Cetacean stranding and diet analyses in the North Aegean Sea (Greece)

Author(s):  
C.B. Milani ◽  
A. Vella ◽  
P. Vidoris ◽  
A. Christidis ◽  
E. Koutrakis ◽  
...  

Cetacean stranding reports in the North Aegean Sea were recorded since 1998 from Strimonikos Gulf in Chalkidiki up to Alexandroupoli on the Turkish border and in a few northern Aegean islands. On site, the specimens were examined to identify species, gender, approximate age and, when possible, cause for stranding. A total of 26 filled stomachs of five cetacean species collected since 2002 were analysed: bottlenose dolphinsTursiops truncatus(N = 8), common dolphinsDelphinus delphis(N = 8), harbour porpoisesPhocoena phocoena(N = 5), striped dolphinsStenella coeruleoalba(N = 4) and Risso's dolphinsGrampus griseus(N = 1). From the analysed stomachs it was found that the bottlenose dolphins fed mainly on snake blennyOphidion barbatum(34%), bogueBoops boops(22%) and round sardinellaSardinella aurita(13%); common dolphins on round sardinella (17%), picarelsSpicaraspp. (10%) and Cocco's lantern fishLobianchia gemellaris(9%); harbour porpoises on Gobidae (four-spotted gobyDeltentosteus quadrimaculatus41% and black gobyGobius niger37%) and round sardinella (7%); striped dolphins on Myctophydae (Madeira lantern fishCeratoscopelus maderensis51%), and on Pfeffer's enople squidAbraliopsis morisii(10%) and bogue (8%); and Risso's dolphin exclusively on Teuthidae (31%), the umbrella squidHistioteuthis bonellii(30%) and the reverse jewel squidH. reversa(14%). The present work represents the first attempt to investigate the diet up to species level for several cetaceans in Greek waters and for harbour porpoises stranded in the Mediterranean Sea.

1957 ◽  
Vol 22 ◽  
pp. 173-212 ◽  
Author(s):  
Audrey Furness

It is generally recognized that the neolithic arts, and prominent among them, the art of making pottery, spread from a Mesopotamian or Syrian centre westwards into Anatolia, the Aegean and so to the Danube: but in the present light of knowledge it is far from easy to demonstrate this process by means of comparisons of the earliest known pottery in each area. In particular the immediate origins of the Greek neolithic wares are obscure; and while they have good parallels in the Balkans, geographical considerations lead one to suppose that the Balkan cultures were derivatives of, rather than ancestral to, cultures of, for example, the North Aegean sea-board. In these circumstances, links between neolithic Macedonia and sites further east are of special interest. In this paper it is hoped to show, through a detailed comparative study of material from Samos, Kalimnos and Chios, that there existed in these East Aegean Islands a culture related to the earliest civilizations of Troy and Thermi (fig. 1), but which also exhibits parallels to Heurtley's ‘Late Neolithic’ material in Macedonia.The pottery from the lowest levels of Poliokhni in Lemnos almost certainly belongs to the series now to be described. The site, excavated throughout many seasons by the Italians, revealed three or more distinct strata beneath a level corresponding with early Troy I; but there are not many notices of it available and no illustrations or photographs. The recent publication by Brea in these Proceedings gives few details of the relevant levels.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Rachel Pool ◽  
Clara Romero-Rubira ◽  
Juan Antonio Raga ◽  
Mercedes Fernández ◽  
Francisco Javier Aznar

Abstract Background Current data about Pseudaliidae show contrasting patterns of host specificity between congeneric species. We investigated how both contact and compatibility between hosts and parasites contributed to the patterns of lungworm infection observed in a community of five species of cetaceans in the western Mediterranean. Methods The lungs of 119 striped dolphins Stenella coeruleoalba, 18 bottlenose dolphins Tursiops truncatus, 7 Risso’s dolphins Grampus griseus, 7 long-finned pilot whales Globicephala melas, and 6 common dolphins Delphinus delphis were analysed for lungworms. Parasites were identified by morphology and analysis of ITS2 sequences using both maximum likelihood and Bayesian inference methods. Body length was used as a proxy for lungworm species fitness in different hosts and compared with Kruskal-Wallis tests. Infection parameters were compared between cetacean species using Fisher’s exact tests and Kruskal-Wallis tests. Phylogenetic specificity was explored by collating the overall lungworm species prevalence values in hosts from previous surveys in various localities. To explore the relative importance of vertical and horizontal transmission, Spearman’s rank correlation was used to look for an association between host size and lungworm burden. A Mantel test was used to explore the association between lungworm species similarity and prey overlap using dietary data. Results Halocercus delphini had higher infection levels in striped dolphins and common dolphins; Stenurus ovatus had higher infection levels in bottlenose dolphins; and Stenurus globicephalae had higher infection levels in long-finned pilot whales. These results are congruent with findings on a global scale. Morphometric comparison showed that the larger nematodes were found in the same host species that had the highest parasite burden. Lungworms were found in neonatal striped dolphins and a Risso’s dolphin, and there was a weak but significant correlation between host size and parasite burden in striped dolphins and bottlenose dolphins. There was also a weak but significant association between prey overlap and lungworm species similarity. Conclusions Data indicate that phylogenetic specificity has an important role in governing host–parasite associations, as indicated by the higher infection levels and larger nematode size in certain hosts. However, diet can also influence infection patterns in these preferred hosts and contribute to less severe infections in other hosts.


