Thanos Dailianis

Hellenic Centre for Marine Research | hcmr · Institute of Marine Biology, Biotechnology and Aquaculture

Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investig...

Although more than 600 marine caves have been recorded so far along the Greek coasts of the Aegean Sea (Eastern Mediterranean), only a few have been systematically studied for their biodiversity. In this study, the benthic communities of six marine caves within a Protected Area of South-Eastern Aegean were studied for the first time, both qualitati...

The colonization of artificial structures by benthic organisms in the marine realm is known to be affected by the general trophic patterns of the biogeographical zone and the prevailing environmental traits at the local scale. The present work aims to present quantitative data on the early settlement progress of macrofaunal benthic assemblages deve...

Restoration is considered an effective strategy to accelerate the recovery of biological communities at local scale. However, the effects of restoration actions in the marine ecosystems are still unpredictable. We performed a global analysis of published literature to identify the factors increasing the probability of restoration success in coastal...

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better healt...

Marine caves support rich biodiversity with sponges presenting an important functional role as ecosystem engineers and constituting the most representative colonizers of their darker interior. Although plenty of marine caves have been reported on the Croatian coastline, they are mostly qualitatively studied. In the current study, one semi-submerged...

The Aegean Sea is the most well-studied ecoregion about sponge diversity in the Eastern Mediterranean. However, most studies have been carried out within conventional diving depth limits (0-30 m) or with trawl nets on soft substrates. Mesophotic sponge communities on hard substrates remain essentially unexplored. In this study, benthic biodiversity...

Besides the release of organic matter from uneaten feed and fish excreta, a considerable amount of deleterious chemicals may also end up into the marine environment from intensive aquaculture. A fraction of these pollutants remains freely dissolved and pose a threat to marine life due to increased bioavailability. Given the filter-feeding ability o...

Mediterranean rocky reefs are undergoing regime shifts, from a structurally complex and diverse state dominated by canopy forming macroalgae to a degraded one characterised by low-lying turf or encrusting macroalgal species, due to increased anthropogenic pressure and climate change. Using data gathered from 89 sites across the entire Aegean Sea, t...

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,64...

In the marine environment, fish contribute to key ecological processes such as controlling food‐webs through top‐down impacts, especially on algae. To date, the assessment of fish grazing activity has mostly been performed using short‐term (<1 h) censuses by divers or remote cameras which do not allow estimating the variability of grazing rate with...

The "Guide for Marine Habitat Mapping" is the outcome of the Green Fund project entitled "Development of common methodology and techniques for marine habitat mapping". This Guide aims to provide a synopsis of the diverse array of concepts and methods used to undertake the marine habitat mapping adapted to the marine environment of the Hellenic Seas...

In the face of the biodiversity crisis, concerted efforts towards understanding the effects of climate change and habitat loss and fragmentation, both locally and globally, are urgently needed. These are often attempted by leveraging the advances of modern genomics and bioinformatics methodologies. Especially in biodiversity hotspots, the need to u...

Biological invasion is one of the main components of global changes in aquatic ecosystems. Unraveling how establishment in novel environments affects key biological features of animals is a key step towards understanding invasion. Gut microbiome of herbivorous animals is important for host health but has been scarcely assessed in invasive species....

1. Sound production represents an integral part of social communication in many teleost fish; however, few studies have investigated the structure, organization and variability of fish sounds at the community level. 2. Fish acoustic community structure was recorded simultaneously in three sites located along the Mediterranean basin within the ende...

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better healt...

Monitoring marine biodiversity in hard-bottom habitats is challenging as it typically involves resource-intensive, non-standardized, and often destructive sampling methods that limit its scalability. Differences in monitoring approaches furthermore hinder inter-comparison among monitoring programs. Standardised collectors such as Artificial Reef Mo...

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better healt...

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better healt...

Marine hard-bottom communities are undergoing severe change under the influenceof multiple drivers, notably climate change, extraction ofnatural resources, pollutionand eutrophication, habitat degradation, and invasive species. Monitoring marinebiodiversity in such habitats is, however, challenging as it typically involves expensive,non-standardize...

Marine hard-bottom communities are undergoing severe change under the influence of multiple drivers, notably climate change, extraction of natural resources, pollution and eutrophication, habitat degradation, and invasive species. Monitoring marine biodiversity in such habitats is, however, challenging as it typically involves expensive, non-standa...

Marine hard-bottom communities are undergoing severe change under the influence of multiple drivers, notably climate change, extraction of natural resources, pollution and eutrophication, habitat degradation, and invasive species. Monitoring marine biodiversity in such habitats is, however, challenging as it typically involves expensive, non-standa...

The Mediterranean endemic fan mussel Pinna nobilis is suffering an ongoing basin-scale mass mortality event (MME) since 2016. As most Mediterranean populations have collapsed, the species has been declared as Critically Endangered in the IUCN Red List of threatened species. In an effort to track the progress of the MME and provide updated informati...

• 1. The coralligenous habitat was studied at the large Mediterranean scale, by applying a standardized, non‐destructive photo‐sampling protocol, developed in the framework of the CIGESMED project. • 2. The results provided evidence to support the following statements: (a) the assemblage pattern is not homogeneously distributed across the four Medi...

Marine organisms produce a vast diversity of metabolites with biological activities useful for humans, e.g. cytotoxic, antioxidant, anti-microbial, insecticidal, herbicidal, anticancer, pro-osteogenic and pro-regenerative, analgesic, anti-inflammatory, anti-coagulant, cholesterol-lowering, nutritional, photoprotective, horticultural or other benefi...

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, b...

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, b...

