Acclimation Procedure Research Articles

Acclimation procedure: a neglected good management practice to mitigate post-transport stress in fish

Acclimation procedure: a neglected good management practice to mitigate post-transport stress in fish

Housing conditions modify seasonal changes in basal metabolism and body mass of the Siberian hamster, Phodopus sungorus

Proper housing conditions are important aspects of animal welfare. Animals housed in enriched environments show less stereotypic behaviours than animals kept in barren cages. However, different types of cage enrichment may affect the results of experimental studies and hinder comparative analyses of animal physiology and behaviour. We investigated whether access to a running wheel, availability of nesting material, and pair housing affect basal metabolic rate (BMR) of Siberian hamsters (Phodopus sungorus) under various acclimation conditions. We used 70 adult hamsters (35 males and 35 females) divided into five groups housed under different cage conditions. All individuals experienced the same acclimation procedure: first a winter (L8:D16) then a summer (L16:D8) photoperiod, at air temperatures of first 20 °C then 7 °C under both photoperiods. We found that nesting material and pair housing did not affect hamster BMR, while access to a running wheel increased BMR and body mass regardless of photoperiod and ambient temperature. Thus, we suggest that cage enrichment should be applied with caution, especially in studies on energetics or thermoregulation, particularly in seasonal animals.

Introduction of adult cats to indirect calorimetry respiration chambers causes increased energy expenditure and respiratory quotient that decrease following acclimation.

To replicate a previously defined behavioral procedure to acclimate adult cats to temporary restriction in indirect calorimetry chambers and measure energy expenditure and respiratory quotient changes during acclimation. 8 healthy adult cats (4 spayed females, and 4 neutered males; mean ± SEM age, 2.5 ± 1.5 years; mean body weight, 4.8 ± 1.8 kg). Cats underwent a 13-week incremental acclimation procedure whereby cats were acclimated to the chambers in their home environment (weeks 1 to 3), to the study room (weeks 4 to 6), and to increasing lengths of restriction within their home environment (weeks 7 to 8) and the chambers (weeks 9 to 13). Cat stress score, respiratory rate, fearfulness (assessed with a novel object test), energy expenditure, and respiratory quotient were measured. Data were analyzed by use of a repeated-measures mixed model. Stress, based on cat stress scores, fearfulness, and respiration, peaked at weeks 4, 9, and 10 but returned to baseline levels by week 11. Energy expenditure and respiratory quotient peaked at weeks 10 and 11, respectively, but were reduced significantly by weeks 11 and 13, respectively. All cats returned to baseline by the end of the study and were deemed fully acclimated. Changes in perceived stress level, energy expenditure, and respiratory quotient at various stages of the acclimation procedure suggest that stress should be considered a significant variable in energy balance measurements when indirect calorimetry is used in cats. An incremental acclimation procedure should therefore be used to prepare cats for the temporary space restriction necessary for indirect calorimetry studies.

50 Effects of acclimation on cattle response to humans while being handled

Abstract The objective of this study was to evaluate the impact of previous human interaction on the behavior of beef cows while they are being handled. To achieve this, 84 F-1 Angus x Brahman cows were randomly assigned to one of two human interaction treatments. The positive human-animal interaction group (P) was subjected to daily contact with a herdsman (on foot) for 15 minutes and was fed supplement by the herdsman. The control group (N) was checked daily and fed from a vehicle, with no direct human interaction. Each acclimation procedure was replicated in 2 pastures/herds (n = 16 to 26 cows in each herd). During routine processing times for these herds (d 0, 256, and 317), herds were gathered from their pastures and temperament was assessed. Chute and alley scores were assigned to individual animals by the same trained observer and ranged from 1 (calm) to 5 (aggressive). Chute exit velocity was also measured. Temperament variables were evaluated with ANOVA as a split plot with acclimation procedure in the whole plots and pasture as the whole-plot experimental unit, and processing time in the split plot. Neither human interaction (P = 0.99) nor time (P = 0.13) affected chute exit velocity. Chute score increased through time (P = 0.01) but was not affected by human interaction (P = 0.70). Alley score was not affected by human interaction (P = 0.32) or time (P = 0.81). Neither time nor the specific type of human acclimation we implemented affected cattle temperament, indicating other traits may be more important. Alternatively, different acclimation procedures may be more effective to improve cattle temperament.

