Effects of salinity and body mass on oxygen consumption and ammonia excretion of mudskipper Boleophthalmus pectinirostris

We evaluated the effects of salinity and body mass on the oxygen consumption rate and ammonia excretion rate of mudskipper Boleophthalmus pectinirostris under laboratory conditions. Salinity and body mass had highly significant effects on the oxygen consumption rate （Ro） and ammonia excretion rate （RN） （P〈0.01）. The interactive effects between salinity and body mass on Ro and RN were insignificant （P〉0.05） and highly significant （P〈0.01）, respectively. Ro and RN of B. pectinirostris decreased significantly as the individual body mass increased. The relationship between Ro and body mass was represented by Ro=aWb （R^2=0.956, P〈0.01）. The relationship between RN and the body mass ofB. pectinirostris was represented by RN-cW^at （R^2=0.966, P〈0.01）. The Ro/RN （O：N） ratios increased significantly as the salinity increased from 12 to 27, but decreased as salinity increased from 27 to 32. The atomic O：N ratios were significantly higher at 27 than at other salinity levels. The average O：N ratio was 25.25. Lipid and carbohydrate were the primary energy sources and protein was the secondary energy significantly higher at 27 than at other salinity levels B, pectinirostris is 27. source within the salinity range 12 32. Ro andRN were Our results suggest that the optimum salinity level for B. pectinirostris is 27.

Tolerance, Oxygen Consumption and Ammonia Excretion of Ophiopholis sarsii vadicola in Different Temperatures and Salinities

There are more than 2000 species of brittle stars in the world. For most of them, many scientific questions including basic characteristics of eco-physiology are still unknown. In the present study, Ophiopholis sarsii vadicola acclimated at 15 ℃, salinity 31, were assessed for temperature monia excretion were studied at different temperatures （5, 10, and salinity tolerance. Its oxygen consumption and am- 15, 20, 25℃） and salinities （25, 30, 35）. O. sarsii vadi- cola could tolerate 0-24℃ and no brittle star was dead in the salinity range of 19-48 in the experimental situation. Two-way ANOVA showed that the oxygen consumption and ammonia excretion normalized with both dry mass and wet mass, Q10, which is used to describe the temperature sensitivity of respiration, and moisture content were significantly affected by temperature and salinity, and the combined effects of the two factors were significant. Stepwise multiple regression analysis revealed that logarithmic oxygen consumption and ammonia excretion showed a significant positive relationship with logarithmic temperature and salinity. The logarithmic moisture content of the brittle stars showed an inverse relationship with logarithmic salinity, but a positive relationship with logarithmic temperature. This suggests that the tolerance of temperature and salinity of brittle stars is closely related to their living environment, and that the effects of temperature on oxygen consumption are more significant at higher salinity, and that the ammonia excretion is less affected by salinity at lower temperatures.

EFFECTS OF TEMPERATURE ON OXYGEN CONSUMPTION AND AMMONIA EXCRETION BY SOLENAIA OLEIVORA

The effects of water temperature on oxygen consumption rate and ammonia excretion rate of Solenaia oleivora were studied in the laboratory. The results showed that, under controlled conditions and ambient temperatures 15—30℃, the relationship between oxygen consumption rate (O) [mg/h] and dry weight of soft tissue (W) [g] can be represented by an allometric equation O=aW b, while the relationship between ammonia excretion rate (N) [μg/h] and dry weight of soft tissue (W) [g] follows also an allometric equation N=cW b. It is indicated that both metabolic rates are correlated positively with water temperature. High temperature can reduce the level of protein metabolism. The linear regression among oxygen consumption rate (O), temperature (T) and dry weight of soft tissue (W) can be described by the equation O=-0.6513+0.0532T+0.1073W, and for ammonia this relation is N=32.1626-1.0566T+1.3222W, the multiple relation coefficient was 0.9642 and 0.8921, respectively.

