Innovative Sustainable Solutions for Canadian Finfish Aquaculture Operations: AEG Solutions for an Eco-Friendly Aquaculture Future

Aquaculture Engineering Group Inc (AEG)

Table of contents

• Project Summary
• Project Rationale and Objectives
• Location of the Project
• Site Set-up & Fish Entry
• Technology Development
• AEG Feeder
• AEG Containment Systems
• Automatic Fish Stock Sizing
• Logistics Mitigation Strategies
• Conclusions & Recommendations

Project Summary

AEG Inc. was incorporated in November 2002 to develop equipment and management solutions that meet existing technology shortcomings. AEG Solutions have been developed individually, model tested and prototype trials completed. This AIMAP project allowed the first ever complete integration of the advanced AEG Feeder and AEG Containment Systems while including fish on a commercial very high-energy grow-out site in St. Mary’s Bay, NS. Smolt availability prevented full stocking of the site as originally planned but a lower number of smolt were entered to allow monitoring of fish welfare with the equipment. Further technology development occurred during this Phase I project including proof-of-concept of a submersible HDPE collar that saved the equipment/fish from ruin in February 2009 when heavy ice passed through the site and integration of the AquaSonar fish sizing technology with the AEG Feeder to measure fish size on a regular basis. AEG continues to develop logistics mitigation strategies that increase farm safety, fish welfare, and cost-effectiveness. A primary example of this from Phase I involve the new AEG nursery net system that effectively concentrates small
smolt for better fish and feed management during the early days following sea cage entry while increasing survival by providing a more protected environment even in the open ocean. Completed activities in Phase I will continue to be monitored during Phase II as these technologies support our activities to raise fish on this established high-energy site in the Bay of Fundy. Value engineering, environmental and economic evaluation, AEG
Solutions demonstration, and new product development as necessary will continue and be the focus of Phase II activities.

Project Rationale and Objectives

For 12 years, AEG proponents operated a very successful commercial Atlantic salmon aquaculture company in the Bay of Fundy region that produced 5,000 metric tonnes annually when the company was sold in 2003. This extensive experience of actively raising fish in sea cages provided AEG with a solid understanding of the technological and management limitations presently experienced by the global finfish aquaculture sector. In response, AEG was incorporated in November 2002 to develop innovative solutions – AEG Solutions – to limitations impeding further sustainable growth of the finfish aquaculture industry worldwide.

AEG Solutions were originally designed for use predominately in high-energy open ocean environments. To this end, individual products have been professionally engineered and model tested at the National Research Council Institute for Ocean Technology in St. John’s, NL in simulated high-energy conditions prior to fabrication and field-testing of commercial-scale prototypes.

• The AEG Feeder is designed to provide water-borne delivery of feed thereby maintaining the feed delivery pipes well below the active ocean surface. The AEG Feeder is capable of ‘meal feeding’ cages similar to all other centralized feeders available globally or using feed boats but also the onboard hydraulic/PLC system control is now programmable to provide ‘pulse feeding’ capability where up to 28 cages can be fed simultaneously. Initial programming had been completed to allow ‘pulse feeding’ but the benefits associated with this feeding strategy had never been documented in sea cage trials.
• AEG Containment Systems combine surface logistics strategies common in the aquaculture industry with subsurface mooring connections that are increasingly integrated in novel ‘offshore’ cage designs. The AEG Containment System design progressed through several iterations prior to the start of this AIMAP project but never evaluated to raise fish.
• AEG has developed an advanced site data management software program – Neptune – but debugging this application with real site data was not completed before this AIMAP project. Further, Neptune has one module capable of continually predicting fish size over time and the eventual harvest date based on a feed rate and assumed FCR. The full potential of this program will be realized if automatic fish sizing data can also be imported so that real-time fish size data is compared with predicted fish sizes over time. These comparisons will allow feed rate adjustments to maintain anticipated harvest schedules to meet market demands. Further, ongoing collection of fish size data coupled with collected feed quantity data will allow continual calculation of FCR and therefore better feed management and reduced environmental impact.
• The chosen site for this project experiences very high energy – 70 knot winds, 4 m waves and 1.8 knot currents – on a fairly regular basis. The site also receives ice flows in February resulting in severe site damage and fish loss on more than one occasion in the past. AEG used this AIMAP project to develop a proof-of- concept submersible HDPE collar to avoid the ice flow and other surface based perils.
• AEG Solutions as described have never been fully integrated on a single commercial aquaculture site for performance evaluation and monitoring. This specific AIMAP project enabled AEG to complete this necessary integration step within a commercial scale operation to raise fish at a commercial stocking density. Operating AEG Solutions in an integrated manner will also allow development of additional logistics mitigation strategies and technologies as necessary to ensure cost-effective operations are possible.

