Miscellaneous numbers and symbols appear to float in the ocean as real and simulated waves rise in the background


At Kelson, we're always building and refining our library of tools and processes. We've had lots of cool opportunities to speak about and publish various methods. Now we'd like to share some practical tools with you.

Toby Dewhurst
Kelson Marine CEO

Exposure Index Calculator

Kelson Marine is an active member of the ICES Working Group for Open Ocean Aquaculture (WGOOA). As a Working Group, we have convened farmers, engineers, regulators, and scientists to resolve the present ambiguity in the term "Offshore Aquaculture". The Working Group now recommends two distinct metrics to quantitatively describe aquaculture sites:

"Distance from shore": Sites are described by their distance from the coast.

"Exposure": Sites are further described with an exposure index that incorporates the design wave, current velocity, and depth of the site.

This distinction addresses a need to define the terminology to reduce ambiguity for characterizing aquaculture sites to:

  1. Promote a common understanding and avoid misuse of different classifications;
  2. Enable regulators to identify the characteristics of a marine site;
  3. Allow farmers to assess or quantitively compare sites for development;
  4. Equip developers and producers to identify operational parameters for the equipment and vessels; and
  5. Provide insurers and investors with better means to assess risk and premiums.

To help farmers, developers, regulators, investors, and members of the public apply these definitions, Kelson provides a calculator for the proposed exposure index definitions.

Map of Specific Exposure Energy in the German Bight


Lojek, O. Goseberg, N., Moe Fore, H., Dewhurst, T., Bölker, T, Heasman, K, Buck, B, Fredriksson, DW, Rickerich, S, 2023. A quantified approach to assessing hydrodynamic exposure of mariculture sites. Journal of the World Aquaculture Society. In preparation.

Buck, B. H., Bjelland, H., Bockus, A., Chambers, M., Costa-Pierce, B. A., Dewhurst, T., Ferreira, J., Føre, H. M., Fredriksson, D., Goseberg, N., Holmyard, J., Isbert, W., Krause, G., Markus, T., Papandroulakis, N., Sclodnick, T., Silkes, B., Strand, Å., Troell, M., Wieczorek, D., van den Burg, S., Heasman, K. 2023. Resolving the term ‘offshore aquaculture’ by decoupling ‘exposed’ and ‘distance from shore’ for managers and policy makers. Journal of the World Aquaculture Society. In preparation.

Hydrodynamic Exposure Calculator
Exposure Velocity:
Exposure Velocity at Reference Depth of 5m:
Specific Exposure Energy:
Depth-integrated Energy Flux:
Structure-centered Depth-integrated Energy:
Structure-centered Drag to Buoyancy Ratio:

We'll be adding to this collection going forward.

Ideas? Let us know!

What Else We're Up To

Toby Dewhurst of Kelson Marine adjusts load cell to measure drag on seaweed farm at St. Gelais

University of New England Partners with Kelson Marine on ARPA-E MARINER Project

Kelson CEO Toby Dewhurst stands on stage in front of the presentation at Seagriculture EU 2023

Seagriculture EU: Resolving ‘Offshore’ Aquaculture: Distinct effects of distance and exposure on the cost of seaweed

Toby Dewhurst, Kelson's CEO, accepting the 2023 SCORE Award for Best Innovative Small Business

SCORE Maine names Kelson "Best Innovative Small Business" in 2023

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