Tokioka, Takasi

Publications of the Seto Marine Biological Laboratory

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TitleDROPLETS FROM THE PLANKTON NET -XIX. AGLIMPSE UPON CHAETOGNATHS AND PELAGICTUNICATES COLLECTED IN THE LAGOON WATERNEAR NOUMEA, NEW CALEDONIA-Author(s)Tokioka, TakasiCitationPUBLICATIONS OF THE SETO MARINE BIOLOGICALLABORATORY (1960), 8(1): 51-53Issue Date1960-05-30URL http://hdl.handle.net/2433/174703RightType Departmental Bulletin PaperTextversionpublisherKyoto UniversityDROPLETS FROM THE PLANKTON NET XIX. A GLIMPSE UPON CHAETOGNATHS AND PELAGIC TUNICATES COLLECTED IN THE LAGOON WATER NEAR NOUMEA, NEW CALEDONIA'· 2 J T AKASI TOKIOKA Seto Marine Biological Laboratory, Sirahama During the expedition to New Caledonia, paid by the Osaka Museum of Natural History in 1958, a few plankton samples were collected with a small net at the following stations : Stations in Noumea Port in the lagoon water SE off Noumea near the w barf of Kuto, Ile des Pins Date Nov. 14 Nov. 6 Nov. 13 Haul Distance 10-0m two surface tows 4-0m Four species of chaetognaths and eight forms of pelagic tunicates were found in the collection. They are : -Chaetognaths 1. Sagitta enjlata GRASSI 2. Sagitta robusta DoNCASTER 3. Sagitta oceania GRAY 4. Krohnitta pacifica (AIDA) Pelagic tunicates 1. Thalia democratica var. orientalis ToKIOKA 2. Dolioletta gegenbauri var. tritonis (HERDMAN) 3. Oikopleura longicauda (VoGT) 4. Oikopleura fusijormis FoL 5. Oikopleura dioica FoL 6. Oikopleura parva LoHMANN 7. Stegosoma magnum (LANGERHANS) 8. Fritillaria borealis f. sargassi (LoHMANN) ---------------1) Scientific Results of the Melanesia Expedition, No. 5. 2) Contributions from the Osaka Museum of Natural History, No. 59 and Contributions from the Seto Marine Biological Laboratory, No. 345. Publ. Seto Mar. Biol. Lab., VIII (1), 1960. (Article 4) 52 T. TOKIOKA The abundance of S. enflata and S. oceania in the lagoon water is common to this area and lagoons of the Palao Islands (TOKIOKA, 1942) and the Tuamotu Islands (RosE, 1953). In lagoons of the Palao Islands there occurred a considerable number of S. bedfordii DoNCASTER when I collected the samples. This species was, however, quite absent in the present collection examined. Some specimens of S. oceania were dissected to ascertain my identification. The specimens from this area seem to attain the maturity at a considerably smaller body size than those found in the lagoon water of the Palao Islands. Namely, a 4.5 mm long individual was found having the seminal vesicles ruptured and the ovaries reaching the middle of the anterior fin. Many of 5.5-6.1 mm long individuals were found matured, too. Table 1. Armature formulae of Sagitta oceania GRAY found in the material. Body length Tail segment Hooks Anterior Posterior in % teeth teeth 4.4mm 26.0 8-8 4-4 8-8 ----·--· 4.5 34.0 6-6 3-3 7-7 --------5.1 28.8 7-8 5-5 11-12 -- ----- -5.5 33.1 7-7 4-4 8-8 -~·-5.9 31.6 8-8 5-6 8-8 5.9 29.4 7-7 4-4 10-10 6.1 29.3 7-7 6-6 12-12 6.3 27.6 7-7 5-6 13-14 ---~~-----6.7 32.3 ? 6-7 ? ----~------- -··· 7.0 27.3 7 6 11 Of the pelagic tunicates, solitary forms of Thalia democratica were all of var. orienta/is ToKIOKA in which the lateral palps of the atrial aperture are distally bifurcated. This feature is very prominent in the present specimens, as even 1.5-2 mm long embryos are already provided with bifurcated palps. The abundance of 0. longicauda and 0. dioica was also seen in the appendicularian fauna of the lagoon water of the Palao Islands. In addition, 0. cornutogastra AIDA was met with rather frequently in lagoons of the Palao Islands, but it was not found ToKIOKA, T. (1942): Systematic studies of the plankton organisms occurring in Iwayama Bay, Palao. III, Chaetognaths from the bay and adjacent waters. Palao Tropical Bioi. St. Studies, Vol. II, No. 3, pp. 527-548. RosE, M. (1953) : Quelques renseignements sur le plankton des Iles Tuamotu. Bull. Mus. Nation. Hist. Nat., Tom. XXV, pp. 456-462. -52-Droplets from the Plankton Net, XIX 53 in the lagoon water near Noumea. F. borealis f. sargassi was represented here by only smaller forms. The trunk was less than 543,u (434,u on an average) and the tail was less than 900,u (807 ,u on an average) in length. The relative abun-dance of 0. dioica in Noumea Port may be accepted as indicating a considerable stableness of the port water. Table 2. Occurrence of chaetognaths and pelagic tunicates. *···less than 1%. Port of Lagoon water Kuto SE off Noumea I Ile des Total Noumea A B Pins Sagitta enjlata 87 29 37 I - 153 Sagitta robusta 3 - 1 I - 4 --Sagitta oceania 45 57 89 - 191 Krohnitta pacifica 1 - - - 1 Sagitta spp. juv. or damaged 20 11 44 I - 75 Thalia democratica sol. - 33 58 greg. 6 452 448 -------134 90 143 Dolioletta gegenbauri tritonis Amme 4 10 16 Oikopleura longicauda 36 112 184 1 333 Oikopleura fusiformis 1 7 5 - 13 Oikopleura dioica 72 4 4 ?1 81 ---·-Oikopleura parva 2 - - - 2 Stegosoma magnum - - - 1 1 --Fritillaria borealis sargassi 4 421 710 - 1135 -----Appendicularians juv. or damaged 1 88 227 - 316 -53-Percen-tage 36.1 1.0 45.0 * 17.7 ---17.7 1.0 4.3 .. -~--* * 60.3 16.8 

DROPLETS FROM THE PLANKTON NET -XIX. A GLIMPSE UPON CHAETOGNATHS AND PELAGIC TUNICATES COLLECTED IN THE LAGOON WATER NEAR NOUMEA, NEW CALEDONIA-

Takasi Tokioka

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DROPLETS FROM THE PLANKTON NET -XIX. A GLIMPSE UPON CHAETOGNATHS AND PELAGIC TUNICATES COLLECTED IN THE LAGOON WATER NEAR NOUMEA, NEW CALEDONIA-

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