51 Effects of acclimation on cattle response to humans while being handled

Abstract The objective of this study was to evaluate the impact of previous human interaction on the behavior of beef cows while they are being handled. To achieve this, 84 F-1 Angus x Brahman cows were randomly assigned to one of two human interaction treatments. The positive human-animal interaction group (P) was subjected to daily contact with a herdsman (on foot) for 15 minutes and was fed supplement by the herdsman. The control group (N) was checked daily and fed from a vehicle, with no direct human interaction. Each acclimation procedure was replicated in 2 pastures/herds (n = 16 to 26 cows in each herd). During routine processing times for these herds (d 0, 256, and 317), herds were gathered from their pastures and temperament was assessed. Chute and alley scores were assigned to individual animals by the same trained observer and ranged from 1 (calm) to 5 (aggressive). Chute exit velocity was also measured. Temperament variables were evaluated with ANOVA as a split plot with acclimation procedure in the whole plots and pasture as the whole-plot experimental unit, and processing time in the split plot. Neither human interaction (P = 0.99) nor time (P = 0.13) affected chute exit velocity. Chute score increased through time (P = 0.01) but was not affected by human interaction (P = 0.70). Alley score was not affected by human interaction (P = 0.32) or time (P = 0.81). Neither time nor the specific type of human acclimation we implemented affected cattle temperament, indicating other traits may be more important. Alternatively, different acclimation procedures may be more effective to improve cattle temperament.

Discrimination of heavy metal acclimated environmental strains by chemometric analysis of FTIR spectra

Heavy metal acclimated bacteria are profoundly the preferred choice for bioremediation studies. Bacteria get acclimated to toxic concentrations of heavy metals by induction of specific enzymes and genetic selection favoring new metabolic abilities leading to activation of one or several of resistance mechanisms creating bacterial populations with differences in resistance profile and/or level. Therefore, to use in bioremediation processes, it is important to discriminate acclimated bacterial populations and choose a more resistant strain. In this study, we discriminated heavy metal acclimated bacteria by using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and multivariate analysis methods namely Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA). Two acclimation methods, acute and gradual, were used which cause differences in molecular changes resulting in bacterial populations with different molecular and resistance profiles. Brevundimonas sp., Gordonia sp., and Microbacterium oxydans were exposed to the toxic concentrations of Cd (30 μg/ml) or Pb (90 μg/ml) by using broth medium as a growth media. Our results revealed that PCA and HCA clearly discriminated the acute-acclimated, gradual-acclimated, and control bacteria from each other in protein, carbohydrate, and whole spectral regions. Furthermore, we classified acclimated (acute and gradual) and control bacteria more accurately by using SIMCA with 99.9% confidence. This study demonstrated that heavy metal acclimated and control group bacteria can be discriminated by using chemometric analysis of FTIR spectra in a powerful, cost-effective, and handy way. In addition to the determination of the most appropriate acclimation procedure, this approach can be used in the detection of the most resistant bacterial strains to be used in bioremediation studies.

Novel imaging technology and procedures for studying brain function in preadolescent awake marmosets

BackgroundNovel imaging technology and procedures were developed to study brain function in preadolescent awake marmosets never exposed to anesthesia. MethodsA radiofrequency transmit and receive, head only volume coil was designed and integrated into a holding system. An acclimation procedure was developed without the use of anesthesia or sedation that allowed for awake imaging. Preadolescent 8-month old male and female marmosets were imaged for resting state BOLD functional connectivity to assess the status of the default mode network. Levels of reactivity during acclimation sessions and behavioral stress following imaging were assessed. ResultsData on functional coupling in the default mode network suggest the organization of connectivity to the prefrontal cortex is not fully developed at 8 months of age. The stress associated with the imaging procedure is comparable to that observed when marmosets are removed from their home cage and temporarily isolated from the family. Comparison to other methodsThe design of the radiofrequency coil provides B1 homogeneity across the entire brain without signal drop off. The unique design of the head cradle obviates the need for any stabilizing surgery, ear bars or bite bar and could be adapted to any size marmoset. The acclimation requires no anesthesia or sedation at any time in the early life of the developing marmoset, a condition that better reflects the human experience. ConclusionA method is provided for imaging functional activity in the brain of fully awake preadolescent marmosets without any history of anesthesia or sedation.

