Sturgeon: Canada’s Diversified Freshwater Aquaculture Industry

Target Marine Ltd.

Table of contents

• Executive Summary
• Introduction
• Methods
• Results of Project Activities
• Spawning of captive wild fish at the hatchery
• Design of system for maturing adult fish
• Commence installation of retrofit recirculation system
• Maturation of domestic female fish
• Inaugural harvest of caviar and quality testing
• Implement preliminary management techniques to minimize the impact of viral diseases
• Compare fish cultured with different feeds
• Commence development of reliable and repeatable minimally invasive techniques for staging sturgeon
• Commence development of reliable and repeatable minimally invasive techniques for sexing sturgeon
• Conclusion
• Update on Project Activities

Executive Summary

Achieving the goal of developing Canada’s white sturgeon aquaculture industry will result in white sturgeon caviar having one of the premier values of any agriculture product in Canada. Under the highest environmental performance and traceability, Canada will become a new competitor in the global farmed caviar trade while helping to take pressure off endangered wild stocks. The objective of this project was to continue to develop innovative technologies and management techniques which would work towards ensuring a reliable and consistent supply of fish for production, and result in a successful model for white sturgeon culture in Canada. Many of the goals to work towards those objectives have been accomplished.

Introduction

Target Marine’s innovation, to develop a successful white sturgeon aquaculture industry in Canada, has passed through various stages of research, development, and early commercialization over the past twelve years. There is potential for this species to help diversify the freshwater aquaculture industry in Canada. Two main boosters are essential to enable this development: 1) a reliable and consistent supply of fish for production, and 2) a successful model for white sturgeon culture. The objective of this project was to continue to develop innovative technologies and management techniques which would work towards those boosters. There were four main goals to work towards in order to accomplish these objectives:

1. Refine techniques to advance maturation
2. Transfer and develop technologies for non-invasive sexing and staging techniques
3. Develop finishing diets and environmental parameters to optimize flesh and caviar quality
4. Develop management techniques to minimize stress and the impacts of sturgeon viral diseases

Since 1998, Target Marine has invested twelve years and millions of dollars in the research, development, and early commercialization of this species, successfully rearing six generations of sturgeon, some to extremely large sizes. The oldest group of white sturgeon production fish was hatched in the summer of 2000. Feeding trials and environmental preference trials were carried out over several years. Technology was transferred from the University of California Davis and other facilities worldwide. Indoor and outdoor recirculation systems have been built to culture juvenile and adult fish. The products resulting from this long term project have enormous potential to be commercialized and successfully penetrate and become a significant contributor to the global market. The conclusion of this long term plan will not only prove culture systems for caviar production, but also open the door to the development of the Canadian white sturgeon aquaculture industry. White sturgeon caviar will have one of the premier values of any agriculture product in Canada. With the detailed attention to environmental performance and traceability, this project will help position Canada as one of the world leaders in sustainable caviar supply, while helping to take pressure off endangered wild stocks. This will improve the global competitiveness of Canada’s aquaculture industry and help to meet the DFO strategic outcomes of sustainable aquaculture and healthy and productive aquatic ecosystems.

Methods

Most of the infrastructure, facilities and equipment were already in place to carry out the project as were several generations of fish.

The project included the preparation for and attempted spawning of the first wild captive white sturgeon at a commercial facility. This animal was attained from the Vancouver Aquarium. Although a small number of wild captive female white sturgeon have been spawned at Vancouver Island University (VIU), captive female white sturgeon have not been spawned at any commercial facility in Canada. Of the sturgeon spawns at VIU, approximately half of them have been successful in producing viable offspring. 

In order to help advance the maturation of the adult sturgeon, outdoor recirculation systems were designed. The construction of these systems is planned to be carried out over three years. This year of the project entailed the design and initial construction of a retrofit system from reuse to recirculation as well as converting flow through tanks to reuse. The recirculation systems designed will conserve 99% of the water and 99% or more of the heating energy that would otherwise be required in a flow through system. When complete, these systems will allow the fish to be cultured in a natural photoperiod environment, while providing fine control of other environmental conditions.

To reach the goal of caviar production, the domestic female white sturgeon must mature. This project included the final stages of maturation of the first domestic female white sturgeon to mature in Canada. The first harvest of caviar can now take place. Expertise for this goal has been gained from UCDavis, other international sturgeon farmers and caviar retailers that have expressed a keen desire to be able to purchase the product once available. In order to optimize the performance of the fish and the quality of the product, the sturgeon were cultured on different feed types to determine the effects on the fish. The main objective of this work was to use feeds that work well in growing sturgeon and determine their effect on caviar quality. Performance of the fish was compared. The next step will be to compare the caviar quality.

