Irene Mantzouni’s research while affiliated with Fisheries Research Institute, Kavala and other places

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Publications (7)


Figure 1. Food-web structure in Lake Trichonis 2019. Circle size proportionally represents the biomass of each functional group and lines indicate the trophic links between functional groups. Color of the lines illustrate the magnitude of the flow rates. Numbers on the left side indicate the trophic food web levels.
Figure 3. Disentangling mortality components (other mortality caused by predation and natural mortality) and fishing mortality imposed on each functional group by different fishery types in Lake Trichonis, 2019.
Figure A1. PREBAL diagnostics [31] of the model developed for Lake Trichonida (2019). The group numbering on the xaxis is according to Table 1. Blue bars in biomass graph indicate the biomass values estimated by the model as this was not feasible from the surveys (see Materials and Methods).
Species composition (%) of the commercial, by-catch and discard ratios used in the model based on board and interview surveys conducted in professional fishing vessels in Lake Trichonis, 2019.
Ecological indicators related with community energetic and structure, cycling of nutrients and information indices, Lake Trichonis, 2019.
Assessing the Fisheries and Ecosystem Structure of the Largest Greek Lake (Lake Trichonis)
  • Article
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November 2021

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295 Reads

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4 Citations

Water

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Maria Th Stoumboudi

Abstract: An Ecopath with Ecosim (EwE) modeling approach was used to explore the ecological structure of the largest lake in Greece (Lake Trichonis). Until the mid-1990s, the lake was receiving a high level of pollution and the fishing pressure was intense, while since the early 2000s, fisheries and other human pressures gradually declined. Nowadays, the lake's fisheries mainly target Atherina boyeri due to the absence of market demand for the other fish species in the lake, resulting in a low overall fisheries pressure on the fish stocks. The model was built with data collected through: (a) field samplings, (b) in-depth targeted interviews of professional fishermen and (c) historical archive information. The model considered 22 functional groups, while fishing activities were represented by three classes according to the used gears. The outputs of the model revealed that the ecosystem is dominated by low trophic level species (also identified as keystone species), indicating the significance of bottom-up control in the regulation of food web processes. Ecological indicators depicted that the lake's ecosystem is mature and resilient to external disturbances. The methodologi-cal approach used in this study was shown to be helpful for studies addressing ecosystem structure, in particular with limited data availability.

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Approaching the "real" state of elasmobranch fisheries and trade: A case study from the Mediterranean

June 2021

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248 Reads

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28 Citations

Ocean & Coastal Management

Elasmobranchs are sensitive marine species due to their K-strategic life characteristics in combination with the intensification of fisheries. Despite the regulations and conventions protecting several species, elasmobranchs are still caught as bycatch and landed throughout the Mediterranean, a location where the pressure on shark populations is well documented. Severe knowledge gaps still exist regarding their biology, ecology and the exploitation by fisheries, due to limited research and the fact that in almost all Mediterranean countries, elasmobranchs are recorded by the national authorities in aggregated landing categories. To overcome such issues, we contrasted landings and trade of elasmobranchs using an integrative sampling in auction markets, landing sites, and fish markets at three important sites in Greece, combined with DNA analysis to address mislabeling. Five species contributed more than half of the total elasmobranch catches for all fisheries combined (62.5%); Scyliorhinus canicula (21.6%) and to a lesser extent Dasyatis sp., Mustelus mustelus, Raja radula and Dasyatis pastinaca (12.8%, 11.7%, 9.6%, and 6.9% respectively). Results highlighted that small-scale fisheries under-reported catches of threatened elasmobranchs. About 50-60% of the elasmobranch landings were threatened species while in the fish markets the corresponding contribution was reduced to 26%. Mislabeling was common throughout the year with several species sold under different names for increasing profit or to hinder their protection status. The current practices do not satisfy Common Fisheries Policy in terms of traceability, and the fishing of threatened elasmobranchs raises additional concerns as a conservation priority.


Length-girth relationships for freshwater fishes from Lake Volvi (Northern Greece)

July 2018

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240 Reads

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7 Citations

We estimated the relationships between total length (TL) and opercular (Gope) and maximum (Gmax) girths, for the seven most important freshwater fish species in Lake Volvi during 2016-2017. Both Gope and Gmax increased significant linearly with TL for all studied species with all r 2 values being greater than 0.83. When Gope and Gmax were plotted against TL for all species combined, four general length-girth relationships were identified, the slopes of which differed significantly (ANCOVA, P< 0.05) and corresponded to three general body shapes. Twenty-nine out of 52 species-season combinations showed that the intercept a and/or slope b values differed significantly among seasons, with more than half of which are attributed to the effect of spring and summer. The implications of girth measurements for selectivity estimates are also discussed.



Quantifying the implementation of Common Fisheries Policy: Patterns of fisheries violations and penalties imposed in Greek waters

April 2016

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174 Reads

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18 Citations

Marine Policy

Illegal fishing has been recognized as a global problem in achieving fisheries sustainability. In the present study, the fisheries violations and fines/penalties imposed per fishery recorded by Ministry of Mercantile Marine were analysed for the Greek waters during 1999–2013. Spatio-temporal patterns identified were related to: (a) easy access operating illegal fishery, (b) fishing effort/species abundance spatial distribution, (c) area topography, (d) local restrictions, and (e) fleet structure. Findings are crucial towards the specification of the critical zones and temporal closures for setting an efficient control system towards achieving sustainability. Improvements to the implementation of the fishing control involve the identification of high-risk areas prone to illegal fishing, the rationalisation of the fisheries legislation, the harmonization of proportionate administrative fines and the increase of transparency in the decision making process. These might increase the efficiency of the fisheries control which in turns will enhance the credibility of Common Fisheries Policy. These might control the efficiency of the fisheries which in turns will enhance the credibility of the Common Fisheries Policy.



