Íslenskar landbúnaðarrannsóknir - 01.09.1978, Page 53

SPAWNER-RECRUIT RELATIONSHIP 51
TABLE 3. Data base, Ellidaár
Removals from Ellidaár
1 Year 2 Trap TC 3 4 Rod 5 6 7 Stock 8 9 Com. total CR Grand total of removals
Below RB Above RA Total RT Below BB Above BA Total BT
1966 3770 284 1008 1292 — — 534 - -
1967 4057 383 974, 1357 - - 968 100 2425
1968 2503 519 1129 1648 2 109 111 - -
1969 2930 480 853 1333 170 334 504 - -
1970 - 382 620 1002 97 152 249 - -
1971 2117 382 836 1218 - - 235 - -
1972 - 454 1279 1733 - - 530 - -
1973 4993 786 1490 2276 235 241 476 - -
1974 6314 - - 2033 - - - - -
1975 6387 - - 2071 - - - 30 -
1976 - - - 1292 ■ - - - - -
1977 ~ 4000 - 1400 - - - — —
ment. For example, if the run was judged
to be ,,weak,“ then no ftsh or very few fish
were taken for sale. Stocking eíforts via the
release of sac fry were initiated during this
first documentary period. The second
documentary period extends from 1956 to
1970. Features of this era include a
marked improvement in stocking
techniques, including the release of
yearlings and smolts in addition to the sac
fry, the completion of the second dam,
Ellidavatn, and the opening of extensive
new rearing and spawning areas above the
new dam. As in the other documentary
periods, there were several severe floods.
The third documentary period is the ex-
pansive period now in progess since 1971.
It is characterized by an increase in
catches not seen before.
METHODS
The data of Table 3 was prepared from
records of the Rafmagnsveita Reykja-
víkur, the files of the Veidimálastofnunin,
and the sources cited by Eiríksdóttir
(1974). All figures actually tabled are not
estimates but counts. For the purposes of
Table 4, estimates of missing values have
been prepared according to the protocol
below.
Col. 2, Trap (Table 3), TC, is a manual
count from 1933-1959 but it is an elec-
tronic count thereafter (±3% error ac-
cording to Hannes Pálmason, engineer).
The counter was broken in 1970, 1972,
and again in 1976. The figures for
1970-1972 were derived by estimating the
total run from the catch by a parabolic