Location of the Project

The project was conducted on finfish aquaculture site #1012 in St. Mary’s Bay, NS to complete the activities of this AIMAP project. The site offers many challenging attributes that will demonstrate the full potential of AEG Solutions to raise fish in higher than normal energy but also represents an excellent opportunity given the size of the site (19.5 ha), continuously flushing current to oxygenate contained fish and clear farm wastes, and relative isolation from other aquaculture operators.

Aquaculture Site #1012 is located near Tiddville north of Petite Passage along the southeastern shore of Digby Neck. The nearest wharf for site maintenance is 3.22 km northeast of the site in Little River. AEG pays regular wharfage fees in Little River but also in Sandy Cove, which is located further north but has greater wharf capacity to hold vessels overnight and during storms.

The site is close to shore and protected in the general N-NW direction. However, this is the extent of protection on this site with very long fetches present from the NE (up St. Mary’s Bay) and SE-S-SW (mid-Atlantic exposure) directions. Additional care must be taken to moor any aquaculture infrastructure on the site as the wind can occur for prolonged periods of time and the ensuing waves can be severe and damaging. Current on the site is regularly moving at 1.5 knots while extreme running tides can reach 1.8 knots.

Site Set-up & Fish Entry

The AEG AIMAP project site was established in Fall 2008. The original plan was to enter 375,000 smolt in 5 AEG Containment Systems coupled with the existing AEG
100MT Open Ocean Feeder. However, there is a recent smolt supply bottleneck in the local aquaculture industry and AEG managed to only acquire 225,000 smolt for entry in Fall 2008 from two separate hatchery operations. These smolt were entered in November/December 2008 after the AEG Containment System with nursery nets were securely moored onsite.

The bulk of these smolt (175,000) were sourced from a single hatchery and virtually all died within the first 45 days following entry. The reason for this high mortality rate is unknown but speculation is that either the smolt were too small (50 g average) for this high energy site or the fish did not properly smoltify prior to seawater entry. The remaining smolt (50,000) also had a high mortality rate but sufficient numbers survived through Winter 2009 to allow the initial observation of fish within the AEG Containment Systems, during submersion, and first feeding using pulse feeding control.

The surviving smolt came from a hatchery with known background BKD (i.e., known exposure to BKD but with no clinical signs of the disease). Additional smolt were sourced for Spring 2009 and so the existing fish on the site were eventually removed to eliminate any opportunity for a BKD outbreak on the site and infection of a higher number of new smolt anticipated for entry in May 2009. Unfortunately, the hatchery experienced internal issues and the anticipated smolt died before saltwater transfer thereby eliminating any possibility for AEG to acquire new fish and therefore leaving our site empty of fish through Summer 2009. Site personnel used this opportunity to develop better ways to integrate the AEG Feeder and AEG Containment Systems, further refine the submersible collar concept, and fully integrate the AquaSonar fish sizing technology. Surplus trout smolt were eventually available for entry in Fall 2009 and approximately 220,000 smolt were entered into two nursery nets in November 2009 for continued grow- out to harvest in Fall 2010 as part of Phase II of this AIMAP project.

This ongoing fish situation meant that Phase I of the AIMAP project (effectively September 2008 – March 2010) was focused mostly on technology development and integration while fish sizing and comparative data collection between meal and pulse feeding will continue to be the focus of Phase II of the project (effectively March 2009 – October 2010).

