APPENDIX. 
107 
Season of 1909— Having formed the theory that the striped bass 
caught at Bouldin Island are almost all sexually immature, and having 
so far been unable to locate their spawning beds, we hope that by 
penning the fish when caught they could be held until ripe. The 
penning of striped bass had been tried on the Atlantic coast without 
success and we knew they were exceedingly difficult to hold alive in 
captivity, yet we believed that with a sufficiently large pen, fenced off 
in the river, they could be held. By act of the State legislature the 
months of May and June had been made a close season on striped bass 
for net fishermen. We employed a fisherman with boat and suitable 
nets to fish during this time for the hatchery. 
The run of spawn bass this season was exceedingly poor. Very few 
of the fish were to be found near Bouldin Island or on the river below. 
While ripe males were not uncommon, the females taken were most of 
them sexually immature. Only one apparently ripe female was taken, 
and from this fish only about 5 per cent of the eggs were hatched. The 
capture in the river of only green or spawned out fish would indicate 
that the river is not the place of spawning; but every conceivable place 
was fished during both the day and the night—the tule flats, the sloughs, 
the interior of the flooded island were fished with the result we were 
not nearer to the solution of the problem of where the striped bass 
spawn. 
We built one pen in the edge of the river 3 by 40 feet in which the 
water stood about 6 feet deep at the outer edge and 2 feet deep at 
the inner side next the bank, with tides growing at one end and the rest 
partly overhung with willows. 
We found that immature female bass and mature male bass caught in 
gill nets and carefully handled and placed in lively condition in this 
pen would live five or six days. The same kind of fish caught in fyke 
nets would live ten or twelve days. Female bass apparently nearly in 
spawning condition caught in gill nets could not be kept twenty-four 
hours. They injure themselves in some way when caught in the net and 
do not recover. We caught no nearly ripe females in the fyke net. 
Thinking possibly there was not current enough in the pen we had, we 
built a pen 16 by 20 feet by 5 feet deep, divided into two compartments 
10 by 16 feet each. The framework was of 2 by 4 pine, and the sides 
and bottom covered with woven wire fencing. The pen was floated and 
anchored in the current of Potato Slough. The fish placed in this pen 
did not live as long as in the other. The current seemed to be too 
strong for them. In neither pen did they struggle to get out, but 
seemed not to recover from their struggles when caught. In all fifty 
bass were penned. Our experience would show that the striped bass 
can not be held in pens until they mature unless possibly the pen be 
