MAYAMA TSUTOMU

TAKEDA SATOSHI

TAMURA SEIICHI

WASHIO MASAHIKO

紀要類（bulletin）departmental bulletin pape

TAKEDA, SATOSHI

MAYAMA, TSUTOMU

TAMURA, SEIICHI

WASHIO, MASAHIKO

Tohoku University Repository (TOUR) / 東北大学機関リポジトリ

BENTHIC FAUNA IN ZOSTERA MARINA BEDS OFFASAMUSHI, NORTH JAPAN著者 TAKEDA SATOSHI, MAYAMA TSUTOMU, TAMURASEIICHI, WASHIO MASAHIKOjournal orpublication title東北大学浅虫臨海實驗所報告volume 18number 4page range 169-176year 1990-08-30URL http://hdl.handle.net/10097/00131484BuLL. MAR. BwL. STN. AsAMusar, ToHoKu UNiv., 18(4), 169-176, 1990 BENTHIC FAUNA IN ZOSTERA MARINA BEDS OFF ASAMUSHI, NORTH JAPAN'' 8ATOSHI TAKEDA2>, TSUTOMU MAYAMA, SEIICHI TAMURA and MASAHIKO W ASHI03l Marine Biological Station, TO!wku University, Asamushi, Aomori 039-34, Japan The benthic fauna in offshore Zostera marina beds at Asamushi, north Japan (40"53'N: 140"5l'E), where reclamation of the foreshore and construction had been carried out up until 1986, was investigated by trawling in June, 1988. The results were compared with those of investigations conducted in 1961 before the reclamation and construction, and the change in the fauna before and after· the reclamation and construction work was discussed. A large . number of small animals were collected together with Z. marina and silky sea weed in 1988, and it was fou:b.d tliaf the number of recorded· taxa had increased since 1961. However, almost all of the large animals, i.e., megalobenthos, recorded in 1961 were also collected or observed in 19$8, suggesting that benthic fauna in the Zostera beds off Asamushi had not been changed by the local reclamation and construction work INTRODUCTION In naturally occuiTing Zostera beds, certain species of benthic animal are abundant, and these are understood to constitute a characteristic fauna (e.g., KIKUCHI, 1966: 0RTH et al., 1984). Some species of fish spawn in these beds, and the hatched juveniles grow there (e.g., HARADA, 1962: KIKuCHI, 1966). Clarification of the composition of benthic fauna in Zostera beds is very important from viewpoints of both marine ecology and fisheries to determine the prey-predator relationships among benthic animals. Off Asamushi, north Japan (40'53'N: 140'51'E), Zostera marina grows thickly, and forms beds scattered on the shallow sea bottom at a depth of less than about 10 m. YusA et al. (1961) investigated the benthic fauna of t~o typical areas with and without Z. marina, and described the differences of species composition between them. After the investigations by YusA et al. (1961), the foreshore atAsamushi was reclaimed in order to built a bypass in 1972, and a yacht harbor in 19.78. Moreover, a fishing park was constructed at the tip of the yacht harbor in 1986. : The foreshore 1) Contribution from the Marine Biological Station, TOhoku University, No. 562. 2) To whom correspondence should be addressed. 3l~w ~-~w ~-wM~--~~~~ 169 170 S. TAKEDA ET AL. at Utoumai, where the fauna was investigated by YusA et al. (1961), was also ' reclaimed to build a bypass in 1979. This reclamation of the foreshore and con-struction projects transfigured the topography of the seashore at Asamushi. This was considered to influence the density and growth of Z. marina, and consequently the benthic fauna, as a result of the changes in the physical environment, such as water current and water exchange. The aim of this study was to clarify the species composition of benthic fauna in the Zostera bed off Asamushi, after the reclamation and construction work. Moreover, the transition of the fauna was clarified by comparison between the species compositions before and after the reclamation and construction. STUDY SITES AND METHODS Investigations of benthic fauna were conducted at the Zostera beds off Asamu-shi (40"53'30"N: 140"51'50"E) and Yunoshima Island (40"53'30"N: l40"51'20"E) (Fig. 1 ). Z. marina off Asamushi was about 50 em in length, and scattered on the sandy sea bottom. The bottom was flat and approximately 5 m below the water 40'-+- -7/::, .. ]? 