Sastav prehrane i preklapanja prehrambenih navika kod 43 vrste riba u sjevernom Egejskom moru, Grčka

This study presents the diet composition of 43 of some of the most abundant fish species from the North Aegean Sea, Greece. According to the diet analysis and fractional trophic level previously reported in the literature, 20 of the studied species were omnivores with a preference for animals and the other half were carnivores (15 with preference for fish and Cephalopoda, and seven with preference for fish and Decapoda), whereas Parablennius gattorugine was the only recorded omnivore with a preference for plant material. Finally, according to the results of Schoener’s index, diet overlap between species was recorded in a small number of cases (33 out of the 903 pairs examined). Yet, competition among diet-overlapping species may be minimised by either morphological differentiations and/or habitat segregation.Ova studija bavi se sastavom prehrane 43 vrste koje spadaju u neke od najbrojnijih vrsta riba u sjevernom Egejskom moru, Grčka. Prema analizi prehrane i razine frakcijskih trofičkih razina o kojima se prije izvještavalo u literaturi, 20 vrsta od ukupnog broja istraživanih su svežderi koji preferiraju životinje, a druga polovica su mesojedi (15 od kojih preferira ribe i glavonošce, a sedam ih preferira ribe i deseteronošce) dok je Parablennius gattorugine jedini zabilježeni svežder koji preferira biljke. Naposljetku, prema rezultatima Schoenerova indeksa, preklapanja prehrambenih navika zabilježena su kod malog broja slučajeva (33 od 903 ispitivana para). Ipak, konkurencija među vrstama kod kojih se prehrambene navike preklapaju može se umanjiti bilo morfološkim diferencijacijama bilo segregacijom staništa

Prehrana i hranilišta traglja Spicara maena i gire S. smaris (Pisces, Osteichthyes, Centracanthidae) u sjevernom dijelu Egejskog mora

n the present paper we studied the diet of two centracanthid species , Spicara maena and S. smaris,in the N Aegean Sea. Overall, 282 and 118 individuals were examined, respectively. Both species preyed upon zooplankton, notably Copepoda (54.3 and 63.5%, respectively). S. maena included in its diet a wider variety of food items (36 taxa) compared to S. smaris (12 taxa). The individual trophic levels for both species ranged from 3.00 to 4.50 (mean values ± strandard error: 3.21±0.058 for S. maena and 3.05±0.068 for S. smaris ). Given their trophic position and local abundance, they play a crucial role in the flux of energy from low to high trophic levels of the Aegean benthic and pelagic food webs.U ovom radu prikazani su rezultati istraživanja prehrane dviju vrsta iz porodice girovki, traglja Spicara maenai gire S. smaris, sa sjevernog područja egejskog mora. Istraženo je 282 jedinki traglja te 118 jedinki gire. Obje vrste u svojoj prehrani koriste zooplankto, osobito veslonošcec opepoda (54.3% tragalj, 63.5% gira). Tragalj u svojoj prehrani koristi znatno širi raspon organizama (36 svojti) dok gira znatno manje (12 svojti). Pojedinačna trofička razina za obje vrste se kreće od 3.00 do 4.50 (srednja ijednost±standardna pogreška: 3.21±0.058 za traglja i 3.05±0.068 za giru).glede njihove trofičke razine i lokalne brojnosti, obje vrste igraju značajnu ulogu u protoku energije od najnižih do najviših trofičkih razina u e gejskom moru u okviru pelagijskog i bentoskog lanca prehrane

Prehrana i hranilišta traglja Spicara maena i gire S. smaris (Pisces, Osteichthyes, Centracanthidae) u sjevernom dijelu Egejskog mora

n the present paper we studied the diet of two centracanthid species , Spicara maena and S. smaris,in the N Aegean Sea. Overall, 282 and 118 individuals were examined, respectively. Both species preyed upon zooplankton, notably Copepoda (54.3 and 63.5%, respectively). S. maena included in its diet a wider variety of food items (36 taxa) compared to S. smaris (12 taxa). The individual trophic levels for both species ranged from 3.00 to 4.50 (mean values ± strandard error: 3.21±0.058 for S. maena and 3.05±0.068 for S. smaris ). Given their trophic position and local abundance, they play a crucial role in the flux of energy from low to high trophic levels of the Aegean benthic and pelagic food webs.U ovom radu prikazani su rezultati istraživanja prehrane dviju vrsta iz porodice girovki, traglja Spicara maenai gire S. smaris, sa sjevernog područja egejskog mora. Istraženo je 282 jedinki traglja te 118 jedinki gire. Obje vrste u svojoj prehrani koriste zooplankto, osobito veslonošcec opepoda (54.3% tragalj, 63.5% gira). Tragalj u svojoj prehrani koristi znatno širi raspon organizama (36 svojti) dok gira znatno manje (12 svojti). Pojedinačna trofička razina za obje vrste se kreće od 3.00 do 4.50 (srednja ijednost±standardna pogreška: 3.21±0.058 za traglja i 3.05±0.068 za giru).glede njihove trofičke razine i lokalne brojnosti, obje vrste igraju značajnu ulogu u protoku energije od najnižih do najviših trofičkih razina u e gejskom moru u okviru pelagijskog i bentoskog lanca prehrane