Technology Development

Modern finfish farming, such as that operating in Canadian waters to raise Atlantic salmon, began a little over 35 years ago in Norway. Norway continues to play the “model farm” role and Canadian aquaculture finfish companies are inundated predominately with Norwegian technology that was developed for the relatively benign Norwegian fjord environment. While these technologies work well in Norway they tend to be generally sub-optimal for use in the more robust Canadian environment.

In 2002, AEG was incorporated to develop technology and management solutions that are capable of safe, efficient and cost-effective operations in medium- and high-energy environments while remaining cost-competitive for low-energy environments. The AEG product portfolio is driven by innovation while our design philosophy requires that all AEG Solutions must meet five sustainability criteria that ensure products are:

• Socially Acceptable – Products must help to mitigate social issues frequently associated with marine aquaculture operations. Example social mitigation resulting from deployment of AEG Solutions include: integration with other users including wild fisheries, noise control from marine aquaculture operations, and increased worker safety while working in exposed oceanographic conditions.
• Cost-Effective – Products must be cost-effective in terms of economic feasibility, ease of deployment, decreased maintenance effort, extended life-expectancy, and compatible with some existing farm infrastructure and operations to decrease potential disruption following adoption.
• Eco-Friendly – Products must help to reduce the environmental impact associated with operational footprint, benthic nutrient loading, and escapee interactions with wild fish stocks, among other environmental issues.
• Focused Design – Products must be appropriately designed from an aquaculture perspective and to provide value engineering for our clients. Marine aquaculture investors today are becoming increasingly sophisticated and demand assurances that all necessary engineering analyses and third-party verification are completed before products are available for purchase. Our approach provides the best value for operator investment while instilling confidence and trust in AEG Solutions.
• Robust for Survival – Products must allow marine aquaculture expansion to locations having medium- to high-energy with respect to waves and current, although AEG Solutions are equally suited for deployment on protected nearshore sites. Further, the fish stock must also be able to survive the same conditions for farm success and therefore fish welfare is considered during product design.

AEG has been developing its component technologies since incorporation but integration of these technologies to work on a single site and in the presence of fish had not occurred prior to this AIMAP project.

AEG Feeder

Virtually all existing feeding equipment, in feed boats or centralized feeders, use air
blowers to distribute feed. Air blowing can result in significant feed breakage and the broken feed and/or dust is generally uneaten therefore affecting site FCR and adding considerable cost to the site operation (this cost can be as high as ~$350,000 per
1,000,000 fish raised through a grow-out cycle) and unnecessary environmental loading. Air blowers also create considerable noise pollution during feed delivery and result in a fish boiling behaviour that further adds to the total site noise impact. Noise pollution can result in unnecessary social conflicts with upland homeowners especially during weekends and holiday site operations.

The AEG Feeder uses an innovative water borne feeding technology that is less aggressive on feed pellets thereby minimizing feed breakage and subsequent costs and environmental loading. Further, hospital grade muffler systems are integrated to eliminate noise pollution and fish boiling behaviour during feeding and associated noise is completely eliminated. An animation is available on the AEGSolutions Youtube Channel illustrating generally how the AEG Feeder works (http://www.youtube.com/user/AEGSolutions?feature=mhw4#p/u/2/T1fL8Xtw47k).

In addition to water borne delivery, the AEG Feeder programming and PLC control offers enhanced versatility in site feed management. Seven feed pipes can be used within each onboard feed system. The deployed AEG 100MT Open Ocean Feeder has four onboard feed systems and therefore capable of feeding 28 feed pipes. The AEG Feeder versatility allows three general modes of operation:

• manual control whereby an operator might sit on the deployed feeder or within a distant office and dispense feed while monitoring a feed camera mounted within each cage similar to the use of feed boats or other air delivery centralized feeders;
• programmed to operate automatically using ‘meal feeding’ whereby each cage stock is offered the entire meal allotment, as determined by the site water temperature and a percentage of established feed table calculations based on fish biomass, before the next cage is meal fed in succession; or,
• programmed to operate automatically based on a percentage of feed table allocation but with all cages on the site fed simultaneously through ‘pulse feeding’ whereby a portion of the total meal allotment is given to each cage in succession until the entire meal is fed. This level of automatic control allows fish in sea cages to continue hatchery-style feeding that they have become accustomed to prior to transfer to sea.

