THE BEKAVXOUR AND PHYSIOLOGY OF HERRING AND OTEER CLUPEIDS 309
5. Nitrogenous extractives of tissues
Shewan (1951) gave the proportion which nitrogenous extractives
formed of the total muscle nitrogen. The clupeid fishes, with a value of
14 to 18%, lay between the flat fish-gadoid group (9 to 14%) and the
elasmobranchs (34 to 38%). (Hunter and Dauphinke (1925) found that
Clupea pallaaii also occupied this position with respect to the arginase
concentration of its tissues.)
Shewan (1955) found a close similarity in the composition of the
basic amino acids between the herring and Ab8afi7&zJ and also that
the herring (and other pelagic species) contained higher concentrations
of histidine, and lower concentrations of carnosine and anserine than
demersal species. It is paradoxical that the muscles of a pelagic, active
fish should have low levels of carnosine and anserine; Yudaev (1949,
quoted by Shewan, 1951) found that this condition was usually
associated with lack of mobiliiiy and endurance. Yudaev (1950) also
found that high histidine and low carnosine and anserine was characteristic of freshwater fishes. Hughes (1959a) suggested that there may be
seasonal variations in the amounts of free amino a i d s , especially
histidine, in the herring.
Data from various authors were compiled by Shewan (1951), who
compared the trimethylamine oxide content of fish from fresh and salt
water. Pornolobus had less (185 mg%) than the herring (250 mgyo),
but the difference between these clupeids was a good deal less than
between other comparable fresh and sea water species. Seasonal
variation of trimethylamine oxide content of Clupea harengus and
Sprattus spattus has been reported (Ronold and Jakobsen, 1947;
Hughes, 1959b). However, the presentation of the data as a proportion
(mg per 100 g fish) does not allow one to decide if this is a change in
absolute values or another reflexion of the loss of fat.
6. Effect of diet
F m i s (1958), working with Sardinups caeruku, found that if these
fish were fed a high protein diet then the concentration of free aspartic
acid in the tissues fell. It did not fall in fish fed a carbohydrate diet.
Farris found that the proportion of fish having free aapctrtic acid and
alanine in the tissues varied inversely with the condition of the iish,
suggesting that during starvation amino acids were mobilized.
H. Salinity tolerance and osmo-regulation
1. Tolerance
The clupeids have freshwater, marine and anadromous representatives. Many of the marine forms come close inshore either when
5. Nitrogenous extractives of tissues
Shewan (1951) gave the proportion which nitrogenous extractives
formed of the total muscle nitrogen. The clupeid fishes, with a value of
14 to 18%, lay between the flat fish-gadoid group (9 to 14%) and the
elasmobranchs (34 to 38%). (Hunter and Dauphinke (1925) found that
Clupea pallaaii also occupied this position with respect to the arginase
concentration of its tissues.)
Shewan (1955) found a close similarity in the composition of the
basic amino acids between the herring and Ab8afi7&zJ and also that
the herring (and other pelagic species) contained higher concentrations
of histidine, and lower concentrations of carnosine and anserine than
demersal species. It is paradoxical that the muscles of a pelagic, active
fish should have low levels of carnosine and anserine; Yudaev (1949,
quoted by Shewan, 1951) found that this condition was usually
associated with lack of mobiliiiy and endurance. Yudaev (1950) also
found that high histidine and low carnosine and anserine was characteristic of freshwater fishes. Hughes (1959a) suggested that there may be
seasonal variations in the amounts of free amino a i d s , especially
histidine, in the herring.
Data from various authors were compiled by Shewan (1951), who
compared the trimethylamine oxide content of fish from fresh and salt
water. Pornolobus had less (185 mg%) than the herring (250 mgyo),
but the difference between these clupeids was a good deal less than
between other comparable fresh and sea water species. Seasonal
variation of trimethylamine oxide content of Clupea harengus and
Sprattus spattus has been reported (Ronold and Jakobsen, 1947;
Hughes, 1959b). However, the presentation of the data as a proportion
(mg per 100 g fish) does not allow one to decide if this is a change in
absolute values or another reflexion of the loss of fat.
6. Effect of diet
F m i s (1958), working with Sardinups caeruku, found that if these
fish were fed a high protein diet then the concentration of free aspartic
acid in the tissues fell. It did not fall in fish fed a carbohydrate diet.
Farris found that the proportion of fish having free aapctrtic acid and
alanine in the tissues varied inversely with the condition of the iish,
suggesting that during starvation amino acids were mobilized.
H. Salinity tolerance and osmo-regulation
1. Tolerance
The clupeids have freshwater, marine and anadromous representatives. Many of the marine forms come close inshore either when