Deep refuges: The distribution of marine fish in warming subtropics

In light of global climate change, identifying critical marine habitats and conserving them is essential. Marine conservation planning recommends designating cooler habitats as marine protected areas. The ‘deep-reef refugia’ hypothesis suggests that deeper, suitable habitats may allow species to undergo the evolutionary changes necessary to adapt to the growing environmental threats they face. This hypothesis has rarely been tested outside tropical ecosystems. This study, using a systematic approach, is the first to evaluate this hypothesis regarding fish communities in the East Mediterranean Sea (EMS), which is warming at an unprecedented rate. Fish were surveyed twice a year, using closed-circuit rebreather systems, from 2015 to 2022 across three rocky habitats: shallow (10 m depth, 23 % ± 11 of 1 m Photosynthetically Active Radiation, PAR), upper mesophotic (25 m depth; 8 % ± 4 of 1 m PAR), and lower mesophotic (45 m depth; 3 % ± 2 of 1 m PAR), where summer maximal temperatures reach..., Study Area
The EMS water temperatures range from 17 ℃ during the winter to over 30 ℃ when the water column is highly stratified (Ben Ezra et al. 2021). The subtidal rocky reefs along this coast are made of Kurkar (aeolian-formed sandstone), which can be found on the shelf up to 100 m in depth (Neev & Ben-Avraham, 1977), as far north as Haifa (Figure 1). From Haifa northwards, most of the reef base is limestone.
The study was performed in two sites: Sdot-Yam and Achziv (Figure 1). The Sdot-Yam rocky reefs are on outcrops of Kurkar stone, ranging from 6 to 48 m depth. The reefs of Achziv are limestone-based and located within a 100 km2 managed marine protected area on the verge of an underwater canyon formation and at a distance of 3.2 km from the nearest border of the reserve. The Sdot-Yam site is not protected from fishing. The study locations (at depths of 10 m, 25 m, and 45 m) in both sites were selected by examining their bathymetric profiles: sites with relatively..., # Data from: Deep refuges: The distribution of marine fish in warming subtropics

Dataset DOI: [10.5061/dryad.76hdr7t8x](https://doi.org/10.5061/dryad.76hdr7t8x)

## Description of the data and file structure

The underwater visual fish surveys were carried out by the Morris Kahn Marine Research Station team as a part of a long-term ecological research of the rocky reefs of the southeastern Mediterranean, starting 2015.

### Files and variables

#### File: Diet.csv

**Description:** 

'Diet' variable characterized each species’ primary food source using six categories: obligate herbivore (H), macro-invertivore (Ma), micro-invertivore (Mi), planktivore (PK), piscivore (FC), and omnivore (O). The data was based on and expanded from the dataset used by (Givan et al. 2017). NA value was given when the Diet type for this species was not found in the literature.

Givan, O., Parravicini, V., Kulbicki, M., & Belmaker, J. (2017). Trait structure reveals the processes underlying fish establishmen...,