We investigated the effect of temperature on disk abalone Haliotis (Nordotis) discus discus hemolymph CO_2 solubility coefficient (αco_2) and the apparent dissociation constant of carbonic acid (pKapp). The disk abalone hemolymph was equilibrated with a standard CO_2 gas mixture between 10℃ and 20℃, to obtain expressions for αco_2 and pKapp as a function of temperature. The relationship between αco_2 and temperature (T) is expressed as follows： αco_2 = 74.005 - 1.2936 • T - 0.00944 • T^2. And the relationship between pKapp and temperature expressed as follows： pKapp = 6.4675 - 0.08682 • T + 0.003996 • T^2. In these equations, the parameter units are ℃ for T and µM/L/torr for αco_2. The non-bicarbonate buffer values (ꞵ_NB), obtained as a regression coefficient relating pH and [HCO_3^–], were 2.5 Slykes at 10℃, 2.2 Slykes at 15℃, and 3.4 Slykes at 20℃. These equations enable estimation of hemolymph αco_2 and pKapp between temperatures of 10℃ and 20℃.

To induce breeding of the freshwater pufferfish Colomesus asellus, artificial maturation by hormone injection (hCG, 10 IU per gram) and insemination were performed, and subsequent development observed. The rearing environment for the parental fish was freshwater, maintained at 26.0 ± 1.5 ℃ under L12：D12 lighting cycle. Two hormone treatments were applied, one month apart, to two females and four males, ovulation being confirmed 47 hours after the second treatment. Three hundred and sixty-three and 548 eggs with a mean diameter of 1.11 mm (n = 20) were collected from the two females, 334 (92.0 %) and 395 (72.1 %) being fertilized, respectively. The larvae and juveniles were fed with S-type Brachionus sp. fortified initially with freshwater chlorella, followed by Artemia larvae and Chironomid sp. larvae. The pufferfish were reared in a salinity of 7 ‰ for 24 days after hatching, the water then being gradually changed to freshwater over the following 10 days. Two individuals survived for 225 days after hatching, growing to average standard and total lengths of 29.24 mm and 38.72 mm, respectively. The Gonperz growth formulae were as follows：SL：Lt = 29.4075×exp (-exp (-0.02301(t-39.1213))) TL：Lt = 38.51177×exp (-exp (-0.023253(t-41.25841))) Further investigations of rearing conditions, such as salinity, are required to improve the breeding techniques for this species.

On board research were carried out for investigate the quality of fishing boat under the circumstances, which are observed experimentally in ordinary use on the seas. The present research was prepared in the ordinary operation of maintenances in dock. As the results, it was revealed that fuel consumption was reduced remarkably by cleaning bottom of ship hull, propeller and rudder. And in the condition of foul of ship bottom before cleaning, reducing the rotation speed of the main engine capable of largely improving a fuel efficiency, in comparison to the rate of decrease in ship speed.

Viral edema of carp is caused by Carp edema virus and is a major carp disease listed on the WOAH list of emerging infectious diseases. However, an effective experimental infection method that can control virus copy number has not been established. In this study, we compared three experimental infection methods：immersion infection using gill suspensions from diseased fish (immersion method), infection by rearing water from diseased fish (rearing water method) and co-infection method. Cumulative mortality in the immersion groups ranged from 40 to 60%, while that in the rearing water infected and co-infected groups ranged from 80 to 100%. The rearing water method can be used to control the viral DNA copy number and to perform experimental infections when frozen storage is possible. Thus, we performed the same experimental infection using frozen rearing water and found no disease or mortality, indicating that stable experimental infection using the rearing water method is difficult. The immersion method has a lower mortality rate than the other two methods, and it requires a large amount of gill tissue because of the low number of virus DNA copies that can be obtained from the gill tissue. However, it is possible to control the number of virus DNA copies and to preserve the gill tissue suspension by freezing. Therefore, the immersion method was considered the most suitable for stable experimental infection under the same conditions,