River Fisheries Through the Ages

The aim of this chapter is to give a concise review of river fisheries through the ages in the Delta. The past and present status of a number of anadromous fish species in the Delta water will be discussed: sturgeon, eel, allis shad, twaite shad, smelt, some coregonids, sea trout and salmon. Nowadays, most of these species are rare or endangered, and some became virtually extinct. Of the ‘big three’, sturgeon, allis shad and salmon, the salmon came on the first place, all year through a regular customer in the rivers, except during a short period in winter. In the 19th century, or perhaps far more earlier, a major decline in catches set in, for some species earlier than for others. A complex of causes thought to be responsible for the dramatic decrease of fish stocks in the Large Rivers will be dealt with in this chapter. Most of these causes are related to the river regulation and normalisation works, as discussed in previous chapters. Habitat loss ranks among the most important factors, and severe water pollution might be considered as the death-blow to some species.