Subtidal Clam Populations: Distribution, Abundance, and Ecology

237 Pages·2009·9.45 MB·English

Subtidal Clam Populations:
Distribution, Abundance, and Ecology
D.R.Hancock
T. F. Gaumer
G. B. Willeke
G.P.Robart
J. Flynn
OREGON STATE UNIVERSITY
SEA GRANT COLLEGE PROGRAM
Publication no. ORESU-T-79-002
OREGON
9~

Fish &Wildlife
A cooperative effort of the Oregon State
University Sea Grant College Program and the
Oregon Department of Fish and Wildlife
authors
DANIL R. HA~COCK Assistant Professor of Biological Oceanography at Oregon State University.
mOMAS F. GAUMER Project Leader, ~larine Region, of the Oregon Department of Fish and Wildlife.
GAIL (BREED) WILLEKE Research Assistant (unclassified) in Biological Oceanography at Oregon

State University,

GREGORY P. ROBART Fish Biologist, t,1arine Region, of the Oregon Department of Fish and Wildlife.
JOAN FLYNN Research Assistant (unclassified) in Biological Oceanography at Oregon State

University.

acknowledgment
This study could not have been undertaken without the generous efforts of many people. The
authors are grateful to Edward Bryant of the National Science Foundation (RANN) and subse­
quently to William Wick of the Oregon State University Sea Grant College Program for support
in the conceptual stages.
Dale Snow, Jack Robinson, and Robert Loeffel of the Oregon Department of Fish and Wildlife
gave strong administrative support to the work.
For technical help during the difficult subtidal sampling, we are indebted to John Ratliff,
Norma Smallbone and Nancy Spencer for handling the OSU field sampling program, preparation of
gonad tissue, initial slide preparation, and testing of volume measurement techniques. Gail
Heineman assisted with the statistical analyses. Connie Morehouse prepared all the base maps,
some of the figures, and aided Bronwyn Hurd in the supervision of the publication. Jack
Robinson, Al Tyler, Robert E. Olson, and James E. ~1cCauley critically reviewed the manuscript.
We also thank Pam Wegner, tlargie Lamb, Geneva Weaver, Katherine Allen, and Joan Neuman for

typing the manuscript.

The Oregon State University Sea Grant College Program is supported cooperatively
by the National Oceanic and Atmospheric Administration, U.S. Department of Com­
merce, by the State of Oregon, and by participating local governments and pri­
vate industry.
The OSU Sea Grant College Program attempts to foster discussion of important marine issues
by publishing reports, sometimes dealing with controversial material. A balanced presentation
is always attempted. When specific views are presented, they are those of the authors, not
of the Sea Grant College Program, which does not take stands on issues.
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2
contents
Page
17 PART I General introduction
19 I.A. History of Oregon's commercial and recreational
bay clam fisheries
21 I.B. Scope of research
25 PART II Studies of the distribution of clams in Oregon's
estuaries and their commercial potential
25 II.A. Studies of the distribution of clams and other
biological and physical features

