Thermal challenge of the Indian shrimp Penaeus indicus

This study investigated short‐term effects of increasing water temperature from 27 to 41°C on survival and feed consumption of Penaeus indicus at three different ages: PL₂₅ (postlarvae 25 days old), PL₅₀ and PL₉₀. For each age group, water temperature was maintained at 27°C in the control, but increased to 32, 35, 38 and 41°C at a rate of 1°C every eight hours. The temperature was then kept stable until the end of the 7‐day experiment. Results showed that increasing water temperature affected both survival and feed consumption of the experimental shrimps (p < .01). Survival was highest at 32 and 35°C ranging from 93.8% to 100%, but significantly reduced to 40.0%–81.6% at 38°C. No shrimp survived the 41°C treatment. PL₂₅ were more tolerant to 38–41°C than PL₅₀ and PL₉₀ in terms of survival. Increasing water temperature had no effects on feed consumption of PL₂₅ (p > .05). For PL₅₀ and PL_90, feed consumption significantly increased at 38 and 41°C (p < .01) and was similar within the range of 27–35°C. This study suggests that P. indicus in tropical areas can tolerate water temperatures of at least 35°C and should be considered for farming during the summer time.     

Critical Thermal Maximum of Juvenile Spotted Seatrout (Cynoscion nebulosus) Reared for Summer Stocking in Texas

The critical thermal maximum of juvenile spotted seatrout (SL range 18–33 mm) was determined using a temperature increase of +0.26°C per hour. The critical thermal maximum (water temperature that was lethal to 50% of the test fish [LT₅₀]) for trial 1 was LT₅₀ = 38.8°C, LT₅₀ = 39.4°C for trial 2, and LT₅₀ = 38.9°C for trial 3. Critical thermal maximums differed significantly (P < 0.05) between trials 2 and 3, whereas trial 1 did not differ among trials. This difference correlated with body size, where fish in trial 2 were significantly larger (P < 0.05) (mean = 27.6 ± 2.0 mm in SL) (mean ± SE) than the fish of trials 1 (mean = 23.1 ± 0.5 mm in SL) and 3 (mean = 21.5 ± 0.7 mm in SL), suggesting positive size dependence in the critical thermal maximum.     

Role of sex steroids in gonadal differentiation of the mussel Choromytilus chorus (Bivalvia Mytilidae) (Molina 1782)

In Chile, the species Choromytilus chorus stands out for its ecological and economic importance. This mussel has a very particular condition in the colour of the gonad, being cream‐yellow colour the male gonad and dark brown the female which is hardly desired by the consumers. In this context, the aim of this research is to determine the role that sex steroids have in gonadal differentiation of the mussel C. chorus. For this, juveniles with sizes 15–22 mm were selected, which were subjected to acute exposure in the form of bath for 60 days to four treatments: T1: dihydrotestosterone (DHT); T2: 17β‐estradiol (E2), T3: fadrozole (F) and T4: DHT‐F (DF), plus a control without chemicals. Each treatment as well as control included three replicates with 90 individuals each. The mussels undergoing treatment with E2 had a sex ratio (male:female) of 0.47 compared to 1:1 in the control group. In contrast, in the groups treated with DHT, F and DF the sex ratio changed to 2.0, 1.60 and 1.70 respectively. In the fertilization trials, all the mussels produced functional gametes, as they were able to generate gametes that were developed to morula, and veliger larva. Nevertheless, it should be noted that the size of oocytes from the group exposed to estradiol (61.12 ± 2.40 μm) was significantly higher than in other groups. These results support the hypothesis that sex steroids would be involved in sexual differentiation of marine bivalves.     

Effects of dietary protein levels on the activity of the digestive enzyme of albino and normal Apostichopus japonicus (Selenka)

We evaluated the effects of different proportions of dietary protein (5%, 10%, 15%, 20%, 25% and 30% protein) on the activity of digestive enzymes of normal and albino Apostichopus japonicus. The experimental diets were fed for 60 days, the optimal conditions for digestive enzyme activity in sea cucumbers were studied. The optimal temperature for protease was 29.3°C and the optimal pH was 1.8. The optimal temperature for amylase was 34.3°C and the optimal pH was 6.7. The optimal temperature for cellulase was 56°C and the optimal pH was 5.9. The activity of intestinal protease increased at first and then decreased as the proportion of dietary protein increased, reaching the maximum when the proportion of protein was 19.7%. The activity of protease in the intestine of normal sea cucumber was significantly lower than that of albino sea cucumber, and the activity of amylase was significantly higher than that of albino sea cucumber. This study is expected to provide a basis for further explaining the ecological difference of albino and normal A. japonicus.     

Dietary supplementation of red alga Pyropia spheroplasts on growth,feed utilization and body composition of sea cucumber,Apostichopus japonicus (Selenka)

A feeding experiment was conducted in a closed recirculating system to evaluate the effects of freeze‐dried spheroplasts prepared from Pyropia yezoensis (Ueda) on feed intake, growth and biochemical composition of sea cucumber, Apostichopus japonicus (Selenka). Pyropea spheroplasts (PS) were prepared through enzymatic treatment to break down the complex mixture of polysaccharides cell walls that might be easier for growth energy partitioning. Sea cucumbers were fed‐formulated diets with 10 (Diet 1), 30 (Diet 2) and 50 g/kg (Diet 3) inclusion level of PS. A diet without PS was used as a control (Diet 4). The experiment was conducted for 6 weeks maintaining water temperature 15 ± 1°C, photoperiod 18:06 hours (D:L). Feed was supplied ad‐libitum at 16.00 h once in a day, and the remaining feed and faeces were removed in the next day. Results showed that the highest growth was observed in the 50 g/kg PS diet compared to other treatments. Total weight gain, mean weight gain, net yield, protein efficiency ratio (PER) and protein gain (%) were significantly higher in the 50 g/kg PS diet (p < .05). A significantly higher percentage of energy was allocated for growth in the 50 g/kg PS diet. The highest specific growth rate and feed conversion efficiency (p < .05) were observed in the higher percentage of PS diet. Both the growth performance and biochemical analysis showed that superior growth was observed with increasing levels of PS in the diet. We infer that PS can be used as a new, cheaper feed ingredient in the formulated diet of A. japonicus.     

Induced breeding of the South American catfish, Rhamdia sapo (C. & V.)

Pituitary suspensions from the characin, Prochilodus platensis, were injected intraperitoneally into male and female Rhamdia sapo at doses between 0.37 and 6 mg dry weight per kg of body weight. Doses from 0.75 to 6.0 mg/kg effectively induced ovulation. The latent period between injection and ovulation for females held at different temperatures (17 to 27°C) decreased with increasing temperature.Stripping of gametes from both sexes, and dry method fertilization were successful and produced viable eggs. The period between ovulation and stripping for the highest hatching rates decreased from about 9 h at 20°C, to 5 h at 24°C. No viable eggs remained in samples obtained after 15 h at 20°C, or 8 h at 24°C. Hatching percentage and the fraction of deformed fry were negatively correlated (r = ?0.75; P < 0.001).     

Effect of temperature on the development of eggs and the daily pattern of spawning of round herring <Emphasis Type="Italic">Etrumeus teres</Emphasis>

Effect of temperature on the development of eggs of round herring Etrumeus teres was experimentally examined to construct a temperature-dependent egg development model. Mature fish were collected in the field and their eggs were artificially fertilized onboard. The eggs were incubated at nine temperatures set between 14.0 and 25.0°C. All eggs at the lowest three temperatures, 14.0°C, 15.0°C, and 16.0°C, ceased development and died at various stages before hatching. Durations required to hatching after fertilization ranged from 38.0 h at 25.0°C to 90.0 h at 17.5°C. The temperature-dependent egg development model, i.e., egg age in hours (y _i,t ) at the ith stage and temperature t (°C), was expressed as: y _i,t  = 4.604 × exp(−0.100 × t −0.129 × i) × i ^2.593. From the application of the model to early-stage eggs collected in the field, it is concluded that round herring starts spawning immediately after sunset and almost completes spawning by midnight. The temperature-dependent egg development model and the daily pattern of spawning presented in this study are essential tools for developing the daily egg production method to estimate the spawning stock biomass.     

