Effect of temperature on early life history in weatherfish, Misgurnus fossilis (L. 1758)

Effect of incubation temperature (range: 9–36 °C; interval: 3 °C) on artificially propagated weatherfish (Misgurnus fossilis) early ontogeny (during interval from egg fertilization to the finish of hatching) was investigated. Both, the amplitude of the incubation period (evaluated in four crucial moments), the total hatching period duration was inversely proportional to the incubation temperature and ranged from 17.5 days at 9 °C to 1.8 days at 24 °C (expressed at H50) or from 137 hours at 9 °C to 9 hours at 24 °C, respectively. There were no influence of rising temperature on the total length of newly hatched larvae (TL = 4.23–4.67 mm), in contrast to negative correlation with developmental stage (9–18 °C: stage 37; 21–24 °C: stage 36), i.e. the length might determine the age at hatching, rather than the age at hatching determines the hatching length. The thermal tolerance range in term of survival lies between 9 and 24 °C (the thermal optimum 15–24 °C, i.e. weatherfish is a warm-mesothermic species). Temperatures above 24 °C (in our study 27–36 °C) are considered the lethal temperatures already during embryonic period. It is highly recommended to distinguish an impact of suboptimal temperatures 9–12 °C on development during explored interval only, in contrast to possible other effect of these lower temperatures in context of the whole early ontogeny

Clove oil as an anaesthetic for different freshwater fish species

Abstract HAMACKOVA, J., J. KOURIL, P. KOZAK and Z. STUPKA, 2006. Clove oil as an anaesthetic for different freshwater fish species. Bulg. J. Agric. Sci., Results of experiments with clove oil utilization as an anaesthetic for fish realized in the University of South Bohemia Research Institute of Fish Culture and Hydrobiology at Vodтany are described. A series of observations was performed to evaluate the anaesthetic effects of clove oil on a broad spectrum of fish species. In selected fish species, the effect of fish size, temperature of aquatic environment, anaesthetics concentration and exposure time upon the anaesthetic effects were studied. Within the realized experiments, concentration of 0.03 -0.05 ml.l -1 can be generally recommended for fish. The only exception are salmonids and sturgeons which need lower (0.02 -0.03 ml.l -1 ) and higher (0.07 ml.l -1 ) concentrations, respectively. Exposure period between 2 and 4 min. is sufficient for full anaesthesia and is strongly dependent on water temperature

Effect of temperature on early life history in weatherfish,

Effect of incubation temperature (range: 9–36 °C; interval: 3 °C) on artificially propagated weatherfish (Misgurnus fossilis) early ontogeny (during interval from egg fertilization to the finish of hatching) was investigated. Both, the amplitude of the incubation period (evaluated in four crucial moments), the total hatching period duration was inversely proportional to the incubation temperature and ranged from 17.5 days at 9 °C to 1.8 days at 24 °C (expressed at H50) or from 137 hours at 9 °C to 9 hours at 24 °C, respectively. There were no influence of rising temperature on the total length of newly hatched larvae (TL = 4.23–4.67 mm), in contrast to negative correlation with developmental stage (9–18 °C: stage 37; 21–24 °C: stage 36), i.e. the length might determine the age at hatching, rather than the age at hatching determines the hatching length. The thermal tolerance range in term of survival lies between 9 and 24 °C (the thermal optimum 15–24 °C, i.e. weatherfish is a warm-mesothermic species). Temperatures above 24 °C (in our study 27–36 °C) are considered the lethal temperatures already during embryonic period. It is highly recommended to distinguish an impact of suboptimal temperatures 9–12 °C on development during explored interval only, in contrast to possible other effect of these lower temperatures in context of the whole early ontogeny

Current status and future perspectives of Italian finfish aquaculture

Currently available data show that shellfish and finfish production in Italy, derived both from fisheries and aquaculture activities, is on the order of 474,000 tons, each activity representing 50% of the total amount. In this context, the finfish aquaculture industry contributes on average 31 % to the national aquaculture production and on average 59 % of its value, giving a total amount of 72,000 tons and a value of around 351 million \u20ac (2010). According to FEAP statistics, Italy is the fourth largest finfish producer in EU27, after the UK, Greece, and Spain, while it is also one of the six largest finfish producers among the non-EU and EU member countries, together with Norway, UK, Greece, Turkey, and Spain. Presently, fish culture activities are mainly focused on rainbow trout (Oncorhynchus mykiss, 55.5 %), followed by European sea bass (Dicentrarchus labrax, 13.6 %), gilthead sea bream (Sparus aurata, 12.2 %), gray mullet (Mugil cephalus, 5.3 %), sturgeon (Acipenser spp., 2 %), and European eel (Anguilla anguilla, 1.7 %). Over the last 20 years, freshwater fish production and aquaculture (trout, carp, and eel) have decreased in Italy, with the exception of sturgeon. In contrast, marine fish production has significantly increased during the same period, and the two leading species, European sea bass and gilthead sea bream, presently contribute 25.8 % of the finfish production. From 1,900 tons in 1990, production reached 19,000 tons in 2010, with a 900 % increase, at an average percentage of 4.5 %. In addition, new marine fish species were successfully cultured over the same period. This review outlines the past and present situation of finfish culture in Italy and discusses future developments and priorities, with particular emphasis on new, emerging aquaculture species