Big Flip Floats for Commercial Oyster Aquaculture

Big Flip Floats for Commercial Oyster Aquaculture

Summary

The Great Eastern Shellfish Company farm raises premium quality salt oysters from spat to market size on Maryland’s Eastern Shore. We raise and harvest up to 250,000 quality salt oysters every 1-2 years, through modern float off-bottom aquaculture. Currently our oysters are raised in off-the-bottom floats consisting of flat mesh bags on rectangular PVC floats. It seemed to be the state of the art for off- bottom culturing of oysters for the half shell market. It does well, but there is a problem. The oyster floats we currently use produce excessive fouling, are wasteful, and are cumbersome to harvest. Fouling is labor and time intensive to remove, prohibits oyster growth, and reduces water quality. We have analyzed or tried every system out there. After having made many improvements to our floats over the years, we now envision a new float that combines the best features of the best containment systems in use. It’s called a “Big Flip Float”. It’s for commercial oyster farmers. It grows oysters off the bottom. It is easy to load, easy to keep clean and easy to harvest from. With a SARE grant, we intend to implement the new Big Flip Float (BFF) containment system, and compare the performance of the new system against current practices. The measured benefits of the BFF system, in comparison with the numerous systems currently in use, will be shared with other growers, looking for the best method for raising oysters. We hope the BFF system will be found among the best for commercial oyster production.

With the new BFF containment system, we intend reduce or eliminate fouling and reduce wasted resources. As a result, this improved system should enhance oyster growth, require less labor, produce less waste and environmental pollution, reduce costs, and improve water quality. With a SARE grant we are conducting a field trial of the new BFF system, in comparison with our current flat bag float system. This project will measure the performance of the Big Flip Floats with respect to the expectations listed above. Results will be measured in a test area (with big flip floats) and a control area (with flat floats), over the course of one growing season.

Objectives/Performance Targets

We are comparing the performance of the BFFs to our standard floats with respect to the following objectives:

1. Enhance oyster production, by allowing good water flow within the bags. Improving off bottom growing conditions may speed growth. If a higher percentage of oysters achieve market size on time, we can get more to market and have fewer to put back for another growing season.

2. Reduce labor, by reducing or eliminating biomass fouling, and hence the need for constant brushing and scraping of the bags and floats.

3. Reduce costs and waste by reducing the disposal of cable ties and damaged bags.

4. Improve our water quality, by slowing or ending the release of biomass into the water.

Time and expenses are being documented as they occur, in a log. Water quality data will be recorded biweekly for each system in the spring. At the end of the project, materials and labor will be totaled. Oyster size distribution at harvest will be measured. Water quality differences will be trended and averaged. All measures listed above will be compared for each system to look for significant differences in the outcomes.

Accomplishments/Milestones

To date, we have made the following progress:

1. Thirty-three rolls of mesh have been ordered and received along with an air compressor, air hose, staples, pneumatic staple gun, cable ties, and other supplies to build the BFF floats.

2. A total of 67 floats have been transformed into BFFs and launched. The BFFs were loaded with baby oysters from our up-weller and planted alongside the same number of oysters loaded into standard bags strapped to standard floats. This was done to compare growth progress in both types of floats.

3. As market sized oysters have been processed and sold from existing crops in standard bags, the oysters that were not big enough yet were loaded into BFFs and put back out to continue growing. We found the BFFs much easier to load and deploy than the bags to be strapped onto floats.

4. The BFF unloading rack has been constructed and will be erected in the water in the spring.

5. For outreach, we appeared in the Ocean City Waterman and Aquaculture Trade Expo showing of one of the first BFFs. It attracted moderate attention from watermen and folks who were interested in pursuing aquaculture for oysters. We also brought a BFF to last summer’s Harbor Day event in Ocean City, MD. A BFF demonstration video has been created for YouTube, comparing it to brushing a standard float. This video, a sample BFF, and flyers describing the benefits of the system will be at this year’s O.C. Waterman and Aquaculture Expo.

6. For performance comparison of the BFF to standard floats, we have been logging the time to prepare and load floats, time spent cleaning and repairing and handling bags and floats, time to harvest and process oysters for market, and costs for implementing each system. Preliminary data on dissolved oxygen differences in the BFFs versus standard bags has also been collected.

During this Spring and Summer, we will continue to monitor growth and water quality within the bags/floats for each system and provide an assessment of differences in outcomes for our final project report.

Impacts and Contributions/Outcomes

To date, we have observed the following outcomes:

1. Since the BFFs were loaded in the fall, there have been no apparent differences in growth between the two systems. Growth will continue to be monitored throughout the spring/summer.

2. Preliminary measurements show that levels of dissolved oxygen in the BFF are greater than in the bags strapped on standard floats.

3. Brushing fouling off bags on standard floats remains difficult and time consuming. Flipping a BFF over is quite easy and takes only about 6 seconds if using the BFF ‘flipping wand’.

4. The seaworthiness of the BFFs is better than the standard floats. In fact because of this observation we put BFFs inside deeper water farther out and they ride the waves well. The standard floats under the same rough conditions end up with torn bags or bags torn loose.

5. So far, the BFFs require less maintenance. Because the long lines that hold the BFFs in a row of five are attached to the long side of the float, they stay neatly in straight rows. In contrast, the standard floats often sway out of line causing float lines to get caught under the float and sometimes shear off the attached bags.

6. Based on these outcomes, we are currently evaluating how to finance the conversion of all of our standard floats to BFFs.

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