ALASKA SALMON INVESTIGATIONS IN 1900. 
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reservoir, and from it escapes through the narrow ditch already mentioned into the 
nursery, or rearing-pond, whence it passes through a short Hume into the lagoon. 
As far as the circumstances have permitted, the ripening-ponds have been dug 
rectangular in shape, and as opportunity affords they are walled up with rubble and 
cement. The doors are of broken rock and gravel, but it is the intention to cover 
these with cement also as soon as time permits. The fish do not ripen well in dirty 
water, and their frequent violent movements stir up any mud which may be on the 
bottom or in the interstices of the sides. The same movements of the fish tend to 
keep in suspension any slime or other foreign material, which thus passes out 
through the wasteway, and this is so slight where the ponds are walled solidly that 
no deleterious effects are apparent, even after the water has passed through several 
ponds full of ripening fish. 
All the upper ponds have sufficient fall between one and another for excellent 
aeration, a most important consideration where many fish are impounded. Covered 
pond No. 6 has the best arrangement for aeration, which may be described as follows: 
The feed water passes through a wooden trough suspended horizontally over the pond 
and extending longitudinally toward the center. The bottom of the trough is about 
4 feet above the surface of the pond, and is pierced by numerous auger holes, through 
which the water falls in tiny streams. Besides giving perfect aeration this method 
distributes the supply over such a large area that the impounded fish are less excited 
than is the case where the same volume enters in a single stream; they keep more 
quiet, ripen more quickly, and if they do leap do not strike against anything ivhich 
will bruise them, but merely fall back into the pond again. This arrangement will 
be extended to the other ponds whose relative elevations will admit of it, as oppor- 
tunity offers. The low ponds, No. 3, No. 4, and No. 5, have not given satisfaction, 
and this is due probably to lack of adequate aeration. No. 2, however, though on 
practically the same level as No. 3, is an excellent pond, but its superiority is thought 
to be due to being tightly walled, and consequently cleaner than its mate. No. 5 is 
expected to prove satisfactory after it has been cemented. 
When a pond is to be gone over for ripe fish the water is lowered to a depth of 
about 24 inches, or knee-deep, the waste gates being arranged to let it fall to that 
depth, but no less, for fear of smothering the fish. A panel of slat fencing is then 
lowered into the water at one end and pushed slowly toward the opposite side of the 
pond, the spawn-takers wading behind it. The fish are carefully dipped up, 
examined, and if found ripe for spawning placed in a floating car, made of slats, for 
future attention; if still green they are freed in the pond behind the fence. This 
method of handling the impounded fish has proven the best with the delicately 
organized red salmon, and explains the importance of having the ponds of a regular 
shape; thus every fish can be handled and every ripe one secured with the least 
injury. After the operation has been completed the fence is removed and the live- 
car of ripe fish towed gently alongside the stripping platform, of which there is one 
at each ripening-pond. 
Stock fish for the natchery are secured oy seining crews working under the 
orders of the superintendent of the association’s canneries at Karluk Spit. These 
, crews are composed of natives who are borne on the cannery rolls. The principal 
seining-ground is on the northern shore of the lagoon, opposite the hatchery, from 
