A decade of exploitation and management of the Namibian hake stocks

Published source details van der Westhuizen A. (2001) A decade of exploitation and management of the Namibian hake stocks. African Journal of Marine Science, 23, 307-315.
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This study is summarised as evidence for the following.

	Action	Category
	Introduce an overall catch limit (quota cap or total allowable catch) by fishery or fleet Action Link

Introduce an overall catch limit (quota cap or total allowable catch) by fishery or fleet

A before-and-after study in 1990–2000 of an extensive area of seabed and mid-water in the South Atlantic Ocean off the coast of Namibia (van der Westhuizen 2001) reported that after introduction of annual catch limits (total allowable catches) the biomass of hake Merluccius spp. increased. Data were not tested statistically. During the period after new total allowable catches were set (at 60,000 t), total hake biomass increased from 500,000 t in 1990 to 900,000 t in 1992. Biomass gradually declined in the years following, to 550,000 t in 1997, but increased again between 1998–2000 (1,000,000–1,300,000 t). During the same period, total allowable catches increased to 87,000 t in 1992 and to 160,690 t in 1999, and numbers of vessels participating in the fishery rose from 55 (1991) to 105 (2000). The authors noted that the decline in hake biomass between 1992–1997 was probably the result of anomalous environmental conditions in 1993–1995. New, conservative catch limits were imposed from 1990 following Namibian Independence. From 1992–1997, catch limits were set as 20% of the fishable biomass. However, conflicting estimates of abundance – research survey vs commercial indices – lead in 1997 to the introduction of new methodology to calculate abundance (see paper for details). Biomass data was estimated from 18 research surveys between 1990–1999. Bottom trawl transects were done 20 miles apart to assess bottom-dwelling hake. Mid-water hake were assessed using acoustics.

(Summarised by: Natasha Taylor)