AEG previously automatically fed a couple of commercial cages using its 100MT Open Ocean Feeder in ‘meal feeding’ control. However, ‘pulse feeding’ of cages with the distributor arm rotating on a continuous basis to dispense feed within each feed pipe in succession had not previously been accomplished until this AIMAP project. AEG accomplished this level of pulse feeding control during Phase I of this project and now confident of its capability to continue feeding the fish in Phase II. A recent video is also available on the AEGSolutions Youtube Channel showing fish feeding on the site using the AEG pulse feeding method of feed provision (http://www.youtube.com/user/AEGSolutions?feature=mhw4#p/u/3/KH2IM5aYv2E).

Note that in the feeding video the fish are virtually fed at the surface but there is no aggressive behaviour during feeding, fish stress is completely eliminated during feeding, no noise pollution during feeding, and there is very little size discrepancy within the contained fish population. All of these positive outcomes are attributed to the hatchery- style of feeding provided to the sea cages with each meal being dispensed over an extended period of time (upwards of three hours in this case) and each pulse of feed provided within 1 minute of the previous pulse.

AEG will continue to develop feeding protocols with its advanced water borne delivery system in Phase II of this project by comparing pulse feeding and meal feeding with regards to FCR and growth rates through harvest.

Integration of the AEG Feeder with sea cages was rather awkward in previous applications as host companies frequently requested that the feed pipes come to the surface and go over the collar float pipes to enter the cage. While this approach worked it somewhat removes the advantage of the AEG Feeder for use in high energy environments where the feed pipes would never have to be exposed to surface wave activity. Project personnel experimented with several means to integrate the AEG Feeder feed pipes with the cages without ever exposing the feed pipes to the surface. We finally settled on a double flange set-up with a separate short feed pipe positioned within the cage and bolted to the long feed pipe extending from the AEG Feeder.

AEG Containment Systems

Commonly used Atlantic salmon cages comprise of a net hanging within a collar that is permanently positioned at the surface and tied directly to the mooring grid. This approach requires a large footprint for the sprawling mooring system and results in frequent kinking damage to the surface collar and violent net movement during storms that can result in fish loss. Further, traditional cage arrangements use weight balls or weight rings that are usually grossly underweighted in the site current resulting in exaggerated net bagging/folding and associated loss of volume and increased fish stress, damage and mortality.

There have been a few novel cage concepts designed for use in medium- to high-energy environments. It is imperative that any new cage system contemplated for Atlantic salmon farming, or any other eventual commodity species for that matter, be cost- competitive with existing cage systems used in the aquaculture industry (presently salmon cages can be moored for < $10/m3) and do not depart significantly from generally accepted logistics mitigation strategies used in the industry. Salmon farm operators are used to having open access to the fish stock through surface-based HDPE collars that enable ongoing logistics associated with fish sampling, medication, inspection and harvesting.

The AEG Containment System was conceptually designed after years of operating an exposed high-energy Atlantic salmon site in the Bay of Fundy. The primary innovation in the AEG Containment System is that no mooring connections occur to the surface collar but all cage-to-cage and cage-to-mooring connections occur through the enhanced AEG Weight Ring. The enhanced weight ring maintains its overall geometric shape through inclusion of a series of spoke lines that extend from the weight beams to a central location in the middle of the bottom net, similar to spokes in a bicycle wheel. This strategy eliminates all point loads to the collar while providing a constant growing volume that greatly enhances fish welfare even in high currents and wave energy. AEG Containment Systems have been developed and field tested prior to this specific project but never to hold fish and raise the stock to a harvest size as proposed in this AIMAP project.

