ARCHIVED – Aquaculture Innovation and Market Access Program - Project Summary

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As part of improving productivity by mechanization, several projects have been completed.

First project: Optimizing equipment for harvesting mussels at sea.
Loss of mussels by dropping out can represent a significant financial loss for a marine farmer. Research into available technologies identified a new type of harvester in the Netherlands which is based on the venturi principle. This harvesting system draws in water at the same time as the mussel sock, detaches them from the sock, and drives them onto the deck with the water. The main objective of the project was to test the effects of the harvesting method on loss from dropping out. The high heterogeneity observed on the socks made analysis difficult, but underwater observations confirmed that the venturi harvesting method results in lower loss than the conveyor harvesting method. The second objective was to compare the effectiveness of mussel sorting by the conventional drum declumper and by the conveyor sorter of the venturi system. The harvesting method associated with the drum declumper provides better sorting efficiency than the conveyor sorter of the venturi system. The percentage of commercial size mussels collected at the end of the sorter was 83% for the drum declumper and 75% for the conveyor sorter of the venturi system. The third objective was to compare the harvesting methods in terms of labour time. Extrapolating measurements taken during the tests, collection of a complete 6240 feet longline would represent 4 hours of work with the venturi system and its sorter while it would require 9½ hours for the same work with the conveyor coupled to the drum declumper. Consequently, the venturi system is 3.4 times more efficient.

Second project: Optimization of harvest and separation of softshell clams using mechanical equipment.
The objective of this study is to increase yield from harvesting and sorting operations (i.e., reducing labour required) through design of a new harvester-sorter using the hydraulic rake principle. The essential elements for design of a prototype are that it must be manageable while minimizing breakage of the clam's shell. The prototype must be able to sort clams of commercial size, smaller ones, or to collect spat. After many discussions, we have come up with a venturi type device. Following tests with this device, the viability and effectiveness of this type of system have been demonstrated. The advantage of using a venturi is that it does not require any additional mechanics since jets are used to remove silt from the clams. The parts and tools that the harvester uses to operate were carefully studied to conserve mechanical simplicity while making it easy to use. Fabrication and testing were done with the basic concept, with the jets and venturi mounted on a frame on wheels for moving. With the concept having been proven, further work was begun in the summer of 2009. Installing the sorter on the harvester results in time savings, since only 5% of the residue (i.e., rejected material consisting of shells and small clams) has to be removed after the harvest.

Third project: Developing a decoiler to improve performance of the mechanized socking operation.
A prototype decoiler intended to facilitate deployment of rope coils was developed. This prototype was designed to facilitate socking of mussel spat. It often happens during this operation that work has to be interrupted because the rope becomes tangled. The decoiler prototype consists of two sub-assemblies, each having a specific function. First there is the tank itself. The decoiler operates so that the rope is always kept in suspension in the water to keep tension as uniform as possible and to get a better sock. The second sub-assembly of the system is the gooseneck. This device also functions to help keep a uniform tension on the rope. Even though the tank system greatly helps the rope to unroll smoothly, there may still be the occasional tangle. The gooseneck provides some safety from this effect. With an affordable fabrication cost, estimated to be about $2,700, and a weight of about 140 pounds, this device can increase efficiency of socking at an aquaculture site.

Fourth project: Developing a mechanized washer for floating buoys used in mariculture longlines.
Like the sock and other parts of a submerged floating longline, the buoys that support them capture spat of mussel and other epibiont species. To avoid compromising buoyancy and risking the droppers touching the bottom, cleaning the buoys is done several times during the mussel growth cycle. After several failures with the original principles, the idea took shape of a tunnel into which the buoy is inserted and cleaned by steel cables under tension. This lets buoys of 12 to 16 inches diameter be cleaned without resorting to any complex mechanism. Approximately 75 to 80% of dirt, regardless of the type, was removed after passing through the washer. For best results, the buoy can be passed through the washer a second time by orienting it which will then remove about 90 to 95% of the dirt. From our observations, cleaning with the cleaning machine does not slow down operations on deck. After recording several times, the average cleaning time while harvesting was 7.5 seconds - however it should be mentioned that this time can vary from 3 to 17 seconds depending on the line speed. We calculated that cleaning with the buoy washer is about 4 times faster than the conventional method and requires less effort by the worker. It should be noted that it is not necessary to have a person dedicated only to cleaning since the same person can be doing something else which therefore facilitates each person's tasks. The buoy washer cleans acceptably and avoids a great deal of repetitive movements (source of injuries) without losing time and at a very acceptable cost.

Proponent: Société de développement de l’Industrie maricole Inc. (SODIM)

Total project cost: $348,750
DFO-AIMAP Contribution: $86,000

Other Financial Support:

For more information about this project, please contact the regional coordinator.

Quebec Region: