- +302631058422
Alexis Ramfos
University of Patras, Biology, Faculty Member
- Aquaculture and Fisheries Management, Climate Change, Fish Biology, Fisheries, Fisheries Management, Environmental Impact Assessment, and 6 moreZooplankton ecology, Coastal Lagoons, Seagrass ecology, Echosounder, Habitat Mapping, and ROV robotic(Zooplankton ecology, Coastal Lagoons, Seagrass ecology, Echosounder, Habitat Mapping, and ROV robotic)edit
- Marine Biologist PhD in Marine Biology, University of Patras MSc in Marine Biology, Fisheriesedit
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The Kotychi Lagoon (western Peloponnese, Greece), together with other coastal wetlands such as Pappas, Prokopos and Lamia, is part of the wider area of the Strofylia Wetlands National Park and Protected Areas of Western Peloponnese, which... more
The Kotychi Lagoon (western Peloponnese, Greece), together with other coastal wetlands such as Pappas, Prokopos and Lamia, is part of the wider area of the Strofylia Wetlands National Park and Protected Areas of Western Peloponnese, which has been protected by the Ramsar convention since 1971 and classified as a Natura 2000 area due to its high diversity and ecological value. This study aimed to estimate the water surface evolution of the Kotychi Lagoon using optical remote sensing techniques to record parameters and indices related to the geometrical and landscape orientation features for the 1945–2016 period and to evaluate the ecological and environmental status of the lagoon through in-situ measurement and sample analysis. High-resolution aerial photos at a scale of 1:30,000, orthomosaics, and satellite images were used and linear regression rates (LRR) were calculated to determine the changes. Seasonal sampling of water, sediment, and macrofaunal organisms in the lagoon was per...
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The sex-specific daily spawning seaward migration of striped mullet Mugil cephalus was analysed in Palaiopotamos Lagoon (western Greek coast, eastern Mediterranean Sea) in an 86 day time series. The data set included the daily number of... more
The sex-specific daily spawning seaward migration of striped mullet Mugil cephalus was analysed in Palaiopotamos Lagoon (western Greek coast, eastern Mediterranean Sea) in an 86 day time series. The data set included the daily number of M. cephalus catches in barrier traps, as well as a time series of some weather variables. The analysis revealed an important linkage of the daily migration rate as well as a sex-specific response of the species to the lunar cycle and the short-term fluctuation of weather variables. The daily migration pattern of females was more persistent than that of males, indicating a possible female leadership role during the spawning migration. Multiregression models described quite accurately the sex-specific daily migration rates of the species, thus providing a potentially powerful tool regarding the lagoon fishery management of M. cephalus, especially in the context of climate change.
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Abstract The CymoSkew index, a quantitative expression of Cymodocea’s photosynthetic leaf length (PLL) asymmetry, has been used as an early warning response indicator of coastal ecosystem status and trends. Besides its strengths, the... more
Abstract The CymoSkew index, a quantitative expression of Cymodocea’s photosynthetic leaf length (PLL) asymmetry, has been used as an early warning response indicator of coastal ecosystem status and trends. Besides its strengths, the number (N) of PLL used and the fact that they are chosen randomly, as well as the difficulty of its application in low-density meadows, were CymoSkew’s main weaknesses. A new version of the index (CymoSkewm) was developed using previous and new monitoring studies in eight meadows of the North Aegean Sea. It was also validated on another dataset carried out at six coastal and two transitional meadows and tested against MA-LUSI anthropogenic stress index. To avoid the effect of randomness on the index’s accuracy, a random subsampling resampling technique in all PLL values of a meadow has been developed, producing a large number of different subsamples of N = 20 - 300 P L L drawn without replacement from all PLL values of a meadow, in order to reconstruct the underlying theoretical distribution of the CymoSkew index and infer about the unknown population mean. The iterated process constitutes the basis for evaluating the empirical distribution of CymoSkew mean values, while the mean value of this new distribution represents the CymoSkewm meadow value, accompanied by empirical confidence intervals. In this way, low-density Cymodocea meadows can be accurately assessed, as PLL’s from the whole meadow are utilized and not from one quadrate. Both versions of the index (CymoSkew, CymoSkewm) were significantly linearly correlated together and with the MA-LUSI index (for both analyses p http://index.cymoskew.gr/ ) for the computation of Cymoskewm or CymoskewmMAX has been developed.
