Evaluation and Further Development of the iCage™ Fish Containment System as a Technology Platform to Meet Sustainability and Cost Reduction Targets

Admiral Fish Farms Ltd
AIMAP-2009-M14

Table of contents

• 1) Executive Summary
• 2) Introduction
• 3) Project Overview
• Project Objectives
• Construction
• Stock Transfer
• Orientation and Activities
• 4) Results
• Integration of Feeding
• Mortality Removal Without a Diver
• iCage™ Assembly and Engineering Improvements
• Buoyancy Control
• Fully Enclosed Bath Treatments
• Handling Methods
• Ancillary Assessments
• 5) Conclusions
• 6) Communications

1) Executive Summary

Admiral Fish Farms identified an innovative fish containment system being developed in by Open Ocean Systems that eliminates the use of copper based antifoulants. The units were placed at the Hardwood Island farm site in Passamaquoddy Bay, New Brunswick. This was the first ever construction of a 4500 m³ iCage™. Open Ocean Systems designed the 4500 m³ to increase the size of previously constructed cages of 2250 m³ during prototype development in New Brunswick and beta trials in Belize. The iCage is designed to interrupt the life cycle of biofouling organism using its rotation ability which exposes the netting surface to the sun and wind.

This AIMAP project had two objectives: 1) To assess the ability of the iCage ™ fish containment system to eliminate the use of copper based antifoulants while reducing overall all net maintenance costs and related activities within a commercial scale salmon farm; and 2) To continue the development of the iCage™ platform into a viable farming system alternative for the Canadian farmed salmon sector.

The first project objective was highly successful. The Dyneema™ net was placed on the iCage™ on November 15, 2009 and was removed on January 17, 2011. The net was not changed during this period. It took minimal rotation maintenance and two washings of the ring sides to keep most of the netting free from fouling. Approximately 15 % of the net surface, mostly the ring sides which are not regularly exposed to the sun and wind during rotation, had moderate fouling. The fouling consisted mostly of hydra, tunicates and mussels. The traditional cages at the site had three nets placed on them during the same period of time in order to maintain a sufficient enough water flow and dissolved oxygen within the cages. Ambient oxygen levels were maintained in the iCages™ throughout the entire project without the changing of nets or application of antifoulant.

The second objective resulted in the development of some significant milestones. Open Ocean Systems was able to assess the structural ability of the cage and make necessary improvements in engineering. Working in collaboration, we have improved accessibility for routine procedures such as feed camera installation and fish sampling. Trials for seining, stock transferring and sea lice bath treatments were all conducted with successful results.  

There is full confidence that the project results have shown this technology to be of great potential in benefitting us on our sustainability path, by eliminating the use of copper based antifoulants. Admiral Fish Farms has moved forward with an investment of two more 2700 m iCage™ units at a site located in Back Bay, New Brunswick. These units were constructed and had stock transferred into them in December, 2010.

This project has played a valuable role in continuing to enhance the company’s ability to grow as a producer of high quality, sustainably farmed seafood.

2) Introduction

Bio fouling occurs on any structure that is placed in the water. This biofouling directly impacts the netting that contains the fish being cultured. The biological growth impedes the flow of water into and out of the cage, reducing the amount of oxygen available to the fish in the cage and impairing the removal of metabolites from the cage. This creates a sharp reduction on the quality of the growth environment for the fish, leading to fish health and productivity issues. The current means of mitigating biofouling is by placing a new net around the fouled net and then removing the fouled net. The fouled net must then be taken to a treatment facility where it is washed, tested for strength, and antifoulant is applied. The current antifoulant applications used are copper based and may cause adverse health effects in the marine environment. This activity takes place an average of four times between introduction and harvest of salmon in the Passamaquoddy Bay area.

The iCage™ is designed to expose sections of the net intermittingly and disrupt the biological life attached to the netting and cage surface. The netting is made from Dyneema™ and is an extremely strong, light weight, non-absorbing material. These two features of the iCage™ combine to make the application of antifoulants unnecessary.

