During the recent Seasteading Conference reports highlighted the benefits of different regions for proposed seasteads. Where some factors were favorable others were not - off the coast of East Africa is environmentally a very favorable location but the issue of piracy makes it forlorn.
Fish will definitely be a component, however there are a diverse selection of crops (even land crops) which can be farmed at sea. Africans are resourceful people I have complete faith they will overcome any storage issues once the need arises. I say almost all food production because I do acknowledge the need to support infrastructure, like refrigeration. You have a good eye for logistics though.
My main interest in seasteading sites is along the equator for sea farming, ocean thermal energy conversion (OTEC), desalinization, and precious metals extraction. Somalia would be a very good site for the reasons mentioned in the article. I favor design which leads to affordable mass migration to the seas by the many millions of people looking to improve their lives from the current conditions of poverty, tyranny, and horrific violence seen in many parts of the world.
There is a funding portal specializing in African startup companies, Humanipo, http://www.humanipo.com/ . The founder of Humanipo, Kresten Buch, contributed the prize money for the Seastead Institute’s Sink or Swim business plan contest.
One of the presenters at the Seastead Conference, Dr. Ricardo Radulovich from The University of Costa Rica, has done some some excellent work on low cost sea farming with support from the Bill and Melinda Gates Foundation. The web site for the research is http://www.maricultura.net/ .