Deep Water Mussel Aquaculture Development (Phase II) Final Report

Norlantic Processors Ltd

Table of contents

• Executive Summary
• Completion of Work
• Review of Project Objectives
• Project Conclusion
• Usable Water Column
• Floatation Issues
• Work Platform

Executive Summary

Mussel aquaculture is a green, environmentally friendly form of aquaculture. Mussels feed on plankton life which grows and blooms naturally in the marine ecosystem. There are no additives to fresh mussels, no antibiotics, no chemicals of any form. However,  shellfish  including  mussels can  become contaminated from human and animal waste products, and locating mussel grow out sites away from such possible contaminants  is important.

In light of this fall's recent shellfish shutdown in much of the Maritime Provinces due to excessive rainfall and run off, it has become apparent that deep water sites might play an even greater industry role in creating a stable shellfish supply than previously thought. At present much of the existing shellfish supply is located near river mouths, estuaries, harbours, and shallow bays where land run off can be excessive in times of significant precipitation. These areas have a greater chance of contamination from bacteria and toxins than deeper sites that are often located further from population centers and the marine features mentioned above.

Phase I of this project showed great promise as Norlantic was able to submerge mussel lines at depth to avoid the perils of the sea conditions associated with the winter and spring months in the North Atlantic. Norlantic grew, submerged, and raised mussel lines in a site that posed great challenges with respect to the natural environmental conditions of the site.  Phase II  was the  actual step  toward  early commercialization of the deep water site and there  were a number of infrastructure and capital investment obstacles that  had to  be overcome, as well  as additional information  which needed gathering and analysis.

Norlantic proceeded with Phase II of the deep water, mussel growing project during the 2008-09 time period completing the project in July of 2009. Capital investment in innovative equipment and other expenditures were made in accordance with the Contribution Agreement between the Government of Canada, Government of Newfoundland and Labrador and Norlantic Processors ltd.

During the winter of 2009 within a couple of weeks of submerging the mussel lines, during a line monitoring trip, Norlantic noticed that all lines had sunk to the bottom. We were initially unable to retrieve the lines due to bad weather and then poor ice conditions. This hampered our attempt to determine what had gone wrong and all we could do during the winter was speculating on the cause. However, in late spring when we retrieved the first line it became obvious that for some reason the floatation had failed causing the entire line to sink to the bottom.

After finally retrieving all four lines (over a kilometre in length each) it became obvious that some of the floats ruptured outward while others collapsed inward. The inward collapsed floats are easily explained as they were most likely squeezed by water pressure to the point of collapse as they sank. It's the floats that ruptured outward that need more investigation, and Go Deep International has begun their investigation process.

For the  submerging of  lines in the  future,  we must  come  up  with  a better  alternative  and  floats constructed of a more flexible material might be the solution. However, no work has been done on this type of float and in depth investigation required.

The newly installed equipment of the work platform performed as hoped and the addition of floatation and the bow thrusters made the platform much safer to operate under harsh conditions. Without these modifications and additional equipment, operating a deep water site in an exposed setting would be next to impossible.

In addition to Norlantic's own efforts at gathering data, we would like to thank Derek Mouland from the Department of Fisheries and aquaculture for gathering and providing a significant portion of data used in this report. In particular we thank Derek for the Station data gathered from Mouse Island in September and November of 2008, and in July of 2009.

Completion of Work

In late August 2008, Fab-Tech Industries Inc. of Glovertown, NL, were commissioned to begin the process of designing and building the equipment that was needed to carry the project forward. The original plan was to have all equipment and the work platform modifications completed by early November. However, due to the later than anticipated start of the project, and some pressing matters on the farm site, some of the work couldn't be completed until April when the barge was dismantled and transported to Glovertown for final modifications.

Norlantic began the process of pouring the concrete anchors that were needed for the project. A limited number of anchor moulds and the onset of sub zero temps in the fall of 2008 pushed back the completion of the required anchors until the spring of 2009. Anchors were borrowed from other Norlantic farm sites in order to prepare and properly anchor the mussellines at the Mouse Island -Tea Arm site for the winter. Materials for the mussel sock and collector long lines were procured and mussel lines were manufactured by Norlantic employees during the August to October period and prepared for deployment. All lines were deployed on time during the fall of 2008.

