Niki Milatou

Direct Ageing and Growth using Dorsal Fin Spines of Bluefin Tuna Thunnus thynnus (Scombridae) Reared in Sea Cages and a Comparison with Wild Populations

Journal of Ichthyology, Mar 30, 2023

Ecosystem-Based Blue Growth: The Case of the Semi-Enclosed Embayment of the Inner NE Ionian Sea and Adjacent Gulfs

Water

Ecosystem-based Blue Growth reflects the need to develop human activities taking place in the mar... more Ecosystem-based Blue Growth reflects the need to develop human activities taking place in the marine environment, under the scope of protecting marine ecosystems. To this end, the Marine Strategy Framework Directive identifies the specific ecological characteristics of a marine area, the human activities taking place in it and the main pressures induced thereof. The present work focuses on the semi-enclosed embayment of the Inner Ionian and adjacent gulfs (the Gulf of Corinth and the Gulf of Patras) in Western Greece, in order to present the type of environmental data and information required to be considered in the framework of ecosystem-based Blue Growth. Such data may include oceanographic and physical environmental features, biological and ecological distributions, areas of importance for species, communities, and habitats, along with spatial and temporal information regarding human activities and pressures caused. Data interpretation shows that future economic development in th...

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Creating the base for MSP; depicting the environmental status of Inner Ionian-Korinthiakos Gulf

Global NEST International Conference on Environmental Science & Technology

Marine Spatial Planning (MSP) reflects the need to plan and regulate all human uses taking place ... more Marine Spatial Planning (MSP) reflects the need to plan and regulate all human uses taking place in the marine environment, under the scope of protecting marine ecosystems. MSP requires the identification of the specific ecological characteristics of the marine area to be managed, as well as the human uses taking place and the main pressures and impacts induced. The present work focused on Inner Ionian-Korinthiakos Gulf, situated in Western Greece, defining the status of the coastal and marine environment of the area in the framework of MSP. Existing information was collected, gathered in a geodatabase and mapped; biological and ecological distributions, areas of importance for particular species, communities or habitats; oceanographic and other physical environmental features (bathymetry, currents, sediments, seismicity), spatial and temporal information regarding human activities and pressures caused. The data collected was related to MSFD characteristics and pressures, based on D...

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Trace metal accumulation in Atlantic bluefin tuna and correlations with protein-lipid composition

Food Chemistry

MSFD In-Depth Knowledge of the Marine Environment as the Stepping Stone to Perform Marine Spatial Planning in Greece

by Katerina Karditsa, M. Dassenakis, Stelios Petrakis, Niki Milatou, and Theodora Paramana

Water, 2021

The multiple anthropogenic activities taking place in the marine environment increase and create ... more The multiple anthropogenic activities taking place in the marine environment increase and create a high demand for maritime space. The pressures generated thereof on coastal and marine resources require an integrated planning and management approach. The MSPD (2014/89/EU) forms the legislative framework to regulate maritime activities and ensure a sustainable use of the marine environment. Based on the MSFD (2008/56/EC), the present study provides an overview of the state of the marine environment in Greece and the existing pressures while examining the potential contribution of MSFD knowledge to the MSPD implementation, identifying possible knowledge gaps for the subsequent MSP process phases. It is supported that the MSFD constitutes the best available scientific knowledge about the ecosystem and its dynamics, and provides an open access database which should be optimally used in the MSP process. The MSFD data provided concerning Greece can support the implementation of the MSP pr...

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The Hellenic Marine Observing, Forecasting and Technology System—An Integrated Infrastructure for Marine Research

Journal of Marine Science and Engineering

Research infrastructures have been established throughout Europe in order to create robust organi... more Research infrastructures have been established throughout Europe in order to create robust organizations that will facilitate and enhance research and innovation processes and will advance society with innovative products and services. The Hellenic Integrated Marine Observing, Forecasting and Technology System (component of HIMIOFoTS RI) has been implemented in the framework of the National Roadmap for Research Infrastructures to form a large-scale infrastructure for the marine environment in Greece. It links together ocean observing and forecasting systems, coastal zone monitoring and management practices, as well as ocean engineering testing facilities. The overarching framework of the system supports the coordination of five organizations with expertise in the field of marine science and technology, the central management of research activities, and the common development of services and products. It comprises facilities and resources while it provides open access to research com...