Author(s):  
Ilias Lazos ◽  
Sotirios Sboras ◽  
Christos Pikridas ◽  
Spyros Pavlides ◽  
Alexandros Chatzipetros

2021 ◽  
Vol 22 (3) ◽  
pp. 653
Author(s):  
ATHANASIOS GKANASOS ◽  
EUDOXIA SCHISMENOU ◽  
KOSTAS TSIARAS ◽  
STYLIANOS SOMARAKIS ◽  
MARIANNA GIANNOULAKI ◽  
...  

We present the development of a 3D full-lifecycle, individual-based model (IBM) for anchovy and sardine, online coupled to an existing hydrodynamic/biogeochemical low-trophic level (LTL) model for the North Aegean Sea. It was built upon an existing 1D model for the same species and area, with the addition of a horizontal movement scheme. In the model, both species evolve from the embryonic stage (egg+yolk sac larva) to the larval, juvenile, and adult stages. Somatic growth is simulated with the use of a “Wisconsin” type bioenergetics model and fish populations with an adaptation of the ‘super individuals’ (SI) approach. For the reference simulation and model calibration, in terms of fish growth and population biomass, the 2000-2010 period was selected. Interannual biomass variability of anchovy was successfully represented by the model, while the simulated biomass of sardine exhibited low variability and did not satisfactorily reproduce the observed interannual variability from acoustic surveys. The spatial distribution of both species’ biomass was in relatively good agreement with field data. Additional single-species simulations revealed that species compete for food resources. Temperature sensitivity experiments showed that both species reacted negatively to a temperature increase. Anchovy, in particular, was more affected since its spawning and larval growth periods largely overlap with the period of maximum yearly temperature and low prey concentration. Finally, simulation experiments using IPCC climatic scenarios showed that the predicted temperature increase and zooplankton concentration decrease in the future will negatively affect anchovy, resulting in sardine prevalence.


1987 ◽  
Vol 24 (2) ◽  
pp. 265-278 ◽  
Author(s):  
H.E. Voultsiadou-Koukoura ◽  
A. Koukouras ◽  
A. Eleftheriou

2014 ◽  
Vol 19 (1) ◽  
pp. 273-273
Author(s):  
Athanassios Ganas ◽  
Zafeiria Roumelioti ◽  
Vassilios Karastathis ◽  
Konstantinos Chousianitis ◽  
Alexandra Moshou ◽  
...  

2017 ◽  
Vol 149 ◽  
pp. 138-150 ◽  
Author(s):  
B.-Th. Karatsolis ◽  
M.V. Triantaphyllou ◽  
M.D. Dimiza ◽  
E. Malinverno ◽  
A. Lagaria ◽  
...  

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0219671 ◽  
Author(s):  
Athanasios Gkanasos ◽  
Stylianos Somarakis ◽  
Kostas Tsiaras ◽  
Dimitrios Kleftogiannis ◽  
Marianna Giannoulaki ◽  
...  

2019 ◽  
Vol 11 (3) ◽  
pp. 680 ◽  
Author(s):  
Sofia Karampela ◽  
George Papapanos ◽  
Thanasis Kizos

The lack of understanding and definitional inconsistencies regarding agritourism and the importance of cooperation in sustaining this kind of tourism are underlined in the literature. This study analyzes the perceptions of agritourism and cooperation from actors in the sector using a plurality of methods, including unsupervised (a) text mining and (b) sentiment analysis with the use of a lexical database, as well as (c) supervised qualitative data analysis. Based on the assumption that destinations with different geographic characteristics have different features and products, two different destinations as for its accessibility and tourism recognition were selected for comparison: (a) an island—Lesvos in the North Aegean Sea, and (b) a continental mountain region—Plastiras Lake, in Greece. The data were collected from personal in-depth interviews and with the use of semi-structured questionnaires. From a methodological perspective, all three methods provided unique insights on the study’s themes, and the overall image of agritourism and cooperation was positive. A common understanding seems important for cooperation and networking; however, training is needed not only for effective promotion of agritourism, but also for cooperation techniques, benefits, trust-building mechanisms and best practices.


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