Drosos Koutsoubas - Profile on Academia.edu (original) (raw)

Papers by Drosos Koutsoubas

Indo-Pacific origin Gastropod species in the Aegean Sea. Melibe fimbriata Alder and Hancock, 1864 a new invader

Fisheries Research, Apr 1, 2006

Time series analysis techniques (ARIMA models), artificial neural networks (ANNs) and Bayesian dy... more Time series analysis techniques (ARIMA models), artificial neural networks (ANNs) and Bayesian dynamic models were used to forecast annual loliginid and ommastrephid landings recorded from the most important fishing ports in the Northern Aegean Sea (1984Sea ( -1999)). The techniques were evaluated based on their efficiency to forecast and their ability to utilise auxiliary environmental information. Applying a "stepwise modelling" technique, namely by adding stepwise predictors and comparing the quality of fit, certain inferences concerning the importance of the predictors were made. The ARIMA models predicted the test data very precisely (high R 2 ), especially if the target time series contained a strong autoregressive character, after they were first differenced to obtain stationarity (R 2 > 0.96). The disadvantage of the ARIMA, as with most statistical models, is their assumption that the relationships and system parameters remain the same across the observation and forecasting periods. The influence of temperature on catches was mainly investigated by applying neural models, which predicted the monthly landings with high precision (R 2 = 0.89), even when incorporating in the model exclusively monthly SST descriptors. Similarly, ANN models of annual landings containing monthly mean temperatures provided high precision (R 2 = 0.87) and valuable inference concerning the possible effect of the SST in certain months. Bayesian dynamic models also provided a high precision (R 2 = 0.96). They combined the information of both environmental and landing time series, namely the monthly mean temperatures and the monthly seasonality of the landings. The impact factors estimated from the model have the form of time series representing the temperature effect. The results reveal that both the monthly and the annual landings can be predicted and that the Bayesian model is the best performer overall, characterised by a higher number of stable forecasts, and forecasts with higher precision and accuracy, than the other methods. It is evident, from application of the "stepwise modelling" technique, that the incorporation of temperature descriptors can significantly improve the model performance.

Journal of Molluscan Studies, Aug 1, 1999

The discovery in 1996 1 of a new strain of Neotricula aperta in central Laos raised questions as ... more The discovery in 1996 1 of a new strain of Neotricula aperta in central Laos raised questions as to the possibility of schistosomiasis in the area. The snails, here referred to as taxon XBF, were found in the Xé-Bang-Fai river of Khammouanne Province, Laos. Schistosoma mekongi is not known in central Laos. However, Mekong schistosomiasis is common in humans in the Mekong river of southern Laos at Khong Island 2 , some 480 km downstream of the XBF colony. The Xé-Bang-Fai river is a tributary of the Mekong. Neotricula aperta was first reported from the region around Khong Island and was called Lithoglyphopsis aperta Temcharoen, 1971 3 . However, no detailed anatomical descriptions were provided and it is unclear which of the three strains (␣, ␤ and ␥) 4 , now commonly referred to in the literature, was involved. Re-examination of the holotypes suggested the ␣-strain, and the type locality was recorded as Ban Na on Khong Island, Laos 4 . The presence of the ␣-strain at Khong Island has not been substantiated, although the ␥-strain is common there. In addition, the types deposited by Temcharoen (shells only) are in poor condition and could in fact be Manningiella conica, a sympatric species resembling N. ␣-aperta (Manningiella is a synonym of Hubendickia 5 .). Consequently, and for reasons of convenience, N. ␥-aperta from Khong Island is used as the taxon of reference for N. aperta until the taxonomic history has been clarified. Davis (1980) referred to L. aperta as Tricula aperta on the basis of both shell and radula characters 5 . In 1986, T. aperta was transferred to Neotricula on the basis of

Crustaceana, 1992

A new symbiotic association Sagartiogeton undatus (Müller) -Pagurus excavatus (Herbst) is describ... more A new symbiotic association Sagartiogeton undatus (Müller) -Pagurus excavatus (Herbst) is described from the Egean Sea (Eastern Mediterranean). Although not very significative of the circalittoral zone where the association Calliactis parasitica (Couch) -Pagurus excavatus (Herbst) is prevailing, it may be considered as characteristic of the bathyal zone where the average pagurid biomass is reduced. Allometric analyses have shown that the adaptation of the population of the small-sized pagurids is not due to a high social status of some pagurids but to an autoprotective behaviour against predation.