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SUMMARY The present study describes a novel dual digital camera system that could be used for the determination of Atlantic bluefin tuna (ABT) size (length) and number during the caging process. The system consists of an orthogonal metal... more
SUMMARY The present study describes a novel dual digital camera system that could be used for the determination of Atlantic bluefin tuna (ABT) size (length) and number during the caging process. The system consists of an orthogonal metal frame (10x10m) positioned in the fattening cage through which the transferred fish will be forced to pass. All passing fish will be video recorded by two cameras arranged perpendicularly on the side and top of the frame. The specific arrangement produces synchronized images that can be used for the accurate enumeration and size determination of the fish, two parameters that are necessary for the biomass estimation of the ABT at the initiation of the fattening process and highly sought by ICCAT towards the improvement of the management plan for the species. Technical and scientific issues concerning the application of the system as well as its advantages and disadvantages are discussed. RESUME La presente etude decrit un nouveau systeme de camera numerique double qui pourrait etre utilise pour determiner la taille (longueur) du thon rouge de l'Atlantique et son nombre pendant le processus de mise en cages. Le systeme est compose d'un cadre metallique orthogonal (10x10m) situe dans la cage d'engraissement a travers lequel les poissons transferes seront obliges de passer. Tous les poissons qui passent seront enregistres par video par deux cameras amenagees perpendiculairement sur le cote et la partie superieure du cadre. L'arrangement specifique produit des images synchronisees qui peuvent etre utilisees pour l'enumeration precise et la determination de la taille des poissons, deux parametres necessaires pour estimer la biomasse du thon rouge de l'Atlantique au debut du processus d'engraissement et fort recherches par l'ICCAT en vue d'ameliorer le plan de gestion pour cette espece. Des questions techniques et scientifiques concernant l'application du systeme ainsi que ses avantages et ses inconvenients sont discutees. RESUMEN
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The Mediterranean endemic fan mussel Pinna nobilis is suffering an ongoing basin-scale mass mortality event (MME) since 2016. As most Mediterranean populations have collapsed, the species has been declared as Critically Endangered in the... more
The Mediterranean endemic fan mussel Pinna nobilis is suffering an ongoing basin-scale mass mortality event (MME) since 2016. As most Mediterranean populations have collapsed, the species has been declared as Critically Endangered in the IUCN Red List of threatened species. In an effort to track the progress of the MME and provide updated information on the status of the species in the Greek seas, we compiled data collected through dedicated surveys and opportunistic assessments during 2019 and 2020. A total of 14589 fan mussel individuals, of which 81.1% dead, were recorded in 258 site surveys. Of the remaining 2762 live individuals, 256 were juveniles. Two marine areas which still sustain living populations were identified, namely Kalloni Gulf (Lesvos Island), and Laganas Bay (Zakynthos Island). The inner part of Kalloni Gulf appears to maintain the largest surviving population of the species in the eastern Mediterranean, with an abundance estimate of 684000 individuals (95% confi...
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(Pauly et al., 2000). The estimation of trophic level al-lows the development of new approaches to the ana-lysis of marine food webs and thereby it is essential for the management of fisheries resources as well as for quantifying the... more
(Pauly et al., 2000). The estimation of trophic level al-lows the development of new approaches to the ana-lysis of marine food webs and thereby it is essential for the management of fisheries resources as well as for quantifying the effects of fishing on the ecosystem (Pauly et al., ...