Temperature and plankton monitoring began in August and continued until the completion the project period. Plankton and temperature data collection began in late August and were done periodically as weather and sea conditions permitted. Lines were deployed during the fall and early winter of 2008 and sunk during the December-January period. Shortly after all the lines were sunk we began monitoring, and it was noticed that many of the lines had quickly sank and gone to the bottom. We did not initially understand why the lines had gone down, but we did know that the lines must have experienced catastrophic failure with the whole line, a kilometre long, sinking to the bottom.  At this point we can not be certain what caused the lines to fail, but we do know that once a line started to sink the floatation most likely failed in succession causing whole line to sink to the bottom. Due to poor sea conditions and ice we were unable to begin retrieving the lines until the spring.

The failure of the floatation has given us great cause for concern and we must therefore reassess either the method and design of the lines, or the design and material of the float,or both. What has become obvious is the need to study this in more detail as the line failure rate was 100%, a complete contradiction to the winter before. During the winter of 2007-08 after all lines were submerged they remained buoyant and the lines were easily recovered in the spring, with the exception of some tangled sections. This past spring and summer the lines in question were extremely difficult to recover as they were not identifiable on the sounder while they lay on the bottom. In order to retrieve the lines, Norlantic had to drag the bottom with a grapple in an attempt to hook the line. This isn't always easy as most of the lines are now resting on the bottom in 300+ feet of water, with some sections of the bottom being muddy and more being rocky. The general vicinity of the lines are well known, but actually trying to hook something at such a depth is quite difficult  considering it isn't identifiable  on the sounder and there are many rocks on the bottom that impede our effort to hook the lines.

Recovery of the lines began in May and continued through the summer and into the fall of 2009. Not all lines had been recovered at the time this report was compiled September - November of 2009 and work in still on going. What we have been able to determine by the floats that have been recovered is that some floats collapsed while others seemed to rupture, or explode outward.

Go Deep International, the supplier of the floats, has been notified of the problem and they have begun investigating the potential source of the problem. We can not be certain at this point, but we believe that perhaps some of the floats were faulty, faulty in terms of the material, or perhaps in terms of pressurization.  It appears that some of the floats ruptured, exploded outward, when submerged to a depth of 40 to 50 feet, an additional 1.2 - 1.5 atmospheres of pressure, and hence caused that section of line to sink. As one section of the line began to sink, the entire buoyancy of the line was affected and the entire line was dragged down. Those floats that didn't rupture were crushed by the immense pressure (as much as 10 atmospheres) as the floats began to descend. As the line sank deeper and more floats crushed losing buoyancy it began a chain reaction that saw the full kilometre long line sink to the bottom to a depth of approximately 300 feet or more. At this depth all floatation had collapsed causing an entire loss of all attached floatation.

Upon retrieving some of the lines it was easy to see that some of the floats had ruptured and that some had been crushed. None of the floats were re-usable; all floats attached to the lines were rendered useless. The entire purchase of floats was lost as was a significant amount of the product on these lines.

Review of Project Objectives:

In addition to the overriding goal of this project, which was to bring deep water mussel aquaculture into commercialization, there were three priority project objectives for Phase II of the "Deep Water Mussel Aquaculture Project" and they were as follows;

1. Develop new and innovative equipment to operate on a floating work platform that would aid in handling  the  tremendous  size and  weight  of  the  gear  required  for  deep  water  mussel aquaculture.
   
   This objective was accomplished. The equipment was manufactured and installed on the platform by Fab-Tech Industries. The equipment has performed well and increased the safety of those working on the platform. There hasn't been any difficulty in setting or pulling up the lines. Even the huge anchor weights are easily manipulated with the equipment on the work platform; in particular, the capstan and the crane have made manoeuvring the huge weights and lines much more manageable.
   
   The reclaim hopper and conveyor do work effectively when pulling collector lines. In the past a great deal of mussel seed was always lost when lines were pulled in the conventional manner. By keeping the head rope and foot rope of the collectors lines separated very little seed is lost due too rough handling.
   
   The thrusters have added a couple of dimensions to the work platform. First, it enables the crew to keep the platform stationary while wind and sea conditions would have made it difficult to do any harvesting. Second, the thrusters have provided an added degree of safety as the vessel doesn't drift across lines during the harvesting process.
   
   
2.  Modify the mussel long line sinking system to avoid the rope tangle problems and handling difficulties.
   
   During Phase I of the project, line tangles were a major problem. It was hoped that the addition of smaller weights between the large 3000 lb weights would aid in preventing the line from moving due to drag from the current. Although Norlantic added more weight at smaller line intervals in an attempt to inhibit line movement and hence tangles, it was difficult determine how successful this effort truly was because all lines experienced catastrophic failure. The mussel lines sank to the bottom and all floats either collapsed from the extreme pressure or ruptured and then sank. Having the lines sitting on the bottom in over 300 feet of water makes it impossible to assess the effectiveness of the additional weight. We are still trying to determine the exact cause of the float failure, but the failure of just a couple floats on a line can, and most likely did, start a chain reaction of the lines sinking and hence more and more float failures.
   
