88 
ZOOLOGICAL SOCIETY BULLETIN 
THE FOOT OF THE DAM 
The limit of the lampreys’ advance. 
Photograph by C. M. Breder, Jr. 
At such times when the water is allowed to 
flow over this dam it gravitates rapidly at a 
steep angle over smooth boards. To these the 
lampreys cling, inching their way upwards 
sometimes half way to the top before exhaustion 
overtakes them and catapults them back again. 
At other times the water is allowed to issue from 
flume pipes alongside the dam. When this is 
done the lampreys attempt to stem the powerful 
current set up, frequently leaping into the air 
in their attempts to pass up 
turbulent waters. The only 
practicable way to capture 
them while so engaged is to 
dip blindly into the roily 
water with a long-handled 
dip-net. This is not as diffi¬ 
cult as might be imagined 
for such is their abundance 
during the height of the run 
that one may be brought up 
every few dips and not in¬ 
frequently two or even three 
at a time. When the dam is 
overflowing it is more simple 
to capture them as one may 
walk along the base of it 
and slip a net under them as 
they adhere to the sloping- 
boards. 
seen on May 20. The great¬ 
est numbers were seen on 
May 8. 1 Generally, how¬ 
ever, the season may be said 
to extend from about the 
middle of March to the mid¬ 
dle of M ay with its peak in 
the latter part of April. 
The maximum size obtained 
had a length of thirty-three 
inches and a weight of two 
pounds, four ounces, while 
the minimum was twenty- 
four inches long and 
weighed fourteen ounces. 
The average was twenty- 
nine inches with a weight 
of one pound, eleven ounces. 
There is of course con¬ 
siderable individual varia¬ 
tion in the weight at a given 
length, dependent upon 
plumpness, general condi¬ 
tion, and so on, but it may be roughly said that 
in ripe lampreys over two feet long, a little in 
excess of two ounces is added for eacli inch in 
length. Correlation with sex in this respect is 
practically negligible. 
As before noted, these animals are not pro¬ 
vided with jaws but while swimming and forcing 
1 I am indebted to Mr. W. Bennett, an entliuiastic 
woodsman of Redbank for these dates, as well as 
for valuable guidance about this territory. 
This year the lampreys 
put in their appearance on 
March 28, and were last 
CATCHING LAMPREYS 
Method by which the ninety-eight lampreys were captured. Dam and flume 
appear in the background. 
Photograph by C. M. Breder, Jr. 
