12 research outputs found
Sustainable management of fish stock: An assessment of small-scale fishing in Greece
The aim of this study was to identify the main métiers practiced by gillnet, trammel net and combined net fishery in the Kalymnos Island. The catch was obtained every 15 days of the small-scale fleet for the period from February 2013 to May 2014 by interviews during unloading. A total 315 fishing operations were recorded. Multivariate analysis applied to either species landings composition or economic revenue. The most important métiers identified were those B. boops with gillnet, intense fishing activity during December-February and mesh size 26 mm, métier which targeting S. porcus and S. officinalis with fishing gear trammel net, intense fishing activity during April-May and mesh size 26 mm. Both of these métiers appeared high produce and income. The results of this study confirm the multi-species natural of small-scale fishing and fishing activity in the area of Kalymnos specific difference from the other area in Greece
Socioeconomic aspects and characteristics of small-scale fishery in eastern Mediterranean Sea
Small-scale fishery represents an important part of Mediterranean fishery. In order to improve the knowledge on this sector primary research was carried out in the Dodecanese fishery aiming to identify the fishery and socioeconomic characteristics, fishing activities, and to identify the small-scale fisheries métiers. Specifically, data were collected over the time period 2013-2014 by interviews aiming to characterize fleets, fishing gear used, fishing activity and socioeconomic elements and interviews during unloading aimed at catch data. The highest CPUE values were reported for Boops boops (2.38±2.93 kg/1500 m net*day) caught by gillnet in the winter season, Xiphias gladius (101.03±86.06 kg/800 hooks*day) by drifting longline in the spring season. The catch is traded in both the wholesale and the retail market. The most important métiers with fishing gear and target species: gillnet, B. boops, trammel net, Scorpaen porcus and Mullus surmuletus, set longline, Pagellus erythrinus, Pagrus pagrus, Diplodus sargus, drifting longlines, X.gladius and handlines, Octopus vulgaris. The Dodecanese fishery need management measures to protect fishery resources and maintain small-scale fishery
Small-scale fishery of the Eastern Mediterranean Sea: A case study in the Kalymnos Island, Greece
This study analyzes the small-scale fishery in Kalymnos Island (located in Eastern Mediterranean Sea) to evaluate fishing practices in this fishery. The métiers of this fishery are defined with a multivariate analysis approach for assessing the main fishery resources and fishing gear employed. The empirical findings show that longlines in this fishery practice 10 types of métiers. Some of these métiers, in terms of target species, gear and seasonality are also used in other small-scale Mediterranean fisheries. The main 6 type of métiers with fishing gear: set longlines, drifting longlines, handlines and squid jig-lines with target species P.pagrus, D.vulgaris, P.erythrinus, S.aurata, X.gladius, O.vulgaris, and L.vulgaris. The seasonal rotation of métiers is determined by the availability of different fish species rather than market price. Identified the métiers provides information for developing monitoring and management strategies for the small-scale fishery. The small-scale fishery constitutes an important social component of local coastal communities
Socioeconomic aspects and characteristics of small-scale fishery in eastern Mediterranean Sea
Small-scale fishery represents an important part of Mediterranean fishery. In order to improve the knowledge on this sector primary research was carried out in the Dodecanese fishery aiming to identify the fishery and socioeconomic characteristics, fishing activities, and to identify the small-scale fisheries métiers. Specifically, data were collected over the time period 2013-2014 by interviews aiming to characterize fleets, fishing gear used, fishing activity and socioeconomic elements and interviews during unloading aimed at catch data. The highest CPUE values were reported for Boops boops (2.38±2.93 kg/1500 m net*day) caught by gillnet in the winter season, Xiphias gladius (101.03±86.06 kg/800 hooks*day) by drifting longline in the spring season. The catch is traded in both the wholesale and the retail market. The most important métiers with fishing gear and target species: gillnet, B. boops, trammel net, Scorpaen porcus and Mullus surmuletus, set longline, Pagellus erythrinus, Pagrus pagrus, Diplodus sargus, drifting longlines, X.gladius and handlines, Octopus vulgaris. The Dodecanese fishery need management measures to protect fishery resources and maintain small-scale fishery
Sustainable management of fish stock: An assessment of small-scale fishing in Greece
The aim of this study was to identify the main métiers practiced by gillnet, trammel net and combined net fishery in the Kalymnos Island. The catch was obtained every 15 days of the small-scale fleet for the period from February 2013 to May 2014 by interviews during unloading. A total 315 fishing operations were recorded. Multivariate analysis applied to either species landings composition or economic revenue. The most important métiers identified were those B. boops with gillnet, intense fishing activity during December-February and mesh size 26 mm, métier which targeting S. porcus and S. officinalis with fishing gear trammel net, intense fishing activity during April-May and mesh size 26 mm. Both of these métiers appeared high produce and income. The results of this study confirm the multi-species natural of small-scale fishing and fishing activity in the area of Kalymnos specific difference from the other area in Greece
Approaches for knowledge and application creation in logistics : an empirical analysis based on Finnish and Swedish doctoral dissertations published between 1994 and 2003
siirretty Doriast
Population Density, Size Structure, and Reproductive Cycle of the Comestible Sea Urchin Sphaerechinus granularis (Echinodermata: Echinoidea) in the Pagasitikos Gulf (Aegean Sea)
