. One of the reasons such equipment must be tailored to specific tasks is the large variety of shapes and sizes of fish processed, including pollock, salmon, trout, sole, cod, etc.
To reduce overall processing costs and to improve quality, commercial fishing vessels include processing equipment and freezers located directly on the ships. As the fish are caught, they are immediately processed and frozen, substantially improving the quality of the final product. This processing equipment also allows the vessels to remain at sea for long periods of time without transporting the fish to a shore-based processing facility. Most of the processing equipment is large, complex, and expensive. It is difficult and expensive to remove the processing equipment from the vessel and replace it with new processing equipment.
Because of the expense associated with exchanging the processing equipment, including vessel downtime, most commercial processing ships are intended to catch and process specific types of fish. As an example, a vessel may be fitted with processing equipment designed to process generally oval fish having a relatively thick cross-section, such as pollock or salmon, or generally flat fish having a relatively thin cross-section, such as sole.
Due to the natural migration of fish, and various fishing laws, individual types of fish are caught and processed during limited parts of the year. Therefore, vessels having equipment capable of processing only one type of fish sit idle during part of the year. If the processing equipment could be readily exchanged or adapted to process both oval fish, such as pollock or salmon, and flat fish, such as sole, the vessels could be operated over a larger part of the year. This would in turn reduce the amount of downtime and associated expense for the vessels.
One manufacturer of fish processing equipment is Baader GmbH & Co. KG, Lubeck, Germany ("Baader"). One of the fish processing machines produced by Baader is the Baader 182. The Baader 182 is designed to process pollock and salmon shaped fish and includes a conveyor having a plurality of fish holders mounted along the length of the conveyor. Each fish holder includes a recess configured to receive a pollock. While operating, a worker removes fish from a fish hopper located next to the conveyor and places an individual pollock in the recess of each fish holder. The conveyor subsequently moves the fish holders and pollock along the length of the conveyor into contact with rotating blades that cut both the head and tail of the pollock off. The body of the pollock is then carried to additional equipment that cuts the pollock into fillets and removes the bones and skin.
The Baader 182 works well with fish having an oval cross-section, such as pollock, but does not allow other types of fish to be processed. The Baader 182 is particularly unsuitable for processing fish with a relative flat cross-section, such as sole. The fish holders used on the Baader 182 are not capable of holding such fish during processing.
In order to adapt the Baader 182 to process fish having a relatively thin cross-section, the inventor previously applied for and received a patent on a device for holding flat fish during processing. U.S. Pat. No. 5,358,441 entitled "Device for Holding Flat Fish During Processing" issued to the present inventor on Oct. 25, 1994. The device for holding flat fish during processing allows the Baader 182 to process flat fish in addition to pollock. One embodiment of the device included a generally rectangular fish holder that replaced the fish holders on the Baader 182. The fish holders include two arms which extend over a portion of the fins and body of a flat fish and hold it in place on the fish holder. The arms include two recesses that have slanted rear walls that center the flat fish as it is placed within the fish holder. Two slots extend across the width of the fish holder to allow rotating blades to extend beneath the upper surface of the fish holder to ensure that the blades cut cleanly through the thickness of the fish.
One of the products that the device for holding flat fish during processing allowed the Baader 182 to be used for is the processing of "kirimi." In order to make kirimi, the head and tall of a sole are removed, leaving the center portion of the sole. The center portion of the sole is then sold to consumers who fry, bake, or otherwise prepare the center portion for consumption. In the past, the center portion was sold complete with any internal organs remaining within the center portion. One of the internal organs remaining in the center portion after removing the head and tall is the kidney, commonly referred to as the "blood spot." The blood spot is located along the backbone of the sole in the internal organ cavity. In the past, the blood spot has been either removed by the individual consumer during preparation or removed by hand during processing after the head and tail are removed.
In today's highly competitive fishing industry, it is generally not economical to remove the blood spot by hand, thus the blood spot is generally left in the commercial kirimi product. If the blood spot could be removed during processing, a higher quality kirimi product would result.
As can be seen from the above discussion, there exists a need for a method to remove the blood spot and any other internal organs remaining in the kirimi after processing. The present invention is directed toward fulfilling this need.