O’Neill notes that “fishing was a significant industry along [...] the shores of the Black and Azov seas: each year four million fish – fresh and salted – sold for something on the order of 40,000 silver rubles in markets near and far.” Despite this, there is no indication on this map that fish stocks were an abundant resource or the basis of a profitable enterprise. Unlike some land-based resources and industries, like the salt lakes, freshwater springs, vineyards, or orchards, this information does not find visualization in this map and could thus be considered a blank spot. (O'Neill, 254)