Effects of flow velocity on water quality and ammonia excretion in recirculating aquaculture system culturing juvenile largemouth bass(Micropterus salmoides)

Flow velocity plays an important role in recirculating aquaculture systems(RAS)and the growing practice of culturing juvenile largemouth bass(Micropterus salmoides).In this study,the effects of flow velocity on the water quality as well as the ammonia excretion were discussed from the perspective of actual production,and a polynomial model of ammonia nitrogen excretion was established,using the juvenile largemouth bass.Results showed that the range of ammonia nitrogen and nitrite nitrogen decreased with flow velocity increasing,while the number and volume share of large particles increased.According to the polynomial model,compared with the medium flow velocity(11 cm/s,2.45 body length(bl)/s),the ammonia excretion of juvenile largemouth bass at high(18 cm/s,4.00 bl/s),and low(4 cm/s,0.90 bl/s)flow velocity changed faster with time,and the excretion rate peaked at the 6th hour after feeding,earlier than that under medium flow velocity.Therefore,it is suggested to increase the flow velocity at the 5th hour after feeding and then decreased it at the 10th hour,to ensure better water quality in RAS culturing juvenile largemouth bass.

Effect of Fouling on Feeding, Oxygen Consumption and Waste Excretion of Pearl Oyster Pinctada martensii in Daya Bay Cultivation

Biofouling is a particular problem in the pearl oyster culture. It may reduce the growth and survival rates of the cultured species. Foulers are often themselves filter feeders, and are therefore potential competitors for food resource with the cultured species. Fouling organisms may also reduce the oxygen supply. A study was conducted to measure the impact of foulers on feeding oxygen consumption, and waste excretion. POM, ammonia, phosphate and oxygen concentration were measured in various treatments （cultured species, foulers）. This study showed that fouling organisms had significant effect on food uptake, oxygen consumption and waste excretion. The clearance rate, ammonia and phosphate release rate, oxygen consumption rate of the fouled pearl oyster were greater than those of the clean pearl oysters. Other foulers that settled on cages or buoys also contributed much to phytoplankton depletion, oxygen consumption and concentration increase of ammonia and phosphate in water. Therefore, this study showed us that foulers were important competitors in the pearl oyster cultivation of Daya Bay in November 2005.

Metabolism of polychaete Neanthes japonica Izuka: relations to temperature,salinity and body weight

Polychaete Neanthes japonica is a species geographically specific in China and Japan with important scientific implication and commercial value. In this study, the relations of body weight, salinity and temperature to oxygen consumption and ammonia excretion of N. japonica were determined. Three different groups in body weight （large： 2.34±0.36 g, middle： 1.50±0.21 g and small： 0.62±0.12 g） were set for all experiments. Results show that the body weight is negatively related to the rates of oxygen consumption and ammonia excretion; and the relationship is significant. The oxygen consumption and ammonia excretion at 24℃ decreased at salinity from 5 to 30 and increased above 30, indicating that both lower and higher salinity are adverse and certain degree of salinity stress is necessary for enhancing the energy demand. At salinity 30, rising temperature from 18℃ to 30℃, the oxygen consumption increased before 27℃ and then decreased. However, the relation of ammonia excretion and temperature seems more complex. Two-way ANOVA shows that salinity, temperature and body weight all have a significant effect on the oxygen consumption and ammonia excretion of the worm. Moreover, interaction between salinity/temperature and body weight is also significant. O：N （oxygen/nitrogen） ratio varies greatly in this case from 5.97 to 463.22, indicating that N. japonica can regulate the type of metabolic substrate against environment changes.

The Research Development of Respiratory Metabolism for Living Beings of Fishery Resources

[Objective]To describe the research development of respiratory metabolism for living beings of fishery resources home and abroad so as to provide reference for fishery production and management. [Method]Investigate research methods of respiratory metabolism about fish,shrimp, crab,shells and other living beings and analyze factors affecting their oxygen consumption rates and ammonia excretion rates according to research results of respiratory metabolism for living beings of fishery resources home and abroad. [Result] Respiratory metabolism is one of the important contents of bioenergetics research,an important part of energy balance research. It reflects not only the physiological status of living beings,but al- so the influence of environment condition on their physiological activities. Factors affecting respiratory metabolism are divided into biological factors and non-biological factors. By researching factors such as weight,temperature,activities,circadian rhythm,ingestion,Oxygen partial pressure and so on,we can evaluate respiratory metabolism of living beings of fishery resources. [Conclusion]Investigating from the individual physiology and e- cology to group physiology and ecology,the research provides data support for enhancement and releasing of sea ranch.