Joint effect of temperature,salinity and pH on the percentage fertilization and hatching of Nile tilapia ( Oreochromis niloticus)

Rested upon Box‐Behnken experimental design and response surface method, the joint effect of temperature, salinity and pH on the fertilization and hatching in Nile tilapia was studied under laboratory conditions. Results showed that the linear and quadratic effects of temperature, salinity and pH on fertilization and hatching were all statistically significant (P < 0.01). Interactions between temperature and salinity, and between temperature and pH on fertilization and hatching statistically differed from zero (P < 0.05). Interaction between salinity and pH on hatching was significant (P < 0.05), but nonsignificant on fertilization (P > 0.05). Regressions of fertilization and hatching towards temperature, salinity and pH were established, with the determination coefficient being 99.17% for fertilization and 99.79% for hatching, and could be used for prediction. By utilizing statistical optimization technique, the optimal temperature/salinity/pH combinations were attained: 27.6°C/9.3 ppt/7.5 for fertilization, at which the maximum fertilization was 87.7%, with the desirability being 92.11%; and 27.1°C/9.2 ppt/7.4 for hatching, at which the maximum hatching rate reached 81.2%, with the desirability as high as 96.74%. It could be said that the fertilization and hatching concurrently culminated at the 27.3°C/9.2 ppt/7.4 combination. It can be envisioned that the application of these results derived would give an impetus to the tilapia seed production efficiency and in turn to the development of tilapia husbandry.     

The effects of temperature on respiration of Amur sturgeon,Acipenser schrenckii,at two acclimation temperatures

In order to clarify the respiratory responses strategy of Amur sturgeon Acipenser schrenckii exposed to water temperature changes, respiratory parameters of the fish were studied under two temperature regimes: fish acclimated at 13°C for Group I, temperature was increased to 16°C, 19°C, 22°C and 25°C and then returned stepwise to 22°C, 19°C, 16°C and 13°C; and fish acclimated at 25°C for Group II, the water temperature was reduced in steps to 22°C, 19°C, 16°C and 13°C, subsequently, returned to 16°C, 19°C, 22°C and 25°C. The results showed that the respiratory frequency (f_R), oxygen consumption rate (VO₂) and gill ventilation (V_G) of the fish were directly dependent on the acute temperature in both acclimation groups (p < .05). The initial 25°C VO₂ in Group II was significantly higher than the initial 13°C VO₂ in Group I (p < .05), but was significantly lower than that at 25°C in Group I (p < .05). In Group I, respiratory stroke volume (V_S.R) of fish significantly increased or decreased with the acute temperature increases or decreases, respectively (p < .05); oxygen consumption efficiencies (EO₂) of fish did not significantly show differences when temperature increased to 25°C from 13°C (p > .05), but the EO₂ significantly declined while returning to acclimation temperature (p < .05). In Group II, the V_S.R of the fish did not significantly change with acute temperature fluctuations between 25 and 13°C (p > .05), while the EO₂ increased with acute temperature increases (p < .05). The Q₁₀ values for f_R, VO₂, V_S.R, V_G and EO₂ were 1.53–1.72, 1.92–2.06, 1.07–1.60, 1.78–2.44 and 1.11–1.65 at 13–25°C of temperature interval respectively. Amur sturgeon showed partial metabolic compensation to temperature changes. The study results suggest that the ability of Amur sturgeon to regulate metabolism in response to acute temperature changes makes this species good adaptability in the aquaculture rearing.     

Induction of meiotic gynogenesis in bagrid catfish (Pseudobagrus ussuriensis) with homologous sperm and its confirmation for female homogamety

The bagrid catfish, Pseudobagrus ussuriensis, exhibits significant sexual dimorphism in growth rate and body size with males growing faster than females. Therefore, an all‐male culture can dramatically increase the output and profitability of fishery products. According to the monosex breeding route, super‐male individuals’ acquirement by XY male sex reversal and artificial gynogenesis is the key step. An effective protocol to induce meiotic gynogenesis using homologous sperms has been developed in this study. The most effective UV irradiation for sperm genetic inactivation was found to be at a distance of 20 cm with 66 μW/cm² light intensity for 25 min. Optimal treatment for cold shock was 5 min post‐fertilization at 0‐4°C for 30 min, which gave the best survival rate of 13.65 ± 2.87%. The sex ratio in the meiotic gynogens showed a significant female‐biased deviation (p < .05); thirty meiogynogens and their parents were further analysed using a male‐specific AFLP marker, of which only the male parent produced a male‐specific DNA band of 412 bp. These results indicated the female homogametic XX/XY sex determination system in P. ussuriensis. The optimization of a protocol for the successful induction of meiogynogenesis in the bagrid catfish lays the basis for all‐male production and is useful in ascertaining the genetic sex determination system in this promising aquaculture species.     