134 II.B. Gaper clam aging studies

136 II.C. Surveys of clam beds with commercial potential

174 II.D. Commercial bay clam fisheries

190 II.E. Economics - market conditions from harvest of

gaper clams
195 PART III Ecological studies of the gaper clam, Tresus
aapax
195 lILA. Growth and reproduction
228 III.B. Abundance of gaper clam larvae in lower Yaquina
Bay, Oregon for 12 January to 12 March, 1976
233 III.C. Haplosporidan study
239 PART IV Applications
239 IV.A. Research summary, conclusions and implications
3
LIST OF FIGURES
Figure
LA.I. -1 Commercial bay clam landings in Oregon, 1941-1975. 20
II.A.l.-l A map of coastal Oregon showing estuaries surveyed by the Oregon 26
Department of Fish and Wildlife (*not included in this study).
II.A.2. 1 Distribution of substrate materials in Nehalem Bay, Oregon. 32
II.A.2.-2 Distribution of gaper clams (Tresus capax) in Nehalem Bay, Oregon. 33
(See Fig. II.A.2.-l for areas not surveyed.)
IT.A.2. 3 Distribution of cockle clams (Clinocardium nuttallii) and butter 34
clams (Saxidomus giganteus) in Nehalem Bay, Oregon. (See Fig.
II.A.2.-l for areas not surveyed.)
II.A.2.-4 Distribution of eelgrass (Zostera marina) in Nehalem Bay, Oregon. 35
(See Fig. II.A.2.-l for areas not surveyed.)
ILA.2.-S Distribution of sea lettuce (Ulva sp.) in Nehalem Bay, Oregon. 36
(See Fig. II.A.2.-l for areas not surveyed.)
ILA.2.-6 Distribution of unidentified brown algae in Nehalem Bay, Oregon. 37
(See . II.A.2. 1 for areas not surveyed.)
ILA.2.-7 Distribution of unidentified red algae in Nehalem Bay, Oregon. 38
(See Fig. II.A.2.-l for areas not surveyed.)
II.A.2.-8 Distribution of substrate materials in Tillamook Bay, Oregon. 39
ILA. 2.-9 Distribution of gaper clams (Tresus capax) in Tillamook Bay, 40
Oregon. (See Fig. II.A.2. 8 for areas not surveyed.)
II.A.2.-10 Distribution of butter clams (Saxdomus giganteus) in Tillamook 41
Bay, Oregon. (See Fig. II.A.2. 8 for areas not surveyed.)
II.A.2. 11 Distribution of cockle clams (Clinocardium nuttallii) in 42
Tillamook Bay, Oregon. (See Fig. II.A.2.-8 for areas not
surveyed. )
II.A. 2. -12 Distribution of native littleneck clams (Venerupis staminea) in 43
Tillamook Bay, Oregon. (See Fig. II.A.2.-8 for areas not
surveyed. )
II.A.2.-l3 Distribution of irus clams (llacoma irus) in Tillamook Bay, Oregon. 44
(See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2.-l4 Distribution of softshell clams (Mya arenaria) in Tillamook Bay, 45
Oregon. (See . II.A.2.-8 for areas not surveyed.)
II.A.2.-lS Distribution of Baltic clams (Macoma balthica) in Tillamook Bay, 46
Oregon. (See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2.-l6 Distribution of bentnose clams (Macoma nasuta) in Tillamook Bay, 47
Oregon. (See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2.-l7 Distribution of California softshell clams (C~Jptomya californica) 48
and piddock clams (Zirfaea pilsbryi) in Tillamook Bay, Oregon.
(See . II.A.2.-8 for areas not surveyed.)
5
LIST OF FIGURES (Cant.)
II.A.2. 18 Distribution of ghost and mud shrimps californiensis 49
and Upogebia pugettensis) in Tillamook Bay, Oregon. (See Fig.
II.A.2.-8 for areas not surveyed.)
II.A.2. 19 Distribution of eelgrass (Zostera marina) in Tillamook Bay, 50
Oregon. (See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2. 20 Distribution of sea lettuce (Ulva sp.) in Tillamook Bay, Oregon. 51
(See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2.-2l Distribution of the green alga Enteromo~?ha sp. in Tillamook Bay, 52
Oregon. (See Fig. II.A.2.-8 for areas not surveyed.)
II.A. 2. -22 Distribution of the rockweed (Fucus sp.) in Tillamook Bay, Oregon. 53
(See Fig. II.A.2.-8 for areas not surveyed.)
II.A.2. 23 Distribution of substrate materials in Netarts Bay, Oregon. 54
II.A.2. 24 Distribution of gaper clams (Tresus in Netarts Bay, Oregon. 55
(See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2. 25 Distribution of butter clams (Saxidomus ) in Netarts Bay, 56
Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2.-26 Distribution of cockle clams (Clinocardium nuttaZlii) in Netarts 57
Bay, Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2.-27 Distribution of Manila littleneck clams (Venerupis phiZippinarium) 58
and native littleneck clams (V. staminea) in Netarts Bay, Oregon.
(See Fig. II.A.2.-23 for areas not surveyed.)
II.A. 2. -28 Distribution of irus clams (Macoma irus) in Netarts Bay, Oregon. 59
(See Fig. II.A.2.-23 for areas not surveyed.)
II.A. 2. -29 Distribution of softshell clams (Mya in Netarts Bay, 60
Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2.-30 Distribution of Baltic clams (Nacoma in Netarts Bay, 61
Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2.-31 Distribution of bentnose clams (Macoma in Netarts Bay, 62
Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
ILA.2.-32 Distribution of Bodega tellin clams Zina in 63
Netarts Bay, Oregon. (See Fig. II.A.2.-23 for areas not
surveyed. )
II.A.2.-33 Distribution of California softshell clams .'m.!hT.~~!1Jn californica) 64
in Netarts Bay, Oregon. (See Fig. II.A.2.
surveyed. )
I I.A. 2. -34 Distribution of piddock clams (Zirfaea in Netarts Bay, 65
Oregon. (See Fig. II.A.2.-23 for areas not surveyed.)
II .A. 2. -35 Distribution of ghost and mud shrimps (Callianassa californiensis 66
and Upogebia pugettensis) in Netarts Bay, Oregon. (See Fig.
IT.A.2.-23 for areas not surveyed.)
II .A. 2. -36 Distribution of eelgrass (Zostera marina) in Netarts Bay, Oregon. 67
(See Fig. II.A.2.-23 for areas not surveyed.)
6
LIST OF FIGURES (Cont.)
ion
II.A.2.-37 Distribution of sea lettuce (Ulva sp.) and other green algae in 68
Netarts Bay, Oregon. (See . II.A.2.-23 for areas not surveyed.)
II.A.2.-38 Distribution of green alga Enteromorpha sp. in Netarts Bay, Oregon. 69
(See Fig. II.A.2.-23 for areas not surveyed.)
II. A. 2. -39 Distribution of unidentified brown algae in Netarts Bay, Oregon. 70
(See Fig. II.A.2.-23 for areas not surveyed.)
ILA.2.-40 Distribution of unidentified red algae in Netarts Bay, Oregon. 71
(See Fig. II.A.2.-23 for areas not surveyed.)
II.A.2.-41 Distribution of substrate materials in Nestucca Bay, Oregon. 72
ILA.2.-42 Distribution of softshel1 clams (Mya arenaria) in Nestucca Bay, 73
Oregon. (See Fig. II.A.2.-4l for areas not surveyed.)
II.A.2.-43 Distribution of Baltic clams (!1acoma balthica) and irus clams (M. 74
irus) in Nestucca Bay, Oregon. (See Fig. II.A.2.-4l for areas not
surveyed.)
ILA.2.-44 Distribution of ghost and mud shrimps (Callianassa californiensis 75
and Upogebia pugettensis) in Nestucca Bay, Oregon. (See Fig.
II.A.2.-4l for areas not surveyed.)
ILA. 2. -45 Distribution of eelgrass (Zoster>a marina) in Nestucca Bay, Oregon. 76
(See Fig. II.A.2.-4l for areas not surveyed.)
II.A.2.-46 Distribution of sea lettuce (Ulva sp.) and Enteromorpha in Nestucca 77
Bay, Oregon. (See Fig. II.A.2.-4l for areas not surveyed.)
II.A.2.-47 Distribution of rockweed (Fucus sp.) in Nestucca Bay, Oregon. 78
(See Fig. II.A.2.-4l for areas not surveyed.)
II.A. 2. -48 Distribution of substrate materials in the Salmon River, Oregon. 79
ILA. 2. -49 Distribution of softshell clams (Mya arenaria) in the Salmon 80
River, Oregon. (See Fig. II.A. 2. -48 for areas not surveyed.)
II.A.2. 50 Distribution of Baltic clams (Macoma balthica) in the Salmon 81
River, Oregon. (See Fig. II.A.2.-48 for areas not surveyed.)
II .A. 2. -51 Distribution of ghost and mud shrimps (Callianassa californiensis 82
and Upogebia pugettensis) in the Salmon River, Oregon. (See Fig.
II.A.2.-48 for areas not surveyed.)
II.A.2.-52 Distribution of eelgrass (Zoster>a marina) in the Salmon River, 83
Oregon. (See Fig. II.A.2.-48 for areas not surveyed.)
ILA.2.-53 Distribution of sea lettuce (Ulva sp.) in the Salmon River, Oregon. 84
(See Fig. II.A.2.-48 for areas not surveyed.)
II .A. 2. -54 Distribution of substrate materials in Siletz Bay, Oregon. 85