Hardwood Island Marine site 0052 had Atlantic salmon smolt entered in the 2009 year class as it lies within Bay Management Area 1. The site is located southeast of Hardwood Island in the upper part of Passamaquoddy Bay. The site was identified as a potential location for the development of the 4500 m³ iCage™ designed by Open Ocean Systems. This was the first ever construction of a 4500 m³ iCage™. Open Ocean Systems (OOSI) designed the 4500 m³ to increase the size of previously constructed cages of 2250 m³ during prototype development in New Brunswick and beta trials in Belize. This volume increase would provide more growing area per unit leading to more cost effective growing volumes at applicable locations for the salmon aquaculture industry.

3) Project Overview

Project Objectives

There were two key objectives set for this AIMAP project:

1. To assess the ability of the iCage ™ fish containment system to eliminate the use of copper based antifoulants while reducing overall all net maintenance costs and related activities within a commercial scale salmon farm.
   
   
2. To continue the development of the iCage ™ platform into a viable farming system alternative for the Canadian farmed salmon sector.

Construction

The Admiral Fish Farms team began placing moorings for the iCage™ system on September 14, 2009 and finished the mooring placement for the first of the two cages the following day. The concrete blocks were placed with guide ropes to help orient the blocks properly. The blocks were then towed slightly to assure proper placement. The Northeast corner of the lease was chosen for the placement of the first cage where the water is roughly 30 meters in depth.

The Southeast corner of the lease was chosen for the location of the second cage. The guide rope strategy was also used for placement of the second mooring system. The water was deeper which lead to difficulty moving the blocks after initial placement. Proper orientation and placement of the blocks proved to be more challenging and time consuming because of these conditions. The mooring system was successfully completed on November 12, 2009.

Construction begins, similar to traditional cages, by fusing float pipes together, loading the pipe with connectors, locking them in place, and forming a ring. The major difference is the addition of spokes. Completed rings are floated to a temporary mooring where hubs are installed. This underwater hub installation technique had never been proven, until the Hardwood build. This technique proved to be quite effective, and became the installation procedure going forward. Once hub installation is complete, the ring assembly is ready for standing and axle attachment. The axle is pulled into place and submerged to the hub level. The axle is designed to slide onto the hub insert, once properly aligned. The opposite end of the axle gets inserted onto its hub insert, in a similar fashion, and the ring timing is set. This sliding onto the hub action had not been proven until Hardwood. Previous axle/hub unions were performed by threading the axle onto the hub, which was very undesirable, and flanging the axle to the hub, which was very difficult to align. Sliding the axle onto the custom machined hub insert proved to be effective and became the installation procedure going forward.  At this point, the cage is ready for arch installation. Arches are installed below the surface, to take advantage of the near neutral buoyancy, and to reduce the effects of wave action. Current speed and direction is the main factor to overcome. Two arches per day using four divers was the output of the install team. Completion of the arches ends the cage structure phase of the process. Net Installation and tensioning takes place next. The light weight untreated Dyneema™ netting easily handles in a small boat with limited manpower. The net is placed on the cage structure loosely, by connecting the net at the arch corners, and then rotating to the next arch, until the starting arch comes back around. At this point the two ends of the net will be sewn together. Ring tension ropes are attached and tensioned to maintain the proper distance between flotation rings, and to help tension the net and retain volume. Net ties are placed in around the spokes, arches, and rings. It is leveled on its mooring system, and ready for fish.

As expected, Cage 1 took longer to assemble than Cage 2. Several methods used in Cage 1 were altered. For example, it was determined that installing the spokes on the beach would be much easier than in the water. What took us four days on cage 1 was reduced to less than four hours for cage 2. Cage 1 arch installation involved determining the best cage orientation, to accomplish this task. Several methods and locations were tried to identify the optimum method. Alternative methods were identified for use on higher wave activity days, though less efficient, they make it possible to continue moving forward on marginal days. Open Ocean Systems were successful in identifying key areas for improvement with regards to efficiency.

Stock Transfer

Fish were transferred into the iCages™ on December 2 and December 28 of 2009 using a passive swimming method. The iCages™ were towed from their individual mooring locations, to the existing polar circle cage and back. This had never been done before. Previous methods for fish transfer involved bringing the circle to the iCage™. Moving the iCage™ was performed using two boats. One boat would adjust its power up or down to turn the cage, while the other boat maintained constant power. The transferring of the fish was successful with very low mortality levels and normal fish behavior.