Seasonal variations of immune parameters in the coelomic fluid of sea cucumber Apostichopus japonicus cultured in pond

In order to understand the effects of seasonal change on the immunity of sea cucumber Apostichopus japonicus cultured in pond, A. japonicus with body weight of 12.2 ± 4.5 g (sample A) and 32.6 ± 7.1 g (sample B), respectively, were collected monthly and randomly from a typical pond during a year cycle and employed for the evaluation of immunocompetence. Simultaneously, the environmental factors in the pond including water temperature, pH, salinity and dissolved oxygen (DO) were measured using a handheld multiparameter meter. The activities of acid phosphatase (ACP), alkaline phosphatase (ALP), lysozyme (LYZ), phenoloxidase (PO), superoxide dismutase (SOD), catalase (CAT) and myeloperoxidase (MPO) in the coelomic fluid were selected for the evaluation of A. japonicus immunocompetence and determined using biochemical methods. The results showed that in both samples, the activities of all determined enzymes had small values in winter and early spring, and LYZ, CAT and MPO activities also presented small values in summer, suggesting that pond‐cultured A. japonicus underwent immunosuppression twice during a year cycle, and the immunosuppression occurred in winter and early spring was more severe than that occurred in summer. In addition, most of the determined enzymes showed different variations between the two samples, and had significantly negative correlation with protein concentration, which was significantly and negatively correlated with water temperature, revealing that body weight and water temperature might have crucial effects on the immunity of A. japonicus cultured in pond.     

Effects of temperature and photoperiod on the conditioning of the flat oyster (Ostrea edulis L.) in autumn

The production of the flat oyster Ostrea edulis (L.) natural spat in Europe has decreased almost by 60% in the past ten years. Thus, the importance of the production of oyster spat in hatcheries is evident. One of the critical steps in hatchery production is broodstock conditioning, especially difficult in autumn, when gonadal development is in resting period. Conditioning is influence by temperature, photoperiod and nutrition. In this work, the effects of two temperature and three photoperiod regimes on the conditioning of O. edulis were studied for three years by stereological analyses and registering number and dates of spawning and larval yield. Temperature had a positive effect on the gonadal development of O. edulis during conditioning. The percentages of germinal cells in oysters conditioned with a gradient of temperature (14–18°C) were double compared to oysters conditioned at 15°C. Oysters conditioned with longer photoperiods showed higher percentages of germinal cells. There was no interaction between temperature and photoperiod. Spawning was observed in the oysters treated with daylight (8–16 h) ten weeks from the beginning of conditioning. Flat oysters conditioned with 8 h and 8–12 h of daylight delayed the first spawning for a month. Total larval production was higher in the oysters treated with the longest daylight gradient. Gonadal and gametogenic development was a non‐synchronic process and the spawning extended for around two months. A protocol for flat oyster broodstock conditioning in autumn by using both a gradient of temperature (14–18°C) and daylight (8–16 h) is proposed.     

Influence of photoperiod and temperature manipulation on gonadal development and spawning in Caspian roach (Rutilus rutilus caspicus): Implications for artificial propagation

Caspian roach (Rutilus rutilus caspicus), a spring spawning teleost, were subjected to various photoperiod and temperature regimes to study the feasibility of shifting the timing of spawning for artificial propagation purposes. A total of 650 female reproductively mature R. rutilus caspicus were subjected to different photoperiod and temperature regimes including four light regimes (natural light (NL), 16 hr of light (L):8 hr of darkness (D), 9L:15D, 11L:13D), each affected by three temperature regimes (14, 20 and 24°C) for 70 days. Five fish per tank were randomly sampled on Feb. 10, Feb. 20, March 28, April 15 and April 30 (natural spawning time). Ovarian tissue sections were studied using light microscope and transmission electron microscope (TEM). The levels of 17‐β estradiol (E2) and 17α‐hydroxyprogesterone (OHP) were also measured in the serum samples. In late winter (March 28th), the gonadal maturation and spawning were accelerated in fish treated with the long day length (16L/8D) and warm temperature (20°C). While, the maturation of oocytes and spawning delayed in fish exposed to low temperature (14°C) and short day length (9L/15D and 11L/13D). Photoperiod seems to play a more important role in the ovarian development of the R. rutilus caspicus compared to temperature; since even among the fish treated with the lowest temperature (14°C), those exposed to a longer day length (16L/8D), matured and spawned earlier than the others. Considering that the earliest spawning occurred in R. rutilus caspicus treated with 16L/8D at 20°C and the latest spawning occurred in fish exposed to low temperature and short photoperiod, it can be concluded that temperature and photoperiod play an important role in accelerating oocyte maturation and spawning.     

