Aim: We examine fish invasions in the south-eastern Mediterranean as a model system for the invasibility of open coasts and provide perspectives through a review of global marine fish invasions. ...Location: South-eastern Mediterranean (Levant Sea). Methods: We compare historical (1990—1994) and modern (2008—2011) trawl surveys from the Mediterranean continental shelf and upper slope of Israel to evaluate the relative abundance and biomass of Indo-Pacific fishes and their impact on diversity and trophic level (TrL). We examine resultant changes in community composition by both univariate and multivariate analyses, and compliment this study with a critical global review of open coast marine fish invasions. Results: A staggering 55 Indo-Pacific fish species have established permanent populations in the Mediterranean in the last 142 years, more than any other marine ecosystem. This process is accelerating with 13 of 27 new arrivals having established in the 21st century alone. Invasive fish biomass and abundance proportions in the shallow open coast have doubled in just two decades and today the Levantine ecosystem is dominated by non-native species. This proliferation has resulted in significant declines of some indigenous species, some to near extirpation levels. Main conclusions: Here, we show that non-estuarine ecosystems are much more susceptible to large-scale invasion pressures than previously thought. Our results place invasion in the same category with overexploitation, habitat destruction and pollution, processes normally considered as much more critical perturbations to coastal fish communities. We propose that despite these irreversible alterations, invasions have masked overall TrL changes and diversity declines by replacing native fish with invasives of similar ecological position. As species extirpations increase, we anticipate further declines in indigenous biomass, abundance and diversity in the Mediterranean Sea.
A good understanding of the mechanisms and magnitude of the impact of invasive alien species on ecosystem services and biodiversity is a prerequisite for the efficient prioritisation of actions to ...prevent new invasions or for developing mitigation measures. In this review, we identified alien marine species that have a high impact on ecosystem services and biodiversity in European seas, classified the mechanisms of impact, commented on the methods applied for assessing the impact and the related inferential strength, and reported on gaps in available information. Furthermore, we have proposed an updated inventory of 87 marine species in Europe, representing 13 phyla, which have a documented high impact on ecosystem services or biodiversity. Although there is no doubt that invasive species have modified marine ecosystems, evidence for most of the reported impacts is weak, as it is based on expert judgement or dubious correlations, while only 13% of the reported impacts were inferred via manipulative or natural experiments. A need for stronger inference is evident, to improve our knowledge base of marine biological invasions and better inform environmental managers.
Biological invasions are increasingly creating ecological and economical problems both on land and in aquatic environments. For over a century, the Mediterranean Sea has steadily been invaded by ...Indian Ocean/Red Sea species (called Lessepsian invaders) via the Suez Canal, with a current estimate of ~450 species. The bluespotted cornetfish, Fistularia commersonii, considered a ‘Lessepsian sprinter’, entered the Mediterranean in 2000 and by 2007 had spread through the entire basin from Israel to Spain. The situation is unique and interesting both because of its unprecedented rapidity and by the fact that it took this species c. 130 years to immigrate into the Mediterranean. Using genome scans, with restriction site‐associated DNA (RAD) sequencing, we evaluated neutral and selected genomic regions for Mediterranean vs. Red Sea cornetfish individuals. We found that few fixed neutral changes were detectable among populations. However, almost half of the genes associated with the 47 outlier loci (potentially under selection) were related to disease resistance and osmoregulation. Due to the short time elapsed from the beginning of the invasion to our sampling, we interpret these changes as signatures of rapid adaptation that may be explained by several mechanisms including preadaptation and strong local selection. Such genomic regions are therefore good candidates to further study their role in invasion success.
The filamentous flounder Arnoglossus nigrofilamentosus n. sp. is described from four specimens collected in the southeastern Mediterranean near Tel-Aviv, Israel on 5 May 2017. The new species is ...characterized as follows: second to sixth dorsal-fin rays elongate and filamentous, dorsal-fin rays 78-84, anal-fin rays 61-66, pectoral-fin rays on ocular side 12-13, on blind side 7-9, caudal-fin rays iii,11,iii , lateral-line scales 52-54, gill rakers 0 + 4-5, not serrated, interorbital a narrow bony ridge without scales in the middle, interorbital width 11% to 16% of upper orbit diameter, no enlarged teeth anteriorly in upper jaw, and prevomer small, not enlarged, weakly projecting into mouth cavity; body in fresh specimens pale (may have been dark before the epidermis was abrased), head, peritoneum and vertical fins black. The new species is described and compared with similar species. Though the species has not yet been observed in the northern Red Sea, it probably originates from the Gulf of Suez, so this finding represents a probable new case of Lessepsian migration.