Continental Shelf Research, 2012

Beachrocks are common coastal formations, constructed through the lithification of beach sediment... more Beachrocks are common coastal formations, constructed through the lithification of beach sediments by carbonate cements. The objectives of the present contribution were to (a) assess the impacts of beachrock benthic communities on nearshore wave dynamics; (b) present a numerical model, developed to simulate wave propagation over shallow nearshore waters characterized by both loose sediment beds and colonized/non-colonized beachrocks; and (c) discuss the structure and dynamics of beachrock macro-benthic communities in an E. Mediterranean micro-tidal beach (Vatera, Lesbos Island, NE Aegean Sea), as well as their interactions with the wave forcing. Field measurements of wave height and flow velocity were processed to assess shoaling wave energy dissipation due to bottom friction from the colonized beachrock outcrops. The equivalent Nikuradse hydraulic roughness of the beachrock surface, estimated through spectral wave attenuation calculations, was found to be around k N ¼ 0.13 m. The corresponding wave friction factors were incorporated into a wave propagation model to obtain estimates of the wave-induced bed shear stress t w acting on the beachrock benthic communities. Information about the structure and characteristics of the latter was obtained through the collection and analysis of samples from 15 stations along a beach transect, during two months of the year (April and September) and the results showed that benthic communities at the beachrock habitat were very similar to the ones typically found at NE Mediterranean hard substrates. Wave-induced bed shear stress t w values were able to explain cross-shore variations in population density and biomass, both decreasing significantly above water depths of about h ¼ 1.8-2 m. The latter values corresponded, for the studied conditions, to shear stresses of about t w ¼ 2.2 Nt/m 2 . The present findings clearly show that nearshore wave patterns not only control to a certain extent the spatial structure of the beachrock habitats, but can be also influenced by them. Thus, hydrodynamics and beachrocks habitats constitute a complex system which remains very little understood and demands for further investigation.

Global NEST International Conference on Environmental Science & Technology

This paper presents the state-of-the-art research conducted as part of EN.I.R.I.S.S.T. regarding ... more This paper presents the state-of-the-art research conducted as part of EN.I.R.I.S.S.T. regarding the emerging impact of shipping and transport to the environment. More specifically, it presents the digital platforms and services that are developed as part of the research infrastructure and are related to environmental sciences. The first is the “EcoMarpol Platform”, which caters for collecting and analyzing pollution-driven data as well as calculating the environmental imprint (atmospheric emissions, waste production, chemical pollution of marine waters and sediments) of maritime activities. This platform additionally includes the online monitoring of in-port emissions from shipping and pollution from ship-to-ship transfer operations or accidents and the environmental risk assessment management. The other platform is the “Passenger Sustainable Travel Platform”, as part of which a tool for calculating aircraft emissions (CO2 and air pollutants) will be developed and applied in the Gr...

Database on the molluscan fauna from the Mediterranean Reef Ecosystems (CorMolDB - Part I)

