Aaron Bennett

MSc Candidate

Aaron Bennett

BSc, Memorial University
Contact: a.bennett@unb.ca

Research: "New techniques for measuring mollusc responses in field research"

In 2001 a collaborative project began to investigate the viability of integrated multi-trophic aquaculture (IMTA) by co-cultivating salmon (Salmo salar), kelp (Laminaria saccharina) and blue mussels (Mytilus edulis) in the Bay of Fundy.  The project will help to quantify the economic and environmental benefits and serve as a model for developing integrated, sustainable aquaculture. 

The overall project has numerous objectives including several to study (1) the characteristics of suspended particulate matter associated with salmon farms, (2) evaluating blue mussels as bio-filters to remove excess particulate material, and (3) respiration rates for mussels and kelp held at the farm and potential impacts of the additional biomass on dissolved oxygen concentrations. 

A combination of standard water sampling techniques and new high definition in-situ videography were used to assess the release of small particles, less than 10μm, and larger macroflocs > 500μm, both types potentially representing food particles for the mussels.  Feeding responses in the field were evaluated by assessing exhalent siphon areas of mussels recorded using time lapse video and a pair of digital video cameras in underwater housings.  Respiration rates for blue mussels and kelp were recorded in daylight and at night in clear acrylic chambers submerged at the site using temperature compensated DO probes and a data-logging DO meter.

Salmon aquaculture sites provide a nutrient enhanced environment and blue mussels responded by increasing their feeding activity and subsequently growing faster at salmon sites than their counterparts held at adjacent reference sites. The potential contribution of any additional mussels or kelp held at salmon sites, using the IMTA approach, to the dissolved oxygen budget needs to be considered by industry and regulators when making informed decisions about managing aquaculture sites.

Research: "How efficient is the blue mussel (Mytilus edulis L.) at filtering excess particulate material at an integrated (salmon-mussel-seaweed) aquaculture site?"

In 2001 a collaborative project began to investigate the viability of integrated aquaculture (finfish/shellfish/seaweed) in the Bay of Fundy.  The project will help to quantify the economic and environmental benefits and serve as a model for developing integrated, sustainable aquaculture.  The present study has two main objectives:

1) characterizing the suspended particle field within and surrounding a integrated aquaculture site using various methods to capture the entire size range of suspended particulates and

2) determining the uptake and absorption of suspended particles on the integrated aquaculture site by the blue mussel, Mytilus edulis. 

We are using videography to capture the size distribution of undisturbed particles from a minimum of 100µm to the upper range of particle size limit.  Particles smaller than the range of the video resolution are measured using a Coulter Multisizer which results in a size distribution pattern for individual particles measured. 

In order to obtain a more complete picture, a biodeposition rate is calculated from the feces and pseudofeces deposited by the mussels during the feeding trials. A net rate is then calculated for the amount of particulates completely removed from the system. We believe this research will support the assumption that mussels play a vital role in the environmental sustainability of integrated aquaculture in the Bay of Fundy.