Dužinsko-maseni odnos za 9 komercijalnih vrsta riba iz sjevernog Egejskog mora

Length-weight relationships are presented for 9 commercial fish species from Psara Island (North Aegean Sea). The species studied are Boops boops, Dentex maroccanus, Helicolenus dactylopterus, Merluccius merluccius, Mullus surmuletus, Pagrus pagrus, Raja clavata, Scyliorhinus canicula and Trachurus picturatus. To our knowledge, there are no published data on the fish stocks of the study area. Estimates of LWR parameters are provided for Dentex maroccanus, Trachurus picturatus and Helicolenus dactylopterus, for which reliable LWR datasets are few in the literature, while none has been published for the Greek seas. The samples were collected from the continental shelf and the upper slope, by using non-selective fishing gear (with a research vessel and a commercial bottom trawler), during two seasonal sampling periods: November 2009 and May 2010. The growth pattern of Boops boops and Scyliorhinus canicula was found to be positive allometric, whereas an isometric growth pattern was determined for the other species in the study. We hope that the LWR obtained here will be used in future fisheries management or conservation research in the study area, for example, to convert lengths to weights, determine fish condition and assess spatial or temporal variability in fish growth.Prikazani su dužinsko-maseni odnosi za 9 komercijalnih vrsta riba s otoka Psara (sjever Egejskog mora). Istraživane vrste su bukva (Boops boops), marokanski zubatac Dentex maroccanus, bodečnjak veliki (Helicolenus dactylopterus), oslić (Merluccius merluccius), trlja kamenjarka (Mullus surmuletus), pagar (Pagrus pagrus), raža kamenica (Raja clavata), mačka bljedica (Scyliorhinus canicula) i šarun golemi (Trachurus picturatus). Prema saznanjima, nema objavljenih podataka o ribljem fondu ovog istraživanog područja. Procjena parametara dužinsko-masenog odnosa (LWR) iznesena je za zubaca Dentex maroccanus, šaruna golemog (Trachurus picturatus) i bodečnjaka velikog (Helicolenus dactylopterus), za koje u literaturi postoje malobrojni pouzdani podaci o dužinsko-masenom odnosu, dok nema nikakvih objavljenih podataka za mora oko Grčke. Uzorci su prikupljani iz epikontinentalnog pojasa i gornjeg nagiba koristeći neselektivne ribolovne alate (istraživačko plovilo i komercijalna pridnena koćarica) tijekom dva sezonska razdoblje uzorkovanja u studenom 2009. i svibnju 2010. godine. Rast bukve i mačke bljedice alometrijski je pozitivan, dok je izometrični uzorak rasta uočen kod drugih istraživanih vrsta. Smatra se da će dužinsko-maseni odnos koji je ovdje uočen biti ubuduće korišten prilikom upravljanja ribarstvom ili prilikom konverzacijskih istraživanja u istraživanom području, primjerice pretvorbom dužine u širinu, određivanja stanja ribe i procjene prostornih i vremenskih varijabilnosti u rastu riba

Coralligenous formations dominated by Eunicella cavolini (Koch, 1887) in the NE Mediterranean: biodiversity and structure

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 the assemblages outside the NW Mediterranean. This is the first quantitative assessment of coralligenous in the N Aegean Sea (NE Mediterranean), specifically focusing at 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 level of sites 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 an important baseline for comparisons and monitoring at a local or Mediterranean scale level.

Distribution patterns of fish assemblages in an Eastern Mediterranean intermittent river

The distribution patterns of fish assemblages within streams can provide insights for river type classifications and may warrant specific conservation actions. However, there is limited knowledge of how fish assemblages assort along a longitudinal axis in Mediterranean intermittent streams. Patterns in spatial and temporal distribution of fish communities were analysed in a Mediterranean intermittent river (Evrotas River) located in Southern Greece, hosting three endemic range restricted species of high conservation concern, during the period 2007−2009, with 80% of the river’s total length desiccating in the 2007 and 2008 droughts. The general trend was an increase in fish density and species richness along an upstream-downstream gradient. Fish assemblages from upstream to downstream were characterized by a decrease of the most rheophilic species (Squalius keadicus) and an increase of the most stagnophilic species (Tropidophoxinellus spartiaticus). Three river segments, characterized by a high degree of homogeneity were delineated. Habitat and environmental preferences for the studied fish species were identified, with elevation and low flowing habitats being the most important environmental factors affecting fish distribution patterns. The current study provides evidence that even in an intermittent river an assemblage pattern following a longitudinal gradient can be identified, mainly due to the lack of instream barriers that allows recolonization after flow resumption

The yellow gorgonian Eunicella cavolini: demography and disturbance levels across the Mediterranean Sea

The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale

Space invaders; biological invasions in marine conservation planning

Aim: Biological invasions are major contributors to global change and native biodiversity decline. However, they are overlooked in marine conservation plans. Here, we examine for the first time the extent to which marine conservation planning research has addressed (or ignored) biological invasions. Furthermore, we explore the change of spatial priorities in conservation plans when different approaches are used to incorporate the presence and impacts of invasive species. Location: Global analysis with a focus on the Mediterranean Sea region. Methods: We conducted a systematic literature review consisting of three steps: (1) article selection using a search engine, (2) abstract screening and (3) review of pertinent articles, which were identified in the second step. The information extracted included the scale and geographical location of each case study as well as the approach followed regarding invasive species. We also applied the software Marxan to produce and compare conservation plans for the Mediterranean Sea that either protect, or avoid areas impacted by invasives, or ignore the issue. One case study focused on the protection of critical habitats, and the other on endemic fish species. Results: We found that of 119 papers on marine spatial plans in specific biogeographic regions, only three (2.5%) explicitly took into account invasive species. When comparing the different conservation plans for each case study, we found that the majority of selected sites for protection (ca. 80%) changed in the critical habitat case study, while this proportion was lower but substantial (27%) in the endemic fish species case study. Main conclusions: Biological invasions are being widely disregarded when planning for conservation in the marine environment across local to global scales. More explicit consideration of biological invasions can significantly alter spatial conservation priorities. Future conservation plans should explicitly account for biological invasions to optimize the selection of marine protected areas

CorMolDB

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

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 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

The rare subgroup C 1 of Marphysa (Polychaeta, Eunicidae): re-description of species and first records in the Mediterranean Sea

Katsiaras, Nikolaos, Simboura, Nomiki, Koutsoubas, Drosos (2014): The rare subgroup C 1 of Marphysa (Polychaeta, Eunicidae): re-description of species and first records in the Mediterranean Sea. Zootaxa 3873 (3): 201-217, DOI: 10.11646/zootaxa.3873.3.

The Yellow Gorgonian Eunicella cavolini: Demography and Disturbance Levels across the Mediterranean Sea

19 pages, 7 figures, 6 tables, supporting information http://dx.doi.org/10.1371/journal.pone.0126253The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale. © 2015 Sini et al.MS research activity has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds (Ministry of Education and Religious Affairs managing authority) through the Operational Program >Education and Lifelong Learning> of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund. SK received funding provided by the Croatian Ministry of Culture through the grant allocated to Marine Explorers Society –“20,000 leagues” in 2009 and by the Croatian Ministry of Science and Education (project 119-0362975-1226)Peer Reviewe