In the Mediterranean Sea, infralittoral and circalittoral rocky bottoms (from 15 to 120 m) are ch... more In the Mediterranean Sea, infralittoral and circalittoral rocky bottoms (from 15 to 120 m) are characterized by a biogenic habitat, named "coralligenous", formed by the concretion of calcareous organisms, mainly algal thalli, and- to a lesser extent- by animal skeletons. This complex habitat is inhabited by a rich fauna that belongs to different taxonomic groups. Sponges, bryozoans, cnidarians and ascidians are the most common sessile organisms that inhabit the area while crustacean and molluscs are the common mobile organisms. Little information on the diversity of the molluscs that thrive in the coralligenous habitat is known while this information is highly important for biodiversity management purposes. After thoroughly studying the available and accessible published literature, a database for the molluscs of the coralligenous habitat has been designed and implemented for the collection and management of this information. From its index compilation more than 511 species of molluscs have been recorded so far from the coralligenous formations, the majority of which belongs to the class Gastropoda (357 sp.) followed by the Bivalvia (137 sp.), Polyplacophora (14 sp.), Cephalopoda (2 sp.) and Scaphopoda (1 sp.). Among these, the gastropod Luria lurida (Linnaeus, 1758) and Charonia lampas (Linnaeus, 1758), the endemic bivalve Pinna nobilis Linnaeus, 1758 and the endolithic bivalve Lithophaga lithophaga (Linnaeus, 1758), are protected by international conventions.

Summary of PERMANOVA results for Eunicella cavolini population density

PLOS ONE, 2015

Tests of significance were run based on Euclidean distances for square root transformed ... more Tests of significance were run based on Euclidean distances for square root transformed data.*statistically significant differences (p<0.05).Summary of PERMANOVA results for Eunicella cavolini population density.</p

On the occurrence of Elysia gordanae Thompson & Jaklin, 1988 (Mollusca, Opisthobranchia) in East Mediterranean Sea

Marine Biodiversity, Feb 26, 2015

In the East Mediterranean, five species of the family Plakobranchidae have been recorded (Koutsou... more In the East Mediterranean, five species of the family Plakobranchidae have been recorded (Koutsoubas and Koukouras 1993; Turkmen and Demirsoy 2009). Elysia gordanae Thompson& Jaklin 1988 is a small elysiid, between 10 and 17 mm in length, and can be found in shallow waters on rocky bottoms. It feeds upon Acetabularia acetabulum (Linnaeus) P.C. Silva 1952 and other filamentous algae. In the summer of 2012, a survey was conducted in the area of Kouremenos in eastern Crete by a team of two divers in order to record the biodiversity of the shallow waters (< 10 m). By means of visual census with free diving, ten dives of two-hour fixed duration were led along predefined transects (Katsanevakis et al. 2012). The findings were recorded on waterproof paper, as this is an ideal means of writing underwater and then transferring the data safely to the laboratory. Whenever necessary, specimens were collected and transferred alive and intact in the laboratory for stereoscopic vision and in situ photography. Among the species, one specimen of Elysia gordanae Thompson & Jaklin, 1988 (Fig. 1) was found in one location. It was semi-buried at a depth of 1 m under the mud on the rocky bottom. Part of the rocky bottom was covered by a dense community of the Actiniaria Anemonia viridis (Forskal, 1775) and Acetabularia acetabulum (Linnaeus) P.C. Silva 1952. This is the first record of Elysia gordanae Thompson & Jaklin, 1988 in the East Mediterranean Sea. Other Opisthobranchia that were abundant in the region were Elysia timida (Risso, 1818) and Thuridilla hopei (Verany, 1853) while a young (60 mm) opisthobranch, Aplysia dactylomela Rang 1828, was recorded crawling among the Cymodocea nodosa (Ucria) Ascherson 1870 meadow that covers part of the gulf. The specimen is deposited in the collection of invertebrates at the Natural History Museum of Crete in 96 % alcohol (NHMC 52.114). This is the easternmost location that has been found, in a particularly oligotrophic sea compared to the type of locality in the northeastern Adriatic Sea and other locations that have been recorded thus far. The species has a color variation due to the muddy bottom, which ultimately prevents researchers and divers from detecting it easily, compared to its white counterpart with red dots known as Elysia timida (Risso, 1818), which is easily located on the rocky bottoms of the shallow waters. More intensive and intrinsically thorough research is likely to show more species that, to date, have never been recorded in the East Mediterranean.