1!.5" 35 -, I '77:9- 140' OGomejima Is. 0 Marine Biological Station ··;4 135' Yunoshima Is. 125" 130" a~.2 Asamushi Utoumai 5!.3 500m ---Fig. 1. Map of the seashore around Asamushi, Aomori prefecture. St. 1, 2 and 3 indicate the stations off Asamushi, Yunoshima Island and Utoumai, respectively, where benthic fauna in Zostera marina beds was investigated. BENTHIC FAUNA IN ZOSTERA BEDS OFF NORTH JAPAN 171 surface. Off Yunoshima Island, Z. marina was about 3 m in length, and distributed abundantly. The bottom had a gentle slope, and the depth from the water surface changed from about 1m to 5 m further offshore. Many round stones lay on the bottom. Benthic animals were collected by trawling (net size: height=50 em, width= 150 em, depth=200 em, mesh size=3.6 mm). Trawling was carried out for approxi-mately 300m along the ZoS{era beds off Asamushi on 16 June, 1988, and for about Table 1. Lists and individual numbers of vertebrates collected by trawling (mesh size= 3.6 mm) in Zostera marina beds off Asamushi (St. 1), Yunoshima Island (St. 2) and Utoumai (St. 3), north Japan. • and " indicate published {1961) and unpublished data obtained by YusA et al., respectively. 1988 June 1961 May• 1961 June** 1961 July** Taxa OSTEICHTHYES Aulichthys japonicus Syngnathus schlegeli Hypoptychus dybowskii Opistlwcentrus ocellatus Opisthocentrus zonope Enedrias nebulosus Pholis ornatus Gobius gymnauchen Acanthogobius lactipes Acanthogob~'us jlavimanus Ghaenogobius heptacanthus Gobiidae sp. Fugu verrniculare Fugu poecilonotum Sebaste3 inermis Sebaste3 schlegeli Sebastes oblongus Hexagrammos otakii Pseudoblennius percoides Bero elegans Pallasina eryngia Paralichthys olivaceus Limanda punctatissima Limanda yokohamae Kareius bicoloratus ~1 ~2 ~1 ~3 ~1 ~3 ~1 ~3 18 5 19 1 2 8 1 1 7 71 5 1 2 1 4 1 2 1 28 30 11 2 1 11 6 6 8 1 15 3 1 2 2 2 1 18 9 6 7 5 3 3 1 17 20 1 1 1 3 5 1 1 12 85 1 3 1 1 6 2 1 8 9 1 7 1 2 1 3 10 6 172 S. TAKEDA ET AL. BENTHIC FAUNA IN ZOSTERA BEDS OFF NORTH JAPAN 173 Table 2. Table 2. Lists and individual numbers of invertebrates collected by trawfing (mesh size=3.6 mm) (continued) in Zostera m~rina beds off Asamushi (St. 1), Yunoshima Island (St. 2) and Taxa 1988 June 1961 May* 1961 June** 1961 JuJy•• Utoumai (St. 3), north Japan. * and ** indicate published {1961) St. 1 St. 2 St. 1 St. 3 St. 1 St. 3 St. 1 St. 3 and unpublished data obtained by YusA et al., respectively. Dynoides dentisinus 1 Oyproniscus ovalis 7 14 Taxa 1988 June 1961 May* 1961 June•• 1961 July ... Tsopoda spp. 7 St. 1 St. 2 St. 1 St. 3 St. 1 St. 3 St. 1 St. 3 Anonyx ampulloides 4 PROTOZOA Harpinia miharacnsis 1 Foraminiferida spp. 40 37 Stenotlwe valida (?) 15 3 Pontocrates altamarinus 9 CNIDARIA Pleustes panopla 22 5 Olatfunema uchidai 3 13 9 5 Pantogeneia rostrata 27 1 Gonionema oshoro 1 2 15 5 Melita dentata 32 Haliclystm auricula 1 Maera spp, (1) 28 Paradexamine barnardi 57 29 PLATHEL11INTHES Hyale grandicornis (1) 5 Polycladida spp. 2 Eurystheus japonicus 555 15 Ampithoe spp. 108 115 NEMATODA Jassa Jalcata 145 25 Nematoda spp. 557 114 Oorophiufn spp. 92 10 Ericthonius pugnax 7 11 MOLLUSCA Oero:pus tubularis 30 Lepidozona albrechti 5 Gammaridea spp. 6 11 32 19 17 Ischnochitonina spp. (juv.) 4 Oaprella spp. 420 79 13 38 24 2 Nordotis discus 1 Heptaearpus pandaloides 36 129 NoWacmea schrenckii (juv.) 2 Heptacarpus geniculatus 2 Patellacea sp. (juv.) 1 Heptacarpus spp. 112 734 131 1047 30 306 Oantharidus jessoensis 11 754 Eualus spp. 5 27 1 113 7 Homalopoma sangarense 1 Orangon aifinis 21 11 17 8 3 3 5 Temanella turrita 4612 1479 Paguristes japonicus 1 . Stenotis cariniferus ll13 575 Pagurus middendorifii 10 4 AngWJta.ssiminea satsumana 34 Pagurus ohotensis 1 Reticuna.ssa japonica 16 2 3 3, Paguridea spp. 3 Gastropoda sp. A 104 Telmessus