Phenotypic Plasticity Promotes Overwintering Survival in A Globally Invasive Crop Pest, Drosophila suzukii.

Spotted wing drosophila, Drosophila suzukii Matsumura, is a major pest of small fruit worldwide in temperate and subtropical growing regions. In Northern climates, D. suzukii likely overwinters locally under leaf litter and snow pack, but our understanding of the factors affecting thermal susceptibility is limited. While previous investigations of thermal susceptibility in this species have employed conventional static acclimation protocols, we aimed to determine whether gradual cooling, or dynamic acclimation, may extend the limits of known thermal tolerance by more closely approximating naturally occurring shifts in temperature. First, we assessed survival among adult and pupal D. suzukii using static acclimation. Then, we re-assessed survival using a novel dynamic acclimation method. We found that while static acclimation was sufficient to induce cold tolerance, dynamic acclimation significantly improved survival at temperatures as low as −7.5 °C. Following static acclimation, the lower lethal limit of adult D. suzukii was −1.1 °C in winter morphotype (WM) adults compared to 1.7 °C in non-acclimated summer morphotype (SM) adults. Dynamic acclimation reduced the lower limit to −5 °C in SM flies. At the end of our study 50% of WM flies survived 72 h at −7.5 °C. Below 0 °C pupal survival declined significantly regardless of acclimation procedure. However, pupal acclimation improved survival outcomes significantly compared to non-acclimated pupae, suggesting that while juvenile diapause is unlikely, cold hardening likely benefits those flies which may develop into the overwintering WM population. These data suggest that the degree of cold hardening is proportional to the thermal environment, a finding previously unrecognized in this species. Given the economic impact of this pest, these data may have important implications for offseason population monitoring and management. We discuss how phenotypic plasticity may drive geographical range expansion, and the impact of climate change on the spread of this species.

Auditory evoked BOLD responses in awake compared to lightly anaesthetized zebra finches

Functional magnetic resonance imaging (fMRI) is increasingly used in cognitive neuroscience and has become a valuable tool in the study of auditory processing in zebra finches, a well-established model of learned vocal communication. Due to its sensitivity to head motion, most fMRI studies in animals are performed in anaesthetized conditions, which might significantly impact neural activity evoked by stimuli and cognitive tasks. In this study, we (1) demonstrate the feasibility of fMRI in awake zebra finches and (2) explore how light anaesthesia regimes affect auditory-evoked BOLD responses to biologically relevant songs. After an acclimation procedure, we show that fMRI can be successfully performed during wakefulness, enabling the detection of reproducible BOLD responses to sound. Additionally, two light anaesthesia protocols were tested (isoflurane and a combination of medetomidine and isoflurane), of which isoflurane alone appeared to be the most promising given the high success rate, non-invasive induction, and quick recovery. By comparing auditory evoked BOLD responses in awake versus lightly anaesthetized conditions, we observed overall effects of anaesthetics on cerebrovascular reactivity as reflected in the extent of positive and negative BOLD responses. Further, our results indicate that light anaesthesia has limited effects on selective BOLD responses to natural versus synthetic sounds.

Acclimation Strategy Using Complex Volatile Fatty Acid Mixtures Increases the Microbial Fuel Cell (MFC) Potential

AbstractThe start‐up of microbial fuel cells (MFCs) requires biofilm development onto electrodes and acclimation of the microbial community to specific substrates. This process is time‐consuming and shows low effectivity when complex substrates are utilized. The varying proportions and complex mixtures of volatile fatty acids (VFAs) in bioprocess effluents makes it difficult to predict the power output of VFA‐based MFCs when this technology is coupled to a previous bioprocess. In this work, the effect of the degree of reduction of single VFAs on MFC potential was investigated, and a novel acclimation procedure involving the feeding of gradually more complex VFA mixtures is proposed. The power output obtained with butyric acid (6.1 ± 2 mW m−2) was higher than that obtained with propionic acid (5.0 ± 1 mW m−2), as expected based on their degree of reduction. The MFC potential generated by an acetic acid‐fed MFC reached 60 mV, but an acetic‐butyric acid mixture reduced the cell potential by one order of magnitude. The subsequent addition of propionic acid to the acetic‐butyric mixture increased the MFC potential from 1.9 ± 0.1 mV to 35 ± 10 mV in sequential feeding cycles. Consequently, the feeding sequence of acetic, acetic‐butyric, and acetic‐butyric‐propionic acids is proposed as an efficient strategy for the acclimation of MFCs to complex substrates.