Orientation and Activities

We began orienting site workers and divers to the cage and the operating procedures. The fish were fed by conventional means of gas powered air delivery feeders. The cage was rotated by tying to the cage and powering the boat forward.

At the end of December we observed the first benefits of the innovative cage structure. A freezing spray icing event occurred at the site. Substantial winds from the north and northwest persisted for a period that lead to significant icing on the adjacent polar circle cages and nets. This condition leads to manual removal of the ice to relieve stressful weight conditions on the cage. The task is labor intensive and time consuming. Although significant labor hours were spent removing the ice from the polar circle cages, no time was necessary for removing ice from the iCages™. The netting and cage surfaces did not collect ice in a manner that warranted removal. This continued to occur during the next few months and all icing events.

During the months of January, February and March several operational tasks were completed when weather permitted.

The adjustment to the mooring system continued to attain a cage orientation condition that was favorable for feeding and rotating. The adjustments were made by increasing or decreasing the amount of air in the floatation rings of the cage and the floatation buoy. The adjustments were a guess and check system that required tidal cycle time between them for proper assessment for results of the adjustment.

Inspection dives were completed of cage, net, moorings, lines and connections. The fouling was monitored on the net and cage surface and was found to be very slow during the winter water temperatures, which were warmer than historically. A light slimy fouling, greenish brown in color, was observed on areas of both cages during inspection dives on February 15. The fouling was almost entirely in the ring area of the cage that remained submersed during rotation, with the exception of a few panels on the arch sides that were in the water for periods during mooring system adjustment. These areas would be expected to clean off, now that the cage was sitting higher after adjustment. We continued monitoring from the surface and those areas cleaned off when held in the cold air for only a couple of hours at a time.

The cages were visually inspected by boat in some high wind conditions to assess how the cage behaved during period of choppy seas. The cage was found to have little movement due to the attachment area of the mooring system to the cage (7-8 m under the water surface) and tension of the mooring systems.

Another detailed inspection dive conducted on March 15 showed no significant increase of the fouling area, the amount of fouling, or diversity of organisms. The water temperature was warming quickly reaching 4° C before the end of March.

Time was spent orienting site crew and divers to the cage structure and operating procedures which led to the documentation of draft SOP’s.

On March 17 we conducted the first raising of the iCage™ in preparation of bath treatments. The raising of the cage would reduce the volume to the required amount for the treatments. We were able to raise half the cage out of water by releasing the air from the floatation buoy and adding compressed air from dive tanks to the floatation rings on the cage.

On April 8 and 12 the cages were raised again and bath treatments were successfully administered. The raising of the cage allowed for a good assessment from the surface of the overall fouling on the sides.

We raised the Northwest side of iCage™ 16 on April 21 and allowed time to dry in the sun and wind. Although this procedure does not remove the fouling, it does dry and kill it, which made it easier to wash.

It was decided to initiate the first high pressure cleaning of the ring sides of the cages. On April 29 and May 5 the cages were washed by divers. It took 4 hours on iCage™ 15 and 12 hours of diving on iCage™ 16.  The rotational aspect of the cage was used to keep the fouled ring area closer to the surface, increasing the amount of time that the diver could remain in the water by minimizing the water depth of the work. iCage™ 16 was more heavily fouled due to the fact that it had been installed 30 days sooner in warmer water temperatures. Minimal fouling occurred before the water temperature dropped and this fouling made a greater surface area for more fouling.

With the cages cleaned we continued developing SOP’s for rotation and feeding. Buoys were tied to the cage to eliminate it rotating on its own to ensure that a particular area of net would remain at the surface for drying. This proved to be a tedious task for crew and was discontinued as an operating procedure. The cages would be left to rotate freely and were purposely rotated by crew twice a week.

Over the spring and early summer, a number of factors combined to expose a material performance issue with the iCage™ 15 arch side components, which eventually manifested itself in a gradual deterioration of the arch side performance. The cages were inspected and analyzed in detail by Open Ocean Systems engineers and designers, with detailed plans to address the issue in both the short and long term.

We conducted the seining trials on June 21. The trials were successful in capturing and crowding a good percentage of the population within the cage. The negative aspect of the current seining procedures was the fact that it involved a lot of diving time to install the seine. This would be expensive and time consuming for the farm. We would need to continue to explore other, more cost effective and timely, solutions for removing fish from the cage.

