NOTES O N BALEEN PLATES AND O N ARRANGEMENTOF
PARASITIC BARNACLES OF GRAY WHALE.RICE**へr
A* ANDDALE＼TOSHIO KASUYINTRODUCTION) caughtduring thesutsubosru
ithcirhcs
Es(eggray whalnitagitsevnewe werei
ilhT¥l¥ngCompany,Rich‑ihs
i
Fetn
Mol
Deeht
onof
i
att
hores
hestt
966‑67arof1ewint
heMarineM ammalotssuedt
cpermiti
ifit巴nci
lsaicep,underasianrofimond,Cal.BureauofCommercialFisheries,wemadesome.SlLaboratoryoftheU
aci
goloi
B‑esarertluse. These rselcanr
acbitiss and paraeatleen plaeb
hson tnoitavresbo.
eportedher

THEASYMMETRYOFWEAROFBALEENPLATES‑
softwograywhales. Measure
etalebaleen phengthoft. 1showsthelgiFpoftheiothetnetiegumlh,fromtetalemadeonevery5thor 10thpr
mentswe,8‑769.1o,Nr)etneocstedsie(ywhalarfagsoetalnpee
lahb
t0d9n
hat0.
,5h0t. 1.lgi
Fe.
ni
eguml
hstetaci
dnei
ni
ckl
la.B
w
ei
rv
oi
r
et
sop.
oyko
fT
yoti
sr
ev
in,Uetutitsn
hIc
aresnReaec• O・・ MarineMammalBiologicalLaboratory,BureauofCommercialFisheries.
,.
tsn.Is.WhalesRe.RψicS乙1970,39‑43.
.2oN

40

KASUYA AND RICE

plate along the lateral edge. As seen in this figure, the length of the baleen plates
in the anterior part of the series is not bilaterally symmetrical. The plates on
the right side are shorter than those in the corresponding positions on the left side.
This asymmetry appears to be the rule among the California gray whales, foramong 31 whales observed by us, there were only 3 animals in which the baleen
plates of the anterior part of the right side were longer or nearly equal with thoseof the left.
As seen in Fig. 2 the distance between growth marks on the surface of thebaleen plates is the same on the left and right sides, but the plates on the rightside show heavier wear on the lingual edge. So it is reasonable to conclude that
this asymmetry has been caused not by the slower growth of the right plates butby heavier wear on the right.
1967-830
E~20

Ul

<I>

0Q. 10

c

<I>

~00.0

1966-192....0-..c 20
Clc<I>.....I

1050

100150No. of baleen plates
Fig. 2. Length of baleen plates of gray whales, no. 1967-8 12.6 m female and no. 1966192 13.6 m female. Opencircle indicates the right and the closed the left. Curves are
drawn by hand.

The gray whale feeds on benthic organisms and sometimes even swallows
sand or pebbles (Tomilin, 1954; Pike, 1962; Rice and Wolman, in press). Scammon (1874) and Wilke and Fiscus (J961) reported that feeding gray whales had
surfaced with head and lips besmeared with mud, and that they apparently had
expelled mud through the baleen. These observations suggest that gray whales
scoop the mud or sand on the bottom to collect benthic organisms.
Gunther (1949) mentioned that the movements of the rorquals from side toside appears to be restricted by the structure of body and that fin whales have theSci. Rep. Whales Res. Inst.,
No. 22, 1970.

41>/OTESO NGRAYWHALE. MEASUREMENTSOFBALEEN PLATESOFTABLE1CALIFORNIAN GRAYWHALE
No.ofbalee
npl
ates% ofl
engt
hofrightt
otheleft

Sampl
eno.
Range
Mean
可tandarderrorABcRightLeft

3160.
9‑105.
686.
61.
92

16511
‑120.
082.
24.
2
920
55.
6‑116.
774.
53.
31

91
3
9‑1
72
1
55.
8II
1
38‑1
63
1
55.
5

・A ：ルfaxi
muml
ength.
B Lengthatmiddleofs
er
ies.
er
ior
‑mo
stbr
istle.
C: At50cmfromant

Fig.3. Ro
strum reg
ionoft
hegray w
hale, Top: lefts
ide,bottom: rights
ide. For
expl
anallo
ns
e
et
e
xt.

