Red Abalones Research Articles

Sublethal effects of hypoxia in the abalone ( Haliotis rufescens) as measured by in vivo31P NMR spectroscopy

1. 1. Effects of hypoxia were investigated in red abalones ( Haliotis rufescens) using a flow-through exposure system and in vivo 31P NMR spectroscopy. 2. 2. Following seawater acclimation, abalones were exposed to air for 1 hr, then seawater for 2.5 hr to check recovery; parallel controls were performed without air exposure. 3. 3. In foot muscle, hypoxia produced a decrease in phosphoarginine concentration and intracellular pH, an increase in inorganic monophosphate concentration, and no change in that of ATP; upon resubmergence, all effects generally recovered. 4. 4. The changes induced by hypoxia during normal tidal changes are consistent with the blockage of mitochondrial oxidative phosphorylation. 5. 5. Use of in vivo NMR allows measurement of the biochemical effects of natural stress factors in live, intact aquatic organisms in the laboratory.

Monitoring of metabolic responses of intact Haliotis (abalones) under salinity stress by 31P surface probe localized NMR.

Surface probe localized 31P NMR spectroscopy was employed to record the metabolic responses of the foot of intact Haliotis cracherodii and H. rufescens (black and red abalones) under hyper- and hypoosmotic stresses. Use of the surface probe allowed spectral localization on the foot of intact abalones, facilitated monitoring of different sizes of animals, and minimized constraints on aquatic chamber design normally imposed by homogeneous-field probes. Generally, hyperosmotic stress (51%) elicited more rapid changes of phosphate metabolites than hypoosmotic stress (17%). As with the well-studied hypoxic stress in intact mammalian and excised molluscan tissue, both salinity treatments caused drops in the phosphagen and increases in inorganic phosphate levels. However, osmotic stress was distinct from hypoxic stress in that intracellular pH did not change and nucleotide triphosphate (NTP) concentrations dropped immediately. Although these findings are preliminary, they demonstrate the utility of the surface probe approach for studies of environmental stress in intact marine invertebrates.

米国産アワビの移植と発生および成長について

Red abalones Haliotis rufescens which in the coastal waters of California were transplanted to Mohne Inlet, Miyagi pref. and the investigations concerning their growth and early development were carried out. The results are summarized as follows. 1. Growth and gonadal maturation of the transplanted red abalone, H. rufescens were vigorous at a water temperature within the range of 14-20°C. The spawning season of this species in Mohne Inlet was during late June and middle July. 2. With temperature stimulation measures the writer succeeded in the induction of spawning artificially. The early development of this species was almost the same as the Japanese abalones except in shell color. Beyond shell lengths of about one centimeter, the young shells grew and metamorphosed into the characteristic form of this species. 3. The growth rate of the youngs of the red abalone was almost the same as that of the Japanese abalone, H. discus hannai. However, in the case of the red abalone, the spawning season was initiated earlier than that of the Japanese abalone. Therefore, considerable good results of rearing may be expected with the introduc-tion of this species.