Showing papers in "Publications of the Seto Marine Biological Laboratory in 1987"

Underground Vertical Distributions of Macrofauna and Root in a Mangrove Forest of Southern Thailand

Abstract: In a mangrove forest of southern Thailand, underground vertical distributions of macrofauna and root biomass were investigated to a depth of 1 m. While smaller roots were distributed more or less evenly, larger roots were restricted to shallower layers. Animals were more abundant in shallower layers, but some of them penetrated into the deepest. Relation between the distribution of animals and that of larger roots is discussed. Cross-shore and for along-shore distributions of the benthic macrofauna in mangrove swamp have been studied quantitatively in various parts of the world (e.g. Warner, 1969; Day, 1974; Sasekumar, 1974; Frith et al., 1976; Shokita et al., 1983; Shihe & Fuxue, 1985). But the quantitative data on the underground vertical distribution of it have not so far been presented. One of the reason is probably that matted roots of mangrove trees make it difficult to dig the substrate deeper. In the temperate salt marsh habitat, the root mat density of the plants has been known to play an important role in controlling the distribution of fiddler crabs (Ringold, 1979; Bertness & Miller, 1984). Likewise, the underground root system of mangrove forest is assumed to influence more or less the distribution of the burrowing animals there. In this paper, we report the vertical distribution of benthic macrofauna in relation to the root biomass in a mangrove forest of southern Thailand. Study site and methods The study site was located in a mangrove forest at Hatsaikhao village near Ranong (9°58'N, Publ. Seto Mar. Biol. Lab., 32 (4/6), 329-333, 1987. (Article 12) 330 K. WADA, A. KOMIYAMA & K. OGINO 98°38'E), southern Thailand. In December 1982, a plot of 15m X 20m was established about 50 m landward from the seaward fringe of the forest. The plot area was not flooded at normal high tides and the substratum was sandy mud, with scattered puddles in places. The temperature and salinity of the water in a puddle measured at 10:00 on 1 Dec. were 27.0°C and 27.28%0, respectively. The dominant tree species in the plot was Rhizophora apiculata Blume with only a few smaller trees of Bruguiera gymnorrhiza (L.) Lam. and B. cylindrica (L.) Blume. The maximum diameter and height of the trees were 44.5 em and 37.2 m, respectively. The basal area totalled 31.3 m2/ha and the stand density was 733 treesjha. Shrub measurements were 31500/ha in the density, 7.5 m2jha in basal area, 2.4 em in mean diameter and 3.1 min mean height. A trench (0.2 m X 15.5 m) was laid out in the plot between two big trees of R. apiculata (diameter: 44.5 and 43.6 em). Fresh weight of prop roots/pneumatophores above the ground of the trench totalled 63.8 kg. The water table of the trench was 28-30 em deep and the temperature and salinity of the underground water were 25.0°C and 22.98%a, respectively (10: 10 on 9 Dec.). The trench was subdivided into 31 compartments, each 0.5 m long and each compartment was further subdivided vertically into 10 layers of soil blocks to a depth of 1.0 m. The 310 soil blocks, each 0.2 m (width) X 0.5 m (length) X 0.1 m (depth), were cut by a hand saw from the smoothed wall of the trench. Each soil block was sieved by a net with I mm opening to collect living roots and animals. Living roots were sorted into eight diameter classes ( 50 mm) and weighed fresh. Animals were fixed in 10% sea-water formalin and the number of individuals of each species was recorded for each soil block.

Three Forms of Nauplius Y Type VIII Larvae (Crustacea : Facetotecta) from the North Pacific

Abstract: Three forms of nauplius y type VIII larvae (VIII-a, VIII-b, VIII-c) are described from Tanabe Bay on the Pacific coast of Japan. The type VIII larvae are characterized by a peculiar shape of the body, which is extremely flattened dorso-ventrally and with paired notches on anterior side. Three forms are discernible from each other in the armature of appendages as well as in the sculpture on the cephalic shield. In the present paper three forms of closely related nauplius y larvae (Crustacea: Facetotecta) are described from the North Pacific under the symbols VIII-a, VIIIb and VIII-c. The type VIII-a was provisionally designated in a former paper (Ito, in press) with a diagram which showed the principal pattern of its cephalicshield sculpture, though description of its detailed morphology has been postponed. The specimens were selected by me from a sample of a number of facetotectan larvae of different types which were found in a plankton sample collected by Mr. S. Ohtsuka and were sorted out by him. The sample was collected in Tanabe Bay on the Pacific coast of Japan by a horizontal tow of a small plankton net (4 July 1982). The specimens, which had originally been preserved in formalin solution, were mounted onto slide glasses with absolute glycerin and were examined with the phase-contrast or differential interference microscope. The terminology used in this paper follows It6 (in press). Before going further I would like to express my sincere thanks to Mr. S. Ohtsuka of Hiroshima University, who placed the material at my disposal. This study is supported in part by the Grant-inAid for Scientific Research, No. 62540567, from the Ministry of Education, Science and Culture, Japan. Nauplius y, type VIII-a

A Review of the Mullets with a Keel on the Back, Liza carinata Complex (Pisces : Mugilidae)