The site experienced several tropical storm fronts during Summer/Fall 2009. The AEG Feeder takes a picture of the site every 15 s and records these images for later evaluation as necessary. The collar handrail is nearly fully submerged illustrating the importance to include a top net that is also constructed of smolt net mesh to ensure fish retention during storms while using the AEG Containment System. Another significant storm event was documented in early March 2010. Images from this storm were again captured by the AEG Feeder and 1 hr of 15 s images was recently compiled into a video and can be viewed at the AEGSolutions Youtube Channel (http://www.youtube.com/user/AEGSolutions#p/a/u/0/ACXpRA-s99g).

As a side note, feed pipes are extending from the AEG Feeder to the AEG Containment System during this storm to feed the contained smolt. The blue buoys evident in the pictures provide the site operators with a visual indication that the feed pipes remain together during and after storm events. No scheduled feedings were missed during any of these storms, which would have otherwise disrupted feeding for at least 4-5 days per storm if feed boats were used on this specific site.

The behaviour and performance of the AEG Containment System is also benefiting from presence of a submersible HDPE collar that was developed has part of this AIMAP project. Offering HDPE collar submersion capability globally will offer farm operators an ability to effectively avoid many damaging surface perils including typhoons/hurricanes, algal/jellyfish blooms and seasonal ice flows to name a few but without the added capital expenditure to acquire expensive novel offshore cage designs. Further, there is increasing discussion that submersion of Atlantic salmon to just 4 m depth can potentially reduce sea lice infestation.

Submersible HDPE collars have been accomplished in the past with limited success. The main limitation with this product from other suppliers is that the cages are held spatially using bridles extending from mooring grid plates to the HDPE collar. Presence of these bridles limit the ability of the collar to submerge to depths necessary to avoid storm surge energy and ice avoidance by the mooring grid is not possible. The AEG Containment System is moored through the enhanced weight ring and therefore the prospect of a submersible HDPE collar is much more appealing.

Submersion proof-of-concept while using the AEG Containment System was completed using two main design criteria to accomplish this activity:

• Submersion of the 3-ring 315 mm HDPE collar must be controllable and still accomplished for an entire site within 1-2 hours to avoid pending surface perils such as ice flows, algal blooms or significant storms. The same control must be provided to raise the system or risk losing the fish stock.
• Partial submersion of the collar while remaining at the surface was desirable to increase system transparency to passing waves during Fall/Winter/Spring storms. This design criterion employs similar principles as the ocean going shipping industry while using ballast water lines.

The general guiding principle for submersion is to ensure that the entire cage system is negatively buoyant to submerge while the HDPE collar must remain positively buoyant even during submersion or it will continue to sink and collapse the net onto the fish stock. The basic design of the AEG submersible HDPE collar involves a series of appropriately placed valves and bulkheads within each pipe of the 3-ring collar. The collar pipes are filled with water by opening specific valves to submerge the cage system. The entire system will continue to sink unless either of the following strategies is deployed to maintain the cage at a specific depth in the water column:

1. If sinking depth is to be maintained on very deep sites and in the absence of surface ice flows then a series of large buoys will be connected to the enhanced weight ring with their chains passing between the middle and outside collar pipe. The length of float chain will dictate the depth of cage submersion from the surface.
2. If sinking depth is to be maintained at a relatively shallow site where ice flows represent the significant surface peril to be avoided then the surface buoys would not be used but the length of chain extending between the enhanced weight ring and attached barrels will dictate the distance of submersion from the seabed.

Proper placement of bulkheads within the collar pipes ensures that the system can sink in a very controlled manner with no risk that the collar might invert itself or tear the nets during the process. Raising the system is accomplished by pushing compressed air through a manifold into the HDPE collar and forcing the water out.

Construction of our first proof-of-concept submersible HDPE collar was completed and field tested in December 2008. Timing for its completion was critical as the site frequently experiences heavy ice flows in February of each year. This situation was no different in 2009 as thick ice moved out St. Mary’s Bay and filled our site. The submersible collar was used to submerge the AEG Containment System with smolt prior to the arrival of this ice flow and remained submerged for 9 days. The entire site was re-established at the surface when the ice flow cleared from the site by moving further out of the bay and no damage was reported to the system. This was not the same outcome in the past when ice caused significant damage on at least two other occasions.

