Using eye lens diameter as age indicator of young Lithognathus mormyrus and Diplodus vulgaris

Eye lens diameter was analyzed in two sparid fish species, Lithognathus mormyrus and Diplodus vulgaris, in order to determine the possibility of using these data for age determination. The results showed that the technique could be adopted for determining the age of the two species when the specimens are very young. The method is especially useful for age determination when otolith or scale rings are not visible or when false rings may give erroneous readings

A bio-economic evaluation of the potential for establishing a commercial fishery on two newly developed stocks: the Ionian Red Shrimp Fishery

It has recently been shown that two deep-water red shrimp species (Aristeus antennatus and Aristaeomorpha foliacea) have the potential to support a viable fishery in the Greek Ionian Sea (eastern Mediterranean). In this article, we investigate (i) the evolution that this newly developed trawl shrimp fishery may undergo when subjected to different management measures, and (ii) the most suitable extraction rates considering the uncertainties about the resource. We further analyse the effects that potential future fuel price increases and changes in the market may have on the fishery. Forecasting the biological and economic consequences of management actions, as well as the effects of market changes on inputs and outputs before they are applied, may help managers select the most suitable management options. We approach the problem by means of bio-economic simulation analysis. The results of this study show that fishing effort can increase by 50-100%, increasing the fleet's profitability without jeopardizing the sustainability of the fishery

Empowering Leadership and Employee Motivation, Behaviors, and Well-Being: Enabling or Burdening?

Empowering leadership has shown to be related to a variety of positive organizational outcomes, as well as positive individual outcomes for employees. However, some evidence suggests that there is also a burdening side to empowering leadership, whereby the increased autonomy and responsibility provided to employees can in fact be detrimental to firm and employee performance. The purpose of this study was to examine the effects of both enabling and burdening empowering leadership on employee motivation, extra-role behaviors, and well-being, while taking into account individual differences such as employee general self-efficacy and proactive personality. Drawing on the self-determination theory and social cognitive theory, this study proposes that empowering leadership will lead to positive behaviors, and reduced emotional exhaustion and turnover intention, through autonomous motivation, and that personality traits in subordinates will moderate these relationships. The data was collected using a short online questionnaire using employees (n = 267) from various firms across North America. Empowering leadership was positively related to autonomous motivation, and was also positively related to extra-role behavior, and negatively related to emotional exhaustion and turnover intention. Results showed support for the moderating effects of self-efficacy and proactive personality on extra-role behavior, emotional exhaustion and turnover intention. The findings of this study are relevant for the workforce, as leaders who are more aware of the effects of their leadership style will be better able to adjust their behavior accordingly in order to ensure their employees are performing at an optimal level, which will result in a more motivated and engaged workforce, and ultimately increased overall firm effectivenes

Preliminary biological data on Pomadasys incisus (Osteichthyes: Haemulidae) in the Aegean Sea, Greece

The present paper gives, for the first time, some biological data concerning Pomadasys incisus in theArgolikos Gulf (C. Aegean Sea). The bastard grunt (Pomadasys incisus) is a thermophilic species welladapted in the above area, but the status of fishery suggests an overexploitation. The sex ratio was infavour of males. The length frequency distribution did not differ between the sexes. Growth in weight wasestimated by means of the length-weight relationship. Reproduction seemed to take place in summer. Certainmorphometric characters appeared to be useful while comparing populations among the differentpopulations in the Mediterranean

Preliminary biological data on Pomadasys incisus (Osteichthyes: Haemulidae) in the Aegean Sea, Greece

The present paper gives, for the first time, some biological data concerning Pomadasys incisus in theArgolikos Gulf (C. Aegean Sea). The bastard grunt (Pomadasys incisus) is a thermophilic species welladapted in the above area, but the status of fishery suggests an overexploitation. The sex ratio was infavour of males. The length frequency distribution did not differ between the sexes. Growth in weight wasestimated by means of the length-weight relationship. Reproduction seemed to take place in summer. Certainmorphometric characters appeared to be useful while comparing populations among the differentpopulations in the Mediterranean

Studies on the allometric growth of the caramote prawn Melicertus kerathurus (Decapoda, Penaeidae) in Western Greece (E. Mediterranean)

The relative growth of eleven body parts (carapace length, height, width, abdominal length, height and width, rostral length and telson length) of males and females of the caramote prawn Melicertus kerathurus was studied in samples from the Amvrakikos Gulf (Western Greece, E. Mediterranean). In addition to this, the relative growth of the length and the maximum width – and consequently the surface - of the appendix masculina of males was also studied. In general, both sexes showed similar patterns of relative growth. However, the females’ body appendages were significantly greater than those of the males. A negative allometry of escaping appendages (telson), abdomen (related to the metabolic processes, rapid locomotion and reproduction), rostrum, appendix masculina (related to mating and sperm transfer) and carapace height and width was found in both sexes. The biometric studies in this species in the central and western Mediterranean are in agreement with those from the eastern part of the basin, suggesting that all the populations throughout the Mediterranean could be considered as uniform

