Systematics is traditionally based on morphological characters to both define species and establish classifications. In the past decades, partly due to the advent of molecular biology, traditional systematics has decl...Systematics is traditionally based on morphological characters to both define species and establish classifications. In the past decades, partly due to the advent of molecular biology, traditional systematics has declined while molecular systematics has tremendously increased. This results in that fewer funding are generally provided to traditional systematics, particularly for searching new morphological characters. Aquaculture, the farming of aquatic animals, has increased exponentially in the past decades, providing today more than half of fish consumed worldwide, and is expected to continue to rise. Aquaculture requires controlling the life cycle of the farmed fish in captivity, including the rearing of early life stages. Therefore, by coupling systematics and aquaculture, it could be possible to bring new funds and facilities to the former to study the early life stages of numerous fish species and to the latter it would offer a conceptual framework to perform comparative ontogeny. Together, this could help improving our knowledge on the early life stages that could be useful for both taxonomists and zootechnicians.展开更多
Domestication is a very strong process that has enabled humans to produce both plants and animals with desired traits. For land animals, this process started about 12,000 years ago and resulted in that today hundreds ...Domestication is a very strong process that has enabled humans to produce both plants and animals with desired traits. For land animals, this process started about 12,000 years ago and resulted in that today hundreds of well-defined breeds are available for the five most important farmed mammal species (cattle, pig, horse, sheep and goat). For aquatic animals, this process started much earlier, and the bulk of domestication of new species dated back only to the early 1980s. Nevertheless, there are now numerous fish species for which the life cycle is already closed in captivity and some domesticated fish have been genetically improved. This implies that what probably took hundreds of years in mammals (i.e., to control the life cycle in captivity and then to improve captive individuals) has been accomplished in only tens of years for some fish species. Based on the main problems observed today in farmed mammals, the possible consequences of this fast domestication of fish are discussed.展开更多
A host of abiotic factors modify fish social behavior. However, few studies have characterized the effects of temperature on behavior. In this study, brown trout Salmo trutta fry were reared at 5 dif- ferent temperatu...A host of abiotic factors modify fish social behavior. However, few studies have characterized the effects of temperature on behavior. In this study, brown trout Salmo trutta fry were reared at 5 dif- ferent temperatures （4℃, 6℃, 8℃, 10℃, and 12℃）. In order to characterize group structure, 3 be- havioral parameters were investigated： group social structure （based on inter-individual distances）, inter-individual relationships （based on physical contacts）, and individual activity. These behavioral parameters were studied at the emergence stage, which corresponds to a switch from a social gre- garious life in the gravel to a solitary one in the water column. Data analysis showed that the inter- individual distances increased with increasing temperature, particularly the nearest neighbor distance. The mean number of physical contacts between fry increased at both low and high tem- peratures. At high temperatures, most fry moved apart from each other after a physical contact. Swimming activity decreased at both the lower and upper temperatures （18% of activity at 4℃, 38% at 8℃, and 12% at 12℃）. This study showed that temperature modifies brown trout fry activity, inter-individual relationships, and social behavior, which all affect group cohesion before emer- gence and can influence their survival and dispersal.展开更多
文摘Systematics is traditionally based on morphological characters to both define species and establish classifications. In the past decades, partly due to the advent of molecular biology, traditional systematics has declined while molecular systematics has tremendously increased. This results in that fewer funding are generally provided to traditional systematics, particularly for searching new morphological characters. Aquaculture, the farming of aquatic animals, has increased exponentially in the past decades, providing today more than half of fish consumed worldwide, and is expected to continue to rise. Aquaculture requires controlling the life cycle of the farmed fish in captivity, including the rearing of early life stages. Therefore, by coupling systematics and aquaculture, it could be possible to bring new funds and facilities to the former to study the early life stages of numerous fish species and to the latter it would offer a conceptual framework to perform comparative ontogeny. Together, this could help improving our knowledge on the early life stages that could be useful for both taxonomists and zootechnicians.
文摘Domestication is a very strong process that has enabled humans to produce both plants and animals with desired traits. For land animals, this process started about 12,000 years ago and resulted in that today hundreds of well-defined breeds are available for the five most important farmed mammal species (cattle, pig, horse, sheep and goat). For aquatic animals, this process started much earlier, and the bulk of domestication of new species dated back only to the early 1980s. Nevertheless, there are now numerous fish species for which the life cycle is already closed in captivity and some domesticated fish have been genetically improved. This implies that what probably took hundreds of years in mammals (i.e., to control the life cycle in captivity and then to improve captive individuals) has been accomplished in only tens of years for some fish species. Based on the main problems observed today in farmed mammals, the possible consequences of this fast domestication of fish are discussed.
文摘A host of abiotic factors modify fish social behavior. However, few studies have characterized the effects of temperature on behavior. In this study, brown trout Salmo trutta fry were reared at 5 dif- ferent temperatures （4℃, 6℃, 8℃, 10℃, and 12℃）. In order to characterize group structure, 3 be- havioral parameters were investigated： group social structure （based on inter-individual distances）, inter-individual relationships （based on physical contacts）, and individual activity. These behavioral parameters were studied at the emergence stage, which corresponds to a switch from a social gre- garious life in the gravel to a solitary one in the water column. Data analysis showed that the inter- individual distances increased with increasing temperature, particularly the nearest neighbor distance. The mean number of physical contacts between fry increased at both low and high tem- peratures. At high temperatures, most fry moved apart from each other after a physical contact. Swimming activity decreased at both the lower and upper temperatures （18% of activity at 4℃, 38% at 8℃, and 12% at 12℃）. This study showed that temperature modifies brown trout fry activity, inter-individual relationships, and social behavior, which all affect group cohesion before emer- gence and can influence their survival and dispersal.
