Wednesday, July 3, 2013

Aquaculture in a Brighter Light

Last week I was able to accompany aquaculture specialist, Michael Chambers, in New Castle to assist in his research involving steelhead trout.  Chambers and UNH professor Dr. Hunt Howell have teamed up to study stock enhancement of steelhead trout by farming them in offshore pens that provide a safe environment for the trout and a convenient location for fishermen and researchers.

Chambers informed me that farming fish tends to come with a negative impression, as having all these fish together in the offshore pens increases the nutrients in the water harming the environment.  To offset this problem, Chambers has utilized the naturally growing mussels and kelp in the water to absorb these excess nutrients.  Since mussels are filter feeders, they take water into their system and filter through the detritus and plankton.  The nutrients produced by the fish are exactly what the mussels need to grow, therefore having the mussels around the pens maintains the water quality for the fish while allowing the mussels to grow naturally. There are many benefits to using these mussels. Such as, being able to sell them when they reach market size and the nutrient uptake discussed previously.

 We started our day by taking mussels Michael was growing off-site from the pens and putting them in long tubes of netting to assist and protect them in their growth.  We used the system shown below to make this process as simple and efficient as possible. These long nets of mussel can then be attached to the outside of the trout pens where they will continue to grow and consume the excess nutrients around the cages.  The netting will keep the mussels contained so they are not preyed upon at the cages.
Above: Mussels are pushed from the funnel, through the tube, into the netting.

Seeing the offshore trout cages was amazing and the trout seem to be growing well.  This growth combined with the use of kelp and mussels to maintain if not improve the surrounding water quality definitely helped me to see well-practiced aquaculture in a positive way.
          Above: Off-shore steelhead trout pens.  New Castle, NH.  

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