11.11.2014, 20:39:10 (GMT+1)
3D scanning technology to improve catch quality
Automatic fish sampling calculations will provide greater quality assurance
One of the important challenges facing Scandinavian fishing fleets is to increase the proportion of each catch that can be processed for human consumption.
The Norwegian pelagic fishing fleet, in particular, has been very keen to develop new and better systems for catch-handling and on-board storage to improve the quality of fish delivered for food production.
Pelagic purse seine catches are traditionally loaded by vane pumps and unloaded by vacuum pumps but these processes, together with the impact of contact with valves, can cause bruising, bloodspots and cuts on fish. Damaged products downgrades overall quality – which can obviously reduce the appeal of the fish concerned and the price paid for them.
Through economic necessity and to improve operational efficiency, the industry has been exploring and testing various alternative technologies to eliminate the causes of damage to fish during loading, storage and unloading. There are also other important reasons why innovations are needed to improve the catch quality and to raise the level of quality assurance.
For some years there has been a growing demand and an increasing value placed on higher quality pelagic fish such as herring and mackerel. Typically, buyers now insist on more precise weight class distribution and fewer damaged fish. These demands have added greater incentive and urgency to the need to find more accurate methods for weight and quality grading. When herring, mackerel and other species come to market, auctions are hectic and transactions need to be completed quickly. Quality assurance plays a big part in buyers having the confidence to complete transactions.
Catch quality and weight distribution are currently determined using manual computations carried out on board. This is time-consuming and, with pressure to come up with figures quickly, calculations need to be as accurate as possible. Often that is not the case and the figures quoted are described as something of a “lottery”.
For these reasons SINTEF, the largest independent research organisation in Scandinavia, has developed a ‘proof-of-concept’ system for making automatic catch weight estimates. As part of a development project funded by the Norwegian Fishery and Aquaculture Research Fund, SINTEF Fisheries and Aquaculture has created an automatic calculation system which can be installed on fishing vessels.
“The purchaser wants the fish to be the right size so that he can avoid tasks such as resetting his production line machinery,” says SINTEF researcher Aleksander Eilertsen. “They have to know what they’re buying – and quickly. A mistake can lead to heated discussions about the purchase price when the catch is landed for weighing checks.”
This is how the concept works. The new system automatically takes random samples of fish for weighing and then returns them to the catch tank. Robots with 3D vision calculate the spread of fish seizes and weight distribution, identify the fish type and record any damage to the catch. The automatic fish sampling and single fish weighing provides a meaningful estimate and clarifies catches with high levels of accuracy which saves fishing crews time and money.
Other quality control features in the new system include:
• loading by negative pressure – avoiding pump blades that can harm fish
• new water separation equipment with a large drainage area to separate fish from seawater safely and effectively
• cylindrical refrigerated seawater (RSW) tanks for rapid and stable chilling
• automatic cleaning of RSW tanks to improve hygiene
• unloading the catch by pressure instead of vacuum systems with flap-valves – which avoids pipe bends and valves that may cause damage.
“In the past it has been essential to separate all the fish in order to handle them individually. However, on-board 3D scanning makes this no longer necessary,” says Eilertsen. “We believe this system will be very useful because pelagic fish are caught using purse seines. These nets can be as much as one kilometre (1,093 yards) in circumference and a single cast can result in a catch of up to 1,000 tonnes. This is an enormous volume of fish and means that the margins of error in any weight estimates can be very significant.”
The new system was installed and the concept tested fully on the Norwegian purse seine vessel M/S Christina E. SINTEF says the system is now ready for commercial operations.