A non-invasive restraining system for awake mouse imaging

BackgroundPreclinical neuroimaging allows for the assessment of brain anatomy, connectivity and function in laboratory animals, such as mice and rats. Most of these studies are performed under anesthesia to avoid movement during the scanning sessions. MethodDue to the limitations associated with anesthetized imaging, recent efforts have been made to conduct rodent imaging studies in awake animals, habituated to the restraint systems used in these instances. As of now, only one such system is commercially available for mouse scanning (Animal Imaging Research, Boston, MA, USA) integrating the radiofrequency coil electronics with the restraining element, an approach which, although effective in reducing head motion during awake imaging, has some limitations. In the current report, we present a novel mouse restraining system that addresses some of these limitations. Results/Comparison to other methodsThe effectiveness of the restraining system was evaluated in terms of three-dimensional linear head movement across two consecutive functional MRI scans (total 20min) in 33 awake mice. Head movement was minimal, recorded in roughly 12% of the time-series. Respiration rate during the acclimation procedure dropped while the bolus count remained unchanged. Body movement during functional acquisitions did not have a significant effect on magnetic field (B0) homogeneity. Conclusion/noveltyCompared to the commercially available system, the benefit of the current design is two-fold: 1) it is compatible with a range of commercially-available coils, and 2) it allows for the pairing of neuroimaging with other established techniques involving intracranial cannulation (i.e. microinfusion and optogenetics).

Anode acclimation methods and their impact on microbial electrolysis cells treating fermentation effluent

There is a lack of standardized acclimation procedures for evaluating treatability of different wastewaters, and such tests are often conducted using different types of microbial electrolysis cells (MECs). Two different types of MECs (mini or cube) were therefore acclimated using two different substrates (acetate or domestic wastewater) to see the impact of these procedures on the resulting treatment efficiency using the same cellulose fermentation effluent. COD removal was slightly larger using mini MECs (81–86%) than cube MECs (79–82%). Pre-acclimation of mini MECs to domestic wastewater increased COD removal slightly compared to non-acclimated tests with fermentation effluent, but acclimation differences for the cube MECs were not statistically significant. Gas production was not significantly different for cube pre-acclimated MECs compared to those acclimated only to the fermentation effluent. Current densities were higher for the cube reactors than the mini MECs, but they were unaffected by acclimation procedure (pre-acclimation or direct use of fermentation effluent). These results show that mini MECs acclimated to a readily available complex source of organic matter (domestic wastewater) can produce equivalent or slightly superior results for tests with a different complex wastewater (fermentation effluent), and that mini MEC performance is comparable to that of cube MECs. The similarity of reactor performance allows the use of simple and inexpensive mini MECs that can be acclimated to domestic wastewater and subsequently used to test different types of industrial effluents.

Biodegradation of olive mill wastewater in a membrane bioreactor: acclimation of the biomass and constraints

In order to overcome the toxic effect of olive mill wastewater (OMWW) on biomass during biological treatment, this work will test OMWW biodegradation in a membrane bioreactor (MBR) using an acclimation procedure and will study its constraints. Special focus will be put on soluble microbial products (SMP) analysis in MBR and their impact on membrane fouling. The study was realized in an external ceramic ultrafiltration MBR which offers more flexibility than the other biological treatments (i.e. independence between both hydraulic and sludge retention time) and a smaller footprint. Fed with a mass ratio of 40% OMWW/60% glucose, MBR biomass showed efficient chemical oxygen demand and polyphenols removal rates of, respectively, 90 and 65% despite a low activity of 3.2 mgO2 gMLVSS−1 h−1 due to the harsh and toxic environment. Moreover, HPLC analysis has showed a removal from the permeate of the major phenolic compounds including hydroxytyrosol, tyrosol, and caffeic acid. The monitoring of SMP concentrations has contributed to identify the presence of an environmental stress during OMWW input. Polysaccharide and protein are the main SMP fractions released with, respectively, 10 ± 0.1–20 ± 0.5 mg gMLVSS−1 and 4 ± 0.01–8 ± 0.01 mg gMLVSS−1. These SMP and higher molecular weight compounds brought by OMWW were found to be partially responsible for the intensive membrane fouling obtained. The feasibility of biomass acclimation directly to OMWW composed of multi-phenolic compounds was proved in MBR and its constraints were discussed. Microfiltration membrane would be suggested to overcome the constraints observed when ultrafiltration membrane was used (150 kDa).