Antioxidant Properties of Scomber japonicus Hydrolysates Prepared by Enzymatic Hydrolysis

The antioxidant properties of the Pacific chub mackerel (Scomber japonicus) muscle protein hydrolysates prepared by enzymatic hydrolysis were investigated. After enzyme hydrolysis at 50°C for 60 min, more than 80% of the S. japonicus muscle protein was hydrolyzed. The highest 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (71.69%) occurred in whole muscle protein hydrolysates treated at 50°C for 30 min with Protamex, and the highest 2,2?-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS) radical-scavenging activity (95.39%) was observed in white muscle protein hydrolysates treated at 50°C for 30 min with Neutrase. The highest superoxide dismutase (SOD)-like activity (32.84%) was recorded in white muscle protein hydrolysates treated at 50°C for 120 min with Protamex. Changes in the molecular weight distribution of S. japonicus muscle proteins after enzymatic hydrolysis were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A robust and a convenient enzyme hydrolysis technique for obtaining S. japonicus muscle protein hydrolysates with useful biological activities, within a short time (<2 h) is proposed.     

Metabolic measurements and parameter estimations for bioenergetics modelling of Pacific Chub Mackerel Scomber japonicus

As a crucial step in developing a bioenergetics model for Pacific Chub Mackerel Scomber japonicus (hereafter chub mackerel), parameters related to metabolism, the largest dissipation term in bioenergetics modelling, were estimated. Swimming energetics and metabolic data for nine chub mackerel were collected at 14°C, a low temperature within the typical thermal range of this species, using variable‐speed swim‐tunnel respirometry. These new data were combined with previous speed‐dependent metabolic data at 18 and 24°C and single‐speed (1 fork length per second: FL/s) metabolic data at 15 and 20°C to estimate respiration parameters for model development. Based on the combined data, the optimal swimming speed (the swimming speed with the minimum cost of transport, U_opt) was 42.5 cm/s (1.5–3.0 FL/s or 2.1 ± 0.4 FL/s) and showed no significant dependence on temperature or fish size. The daily mass‐specific oxygen consumption rate (R, g O₂ g fish^?1 day^?1) was expressed as a function of fish mass (W), temperature (T) and swimming speed (U): R = 0.0103W^?0.490 e^(0.0457T) e^(0.0235U). Compared to other small pelagic fishes such as Pacific Herring Clupea harengus pallasii, Pacific Sardine Sardinops sagax and various anchovy species, chub mackerel respiration showed a lower dependence on fish mass, temperature and swimming speed, suggesting a greater swimming ability and lower sensitivity to environmental temperature variation.     

Effect of two temperatures on yield and increase in cranial skeletal abnormalities during early development of palm ruff,Seriolella violacea (Guichenot 1848)

The present study evaluates the effect of two temperatures, 14°C (T14) and 18°C (T18), on yield and the presence of cranial abnormalities during early development in north palm ruff (Seriolella violacea). Different time indices – days post‐hatching (DPH), degree‐days (D°) and effective degree‐days (D°_eff) – were used to analyse growth during cultivation. Several ontogenetic events were achieved in less time during cultivation at 18°C. Additionally, a larger total length and final weight, as well as a higher survival rate, were achieved after 80 days of culture at higher temperatures (T18 = 55.5 ± 1.5 mm; 2.87 ± 0.21 g; 1.80 ± 0.18% and T14 = 24.3 ± 2.2 mm; 0.26 ± 0.08 g; 1.33 ± 0.12%). D° and D°_eff were valid as independent temperature indices for predicting the growth response of S. violacea against thermal variations. The frequencies of cranial skeletal abnormalities (mouth and opercular complex) were evaluated in the pre‐flexion, flexion, post‐flexion and juvenile stages. However, the frequency of cranial skeletal abnormalities at the end of this study was not significantly influenced (P > 0.05) by temperature, and values below 21% were recorded in both treatments. These results can be of practical use for optimizing culture conditions to maximize the yield and quality of S. violacea juveniles.     