   
3. Determine the extent of the usable water column.
   
   It would have been much better if we were able to keep the mussel lines afloat in order to do a proper analysis of growth rates and meat yields. This defiantly would have helped us to better understand the extent of the usable water column. However, we can now only use gathered data to help with determination of the usable water column. The two greatest factors in determining suitability of a water column for mussel growth   is temperature and food availability. Mussels grow very slowly at temperatures  below 3°C,or above 20°C, and mussels grow best when plankton (measured by chlorophyll a) levels are >1ug/L.
   
   Optimum temperatures and plankton levels for mussel growth exist for periods of time during the course of the year. However, here in Newfoundland we seldom experience more than five to seven months of optimum growing time where both plankton and temperatures are both in the ideal range. The levels of plankton and temperature of the water column do vary somewhat depending on the depth and it was our objective to determine the depth of usable water as well as the optimum depth for growth. During the balance of the year we see temperatures and plankton levels that will sustain the mussels, but growth occurs at a much reduced rate.

Project Conclusion

Usable Water Column:

Based upon the temperature and phytoplankton data for the Mouse island site AQ 964, it appears that the upper 20m is the most productive for mussel growth. In particular there are seasonal variations that make the 10- 20 m section of the water column perhaps the most prolific in terms of food availability. This section of the water column appears to consistently have higher levels of plankton than either the upper or lower levels. There are some periodic variations where food is abundant in depths as shallow as 2 m, but these are generally very short lived and usually occur during periods of significant fresh water mixing which generally occurs for a period during the spring and again in the fall.  At and below the 25 m level, chlorophyll a levels only spike above 1ug/lfor the July-August period. Between 10 and 20 m we see levels of chlorophyll a generally at or above 1ug/lfor the months of March-May, July­ October and again for a short period around December.

Temperatures vary significantly depending upon depth, but what has become obvious is that there is less fluctuation at depth. The entire annual range of temperature at a depth of 25 m is approximately 7°C with a low of 1°C and a high of 8°C. These temperatures aren't prohibitive to mussel growth, but they never hit the ideal temperature range of 10 - 20°C. The shallower depths, particularly those above 10 m often experience a super chill in winter and spring where temperatures drop below 0°C. These extremely cold temperatures prohibit growth and can at times be fatal to shellfish.  In general, the water column between 10 m (33ft) and 20m (66ft) appears to be the most conducive for mussel growth.

It is important to note that although the lines had all sunk to a depth of 300+ ft and remained there for up to 7 months, a significant portion of the mussels survived, approximately 50%. The other 50% was most likely lost due to preditation while the mussels were on the bottom, making them easy prey for other creatures like starfish and crabs.  In addition, mussels that sank into muddy areas also died due to suffocation while sitting in the mud for an extended period. Many of those mussels that sank to a rocky bottom survived, meaning that if these lines hadn't failed the product could in fact be submerged to a significant depth for a period of time. Also worth noting is the fact that although mussels survived being submerged at depth for a prolonged period, there didn't appear to be much growth during this time period. Mussels that were retrieved from these lines were much the same size as before they first sank.

Floatation Issues:

Norlantic Processors Ltd. and Go Deep International are presently examining the floats that failed, and in particular the ones that appear to have ruptured, exploded outward. The floats that crushed can be easily explained. We need to determine why so many floats failed by rupturing and in turn causing the complete failure of the mussel lines. Next to biological and environmental factors that affect the well being of the mussels themselves, floatation is perhaps the next most critical component for the projects success. Norlantic has lost a significant investment with   the failure of the floatation and the accompanying loss of product. The whole issue of suitable floatation for deep water aquaculture now needs to be re-addressed. It is simply too risky and potentially costly for a private company to gamble on an investment  in deep water aquaculture without first having some assurance that the raw product and capital cost materials won't be lost due to factors that we don't yet understand. More work is needed to properly address the floatation issue.

Work Platform:

The work platform was an integral component of this project. Although we had complete line failure due to floatation issue. The work platform with its modifications and specialized equipment preformed as expected. The job of handling the immense anchors and long lines has been made possible with this newly modified and well equipped vessel. As well, the addition of foam floatation to the under deck, and bow thrusters has also made operating a vessel under such harsh environmental conditions much safer.