Evaluation of the Status of the Namibian Hake Resource (Merluccius spp.) Using Statistical Catch-at-Age Analysis.Namibian hake is the most important fish resource in Namibia. This monograph is a compilation of all the hake data, historic and recent, that has been used to inform stock assessment and management since the late 1970s. It presents the statistical catch-at-age analysis used to evaluate the state of the Namibian hake resource under different assumptions. This analysis treats the two hakes, Merluccius paradoxus and M. capensis, as a single stock. The data and modeling show that the stock has not as yet recovered to its maximum sustainable yield level, despite foreign fishing effort having been removed in 1990. Best estimates suggest the current stock to be roughly 20% of pre-exploitation levels; however this figure is sensitive to model assumptions. Signs indicate that the stock is slowly recovering from its all-time low in 2002-2004. Because the two hake species are pooled for assessment, the resource is currently managed on a relatively simple adaptive basis; 80% of the estimated replacement yield is reserved for fishing, the remainder being left for rebuilding.
Short-term variability in alongshore winds and temperature off Swakopmund, Namibia, during a non-upwelling event in 1998-1999.Swakopmund is a popular coastal resort in Namibia, especially during the summer holiday season when daily sea temperatures can fluctuate several degrees in a short period. Hourly measurements of the nearbottom water temperature were collected off the Swakopmund Jetty to investigate the thermal variability in relation to local winds. The thermal regime of this coastal region appears to be controlled by the locally forced Ekman offshore transport. Related changes in offshore transport led those of the surf-zone temperature by about one day. A transfer of kinetic energy from the alongshore wind into the temperature field of the nearshore zone dominated relative short time scales (hourly). The longer periods (7–9 days) are associated with the forcing of poleward-directed continental shelf waves. The origin of the 24–25 day frequencies is not clearly understood. However, it characterises the nearshore wind field as well as the water temperature of the surf zone. These relatively long quasi-cycles could originate from rhythmic changes in the regional wind field as a result of changes in the thermal contrast between sea and land areas.
Ministry of Fisheries and Marine Resources Namibia, Annual report 2004The Ministry of Fisheries and Marine Resources is responsible for the management and development of fisheries and aquaculture in Namibia