Mediterranean Marine Science, Feb 5, 2019

Coralligenous formations are biogenic structures typical of the underwater Mediterranean seascape... more Coralligenous formations are biogenic structures typical of the underwater Mediterranean seascape. Their intricate, multi-layered species assemblages are composed of perennial, long-lived organisms, particularly vulnerable to natural or human-induced disturbances. Despite their high ecological role and conservation value, few studies have addressed these assemblages outside the NW Mediterranean. This is the first quantitative assessment of coralligenous in the N Aegean Sea (NE Mediterranean), specifically focusing on the upper bathymetric limit of assemblages that are dominated by the yellow gorgonian Eunicella cavolini. The number and percent cover of macrobenthic species were studied at depths of 18 to 35 m, using a photoquadrat method. A total of 99 benthic taxa were identified, out of which 89 perennial ones were used to investigate spatial patterns in assemblage structure, composition, and biodiversity. A mean number of 47 perennial taxa were recorded per site, with encrusting coralline algae and sponges being the dominant groups in percent cover and species number, respectively. Across the studied localities, structural complexity and community composition were overall similar, but assemblages presented distinctive differences at the site level, thus highlighting the role of local abiotic and anthropogenic factors in the shaping of the coralligenous. Compared to the rest of the Mediterranean, assemblages hosted a similar number of taxa. However, the number and percent cover of erect bryozoans were generally low, while, apart from E. cavolini, other erect anthozoan species were absent. This work provides important reference data for comparisons and monitoring at a local or Mediterranean scale.

An account of our knowledge on the opisthobranch mollusc fauna of the Aegean Sea

Bollettino malacologico., 1993

A computerized database (CorMol) on the molluscan fauna from the Mediterranean reef ecosystems: Part I, the coralligenous formations

Quaternary International, Dec 1, 2015

Abstract In the Mediterranean Sea, infralittoral and circalittoral rocky bottoms (from 15 to 120 ... more Abstract In the Mediterranean Sea, infralittoral and circalittoral rocky bottoms (from 15 to 120 m) are characterized by a biogenic habitat, named “coralligenous”, formed by the concretion of calcareous organisms, mainly algal thalli, and to a lesser extent by animal skeletons. This complex habitat is inhabited by a rich fauna that belongs to different taxonomic groups. Sponges, bryozoans, cnidarians and ascidians are the most common sessile organisms that inhabit the area, while crustacea and molluscs are the most common mobile organisms. Little information on the diversity of the molluscs that thrive in the coralligenous habitat is known, though this information is highly important for biodiversity management purposes. A database for the molluscs of the coralligenous habitat was compiled and a method implemented for the management of this information. More than 511 species of molluscs have been recorded so far from the coralligenous formations, the majority of which belong to the class Gastropoda (357 sp.) followed by Bivalvia (137 sp.), Polyplacophora (14 sp.), Cephalopoda (2 sp.) and Scaphopoda (1 sp.). Among these, the gastropod Luria lurida (Linnaeus, 1758) and Charonia lampas (Linnaeus, 1758), the endemic bivalve Pinna nobilis (Linnaeus, 1758) and the endolithic bivalve Lithophaga lithophaga (Linnaeus, 1758), are protected by international conventions.

Seasonal community structure of the molluscan macrofauna at the marine‐lagoonal environmental transition at Kalloni solar saltworks (Lesvos Island, NE Aegean Sea, Greece)

Journal of Natural History, Feb 1, 2008

Community properties of benthic molluscs as indicators of environmental stress induced by organic enrichment

Journal of Natural History, Feb 1, 2008

This study investigates the multivariate spatio‐temporal population patterns of molluscan taxocoe... more This study investigates the multivariate spatio‐temporal population patterns of molluscan taxocoenosis along an organic load gradient caused by the presence of a fish farm unit in the semi‐enclosed micro‐tidal Gera bay in the island of Lesvos (northeast Aegean), by exploring three different properties (species abundance, trophic web structure and geographic ranges) as indicators for detecting community disturbance. Results have shown that community properties related to ecosystem functioning (i.e. food web analysis) and macro‐ecological aspects (i.e. zoogeographical orientation community features) have proved to be more sensitive in detecting the effects of organic load perturbation than species abundance, thus indicating the use of such properties in environmental assessment approaches in the future.