Periodic, spatially structured matrix model for the study of anchovy (Engraulis encrasicolus) population dynamics in N Aegean Sea (E. Mediterranean)

June 2007

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141 Reads

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21 Citations

Ecological Modelling

The development of a periodic, spatially structured population matrix model for the study of North Aegean Sea anchovy population structure and dynamics is presented on the basis of its life-cycle, and the ecosystem environmental features. System heterogeneity and species life-cycle leaded to model development on seasonal scale and sub-regional basis, incorporating survival, fecundity and migration rates. Several methodological aspects concerning the periodic dynamics on a seasonal basis combined with the existence of spatial heterogeneity and age—season specific migration patterns are examined and discussed. Special attention is devoted to a possible inflow of recruits originated from Black Sea Waters, introducing a “source-sink” effect in the model and resulting in reducible projection matrices. The model also accounts for a possible outflow from the study area, structurally implemented by another virtual “sink” sub-area incorporation. A first attempt was made to calibrate the model using parameters provided by older studies and original data provided by the ANREC project focused on the anchovy—environment interactions and carried out in the area. Then the model was used to check the efficiency of various fishing limitations in space and/or time and the results confirmed the importance of the fishing activity over the spawning grounds.

Citations (5)


... It is situated within the broader context of efforts to enhance the scientific understanding of Greek inland ecosystems and implement effective management measures. Previous studies conducted in other Greek lakes such as Lake Volvi and Lake Trichonida focused on collecting fisheries-related information to shape management strategies [18,24]. However, the present research takes a significant step forward by assessing the ecological knowledge held by local fishers for potential integration into management practices. ...

Reference:

Local Ecological Knowledge (LEK) Can Guide Decision-Making in Inland Fisheries Management
Assessing the Fisheries and Ecosystem Structure of the Largest Greek Lake (Lake Trichonis)

Water

... Vol.: (0123456789) fishermen, etc. Indeed, recent studies show that illegal fishing, illegal trade, misreporting and mislabelling of elasmobranchs are still standard practices in some areas of the Mediterranean (Barbuto et al. 2010;Di Pinto et al. 2015;Giovos et al. 2020Giovos et al. , 2021Marchetti et al. 2020). However, considering that the overall status of Mediterranean elasmobranch populations worsened from 1980 to 2015, with the percentage of threatened species rising from 47 to 65% , it is plausible that the existing management regime and conservation instruments, such as the Barcelona Convention, along with the progress made in regional fisheries management measures over the last 30 years, have not been sufficient or comprehensive enough to halt overfishing and achieve the significant reduction in mortality necessary for population rebuilding (Giovos et al. 2024). ...

Approaching the "real" state of elasmobranch fisheries and trade: A case study from the Mediterranean
  • Citing Article
  • June 2021

Ocean & Coastal Management

... However, despite their importance in fishery management, very few studies have been done on LGRs worldwide. The studies at involved were reported by Santos et al. (2006) and Mendes et al. (2006) from Portugal, by Gabr and Mal (2018) from Saudi Arabia, by Daliri et al. (2012) from Iranian, by Adamidou et al. (2021), Moutopoulos et al. (2017), Stergiou and Karpouzi (2003) and Kyritsi et al. (2018) from Greece, by Jawad et al. (2015) from Syria and by Jawad et al. (2009) from Iraq. Speaking of Turkish territorial waters, the research in question are relatively new and have been carried out quite recently. ...

Length-girth relationships for freshwater fishes from Lake Volvi (Northern Greece)

... The overall annual catch in weight and value of recreational fisheries in Cyprus exceeded those of coastal commercial fisheries, highlighting the impact on local fish stocks [69]. Illegal, unreported and unregulated fishing is an activity that is engaged in by both professional and recreational fishers [70,71] and has been reported as an important threat to the sustainability of biological resources by the participating fishers of the study. The engagement of professional fishers in illegal fishing practices (including the participants) undermines conservation efforts and threatens the sustainability of biological resources and marine ecosystems [72]. ...

Quantifying the implementation of Common Fisheries Policy: Patterns of fisheries violations and penalties imposed in Greek waters
  • Citing Article
  • April 2016

Marine Policy

... Therefore, it is important to have a model that allows flexibility in the application of management actions, makes it easy to update model parameters as new information is gathered, and accounts for projection uncertainty, all of which will facilitate an adaptive management approach (Runge et al., 2013). Matrix population models can accommodate life history and management complexities, while propagating uncertainty, and informing management actions (Caswell, 2001;Mantzounia et al., 2007). Additionally, Bayesian statistical methods can be used to develop and update demographic parameter estimates under sparse data conditions. ...

Periodic, spatially structured matrix model for the study of anchovy (Engraulis encrasicolus) population dynamics in N Aegean Sea (E. Mediterranean)
  • Citing Article
  • June 2007

Ecological Modelling