Title: Assessment of the Namibian hake (Merluccius capensis and Merluccius paradoxus) demersal longline fishery based on logbook data.

In Namibia, hake is one of the most valuable demersal fishing resources and an important source of employment in the fishing industry. The hake demersal longline fishery started in 1991, targeting mostly the cape hakes Merluccius capensis and Merluccius paradoxus. The Total Allowed Catch (TAC) of hake is approximately 160,000 tonnes, but only about 10,000 tonnes are caught by longliners. Currently, CPUE data from the hake longline fishery are not used for stock assessment purposes, despite the availability of logbook data. In this study, we conducted an exploratory analysis of the demersal longline logbook data and standardised the annual CPUE using Generalised Linear Models (GLMs) and Generalized Additive Models (GAMs). The results showed that the longline fishery operates mostly in the central area of the Namibian coast (between 22°S and 25°S). Since the fishery started to operate in 1991, there have been noticeable changes in the composition and operation of the fishery, characterised by higher effort in the early years (number of vessels and number of sets), followed by a reduction in 2006-2011 and stabilisation thereafter. Standardised CPUE values produced using GLMs and GAMs were very similar and relatively low between 1991-2008, followed by a large increase up to 2015, and a decrease thereafter. GLM is recommended as the method to be used because it has a lower AIC than GAMs. Except for the last three years, the general temporal trend in the standardised CPUE was similar between the longline and bottom trawl fisheries. The longline logbook dataset contains valuable information that can contribute to the management of the Cape hake stock in Namibia.