Surveys of fishermen and fishing activities during 1975,1976 and 1980 show that more than 700 people were part-time fishermen. Large mesh gill nets were used to catch predorn~nantly large cichlid species and catfish. The rota1 annual gill ner catch in 1980 was estimated at more than 700 000 kg but may be considmbly higher. Experimental gill net catches yielded higher catches in the small mesh ners, indicating a resource that was underutilized by the commercial fishery.
Water content and CO2 exchange of the fruticose lichen TeIoschistes capensis were followed for a measuring period of eight days in the coastal fog zone of the Namib Desert north of Swakopmund, Namibia. Fog, dew, or high vapor pressure of the air alone can provide atmospheric water sources for photosynthetic activity. Through a combination of dew condensation and fog, hydration of the thaIli during the night resulted in predawn dry weight-related water contents of the thalIi greater than 100%.
The wild dog Lycaon pictus has undergone an extensive reduction in range and numbers in the southern African subregion in recent years. Little information is available on its distribution and status in Namibia. Results from a questionnaire survey show that wild dogs have become highly restricted in their distribution and that numbers are decreasing. This species is now the most endangered large mammal in Namibia and nowhere is it adequately protected in this country. Wild dogs cause minimal domestic stock Iosses but are aggressively hunted wherever they occur in livestock farming areas.
The effects of the insecticide used for the control of GIossina morsitans (tsetse fly) on the weevil Cyrtobagous salviniae Calder & Sands were investigated. The latter is currently used as a biological control agent against the aquatic weed Salvinia rnolesta Mitchell. The survival of C. salviniae was measured after the application of an insecticide mixture of endosulfan and alphamethrin at different dosages.
The behaviour of captive solitary animaIs of the species Gerbillurus poeba paeba, G.p. exilis, G. tytonis, G. setzeri and G. vallinus is descriptionbed. Few interspecific differences were found in locomotion, feeding, grooming, sandbathing, nestbuiIding and exploratory behaviour. The main form of Iocomotion in all species was quadrupedal saltation. G, tytonis had a significantly longer leap length that G. paeba in the field.