tendencyt
osw
imonones
i
det
otu
r
ns
ha
rp
lyt
ooned
i
rect
io
n. Thes
amewoul
du
l
tf
or
betr
uea
lsofo
rgraywhalesf
ee
di
n
ga
tt
heb
ot
t
om, andi
twoul
d bed
i伍 c
themt
os
c
oo
pt
h
ebottomw
it
ht
hean
t
e
r
io
rpa
r
toft
hel
ow
e
rl
i
pw
h
i
l
esw
immin
gi
nnormalpos
tu
re. Thisissupporte
dbyt
heobser
v
at
iont
hatt
h
enumbe
rofco
lo
ni
e
so
fba
r
nac
le
si
n
f
e
st
i
ngt
hel
e
f
ts
i
deoft
heheadr
e
gi
o
nexc
e
e
dst
hato
ft
h
er
i
g
h
ts
i
de.
Ont
h
es
k
i
noft
h
er
i
ghts
i
deoft
h
er
os
trumweo
f
t
e
nobs
er
v
e
dman
yheal
e
do
ropen
wo
unds
,probabl
ys
cr
at
c
hesc
a
u
s
e
dbyhards
u
bst
anc
e
so
nt
he.
bot
t
om.
From t
hes
e co
ns
i
derat
io
n
s we s
pecul
a
te t
ha
tt
h
ea
s
ym metr
ic wear oft
hebalee
npl
at
e
soft
h
egraywhalei
sther
e
s
ul
toff
ee
di
n
g movementsi
nwh
ic
ht
hewhaless
coo
pt
h
es
e
d
ime
n
tmo
s
t
l
ywi
t
ht
h
er
ig
h
tant
er
io
rr
e
g
io
noft
heba
le
enpl
at
e
roNS.
Noasymmetrywasfoundinthen山 nbero
fb
alee
np
lat
es(Table1).

、Sci.Rep.WhalesRes.Inst.
,λro.22,1970.

42

KASUYA AND RICE

WATER CURRENT ON THE BODY SURFACE SUGGESTED BY THE
ORIENTATION OF THE BARNACLES

There are many colonies of barnacles, Cryptolepas rhachianecti DALL, on theskin of gray whales. They are especially numerous on the rostrum and flippers,
fairly numerous on the upper edge of the lower lip, the area between the eye andthe base of the flipper, and on the tail peduncle. There are few barnacles on theother parts of the body.
These barnacles are directed approximately towards the anterior end of thewhale, and all the barnacles in a colony are oriented in the same direction. The
orientation of barnacles at any point on the body is nearly the same in all whales.
We think that the orientation of the barancles is affected by the direction of
the water current at the point where the barnacles are growing, and the anterior
end of the barnacles coincides with the mean direction of the current.

-~c~~~~~------Fig. 4.

~-----,

Diagramatic figure of the orientation of barnacles on the gray whale

Fig. 4 is a diagrammatic figure of the orientation of the barnacles on the graywhale. This figure is based on sketches of each part of the body of six animals,
and some photographs taken in the same whaling season. Each small rod represents
approximately one colony. We found no significant bilateral asymmetry in theorientation.
On the upper jaw and the dorsal side of the tail peduncle the water seems toflow obliquely upward. But in the area between the angle of the gape and theanterior insertion of the flipper, the water seems to flow obliquely downward fromthe gape to the flipper. These flow patterns agree with those on the body of Delphinus and Phocoenoides, as determined from the arrangement of dermal ridges andfrom a photograph of a swimming Delphinus (Purves, 1963). Purves (loc. cit.)
Sci. Rep. Whales Res. Inst.,
No. 22, 1970.

NOTES ON GRAY WHALE

43

reported that the dermal ridges on the flippers and flukes are arranged perpendicular
to the leading edge. But in the case of the gray whale the barnacles are oriented
obliquely from the anteroproximal to the posterodistal edge of the fins on both
dorsal and ventral sides. Probably the gray whale usually holds its flippers in aventroposterior position, so the mean direction of the current will be oblique tothe long axis of the flipper. On the tail flukes it is not unreasonable to think thatthe current moves in a posterodistal direction, when the flexibility and somewhat
posteriorly convex shape of the flukes are considered.
On the ventral side of the body the water seems to flow parallel with the bodyaxis. The orientation of some colonies of barnacles suggests a downward flowslightly below the mid-line of the tail peduncle.
ACKNOWLEDGEMENTGreatest thanks are due to Mr. Allen A. Wolman of the Marine Mammal BiologicalLaboratory, who kindly assisted at the whaling station. Without his help, ourstudy would not have been accomplished. We owe very much to Prof. Masaharu
Nishiwaki of the Ocean Research Institute, who provided the opportunity for Kasuya
to study the gray whale in the United States. The cooperation of Mr. John Caito
and Mr. Charles Caito of the Del Monte Fishing Company is also acknowledged.
They provided the facilities to collect and study the gray whales.
REFERENCESGUNTHER, E. R., 1949. The habits of fin whales. Discovery Rep., 25: 113-42.
PIKE, G. C., 1962. Migration and feeding of the gray whale (Eschrichtius gibbosus). J. Fish. Res. Bd. Can.,19 (5): 815-38.
PURVES, P. E., 1963. Locomotion in whales. Nature, 197 (4865): 334-7.
RICE, D. W., and A. M. '\TOLMAN, (In press). The gray whale: life history and ecology. Amer. Soc. Mammal., Spee. Puhl. No. 3.
SCAMMON, C. M., 1874. The marine mammals of the northwestern coast of North America. John H. Carmany& Co., San Francisco. 319 pp.
ToMILIN, A. G., 1954. Adaptive types in the order Cetacea. ,Zool. :(h. 33 (3): 677-92 (cited in Pike, G. C.,
1962).
WILKE, F., and C. H. Fiscus, 1961. Gray whale observations. J. Mammal. 42 (1): 108-9.

Sci. Rep. Whales Res. Inst.,
No. 22, 1970.