Sessile Benthic Assemblages in Northern Crete assessed from Photographic Quadrats (2008–2024)
Citation
Rallis I, Chatzigeorgiou G, Skouradakis G, Vernadou E, Polychroni T, Pavlidis D, Papagiannopoulos G, Dailianis T (2025). Sessile Benthic Assemblages in Northern Crete assessed from Photographic Quadrats (2008–2024). Institute of Marine Biology, Biotechnology and Aquaculture - Hellenic Centre for Marine Research, Greece. https://marineinfo.org/doc/dataset/8884
Contact:
Dailianis, S. ;
Availability:
 This dataset is licensed under a Creative Commons Attribution 4.0 International License.Description
This dataset contains sessile benthic coverage data derived from photographic quadrat samples collected in two time periods (2008–2009 and 2024) at two coastal sites in Northern Crete: Alykes (Heraklion) and Elounda Bay (Agios Nikolaos). Sampling was conducted along two transects per site at five depths (1 m, 5 m, 10 m, 15 m, and 20 m), using two quadrat sizes (25×25 cm and 100×100 cm) to capture replicate images. The data offer valuable insights into temporal shifts in sessile organism communities, highlighting changes potentially linked to climate change and the increasing presence of invasive herbivorous fish species, such as siganid fish and diademid sea urchins. more
Sampling was conducted through non-destructive underwater photographic surveys of fixed-area quadrats. Two permanent transects were established in each study area (Alykes and Elounda) and sampled at five depths (1, 5, 10, 15, and 20 meters) during spring seasons of 2008, 2009, and 2024. At each depth, five photographic quadrats (either 25×25 cm or 100×100 cm) were positioned along the transects on hard substrates. Each image was later analysed using a stratified point count method with 100 randomly distributed points per photo to estimate the percent cover of sessile macrobenthic taxa. The study was conducted in northern Crete, specifically in the coastal areas of Alykes and Elounda. Sampling took place during the spring seasons of 2008, 2009, and 2024, with two transects surveyed per site each year across five depth zones (1, 5, 10, 15, and 20 meters). The study focuses on hard substrate habitats and is representative of typical rocky reef environments in the eastern Mediterranean. Lineage
Prior to publication data undergo quality control checked which are described in https://github.com/EMODnet/EMODnetBiocheck?tab=readme-ov-file#understanding-the-output Scope Themes: Biology > Benthos Keywords: Marine/Coastal · Benthos · Bio-geographical regions · Biota · Environment · Epibenthos · Geoscientific Information · Habitats and biotopes · MED, Aegean · MED, Eastern Mediterranean · Metadata non conformant · Metadata not evaluated · No limitations to public access · Oceans · Reefs · Sea regions · Sessile organisms · Sublittoral zone · WGS84 (EPSG:4326) · XYZ ASCII · EurOBIS calculated BBOX · Crete Sea · Ascidiacea · Chlorophyta · Cirripedia · Cnidaria · Mollusca · Ochrophyta · Polychaeta · Porifera · Rhodophyta Geographical coverage EurOBIS calculated BBOX Stations
Bounding Box Coordinates: MinLong: 24,9876; MinLat: 35,2506 - MaxLong: 25,7589; MaxLat: 35,4158 [WGS84] Crete Sea [Marine Regions] Temporal coverage
1 June 2008 - 30 June 2024 Taxonomic coverage
Parameter
Area of sample {sampled area} from the bed [BODC] (EurOBIS harvested data) Contributors
Hellenic Centre for Marine Research (HCMR), more, data manager
Related datasets
Published in: EurOBIS: European Ocean Biodiversity Information System, more Project
MARBEFES: MARine Biodiversity and Ecosystem Functioning leading to Ecosystem Services, more
Funding Horizon Europe
Grant agreement ID 101060937
URLs
Dataset information: Other: Data type: Data
Release date: 2025-06-17
Metadatarecord created: 2025-07-15
Information last updated: 2026-01-26
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