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(Pauly et al., 2000). The estimation of trophic level al-lows the development of new approaches to the ana-lysis of marine food webs and thereby it is essential for the management of fisheries resources as well as for quantifying the... more
(Pauly et al., 2000). The estimation of trophic level al-lows the development of new approaches to the ana-lysis of marine food webs and thereby it is essential for the management of fisheries resources as well as for quantifying the effects of fishing on the ecosystem (Pauly et al., ...
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Length-weight (L-W) relationships were estimated and compared for 10 commercially important fish species caught during September-December 2004 from two lagoons in the Ionian Sea based on similar length ranges. The median value of the... more
Length-weight (L-W) relationships were estimated and compared for 10 commercially important
fish species caught during September-December 2004 from two lagoons in the Ionian Sea based on
similar length ranges. The median value of the exponent b of the L-W relationships was 3.091 and
ranged from 2.444 to 3.536. The larger specimens of the mid-trophic level species (i.e. Sparus aurata,
Diplodus annularis and D. sargus) were heavier at the same length in the less eutrophic lagoon. In
contrast, most of the low-trophic level species (i.e. Mugilidae) did not show significant (P>0.05)
differences of the L-W parameters between the studied lagoons. The estimated parameters of the
L-W relationships for each species between the two lagoons in relation to their trophic state are also
discussed. Our findings indicated that the L-W relationships of the mid-trophic level species may be
possibly used as an index of the trophic state in lagoons.
fish species caught during September-December 2004 from two lagoons in the Ionian Sea based on
similar length ranges. The median value of the exponent b of the L-W relationships was 3.091 and
ranged from 2.444 to 3.536. The larger specimens of the mid-trophic level species (i.e. Sparus aurata,
Diplodus annularis and D. sargus) were heavier at the same length in the less eutrophic lagoon. In
contrast, most of the low-trophic level species (i.e. Mugilidae) did not show significant (P>0.05)
differences of the L-W parameters between the studied lagoons. The estimated parameters of the
L-W relationships for each species between the two lagoons in relation to their trophic state are also
discussed. Our findings indicated that the L-W relationships of the mid-trophic level species may be
possibly used as an index of the trophic state in lagoons.
Zooplankton and hydrography of the upper 200 m was studied in coastal and pelagic waters o¡ central Greece (eastern Mediterranean) during July 1998. The spatial distribution of the main environmental (temperature, salinity, £uorescence)... more
Zooplankton and hydrography of the upper 200 m was studied in coastal and pelagic waters o¡ central Greece (eastern Mediterranean) during July 1998. The spatial distribution of the main environmental (temperature, salinity, £uorescence) and zooplankton (abundance, dry-...
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We developed a simple and inexpensive digital image analysis method for measuring leaf area and the length of strapped-shaped seagrass leaves. The method uses specialized software that permits automatic leaf and scale recognition in... more
We developed a simple and inexpensive digital image analysis method for measuring leaf area and the length of strapped-shaped seagrass leaves. The method uses specialized software that permits automatic leaf and scale recognition in digital images along with batch image processing. The leaf biometrics of 80 Posidonia oceanica and Cymodocea nodosa leaves were used for the evaluation of the method for accuracy, precision, and speed in comparison to manual measurements. Each leaf was measured 90 times under different combinations of several factors that might affect software estimation. The factors examined included leaf shape, leaf orientation in the image, scale dimensions, image resize, and binary conversion. Estimates of leaf length and leaf area were highly correlated between the new image analysis procedure and manual measurements. Relative error values between the two methods were <10% in 99% of leaf length measures and in 75% of leaf area measures. The factors examined explained <10% of the relative error variance; the remaining variance was mostly attributed to technical issues concerning leaf size and image illumination. The digital method proved to be approximately 2.5 times faster than the manual one.
Coralline algae are one of the most important constructors of biogenic habitats. In the Mediterranean Sea, the dominant coralline algae species form crusts comprising formations known as coralligène, considered as very important fishing... more
Coralline algae are one of the most important constructors of biogenic habitats. In the Mediterranean Sea, the dominant coralline algae species form crusts comprising formations known as coralligène, considered as very important fishing grounds by fishermen. Due to the ...