AEG also used this project to visually monitor the loads experienced on the AEG Containment System on this high current aquaculture site compared with measured loads previously collected in tank trials at the NRC-IOT facility in St. John’s, NL. The main net was initially deployed having a total net depth of 15 m (14 m net depth in the water) on a 125 m circumference collar. The system experienced significant forces especially during the running ebb tides. The project team eventually decided to remove 4 m of net depth (leaving 10 m net depth in the water) to reduce the system forces and associated strains.

Automatic Fish Stock Sizing

The AEG Feeder records the quantity of feed provided to individual cages each day and
sends this information to operational managers via email in daily feed reports that are reviewed prior to automatic entry into the AEG site information database – Neptune. Having daily fish size measures coupled with the already available feed data would provide immense opportunity for farm operators to better manage feed inputs, maximize FCR and growth, and predict harvest schedules.

There are basically three methods available in the marketplace to size individual cultured fish:

1. A submerged frame that requires fish to swim through it to break a net of infrared light beams. This captures the silhouette image of the fish to calculate its size. Time is the primary limiting factor with this technology as a sufficient number of fish must swim through the frame to gather an adequate sample for biomass estimation.
2. Uunderwater images of fish to estimate the total stock biomass. This method
   is less invasive to the fish population but more labour intensive to quantify the fish sizes by requiring data post-processing back in an office after images are acquired. This approach is also limited to sites and times of day having higher visibility and light conditions so that fish imaging is possible.
3. Sonar technology to capture fish size data by placing a small transducer in the cage with the fish population. There is no time consuming data post- processing required and the technology is not limited by visibility or light conditions.

AEG previously signed an MOU with the supplier of a sonar technology available in Newfoundland – AquaSonar – giving exclusive rights to directly integrate AquaSonar data within the AEG Feeder. This integration will provide immediate use of fish size data to adjust feed amounts and provide greater control of feed management. Further, actual fish sizes can be compared with predictive growth curves within Neptune to potentially provide superior harvest and market planning.

The AquaSonar is presently sold as a portable unit that is intended for short-term deployment within each cage so that an entire site can be measured over a 1-2 day period. Typically the operator would set the unit up at cage side, sample for a few hours in an individual cage by deploying the transducer, then retrieve the unit for redeployment in another cage. The AquaSonar unit calculates all fish sizes to reduce data post-processing.

The project AquaSonar units required some hardware and software redesign to allow evaluation as planned. The units were outfitted with customized wireless communication capability through a WiFi connection to retrieve data from each unit. AEG personnel designed and built a water tight enclosure to house each AquaSonar unit so that it can be permanently mounted to the cage collar. A removable rechargeable battery pack powers the AquaSonar. The battery is replaced as necessary with another charged unit to continue fish sizing.

The AquaSonar unit is programmed to sample for fish sizes daily over several hours and is capable of storing several days of data. The existing computer onboard the AEG Feeder uses the supplied wireless connection to retrieve the fish size data from the AquaSonar. The AEG Feeder operator presently connects remotely to the feeder computer from a land based office and manually retrieves the data from the AquaSonar through the wireless link. Automatic retrieval of the data from the AquaSonar unit, similar to automatic feed data retrieval, is possible but will require a redesign of the AquaSonar interface software and could represent a next logical step to complete integration following success during this initial evaluation.

The AEG Feeder operator reviews the fish size data manually to check data validity and watch for trends that might cause alarm. The daily fish size data would be used to update Neptune and make any recommended adjustments to the onboard feeding program. Harvesting plans can be better predicted if measured fish sizes are compared with predicted growth curves. AEG has developed a business planning module of Neptune that continues to be coded for widespread distribution and sales. Any specific day of the predicted growth curve can be highlighted to provide the predicted fish size on that date, which can be compared with retrieved fish size data. Discrepancies can be noted and feeding rates altered in the AEG Feeder computer should the operator wish to maintain the planned growth/harvest schedules.

