Fig 1.
Study area and the acoustic receiver array.
Black triangles correspond to acoustic receivers placed in May 2007 and white triangles to the receivers placed in September 2008. Dotted circles represent the average detection range (150 m). Red bold letters stand for the Diplodus sargus capture locations: TAS, Tascons; POR, Portitxol; ARQ: Arquets; FAL: Falaguer. The topographic base map (1:5.000) and the sea bottom bionomic map [35] are freely accessible through the Institut Cartogràfic i Geològic de Catalunya (www.icgc.cat) under Creative Commons Attribution License (CC BY 4.0).
Fig 2.
Daily presence-absence plot of tagged Diplodus sargus within the monitored area.
Colours represent the different protection zones of the MPA; Red: no-take zone (NT), Blue: partial reserve (PR), Green: no-reserve (NR). Fish tag and release dates (blue circles), expected transmitter battery dead dates (red squares) and the final withdrawal of the receiver array (vertical green line) are shown.
Table 1.
Summary of the monitoring information of tagged Diplodus sargus.
DD: Detection Days; TP: total Tracking Period (d); RI: Residence Index, CA: Core Area; HR: Home Range.
Fig 3.
Mean spatial Utilization Distribution estimates of Diplodus sargus, for each capture location.
The concentric polygons represent, from inside out, the areas covering the 50% (core area), 75%, 90%, and 95% (home range) of the volume of the Utilization Distribution computed by the Brownian Bridge Movement Model. The topographic base map (1:5.000) is freely accessible through the Institut Cartogràfic I Geològic de Catalunya (www.icgc.cat) under Creative Commons Attribution License (CC BY 4.0).
Fig 4.
Utilization Distribution Overlap Index (UDOI) calculated for each pair of Diplodus sargus individuals.
Yellow blocks represent high UDOIs observed when comparing individuals captured in the same location. Green and blue blocks represent lower degrees of overlap and the purple areas represent no-overlapping HRs.
Fig 5.
Spatial chronogram plot for one tagged Diplodus sargus individual (#14), showing a clear diel movement pattern.
This individual was observed at receivers 5, 6 and 7 during the day (green areas) and moved to receivers 9 and 10 during the night. Some punctual excursions to receivers 12, 13 and 14 are visible in December, March and April. White areas represent 30 min intervals with no receptions. See Fig 1 for the placement of the receivers.
Fig 6.
Distribution of phase-transition values (PT) calculated for the mean depth between consecutive day-night (A) and day-day (B) phases, for each Diplodus sargus individual. Lower and upper boundaries of the boxes represent the first and third quantiles of value distributions. Significant results of the Wilcoxon signed-rank tests against the null hypothesis of a median of zero are expressed by the symbols above the boxes; +: p < 0.05; *: p < 0.01.
Fig 7.
Daily mean sea surface temperature and wave height (A) and percentages of fish observed at different depths (B) and distances from their HR boundary (C). Red lines in the back point out days in which extraordinary activities were detected by the cluster analysis. Dotted black rectangles highlight periods with recurrent high wave conditions.
Fig 8.
Metric multidimensional scaling analysis depicting similarities between days in fish occurrence at different depths and distances-to-HR.
The two main groups of days detected by the cluster analysis (ordinary and extraordinary) are shown in different colours.