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Mercury concentrations in reared Atlantic bluefin tuna and risk assessment for the consumers: To eat or not to eat?

Food chemistry, 2020

This study determines the levels of total mercury in muscle tissue from 268 reared Atlantic bluef... more This study determines the levels of total mercury in muscle tissue from 268 reared Atlantic bluefin tuna in the Mediterranean Sea, detects variations on mercury concentrations in relation to biological parameters and rearing period and evaluates the health risk posed by fish consumption taking into consideration the size, age and rearing period. A total of 30 pooled samples were analyzed. The total Hg concentrations ranged from 0.49 to 1.60 mg/kg w.w. and showed a significant positive relationship with the size and age. It was found that the longer the rearing period, the lower the mercury concentration. The total Hg exceeded the maximum level defined by the European Commission Decision in a proportion of 40.0%. Since the value of Target Hazard Quotient was higher than 1 in all different groups (medium, large, 6 months and 18 months reared specimens), the maximum possible safe weekly consumption (400 g) is suggested.

MSFD In-Depth Knowledge of the Marine Environment as the Stepping Stone to Perform Marine Spatial Planning in Greece

Water, 2021

The multiple anthropogenic activities taking place in the marine environment increase and create ... more The multiple anthropogenic activities taking place in the marine environment increase and create a high demand for maritime space. The pressures generated thereof on coastal and marine resources require an integrated planning and management approach. The MSPD (2014/89/EU) forms the legislative framework to regulate maritime activities and ensure a sustainable use of the marine environment. Based on the MSFD (2008/56/EC), the present study provides an overview of the state of the marine environment in Greece and the existing pressures while examining the potential contribution of MSFD knowledge to the MSPD implementation, identifying possible knowledge gaps for the subsequent MSP process phases. It is supported that the MSFD constitutes the best available scientific knowledge about the ecosystem and its dynamics, and provides an open access database which should be optimally used in the MSP process. The MSFD data provided concerning Greece can support the implementation of the MSP pr...

Do fattening process and biological parameters affect the accumulation of metals in Atlantic bluefin tuna?

Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, Jan 23, 2015

The objective of this study was to determine the current levels of heavy metals and trace element... more The objective of this study was to determine the current levels of heavy metals and trace elements in Atlantic bluefin tuna muscle tissues and how they are influenced by the fattening process and various life history parameters, to ascertain whether the concentrations in muscle tissue exceed the maximum levels defined by the European Commission Decision and to evaluate the health risk posed by fish consumption. A total of 20 bluefin tuna reared in sea cages, ranging from 160 to 295 cm in length and from 80 to 540 kg in weight, were sampled from a Bluefin Tuna farm, in the Ionian Sea. The condition factor K of each specimen was calculated and their age was estimated. Heavy metal and trace element (Hg, Zn, Fe and Cu) content were determined in muscle tissue using Cold Vapour Atomic Absorption Spectrometry and Flame and Graphite Furnace Atomic Absorption Spectrometry. The total mercury concentrations ranged from 0.28 to 1.28 mg/kg w.w., zinc from 5.81 to 76.37 mg/kg w.w., iron from 12....

