A computer-aided semen analysis system was used to assess the % motile cells following storage of carp semen in 11 different buffers at 2, 5 or 22 C. BWW and TLP were the most suitable storage buffers because carp semen stored at 5 C in these buffers following activation showed no significant decrease in % motile spermatozoa up to 24 h. But, in most of the other buffers (Fish Ringer, Cytomix, Cortland, FRT, Mannitol, FPS, NAS and TSM) the motility potential was lost by 2 h. Storage was best at pH 6-9 and at 5 C. Carp spermatozoa exhibit three distinct motility patterns, namely 'linear', 'circular' and 'haphazard', the proportion of spermatozoa with a particular motility pattern depending on storage buffer and time. All spermatozoa with a linear trajectory had high VSL, STR and LIN; those moving in circles had low VSL, STR, LIN and BCF and those with a haphazard trajectory were distinct in that they had the highest ALH and their VSL, STR, LIN and BCF were higher than the circular moving spermatozoa and lower than the spermatozoa exhibiting linear trajectory. The study also demonstrates a pronounced time-dependent decrease in VCL, VAP, VSL and ALH of carp spermatozoa following activation with water or low osmolality solutions. This study provides for the first time data related to seven motility parameters of carp spermatozoa and demonstrates how these parameter values could be used to evaluate quality of carp milt following storage in different buffers. It confirms that carp spermatozoa exhibit linear or circular trajectories and provides evidence for a third type of trajectory described as haphazard. All three motility patterns could be discriminated objectively on the seven motility parameters. 1997 The Fisheries Society of the British Isles

DNA fingerprints were obtained in three species of commercially important freshwater fishes, Labeo rohita (Hamiltonl, Catla catla (Hamilton) and Oreochromis mossambkus (Peters), using Bkm 2(8) and Ml 3 multilocus probes, Bkm 2(8) gave a higher number of bands when compared with Ml 3, However, the number of bands obtained by each probe in 0. niossainbicits was similar. The higher band-sharing coefficient obsen'ed in this species may be attributed to inbreeding as it arose from a small founder population. In L. rohita and C. catla. the Bkm 2(8) detected similar DNA fingerprints when two enzymes Hinfi and Taqi were used. The Ml 3 probe also gave similar fingerprints with three restriction enzymes (Hinl'i, Taqi, Alui), Comparison of the DNA fingerprints obtained by Bkm 2(8) and Ml 3 showed that these two probes detected different alleles. The overall similarity of the DNA fingerprint patterns in L, rohita and C. catla may be due to their genetic closeness as indicated by their satne chromosome number, C-value and their ability to produce fertile hybrids, A similar argument also holds true for the Oreocliromis species where interspecies hybridization results in fertile offspring.

Segregation of a wide range of body colour in the progenies was observed in breeding experiments with the Taiwanese red tilapias. Homozygous stocks of pink, red and golden colour morph were selected from such a stock by brother‐sister crossing for six generations. DNA fingerprinting analysis using multilocus M13 and Bkm 2(8) probe and HinfIenzyme combinations of pink individuals, showed homozygosity in their genome. Pink individuals when crossed to black Oreochromis mossambicus (Peters) resulted in all pink F1 progenies. F1 X F1 crosses resulted in segregation of pink and black in the F2 progenies in a 3 : 1 ratio. F1 pink individuals when backcrossed to O. mossambicus gave progeny in the ratio of 1: 1 of pink and black. Black individuals from the F2 generation, when crossed to O. mossambicus and pink separately, resulted in all black and all pink progenies, respectively. These results show that the pink colour is dominant over the black phenotype and is inherited as an autosomal locus with complete penetrance.

: Changes in the phosphorus-containing metabolites were monitored by 31P nuclear magnetic resonance in the developing embryos of Clarias batrachus. Phosphomonoester, yolk phosphoprotein, phosphocreatine, ATP, and inorganic phosphate (Pi) were consistently observed in all the developmental stages of C. batrachus. None of these phosphometabolites exhibited any significant change in their concentration up to the blastula stage, whereas distinct decrease in all except inorganic phosphate was observed in the fry stage. Concomitantly an increase in the concentration of inorganic phosphate was observed. Further, from the resonance positions of alpha, beta, and gamma phosphate groups of ATP, it was evident that the ATP molecules in vivo were liganded either to Ca2+ or Mg2+. This study also revealed that the intracellular pH of the developing embryos was approximately 7.05 up to the gastrula stage, after which it decreased in the fry stage to 6.98 units.

DNA fingerprints were obtained in three species of commercially important freshwater fishes, Labeo rohita (Hamilton). Catla catla (Hamilton) and Oreachromis mossambicus (Peters), using Bkm 2(8) and M13 multilocus probes. Bkm 2(8) gave a higher number of bands when compared with M13. However, the number of bands obtained by each probe in O. mossambicus was similar. The higher band‐sharing coefficient observed in this species may be attributed to inbreeding as it arose from a small founder population. In L rohita and C. catla, the Bkm 2(8) detected similar DNA fingerprints when two enzymes Hinfi and Taqi were used. The M13 probe also gave similar fingerprints with three restriction enzymes (Hinfi, Taqi, Alui). Comparison of the DNA fingerprints obtained by Bkm 2(8) and Ml 3 showed that these two probes detected different alleles. The overall similarity of the DNA fingerprint patterns in L. rohita and C. catla may be due to their genetic closeness as indicated by their same chromosome number, C‐value and their ability to produce fertile hybrids. A similar argument also holds true for the Oreochromis species where interspecies hybridization results in fertile offspring.