Utility of the AquaSonar fish size data to predict and maintain growth and harvest schedules will be monitored throughout Phase II of this project. The first test of collected AquaSonar data and its utility will occur when the water temperature warms to at least 5C so that a sample of fish can be taken and weighed. Fish sizing will continue throughout the summer by seining and measures compared with AquaSonar data.

Logistics Mitigation Strategies

AEG continues to improve logistics mitigation and document these strategies so that
buyers of AEG Solutions can benefit from our own operating experiences. This project objective is essential to AEG success as our present efforts represent the first time that AEG Solutions have been fully integrated on a single site to raise fish through harvest.

The most significant logistics breakthrough to date involves design and integration of the innovative AEG nursery net system. This improvement in fish husbandry was quite serendipitous. At the start of the project, personnel were preparing the site to accept 225,000 smolt that should have been entered within three separate cages. However, only one collar was refitted to allow submersion and we were fully expecting that heavy ice flows would pass through the site in February 2009. The traditional strategy might have been to triple stock this single cage and later split the stock into three separate cages.

Taking a fresh look at the situation and the more robust structure offered by the AEG Containment System we gradually developed a plan to integrate a nursery net system whereby individual 50 m nursery nets would hang from more robust top net stands and tie into the same enhanced weight ring offered by the AEG Containment System. Up to three individual 50 m nursery nets can comfortably fit within a single 125 m AEG Containment System.

Nursery nets offer marine site operators much greater control over fish and feed management compared with the standard operating procedures frequently used today in the wake of major disease outbreaks such as ISA. Smolt are stocked in hatcheries at a rate of 30-40 kg/m3. Present sea cage stocking strategies enter the required number of smolt into each cage such that the harvest stocking density is at most 20-25 kg/m3. However,
this requires that smolt are taken from their hatchery tanks at ~ 30 kg/m3 and placed in large sea cages initially at < 0.5 kg/m3 and raised to the harvest 20 kg/m3. Use of smaller integrated nursery nets increases this initial sea cage stocking density ten-fold to ~ 5 kg/m3. This is still not very high compared to the hatchery stocking density but certainly much better for the fish stock. Further, feed management in the early days following fish entry to sea cages should be much better as the fish stock are much more localized within a nursery net and therefore should be much better at sourcing provided food, especially while using an AEG Feeder with its centrally located feed diffuser in the middle of each nursery net.

Integration of nursery nets will be suggested standard operating procedures for all AEG Containment Systems sold in the future. This strategy required minor redesign of the main net that must now include soft eyes inside and outside at the bottom of the net sides so that the main net can easily be tied to both the enhanced weight ring and internal nursery nets.

Conclusions & Recommendations

The ongoing shortage in smolt supply experienced during Phase I of this project was indeed frustrating to AEG. Partnering with a commercial farm operator might have addressed this bottleneck but commercial operators would be reluctant to proceed with much of the activities completed during Phase I including AEG Solutions integration, new product development and field trials in high energy environments that were accomplished during Phase I.

There is also a silver lining to having fewer smolt available during Phase I. In the absence of a fully stocked site, AEG personnel could focus very heavily on completing the product integration and development with fewer iterations. This would not be possible if high numbers of smolt were also present as much of the farm personnel attention would then have to be concentrated on fish welfare and husbandry that would have distracted from the product development and integration needs.

Phase II of the overall project continues with fish already entered on the site. These fish are doing quite well, growing and feeding to provide an excellent FCR, and to date demonstrating a higher than expected survival through Winter. Biological data associated with these fish will be reported within the Phase II report in October 2010. This data will include the performance of the fish (growth, FCR, survival) while being raised with integrated AEG Solutions along with the performance of the equipment itself to cost- effectively raise fish in a very high-energy environment in the Bay of Fundy (pulse vs meal feeding comparison, utility of AquaSonar data to continually verify predicted growth rates, fish welfare within the AEG Containment System).