II.A.2. 55 Distribution of softshell clams (t~a arenaria) in Siletz Bay, 86
Oregon. (See Fig. II.A.2.-54 for areas not surveyed.)
II.A.2. 56 Distribution of Baltic clams (Macoma balthica) in Siletz Bay, 87
Oregon. (See Fig. II.A.2.-54 for areas not surveyed.)
7
LIST OF FIGURES (Cont.)
Figure Caption
ILA. 2. -57 Distribution of ghost and mud shrimps (Callianassa oaliforniensis 88
and Upogebia pugettensis) in Siletz Bay, Oregon. (See Fig.
II.A.2.-54 for areas not surveyed.)
ILA.2.-58 Distribution of eelgrass (Zostera marina) in Siletz Bay, Oregon. 89
(See Fig. II.A.2.-54 for areas not surveyed.)
II.A.2.-59 Distribution of sea lettuce (Ulva sp.) in Siletz Bay, Oregon. (See 90
Fig. II.A.2.-54 for areas not surveyed.)
II.A.2.-60 Distribution of the green alga Enteromorpha sp. in Siletz Bay, 91
Oregon. (See Fig. II.A.2.-54 for areas not surveyed.)
II .A. 2. -61 Distribution of rockweed (Fucus sp.) in Siletz Bay, Oregon. (See 92
Fig. II.A.2.-54 for areas not surveyed.)
II.A. 2. -62 Distribution of substrate materials in Yaquina Bay, Oregon. 93
II .A. 2.-63 Distribution of gaper clams (7'resus capax) in Yaquina Bay, Oregon. 94
(See Fig. II.A.2.-62 for areas not surveyed.)
II .A. 2. -64 Distribution of butter clams (Saxidomus giganteus) in Yaquina Bay, 95
Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
II .A. 2. -65 Distribution of cockle clams (Clinocardiwn nuttallii) in Yaquina 96
Bay, Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
I LA. 2. -66 Distribution of native littleneck clams (Venerupis staminea) in 97
Yaquina Bay, Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
ILA. 2. -67 Distribution of irus clams (Macoma irus) in Yaquina Bay, Oregon. 98
(See Fig. II.A.2.-62 for areas not surveyed.)
II .A. 2. -68 Distribution of softshell clams (Mya arenaria) in Yaquina Bay, 99
Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
ILA.2. 69 Distribution of bentnose clams (Maooma nasuta) in Yaquina Bay, 100
Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
ILA.2.-70 Distribution of piddock clams (Zirfaea pilsbryi) and the pea pod 101
borer (Adula falcata) in Yaquina Bay, Oregon. (See Fig. II.A.2. 62
for areas not surveyed.)
II .A. 2.-71 Distribution of native oysters (Ostrea lunda) in Yaquina Bay, 102
Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
ILA.2.-72 Distribution of ghost and mud shrimps (Callianassa californiensis 103
and Upogebia pugettensis) in Yaquina Bay, Oregon. (See Fig.
II.A.2.-62 for areas not surveyed.)
II.A.2.-73 Distribution of eelgrass (Zostera marina) in Yaquina Bay, Oregon. 104
(See Fig. II.A.2.-62 for areas not surveyed.)
II.A.2.-74 Distribution of the green alga Enteromorpha sp. in Yaquina Bay. 105
Oregon. (See Fig. II.A.2.-62 for areas not surveyed.)
ILA.2.-75 Distribution of rockweed (Fucus sp.) in Yaquina Bay, Oregon. (See 106
Fig. II.A.2.-62 for areas not surveyed.)
II.A.2.-76 Distribution of substrate materials in Alsea Bay, Oregon. 107
8
LIST OF FIGURES (Cont.)
Figure
Il.A.2.-77 Distribution of gaper clams (Tresus capax) in Alsea Bay, Oregon. 108
(See . II.A.2. 76 for areas not surveyed.)
II.A.2. 78 Distribution of cockle clams (Clinocardiwn nuttallii) in Alsea 109
Bay, Oregon. (See Fig. II.A.2. 76 for areas not surveyed.)
ILA. 2. -79 Distribution of native littleneck clams (Venerupis staminea) in 110
Alsea Bay, Oregon. (See . II.A.2.-76 for areas not surveyed.)
II.A.2.-80 Distribution of softshell clams (Mya arenaria) and California III
softshells (Cryptomya californica) in Alsea Bay, Oregon. (See
Fig. II.A.2. 76 for areas not surveyed.)
II.A.2.-81 Distribution of ghost and mud shrimps (Callianassa californiensis 112
and Upogehia pugettensis) in Alsea Bay, Oregon. (See Fig.
II.A.2. 76 for areas not surveyed.)
ILA. 2. -82 Distribution of eelgrass (Zostera in Alsea Bay, Oregon. 113
(See Fig. II.A.2.-76 for areas not surveyed.)
II.A.2.-83 Distribution of sea lettuce sp.) in Alsea Bay, Oregon. 114
