August 3, 2010
Japan Agency for Marine-Earth Science and Technology
Overview
Scientists from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the Field Science Education and Research Center, of Kyoto University, and the Atmosphere and Ocean Research Institute, of the University of Tokyo, have created comprehensive inventories of marine life in the exclusive economic zone (EEZ) of Japanese waters, by compiling scientific papers and historical records on marine biota.
The results showed an amazing species diversity of marine life, which accounts for 14.6 %(Note1) of all marine species described from global oceans, and qualifies the Japanese waters as a “biodiversity hot spot.” The number of described species (NDS) was found to make up only 20 % of all species expected to occur in Japanese waters. The study was led by Dr. Katsunori Fujikura, Institute of Biogeosciences, JAMSTEC, in collaboration with about 50 taxonomic experts in Japan.
The findings include:
Evidenced by some comparisons of taxonomic data with those from other oceans, Japanese waters are known to have a rich marine species diversity; yet, this study was the first attempt to comprehensively estimate species richness for all marine organisms in Japanese waters. The results revealed an astonishing diversity of marine life, much higher than the world average.
The findings have been published online on August 2, 2010, in the Public Library of Science One (PLoS One).
Title | : | Marine Biodiversity in Japanese Waters |
Authors | : | Katsunori Fujikura, Dhugal Lindsay, Hiroshi Kitazato, Shuhei Nishida, Yoshihisa Hirayama |
Background
To achieve a sustainable coexistence between human activity and marine organisms, it is crucial to understand biological diversity and ecosystem functioning of marine life as well as correctly assessing the impacts from global environmental change and anthropogenic activity.
Taxonomic inventories of marine life and its diversity were essential, but much work had yet to be done.
At this backdrop, scientists around the world set forth a ten-year project called the “Census of Marine Life (CoML)(*1)” in 2000 to quantitatively estimate diversity, distribution, and abundance of marine species so that the results could serve to a better understanding of marine species richness and ecosystems. The project involves efforts in regional and international levels, setting up 13 National and Regional Implementation Committees (NRICs) in the world to collect marine diversity data. The study presented here is part of such activities for NRICs. The findings along with those from Australia, New Zealand, Mediterranean Sea, Caribbean Ocean, South Africa, Antarctica and U.S have been published in the August 2 issue of PLoS One, as well as in a press release by CoML.
A variety of marine habitats in Japanese waters are considered to contribute to a rich alley of marine species. Surrounded by such waters, marine products have always been one of the popular ingredients for Japanese dishes. Alteration in marine ecosystems induced by global environmental change and human activity will therefore, have significant effects on the Japanese lifestyle. In light of such importance of marine resources, taxonomical, ecological and physiological studies have been actively performed in Japan.
In order to set a baseline for understanding the marine biodiversity in Japanese waters (including territorial waters and the exclusive economic zone), researchers complied information on marine biota and provided a comprehensive analysis.
Outline of method
Marine species in Japanese waters were classified into taxonomic orders, and species richness of each phylum was estimated using three indices - the number of described species (NDS), the number of endemic species (NES) and the number of known introduced species(NIS). There exist many species that were identified but undescribed or have no historical records because of our elementary knowledge of their taxonomy and ecology. The species richness in such cases was estimated as the expected number of species (ENS).
The state of knowledge concerning the taxonomy and ecology of taxa was classified into three categories -known, mostly unknown, unknown-for each phylum, based on the number of described species and their distribution, the number of identification guides and their published years, and the number of taxonomic experts in Japan. More than 50 experts on the taxonomy or ecology of marine organisms collaborated in gathering the species richness information(Table 1).
Results of the census of marine life in Japanese waters
1) Japanese waters as a hotspot of biodiversity: number of described species
The total number of descried species (tNDS) including bacteria to mammals (Table 2), was 33,629. Mollusca had the highest number of species, followed by crustaceans. Among 66 phyla (*2), the 10 phyla with the highest totals of the NDS comprised about 85 % of the tNDS (Figure 1).
According to The Ocean Biogeographic Information System(OBIS)(*11) , the total number of marine species described from the global ocean is estimated at about 230,000(Note2). Given the total volume of the Japanese waters, which makes up only 0.9% of the global ocean, the tNDS (33,629) accounts for 14.6%(Note1) of all marine species around the world.
This globally significant value of species richness qualifies Japanese waters as a biodiversity hotspot, which is considered to be attributed to a variety of marine environments shaped by wide-ranging topography, water depth, water temperature, currents, and climate zone.
2) Number of endemic species
The number of endemic species (NES) in Japanese waters was at least 1,872. Among them, Foraminifera (*3), Pisces and Gastropoda have high values, whereas Annellida had a very low NES and no records were found for Haptophyta(*4) endemic to Japanese waters.
3) Expected number of species (ENS)
The total number of identified but undescribed species(NUS) is estimated at 121,913 (Table 2). The combined total with both the NUS and tNDS (33,629) makes the best estimate of the number of species currently occurring in Japanese waters (155,542). This signifies that only 20% of all estimated species around Japanese waters have been described despite an exceptionally high NUS for Pisces. Gobiidae (or goby) had more than 200 undescribed species.
