You can manage bookmarks using lists, please log in to your user account for this.
Media type:
E-Article
Title:
Spatial and biomass structure of shallow‐water cape hake (Merluccius capensis) in the light of episodic environmental shifts
Contributor:
Bahamon, Nixon;
Kathena, Johannes N.;
van der Plas, Anja K.;
Kainge, Paulus;
Paramo, Jorge;
Gordoa, Ana
imprint:
Wiley, 2022
Published in:
Fisheries Oceanography, 31 (2022) 5, Seite 524-538
Language:
English
DOI:
10.1111/fog.12602
ISSN:
1054-6006;
1365-2419
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title><jats:p>The spatial distribution patterns of <jats:styled-content style="fixed-case"><jats:italic>Merluccius capensis</jats:italic></jats:styled-content> in the Namibian waters were investigated and related to average environmental conditions during 1996–2020. Fisheries‐independent data and simultaneously collected water temperature and dissolved oxygen data were used from austral summer surveys. A geostatistical kriging approach was employed to evaluate the spatial structure of hakes. Links to environmental conditions were explored via data‐driven generalized additive models (GAMs). <jats:styled-content style="fixed-case"><jats:italic>M. capensis</jats:italic></jats:styled-content> generally exhibited average patch sizes between 40 and 50 nm at depths between 180 and 280 m. During the extreme episodic water warming in 2011 related to a Benguela‐Niño, the hake patches shrank up to a historical minimum of about 13 nm and moved offshore showing maximum densities at unusual deeper bottoms between 260 and 320 m. The deepening and size reduction of aggregations did not alter the biomass estimates (570 kt) that remained within historical ranges (249–811 kt). Although other extremely warm and cold summers were reported during the study period, no significant impact on the <jats:styled-content style="fixed-case"><jats:italic>M. capensis</jats:italic></jats:styled-content> patch size was detected. Maximum <jats:styled-content style="fixed-case"><jats:italic>M. capensis</jats:italic></jats:styled-content> densities were linked to optimal bottom temperature range between 10.1 and 11.8°C, dissolved oxygen values close to zero nearshore, and between 0.8 and 1.4 ml/L offshore. Potential changes of biomass produced by extreme environmental events remained undetected within the interannual biomass ranges, suggesting a high resilience capacity to episodic extreme environmental events.</jats:p>