The aim of this work was to survey the early history of bivalve mollusc exploitation and consumpt... more The aim of this work was to survey the early history of bivalve mollusc exploitation and consumption in the Mediterranean coastal areas as recorded in the classical works of Greek antiquity. All bivalve species mentioned in the classical texts were identified on the basis of modern taxonomy. The study of the works by Aristotle, Hippocrates, Xenocrates, Galen, Dioscorides and Athenaeus showed that out of the 35 exploited marine invertebrates recorded in the texts, 20 were molluscs, among which 11 bivalve names were included. These data examined under the light of recent information on bivalve exploitation showed that the diet of ancient Greeks included the same bivalve species consumed nowadays in the coastal areas of the Mediterranean. The habitats of the exploited bivalves and consequently their fishing areas were well known and recorded in the classical texts. Information on the morphology and various aspects of the biology of certain edible species was given mostly in Aristotle's zoological works, while Xenocrates and Athenaeus presented instructions and recipes on how bivalves were cooked and served. Hippocrates and Galen gave detailed information on the dietary value of bivalve molluscs, their consumption for treatment or prevention of certain diseases, and their use for the production of drugs from their shell or flesh. The data on bivalve use derived from the classical texts is in accordance with archaeological evidence of the geometric and archaic periods from Greek coastal localities.

Hydrobiologia, Aug 4, 2018

The NaGISA project (Natural Geography In Shore Areas) is a global initiative within the framework... more The NaGISA project (Natural Geography In Shore Areas) is a global initiative within the framework of the Census of Marine Life. The Mediterranean Sea has joined with 4 stations, 2 in Italy and 2 on the island of Crete, Greece. Two different sites were sampled during two consecutive years (2007 and 2008) by means of SCUBA diving. On the basis of the evidence offered by the collected material from the hard substrates of Crete, and the literature mined datasets concerning the molluscan assemblages, two main issues are investigated: (a) is the molluscan fauna sampled in the two NaGISA sites representative of the regional Mediterranean one? and (b), is the molluscan fauna sampled from the two sites randomly assembled from the regional species pool across different spatial scales? Although a strong tendency of the local molluskan composition to be randomly sampled from the regional pools at all scales, it is not possible to demonstrate with a degree of certainty whether their observed local diversity is independent of local and regional processes or if it is determined by a combination of the two acting either in concert or antagonistically.

The occurrence of Rapana venosa (Valenciennes, 1846) (Gastropoda, Thaididae) in the Aegean Sea

Bollettino malacologico., 1991

Marine Ecology Progress Series, Jul 12, 2013

Mapping survey sites is essential when studying the spatio-temporal distribution of sessile assem... more Mapping survey sites is essential when studying the spatio-temporal distribution of sessile assemblages in submarine or semi-submerged marine caves. Acquiring the necessary topographic measurements is challenging, given that underwater mapping is performed in restricted spaces and with limited time or visibility. This study presents a rapid and cost-effective method for the 3-dimensional mapping and visualization of simple marine caves, where 'simple' mainly refers to the absence of a complex dendritic network of conduits. The method can be implemented by 2 divers using a regular dive line, an inexpensive handheld echosounder, and standard diving equipment. Source data are particularly compact and designed for ease of underwater acquisition, and post-survey processing is automatically performed by the accompanying customized software. The output is a scaled 3-dimensional model of the surveyed cave, which can be viewed from any particular orientation. It can be sliced to depict the horizontal zonation patterns of benthic assemblages, or used to extract approximate estimates of passage cross-sectional area. The method can assist the sampling design of ecological studies with minimum allocation of mapping resources and help the evaluation of topographic features that may affect the spatial distribution of marine biota.

