Ægir - 01.01.1982, Page 46

hrygningarstofnar lélega árganga, ef skilyrði eru
léleg. Engin augsýnileg ástæða virðist til þess að
ætla að loðnustofninn sé undanþeginn þessum
lögmálum náttúrunnar.
Summary:
Capelin larvae investigations
1977—1981
Investigations on the spawing grounds at Iceland
have been carried out in the years 1976—1981 by
the Marine Research Institute. A part of the
material from those investigations on the capelin
larvae in 1977—1981 is presented here.
The capelin spawns in mars-april at temperature
of 5°—7° C. Incubation period is 3—4 weeks. The
larvae hatch 9.4% at 5 mm, 60.0% at 6 mm and
30.6% at 7 mm. The larvae start feeding soon after
hatching. In a month the larvae reach 12 mm
length and in 3 month 4—6 cm in average. The
hatching period is shown in fig. 1. Length distribu-
tion for all the years is shown in fig. 2. Mortality in
percentage, based on the length distribution from
all surveys in each year, is shown in fig. 3.
From estimated, based on Norwegian and Cana-
dian observations on egg mortality, 70% egg
mortality from spawning to hatching, and
fecundity investigations on Barents Sea capelin,
the egg mass and spawning stock each year is
calculated as shown in table 1.
It is concluded that unfaverable conditions in
the sea after hatching and during the summer are
mainly responsible for the relatively poor year-
classis of capelin produced in 1977—1981.
Helstu heimildir.
1. Bakke og Bjorke, 1973. Diving observation on Barents
Sea capelin at the spawing grounds of Northern Norway.
Fisk. Dir. Skr. Ser. Hav Undens., 16; 4.
2. Dragesund, Gjosæter and Monstad, 1973. Estimates of
stock size and reproduction of the Barents Sea capelin in
1970—1972. Fisk. Dir. Skr. Ser. Hav Undens., 16; 4.
3. Eyjólfur Friðgeirsson, 1976. Observations on! spawning
behaviour and embryonic development of the Icelandic
capelin. Rit Fiskideildar 5, 4.
4. Frank and Leggott, 1979. Subtidal occurrence of larval
capelin (Mallotus villosus) as related to variation on the
intertidal distribution of their eggs. ICES/ELH.
Symp./DA:Poster 10. Woodshole 1979. Not published.
5. Gjosæter and Monstad, 1973. Fecundity and egg size of
spring spawning Barents Sea capelin. Fisk. Dir. Skr. Ser.
Hav Undens., 16; 4.
6. Hjálmar Vilhjálmsson, 1981. Vetrarvertíðin 1980. Loðnu-
veiðarnar 1980. Loðnunefnd.
7. Prokhorov, 1965. Ekologia moivy Barentsevo morja í
perspektivy ego promyshlennogo izpolsovanija. Trudi
P.I.N.R.O. 19 Murmansk.
8. Svend-Aage Malmberg, 1979. Astand sjávar og fiskstofna
við ísland. III. Ástand sjávar og loðnu. Ægir. 11. tbl.
9. Ástand nytjastofna á íslandsmiðum og aflahorfur 1980.
Hafrannsóknir 20. hefti.
10. Ástand nytjastofna á Islandsmiðum og aflahorfur 1981.
Hafrannsóknir 22. hefti.
11. Árlegar seiðarannsóknaskýrslur. 1970—1981.
A. Nýklakin lirfa. 5,6 mm löng. 18 sólarhr. eftir
frjóvgun.
B. 4 sólarhr. eftir klak. 6,7 mm löng. 3 vikum
eftir frjóvgun.
34 — ÆGIR