Housing Conditions Differentially Affect Physiological and Behavioural Stress Responses of Zebrafish, as well as the Response to Anxiolytics

Zebrafish are a widely utilised animal model in developmental genetics, and owing to recent advances in our understanding of zebrafish behaviour, their utility as a comparative model in behavioural neuroscience is beginning to be realised. One widely reported behavioural measure is the novel tank-diving assay, which has been often cited as a test of anxiety and stress reactivity. Despite its wide utilisation, and various validations against anxiolytic drugs, reporting of pre-test housing has been sparse in the literature. As zebrafish are a shoaling species, we predicted that housing environment would affect their stress reactivity and, as such, their response in the tank-diving procedure. In our first experiment, we tested various aspects of housing (large groups, large groups with no contact, paired, visual contact only, olfactory contact only) and found that the tank diving response was mediated by visual contact with conspecifics. We also tested the basal cortisol levels of group and individually housed fish, and found that individually housed individuals have lower basal cortisol levels. In our second experiment we found ethanol appeared to have an anxiolytic effect with individually housed fish but not those that were group housed. In our final experiment, we examined the effects of changing the fishes' water prior to tank diving as an additional acclimation procedure. We found that this had no effect on individually housed fish, but appeared to affect the typical tank diving responses of the group housed individuals. In conclusion, we demonstrate that housing represents an important factor in obtaining reliable data from this methodology, and should be considered by researchers interested in comparative models of anxiety in zebrafish in order to refine their approach and to increase the power in their experiments.

Development and Validation of a Behavioral Acclimation Protocol for Cats to Respiration Chambers Used for Indirect Calorimetry Studies

Cats exposed to novel environments initiate stress responses by behavioral and physiological changes that modify metabolism and lead to the collection of unreliable data. Fourteen cats (10 ± 2 months) were subjected to an 11-week acclimation procedure to adapt to restriction within chambers used for indirect calorimetry studies. Cats were acclimated to chambers in their home environments, to chambers in the study room, and to increasing periods of restriction within chambers. Ten additional cats (11 ± 1 month), used as controls, were subjected to a single 5-hr restriction without any prior exposure. Stress level, feed intake, fearfulness, and eliminations were recorded. Latencies to approach a novel object peaked on Weeks 4 and 8 (p < .05). Cat-Stress-Scores (CSS) declined with exposure and on Week 11, stress levels were low and consistent (p < .05). CSS was greater in unacclimated versus acclimated cats (p < .05). In conclusion, acclimation protocols prepare cats for repeated, temporary restriction within chambers, whereas short acclimations do not. A step-up acclimation procedure with behavioral indices of stress should be utilized to prepare cats for research that necessitates restriction.

Development and validation of a behavioral acclimation protocol for cats to respiration chambers used for indirect calorimetry studies

Cats exposed to stressful and novel environments initiate stress responses as evidenced by behavioural and physiological changes which, in turn, modify energy requirement and metabolism leading to the collection of unreliable results from nutritional trials conducted on stressed cats. 14 cats (10 ± 2 months) were subjected to an 11 week acclimation procedure to adapt cats to restriction within a chamber used for calorimetry studies. Cats were acclimated to the chambers on weeks 1–3, the study room on weeks 4–6 and increasing restriction periods of 1 to 20 hrs within the chamber on weeks 7–11. Ten additional cats (11 ± 1 month), used as controls, were subjected to 5 hrs of restriction without prior chamber or study room exposure to compare responses. Stress level, feed intake, fearfulness and eliminations were recorded. Cat‐Stress‐Scores (CSS) and latencies to approach a novel object peaked on weeks 4 and 7 (P&lt;0.05). CSS declined with exposure to a novel experience and on week 11, stress levels were low and consistent (P&lt;0.05). CSS was greater in un‐acclimated as compared to acclimated cats (P&lt;0.05). In conclusion, acclimation protocols prepare cats for repeated, temporary restriction, whereas short acclimations do not. A step up acclimation procedure with behavioral indices of stress should be utilized to prepare cats for research that necessitates restriction. Supported by: The Procter and Gamble Co., Pet Care, Ohio, USA.