Hydrobiologia, Mar 25, 2011

Water, Aug 26, 2020

The European spiny lobster Palinurus elephas is a vulnerable species that inhabits and is harvest... more The European spiny lobster Palinurus elephas is a vulnerable species that inhabits and is harvested in the Mediterranean Sea and the adjacent Atlantic waters. The fisheries associated with the spiny lobster are mainly conducted with tangle nets, trammel nets, pots, and creels. The fishing pressure has greatly reduced their numbers, changing them from a common shallow coastal species to a largely remnant population. The relative research on the species' biology and fisheries from the eastern Mediterranean Sea is almost absent. The fishery along the Chalkidiki Peninsula, Greece, is multispecies, and fishing is conducted by a small number of artisanal fishermen mainly using trammel nets. The lobster stock-both spiny and clawed lobsters-declined significantly during the late 1980s and early 1990s, later than most cases in the Mediterranean Sea. However, data regarding the nature and status of the fishery associated with the spiny lobster in Greece are lacking. Data regarding the characteristics of the spiny regional fishery were obtained by interviews and questionnaires. Additionally, fishery surveys were conducted during the main lobster fishing season from 1 May 2017 to 31 August 2017. Sixteen species were identified (15 finfish species and one invertebrate species) as targeted. In total, 79 spiny lobsters were sampled in this study; the population's sex ratio significantly diverts from the theoretical 1:1 (χ 2 = 4.57; p < 0.05), and males were dominant. Both male and female individuals demonstrate negative allometric growth profiles. In addition, no significant differences were observed between sexes. In Greece, thus far, the knowledge and information are sporadic, limited, and/or species-specific, most of which regard finfish fisheries. Furthermore, the national legislation is rather complicated-or too generalized-thus creating great uncertainties. The in-depth knowledge and experience of fishermen should be further acknowledged and utilized, and wider collaborations among scientists, practitioners, and policy-makers should be established. The present study poses some thoughts on the effectiveness of the recent EU Landing Obligation and its contribution to the potential restoration of the species.

Indo-Pacific origin Gastropod species in the Aegean Sea. Melibe fimbriata Alder and Hancock, 1864 a new invader

Fisheries Research, Apr 1, 2006

Journal of Molluscan Studies, Aug 1, 1999

Crustaceana, 1992

Continental Shelf Research, 2012

Global NEST International Conference on Environmental Science & Technology

Database on the molluscan fauna from the Mediterranean Reef Ecosystems (CorMolDB - Part I)

Summary of PERMANOVA results for Eunicella cavolini population density

PLOS ONE, 2015

On the occurrence of Elysia gordanae Thompson & Jaklin, 1988 (Mollusca, Opisthobranchia) in East Mediterranean Sea

Marine Biodiversity, Feb 26, 2015

Mediterranean Marine Science, Feb 5, 2019

An account of our knowledge on the opisthobranch mollusc fauna of the Aegean Sea

Bollettino malacologico., 1993

A computerized database (CorMol) on the molluscan fauna from the Mediterranean reef ecosystems: Part I, the coralligenous formations

Quaternary International, Dec 1, 2015

Seasonal community structure of the molluscan macrofauna at the marine‐lagoonal environmental transition at Kalloni solar saltworks (Lesvos Island, NE Aegean Sea, Greece)

Journal of Natural History, Feb 1, 2008

Community properties of benthic molluscs as indicators of environmental stress induced by organic enrichment

Journal of Natural History, Feb 1, 2008

Hydrobiologia, Aug 4, 2018

The occurrence of Rapana venosa (Valenciennes, 1846) (Gastropoda, Thaididae) in the Aegean Sea

Bollettino malacologico., 1991

Marine Ecology Progress Series, Jul 12, 2013

Hydrobiologia, Mar 25, 2011

Water, Aug 26, 2020