Global change impacts Mediterranean fisheries and the dependent human populations. Overfishing and epizootic diseases related to extreme climatic events are currently accepted as the main threats to the production of commercial bath sponges. Believing that other factors could have impacted this insular fishery, we assembled a 150-year-long series o...

The emblematic sponge Spongia officinalis is currently threatened by recurrent mortality incidents in its native habitats. Elevated temperature has been indicated as a major triggering factor, but the molecular mechanisms recruited for the organism's response to thermal shifts are yet unknown. Here, we experimentally tested the effect of exposure t...

The administration of antibiotics in aquaculture has raised concern about the impact of their overuse in marine ecosystems, seafood safety and consumers' health. This "green consumerism" has forced researchers to find new alternatives against fish pathogens. The present study focused on 12 Mediterranean medicinal-aromatic plants as potential antimi...

Objectives: We report a transcriptome acquisition for the bath sponge Spongia officinalis, a non-model marine organism that hosts rich symbiotic microbial communities. To this end, a pipeline was developed to efficiently separate between bacterial expressed genes from those of eukaryotic origin. The transcriptome was produced to support the assess...

In marine ecosystems, sponges are ubiquitous sessile organisms that contain a wide range of specialized metabolites. These metabolites point to a diverse range of biochemical pathways. Some of these compounds are biomarkers that indicate the presence of bacteria that form symbiotic relationships with a host sponge (microsymbionts). Sponges hold con...

Passive acoustic monitoring (PAM) uses hydrophones to record all components of underwater soundscapes, including fish calls. Several studies have used PAM to investigate different aspects of vocal fish species, such as presence, distribution, relative abundance, diel, lunar and seasonal cycle of activity as well as for delimitating spawning areas a...

The present study aimed to evaluate the impact of polycyclic aromatic hydrocarbons (PAHs) produced by multiple emission sources on prokaryotic communities in sediments chronically affected by anthropogenic pressures. In this context, surface sediments were investigated in three Mediterranean touristic ports over three sampling periods and in differ...

While aquaculture is outpacing food production from capture fisheries and expected to play a major role in future economies, it exerts pressure to adjacent marine habitats mainly via the release of organic load and other substances. Among bioremediation candidates to mitigate organic pollution, sponges appear prominent due to specific traits includ...

Marine caves constitute unique biodiversity reservoirs of high conservation value. Nevertheless, marine caves of the Aegean Sea have been studied less intensively than those in other Mediterranean regions. In this study, benthic biodiversity and physicochemical parameters were investigated for the first time in the Elephant Cave of Crete (Greece),...

The Underwater Biotechnological Park of Crete (UBPC) is an applied research infrastructure established in 2015 at the island of Crete (Aegean Sea, Eastern Mediterranean), occupying a seafloor area of 2.5 hectares at depths between 18 and 22 m. Its main objectives are: (a) the continuous monitoring of coastal environmental parameters; (b) the experi...

Two decades ago, a unique marine cave was discovered in Crete (Greece, Eastern Mediterranean). The so-called Elephant Cave was very soon meant to become one of the most iconic diving destinations in the island. It stands out for its aesthetic value with a variety of speleoforms and the remaining fossil bones of deers and a dwarf elephant which are...

Sponges are organisms with simple body plan, without true tissue differentiation. Moreover, they are notorious for hosting rich, regulated symbiotic bacterial communities, thus creating the sponge holobiont. These traits, combined with the expansive and diverse nature of the poriferan phylum and the fact that only two sponge species have been seque...

Ports are open systems with direct connection to the sea, therefore any potential impact on port waters may have implications for the health of adjacent marine ecosystems. European WFD addressed ports in the category of Heavily Modified Water Bodies (HMWBs) and promoted implementation of protocols to monitor and improve their ecological status. TRI...

The Aegean Sea hosts a considerable number of marine caves, the great majority of which are located in the island-dominated South Aegean region. Herein, nine marine caves from different Aegean islands were investigated for the first time by means of SCUBA diving and non-destructive sampling (photoquadrats). A total of 70 taxa belonging to 8 taxonom...

Mediterranean marine caves remain largely unexplored, while particularly limited information is available about microbial life in these unique environments. This study is a preliminary assessment of the composition of the active anaerobic microbial community colonizing the walls of newly explored systems of underwater caves and small cavities in Za...

Artificial reefs (ARs) are submerged man-made constructions aiming to enrich the marine life of a given area providing shelter and facilitating the attraction and concentration of several taxa (Klaoudatos et al. 2012). The functional and morphological characteristics of the innovative ARs deployed by the Hellenic Centre for Marine Research (HCMR) i...

Introduction/Aim: Within the last decades several Artificial Reefs (ARs) have been deployed in the European seas as a measure for the enhancement of fish stocks and to a lesser extent for the protection and enhancement of seabed habitats (Fabi et al. 2011). The “HCMR Recreational Diving OasisTM” constitutes an innovative concept based on the constr...

Sponges are among the less-studied benthic invertebrates as regards their extinction risk and conservation status. Herein, we evaluate the regional conservation status of sponges in the Aegean ecoregion (Eastern Mediterranean Sea), using the IUCN Red List criteria. We examined 20 sponge taxa falling into three categories: i) threatened species list...

A review of 573 studies on active restoration actions in the marine environment, published in the last 25 years, was carried out at global scale. We assessed how, where, at which spatial and temporal scales and under which socio-ecological settings restoration studies have been carried out, from very shallow to deep sea habitats. Results show that...

A review of 573 studies on active restoration actions in the marine environment, published in the last 25 years, was carried out at global scale. We assessed how, where, at which spatial and temporal scales and under which socio-ecological settings restoration studies have been carried out, from very shallow to deep sea habitats. Results show that...