NOSy - magnetic and wireless sensor technology for improving profit, biosecurity and carbon footprint of regional oyster production

Scientific background
In the life-cycle of many commercially-grown bivalves including oysters, the settlement of free-swimming larvae onto suitable substrate is a key step in extensive aquaculture that provides the foundation for crop growth. In oyster aquaculture, this is either (i) managed through traditional knowledge of oyster farmers, (ii) unmanaged but bypassed with the import of oyster juveniles from other areas or hatcheries or (iii) poorly considered in artisanal fisheries by oyster small-holders.

Research methodology
We have developed a sensor prototype that quantifies the gaping activity in bivalves and have demonstrated that this sensor can detect differences in gaping behaviour between normal feeding and spawning behaviour.
This project aims to develop this prototype into functional units for deployment in oyster aquaculture. Specifically we have teamed up with our original investor, Colchester Oyster Fishery based on Mersea Island in Essex, to develop this sensor into a product use to inform them of high probability of spawning activity to facilitate their management and culture of oysters - ideally to increase their yield of free swimming oyster larvae onto spat collectors or oyster "cultch" - crush shell they can place on an inter tidal oyster cultivation area for oysters to settle onto.

Our project will complete our development of a single sensor into an array of sensors that can work with multiple oysters at the same time. Then we will build in both environmental data sensing technology and a method for the array that may sit out on an estuary to send data back to "base" using 4G communication links and so that the oyster producer can check on their oysters. As should be evident this means the sensor has many other potential uses such as understanding whether oysters are feeding when expected or experiencing stress - neither of these observations are currently possible with looking at long term growth of oysters. By the time declines in growth occur it may be the case that it is too late to act upon it.

Impact

This is an impact orientated innovation project with a very clear set of deadlines and a single clear obtainable impact deliverable - to increase spatfall and juvenile oyster yield so as to increase profitability and product quality and supply for Colchester Oyster Fishery. The technology we are developing may be of itself of commercial value and has many other potential uses with other shellfish and sedentary livestock production.

We will apply existing knowledge on high-frequency, non-invasive (HFNI) sensors for the remote monitoring of oyster spawning. We recently developed a sensor that monitors gaping width (amplitude) and frequency based on a light-weight Hall Effect magnetic sensor fixed to one valve of the oyster shell that senses the distance of a small neodymium magnet (0.5g) fixed to the other valve of the shell. The sensor and magnets were placed onto the two oyster valves using non-toxic epoxy putty. After calibrating the closed state, fields between 1 and 500 gauss were detected by a microcontroller and were proportional to the open or closed state of the valves. The data logger (Arduino Uno) can record readings from 500 us to tens of minutes, logging the time, date and distance measure of the valve opening. Together, this system was capable of quantifying the gaping width and gaping frequency of individual oysters. The gaping activity of M. gigas during feeding is irregular and infrequent but this increases significantly during spawning. For example, measurements with M. gigas indicate that the spawning signal comprised the rapid and regular movements of the valves with strong contractions of the adductor muscle. The entire spawning event lasts from few minutes to about an hour and can include bursts in excess of 50 contractions with periods of several seconds between each contraction. From a single sensor we plan to multiplex up to 10 sensors into an aggregation unit that can house further data storage (backup) and data inputs from environmental sensors - a sensor array. From this array we will switch the signal to a two-wire rugged cable that will transfer the data to the surface where a 4G transmitter will allow data to be sent to base for evaluation of likely spawning behaviour. Constant and sequential use of spat collectors near oyster beds will allow us to compare our predictions to field observations.

This proposal is entirely Impact driven and aligned to the needs of a specific end-user, our project partner Colchester Oyster Fisheries (COF).

To realise this impact we have spent considerable time building a relationship with COF, including them in the project from its very initial ideas to its current single sensor prototype.
It is clear that COF have a real interest in the technology and a wish to use it to their benefit within their business. Therefore the most important steps to realise our impact have already been undertaken - we clearly identified the stakeholders need and developed a plan to deliver on that need.

We have a single impact objective - to develop our new technology and use it to achieve a significant increase in juvenile oyster collection for COF.
We can measure the success of this clear and obtainable impact objective by comparing the self-reared 0-1+ age oyster biomass by COF on average over the last ten years, and comparing that to the biomass we can obtain for them in each of our study years as 0+ juveniles and subsequent yield in the following years.

We have set out a clear timescale of project deliverables, stakeholder meetings and communication strategy in our case for support. This provides a clear project managements structure, from PI/CoIs working with the PGRA and COF to make sure communication, feedback, critique and information is able to flow freely between COF and the two University institutes.