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Evolutionary ecology

Yusra finished her Master thesis

Female bearded gobies mature in anoxic waters off Namibia, finds Yusra Taha

Yusra Taha on field work where she sampled gobies in the lab of National...
Yusra Taha on field work where she sampled gobies in the lab of National Marine Information and Research Centre (NatMIRC) in Swakopmund Namibia February 2012.
Photo:
Anna Gro Vea Salvanes

Yusra Farouk Taha has been studying Variation in maturation and fecundity in African bearded goby Sufflogobius bibarbatus for her MSc Thesis, University of Bergen. The happy ending of this work occurred on September 20th when Yusra successfully completed her master exam in Marine Biology. She has studied fish samples collected in April of 2008 from a cross-shelf transect off the shore of Central Namibia and materials collected in January/February of 2012 from along the Namibian continental shelf from 17°S southward to 27°S.

Yusra developed first a macro-scale of sexual maturity stages of females, and next got it set and confirmed by histological analysis of gonads. The relative fecundity, including recruiting oocytes, was 1584 ± 1355 g-1. This was calculated using advanced oocyte packing density theory and stereological measurements assisted by an image analysis program.

The results show that the females can mature at low oxygen concentrations (DO=0.2ml/l) which is in anoxic waters! In the Central subarea, both DO concentrations (from 0.1ml/l to 1.0ml/l) and the chance of finding mature females increase outwards the shelf (figure on the right). These data suggest that the outer shelf area of central Namibia is a site where bearded gobies reproduce.