Management techniques have been implemented to help minimize the impact of viral diseases such as WSIV and WSHV on the culture animals. This part of the project was carried out using the expertise of project partners Dr. Scott LaPatra and Joel Van Eenennaam. Some of the hatchery procedures and protocols that were changed include: updated biosecurity, new feeding regime, different temperature profiles, improved handling methods, and the timing of fish movements.

Results of Project Activities

Spawning of captive wild fish at the hatchery

Preparation for the spawning of the first wild captive white sturgeon at a commercial facility was carried out. This individual female was attained from the Vancouver Aquarium. Additional expertise from VIU and UCDavis were used for this phase of the project. Significant amount of resources went into ensuring the proper water quality and water temperature profile, as well as ovarian biopsies and monitoring of the progression of maturation. Although the fish ovulated approximately three weeks behind schedule, the resulting eggs were of reasonably good quality. Unfortunately all attempts to obtain sperm from one of more than twenty males were unsuccessful. The objective of spawning a wild captive female at the hatchery was completed, though the overall spawning event was not successful. The next attempt to spawn a wild captive female at this facility will likely occur in 2012. Production was not negatively impacted from this spawning event as eggs were previously purchased from VIU for production purposes.

Design of system for maturing adult fish

In order to assist in the maturation of the adult sturgeon, outdoor recirculation and reuse systems were designed for these fish. The recirculation systems designed will conserve more than 99% of the water and heating energy that would otherwise be required in a land based flow through system. The design of these systems is complete. The retrofit system was designed and dimensioned together with the engineering expertise from PRAqua and using expert consultation and expertise in white sturgeon culture and recirculation systems. The design of this system is repeatable on other existing reuse tanks and will result in systems that enable control of the rearing environment, conserves water, and conserves heating energy in an outdoor environment. 

Commence installation of retrofit recirculation system

This part of the project will be carried out over multiple years. With the design complete and the system components delivered to the site, installation of the first system is almost complete. After a more thorough electrical evaluation, it was determined that an additional back-up generator was required for the new pumps and was subsequently purchased and installed. Tanks being retrofit with recirculation technology were running with approximately 50% of the water flow being pumped through a CO2 stripping and oxygenation tower at the start of the project. Certain challenges had to be overcome as the tanks already housed sturgeon at the time of the retrofit. New installation techniques developed will be valuable in the future as it opens up the possibility of converting large numbers of tanks without having to remove the fish.

Maturation of domestic female fish

To reach the goal of caviar production, the domestic female white sturgeon must mature.  Specific work has been carried out since 2007 at which time it was discovered that the maturation rate was different than that of fish reared at UCDavis. Different feeds and environments have been used to help determine which natural factors can advance maturation. This goal of the project, to get domestic females to mature, has been accomplished on a small scale. After 11 years, a small percentage of the first production population of domestic female white sturgeon have matured and developed eggs to the stage of caviar production, and soon to the stage of spawning. The oldest population of fish was evaluated, one fish at a time, by biopsy to determine the stage of ovary development. Fish were reared in two separate systems resulting in different percentages of maturation from the populations. The new system being implemented combines benefits of both of the existing systems and will hopefully result in an advanced maturation rate. The first spawning of a domestic female white sturgeon is scheduled for the summer of 2011.

Inaugural harvest of caviar and quality testing

The first of the domestic females have matured and are being reared on a naturalized winter environment in order to optimize caviar quality. Much work has been carried out in setting up proper equipment and materials. A small number of fish are now ready for harvest. The inaugural harvest of caviar is scheduled for April 2011. Two of the Target Marine employees met with the University of California Davis partner at a caviar processing facility in California and participated in the collection of caviar quality data. Preparations have been made to collect these and other quality parameters once the harvest commences. Discussions have begun with another local university to become a future project partner. The completion of this step will represent a major milestone in the development of the white sturgeon aquaculture industry in Canada.

