SILKSTREAM™ COD-END DAMAGE FREE FISH TRANSFER SYSTEM

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Environmental Technologies, Inc. (ETI) is the world's leading supplier of damage-free fish transfer systems with over 1000 systems delivered worldwide. ETI's TRANSVAC® vacuum pump was introduced in 1982. The TRANSVAC® is designed primarily for transferring wild fish from fishing vessels to shore-based processing plants without damage. The TRANSVAC® and other vacuum pumps have also been used to transfer live fish with mixed results. Repetitive pumping of damage sensitive species, with a vacuum pump, often causes high rates of stress and occasional mortality.

The SILKSTREAM™ was designed specifically for transfer of live fish. Introduced in 1988, it took two years to design. Today there are more than 100 SILKSTREAM™ systems being used around the world, including more than 50 units used to transfer live salmon.

 

SILKSTREAM™ADVANTAGES

 HIGHER QUALITY PRODUCT - ETI has recently installed a SILKSTREAM™ Codend pump on the fishing vessel Aleutian Challenger. The Damage free "impeller- less" pump is manufactured by ETI (Environmental Technologies, Inc.) in Pacific, Washington. Originally designed for stress free transfer of live Salmon in the aquaculture industry, the SILKSTREAM™ Codend was redesigned to transfer fish from the codend of trawl nets and seine nets. The high capacity and ease of deployment make this pump a front-runner for trawlers and seiners, particularly if they are fishing for delicate fish such as Hake, Whiting or Hoki.

HIGH CAPACITY FLOW - The SILKSTREAM™ Codend transfers fish continuously at a high rate. The system can easily and safely transfer hake at the rate of 100 tons per hour. Herring, can be transferred at the rate of 200 tons per hour. The flow is continuous in the system, maintaining a high flow rate in the fish suction hose. For this reason, the fish do not have to be crowded to the extent required when using a standard vacuum pump. The suction flow in a vacuum pump stops movement when it shifts from suction to discharge, (or shifts from one tank to the other, in a twin tank system). This suspended flow in the fish suction hose, allows fish to swim back out of the hose. Therefore, fish must be crowded more drastically to maintain a good flow, with a vacuum pump. Excessive crowding normally causes stress in the fish.

LABOR SAVINGS - Transferring fish with the SILKSTREAM™ Coded generally requires only two people. Manual methods of transferring live fish are both very labor intensive and time consuming.

 

SILKSTREAM APPLICATIONS

ETI has recently installed an impellerless SILKSTREAM™ Cod-end pump on the F/V Retriever and F/V Dyrsten of Cape May, New Jersey. Owners of both of these vessels are exceptionally pleased with the high capacity and quality of the Herring and Mackerel being pumped directly from the Cod-end. The SILKSTREAM™ Cod-End pump transfers mackerel at rates of 80 - 120 tons per hour and Herring at up to 200 tons per hour, damage free. The entire system can be mounted on deck, however, both of these vessels have the power skid mounted below deck, under the water line to save deck space and eliminate the need to prime the SILKSTREAM™ Codend before each use. To empty the net, it is a simple matter of detaching the hose from the rib-line and attaching it to the pump with a quick-connect fitting. The SILKSTREAM™ Cod-End pumping system allows the skipper to continue idling toward port or the next set while emptying the net. Bill Loper, co-owner of the F/V Retriever says " The biggest advantage, of course, is the high quality of fish. The ability to continue searching for fish instead of being at the mercy of the wind and sea while filling our holds allows us to be headed to port ahead of the rest of the fleet." The indirect benefits of a SILKSTREAM™ Cod-End pump are also numerous. Longer life span for nets, safer working conditions for a smaller crew and no bulky pump to haul overboard into the net. Mike Buston, plant manager of Ucuelet Seafood Processors on Vancouver Island, buys Hake from two vessels with SILKSTREAM™ Cod-End pumps and says "There is absolutely no comparison in the quality of fish being split compared with that of fish being pumped. The SILKSTREAM™ Codend wins, hands down.". The SILKSTREAM™ Cod-End pump has been used to pump the cod-end of trawl nets for the past seven years. Recently, it has become more popular due to the need for fisherman to increase the quality and value from a limited quota of fish.

 

PRINCIPLE of OPERATION

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SILKSTREAM™ Codend system consists of a hydraulic driven water pump, the flow head and a dewatering/decelerator unit (elbow). Water is drawn, by the primary water pump and propelled through the flow head. Inside the flow head, the primary water is forced through a gap, around the full (360°) interior circumference of the head, and over a coanda surface which creates a continuous jet suction effect. The fish suction hose is attached to the suction side of the flow head. Suction created in the flow head draws fish and water into the system in a smooth and continuous fashion. After passing through the flow head, fish and water are directed through an "elbow" (primary dewatering system), where much of the primary water is expelled. The fish and a regulated quantity of water continues on from the "bazooka" to the system end point (i.e. a grader, sorter or dewatering box). The fish and water are dispersed and slowed at the discharge point.   The remaining water is also removed by the end point handling equipment. It is important to note that fish move through the entire system without passing through pump impellers or any other moving mechanical parts.