Changes in quantities of water, sodium, potassium, lipid and protein were compared in developing eggs and yolk-sac larvae of herring dupes harengus L., a species with demersal eggs, and plaice Pleuroncctcs platessa L....Changes in quantities of water, sodium, potassium, lipid and protein were compared in developing eggs and yolk-sac larvae of herring dupes harengus L., a species with demersal eggs, and plaice Pleuroncctcs platessa L., a species with pelagic eggs. The principal difference between the two species was the occurrence in herring, but not in plaice of considerable increases in water content and in one or both of the above ions at three distinct stages: at fertilization,during the middle stage of egg development, and in the days immediately after hatching. Newly hatched larvae of the two species differed greatly in water content because of the difference in mass and water content of the yolk, not in the water content of the rest of the body. In herring, there were increases in sodium and potassium which coincided broadly with the increase in water content. These differences are related to the gradual acquisition of buoyancy by herring during this period, comparable with the buoyancy conferred on plaice eggs展开更多
Objective:To investigate the scales of barfin plaice(Liopsetta pinnifasciata),which depends on the size and sex of the fish.Methods:The samples were collected in Peter the Great Bay(Sea of Japan)during 2011–2014 aboa...Objective:To investigate the scales of barfin plaice(Liopsetta pinnifasciata),which depends on the size and sex of the fish.Methods:The samples were collected in Peter the Great Bay(Sea of Japan)during 2011–2014 aboard research vessels and at observation posts of Pacific Scientific Research Fisheries Center.In total,155 specimens of barfin plaice were analyzed and 2110 scales were investigated using MBS-10 binocular microscope.Results:Temporal differentiations of scale forming is revealed for barfin plaice.The eye side of its juveniles is covered mostly with cycloid scales.Ctenoid scales are observed in elder fish with the minimum size of 11.4 cm and 13.5 cm for males and females,respectively.Sexual dimorphism of the scale structure is usual for mature fish.Ctenoid scales dominate 92.8%of the males but cycloid scales dominate 85.4%of the females.Besides,74%of the males have ctenoid scales only,42%of the females have cycloid scales only,and both types of scales are presented for 38.3%of the males and 38.4%of the females on average.Conclusions:Juveniles of barfin plaice have cycloid scales only,the young immature fish,both males and females,have a small number of ctenoid scales,but ctenoid scales prevail in the adult males,while cycloid scales are still dominant for the adult females.However,many adults of both sexes have two types of scale simultaneously.The relative radius of the scales decreases with the increase of the body size.展开更多
文摘Changes in quantities of water, sodium, potassium, lipid and protein were compared in developing eggs and yolk-sac larvae of herring dupes harengus L., a species with demersal eggs, and plaice Pleuroncctcs platessa L., a species with pelagic eggs. The principal difference between the two species was the occurrence in herring, but not in plaice of considerable increases in water content and in one or both of the above ions at three distinct stages: at fertilization,during the middle stage of egg development, and in the days immediately after hatching. Newly hatched larvae of the two species differed greatly in water content because of the difference in mass and water content of the yolk, not in the water content of the rest of the body. In herring, there were increases in sodium and potassium which coincided broadly with the increase in water content. These differences are related to the gradual acquisition of buoyancy by herring during this period, comparable with the buoyancy conferred on plaice eggs
文摘Objective:To investigate the scales of barfin plaice(Liopsetta pinnifasciata),which depends on the size and sex of the fish.Methods:The samples were collected in Peter the Great Bay(Sea of Japan)during 2011–2014 aboard research vessels and at observation posts of Pacific Scientific Research Fisheries Center.In total,155 specimens of barfin plaice were analyzed and 2110 scales were investigated using MBS-10 binocular microscope.Results:Temporal differentiations of scale forming is revealed for barfin plaice.The eye side of its juveniles is covered mostly with cycloid scales.Ctenoid scales are observed in elder fish with the minimum size of 11.4 cm and 13.5 cm for males and females,respectively.Sexual dimorphism of the scale structure is usual for mature fish.Ctenoid scales dominate 92.8%of the males but cycloid scales dominate 85.4%of the females.Besides,74%of the males have ctenoid scales only,42%of the females have cycloid scales only,and both types of scales are presented for 38.3%of the males and 38.4%of the females on average.Conclusions:Juveniles of barfin plaice have cycloid scales only,the young immature fish,both males and females,have a small number of ctenoid scales,but ctenoid scales prevail in the adult males,while cycloid scales are still dominant for the adult females.However,many adults of both sexes have two types of scale simultaneously.The relative radius of the scales decreases with the increase of the body size.