Salinity tolerance of laboratory reared juveniles of the fat snook centropomus parallelus

The knowledge of salinity tolerance is essential for aquaculture production in different water sources, as well as for stocking enhancement programs. In the present experiment, salinity tolerance was investigated in laboratory reared juveniles of the fat snook Centropomus parallelus. Fish of 52 days (22.0 mm ± 0.4: mean total length ± SEM), 59 days (22.6 mm ± 0.5) and 73 days (25.8 mm ± 0.5) after hatching (DAH) were directly transferred from 35 to 0, 5, 15 and 35 ppt. Survival was checked every 24 h during a 96-h period. The experiment was carried out with fed (for all salinities) and unfed individuals (except for 5 ppt). Direct transfer resulted in less than 40% mortality in all treatments and ages tested. At the same salinity level, no difference in survival rates was found between fed and unfed juveniles, at the different ages and exposure time tested. Juveniles of 52 DAH presented lower tolerance to 0 ppt compared to other salinities. In older juveniles (59 and 73 DAH), mortality after 96 h was very low ( &gt; 95% survival), regardless the salinity treatment or feeding condition. Therefore, the present study showed that juveniles of 52 DAH are less tolerant to abrupt transfer to freshwater, indicating that a salinity acclimation procedure prior to release in freshwater areas would be necessary, and that tolerance increased with increasing age.

Functional Magnetic Resonance Imaging in Conscious Animals: A New Tool in Behavioural Neuroscience Research

Functional magnetic resonance imaging (fMRI) is a unique window to the brain, enabling scientists to follow changes in brain activity in response to hormones, ageing, environment, drugs of abuse and other stimuli. There are two features that make fMRI unique when compared with other imaging modalities used in behavioural neuroscience. First, it can be entirely noninvasive: each animal can serve as its own control over the natural course of its life, vital for following neuroadaptation and other developmental processes critical to understanding behaviour. Second, fMRI has the spatial and temporal resolution to observe patterns of neuronal activity across the entire brain in less than a minute. Although fMRI does not have the cellular spatial resolution of immunostaining, nor the millisecond temporal resolution of electrophysiology, synchronised changes in neuronal activity across multiple brain areas seen with functional MRI can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviours. Thus, fMRI affords a systems approach to the study of the brain, complementing and building from other neurobiological techniques to understand how behaviour is organised across multiple brain regions. In this review, we present a general background to fMRI and the different imaging modalities that can be used in fMRI studies. Included are examples of the application of fMRI in behavioural neuroscience research, along with discussion of the advantages and disadvantages of this technology.

Procedure for minimizing stress for fMRI studies in conscious rats

Functional magnetic resonance imaging (fMRI) in conscious animals is evolving as a critical tool for neuroscientists. The present study explored the effectiveness of an acclimation procedure in minimizing the stress experienced by the animal as assessed by alterations in physiological parameters including heart rate, respiratory rate, and serum corticosterone levels. Results confirm that as the stress of the protocol is minimized, there is a significant decrease in head movements and enhancement in data quality. The feasibility of improving the quality of fMRI data acquired in alert rats by utilizing a relatively simple technique is presented.

Recent developments and improvements in ornamental fish packaging systems for air transport

Current ornamental ¢sh packaging systems are characterized by very high ¢sh loading densities and high metabolic wastes in the transport water after shipment. They focus mainly on management of the quality of transport water. Recent studies using the guppy as a model ¢sh showed that post-shipment mortality could be reduced through enhancement of the stress resistance of the ¢sh, and hence emphases should also be placed on the preparation of the ¢sh for transport and recovery of the ¢sh after shipment. Farmers can contribute signi¢cantly by applying nutritional prophylaxis before harvesting. Exporters may use the salinity stress test to identify ¢sh lots of good quality for transport, apply health prophylaxis to eradicate parasites and optimize other techniques such as starvation of the ¢sh or addition of salt to the transport water to enhance the stress resistance of the ¢sh. Importers may adopt proper acclimation procedure and allow ¢sh to recover in low salinity water to reduce post-shipment mortality. As the main bulk of post-shipment mortality is stressmediated and occurs during the 1-week recovery period, the industry should consider revising the basis of the current warranty system for their customers, from death on arrival to cumulative mortality at 7 days post shipment (or death after 7 days, DA7), in order to cut down ¢sh losses after shipment.