Remove the guts, gills, blood line and any other nasty bits. chop the salmon in to 6-8" pieces, and chop the head in half length wise.
Toss the Salmon pieces with salt and set aside.
Chop the Leeks, Carrots & Onions finer than a quarter inch. Heat butter and oil on low until melted and incorporated with the oil. Sweat the vegetables for 10 minutes with the lid on, stirring occasionally to prevent sticking.
Remove the salmon parts from the bowl and add to sweated vegetables. Replace lid and let sweat for 5 more minutes.
Add the gallon of water, bay leaves, tomatoes and peppers corns. Bring to a shallow simmer for 1 hour.
Remove heat and let stand for 30 minutes
Strain through fine mesh strainer and save.