THE BEHAVIOUR AND PHYSIOLOGY OF HERRING AND OTHER CLUPEIDS 267
C. ViabiZity of the gam&es and artifxiab storage
Herring sperm remains fertile for at least 3 hr in sea water at 8°C
(Blaxter, unpublished). Yanagimachi (1953) found that the sperm of
Clupea p a l h i i remained fertile to a limited extent after 12 hr in sea
water at 8-10°C. I n Ringer solution or in Iower salinities some fertility
was retained after 24 hr. However, Stroganov (1938) showed that the
sperm of Caspialosa volgensis lived for 1 min or less in fresh water and
that sperm from mixed males survived less well than sperm from one
male ; of the eggs 60% could still be fertilized after about 30 hr.
Gamete storage has been developed mainly in salmonids as a piscicultural technique. In herring, short-term storage haa been used
(Blaxter, 1955) for transporting gametes from where the parents are
caught to the laboratory for controlled rearing studies, and long-term
storage for making cross fertilizations between herring races spawning
at different seasons. For short-term storage, different diluents such aa
phosphate and borate buffers with and without chicken egg yolk were
used, but the most satisfactory results were obtained by storing whole
gonads dry at about 4°C. While fertilization of eggs may be obtained
even after 6 to 7 days of dry storage, a high hatching rate is only to be
expected after periods not exceeding 36 hr storage. Long-term storage
has been achieved successfully with sperm, but not with eggs, by
freezing in glycerol and diluted sea water to a temperature of -79°C.
At least 6 months later the sperm were viable and crosses were made
between spring and autumn spawning herring (Blaxter, 1957) and
between different races of spring spawners (Blaxter and Hempel, 1961).
Storage of gametes within the dead parent’s body does not seem to
be successful and the fertilization rate was very low after I8 hr in
herring. Stroganov (1938) found in Cuqklosa voZgemia that the sperm
started to die 10-60 min after the death of the parent, if the testis wm
left in situ.
D. Fertilization
Fertilization in Clupea pallaaii was described by Yamamoto (1958)
as being normally monospermic. He showed that immediately following
sperm entry the fertilization membrane, which was a protein structure,
withdrew from the chorion thus forming a perivitelline space. Into this
space are extruded the droplets of the cortical alveoli (Volodin, 1956).
Yanagimachi and Kanoh (1953) found that the calcium ion concentration was critical for successful sperm entry. Yanagimachi (1957)
described a factor bound to the egg membranes of C l u p p a W i that
caused quiescent sperm to become active if brought near it. This
C. ViabiZity of the gam&es and artifxiab storage
Herring sperm remains fertile for at least 3 hr in sea water at 8°C
(Blaxter, unpublished). Yanagimachi (1953) found that the sperm of
Clupea p a l h i i remained fertile to a limited extent after 12 hr in sea
water at 8-10°C. I n Ringer solution or in Iower salinities some fertility
was retained after 24 hr. However, Stroganov (1938) showed that the
sperm of Caspialosa volgensis lived for 1 min or less in fresh water and
that sperm from mixed males survived less well than sperm from one
male ; of the eggs 60% could still be fertilized after about 30 hr.
Gamete storage has been developed mainly in salmonids as a piscicultural technique. In herring, short-term storage haa been used
(Blaxter, 1955) for transporting gametes from where the parents are
caught to the laboratory for controlled rearing studies, and long-term
storage for making cross fertilizations between herring races spawning
at different seasons. For short-term storage, different diluents such aa
phosphate and borate buffers with and without chicken egg yolk were
used, but the most satisfactory results were obtained by storing whole
gonads dry at about 4°C. While fertilization of eggs may be obtained
even after 6 to 7 days of dry storage, a high hatching rate is only to be
expected after periods not exceeding 36 hr storage. Long-term storage
has been achieved successfully with sperm, but not with eggs, by
freezing in glycerol and diluted sea water to a temperature of -79°C.
At least 6 months later the sperm were viable and crosses were made
between spring and autumn spawning herring (Blaxter, 1957) and
between different races of spring spawners (Blaxter and Hempel, 1961).
Storage of gametes within the dead parent’s body does not seem to
be successful and the fertilization rate was very low after I8 hr in
herring. Stroganov (1938) found in Cuqklosa voZgemia that the sperm
started to die 10-60 min after the death of the parent, if the testis wm
left in situ.
D. Fertilization
Fertilization in Clupea pallaaii was described by Yamamoto (1958)
as being normally monospermic. He showed that immediately following
sperm entry the fertilization membrane, which was a protein structure,
withdrew from the chorion thus forming a perivitelline space. Into this
space are extruded the droplets of the cortical alveoli (Volodin, 1956).
Yanagimachi and Kanoh (1953) found that the calcium ion concentration was critical for successful sperm entry. Yanagimachi (1957)
described a factor bound to the egg membranes of C l u p p a W i that
caused quiescent sperm to become active if brought near it. This