In the beginning of July we started to see more benefits within the iCage™. We started to have oxygen depletion in the traditional cages which restricted production and operational procedures. The nets in the traditional cages were placed on the cages in close proximity of the installation of the iCage™ nets yet we were beginning to see significant fouling occurring on the traditional cages. Oxygen levels in the traditional cages were well below ambient levels but the iCage™ continued to have ambient levels of dissolved oxygen. The fish in the iCages™ continued to eat normally and feeding was not restricted due to low dissolved oxygen levels. It was necessary to discontinue feeding and bath treatments, because of the low dissolved oxygen levels within the traditional cages, and change the nets.

The arch performance issue noted in the project earlier eventually spread to other arches within iCage™ 15 and started to impact net management and other issues. Extensive audits of the arch conditions were conducted in July by Open Ocean System engineers. A collaborative decision was made to remove the fish from the cage before fouling became a fish health or security concern. The ring areas of the cage and net were cleaned and prepared for transfer July 27 and 28. The stock was passively swum into a 100 meter traditional cage on July 29. The net was removed from the cage during the transfer mostly by hand and with the aid of a crane to place on a barge. The cage was then towed back to its mooring system and the float buoy was filled with air to submerge the cage.

Focus was then placed on the remaining cage. The arch performance issue was much less dramatic in this cage and Open Ocean Systems were confident that arch development and replacement would help to lessen it further and get the fish to harvest in the cage. A program was developed to begin replacement of the arches that were most affected. The arch replacements were constructed during the month of August and were put into place in the beginning of September. The new arch pieces performed better although some deflection was still observed. The deflection of the new arch was minimal enough to provide the confidence that the functionality of the cage would not be lost. The tension of the net was also adjusted to alleviate further stress on the arches.

In August there was an epidemic infestation of sea lice at the site. Mortality elevated in the surface cages but remained low to moderate in the iCage™. The lice load appeared to be less when compared to the stock in the traditional cages.

On August 31 a fully enclosed tarp treatment was conducted on the iCage™. The tarp was badly damaged from contact with the flange bolts on the cage. This will have to be mitigated in future treatments. Also the rotational aspect of the cage was not utilized to place the tarp on the cage resulting in most of the damage. Further, a tarp designed to be used for 100 m circles was used. This caused excess corner pieces to float around loosely. Major damage occurred to the tarp when it was wound up in the propeller of one of the treatment boats.

A forecast of Hurricane Earl prompted a submersion of the iCage™. On September 3 Open Ocean Systems filled the float buoy to submerge the cage. The cage went under but would take one tidal cycle to work its way down further. The cage was inspected by divers after submersion. The cage was in good condition and fish were behaving normally. The cage was surfaced on September 7 after the storm had passed. Air was released from the float buoy and some air was also needed in the rings to complete the cage surfacing. The fish were observed breaking the surface similar to feeding activity for a period of approximately 15 minutes. It is assumed that they were filling the air bladder which aids them with their equilibrium and easier swimming ability. The fish returned to normal schooling activity and there was no elevated mortality within the cage. The submersion period was approximately 96 hours.

During September and October, site MF 0502 Hardwood Island continued to have an epidemic infestation of sea lice which lead to higher than usual demand of resources to repeatedly treat the site using a wellboat. Wellboat treatments require that all fish be removed from the cage and enter the boat for treatment after which they are discharged back to the cage. There were some uncertainties operationally around this treatment option for the iCage™. The first was securing such a large vessel to the cage and mooring system. The second was the time consuming process for seining the fish into the boat if it could be secured properly. The third was the weather that occurs at the site during those months which make it difficult to accomplish either of the first two. Without the wellboat as a viable treatment option we decided to continue to monitor the fish and initiate another fully enclosed tarp treatment if possible.

The treatment that occurred on the cage August 31 was successful in lowering the sea lice level for a few weeks. The mortality became extremely elevated in the end of September and continued through October. Subsequently all fish died due to heavy lice infestation levels. The last large mortality removal from the cage took place on January 5, 2011. A sweep of the net using a cork line was performed and the net was then removed on January 17.

4) Results

Integration of Feeding

Feeding was conducted from the surface using air delivery systems. This integration had challenges related to the tidal flow through the cage. The Dyneema™ netting does not disrupt the tidal current as significantly as traditional netting therefore the current remains stronger in the iCages™. The structure of the iCages™ allows fish to remain deeper in the water column than in traditional cages and it was continually observed that fish remained in the lower part of the iCage™.

