Marine Biology

, Volume 148, Issue 3, pp 551–558 | Cite as

Establishment of the photosymbiosis in the early ontogeny of three giant clams

  • E. HiroseEmail author
  • K. Iwai
  • T. Maruyama
Research Article


Distribution and morphology of zooxanthellae were investigated histologically and ultrastructurally in veligers and juveniles of three giant clam species, Tridacna crocea, T. derassa, and T. squamosa. No zooxanthellal cells were associated with gametes. In veliger larvae, zooxanthellae were ingested and digested in the stomach. Within several days after metamorphosis from veliger to a juvenile clam, the zooxanthellal tube, in which zooxanthellae were packed, elongated from the stomach toward the mantle. Zooxanthellae in the tube appeared in a line, and we designated the appearance of the lined zooxanthellae in the mantle of juvenile clams as the first sign of the establishment of symbiosis. The zooxanthellal tubular system developed as the clams grew, particularly in the mantle margin, and then hypertrophied siphonal tissue formed. In zooxanthellal tubes, zooxanthellae usually had intact ultrastructures suggesting that they were photosynthetically active, while the stomach always contained degraded zooxanthellae that were probably discharged from the zooxanthellal tube. Giant clams probably digest zooxanthellae directly, and ingest the secreted photosynthates from zooxanthellae. There may be a selection mechanism to discharge unhealthy zooxanthellae from the mantle into the stomach. In addition to zooxanthellae, digested diatoms and other unidentified digested materials in the stomach suggest that filter-feeding also contributes to giant clam nutrition.


Trench Shell Length Hemocyte Glycidyl Ether Giant Clam 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The present study was supported by the twenty-first century COE program of the University of the Ryukyus. We are indebted to Dr. Yasunori Saito (Shimoda Marine Research Center, University of Tsukuba) for providing the facilities for electron microscopy and Dr. Hideyuki Yamashiro (Meio University) for his advice on the decalcification of specimens. Dr. James D. Reimer (JAMSTEC) was acknowledged for his valuable comments and correcting the English. This report includes the contribution form Shimoda Marine Research Center (# 713).


  1. Carlos AA, Baillie BK, Maruyama T (2000) Diversity of dinoflagellate symbionts (zooxanthellae) in a host individual Mar Ecol Prog Ser 195:93–100CrossRefGoogle Scholar
  2. Fankboner PV (1971) Intracellular digestion of symbiotic zooxanthellae by host amoebocytes in giant clams (Bivalvia: Tridacnidae), with a note on the nutritional role of the hypertrophied siphonal epidermis Biol Bull 141:222–234CrossRefGoogle Scholar
  3. Farmer MA, Fitt WK, Trench RK (2001) Morphology of the symbiosis between Corculum cardissa (Mollusca: Bivalvia) and Symbiodinium corculorum (Dinophyceae) Biol Bull 200:336–343CrossRefGoogle Scholar
  4. Fitt WK, Trench RK (1981) Spawning, development, and aquisition of zooxanthellae by Tridacna squamosa (Mollusca, Bivalvia) Biol Bull 161:213–235CrossRefGoogle Scholar
  5. Ishikura M, Adachi K, Maruyama T (1999) Zooxanthellae release glucose in the tissue of a giant clam, Tridacna crocea Mar Biol 133:665–673CrossRefGoogle Scholar
  6. Jameson SC (1976) Early life history of the giant clams Tridacna crocea Lamark, Tridacna maxima (Röding), Hippopus hippopus (Linnaeus) Pac Sci 30:219–233Google Scholar
  7. Kawaguti S (1966) Electron microscopy on the mantle of the giant clam with special references to zooxanthellae and iridophores Biol J Okayama Univ 12:81–92Google Scholar
  8. Klumpp DW, Bayne BL, Hawkins AJS (1992) Nutrition of the giant clam Tridacna gigas (L.). I. Contribution of filter feeding and photosyhthate to respiration and growth J Exp Mar Biol Ecol 155:105–122CrossRefGoogle Scholar
  9. Klumpp DW, Lucas JS (1994) Nutritional ecology of the giant clams Tridacna teborea and T. derasa from Tonga: influence of light on filter-feeding and photosynthesis Mar Ecol Prog Ser 107:147–156CrossRefGoogle Scholar
  10. LaBarbera M (1975) Larval and post larval developments of the giant clams Tridacna maxima and Tridacna squamosa (Bivalvia: Tridacnidae) Malacologia 15:69–79Google Scholar
  11. Mansour K (1946a) Communication between the dorsal edge of the mantle and the stomach of Tridacna Nature 157:844CrossRefGoogle Scholar
  12. Mansour K (1946b) Source and fate of the zooxznthellae of the visceral mass of Tridacna elongata Nature 158:130CrossRefGoogle Scholar
  13. Maruyama T, Heslinga GA (1997) Fecal discharge of zooxanthellae in the giant clam Tridacna derasa, with reference to their in situ growth rate Mar Biol 127:473–477CrossRefGoogle Scholar
  14. Norton JH, Shepherd MA, Long HM, Fitt WK (1992) The zooxanthellal tubular system in the giant clam Biol Bull 183:503–506CrossRefGoogle Scholar
  15. Trench RK, Wethey DS, Porter JW (1981) Observation on the symbiosis with zooxanthellae among the Tridacnidae (Mollusca, Bivalvia) Biol Bull 161:180–198CrossRefGoogle Scholar
  16. Yonge CM (1936) Mode of life, feeding, digestion and symbiosis with zooxanthellae in the Tridacnidae Sci Rep Gr Barrier Reef Exped (1928–29), Brit Mus (Nat Hist) 1:283–321Google Scholar
  17. Yonge CM (1953) Mantle chambers and water circulation in the Tridacnidae (Mollusca) Proc R Soc Lond 123:551–561Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, NishiharaOkinawaJapan
  2. 2.Yaeyama Branch LaboratoryOkinawa Fisheries Experiment StationIshigakiJapan
  3. 3.Extremobiosphere Research Center Japan Agency for Marine-Earth Science and Technology (JAMSTEC)YokosukaJapan

Personalised recommendations