Implement preliminary management techniques to minimize the impact of viral diseases

This part of the project was to implement management techniques to minimize the impact of viral diseases such as WSIV and WSHV on culture animals. Literature and practical information on environmental parameters affecting the impact of white sturgeon viruses on production fish has been researched. Many of the variables affecting survival of sturgeon with a viral disease are unknown. Changes in management techniques have been implemented for the 2010 generation and older generations of sturgeon. Some of the hatchery procedures and protocols that were changed include: updated biosecurity, new feeding regime, different temperature profiles, improved handling methods, and the timing of fish movements. Biosecurity updates involved the restrictions in the incubation building. The feeding regime reduced stress to the animals and optimized food availability. Timing of temperature profiles were modified around potential exposure to pathogens. Fish handling has been changed to incorporate equipment that can move the animals to minimize physical handling and time spent out of water. To date, the 2010 group of fish has the highest survival of any sturgeon group cultured at this facility. The historic risk for a viral infection is over the next 10 months. These fish will continue to be cultured under these new management practices and observed on a daily basis.

Compare fish cultured with different feeds

Part of this project was to carry on with feed comparisons. The main objective of this work was to use feeds that work well in growing sturgeon and determine their effect on caviar quality. The first part of this has been completed. The caviar fish have been sorted out and the condition of the fish and percentage of fish ready for caviar has been compared between groups. All groups continue to be reared on the different feeds. The next phase of this will be to compare the quality parameters of the caviar between groups. This will be carried out in the next fiscal year.

Commence development of reliable and repeatable minimally invasive techniques for staging sturgeon

Progress has been made on this part of the project. Handling techniques were updated to enable the sorting of one tank of sturgeon per day. Some equipment was purchased and other equipment was designed and built to improve this process. The time per fish for sampling was significantly reduced compared to previous years and the handling of the fish was much less stressful both on the fish and the handlers. Improvements on the method to make it less invasive are yet to be developed.

Commence development of reliable and repeatable minimally invasive techniques for sexing sturgeon

Progress has been made on this part of the project. An ultrasound machine is being used in conjunction with internal visual examination to determine the sex of the fish. Much work is still required to develop this technique to a stage where it is 100% reliable on the size of fish required for sexing. Modified handling techniques have improved this process as well.

Conclusion

The project was completed on time and on budget. The project has met most of its goals and objectives. The objective of spawning a wild captive female at the hatchery was completed, though the overall spawning event was not successful. Nevertheless, much expertise was gained and the company is in a better position to successfully carry this out next season. Outdoor recirculation and reuse systems were designed for the sturgeon tanks. The design of this system is repeatable on other existing reuse tanks and will result in systems that enable control of the rearing environment, conserves water, and conserves heating energy in an outdoor environment. The new system being implemented combines benefits of both of the existing systems and will hopefully result in an advanced maturation rate. The retrofit on two existing outdoor reuse tanks commenced with the culture fish already in the tank. The techniques learned here will be valuable in the future as it opens up the possibility of converting large numbers of tanks without having to remove the fish. Changes in management techniques have been implemented for the 2010 generation and older generations of sturgeon. Some of the hatchery procedures and protocols that were changed include: updated biosecurity, new feeding regime, different temperature profiles, improved handling methods, and the timing of fish movements. These changes have resulted in a reduction of stress and an improvement in the efficiency of sexing and staging the fish. Diets and environments have been compared in terms of fish performance and will soon be compared for their effect on caviar quality. After 11 years, a small percentage of the first production population of domestic female white sturgeon have matured and developed eggs to the stage of caviar production, and soon to the stage of spawning. The completion of this step will represent a major milestone in the development of the white sturgeon aquaculture industry in Canada.

AIMAP funding has helped to enable this project which will assist in facilitating the production of white sturgeon caviar, thus contributing to the sought-after diversification of the Canadian freshwater aquaculture industry. Canada is now one step closer to becoming a new competitor in the global farmed caviar trade while easing the pressure on endangered wild stocks.

Addendum

Update on Project Activities

At 11 years of age, a small number of domestic female white sturgeon matured. These fish were identified by biopsy in the fall of 2010. Eggs were approximately 3 mm in diameter and fully pigmented.

Canada’s inaugural harvest of white sturgeon caviar took place in the spring of 2011. 89 fish were harvested for caviar. The quality was spectacular and the product has received accolades from consumers across North America and Asia. The product brand is “Northern Divine”.

Some of the mature fish were not harvested, but were kept as broodstock. Canada’s first domestic white sturgeon spawning was successfully carried out in the summer of 2011. The resulting offspring represent the first F2 generation domestic white sturgeon in Canada.