With these observations and feedback from Admiral Fish Farms, Open Ocean Systems has begun development to integrate a water feed delivery system using the axle of the cage. By pumping feed through the water in the axle, the fish will remain lower in the cage and reduce tidal flow influence on the feed.

Mortality Removal Without a Diver

Mortality collection through rotation concepts were tested with positive results achieved, giving OOSI valuable information moving forward with respect to future development of diver free mortality collection.

A “trough” proto-type was assembled and installed in the cage. Trials achieved positive results in retrieving mortalities but further construction and design development is necessary. This development is continuing on the iCages™ constructed in Back Bay.

iCage™ Assembly and Engineering Improvements

Techniques for future assembly methods were born from the arch replacement program. OOSI further improved their arch installation methods on its next build, by installing the arch sides to the rings while on the beach. Arch centers were installed at the surface from a boat. This eliminated the need for divers, during arch installation. What took four to five days and four divers at the Hardwood Island build, took one day with no divers, on the next two builds. The confidence to do this was gained from removing and replacing the arches in pieces, rather than whole sections, during the arch replacement program. 

Also, as a result of the arch replacement program, the net design was altered slightly for the next Admiral cages built for Back Bay, to reduce stress on the arches, as well as maximize volume available within the structure. These changes also improved the net drying aspect, as it lifted areas of the net prone to contact with waves, up away from the water slightly. Improved access to the cage, due to closer proximity of the net to the flotation ring was also achieved.

Structural changes to the arch assembly, as a result of the arch replacement program, in specific, the horizontal rib, have led to improvements in a concept related to the installation of a second level of protection. Net panels can be attached between arches by attaching them individually to the horizontal ribs. This rib concept has potential to be applied to the spokes as well, allowing for greater spoke strength, as well as facilitating the net panel installation on the ring sections as well as the arch sections. This will be especially important to move into areas prone to sharks and sea lions. 

Improvements in the vertical arch rib, led to improved attachment of the net to the arch for the Back Bay cages. Holes were drilled and chamfered in the vertical rib, which is now continuous from ring connector to ring connector, through the introduction of “crow’s feet bridges”. The net is now attached through these holes. This eliminated potential chaffing due to boats tying up to the arch centers, as well as significantly reducing the amount of rope required to attach the net to the arch.

Buoyancy Control

Performing techniques such as treatment and fish handling have generally required the adjustment of the flotation ring buoyancy. The experience gained at Hardwood Island has identified areas for improvement, as well potential solutions. Conceptual work related to projects for 2011 was performed at Hardwood Island. Simplified flotation ring buoyancy control projects are planned and currently under development for the Back Bay project.

While it wasn’t resolved at the Hardwood Island project, the tom float airline improvement project saw vital progress in Passamaquoddy. The airline which comes to the surface to allow the surface crew to add or remove air from the tom float, was plagued with issues going back to the Beta Trials. Collapsing hoses, sinking hoses, tangled hoses, and broken fittings, were all things needing improvement. Steps to resolve sinking and collapsing had begun in the Beta Trials, but weren’t proven until Hardwood Island.  Fitting changes for Hardwood proved to be effective. Introducing a back up valve on top of the tom float allowed for manual inflation by a diver with a spare tank in the event of airline failure, was proven to very useful, especially during install. Corks were placed along the airline to make it highly positively buoyant. This was in an attempt prevent the airline from wrapping around the tom float and tangling. The tangled airline had at times gotten pulled through the tom float snatch block when it bottoms out in high tides. This would heavily damage the airline, as well as jam the mooring system, preventing proper motion during tidal movements. These corks did not resolve the situation on their own. While preventing the airline from entering the snatch block, it did not prevent tangles. The corks were, however, an integral part of the current version we are currently proving at the Back Bay site, which is proving to be effective. 

Preliminary testing began with respect to simplifying submergence, through use of increased lift at the tom float. Results from this reinforced the need to pursue a two tom float mooring system, both for simplified submergence, as well as for simplified mooring system installation in deeper water.