acutidens 2 2 14 3 7 Gastropoda sp. B 47 67 Charybdis japonica 1 Gastropoda sp. C 2 5 Gastropoda sp. D 5 ECTOPROCTA Episiplwn makiyamai Gymnolaemata spp. 8 Mytilidae spp. {juv.) 102 64 Patinopecten yessQensis {juv.) 71 100 BRACHIOPODA Hiatella flaccida 1 3 Atremata. sp. Idiosepius pygmaeus 32 14 29 15 3 ECHINODERMATA ANNELIDA Gnathophiurida sp. Ammphinomorpha spp. 51 1 Astropecten scoparius 3 Nereimorpha spp. 172 72 Asterina pectinijera 17 3 27 15 1 Spiomorpha spp. 16 5 Apltelasterias japonica 1 Drilomorpha spp. 4 Asteria$ amurensis 2 2 36 9 Terebellomorpha spp. 1921 15353 GlypWridaris crenularis 3 Serpulimorpha spp. 31 185 Temnopleurns hardwicki 1 Polychaeta spp. 4 2 2 2 Strongylocentrotus intermedius 2 Piscicolidae spp. 4 Strongylocentrotus nudus 2 Echinocardium cordatum ARTHROPODA Pycnogonida spp. 2 1 5 PROCHORDATA Ostracoda spp. 57 16 Oiona intestinalis 4 Lepeophtheirns goniistii 1 Ascidiacea spp. 1 5 Copepoda spp. 1569 272 Siriella wata.sd 54 3 29 159 15 262 72 Mysidacea spp. 1 10 22 5 38 3 Cumacea spp. 9 Tanaidacea spp. 9 5 Parantlmra japonica 14 1 Janiropsis longiantennata 2 1 I dotea ochotensis 1 174 S. TAKEDA ET AL. 150m along the beds off Yunoshima on 21 June, 1988. All specimens after collec-tion were preserved in 10% formalin solution. Benthic animals collected were sorted, identified and counted in the laboratory. Identification of the specimens was done mainly according to descriptions in the "New Illustrated Encyclopedia of the Fauna of Japan ( 1965 )". RESULTS AND DISCUSSION Taxa and individual numbers of benthic animals collected in June, 1988 are shown in Tables 1 and 2, together with published (1961) and unpublished data obtained by YusA et al. All vertebrates collected were Osteichthyes (Table 1). The number of species of bony fish collected at the Zostera beds off Asamushi did not change markedly between the investigations in 1961 and 1988. Among eight species collected in 1988, six i.e., Syngnathus schlegeli, Opisthocentrus .ocellatus, Hexagrammos otakii, Pseudoblennius percoides, Limanda yokohamae and Kareius bicoloratus, were record-ed in 1961. Gobies, collected abundantly in July 1961, did not appear in June 1988. According to the results of the investigations in 1961, they showed a tendency to be more numerous toward summer, suggesting that they arrive and become distributed in the Zostera beds seasonally. From the data of the 1988 investigation, they probably were not distributed in the beds. In 1988, two species, Aulichthys japonicus and Enedrias nebulosus, were newly recorded and seven species, Pholis omatus, Fugu vermiculare, Sebastes schlegeli, Sebastes oblongus, Bero elegans, Parali-chthys olivaceus and Limanda punctatissima, were not collected. Nevertheless, all the above species were observed in both years. These results indicated that the bony fish community did not change between 1961 and 1988 at this site. Flatfish had a tendency to be collected more frequently in the beds off Asamushi than in those off Utoumai and Yunoshima. This result may be related to the patchy distribution and low density of Z. marina on the sandy bottom off Asamushi, since the flatfish collected generally inhabit sandy soft bottom areas (YusA et al., 1961). Flatfish were collected in both 1961 and 1988 at the beds off Asamushi, confirming that Z. marina was relatively scarce there before the reclamation and construction work. At the beds off Yunoshima, only two species, A. japonicus and 0. ocellatus, characteristically inhabiting the Zostera beds (YusA et al., 1961), were collected. The small number of species of bony fish may be related to the abundant Z. marina. On the other hand, the beds off Utoumai disappeared after reclamation to built the bypass in 1979. The number of invertebrate taxa collected during the investigation in 1988 was considerably increased in comparison with that in 1961, especially