Freshwaters are a very valuable resource in arid areas, such as Mediterranean countries. Freshwater systems are vulnerable ecological habitats, significantly disturbed globally and especially in arid ...areas. The Sea of Galilee is the largest surface freshwater body in the Middle East. It is an isolated habitat supporting unique fish populations, including endemic species and populations on the edge of their distribution range. Using the Sea of Galilee for water supply, fishing and recreation has been placing pressure on these fish populations. Therefore, efficient monitoring and effective actions can make a difference in the conservation of these unique fish populations. To set a baseline and develop molecular tools to do so, in this study, DNA barcoding was used to establish a database of molecular species identification based on sequences of Cytochrome C Oxidase subunit I gene. DNA barcodes for 22 species were obtained and deposited in Barcode of Life Database. Among these, 12 barcodes for 10 species were new to the database and different from those already there. Barcode sequences were queried against the database and similar barcodes from the same and closely related species were obtained. Disagreements between morphological and molecular species identification were identified for five species, which were further studied by phylogenetic and genetic distances analyses. These analyses suggested the Sea of Galilee contained hybrid fish of some species and other species for which the species definition should be reconsidered. Notably, the cyprinid fish defined as Garra rufa, should be considered as Garra jordanica. Taken together, along with data supporting reconsideration of species definition, this study sets the basis for further using molecular tools for monitoring fish populations, understanding their ecology, and effectively managing their conservation in this unique and important habitat and in the region.
The scorpionfish Scorpaena decemradiata n. sp. is described from off the coast of Israel in the Gulf of Aqaba, northern Red Sea. The new species is similar to S. porcus Linnaeus, 1758, but is ...characterized by dorsal fin spines XII, soft dorsal fin rays 10 (the last divided at base); pectoral fin rays 16, uppermost branched pectoral fin ray is the second; lacrimal with 2 spines over maxilla that point at nearly right angle from each other, the posterior pointing ventrally and slightly anteriorly; occipital pit well developed; anteriormost mandibular lateral-line pores small, separated; scales ctenoid; 59-62 scale rows in longitudinal series; scales absent on chest and pectoral fin base; and cirri developed over entire head and body, but no cirri on lower jaw. An updated checklist of the species of the genus Scorpaena Linnaeus, 1758 and a key to the species of the eastern Atlantic, Mediterranean Sea and Red Sea are presented.
This checklist of the Mediterranean fishes of Israel enumerates 469 species which is an addition of 62 species since the previous checklist of 2005. This new checklist includes 58 Condrichthys and ...411 Osteicthys species. Most newly-recorded species are of Red Sea origin (Lessepsian migrants)-38 species, 25 species are from previously poorly investigated habitats, mainly deep water, while two species reached the Mediterranean most likely by ballast water and two are aquaculture escapees. The dramatic increase in the number of Lessepsian migrants (an average of 2.5 species per year) is most likely due to the increased water influx between the Red Sea and the Mediterranean, following the recent opening of the new parallel, 72 km, "new canal" and the enlargement of other parts of the Suez Canal.
The sea bream Diplodus levantinus n. sp. is described from off the coasts of Israel in the eastern Mediterranean Sea, where it replaces Diplodus sargus (Linnaeus, 1758). The new species is ...characterized by 11-12 spines and 10-16 soft rays in the dorsal fin, 3 spines and 11-13 soft rays in the anal fin, 15-17 pectoral fin rays, 6-9 + 8-12 gill rakers on the first gill arch, upper and lower jaws with a single row of 4 incisors on each side, followed by a total of 16-19 molariform teeth in the upper jaw and 12-14 molariform teeth in the lower jaw, with the molariforms of the upper jaw separated from the incisors by a wide, toothless gap, and the sides of the body in adults with 8 vertical bars of equal width which are present even in large adults, followed by a broad bar on the caudal peduncle which usually nearly reaches the ventral margin of the caudal peduncle. An updated checklist of the species of the genus Diplodus, and a key to species of the Diplodus sargus species group from the eastern Atlantic and Mediterranean Sea, are presented.
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