1cfb47d2-d9c9-4526-9ee9-ef144073a22c Monitoring of the sea urchin populations and macroalgal cover along the Catalan coast (Blanes, NE Spain) 2019-01-01 <p data-start="378" data-end="1003" style="white-space: normal; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">This ongoing monitoring program, led by CSIC-CEAB since 2019, assesses the structure and dynamics of rocky reef ecosystems along the Catalan Coast (NE Spain), with a focus on sea urchin populations and macroalgal cover. It aims to provide ecosystem-based management strategies for sea urchin fisheries, help prevent macroalgal forest collapse, and support the long-term resilience of benthic habitats. The program targets three macroalgal strata — crustose coralline algae (CCA), turf algae, and erect macroalgae — and quantifies the abundance of key sea urchin species including& <em data-start="958" data-end="981">Paracentrotus lividus</em>& and& <em data-start="986" data-end="1002">Arbacia lixula</em>.</p><p data-start="1005" data-end="1580" style="white-space: normal; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">Fieldwork is conducted annually at six sites along the Costa Brava, each including two sampling areas. In each area, researchers conduct two 25-meter SCUBA transects and sample 25 quadrats (40×40 cm). Benthic surveys are complemented by high-resolution UAV drone imagery and orthomosaics processed in QGIS, used to assess macroalgal cover and bare substrate across wider reef sections. Surveys are conducted in shallow rocky reefs from 0 to 10 meters depth, and include both primary producers and mesoherbivore assemblages within the Echinodermata and macroalgal communities.</p> sea urchins macroalgae Blanes Catalan coast Franz Peters Institute of Marine Sciences (CSIC) cesc@icm.csic.es Blanes 2.20 3.30 41.30 42.30