614 
Abstract.-striped bass, Morone 
saxatihs, in the Coos River, Oregon, are 
derived from natural colonists from San 
Francisco Bay, which in turn were in- 
tentionally transplanted from the 
Hudson River. Because of founder ef- 
fects, this unusually well-documented 
colonization sequence should have re- 
sulted in diminished genetic variabil- 
ity in the penultimate and ultimate 
populations, which may have been fur- 
ther compounded in the Coos River 
population by subsequent drastic re- 
ductions in its abundance. To test 
whether these sequential bottlenecks 
reduced genetic diversity we surveyed 
both nuclear DNA (nDNA) and mito- 
chondrial DNA (mtDNA) variation in 
the Coos River population and in both 
populations along the historical path- 
way that led to its founding. There was 
no evidence of reduced nDNA diversity 
among these populations at the three 
loci examined. However, the number of 
mtDNA haplotypes revealed decreased 
from 8 in the original Hudson River 
population, to 5 in the San Francisco 
Bay population, to only 1 in the Coos 
River population. This pattern of con- 
served nDNA diversity and reduced 
mtDNA diversity is consistent with a 
recent population bottleneck. Coos 
River striped bass have shown increas- 
ing levels of pathological hermaphro- 
ditism. We speculate that the reduced 
genetic diversity of the Coos River 
striped bass population may have led 
to a depensatory cascade involving her- 
maphroditism that inhibited reproduc- 
tion and recruitment, followed by in- 
creased levels of inbreeding as the 
population declined. 
Manuscript accepted 20 October 1997. 
Fishery Bulletin 96:614-620 (1998). 
Multiple population bottlenecks and 
DNA diversity in populations of wild 
striped bass, Morone saxatilis 
John R. Waldman 
Hudson River Foundation for Science and Environmental Research 
40 West 20th Street, New York, New York, 10011 
E-mail address: john@hudsonriver.org 
Reese E. Bender 
Oregon Department of Fish and Wildlife 
4475 Boat Basin Drive, Charleston, Oregon 97420 
Isaac I. Wirgin 
Institute of Environmental Medicine 
New York University Medical Center 
Long Meadow Road, Tuxedo, New York 10987 
Population bottlenecks are often 
invoked to explain lower than ex- 
pected levels of genetic diversity in 
wild populations of fishes (e.g. 
Bernatchez et al., 1989; Brown et 
al., 1992; Richardson and Gold, 
1997), but rarely is there detailed 
information available on the degree 
and duration of the bottlenecks. 
Striped bass ( Morone saxatilis ) of- 
fer an exception because sequentially 
established populations (Fig. 1) 
in historical times have experi- 
enced unusually well documented 
bottlenecks. 
Striped bass were introduced to 
the Pacific coast at San Francisco 
Bay in 1879 and 1882 (Stevens et 
al., 1987). The two plantings totaled 
approximately 430 individuals ( 132 
in 1879; approximately 300 in 
1882). All were yearlings collected 
in the Navesink and Shrewsbury 
rivers, New Jersey. The Navesink 
and Shrewsbury rivers are minor 
systems that do not support repro- 
duction by striped bass and that are 
located near the mouth of the 
Hudson River; the transplants were 
almost certainly part of the proxi- 
mal Hudson River striped bass 
population. The transplanted year- 
lings rapidly established a popula- 
tion in San Francisco Bay which 
reproduced in its two main tributar- 
ies: the Sacramento and San Joaquin 
rivers. The introduction of striped 
bass to San Francisco Bay has been 
viewed as one of the few highly suc- 
cessful introductions of non-native 
fishes (Raney, 1952); within 10 years 
of the original introduction striped 
bass were available in commercial 
quantities in California waters. 
The first striped bass captured in 
Oregon waters were two adults 
taken in Coos Bay in 1914 (Morgan 
and Gerlach 1 ). These fish were va- 
grants (or less likely, the offspring 
of vagrants) from the San Francisco 
Bay population, the only possible 
source along the Pacific coast. Since 
1914, reproducing populations of 
striped bass became established in 
Oregon in the Coos, Coquille, Ump- 
qua, Smith, and Siuslaw estuaries. 
Of these, the Coos River population 
was the largest and most studied. 
1 Morgan, A. R., and A. R. Gerlach. 1950. 
Striped bass studies on Coos Bay, Oregon 
in 1949 and 1950. Oregon Fish Commis- 
sion Contribution 14, 31 p. 
