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Risk management in the Greek mussel farming through ISO 31000

Theodorou John A., Tzovenis Ioannis

Oceanological and Hydrobiological Studies

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2024

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Vol. 53, No. 1

79--87

EN

The main risks to the sustainability of Mediterranean mussel farming in Greece were assessed using a generic framework derived from the AS/NZS ISO 31000:2009 Risk Management Model. Risk management scenarios were reviewed after they were successfully tested in the field by semi-qualitative/quantitative data generation protocols. A critical synthesis of the results identifies key indicative aspects needed by stakeholders to formulate a valid operational risk management plan for the sector.

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How do mussel provenance and spat size affect mussel aquaculture performance in the South-Western Mediterranean (Algeria)?

Belgaid Imene, Nacef Lamri, Alioua Zakia, Bachari Nour-El-Islam

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 3

239--256

EN

The objective of this research was to study the effects of size and spat origin of farmed Mytilus galloprovinciallis in mussel longlines in the east of Bou-Ismail Bay (central coastal Algeria, south-western Mediterranean). The study was conducted from October 2017 to July 2020 in the east of Bou-Ismail Bay. The mussel spat were obtained from four origin sites (Tlemcen, Tenes, Ain Tagourait and the study site) and were seeded on three spat sizes (10–30, 30–60 and >60 mm). The production performance of this species was analysed on 284 random mussel plots using average physical product (APP), gain and loss rates, condition index (CI), percentage of edibility (PE) and shell thickness index (STI). Apart from the CI and loss rate, the performance indicators showed significant differences according to spat size and source (p < 0.05). Overall, the highest APP (4.3) was recorded for the small seeded mussels (10–30) mm and for those originating from Tlemcen, near finfish cages (APP = 4.14). These individuals exhibited more efficient growth and physiology for commercial size and performed better than the spat collected at the study site. The results can be considered a valid contribution to best farming practice for optimising the production of this species in Algeria. It also contributes to the development of integrated multitrophic aquaculture (IMTA) methodology, which is suitable for use in the oligotrophic Western Mediterranean.

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Empirical approach to risk management strategies of Mediterranean mussel farmers in Greece

Theodorou John A., Tzovenis Ioannis, Katselis George

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 4

455--472

EN

Risk perception and risk responses of Greek mussel farmers are important for understanding their risk behavior and the likely success of different risk mitigation strategies. This allows policy makers and actuarial companies to decide what risk management products to offer to address specific types of risks. Results from an empirical survey showed that ex-farm prices and health/disability status of farmers are perceived as the most important sources of risk. Risk management decisions were strongly influenced by the attitudes of mussel farmers rather than their socioeconomic status or perception of risk sources. Financial reserves and an alternative source of stable income are both preferred by mussel farmers as risk management strategies, while optimizing farm management to produce at the lowest possible cost is commonly practiced to eliminate losses. Farmers recommend that for certain types of risks that lead to total losses, e.g. anoxia, tsunamis, harmful algal blooms (HABs), insurance contracts should be provided by the public sector, as in similar situations in agriculture. For other needs, customized insurance contracts should be provided by the actuarial market.

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Effects of seasonal changes and depth on growth parameters of the Mediterranean mussel (Mytilus galloprovincialis) on a shipwreck in the Eastern Mediterranean Sea

Şensurat-Genç Tuğçe, Karadal Onur, Oruç Adnan Çağlar, Özgül Aytaç, Aytaç Altan

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 4

441--454

EN

The study was conducted between July 2018 and May 2020 to compare seasonal changes in growth parameters of the Mediterranean mussel (Mytilus galloprovincialis) at different depths in two different areas of the Northeastern Mediterranean Sea (Aegean Sea). In a preliminary study, mussels were placed in cages at different depths of an artificial reef (AR – shipwreck) and natural reef (NR). Temperature, salinity, pH, and dissolved oxygen were determined seasonally at both sites at a depth of 37 m (deepwater) and 25 m (midwater). Linear increases in length and width of mussels at the AR site were recorded, while no consistent changes were observed for mussels at the NR. There was negative correlation between the specific growth rate (SGR) and salinity (r2 = 0.5098) and temperature (r2 = 0.1470) at the AR site. Negative correlations were also recorded between pH and the commercial condition index (CCI) at both the AR (r2= 0.3869) and NR (r2 = 0.3600) sites. Our findings show that depth had a significant effect (p < 0.05) on the CCI of mussels at the NR site, while its effect was insignificant for this index at the AR site (p > 0.05). This study indicates that natural reefs provide more suitable conditions for the growth of Mediterranean mussels than shipwrecks used as artificial reefs.