Nova saznanja o prehrani lesepsijske žutopjegave četverozupke Torquigener flavimaculosus Hardy i Randall, 1983. u istočnom Sredozemlju

The stomach contents of 104 individuals of Torquigener flavimaculosus from Cyprus were examined. The analysis revealed that it is an omnivorous species with a preference to animal prey, especially invertebrates with limited mobility (crustaceans, molluscs, echinoderms). The study of the length-weight relationship indicated a negative allometric growth for both sexes. It seems that its preference to consume invertebrates, its high toxicity due to high concentrations of tetrodotoxin in its tissues and some other biological characteristic reinforce it characterization as invasive and monitoring actions should be designed for such species.Istraživan je sadržaj želudca 104 jedinke Torquigener flavimaculosus sa Cipra. Analizom je utvrđeno da se radi o svejedu u čijoj prehrani prevladava životinjski plijen, posebice beskralješnjaci ograničene pokretljivosti (rakovi, mekušci, bodljikaši). Istraživanje odnosa dužine i mase tijela pokazalo je negativan alometrijski rast za oba spola. Čini se da njegova sklonost konzumiranju beskralježnjaka, visoka toksičnost zbog visokih koncentracija tetrodotoksina u tkivima i neke druge biološke karakteristike pojačavaju njegovu karakterizaciju kao invazivne vrste, pa stoga za takve treba osmisliti mjere praćenja i kontrole

Risk assessment of Golani’s round herring (Etrumeus golanii) in the Greek seas (northeastern Mediterranean Sea)

Greek waters are the recipient of several alien species, mainly through natural dispersal following invasion and establishment of non-indigenous species (NIS) in neighboring areas, making their monitoring and mitigating their effects of paramount importance. The European Union legislation framework toward alien species invasions considers risk assessments as the top of the spear for a first assessment of NIS and their potential to become invasive or not. The Union List has already included top priority species, with very few marine species. Golani’s round herring (Etrumeus golanii) is a species of round herrings in the family Dussumieriidae, a Lessepsian migrant and belonging to a group of NIS in the Mediterranean basin that are less studied. Its distribution range is mainly limited in the southeastern Mediterranean Sea, while in the Greek seas, it has not yet been observed in the north Aegean and Ionian seas, probably due to temperature and oceanographical reasons. Its presence in the basin is recorded by commercial fisheries landings in several countries (especially purse-seiners), indicating a potentially positive effect on commercial fisheries. A risk assessment of E. golanii in Greek waters was carried out in this work, based on the Risk Assessment Scheme developed by the GB Non-Native Species Secretariat (GB Non-Native Risk Assessment—GBNNRA). An overall semi-quantitative summary of risk, in terms of likelihood of events and magnitude of impacts, was facilitated for several attributors, including confidence levels for each one. The assessment highlighted a very likely possibility of introduction in the Greek seas from neighboring countries, as well as successful establishments of populations with high confidence levels. A moderate magnitude of impact regarding its further spread was deemed, while a minor one was indicated in terms of native species pressure and a minimal one in terms of economic costs and public health. Overall, E. golanii was not characterized as an invasive alien species (IAS) and local communities could benefit from its presence (commercial fisheries); however, further studies focusing on its reproduction and spawning grounds should be implemented

HELLAS-ALIENS. The invasive alien species of Greece: time trends, origin and pathways

The current paper presents the first effort to organize a comprehensive review of the Invasive Alien Species (IAS) of Greece. For this purpose, a database was developed with fields of information on the taxonomy, origin, ecology and pathways of introduction of terrestrial, freshwater and marine species. Our database includes a) taxa in the Union’s list that are present in Greece, b) taxa already present in Greece and considered to be invasive, and c) taxa highly likely to enter Greece in the next 10 years and become invasive. The Database served as the starting point for the compilation of the National List of Alien Invasive Species (HELLAS-ALIENS) in compliance with the EU Regulation 1143/2014. Overall, the HELLAS-ALIENS comprises 126 species, i.e. 32 terrestrial and freshwater plant species, 14 terrestrial invertebrates, 28 terrestrial vertebrates, 30 freshwater fishes and invertebrates and 22 marine species. Terrestrial invertebrates, birds and mammals are mainly of Asiatic origin. Most of the terrestrial plants have their native geographical distribution in the Americas (North and South). Most of the freshwater invertebrates and fishes are of North American origin, while the majority of the marine species are of Indo-Pacific origin. The first records of IAS concern terrestrial plant species, and date back to the 19th century, while those in freshwater and marine ecosystems seem to have been systematically recorded some decades later. Regarding the pathways of introduction, most of the taxa arrived in Greece or are expected to arrive through escape from confinement and unaided. The majority of the terrestrial, freshwater and marine species have been evaluated as of High-risk for the indigenous biodiversity and only 3% of the species listed have been evaluated of Low-risk. Our results provide an important baseline for management and action plans, as required by the priorities set by the European Union through the Biodiversity Strategy for 2030