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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural observations of euspermatozoa and paraspermatozoa in a copulatory cottoid fish Blepsias cirrhosus (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 64 (2004), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Euspermatozoa and paraspermatozoa of a copulatory (internal insemination with external sperm transfer) cottoid fish Blepsias cirrhosus were observed ultrastructurally. Euspermatozoa of B. cirrhosus consisted of an acrosome-less, thin, disk-like sperm head (1·6-2·0 μm in length and 1·3-1·6 μm in width), a long middle piece, and a long flagellum (c. 30 μm). Aberrant spermatids, which were rich in cytoplasm and possessed two nuclei, occurred in testicular lobules. They were also observed in semen and were round (5·0-5·3 μm in diameter) and biflagellate, suggesting that they are released along with euspermatozoa at ejaculation. The nuclei of aberrant spermatids developed into masses of highly electron-dense globules. Judging from their form, nuclear condition, and connection with normal spermatids by intercellular bridges during spermiogenesis, aberrant spermatids of B. cirrhosus are considered hyperpyrenic paraspermatozoa formed by incomplete cytokinesis at the second meiotic division.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0022-1112.2004.00407.x
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  • 2
    Electronic Resource
    Electronic Resource
    Mixed-species brooding between two Baikal sculpins: field evidence for intra- and interspecific competition for reproductive resources (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 60 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In an examination of the distribution of nesting spaces of two Baikal sculpins, Paracottus kneri and Cottus kessleri, along two transects offshore at Bolshye Koty, a total of 43 P. kneri nests, 32 C. kessleri nests and one Batrachocottus baicalensis nest was found. Males of these species established breeding nests under overhanging stones in the same manner as most freshwater sculpins, but nests of each species were clearly partitioned in separate zones. Cottus kessleri nests were found where the lake floor was mostly covered with overhanging stones. Paracottus kneri nests, however, were found where the lake floor was moderately covered with overhanging stones. Two mixed-species brooding nests with a C. kessleri guarding male were found in an area bounded by the two zones. Each of these nests comprised one P. kneri egg mass and several C. kessleri egg masses, guarded by a C. kessleri male. The nest distribution of these fishes appears to reflect intra- and interspecific competition for overhanging stones as a reproductive resource rather than interspecific difference of nest selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb02422.x
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  • 3
    Electronic Resource
    Electronic Resource
    Spawning and maternal-care behaviours of a copulating sculpin, Radulinopsis taranetzi (2005)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 67 (2005), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The fertilization mode, and spawning and egg-care behaviours of the sculpin Radulinopsis taranetzi were investigated in the laboratory. Embryonic development began only after the eggs came into contact with sea water. Females spawned c. 1000 eggs and covered them with sand using their pectoral and caudal fins. Unlike other cottids, the females guarded the egg masses after spawning. During the parental period, the supramaxillary lamina and mandibular lamina of females extended to form a disc-like structure, which was used to ‘suck’ water from near the surface of the egg mass. The frequency and duration of this ‘sucking’ behaviour increased gradually until hatching, which occurred after 23–26 days at 8° C. The oxygen consumption of the embryos was positively related to the ‘sucking’ activity. All females in this study spawned only once during the spawning season, in contrast with the paternal-care copulating cottids, which are multiple spawners.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0022-1112.2005.00728.x
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of extracellular environments on the motility of spermatozoa in several marine sculpins with internal gametic association
    Amsterdam : Elsevier
    Comparative Biochemistry and Physiology -- Part A: Physiology 106 (1993), S. 25-29 
    Details
    ISSN: 0300-9629
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0300-9629(93)90033-Z
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  • 5
    Electronic Resource
    Electronic Resource
    Microsatellite markers and multiple paternity in a paternal care fish, Hexagrammos otakii (2000)
    Springer
    Journal of ethology 18 (2000), S. 101-104 
    Details
    ISSN: 1439-5444
    Keywords: Key words Sneaking ; Counteraction ; Emission-timing ; Sperm-ammount ; Sperm competition ; Alloparental care
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fertilization success of sneaking behavior in a paternal care fish, Hexagrammos otakii, was estimated using microsatellites as genetic markers. Sneaking behavior was observed using a video camera placed near the nest of a breeding territorial male. Two egg masses fertilized by different patterns of sperm emission by the territorial male and sneaker males were examined for paternity discrimination. When a sneaker emitted a large amount of sperm after sperm emission by the territorial male, the sneaker fertilized more eggs than the territorial male. When the territorial male and a sneaker alternately emitted semen, the territorial male fertilized the most eggs. These results suggest that both the amount of emitted sperm and the timing of sperm emission are important factors in sperm competition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101640070007
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    Paper (German National Licenses)
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