Abstract: Liza carinata complex, characterized by having a keel on the middorsal line in front of the spinous dorsal fin, is revised. This complex consists of the following three species: L. carinata ([Ehrenberg MS] Valenciennes in Cuvier & Valenciennes, 1836) occurs in the Red Sea and the eastern Mediterranean; L. klunzingeri (Day, 1888) occurs in the west coast of India, Pakistan and the Arabian Gulf (Persian Gulf); L. affinis (Gunther, 1861) occurs in China, Taiwan and Japan. A key, synonymies, descriptions and illustrations are provided for all these species. Some geographical variations are also discussed. Liza carinata complex is a distinct group characterized by having a keel on the middorsal line in front of the spinous dorsal fin. The members of this complex are distributed discontinuously in the tropical and temperate Indo-West Pacific region of the Northern Hemisphere, inhabiting estuarine and shallow coastal waters. They are unwarranted for being monophyletic and have been much confused taxonomically each other. However, it is evident that they belong to a distinct genus LizaJordan & Swain, 1884 which is characterized by having a pair of elongated posterior neural zygapophysis on the second vertebra. Mugil carinatu' ( =L. carinata) was described by Valenciennes in Cuvier & Valenciennes (1836) on the basis of some materials from the Red Sea that Ehrenberg might have sent to him (Trewavas & Ingham, 1972). Although his description of this species is not fully diagnostic, he described clearly on the keel on the back. Publ. Seto Mar. Biol. Lab., 32 (4/6), 303-321, 1987. (Article I 0) 304 H. SENOU, T. YOSHINO & M. OKIYAMA In one of his great works, Day (1876) reported M. carinatus with full description on the basis of plural specimens from the Indian waters. After that, Day (1888a) named M. klunzingeri ( =L. klunzingeri) to the description and figure of Day (1876) according to Klunzinger's advice, and he newly added M. carinatus with full description from the Indian waters. Day (1889) provided a key to the mugilid fishes including these both species with the Red Sea as one of the localities. Pillay ( 1962) regarded M. carinatus and M. klunzingeri as the same species in a review of the Indian Mugilidae. Recently, however, Trewavas & Ingham (1972) stated that L. klunzingeri from the Indian waters differs from L. carinata from the Red Sea only in having usually a lower number of scales, and L. klunzingeri is a subspecies of L. carinata. On the other hand, Japanese and Chinese ichthyologists have traditionally used the name, M. carinatus or L. carinata for a mugilid fish which has a keel on the back, and is commonly found in these regions since Oshima (1919, 1922) erroneously identified L. affinis ( =M. affinis Gunther, 1861) as M. carinatus. M. affinis was described by Gunther (1861) on the basis of a specimen from Amoy, China. Although his description is detailed, he did not describe on the keel on the back. Recently, Song (1981) who is a reviewer of the Chinese mugilids used the name, affir.is for Osteomugil ophuyseni (Bleeker, 1859) (=M. cunnesius Valenciennes in Cuvier & Valenciennes, 1836). In the present paper, we have reviewed L. carinata complex on the basis of the specimens from nearly all previously known localities including the type materials, and recognized the following three species: L. carinata ([Ehren berg MSJ Valenciennes in Cuvier & Valenciennes, 1836) occurs in the Red Sea and the eastern Mediterranean; L. klunzingeri (Day, 1888) occurs in the west coast of India, Pakistan and the Arabian Gulf (Persian Gulf); L. affinis (Gunther, 1861) occurs in China, Taiwan

A Comparative Study of Some Larval Stages of Penaeus monodon and Penaeus merguiensis (Crustacea : Decapoda) from Indonesia

Abstract: The nauplius VI, protozoea II and mysis II of Penaeus monodon and P. merguiensis from Indonesian waters have been described and illustrated. The similarities and the differences between the two species have been observed. The comparison between the present study and that by previous authors have been made. Setation on endopod of maxilliped I and maxilliped II of protozoea and mysis stages as specific characters for identification is suggested. Two species of economically important penaeid prawns, Penaeus merguiensis De Man, 1888, and, P. monodon Fabricius, 1798, are among the many penaeids found in Indonesian waters. Although it is well known that their larvae occur in the coastal waters and are often mixed together (Noor-Hamid, 1976), accurate identification of their wild larvae is now possible only for post-larvae and juveniles, and identification at earlier stages is not yet succeeded. Larval stages of these species have already been described by some authors based upon materials from India (Silas et al., 1978) and the Philippines (Motoh, 1979; Motoh & Buri, 1979). Their information is available for identification of these larvae in Indonesian waters to certain extent, but some problems, which are probably related to difference of material andjor accuracy in observation, must be cleared before it is applied to Indonesian materials. In the present paper, larval stages of these two species, especially nauplius VI, protozoea II and mysis II, are described and compared on the basis of specimens reared in the laboratory, paying special attention to the type and number of setae on the appendages. Larvae of two species of penaeid prawns, Penaeus monodon and P. merguiensis, reared from eggs spawned in the laboratory were received from the Brackishwater Aquaculture Development Centre, Jepara. The larvae were preserved in 10% formalin and were used for morphological observation. Dissection of appendages was performed in 10% glycerin and drawings were made with Projectina, a micro photographic and drawing instrument. For each larval stage of the two species, 10 specimens were randomly taken for measurements with a micrometer eyepiece. The identification of substages is based on that used by Motoh (1979). Body lengths of nauplii were measured along the midline from apical to caudal margins, exclud-