Pacific Plate Biogeography, with Special Reference to Shorefishes

NUMBER 367 33
Its occurrence in Hawaii is possibly the result of
dispersal from Japan via the Kuroshio extension.
CHANIDAE
The milkfish, Chanos chanos, is the sole member
of the family. It attains a length of more than a
meter, spawns in the sea, and the fry may enter
freshwater, where they remain for several years
until they are about 600 mm or more in length;
thereafter, they return to the sea (Herre and
Mendoza, 1929). The milkfish is widely distributed
in the tropical Indo-Pacific. It ranges from
the east coast of Africa eastward to the eastern
Pacific.
CHEILODACTYLIDAE
The morwongs are a family of moderate-sized
fishes (to about 400 mm FL) with pelagic eggs
(Tong and Vooren, 1972). The family is in need
of revision, but probably contains fewer than 20
species.
The general distribution of the morwongs can
be described as antiequatorial. They are distributed
in the southern hemisphere on the warmtemperate,
rocky coasts of the continents and
continental islands, ranging as far north as southern
Queensland (Grant, 1978), in Australia. In
the northern hemisphere they range from Japan
and Korea south to about Hong Kong. On the
Pacific Plate there are only two species: Cheilodactylus
vittatus, with a north-south disjunct distribution
(Hawaiian Islands, Lord Howe Island, New
Caledonia), and an undescribed species known
only from Rapa and Easter Island (Randall, In
press b, c).
CHIROCENTRIDAE
The wolf herrings consist of a single genus,
Chirocentrus, and two species of free-swimming,
voracious, near-shore fishes with pelagic eggs. The
wolf herrings are often reported (on hearsay) to
reach a length of 12 ft (3.6 m). I have been unable
to locate the initial report listing this size, which
I have traced only as far back as Bleeker
(1869-1875). The next largest size that I have
been able to locate for wolf herrings is 4.5 ft (1.4
m, Grant, 1978). Reports over 1 m are uncom-
mon.
The wolf herrings are absent from the Pacific
Plate, but are widely distributed in the Indo-West
Pacific, from the eastern Indian Ocean to Fiji,
adjacent to the western margin of the Pacific
Plate.
ClRRHITIDAE
The hawkfishes comprise 9 or 10 genera and
about 35 species (Randall, 1963, and pers. comm.;
Lavenberg and Yanez, 1972; Lubbock, 1978) of
small- to moderate-sized (maximum, 550 mm
SL), benthic, reef-dwelling fishes. One species is
limited to the Caribbean and St. Helena, in the
eastern Atlantic; one species is endemic to Ascension,
in the eastern Atlantic; one species is endemic
to the west African coast; and one is endemic
in the eastern Pacific. The remaining 31
species are restricted to the Indo-Pacific, except
that two species (Oxycirrhitus typus, Cirrhitichthys
oxycephalus) range from the western Indian Ocean,
and one species (Cirrhitichthys serratus) ranges
from Guam (but see Myers and Shepard,
1981:343-344) and the Ryukyu Islands, into the
eastern Pacific. Of the 31 Indo-Pacific species, 14
do not occur on the Pacific Plate nonmarginally
and 17 do. Nine of the 17 are widely distributed
in the Indo-Pacific, seven occur only at Pacific
Plate localities (two also occur at Philippine Plate
localities, but all seven are considered here as
Pacific Plate endemics), and one species, Cirrhitichthys
serratus, has a remarkable distribution:
Guam (Kami et al., 1968; but see Myers and
Shepard, 1981:343-344), Maug (northern Marianas,
J.E. Randall, in litt.), Samoa (R.C. Wass,
ms.), questionably, Oahu (Randall, 1963, and in
litt.), and Gorgona Island (Colombia, eastern Pacific;
Randall, 1963). Cirrhitichthys serratus is the
only sedentary reef species I know that appears
to be limited to the Pacific Plate and the eastern
Pacific. Randall (in litt.) suspects that it may be