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New Observing Platform for Monitoring Fish Larval Trajectories


Summary:  The Caribbean Sea, Gulf of Mexico, and Straits of Florida contain spawning areas for a number of ecologically and economically important reef, mesopelagic, and pelagic fish species.  However, little is known regarding the transport and distribution of fish larvae throughout the area.  Understanding the degree of biological connectivity between remote marine areas by means of ocean currents, versus local recruitment of larvae, often aided by ocean eddies, will require targeted observations using the development of new observational techniques.  Observations from a platform able to monitor these trajectories and to assess larval transport are critical in biochemical models, to assess the link of the ocean and climate variability on ecosystems, and to improve current ecosystem numerical forecasts from seasonal to climate timescales. Existing observations for measuring larval trajectories currently rely on surface drifters, which are large buoys. The shape, size, and other characteristics of the standard drifter do not resemble those of fish larvae.   A new observational platform is needed to improve ecosystems assessments. Major issues to address will be: size of the platform, buoyancy changes to adapt for diurnal effects, measuring parameters such as temperature and salinity, determining their precise location, data recording and transmission, durability, cost-effectiveness, and expendability.


Project Goals:  Ocean variability, climate change, extreme weather events, and distress in ecosystems are linked to complex environmental patterns and with larval transport and distribution.  The goal is to design a new observational platform that can assess fish larvae trajectories and transports in order to properly associate them with changes in ocean dynamics, climate, and ecosystem parameters.  The main focal areas of this work are:  1) hardware and 2) capabilities.  Each of them presents a number of technical challenges.  Successful projects will produce a platform with a desired size (<10cm in diameter), biodegradable construction materials, in a cost-effectiveness fashion (up to $300 per unit); with capabilities that include changes in buoyancy (vertical motion of up to 10m), battery life (of the order of months to years), real-time transmission, data recording system, and capability to observe a minimum suite of environmental parameters, such as location, pressure and depth, temperature, salinity, light intensity, with an error of less than 5%.  The final platform will be a package that houses all sensors and suitable for ocean field deployments.


Phase I Activities and Expected Deliverables:

Activities for both focal areas:

·      Identify and carry out review of sensors and materials that can be used to manufacture the desired platform.

·      Develop and demonstrate capability to create a platform as described above that can be used to better approximate the trajectories of fish larvae by monitoring its trajectory, and capable of controlled vertical displacements..

·      Quantify errors associated with the data generated including location and environmental parameters.

Deliverables for both focal areas:

·      A detailed report documenting methods and results, errors and accuracy of sensors, with discussion of results and identification of success and remaining challenges, and cost analysis.

·      Provide a conceptual design of the desired platform for monitoring larval transport and presentation of a design review, diagrams, prototype schematics, drawings, and prototype hardware mock-up.


Phase II Activities and Expected Deliverables:

Activities for both focal areas:

  • Develop one or more prototypes of the platform to accomplish the desired capabilities developed during Phase I.
  • Provide renderings and footprints of the prototype.
  • Test prototypes in a controlled environment, where water circulation, light intensity, and environmental parameters are known in order to produce an assessment of the prototype performance and capabilities.
  • Evaluate observational errors from the prototype together with accuracy of sensors.

Deliverables for both focal areas:

  • Provide a detailed report of results of tests of the prototypes, including documentation of results, errors, accuracy of all measurements, identifying areas of success and of upcoming challenges, and cost analysis.
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