have you considered asking local fisherman what it is they can catch and eat in the winter, even a little north of you? i know it might prove hard to provide the temps that a deep (ish) channel would provide but it might be easier than picking a species out of a hat.
i know it might prove to be a bit of a financial burden, but what about building a greenhouse with a low ceiling? the lower the ceiling the less you have to heat.
i am familiar with the idea of aquaponics. please forgive me though if my ideas are a bit out of reach... i am not too familiar with too many species. i would think though that not too many veggies would winter over too well if the fish are too cold also. that will pretty much blow your whole idea i would think because there would be nothing to eat up your nitrates which would climb very high in an aquaponics setup when plants are not plentiful to eat them up. plus this would leave you with whole seasons where you cannot reap the benefits of sustainability. in other words you'd have to watch what you eat from your system in the colder months for fear of having to start all over and re-invest the next year to a point.
i know it might prove to be a bit of a financial burden, but what about building a greenhouse with a low ceiling? the lower the ceiling the less you have to heat.
i am familiar with the idea of aquaponics. please forgive me though if my ideas are a bit out of reach... i am not too familiar with too many species. i would think though that not too many veggies would winter over too well if the fish are too cold also. that will pretty much blow your whole idea i would think because there would be nothing to eat up your nitrates which would climb very high in an aquaponics setup when plants are not plentiful to eat them up. plus this would leave you with whole seasons where you cannot reap the benefits of sustainability. in other words you'd have to watch what you eat from your system in the colder months for fear of having to start all over and re-invest the next year to a point.