4) Species introduced to Japanese waters
The number of species introduced to Japanese waters (NIS) was 39, including 11 Mollusca, 10 each of the Annelida and Arthropoda, 3 Chordata, 2 Myxozoa(*5), and 1 of each of the Chlorophyta(*6), Cnidaria, and Heterokontophyta (*7). The presumed primary mechanism of transport is thought to be through hull fouling or in ballast water brought by ships, as well as through import of fisheries resources.
5) State of knowledge
The amount of taxonomical and distribution data available to date differs substantially among taxa (Table 3). The taxa with larger and conspicuous species (e.g. Chordata including fish and Mollusca) had a tendency to be better known and replete with information. On the other hand, some taxa that contain small species, such as Amoebozoa(*8) and Cycliophora(*9), are poorly described and little understood. Difficulties in sample collection and morphological identification due to the organisms being so small, as well as the lack of taxonomic expertise in Japan (and indeed around the world), are the major reasons for our lack of knowledge about these taxa. When compared with the NDS values for representative taxa occurring in Japanese waters published in 1981, NDS values for Amphipoda(Plylum Anthropoda), Hydrozoa(Phylum Cnidaria)(*10), and Asteroidea (Phylum Echinodermata) have increased considerably owing to taxonomic and ecological studies (Table 4).
Discussion and future perspectives
We expect rapid changes in marine biological diversity and ecosystems in Japanese waters including: (1) dining wild fish catches, (2) increase in aquaculture (3) changes in harvesting of specific species , (4) changes in harvested areas, (5) food web changes, (6) shifts in diversity at population, species and genetic levels, (7) species extinction, population extinction, (8) decline in genetic resources (9) changes in species distribution: contraction, expansion, and range shifts, (10) changing traffic patterns of animal migrations, (11) introduction of exotic species, (12)changes in nutrient cycles, and (13)changes in surface primary productivity and carbon fluxes to the seafloor. Yet, our knowledge is still elementary to properly understand benefits (ecosystem services) and marine ecosystem functions. It is essential to know what lives where in the ocean, how many of them occur, and what they do in marine ecosystems. This study provided valuable insights to these questions, while at the same time highlighting quantitative difference in taxonomic and ecological data among taxa. In addition, there are numerous unexplored areas in open waters, especially in the deep sea. Biological investigation in these areas, as well as filling gaps in knowledge among taxa is of great importance.
Databases are a powerful tool to comprehensively analyze changes in biodiversity and ecosystems. However, many databases concerning biodiversity and occurrence of marine species have different schema, requiring urgent measures to establish linkages between them. The Census of Marine Life has developed the Ocean Biogeographical Information System (OBIS) as its main repository of information. Yet, the number of species in Japanese waters recorded in OBIS is still small, illustrating the need for encouraging linkages between Japanese databeses and OBIS, alongside the development of analytical tools that incorporate the environmental background of Japanese waters.
The study set a baseline not only for marine biodiversity and ecosystem studies in Japan, but also for prediction of ecosystem changes, evaluation of biological resources, and environmental impact assessments.
Glossaries
Table 1. Contributors for species diversity estimation
Taxon | Contributor (Institution/Affiliation1) | |
---|---|---|
Archaea | Hiroyuki Yamamoto (JAMSTEC) | |
Bacteria | Yuichi Nogi (JAMSTEC), Hiroyuki Yamamoto (JAMSTEC) | |
Eukarya | Acoelomorpha | Ken-ichi Tajika (Nihon University) |
Ascomycota | Takahiko Nagahama (JAMSTEC) | |
Annelida | Eijiro Nishi (YNU) | |
Arthropoda | Kouki Fukuoka (SNF), Mark J. Grygier (LBM), Nozomu Iwasaki (Kochi University), Tomoyuki Komai (NHMIC), Kazuya Nagasawa (Hiroshima University), Koichiro Nakamura, Susumu Ohtsuka (Hiroshima University), Takashi Onbé (Hiroshima University), Nobuhiro Saito (Suido-sha), Shozo Sawamoto (Tokai University), Michitaka Shimomura (KMNH), Hiroshi Ueda (Kochi University), Toshiyuki Yamaguchi (Chiba University) | |
Basidiomycota | Takahiko Nagahama (JAMSTEC) | |
Brachiopoda | Hiroshi Kajihara (Hokkaido University) | |
