Fig 1.
The green line in the top left inserted Fig shows the model domain. The nine release areas used in the simulations are indicated by the colours. Red, green, and blue are the main actual spawning zones for the two shrimp species on the Sofala Bank, whereas grey and yellow are non-spawning zones. Dark and light colours respectively indicate the inshore (in) and offshore (off) parts of the zones. Dark and light grey lines respectively indicate the 50 and 200 m isobaths. Base layers used to create this map are Diva-GIS country outlines, administrative divisions and rivers in the public domain (https://www.diva-gis.org/gdata).
Fig 2.
(A) Simulated larval density (numbers km-2, logarithmic scale) at the end of the simulations from all release areas and release times (every 3 days for five model years) during the five years experiment, and (B–F) examples of trajectories followed by simulated larvae over 15 days when released (black marks) from the northern (red), central (green) and southern (blue) release areas. For green and blue, dark/light colours respectively indicate inshore/offshore release areas. Base layer used to create this map is Diva-GIS country outlines in the public domain (https://www.diva-gis.org/gdata).
Fig 3.
Time series and boxplot of mean percentage of larvae lost during the five years of simulation when larvae were released from (red) all nine release areas and (blue) the five release areas (1, 3, 5, 7 and 9 in Fig 1) corresponding to the major spawning zones for shrimp on the Sofala Bank.
Grey shading represents ± s.e. for the five release areas. The horizontal dashed line indicates the 10% threshold. Letters on the X axis refer to January, April, July and, October for model years 4, 5, 6, 7, &8.
Fig 4.
Mean± s.e loss rates (%) from the nine release areas on the Sofala Bank: 1 –northern, 2 –north-central inshore, 3 –central inshore, 4 –south-central inshore, 5 –southern inshore, 6 –north-central offshore, 7 –central offshore, 8 –south-central offshore, 9 –southern offshore, as depicted in Fig 1.
Letters (a to d) on the top of the bars represent groups with similar loss rates identified from the Tukey post-hoc tests.
Fig 5.
Snapshots of simulated shrimp larval distributions (black dots) 5, 10 and 15 days after their release, superimposed on the corresponding ROMS−derived surface current velocity (arrows, in cm s−1) and sea surface height (SSH in cm, colours).
The purple line indicates the 50 m isobath. Base layer used to create this map is Diva-GIS country outlines in the public domain (https://www.diva-gis.org/gdata).
Fig 6.
2x2 self-organizing maps (SOMs) for sea surface height anomalies (SSHA in cm) derived from ROMS years 4−8.
In the top left corner of each panel the numbers 1−4 indicate the SOM pattern and its frequency of occurrence is reported in %. Blue colours (negative SSHA) indicate cyclonic eddies whereas red colours (positive SSHA) are for anticyclonic eddies. The purple lines indicate the 200 and 2000 m isobaths. Base layer used to create this map is Diva-GIS country outlines in the public domain (https://www.diva-gis.org/gdata).
Fig 7.
Cross-correlations between time series of simulated larval loss (Fig 3) and Euclidian distances to each of the 4 self-organizing map (SOM) patterns (Fig 6) identified as characterizing the dominant mesoscale eddy circulation over the study area.
Dashed red lines indicate the 95% confidence level corrected for autocorrelation following [54].
Fig 8.
Distribution of the total distance (km) travelled by simulated larvae.
Fig 9.
Mean percentage of simulated larval mortality when using different low lethal temperatures for model year 5.
Shading indicates mean ± s.e.