Table 1.
The sampling areas and methods used to collect marine teleost eggs in this study.
Fig 1.
Sampling stations of marine teleost eggs in 2009 and 2012–2016 in this study.
The area within the rectangle in the left map is enlarged on the right. Circled letter c, g, h, and t, open circle, and black dot indicate the sampling stations; the details about each sampling area are listed in Table 1. Dashed line means 200m depth contour.
Table 2.
Primers used to amplify three regions on eggs and adult fish.
Table 3.
The PCR conditions employed.
Table 4.
GenBank accession numbers of sequences read from fish eggs and adult specimens obtained by this study.
Table 5.
Marine fish eggs and larvae surveys (including leptocephali) in the western North Pacific from the literature.
Fig 2.
Neighbor-joining tree of 12S rRNA sequences for the eggs and four genera of eels (Ophisurus, Echelus, Ariosoma, and Gnathohpis).
E01-E16 indicates each egg. Others are sequences from four genera of eels and from Okamejei kenojei (as outgroup species). Numbers next to the branches are bootstrap values (>50%).
Fig 3.
Neighbor-joining tree of 16S rRNA sequences for the eggs and four genera of eels (Ophisurus, Echelus, Ariosoma, and Gnathohpis).
E01-E16 indicates each egg. Others are sequences from four genera of eels and from Okamejei kenojei (as outgroup species). Numbers next to the branches are bootstrap values (>50%).
Fig 4.
Neighbor-joining tree of COI sequences for the eggs and five genera of eels (Ophisurus, Echelus, Ariosoma, Gnathohpis, and Moringua).
E01-E16 indicates each egg. Others are sequences from five genera of eels and from Okamejei kenojei (as outgroup species). Numbers next to the branches are bootstrap values (>50%).
Fig 5.
The egg morphologies of four species of Ophichthidae and Congridae.
(A, B) Ophisurus macrorhynchos. (C, D, E) Echelus uropterus. (F) Ariosoma majus. (G, H, I) Gnathophis heterognathos. The letters in the lower left regions of the photographs are the specimen identification numbers. Scale bars, 1 mm.
Fig 6.
The distribution of eggs and leptocephali of Ophisurus macrorhynchos.
Eggs of O. macrorhynchos collected in this study (August 2016) are shown with red circles. Leptocephali of O. macrorhynchos (August 2013 and 2014, 9.8–44.5 mm TL) [7] are shown with blue diamonds. The other markings indicate surveys for fish eggs and/or larvae, but with no catches for these of O. macrorhynchos. Table 1 describes for the markings: circled letter c, g, h, and t, open circle, and black dot. Table 5 describes for the markings: bullseye, [3]; square, [6,30]; cross, [18]; spade, [21]; asterisk, [29]; crossed circle, [30]; up-pointing triangle, [31]; and down-pointing triangle, [32]. Arrows indicate ocean currents: The Kuroshio, Eastern Kuroshio Branch (EKB), and Tsushima Warm Current (TWC) [36]. Dashed line means 200m depth contour.
Fig 7.
The distribution of eggs and leptocephali of Echelus uropterus.
Eggs of E. uropterus collected in this study (August 2016) are shown with red circles. Leptocephali of E. uropterus (July-October 2010, 14.6–68 mm TL) [21] are shown with blue spade. The other markings indicate surveys for fish eggs and/or larvae, but with no catches for these of E. uropterus. Table 1 describes for the markings: circled letter c, g, h, and t, open circle, and black dot. Table 5 describes for the markings: bullseye, [3]; square, [6,30]; diamond, [7]; cross, [18]; asterisk, [29], crossed circle, [30]; up-pointing triangle, [31]; and down-pointing triangle, [32]. Arrows indicate ocean currents: The Kuroshio, Eastern Kuroshio Branch (EKB), and Tsushima Warm Current (TWC) [36]. Dashed line means 200m depth contour.
Fig 8.
The distribution of egg and leptocephali of Ariosoma majus.
Egg of A. majus collected in this study (August 2016) is shown with red circle. Leptocephali of A. majus are shown with blue squares (November to December 2000, 40–148 mm in TL, [30]), blue crossed circles (May 2004, 105–151 mm in TL, [30]), and blue up-pointing triangles (April to September during 2004–2009, 88.0–317.5 mm in TL, [31]). The other markings indicate surveys for fish eggs and/or larvae, but with no catches for these of A. majus. Table 1 describes for the markings: circled letter c, g, h, and t, open circle, and black dot. Table 5 describes for the markings: bullseye, [3]; square, [6]; diamond, [7]; cross, [18]; spade, [21]; asterisk, [29]; and down-pointing triangle, [32]. Arrows indicate ocean currents: The Kuroshio, Eastern Kuroshio Branch (EKB), and Tsushima Warm Current (TWC) in East China Sea [36] and the Kuroshio Current and Mindanao Current (MC) branched from the North Equatorial Current (NEC) [37]. Dashed line means 200m depth contour.
Fig 9.
The distribution of eggs and leptocephali of Gnathohpis heterognathos.
Eggs of G. heterognathos collected in this study (August 2016) are shown with red circles. Leptocephali of G. heterognathos are shown with blue bullseyes (October 2003, 3.8–59.8 mm TL, [3]), blue squares (November to December 2000, 6.8–88.8 mm TL, [6]), and blue down-pointing triangles (August 2014, 15.8–32.3 mm TL, [32]) The other markings indicate surveys for fish eggs and/or larvae, but with no catches for these of G. heterognathos. Table 1 describes for the markings: circled letter c, g, h, and t, open circle, and black dot. Table 5 describes for the markings: diamond, [7]; cross, [18]; spade, [21]; asterisk, [29]; square and crossed circle, [30]; and up-pointing triangle, [31]. Arrows indicate ocean currents: The Kuroshio, Eastern Kuroshio Branch (EKB), and Tsushima Warm Current (TWC) [36]. Dashed line means 200m depth contour.