The induction of Hsp70 synthesis by non‐lethal heat shock confers thermotolerance and resistance to lethal ammonia stress in the common carp,Cyprinus carpio (Linn)

Exposure to heat‐shock protein (Hsp) stimulating factors induces Hsp accumulation and confers tolerance to lethal ammonia stress on the common carp Cyprinus carpio. This study investigated whether a non‐lethal heat shock bestowed similar protective effects against ammonia and induced thermotolerance, both thought to be rendered by increased amounts of Hsps. The 30‐min lethal temperature (30 min LHT) and 1‐h lethal ammonia concentration (1 h LCT) for this species occurred at 41°C and 14.2 mg/L NH₃ respectively. Heating juvenile carp (5 cm) from 28°C to 32, 34 and 38°C, with a subsequent 8‐h recovery period augmented tolerance to lethal heat and ammonia perturbation by two to threefold as compared with animals held at 28°C. Protection occurred in conjunction with Hsp70 accumulation in gills, substantiating the role of this Hsp in enhancing the stress tolerance of common carp.     

High light might alleviate inhibitory effects of high temperature on growth and physiological parameters of Ulva prolifera

In order to explore the effects of high temperature (HT) and light on the physiological and biochemical aspects of macroalga Ulva prolifera, we cultured this species under two temperatures (20°C: low temperature, LT; 30°C: HT) and two light intensities (80 μmol m^?2 s^?1: low light, LL; 400 μmol m^?2 s^?1: high light, HL) for 5 days. It was found that (a) compared to 20°C, the chlorophyll a (Chl a) content was increased at 30°C under LL conditions, the relative growth rate (RGR) was significantly decreased at 30°C; (b) compared to LL treatment, HL significantly increased RGR but significantly decreased Chl a content; (c) LL‐grown U. prolifera at 30°C showed the highest photosynthetic oxygen evolution rate; however, there were no significant effects of temperature and light on the relative electron transport rate; (d) superoxide dismutase activity was significantly decreased by HL, but no significant effects of temperature were observed; and (e) compared to LL, HL significantly increased the soluble sugar content at 20°C, but significantly reduced at 30°C. These results showed that the inhibitory effects of HT can be offset by HL intensity.     

In vitro storage of fish oocytes: effect of storage temperature,media conditions and storage duration on fertilization and larval hatchability of Indian major carp,rohu (Labeo rohita)

The viability of matured oocytes stored in vitro were assessed using carp ovarian fluid (OF) and artificial carp ovarian fluid (ACOF) under different temperature regimes (4, 24, 26, 28 and 30°C) for different storage durations (0, 60, 120, 150 and 180 min). Significantly higher fertilization (74%) was achieved when the oocytes were stored using ACOF and 65% in OF after 180 min at 28°C. Similarly the hatching rates of larvae were significantly higher in the ACOF and OF, that is, 64% and 47%, respectively, after 180 min of storage. The oocytes kept in the storage containers with ACOF having 65% moisture level showed a significantly higher fertilization rate than the 59% moisture level. This study demonstrated that unfertilized matured oocytes (eggs) of rohu can be stored in vitro for 180 min without compromising the viability (fertilization and hatching) to a great extent in OF and ACOF.     

Effect of temperature and relative humidity on the tolerance of the Japanese clam, Ruditapes philippinarum (Adams & Reeve), to air exposure

Laboratory studies showed that higher relative humidity (RH) and lower air temperature increase the tolerance of the Japanese clam, Ruditapes philippinarum (Adams & Reeve), to exposure. Aerial respiration of the clam was also measured. At high RH, the exposure time which gave 50% survival (LT₅₀) was 1.97 and 1.75 times longer than in low RH at air temperatures of 15 and 25 °C, respectively. At 15 °C, all clams previously acclimatized at 15 °C survived for 58 h at low RH and 102 h at high RH. These differences can potentially be exploited to improve the shipment of clams. The aerial respiration experiment showed that the increase of the oxygen consumption rate at 25 °C was greater than that at 15 °C, following an increase in exposure time. The aerial respiration rates of the clams were ≈ 41.6% and 50.0% of those in water at 25 and 15 °C, respectively. The survival of the clams in air was dependent on aerobic rather than anaerobic respiration.