I was camping and caught a fish that was a bit too big for the cool box (I'm ever the modest fisherman). The weather was cool and dry so I dried some using concentrated sea water as I didn't have enough salt for the job.
Fish low in oil are better for drying - for example the famous Spanish dried salt cod, baccalao. Oily fish will end up quite smelly, although some asian dishes do call for this particular "ripe" flavour.
Step 1: Make Brine by Boiling Sea Water
Boil sea water until its really salty. How salty? I'd stop just as crystals start to form so its basically saturated. Professional salt makers when drying sea water keep the crystals that initially form but don't completely dry it, rather stopping and discarding the last little bit of liquid because it contains bitter salts like calcium chloride. In this recipe I just went for the "full taste of the ocean" salt profile. I ended with enough concentrated brine to just cover the fish fillets.
Step 2: Skin and Cut Fish Into Strips
I used the tail section for drying because it is less oily and better for cuffing into long strips.
Skin the fillets by sliding the knife under.
Step 3: Soak Fish in Brine Then Hang to Dry
I soaked the strips for about 15 minutes. Longer will help draw more moisture out of the fish but it will get much saltier. I hung them on a sharp stick that was flame "sterilized" by running through the stove burner. If it ended up too salty it will preserve even better but you would have to soak it in fresh water first before eating, like salt cod.
Step 4: Defend Your Protein!
Flies were a big problem so I made a tent with cloth. This dark colored sarong has a loose weave that allowed good airflow and also captured a lot of heat from the sun. I had to whack the marauding campsite goannas with a stick to keep them away. Within a couple of hours the fish formed a hard plastic-like skin. Once it's safely sealed like this it can be move to wherever conditions look favourable for further drying. Try the roof racks of your car?
How did it turn out? a couple of days later its almost dried right through. It's pretty salty and a tasty chew with a cold beer. You'd have to be a fan of really strong fish flavor. The very mild bitterness from not using pure sodium chloride was not unpleasant. It's also is a good addition finely shredded to Thai style dishes that call for fish sauce - which is all about super salty fish flavour!