Species identification by morphology
A total of 15 species were identified from fish eggs, belonging to 12
families; 12 species were identified from fish larvae, belonging to 12
families. One species, Dinematichthys iluocoeteoides was shared
between the fish egg and larva samples. Four egg samples (E009, E017,
E018, and E019) could not be identified due to partial damage (i.e.,
missing the key feature for identification); two larva samples (L011 and
L012) were unable to be identified due to the missing key feature for
identification.
A morphological analysis apparently revealed 15 species from the fish
egg samples, of which 7 were identified using the characters of egg
diameter, oil ball, and pigmentation in the egg, and 8 were identified
using the features of egg diameter and/or oil ball. Based on our
observations, eggs of Pampus argenteus (E020, E021, and E022) are
1.39-1.41mm in diameter with an oil ball of 0.39mm and pigments evenly
distributed on the back of embryo and spread to the caudal stalk; there
are also pigments inside the oil ball. Eggs of Konosirus
punctatus (E011, E012, and E013) are 1.28-1.43mm in diameter with
dotted pigments evenly distributed on the back of the embryo.Trichiurus lepturus eggs (E032 and E033) are 1.90-2.00mm in
diameter with an oil ball of 0.48mm and a pair of pigments accumulated
on the head; there are a pile of pigments on the pectoral fin and the
ventral surface of tail. Pseudaesopia japonica eggs (E023, E024,
and E025) are 1.84-2.03mm in diameter with the absence of oil ball and
many star-shaped pigments on the embryo and yolk. The Scomber
japonicus egg (E027) is 1.02-1.38mm in diameter with an egg ball of
0.33mm and two parallel lines of pigments on the back of embryo. TheDinemathichthys iluocoeteoides egg (E010) is 0.80mm in diameter
with an oil ball of 0.11mm and a dendritic pigment on the embryo.Larimichthys crocea egg (E014) is 1.70-1.21mm in diameter with
some small oil balls nearby a large yellow oil ball of 0.31mm.Scomberomorus niphonius eggs (E028, E029, and E030) are
1.60-1.70mm in diameter with an oil ball of 0.4mm. Acanthopagrus
schlegelii egg (E001) is 0.98-1.20mm in diameter with an oil ball of
0.20-0.23mm. Chrysochir aureus eggs (E004 and E005) are
070-0.79mm in diameter with an oil ball of 0.2mm. Coryphaena
hippurus eggs (E006, E007, and E008) are 1.35-1.46mm in diameter with
an oil ball of 0.26-0.36mm. The Sillago japonica egg
(E031) is 0.63-0.70m in diameter with an oil ball of 0.15-0.18mm oil
ball. Lateolabrax japonicus eggs (E015 and E016) are 1.26-1.33mm
in diameter with no oil ball. Auxis rochei eggs (E002 and E003)
are 0.95 mm in diameter with no oil ball. Saurida macrolepis(E026) is 0.90-0.97mm in diameter and has no oil ball.
A morphological analysis revealed 12 species of fish larvae that belong
to 12 families. Eleven species were identified by the characters of
dorsal fin, anal fin and pigmentation; one species was identified by
dorsal fin and anal fin characters. We observed that theChaeturichthys stigmatias larva (L004) has a dorsal fin of VII-22
rays, an anal fin of 19-20 rays, and star-shaped pigments under the
chest cavity and above and below the anus; also there is a large black
star-shaped pigment at the end of anal fin and buttock.Sebastiscus marmoratus larva (L015) has a dorsal fin of XII-11
rays and an anal fin of III-5 rays; there are dense pigments above the
chest cavity and 7-8 star-shaped pigment dots evenly arranged from the
anus to the caudal stalk. Larvae of Larimichthys polyactis (L009
and L010) each have a dorsal fin of X-31-36 rays, an anal fin of II-9
rays and one little pigment on the abdomen and another on the buttock
below the chest. Chelidonichthys spinosus larva (L005) has a
dorsal fin of IX-16 rays, an anal fin of 16 rays, and star-shaped
pigments on the head, chest cavity, abdomen, ventral fin and first
dorsal fin. Acanthogobius hasta larva (L001) has a dorsal fin of
VIII-18 rays, an anal fin of I-16 rays, and a large star-shaped pigment
on the base of ventral fin; there are star-shaped pigments above the
bladder, above and at the end of digestive tract and on the base of anal
fin and the base of caudal fin. Engraulis japonicus larva (L007)
has a dorsal fin of 14-16 rays, an anal fin of 15-18 rays, and
star-shaped pigments on the head, anterior gill cover and above the
digestive tract; there is a little pigmentation in the lower caudal fin.Callionymus enneactis larva (L003) has a dorsal fin of IV-8 rays,
an anal fin of 7 rays, and star-shaped pigments arranged in parallel on
the back of body, on the midline of body side and from the anus to the
caudal stalk as well as a dendritic melanin on the abdomen.Benthosema pterotum larva (L002) has a dorsal fin of 12 rays, an
anal fin of 17 rays, and one large chrysanthemum-like pigment in the
front of abdominal sac and another at the end of digestive tract. The
larva (L006) of D. iluocoeteoides has a dorsal fin of 80 rays, an
anal fin of 59 rays, and pigments evenly distributed on the top of fish
head, on the gill caps behind the eyes, on the back from the anus of
abdomen to the caudal stem, and on the end of body spine. Harpadon
nehereus larva (L008) has a dorsal fin of 11-13 rays, an anal fin of
13-15 rays, and seven large melanin plaques in the chest. Salanx
ariakensis larvae (L013 and L014) have a dorsal fin of 12 rays, an anal
fin of 25-27 rays, and pigments evenly distributed on the upper part of
digestive tract and the base of fin membrane of abdomen. Takifugu
xanthopterus larva (L016) has a dorsal fin of 16-18 rays, an anal fin
of 14-16 rays, and dense pigments at the end of snout, on the back of
body, and above and below the chest cavity.