Cercozoa | Noritoshi Suzuki (Tohoku University) | |
Chaetognatha | Taichiro Goto (Mie University), Kazunori Kuroda (JSNFRI) | |
Chlorophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Chordata | Naoki Kohno (NMNS), Keiichi Matsuura (NMNS), Tsukasa Murayama (Tokai University), Jun Nishikawa (University of Tokyo), Naonobu Shiga (HJC) | |
Ciliophora | Miwa Nakamachi (TNFRI) | |
Cnidaria | Yukimitsu Imahara (BIK), Shin Kubota (Kyoto University), Keiichi Nomura (KMPC), Hiroyuki Tachikawa (NHMIC), Kensuke Yanagi (NHMIC) | |
Ctenophora | Takushi Horita, Ryo Minemizu (Ryo Minemizu Photo Office) | |
Dicyemida | Hidetaka Furuya (Osaka Univ) | |
Dinophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Echinodermata | Toshihiko Fujita (NMNS) | |
Ectoprocta | Hiroshi Kajihara (Hokkaido University) | |
Entoprocta | Toru Iseto (JAMSTEC) | |
Glaucophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Granuloreticulosa | Shiro Hasegawa (Kumamoto University) | |
Haptophyta | Masanobu Kawachi (NIES) | |
Magnoliopsida | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Metamonada | Naoji Yubuki (UBC) | |
Mollusca | Takashi Okutani (JAMSTEC), Hiroshi Saito (NMNS) | |
Myxozoa | Hiroshi Yokoyama (University of Tokyo) | |
Nemertea | Hiroshi Kajihara (Hokkaido University) | |
Ochrophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Oomycota | Shigeki Inaba (NITE) | |
Orthonecta | Hidetaka Furuya (Osaka Univ) | |
Phoronida | Hiroshi Kajihara (Hokkaido University) | |
Placozoa | Hiroshi Kajihara (Hokkaido University) | |
Platyhelminthes | Ken-ichi Tajika (Nihon University) | |
Porifera | Yuji Ise (University of Tokyo) | |
Radiozoa | Noritoshi Suzuki (Tohoku University) | |
Rhodophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) | |
Streptophyta | Jiro Tanaka (TUMSAT), Hidekazu Suzuki (TUMSAT) |
Table 2. List of species diversity including the number of described species (NDS), the number of undescribed species (NUS), expected number of species (ENS), and the number of introduced species (NIS)
Figure 1. Percent ratio of the number of described species (NDS) in respective phyla
Table 3. Current taxonomic status, Known, Mostly unknown and Unknown, for each Phylum or Division.
Taxonomic status | |||
Known | Mostly unknown | Unknown | |
---|---|---|---|
Acoelomorpha | Acidobacteria | Hemichordata | Acanthocephala |
Bacteroides | Actinobacteria | Heterokontophyta | Amoebozoa |
Cercozoa | Annelida | Kinorhyncha | Apicomplexa |
Chaetognatha | Aquificae | Loricifera | Blastocladiomycota |
Chlorophyta | Arthropoda | Metamonada | Chytridiomycota |
Choanozoa | Ascomycota | Nematoda | Cycliophora |
Chordata | Basidiomycota | Nematomorpha | Glomeromycota |
Ctenophora | Brachiopoda | Nemertea | Heliozoa |
Dicyemida | Cnidaria | Orthonecta | Oomycota |
Echinodermata | Crenarchaeota | Phoronida | Opalozoa |
Ectoprocta/Bryozoa | Cryptophyta | Placozoa | Percolozoa |
Granuloreticulosa | Deinococci | Porifera | Thaumarchaeota |
Haptophyta | Dinomastigota | Proteobacteria | |
Labyrinthulomycota | Echiura | Sipuncula | |
Magnoliopsida | Entoprocta | Tardigrade | |
Mollusca | Euglenophyta | Thermotogae | |
Myxozoa | Euryarchaeota | Verrucomicrobia | |
Radiozoa | Gastrotricha | Zygomycota | |
Rhodophyta | Glaucophyta | ||
Rotifera | Gnathostomulida |
Table 4. Comparison of number of described species in selected taxa between present study and a previous study by Nishimura (1981) [19].
Taxon | NDS1 of previous study [19] | NDS of present study | Increase of NDS2 | ||
Phylum | Class | Order | |||
---|---|---|---|---|---|
Chordata | Pisces | 2700 | 3790 | 1090 | |
Cnidaria | Hydrozoa | 315 | 523 | 208 | |
Chordata | Ascidiacea | 281 | 313 | 32 | |
Echinodermata | Ophiuroidea | ca. 260 | 308 | 48 | |
Echinodermata | Echinoidea | 192 | 161 | -31 | |
Echinodermata | Asteroidea | 167 | 280 | 113 | |
Platyhelminthes | Polycladida | Polycladida | 149 | 150 | 1 |
Porifera | Calcarea | 130 | 130 | 0 | |
Mollusca | Cephalopoda | 125 | 204 | 79 | |
Arthropoda | Pycnogonida | 67 | 153 | 86 | |
Sipuncula | 58 | 47 | -11 | ||
Arthropoda | Crustacea | Amphipoda | 57 | 544 | 487 |
Mollusca | Polyplacophora | 56 | 129 | 73 | |
Brachiopoda | 55 | 73 | 18 | ||
Arthropoda | Crustacea | Stomatopoda | 41 | 56 | 15 |
Cnidaria | Scyphozoa | 38 | 37 | -1 | |
Echiura | 17 | 21 | 4 |
1 Number of described species.
2 Difference between NDS reported in Nishimura (1981) [19] and NDS of the present study.
The number has been changed as follows by the latest research.
Note1 : 13.5%
Note2 : 250,000
(Added August 10, 2012)