Fully Enclosed Bath Treatments

Due to the issues related to using a 100 m treatment tarp on the iCage™ during full tarp treatments, it was determined that a custom built tarp should be utilized, using rotation, in order to eliminate damages due to propellers and bolts, as well as ensure a more accurately estimated treatment volume which is of utmost importance when applying treatments. The concept of having permanent ring tension lines in strategic locations, to allow the net to be released during fish handling techniques, was trialed and proven to be useful. A technique was devised using rotation and flotation attached to the net, detached from arches, to crowd the fish into the upper water column. This was useful to force the fish into the treatment area during open tarp treatments.

Handling Methods

Improved fish handling techniques were investigated. OOSI and AFF conducted a “sweep” of iCage™ 16 at the end of the growth cycle. A trial was conducted using the flotation aspect of the iCage™ in conjunction with a traditional cork line. This trial proved relatively successful and will form the basis for further testing. “Split Links” are being investigated as a method for detaching and reattaching the nets to the cage structure in a timely manner, to facilitate this sweeping method.

Seining trials were successful and identified some areas for improvement to the seine design such as size, weight distribution and materials used. A new seine design has been completed and is now being constructed using Dyneema™ netting for the 2700 m³ cages in Back Bay. Although the improvements in design will be beneficial we believe that repetition will be the key to further development and streamlining of seining procedures.

Ancillary Assessments

This project allowed Open Ocean Systems to assess the ability of the cage to withstand moderate wave and tidal energy. The engineering improvements made continued the development of the use of the iCage™ for eventual offshore farming strategies.

The iCage™ responded very well to the wave energy at the site with very little movement. This is attributed to tension and attachment position of mooring system as well as the lower buoyancy of the cage in comparison to traditional cages.

The iCage™ submersion attribute was tested during a hurricane showing its ability to successfully mitigate negative surface conditions further developing its offshore capability.

The Dyneema™ netting proved to be very strong and durable performing well deterring predators and eliminating escapes. Although results were positive Open Ocean Systems has begun development of a predator determent net that can be placed on the cage seasonally to further discourage predators from mortalities that settle to the bottom of the cage. This development will give greater security to the stock with limited cost.

5) Conclusions

The result of the first objective of the project was deemed highly successful by project management of Admiral Fish Farms and Open Ocean Systems. The Dyneema™ net was placed on the iCage™ on November 15, 2009 and was removed on January 17, 2011. The net was not changed during this period. It took minimal rotation maintenance and two washings of the ring sides to keep the netting free from fouling. When the net was removed there was moderate fouling present on approximately 15 % of the net surface which was mostly the ring sides which are not regularly exposed to the sun and wind during rotation. The fouling consisted mostly of hydra, tunicates and mussels. Ambient oxygen levels were maintained in the iCages throughout the entire project. The cost of net maintenance was reduced from $20,000 for the traditional cages to $4,000 for the iCage™.

The second objective of the project made some milestones but was somewhat hindered by the sea lice epidemic that occurred at the site. Draft SOP’s were developed and final drafts are in development. Open Ocean Systems was able to assess the structural ability of the cage and make necessary improvements in engineering. Working in collaboration we developed better accessibility for routine procedures such as feed camera installation, fish sampling and non-diver mortality removal. 

The biofouling challenges were historically high in Passamaquoddy Bay this year leading to increased net maintenance costs on the traditional cages. There was an extensive reduction in maintenance costs associated with the iCages™ as well as a consistently better environment within the cage compared to surface cages. 

Admiral Fish Farms has moved forward with an investment of two more 2700 m³ iCage™ units at a site located in Back Bay, New Brunswick. These units were constructed and stocked in the fall of 2010. We are continuing with development focusing on two key points: 1) Efficient and timely access procedures; and 2) Fully enclosed tarp treatments utilizing the rotational aspect of the cages and a custom built tarp.

There is full confidence that this AIMAP project has shown us that the technology has the possibility to benefit us on our sustainability path by eliminating the use of copper based antifoulants.

6) Communications

Two presentations have been made by Admiral Fish Farms at government/industry workshops: The Aquaculture Canada Conference (2010) and the Atlantic Canada Fish Farmers Association workshops (2010) involving details from this project and the continuing commitment and investment by Admiral Fish Farms.

Admiral Fish Farms will work collaboratively to communicate to industry and the public the successful results of this innovative project.