How do you decrease biofouling in shellfish?

Some very clever scientists have come up with very practical, non-chemical means of decreasing shell deformities and biofouling in bivalve culture. Check out the article below.

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Aquaculture Volume 325, Number 9 (January 2012) Using stocking density modifications and novel growth medium to control shell deformities and biofouling in suspended culture of bivalves Authors: A. Dunham, R.D. Marshall Author Affiliations:

Source: Aquaculture, Volume 325, Number 9 (January 2012) Page Numbers: 234 – 241 Available Full Text:

Abstract: Bivalve aquaculture currently utilizes two main farming practices: intertidal (beach) and deep-water (suspended) culture. Although suspended culture offers a number of advantages during both nursery and grow-out phases, two commonly encountered issues – shell deformities and biofouling – lead to reduced seed and final product quality in some species and preclude other species from being cultured in suspension. None of the existing strategies for controlling these issues is efficient and fully reliable. In this study we tested the efficiency of two new methods for controlling biofouling and shell deformities in suspended culture of bivalves using basket cockle Clinocardium nuttalliias a model species. The first method involved a short-term increase in bivalve stocking density during peak plankton concentrations and biofouling settlement periods. The second method comprised adding artificial growth medium (expanded clay aggregate) to culture enclosures. Both high-density and growth medium treatments significantly reduced the incidence of C. nuttalliishell deformities compared to the control treatment (by 86 and 72%, respectively). This finding suggests that clam shell deformities in suspended culture primarily develop due to the lack of structural support normally offered by the substratum. Both treatments also significantly reduced barnacle fouling rate (by 67 and 83%, respectively). Additionally, growth medium treatment led to a significant reduction in tube worm fouling, as well as combined fouling rate and intensity, but it was less effective in controlling sponge fouling. Overall, both high-density and growth medium treatments showed promise in reducing the incidence of shell deformities and the amount of biofouling on C. nuttalliiin suspended culture. These treatments are inexpensive, environmentally-friendly, readily available to shellfish growers, and may be further refined and adapted for a variety of cultured bivalve species. They have the potential to improve the efficiency of suspended grow-out systems and extend the option of suspended culture to bivalve species currently grown on the beach only. Citation: A. Dunham, R.D. Marshall . Using stocking density modifications and novel growth medium to control shell deformities and biofouling in suspended culture of bivalves. Aquaculture, Volume 325, Number 9 (January 2012), pp. 234-241, URL: http://ejournals.ebsco.com/direct.asp?ArticleID=49548B86958E34D17565