Age structure and growth of bluefin tuna (Thunnus thynnus, L.) in the capture-based aquaculture in the Mediterranean Sea

Aquaculture, 2014

The principal objective of this study was to estimate the age and growth, length-weight relations... more The principal objective of this study was to estimate the age and growth, length-weight relationships and condition factors of the Mediterranean bluefin tuna (Thunnus thynnus) in a capture-based aquaculture farm and to reveal possible differences among farmed (reared in sea cages for 18 months), fattened (reared in sea cages for 6-7 months) and wild specimens. Moreover, to determine the age composition of the fish destined for fattening and farming operations with the current lack of demographic information makes the bluefin tuna stock assessment extremely difficult. For this purpose, a total number of 2096 specimens (ranging from 102 to 295 cm in fork length and from 33 to 540 kg in round weight) were sampled, from the Greek Bluefin Tuna Farm (GR 01/2004), in the Ionian Sea (38°26′ 0.07 N, 21°1′ 48.85 E), during the five year period 2007-2011. In addition, length and weight literature data from wild specimens captured in the central Mediterranean Sea were analyzed. The results revealed high percentage difference in weight between wild and reared in sea cages bluefin tuna of the same fork length, which reached a maximum of 43.9% in large specimens. The condition factor of the reared in sea cages bluefin tuna ranged from 1.24 to 3.16 with a mean value of 2.04 ± 0.19. The mean condition factor of the farmed specimens (1.92 ± 0.17) was lower than that of the fattened specimens (2.08 ± 0.15). This difference was consistent both in younger and older specimens in the sample. Estimated ages that were obtained using the caudal vertebrae of 619 reared in sea cages specimens ranged from 5 to 18 years. It was observed that the age of fish has a significant impact on the condition factor. The comparison among the mean condition factor values of each age class revealed that older fish (10-20 years old) present higher values than younger ones (5-9 years old). With a view to estimating the precision of the aging method, the Average Percent Error (APE) and the Coefficient of Variation (CV) were calculated (APE = 1.89% and CV = 2.46%). The von Bertalanffy growth model was fitted to mean lengths at estimated ages and the growth parameters were determined (L ∞ = 360.3 cm, k = 0.083 yr −1 , t 0 = −0.942 yr).

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Age structure and growth of bluefin tuna (Thunnus thynnus, L.) in the capture-based aquaculture in the Mediterranean Sea

Aquaculture, 2014

The principal objective of this study was to estimate the age and growth, length-weight relations... more The principal objective of this study was to estimate the age and growth, length-weight relationships and condition factors of the Mediterranean bluefin tuna (Thunnus thynnus) in a capture-based aquaculture farm and to reveal possible differences among farmed (reared in sea cages for 18 months), fattened (reared in sea cages for 6-7 months) and wild specimens. Moreover, to determine the age composition of the fish destined for fattening and farming operations with the current lack of demographic information makes the bluefin tuna stock assessment extremely difficult. For this purpose, a total number of 2096 specimens (ranging from 102 to 295 cm in fork length and from 33 to 540 kg in round weight) were sampled, from the Greek Bluefin Tuna Farm (GR 01/2004), in the Ionian Sea (38°26′ 0.07 N, 21°1′ 48.85 E), during the five year period 2007-2011. In addition, length and weight literature data from wild specimens captured in the central Mediterranean Sea were analyzed. The results revealed high percentage difference in weight between wild and reared in sea cages bluefin tuna of the same fork length, which reached a maximum of 43.9% in large specimens. The condition factor of the reared in sea cages bluefin tuna ranged from 1.24 to 3.16 with a mean value of 2.04 ± 0.19. The mean condition factor of the farmed specimens (1.92 ± 0.17) was lower than that of the fattened specimens (2.08 ± 0.15). This difference was consistent both in younger and older specimens in the sample. Estimated ages that were obtained using the caudal vertebrae of 619 reared in sea cages specimens ranged from 5 to 18 years. It was observed that the age of fish has a significant impact on the condition factor. The comparison among the mean condition factor values of each age class revealed that older fish (10-20 years old) present higher values than younger ones (5-9 years old). With a view to estimating the precision of the aging method, the Average Percent Error (APE) and the Coefficient of Variation (CV) were calculated (APE = 1.89% and CV = 2.46%). The von Bertalanffy growth model was fitted to mean lengths at estimated ages and the growth parameters were determined (L ∞ = 360.3 cm, k = 0.083 yr −1 , t 0 = −0.942 yr).

