A method of fishing using installations of the fish‐park type, known collectively as acadjas, is common in the coastal lagoons of Dahomey. Acadjas are installed in shallow sheltered waters and are constructed of dense masses of branches planted in the muddy bottom. Two main types exist, small circular acadjavis and large rectangular avas, but these may be combined to give a variety of other forms. After construction the acadjas are left for varying periods before being fished. Many species of fish are found in the installations, but the majority of these are only casual invaders and most of the catch consists of 3 species only. The fish population appears initially to be derived from immigration, but after c. 2 months of implantation, increases exponentially by growth and reproduction. Acadjas that are fished after short periods of installation are therefore regarded as refuge traps, drawing fish from the surrounding environment, where those that are left longer before being fished, develop their own populations. The yield of the acadjas also increases logarithmically with increasing densities of branches planted. Properly managed acadjas may be regarded as a method of fish culture, which, because of the exceptional yields that can be attained, are a potential means of development for shallow mud bottomed waters such as the West African coastal lagoon