Sphaerechinus granularis is a common grazer that lives in various sublittoral habitats, displaying typical covering behavior; i.e., putts shell-fragments, pebbles, and algae on its test. It is an edible species of increasing commercial importance due to the depletion of the common urchin’s, Paracentrotus lividus, stocks. Its biology, however, is not adequately studied over its distributional range. The present study examines population density, size structure, and reproductive biology of S. granularis in the Aegean Sea. Samplings were made with SCUBA-diving (8–10 m) and included: (i) visual census along transects to estimate density, and (ii) random collection of specimens at monthly intervals to assess biometry and gametogenesis. Population density had moderate values that almost doubled when inputted to Distance software. S. granularis had larger dimensions in the sheltered site; size-structures were unimodal (65–70 mm and 70–75 mm, in exposed and sheltered site, respectively). An annual reproductive cycle was evident, according to GSI and gonads’ histology, with a clear spawning peak in early spring. This pattern conforms to previous reports from the Atlantic, but precedes those from the Mediterranean (reproduction in summer). The provided baseline knowledge on the biology of S. granularis is important for the viable management of its developing fishery
Chemical Composition and Microstructural Morphology of Spines and Tests of Three Common Sea Urchins Species of the Sublittoral Zone of the Mediterranean Sea
In the Mediterranean Sea, the species Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis often coexist, occupying different subareas of the same habitat. The mechanical and chemical properties of their calcitic skeletons are affected both by their microstructural morphology and chemical composition. The present study describes the main morphologic features and the possible temporal differences in elemental composition of the test and spines of the three species, while also determining the molar ratio of each element of their crystalline phase. Scanning electron microscopy showed major differences in the ultrastructure of the spines, while minor differences in the test were also noticed. More specifically, the spines of all three sea urchins possess wedges, however A. lixula exhibits bridges connecting each wedge, while barbs are observed in the wedges of S. granularis. The spines of P. lividus are devoid of both microstructures. Secondary tubercles are absent in the test of A. lixula, while the tests and spines of all three species are characterized by different superficial stereom. Energy dispersive x-ray spectroscopy detected that Ca, Mg, S, Na and Cl were present in all specimen. Mg and Mg/Ca showed significant differences between species both in test and spines with S. granularis having the highest concentration. The spines of P. lividus exhibited lowest values between all species. Differences between spines and test were observed in all elements for P. lividus except S. A. lixula exhibited different concentrations between test and spines for Ca, Mg and Mg/Ca, whereas S. granularis for Mg, Cl and Mg/Ca. Finally, temporal differences for Ca were observed in the test of P. lividus and the spines of S. granularis, for Mg in test of S. granularis, for S in the spines of A. lixula and the test and spine of S. granularis, for Na in the test of P. lividus and A. lixula and for Cl and Mg/Ca in the test P. lividus. Powder X-ray diffractometry determined that, out of all three species, the spines of P. lividus contained the least Mg, while the test of the same species exhibited higher Mg concentration compared to A. lixula and S. granularis. The current study, although not labeling the specimens attempts to estimate potential time-related elemental differences among other results. These may occur due to changes in abiotic factors, probably water temperature, salinity and/or pH. Divergence in food preference and food availability may also play a key role in possible temporal differences the skeletons of these specie
Temporal variations in fine sand assemblages in the North Aegean Sea (Eastern Mediterranean)
Two sites were selected in the North Aegean Sea for the study of shallow fine sand assemblages,
which are poorly known in the Eastern Mediterranean. The biomonitoring of these sites can provide
useful information on the impact of human activities on the macrofaunal and meiofaunal composition
of these assemblages. In order to examine this impact, sampling took place in five different periods
between 2000 and 2001. The qualitative and quantitative compositions of the communities at the two
sites showed certain differences, mostly between the sites and the year of sampling rather than between
sampling periods, which would be the expected outcome. The communities seem to be affected by a
combination of the human activities with the particular hydrodynamics of the studied sites
Microbial and Physicochemical Status of Raw and Processed Sea Cucumbers from the Hellenic Seawaters
The aquatic environment is a reservoir of many species that have not yet been exploited at a global level and have not been extensively investigated. The aim of the present work was to study the microbial populations, the bacterial communities and physicochemical parameters (pH, water activity, humidity, salinity) in raw, frozen, boiled, dehydrated and salted final products of two sea cucumber species (Holothuria polii and Holothuria tubulosa) originating from the Hellenic seawaters. The results indicated that all products were found at acceptable levels from a microbiological point of view. The metabarcoding analysis of the 16S rRNA gene revealed the existence of several different bacterial groups, the presence and abundance of which were mainly dependent on product type, even though some moderate differences in the microbiota profile between the two sea cucumber species were also detected in some of the products. Overall, the present work deals with an underexplored aquatic product and provides novel and useful information for the aquatic food industry, consumers and other stakeholders, increasing, in parallel, the need for further scientific attention in the near future. Our findings could be exploited as a baseline to highlight a promising aquatic food product provided to the international market