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Length-weight relationships ( LWR) of fish serve as building blocks in ichthyology and fishery science. In this study LWR knowledge is extended to some species, regions and sizes of fish either incomplete or missing from the literature or from the online databank ( Fish Base). For several species data are presented for the first time, while other entries are improved and expanded. Organisms were captured by trawl from the continental shelf of the Israeli coast, where fishes were hypothesized as being small due to low productivity and high water temperatures - a phenomenon called ' Levantine Nanism'. Despite this, for nine of the 43 species presented here the maximum length values exceeded their Lmax in Fish Base. The dominance of fishes of Indo-Pacific origin among the species with exceptionally large specimens (7 of 9) is in agreement with Bergmann's rule; it is thus hypothesized here that these large specimens result from the low temperatures in the Mediterranean compared to their warm Indo-Pacific sources. This is an example of the superb adaptation of tropical species to the Mediterranean and suggests that Levantine Nanism may be limited to indigenous species. [ABSTRACT FROM AUTHOR]

The ecosystems of the Israeli Mediterranean coast have undergone significant changes in recent decades mainly due to species invasions and fishing. In order to characterize the structure and functioning of the marine continental shelf of the Israeli Mediterranean coast and assess temporal changes, we developed a food web model representing two time periods: 1990–1994 and 2008–2012. The 1990–1994 and 2008–2012 food web models were composed of 39 and 41 functional groups, respectively. Functional groups ranged from primary producers to top predators, and included six and eight alien functional groups, respectively, encompassing several crustacean and fish species. Input data included local surveys and fishery statistics, published data on stomach content analyses, and the application of empirical equations to estimate consumption and production rates. Results of the competitive interactions between alien and native species and changes in trophic flows between food web components highlight the increasing impact of alien species over time. Fishing had noticeable impacts in both time periods and played an important role in the ecosystem. Despite different productivity rates and other environmental differences, the Israeli marine ecosystem shared common structural and functional traits with other Mediterranean marine ecosystems. This is the first attempt to study the ecosystem of the Levant region using mass-balance models and to integrate such a large amount of alien species into food web analyses. [ABSTRACT FROM AUTHOR]