Shallow reef fish abundance and functional traits for the northeast Mediterranean sea

Chatzimentor, Anastasia 1 2 ; Doxa, Aggeliki3 4; Katsanevakis, Stelios5; Mazaris, Antonios1

Published Jul 20, 2026 on Dryad. https://doi.org/10.5061/dryad.76hdr7tb1

Data files

Jul 20, 2026 version files 13.52 KB

Data_dryad.xlsx

9.92 KB
README.md

3.59 KB

Abstract

This dataset contains original reef fish abundance data collected from shallow coastal habitats (5 m depth) in the northeastern Mediterranean Sea, including the Aegean and Ionian Seas. Data were obtained through underwater visual surveys conducted by SCUBA divers at 100 sampling stations. The dataset includes abundance summary statistics for 27 reef fish species recorded during the surveys. For each species, the dataset provides the mean abundance, standard deviation, minimum abundance, and maximum abundance across all sampling stations. These data were collected to investigate the composition of shallow reef fish communities and to support analyses of functional diversity and potential climate-related changes in Mediterranean reef fish assemblages. The functional trait information used in the associated study was obtained from external sources (e.g., FishBase and published literature) and is not included in this Dryad repository. References to the original trait data sources are provided in the accompanying README. The dataset does not contain personal or sensitive information. Fish surveys were conducted using non-destructive underwater visual survey methods, and no legal or ethical restrictions apply to the original abundance data included in this repository.

Dataset DOI: 10.5061/dryad.76hdr7tb1

Description of the data and file structure

Data were collected to investigate the functional composition of reef fish communities in the northeastern Mediterranean Sea and to evaluate potential future changes associated with climate-driven shifts in functional patterns. Reef fish abundance data were obtained through underwater visual surveys conducted by SCUBA divers at 100 shallow coastal sampling stations (5 m depth) across the Aegean and Ionian Seas.

Functional trait information used in the associated analyses was obtained from external sources and is not included in this Dryad submission.

Files and variables

File: Data_dryad.xlsx
Sheet 1: Abundance_statistics_100samplin

Description:
This file contains abundance summary statistics for 27 reef fish species recorded across 100 sampling stations in the northeastern Mediterranean Sea (Aegean and Ionian Seas).

Variables:
- Fish species: Scientific name of each reef fish species.
- Average abundance: Mean abundance value across all sampling stations (individuals per transect area).
- Standard deviation: Standard deviation of abundance values across sampling stations.
- Minimum abundance: Minimum observed abundance value across sampling stations.
- Maximum abundance: Maximum observed abundance value across sampling stations.
Units:
Abundance values represent counts of individuals recorded during underwater visual surveys and standardized per sampling effort.

Missing values:
Missing values, where applicable, are indicated as “NA”.

Code/software

The dataset files are provided in .xlsx format and can be viewed using standard spreadsheet software such as Microsoft Excel, or Google Sheets. The files can also be imported into R for statistical analyses and visualization.

Data processing and analyses were conducted in R version 4.5.1 (R Core Team, 2020) using RStudio. The following R packages were used during data processing and analyses: ‘stats’ (version 4.5.1), ‘caret’ (version 7.0-1), ‘raster’ (version 3.6-32), ‘ncdf4’ (version 1.24), ‘FD’ (version 1.0-12.3), ‘ggplot2’ (version 4.0.1), and ‘ape’ (version 5.8-1).

Spatial data visualization and mapping were additionally performed using ArcGIS 10.1.

No custom scripts or executable code files are included in this data submission.

Access information

The functional trait information used in the associated analyses was obtained from the following external sources:

Froese, R. & Pauly, D. (Editors). FishBase. World Wide Web electronic publication: www.fishbase.org (accessed April 2025).
Tzanatos, E., Moukas, C., & Koutsidi, M. (2020). Mediterranean nekton traits: distribution, relationships and significance for marine ecology monitoring and management. PeerJ, 8, e8494. https://doi.org/10.7717/peerj.8494

Environmental variables referenced in the associated study were derived from:

Kristiansen, T., Butenschön, M., & Peck, M. A. (2024). Statistically downscaled CMIP6 ocean variables for European waters. Scientific Reports, 14, 1209. https://doi.org/10.1038/s41598-024-51160-1

Users wishing to reproduce the functional trait analyses should obtain the trait data directly from the original sources and comply with the applicable licensing and citation requirements.