Innovations to Produce Single Oyster Seed in Pendrell Sound, BC

Final Report
Aphrodite's Garden Oyster Company
AIMAP 2012-P14

Executive Summary:

This project utilized our unique methodologies for producing single oyster seed, in commercial quantities, locally, from the wild oyster spatfall in Pendrell Sound. We are responding to economic necessity and industry advantages.

This project demonstrated the possibility of excellent value in an economical, natural product: viable, large oyster seed for local growers, obtained through innovative mechanical developments designed specifically for this purpose. 

Our outcomes are increasing productivity of area farms, creating employment, protecting and enhancing a valuable asset on the BC Coast. These social, economic and environmental achievements will continue to be a great benefit to local growers and the area in which they work and to new possibilities within the aquaculture industry.

The process:

1.  Preparation of seed Collector substrate, remanufactured buckets;
2. Modification of existing equipment to Deploy and Retrieve collectors quickly, easily and, during retrieval, gently;
3. Construction of the Seed Stripper, to remove seed from collectors;
4. Construction of the Seed Sorter to separate single seed from clustered product.

Introduction

Project Manager: Ed Bereziak
Aphrodite's Garden Oyster Co
1840 Lund Hwy, Powell River BC
Project Dates: April 2012 to March 2013
Project Locations: Pendrell Sound; Okeover Inlet;

Severe shortages of oyster seed from American hatcheries highlight the fact that the BC shellfish aquaculture industry is overly dependent on foreign sources of seed. Included within this dependency are issues of trade security risk, regulatory issues, introduction of invasive species and poor quality seed with high mortalities. The situation has not changed since the beginning of this project and ocean acidification will continue to exacerbate the problem. 

Pendrell Sound has been known as a reliable seed source since 1948. Its proximity and productivity are very important components of this project. Okeover Inlet produces about 25% of the shellfish market on the BC coast due to its protected warm waters, which are exceptionally nutrient rich and pristine. 

Methodology:

The objective is to prove the viability of the production of high quality large oyster seed from the natural spatfall in Pendrell Sound, through particular spat collector medium, initial nursery rearing stages and automated mechanical processing and sorting in preparation for market.

Initially, food grade pails are remanufactured to function as Collector units. These are stapled onto strapping in 40' lengths and stored, sleeved together, on the Deployment Raft ready for quick immersion at peak larval production.

The Deployment and Retrieval raft consists of fish farm pens, modified extensively to function as a covered storage and processing area. This raft will also house the mechanical devices for processing collectors and seed.

Collectors are attached below ocean surface, using weights and buoys to adjust depth as required. They are monitored closely for spat set. Once set has been observed in sufficient quantities, the collectors and surrounding ocean are further monitored to determine ideal depth.

A collector Drydock, built of HDPE pipe, brings the seed-laden collectors out of the water to a stable work surface, the conveyor, on the raft using a hydraulic lift. 

The Seed Stripper rolls the collectors between two surfaces to compress the circular collector, disengaging the seed. Seed falls to the conveyor belt and continues on to be sorted.

Seed sorting is accomplished by a special mechanism fitted on the outfeed belt of the sorter called a Cluster Brush. For larger seed, we use a locally owned, professionally built sorting device, a Mulot Sorter.

Single oyster seed for longline tray and bag culture is the main deliverable in this project. The secondary deliverable is the Clustered seed, for beach stock and the shucking market. The mechanism design and engineered drawings are further main deliverables which we will obligingly share within the industry.

Work Plan as it evolved:

April, May, June
Equipment Assembly:  Initial project launch involved the purchase and assembly of materials and equipment; preparation and assembly of collectors. Collectors sleeved together for storage on Raft. 

July, August
Deployment / Retrieval rafts modified from existing structures, transported with collector modules to Pendrell for immediate placement. It was determined after modification was begun on the first raft that it had to be larger. This first raft instead became part of the grid raft system. A second, larger modification was undertaken to create an area about three times larger to form a covered work and storage area, also to house mechanical devices.

September - February
Collectors were systematically checked for fouling by organisms, mussels, starfish etc.; depth of collectors requires diligent adjustment to avoid fouling, depending on ocean conditions. 

February, March
Mechanical designs are updated as required to function appropriately. Drydock is being fabricated from HDPE pipe, using plastic welder. Stripper is well underway with the original design being followed closely. Sorter is nearing completion, again with few modifications. Field trials of these designs are going well.

Going Forward:

One of the threats from the Strengths, Weaknesses, Threats & Opportunities (SWOT) analysis in our original proposal was realized in that the 2012 seed set we managed to achieve was lower than we anticipated. This necessitated modifications to the work plan.

The project will ultimately show success in spite of the setback. More systematic monitoring will be included in future plans. Our follow up report to DFO will describe outcomes, modifications to equipment and its performance aspects.

The mechanical designs are only slightly altered from the original. The Deployment and Retrieval Raft modification (category 15) design in particular was enlarged to three times the original when it was determined to be insufficient to accomplish the work intended for it. It will now consist of a covered collector storage and processing area. It will also hold the Drydock, the Stripper and the Sorter.

Approximate Costs for Key Components:
Collector Float Structure: $8,000
Stripper: $9,000
Cluster Brush: $3,000
Solar Collection System: $7,500

Conclusion:

How the project impacted performance:

We discovered that monitoring spatfall levels required increased diligence; a presence in the area may be necessary for longer times during crucial periods. Aspects of the process may be more labour intensive than previously thought. Techniques around preparing collectors were altered in order to streamline the process. We moved from zap straps and ropes to heavy duty staples and strapping to hold the collectors.

Recommendations to others considering similar investments:

Experience in oyster production would definitely be a requirement. Cost effective and inventive means to develop processing units is necessary. The unique location of our spatfall collection area in relatively close proximity to our work base may represent a situation available to few growers. 

Sustainability Achievements:

We feel the project demonstrates the possibility of local seed production in sufficient quantities to enhance the aquaculture industry in all areas of sustainability - economic, social, and environmental. This example of innovative approaches to an established industry will encourage others to seek viable alternatives to increase production. This means more local jobs, increased cash flow, enhanced awareness by all involved of the necessity to protect the environment on which the entire process depends.

Progress Report:

During the 2013 seed set, the outcomes in Pendrell Sound were very impressive. Seed set on the collectors was much better than expected. Heavy rainfall, so we've lowered the collectors below the fresh water surface layer and to avoid the mussel set.