Perch sweeper fish with scientific name Cobitis taenia is one of the Cobitidae family. Since this kind of fish lives in clean waters and in the high areas of Talar River, it can be an index on water implution. This su...Perch sweeper fish with scientific name Cobitis taenia is one of the Cobitidae family. Since this kind of fish lives in clean waters and in the high areas of Talar River, it can be an index on water implution. This survey on the diet of this specimen is done on two stations （Kaselian and Tajoon） and shallow and high areas of Talar River in Mazandaran （Southern part of Caspian sea） and the duration of this survey is from October 2008 till September 2009. We should mention that fishing was just done by electro-shocker with voltage 300 V. And this fish after fishing is fixation in 10% formalin solution. So 410 perch sweeper fish were examined and the average of relatively length of gut （RLG） was 17.35 cm. The index of vacated intestine （VI） was calculated 43.35% for all samples. From intense of diet points of view （GSI）, the most frequency of full intestines was considered in summer and spring. On the other hand, the smallness of relatively length of gut index （RLG 〈 1） shows that perch sweeper fish＇s diet manner is inclined to herbivority. In the examination of containing of digestive track, overally 10 kinds of foodstuff were known. Based on amount of this index, 2.67% Chironomidae is known as main bait in all sampling period.展开更多
Here we revise a fossil cobitid species ■Cobitis longipectoralis Zhou, 1992, based mainly on a well-preserved specimen collected recently from the taxon’s type locality of the late early Miocene of Shanwang, Shandon...Here we revise a fossil cobitid species ■Cobitis longipectoralis Zhou, 1992, based mainly on a well-preserved specimen collected recently from the taxon’s type locality of the late early Miocene of Shanwang, Shandong Province, East China. The new specimen, along with those collected by Zhou, enables us to provide an emended diagnosis and more detailed description of the species by focusing on the characters such as the structures of the suborbital spine and the presence and shape of the lamina circularis at the base of the second pectoral fin ray in adult males, the presence of a frontoparietal fontanelle, and a quad- rate-metapterygoid fenestra, etc. The long pectoral fin, initially considered by Zhou as the most important character of the spe- cies, however, turns out to be not diagnostic for the species. ■Cobitis longipectoralis Zhou, 1992 is not only the most informative and best-preserved early cobitid fossil known thus far but also the only and earliest cobitid fossil from East Asia.展开更多
Objective:To describe the age structure,growth,reproductive characteristics and lengthweight relationship of Cobitis avicennae(C.avicennae)population inhabiting the Gamasiab River,Western Iran.Methods:C.avicennae was ...Objective:To describe the age structure,growth,reproductive characteristics and lengthweight relationship of Cobitis avicennae(C.avicennae)population inhabiting the Gamasiab River,Western Iran.Methods:C.avicennae was collected throughout the spawning season(February to July,2015)in Gamasiab River and its age,growth,and reproductive traits were investigated.Total length was measured to the nearest 1 mm,and total weight and gonad weight to the nearest 0.001 g.The age was determined using operculum.Sex was determined by examination of the gonad tissue.The number of eggs was estimated by gravimetric method.Average egg diameter was examined by measuring 30 eggs for each female with an ocular micrometer microscope.Results:The maximum age was 3 years.The specimens size ranged from 32.63 to 100.00 mm in total length,weighing from 0.22 to 5.17 g in total weight.Length-weight relationship was estimated as W=1E-05TL^(2.85)for females,W=1E-05TL^(2.83)for males and W=7E-06TL^(2.94)for the population.The growth model was isometric for males and sexes combined and negatively allometric for females.The absolute fecundity ranged between 132 and 900 eggs with a mean of 490.55 eggs.Conclusions:The life history traits described for C.avicennae from the Western Iran basin indicated a moderate life span,a moderate body weight,a short duration of spawning season,relatively high heterogeneity in egg size and low egg number.Some life history traits of C.avicennae demonstrated obvious differences compared with its closely related species,indicating that latitude and local environment conditions are important selective forces for this species.展开更多
文摘Perch sweeper fish with scientific name Cobitis taenia is one of the Cobitidae family. Since this kind of fish lives in clean waters and in the high areas of Talar River, it can be an index on water implution. This survey on the diet of this specimen is done on two stations （Kaselian and Tajoon） and shallow and high areas of Talar River in Mazandaran （Southern part of Caspian sea） and the duration of this survey is from October 2008 till September 2009. We should mention that fishing was just done by electro-shocker with voltage 300 V. And this fish after fishing is fixation in 10% formalin solution. So 410 perch sweeper fish were examined and the average of relatively length of gut （RLG） was 17.35 cm. The index of vacated intestine （VI） was calculated 43.35% for all samples. From intense of diet points of view （GSI）, the most frequency of full intestines was considered in summer and spring. On the other hand, the smallness of relatively length of gut index （RLG 〈 1） shows that perch sweeper fish＇s diet manner is inclined to herbivority. In the examination of containing of digestive track, overally 10 kinds of foodstuff were known. Based on amount of this index, 2.67% Chironomidae is known as main bait in all sampling period.
基金supported by National Natural Science Foundation of China (Grant Nos. 40432003 and 40662001)State Key Laboratory of Palaeobiology and Stratigraphy (Grant No. 063106)Cypriniformes Tree of Life under the U.S. National Science Foundation to R. Mayden (Grant No. EF0431326)
文摘Here we revise a fossil cobitid species ■Cobitis longipectoralis Zhou, 1992, based mainly on a well-preserved specimen collected recently from the taxon’s type locality of the late early Miocene of Shanwang, Shandong Province, East China. The new specimen, along with those collected by Zhou, enables us to provide an emended diagnosis and more detailed description of the species by focusing on the characters such as the structures of the suborbital spine and the presence and shape of the lamina circularis at the base of the second pectoral fin ray in adult males, the presence of a frontoparietal fontanelle, and a quad- rate-metapterygoid fenestra, etc. The long pectoral fin, initially considered by Zhou as the most important character of the spe- cies, however, turns out to be not diagnostic for the species. ■Cobitis longipectoralis Zhou, 1992 is not only the most informative and best-preserved early cobitid fossil known thus far but also the only and earliest cobitid fossil from East Asia.
文摘Objective:To describe the age structure,growth,reproductive characteristics and lengthweight relationship of Cobitis avicennae(C.avicennae)population inhabiting the Gamasiab River,Western Iran.Methods:C.avicennae was collected throughout the spawning season(February to July,2015)in Gamasiab River and its age,growth,and reproductive traits were investigated.Total length was measured to the nearest 1 mm,and total weight and gonad weight to the nearest 0.001 g.The age was determined using operculum.Sex was determined by examination of the gonad tissue.The number of eggs was estimated by gravimetric method.Average egg diameter was examined by measuring 30 eggs for each female with an ocular micrometer microscope.Results:The maximum age was 3 years.The specimens size ranged from 32.63 to 100.00 mm in total length,weighing from 0.22 to 5.17 g in total weight.Length-weight relationship was estimated as W=1E-05TL^(2.85)for females,W=1E-05TL^(2.83)for males and W=7E-06TL^(2.94)for the population.The growth model was isometric for males and sexes combined and negatively allometric for females.The absolute fecundity ranged between 132 and 900 eggs with a mean of 490.55 eggs.Conclusions:The life history traits described for C.avicennae from the Western Iran basin indicated a moderate life span,a moderate body weight,a short duration of spawning season,relatively high heterogeneity in egg size and low egg number.Some life history traits of C.avicennae demonstrated obvious differences compared with its closely related species,indicating that latitude and local environment conditions are important selective forces for this species.