(See . II.A.2.-76 for areas not surveyed.)
II. A. 2. -84 Distribution of unidentified brown algae in Alsea Bay, Oregon. 115
(See Fig. II.A.2. 76 for areas not surveyed.)
II.A.2.-85 Distribution of substrate materials in the Siuslaw River, Oregon. 116
II.A.2.-86 Distribution of gaper clams (Tresus capax) in the Siuslaw River, 117
Oregon. (See Fig. II.A.2.-85 for areas not surveyed.)
II .A. 2. -87 Distribution of native littleneck clams (Venerupis staminea) in 118
the Siuslaw River, Oregon. (See Fig. II.A.2.-85 for areas not
surveyed. )
II.A.2.-88 Distribution of softshell clams (Mya arenaria) in the Siuslaw 119
River, Oregon. (See Fig. II.A.2.-85 for areas not surveyed.)
II.A.2.-89 Distribution of Baltic and irus clams (Macoma halthica and M. 120
irus) in the Sius1aw River, Oregon. Fig. II.A.2.-85 for
areas not surveyed.)
II.A.2.-90 Distribution of piddock clams (Zirfaea pUshryi) in the 121
Siuslaw River, Oregon. (See Fig. II.A.2.-85 for areas not
surveyed.)
ILA.2.-91 Distribution of ghost and mud shrimps (Callianassa californiensis 122
and Upogebia pugettensis) in the Siuslaw River, Oregon. (See
Fig. II.A.2.-85 for areas not surveyed.)
II.A.2.-92 Distribution of eelgrass (Zostera marina) in the Siuslaw River, 123
Oregon. (See Fig. II.A.2. 85 for areas not surveyed.)
ILA.2.-93 Distribution of the green alga Enteromorpha sp. in the Siuslaw 124
River, Oregon. (See Fig. II.A.2.-85 for areas not surveyed.)
II.A.2.-94 Distribution of substrate materials in lower Coos Bay and 125
South Slough, Oregon.
9
LIST OF FIGURES (Cant.)
Figure
Caption
II.A.2.-95
Distribution of gaper clams (Tresus capax) in lower Coos Bay and 126
South Slough, Oregon. (See Fig. II.A.2.-94 for areas not surveyed.)
II.A.2.-96
Distribution of butter clams (Saxidomus giganteus) in lower Coos 127
Bay and South Slough, Oregon. (See Fig. II.A.2.-94 for areas not
surveyed. )
ILA.2.-97
Distribution of cockle clams (Clinocardium nuttallii) in lower 128
Coos Bay and South Slough, Oregon. (See Fig. II.A.2.-94 for areas
not surveyed.)
II .A. 2. -98 Distribution of native littleneck clams (Venerupis staminea) in 129
lower Coos Bay and South Slough, Oregon. (See Fig. II.A.2.-94
for areas not surveyed.)
ILA. 2. -99 Distribution of piddock clams (Zirfaea pilsbryi) in lower Coos 130
Bay and South Slough, Oregon. (See Fig. II.A.2.-94 for areas
not surveyed.)
ILA.2. 100 Distribution of eelgrass (Zostera marina) in lower Coos Bay and 131
South Slough, Oregon. (See Fig. II.A.2.-94 for areas not surveyed.)
II.A.2.-l01 Distribution of unidentified green and red algae in lower Coos 132
Bay and South Slough, Oregon. (See Fig. II.A.2.-94 for areas
not surveyed.)
IT.A.2. 102 Distribution of unidentified brown algae in lower Coos Bay and 133
South Slough, Oregon. (See Fig. II.A.2.-94 for areas not
surveyed. )
I1.B.2.-l
Exterior annual rings on the shell of the gaper clam (Tresus 134
capax) .
IT.C.2. 1
Location of Areas lA, lB, and lC surveyed for commercial potential 140

in Tillamook Bay, Oregon.

II.C.2. 2 Location of Areas 1, 2, 3, and 4 surveyed for commercial potential 141

in Yaquina Bay, Oregon.

II.C.2.-3 Location of study area surveyed for commercial potential in lower 142

Coos Bay, Oregon.

ILC. 3.-1 Distribution and density of gaper clams (Tresus capax) in Areas 147

lA-C, Tillamook Bay, Oregon.

ILC.3.-2 Distribution and density of cockle clams (Clinocardium nuttallii) 148

in Areas lA-C, Tillamook Bay, Oregon.

I1.C.3.-3 Distribution and density of butter clams (Saxidomus giganteus) in 149

Areas lA-C, Tillamook Bay, Oregon.

II.C.3.-4 Distribution and density of native littleneck clams (Venerupis 150

staminea) in Areas lA-C, Tillamook Bay, Oregon.

II.C.3.-5 Distribution and density of irus clams (f~coma irus) in Areas 151

lA-C, Tillamook Bay, Oregon.

I1.C.3.-6 Distribution and density of bentnose clams (Macoma nasuta) and 152

California softshell clams (Cryptomya californica) in Areas lA-C,

Tillamook Bay, Oregon.

10