TY - JOUR
T1 - Gonadosomatic index in Barbus longiceps, Capoeta damascina and their natural hybrid (Pisces, Cyprinidae), versus spermatozoan index in the parental males
AU - Stoumboudi, M. Th
AU - Villwock, W.
AU - Sela, J.
AU - Abraham, M.
PY - 1993/12
Y1 - 1993/12
N2 - The yearly gonadal cycle of two Kinneret teleosts, Barbus longiceps and Capoeta damascina and of their hybrid, was assessed by measuring the gonadosomatic index (GSI) in both sexes, as well as the spermatozoan index (SPI) in the males. SPI was established through a computerized analysis system, using light microscopy images of histological preparations of the testes. Barbus longiceps specimens had highest GSI in March, 6.31 for males and 1.40 for females. Capoela damascina had highest GS1 in January, 6.63 for males and 6.88 for females. In the male‐like hybrids, the highest GSI was 5.57 in February, and in female‐like hybrids 1.83 in March; no gametes were ever formed in hybrid gonads. The highest SPI appeared in B. longiceps in April, while in C. damascina the highest SPI was found in March. In both species, the highest SPI was attained several weeks after the highest GSI was observed. It is suggested that the peak of the breeding season of both species is actually represented by the highest SPI. In males, the decreasing GSI, which corresponds to the highest SPI, represents the loss of gonad weight, which is due to the elimination of the spermatid residual bodies, prior to spermiation. In the females the decreasing GSI is the result of ovulation, and characterizes the peak of spawning activity.
AB - The yearly gonadal cycle of two Kinneret teleosts, Barbus longiceps and Capoeta damascina and of their hybrid, was assessed by measuring the gonadosomatic index (GSI) in both sexes, as well as the spermatozoan index (SPI) in the males. SPI was established through a computerized analysis system, using light microscopy images of histological preparations of the testes. Barbus longiceps specimens had highest GSI in March, 6.31 for males and 1.40 for females. Capoela damascina had highest GS1 in January, 6.63 for males and 6.88 for females. In the male‐like hybrids, the highest GSI was 5.57 in February, and in female‐like hybrids 1.83 in March; no gametes were ever formed in hybrid gonads. The highest SPI appeared in B. longiceps in April, while in C. damascina the highest SPI was found in March. In both species, the highest SPI was attained several weeks after the highest GSI was observed. It is suggested that the peak of the breeding season of both species is actually represented by the highest SPI. In males, the decreasing GSI, which corresponds to the highest SPI, represents the loss of gonad weight, which is due to the elimination of the spermatid residual bodies, prior to spermiation. In the females the decreasing GSI is the result of ovulation, and characterizes the peak of spawning activity.
KW - computerized morphometry
KW - cyprinids
KW - gonadosomatic index
KW - hybrid
KW - reproduction
UR - http://www.scopus.com/inward/record.url?scp=0011324353&partnerID=8YFLogxK
U2 - 10.1111/j.1095-8649.1993.tb01161.x
DO - 10.1111/j.1095-8649.1993.tb01161.x
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AN - SCOPUS:0011324353
SN - 0022-1112
VL - 43
SP - 865
EP - 875
JO - Journal of Fish Biology
JF - Journal of Fish Biology
IS - 6
ER -