摘要：Loligo opalescens, market squid, live less than a year and die
after a short spawning period, before all oocytes are expended.
The maximum lifetime fecundity of a female can be estimated
by counting all oocytes in the ovary just before initial ovulation
(potential fecundity, EP) and subtracting from EP the number of
oocytes remaining in the ovary (residual fecundity, ER) at the end
of the spawning period. During the spawning period no oogonia
are produced, hence the standing stock of oocytes declines as they
are ovulated. This decline in the number of oocytes is correlated
with a decline in mantle condition and an increase in the size of
the smallest oocyte. For a L. opalescens female of 129 mm dorsal
mantle length EP was estimated to be 3844 oocytes and ER was
estimated as 834 oocytes; thus our estimate of maximum lifetime
fecundity (EP-ER) is 3010 oocytes. The dry weight of 3844 eggs was
equivalent to 65.6% of the dry body weight of a 129 mm female
at the beginning of the spawning period. The close agreement
between the decline in body weight and the standing stock of
oocytes during the spawning period indicates that the production
of eggs is largely, if not entirely, fi nanced by the conversion of tissue
to eggs.
As the fi shery for L. opalescens occurs only on their spawning
grounds, and market squid die after completing all spawning (all
bouts of egg depositions), it is possible to calculate the fraction of
the potential fecundity that escapes the fi shery. To do this we used
an indirect method to compute the mean fecundity in the catch
and then subtracted this average total fecundity from the estimated,
average potential fecundity. These calculations indicate
that, during the period December 1998 through December 1999,
32.6% of the reproductive potential of the catch escaped capture.
This indicates that it may be practical to use escapement fecundity
as a way to monitor the California fi shery for L. opalescens.