Studies on the allometric growth of the caramote prawn Melicertus kerathurus (Decapoda, Penaeidae) in Western Greece (E. Mediterranean)

The relative growth of eleven body parts (carapace length, height, width, abdominal length, height and width, rostral length and telson length) of males and females of the caramote prawn Melicertus kerathurus was studied in samples from the Amvrakikos Gulf (Western Greece, E. Mediterranean). In addition to this, the relative growth of the length and the maximum width – and consequently the surface - of the appendix masculina of males was also studied. In general, both sexes showed similar patterns of relative growth. However, the females’ body appendages were significantly greater than those of the males. A negative allometry of escaping appendages (telson), abdomen (related to the metabolic processes, rapid locomotion and reproduction), rostrum, appendix masculina (related to mating and sperm transfer) and carapace height and width was found in both sexes. The biometric studies in this species in the central and western Mediterranean are in agreement with those from the eastern part of the basin, suggesting that all the populations throughout the Mediterranean could be considered as uniform

Autohtoni nasadi mekušaca: strategijsko upravljanje, zaštita, obnavljanje i eksploatacija

It is no secret that commercially important oyster beds are declining or fluctuating sharply all over the world. In Chesapeake Bay (USA) from 1985-1990 there was a sharp decline in production from 700,000 - 800,000 kg to 4,000 - 5,000 kg. In Australia production has declined since World War II to 45% of earlier levels. The same has occurred in the Mediterranean: according to F.A.O. (1997) European oyster stocks increased from 1950-1990, but by 1995-2000 they had declined almost linearly to about one-half earlier amounts. In addition, other Molluscs are considered to represent “concave downward” declining stocks (F.A.O., 1997). The main producing countries in the East Mediterranean for the European flat oyster are Italy (46.1%), Greece (4.4%), Turkey (2.2%), and Croatia (1.5%). For other species, the main producing countries are Italy (69.0%), Greece (16.0%), Turkey (2.2%), and Croatia (3.7%). The Adriatic, with considerable river input and a high degree of eutrophication, is important for mollusc production. The main question, however, is how stable and sensitive this industry is. Starting from the main issue that the natural stocks decline the need for the elaboration of a strategic management plan for the native mollusc beds is imperative. Strategic planning is an important tool for any sector when we need to do more than react to events as they unfold. Strategic planning involves a realistic assessment of the external environment and the factors bearing on it, now and in the future. Arising from this analysis, various “strategies” can be determined which will enable overall objectives to be met. The framework of a strategic management plan includes discussion and measures on issues such as property rights, policy issues affecting water quality and quality assurance, other aspects of government administration, generic promotion and R&D. Issues affecting business structure, the specific production technology employed, brand development and related aspects of marketing, are more likely to reflect the goals of individual businesses, although there may be a role for voluntary collective action (but not mandatory, or industry-wide action) in some circumstances. Strategic planning for the development of mollusc industry is not strictly a scientific or a administration problem to solve. It is a multi-parametric and multi-sectoral problem and as in any similar case, our inability to handle multi-parametric problems results to plans with limited results or more frequently, to disasters.Općenito je poznato da su nasadi kamenica posvuda u svijetu izloženi većim oscilacijama ili su u opadanju. U SAD-u, Chesapeake Bay, u razdoblju od 1985. do 1990. zabilježeno je znatno opadanje u proizvodnji sa 700 - 800.000 kg godišnje na 4.000 - 5.000 kg godišnje. U Australiji proizvodnja je u padu od Drugog svjetskog rata, i iznosi 45%. Slično je i na Mediteranu: prema godišnjaku FAO (1997.) europski stokovi kamenica pokazivali su rast u razdoblju 1950.-1990., nakon toga opadanje je linearnog oblika pa od 1995. do 2000. iznosi 45-50%. Što se tiče proizvodnje ostalih pripadnika skupine školjkaša, smatra se da su stokovi u opadanju te prate “konkavno silazeću” putanju (FAO, 1997.). Glavni proizvođači europske plosnate kamenice na istočnom Mediteranu su: Italija (46,1%), Grčka (4,4%), Turska (2,2%) i Hrvatska (1,5%). Glavne zemlje proizvođači skupine mekušaca su: Italija (69,0%), Grčka (16,0%), Turska (2,2%) i Hrvatska (3,7%). Površina Jadranskog mora, sa značajnim dotokom slatke vode i visokim stupnjem eutrofikacije, bitno je područje za proizvodnju mekušaca. Ključno je pitanje pritom koliko je ova industrija osjetljiva i stabilna