Mollusca, An-nelida and Arthropoda. Almost all of the animals newly recorded in 1988 were so small that they could have passed through the trawling net (mesh size=3.6 mm). BENTHIC FAUNA IN ZOSTERA BEDS OFF NORTH JAPAN 175 These animals included, for example, Foraminiferida spp., Nematoda spp., Temanel-la turrita, Stenotis cariniferus, Angustassiminea satsumana, Terebellomorpha spp., Copepoda spp., Gammaridea spp., and so on. In the 1988 investigation, a great quantity of silky sea weed was collected together with Z. marina, especially off Yunoshima. The above small animals were considered to have been collected along with these silky sea weeds. Megalobenthos, such as Oladonema uchidai, Gonionema oshoro, Reticunassa japonica, Idiosepius pygmORJI.!s, Siriella watasei and Decapoda, were recorded in both 1961 and 1988. On the other hand, the numbers of individuals and taxa of Echinodermata collected in 1988 were lower than those in 1961. Nevertheless, other species except for Glyptocidaris crenularis were often observed on rocks and boulders in 1988. ·These facts suggested that the invertebrate community had not changed widely, as in the case of vertebrate. The number of taxa of benthic animals collected in the beds off Asamushi was higher than that collected off Yunoshima. In the beds off Asamushi, large shells of Saxidomus purpuratus, which inhabits sandy bottoms, were collected together with Z .. marina and silky sea weeds, indicating that the trawling was adequate for collecting items on the bottom. On the other hand, in the beds off Yunoshima where round stones lay on the bottom, no stones were collected, suggesting that the trawling net did not reach the bottom due to the large quantity of Z. marina and silky sea weeds. This difference as to whether or not the net reached bottom may be related to the higher number of taxa of benthic animals recorded in the beds off Asamushi than that off Yunoshima. On the other hand, in the beds off Yunoshima, many animals inhabiting the intertidal zone, e.g., Cantharidus jesso~usis and A. satsumana, were collected. Exposure of long leaves of Z. marina on the water surface was considered to create the conditions of the intertidal zone where these animals inhabit. As mentioned above, although the number of taxa of benthic animals recorded by the investigation in 1988, due to the numerous small animals collected, was higher than that in 1961 on the Zostera beds off Asamushi, the megalobenthos community did not change between the two years. These results suggest that the fauna was not changed by the local reclamation and construction work. We express our cordial thanks to Dr. TATSUO YusA for his willingness to make his unpublished data available. 176 S. TAKEDA ET AL. REFERENCES HARADA, E., 1962 A contribution to the ecology of the black rockfish, Sebastes inermis Cuvier et Valenciennes. Publ. Seta Mar. Bioi. Lab., 10, 307-361. KIKUCHI, T., 1966 An ecological study on animal communities of Zostera marina belt in Tomioka Bay, Amakusa, Kyushu. Publ. Amakusa Mar. Biol. Lab., 1, 1-106. OKADA, K., 1965 New Illustrated Encyclopedia of The Fauna of Japan. Hokuryukan Co., Ltd. Tokyo, Japan. 0RTH, R.J., K.L. HECK and J. VAN MoNTFRANS, 1984 Faunal communities in seagrass beds: A review of the influence of plant structure and prey characteristics on predator-prey relationships. Estuaries, 7, 339-350. YusA, T., T. HosHIAI, Y. SATO and S. KuBOTA, 1961 Study on the history of useful fish in coastal waters, I. The general conditions for maintaining investigation stations. Information on Bottom Fish, Hachinohe Branch Stn., TOhoku Reg. Fish. Res. Lab., 29, 22-29 (in Japanese). 

BENTHIC FAUNA IN ZOSTERA MARINA BEDS OFF ASAMUSHI, NORTH JAPAN

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BENTHIC FAUNA IN ZOSTERA MARINA BEDS OFF ASAMUSHI, NORTH JAPAN

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