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Click for updates Do fattening process and biological parameters affect the accumulation of metals in Atlantic bluefin tuna

The objective of this study was to determine the current levels of heavy metals and trace element... more The objective of this study was to determine the current levels of heavy metals and trace elements in Atlantic bluefin tuna muscle tissues and how they are influenced by the fattening process and various life history parameters to ascertain whether the concentrations in muscle tissue exceed the maximum levels defined by the European Commission Decision and to evaluate the health risk posed by fish consumption. A total of 20 bluefin tuna reared in sea cages, ranging from 160 to 295 cm in length and from 80 to 540 kg in weight, were sampled from a bluefin tuna farm in the Ionian Sea. The condition factor K of each specimen was calculated and their age was estimated. Heavy metal and trace element (Hg, Zn, Fe and Cu) contents were determined in muscle tissue using cold vapour atomic absorption spectrometry and flame and graphite furnace atomic absorption spectrometry. The total Hg concentrations ranged from 0.28 to 1.28 mg kg -1 w/w, Zn from 5.81 to 76.37 mg kg -1 w/w, Fe from 12.14 to 39.58 mg kg -1 w/w, and Cu from 0.36 to 0.94 mg kg -1 w/w. Only 5% of the muscle samples of tuna contained Hg above the maximum level laid down by the European Commission Decision. Moreover, 15% of the muscle samples contained Zn above the maximum level, while Fe and Cu concentrations were within the acceptable tolerable guideline values. The reared bluefin tuna had lower concentrations of Hg than the wild ones from the Mediterranean Sea. Hg and Fe concentrations showed a positive relationship with size and age of bluefin tuna, whereas negative relationships were found for the concentrations of Zn and Cu. The estimated dietary intake values of the analysed metals were mostly below the derived guidelines.

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Age structure and growth of bluefin tuna (Thunnus thynnus, L.) in the capture-based aquaculture in the Mediterranean Sea

by Persefoni Megalofonou and Niki Milatou

The principal objective of this study was to estimate the age and growth, length-weight relations... more The principal objective of this study was to estimate the age and growth, length-weight relationships and condition factors of the Mediterranean bluefin tuna (Thunnus thynnus) in a capture-based aquaculture farm and to reveal possible differences among farmed (reared in sea cages for 18 months), fattened (reared in sea cages for 6-7 months) and wild specimens. Moreover, to determine the age composition of the fish destined for fattening and farming operations with the current lack of demographic information makes the bluefin tuna stock assessment extremely difficult. For this purpose, a total number of 2096 specimens (ranging from 102 to 295 cm in fork length and from 33 to 540 kg in round weight) were sampled, from the Greek Bluefin Tuna Farm (GR 01/2004), in the Ionian Sea (38°26′ 0.07 N, 21°1′ 48.85 E), during the five year period 2007-2011. In addition, length and weight literature data from wild specimens captured in the central Mediterranean Sea were analyzed. The results revealed high percentage difference in weight between wild and reared in sea cages bluefin tuna of the same fork length, which reached a maximum of 43.9% in large specimens. The condition factor of the reared in sea cages bluefin tuna ranged from 1.24 to 3.16 with a mean value of 2.04 ± 0.19. The mean condition factor of the farmed specimens (1.92 ± 0.17) was lower than that of the fattened specimens (2.08 ± 0.15). This difference was consistent both in younger and older specimens in the sample. Estimated ages that were obtained using the caudal vertebrae of 619 reared in sea cages specimens ranged from 5 to 18 years. It was observed that the age of fish has a significant impact on the condition factor. The comparison among the mean condition factor values of each age class revealed that older fish (10-20 years old) present higher values than younger ones (5-9 years old). With a view to estimating the precision of the aging method, the Average Percent Error (APE) and the Coefficient of Variation (CV) were calculated (APE = 1.89% and CV = 2.46%). The von Bertalanffy growth model was fitted to mean lengths at estimated ages and the growth parameters were determined (L ∞ = 360.3 cm, k = 0.083 yr −1 , t 0 = −0.942 yr).

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