Dumba-fishing was invented at Lake Chad about 10 years ago by immigrant fishermen from Mali and Nigerian Hausaland. The new technique brought about a new era of Lake Chad fishery, characterised by social and institutional changes. Titled Kanuri fishery headmen (Kacalla njibe)2 who traditionally controlled the access to the lake's water were unable to cope with the massive influx of immigrant fishermen. The lack of an institution for effective control lead to serious conflicts between local and immigrant fishermen. With the Fishermen Association Marte Local Government a new institution was invented, in which local and immigrant fishermen, regardless of their ethnicity, should control access to the fishing grounds together. The Fishermen Association was modelled after “modern” urban institutions and thus mirrors the transformation of the lake shores from rural backwaters, with local customs and culture to an economic centre, characterised by inmigration, cultural diversity and several other 'urban' traits.