Observations of the Reproductive Cycles and Ecology of the Common 
Brachyura and Crablike Anomura of Puget Sound, Washington 
Jens W. Knudsen 1 
It was the aim of this research project to 
study the growth and reproductive cycles of the 
Puget Sound Brachyura and Anomura as they 
are related to oceanographic and environmental 
conditions. These goals were designed to answer 
many of the basic questions concerning the local 
crab population and to serve as a basis for more 
restricted physiological experimentation dealing 
with behavior and reproductive cycles. A con- 
tinuous survey of the intertidal and near-shore 
crab fauna was made to determine the seasonal 
change in gonad development, egg production, 
the time of fertilization, deposition of eggs, and 
other related features. As many species of Ano- 
mura and Brachyura as could be accommodated 
were captured and maintained in running sea 
water aquaria for additional studies of food and 
feeding habits, ecdysis, copulation, and other 
phenomena linked to maturity and reproduc- 
tion. The aim to survey all Brachyura and Ano- 
mura in the southern Puget Sound area had to 
be modified to exclude the hermit crabs due to 
the extreme amount of time required for field 
observation of this group. It has been our goal 
to correlate reproductive activity of all of these 
species with annual environmental changes so 
far as possible and to determine trigger mech- 
anisms involved in the reproductive cycles. Con- 
siderable experimentation was attempted along 
these lines as is discussed herein. 
ACKNOWLEDGMENTS 
A research project of this nature has required 
the help and support of many institutions 
and individuals. To the Division of Biological 
Sciences of the National Science Foundation 
that has generously granted Pacific Lutheran 
University funds for this research , 2 the prin- 
1 Department of Biology, Pacific Lutheran Univer- 
sity, Tacoma 44, Washington. 
Manuscript received June 5, 1962. 
cipal investigator and those students who re- 
ceived research experience and financial aid wish 
to express their thanks. The Metropolitan Park 
Board of Tacoma has rendered a tremendous 
service in providing research space at the Point 
Defiance Aquarium; we wish to thank them, 
and especially Cecil Brosseau, for their help 
with space, equipment, and invaluable informa- 
tion. We wish to acknowledge the special lab- 
oratory space and facility donated by Dr. S. C. 
Eastvold and the Pacific Lutheran University. 
The writer wishes to express his indebtedness 
to biology majors who have served on this 
project. Especially helpful have been the efforts 
of Bert Freeman and Lloyd Dillingham; in ad- 
dition, other student assistants served one or 
more semesters on the grant: Ron Barbour, Ray 
Herbig, Gary Vestal, Ruth Olsen, Pat Lingel- 
bach, and Ron Heyer. The art work was done 
by Ron Heyer. Of invaluable aid have been the 
suggestions and help rendered by other carci- 
nologists, especially Dr. Josephine F. L. Hart 
Carl of the Provincial Museum, Victoria, British 
Columbia, and Dr. John S. Garth of the Allan 
Hancock Foundation, University of Southern 
California, Los Angeles. 
FIELD COLLECTING AND STUDY AREAS 
Three main sites were used within the area 
of Tacoma for year-long study of the southern 
Puget Sound crabs. These sites are somewhat 
variable in nature and thus offer a good cross- 
section of the different types of habitat within 
Puget Sound. Collecting was confined to the 
intertidal area because adequate dredging facility 
was not available. 
The most frequently visited site was that of 
Titlow Beach. This is a curved beach situated at 
the southern end of the Tacoma Narrows where 
the bay is fairly broad and is protected by pilings 
2 N. S. F. grant G-9066. 
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