The effect of salty diets and gradual transfer to sea water on osmotic adaptation, gill Na+, K+-ATPase activation, and survival of brook charr, Salvelinus fontinalis, Mitchill

The intensity and duration of the period of osmotic disturbance during introduction of brook charr into sea water were decreased by introducing the fish according to a gradient of salinity over a period of 6 days. Survival in summer increased from 25 to 90% with the use of a salinity gradient. However, kinetics and levels of activation of the gill Na⁺, K⁺-ATPase were not affected by the mode used for introducing brook charr into sea water. Neither was its level of activity modified by the use of a salted diet when the fish were in fresh water. The addition of 8 and 12% of salt to the diet prevented the plasma electrolyte surge of concentrations during the first days in sea water. In very cold water, survival rate was also drastically improved by giving an 8% salted diet during the 6 weeks preceding the introduction into sea water. These results show that both salty diets and exposure to brackish water during 6 days help brook charr face osmotic stress and improve their survival rate when introduced into full-strength sea water. The combined use of these preconditioning strategies might facilitate rearing this species in sea cages or silos.     

Mortality of Baltic sea trout (Salmo trutta) after release from gillnets

We explore the mortality rate of disentangled sea trout in whitefish fishery using gillnets with a 35–43 mm bar length. The study was conducted during the main fishing seasons in the Gulf of Bothnia in the northern Baltic Sea. Overall 59.5% of the sea trout were alive at the end of a 2–7 day observation period following release from the gillnets. Altogether, 12.1% of the captured fish were found dead in gillnets and 28.4% died due to injuries during an extended observation period. The average length of the captured sea trout was 435 mm, indicating that the majority were spending their first or second year at sea. The proportion of the survived and not injured (no observed damage) fish was highest in larger fish, >450 mm. The injured and not injured fish died equally frequently. Post capture survival was not connected to the removal time from gillnets or type of observed injuries but to the type of entanglement. Most of the fish were entangled by a mesh around the body, which caused extensive scale loss and open sores on the skin. The smallest fish may have had internal wounds that were not registered in this study. These results can be used in fisheries management to estimate the mortality of multi‐species gillnet fishing to sea trout populations in relation to management actions.     

The rate of predation by fishes on hatchlings of the green turtle (Chelonia mydas)

This study addresses the need for empirical data on the survival of sea turtle hatchlings after entry into the sea by (1) developing a method for measuring marine predation; (2) estimating predation rates while crossing the reef; and (3) investigating the effect of environmental variables on predation rates. Predation rates were quantified by following individual hatchlings, tethered by a 10m monofilament nylon line, as they swam from the water's edge towards the reef crest. Predation rates under particular combinations of environmental variables (tide, time of day, and moon phase) were measured in separate trials. Predation rates varied among trials from 0 to 85% with a mean of 31% (SE=2.5%). The simplest logistic regression model that explained variation in predation contained tide and moon phase as predictor variables. The results suggest that noctural emergence from the nest is a behavioral adaptation to minimize exposure to the heat of the day rather than a predator-escape mechanism. For the green turtle populations breeding in eastern Australia, most first year mortality is caused by predation while crossing the reef within the first hour of entering the sea.     

The Effect of Novel Research Activities on Long-term Survival of Temporarily Captive Steller Sea Lions (Eumetopias jubatus)

Two novel research approaches were developed to facilitate controlled access to, and long-term monitoring of, juvenile Steller sea lions for periods longer than typically afforded by traditional fieldwork. The Transient Juvenile Steller sea lion Project at the Alaska SeaLife Center facilitated nutritional, physiological, and behavioral studies on the platform of temporary captivity. Temporarily captive sea lions (TJs, n = 35) were studied, and were intraperitoneally implanted with Life History Transmitters (LHX tags) to determine causes of mortality post-release. Our goal was to evaluate the potential for long-term impacts of temporary captivity and telemetry implants on the survival of study individuals. A simple open-population Cormack-Jolly-Seber mark-recapture model was built in program MARK, incorporating resightings of uniquely branded study individuals gathered by several contributing institutions. A priori models were developed to weigh the evidence of effects of experimental treatment on survival with covariates of sex, age, capture age, cohort, and age class. We compared survival of experimental treatment to a control group of n = 27 free-ranging animals (FRs) that were sampled during capture events and immediately released. Sex has previously been show to differentially affect juvenile survival in Steller sea lions. Therefore, sex was included in all models to account for unbalanced sex ratios within the experimental group. Considerable support was identified for the effects of sex, accounting for over 71% of total weight for all a priori models with delta AICc <5, and over 91% of model weight after removal of pretending variables. Overall, most support was found for the most parsimonious model based on sex and excluding experimental treatment. Models including experimental treatment were not supported after post-hoc considerations of model selection criteria. However, given the limited sample size, alternate models including effects of experimental treatments remain possible and effects may yet become apparent in larger sample sizes.     

ACCLIMATION TO CAPTIVITY: A QUANTITATIVE ESTIMATE BASED ON SURVIVAL OF BOTTLENOSE DOLPHINS AND CALIFORNIA SEA LIONS

An estimate of how long marine mammals need to acclimate to captivity would permit more precise comparisons of husbandry practices, yet no quantitative analysis of acclimation has been performed. Therefore, we estimated the duration of acclimation to captivity for bottlenose dolphins (BD) and California sea lions (CSL) by comparing 5-d survival rates during the first 90 d of captivity with a survival rate based on days 91-365 in captivity. Wild-born BD (n = 1,270) and CSL (n = 1,650) acclimate to captivity in approximately 35 and 40 d, respectively, whereas captive born BD (n = 332) and CSL (n = 992) acclimate in approximately 50 and 40 d, respectively. When transferred between two institutions, BD (n = 911) acclimated in the same amount of time (45 d) as when first transferred from the wild, whereas transferred CSL (n = 336) acclimated more rapidly (15 VJ. 40 d) than when first transferred from the wild. Based on results from these two species, a 60-d acclimation period is recognized as a distinct interval of relatively high mortality that should be treated separately from long-term survival estimates when evaluating husbandry practices of ocean-aria and zoos.     

Mechanical disturbance affects haemocyte functionality in the Venus clam Chamelea gallina

The clam Chamelea gallina is fairly common along the western coastline of the Adriatic Sea, where it is subjected to intense fishing. To evaluate possible causes of stress in clam populations, the effects of acute mechanical disturbance on haemocyte functionality were analysed in both laboratory and field experiments. Among the various sources of stress that clams undergo during commercial fishing by hydraulic dredges, water pressure and mechanical sorting were considered, and three increasing levels of stress were applied. A reduction in immunosurveillance was highlighted, concentrations of circulating haemocytes, phagocytic and acid phosphatase activity indices decreased with increasing mechanical stress. The opposite trend shown by the beta-glucuronidase activity index is discussed. The response of clam haemocytes, detected on seasonal bases in two sites, often exhibited peculiar patterns, mostly depending on the reproductive cycle, and were probably influenced by different features of the sea bottom. Although recovery after stress was observed in laboratory experiments, some considerations are made on detrimental effects experienced in the field by under-sized clams, which are first fished and then thrown back into the sea.     

Stress responses of the sea cucumber Holothuria forskali during aquaculture handling and transportation

Animal welfare during handling and transportation to aquaculture facilities or public aquaria is commonly estimated by addressing injury and mortality levels. Although these procedures have been optimized for different species, data on individual species’ cellular capabilities to tolerate stress are still scarce. In the present study, several biomarkers related with oxidative stress and energy metabolism were assessed in Holothuria forskali during animal acclimation, pre-transport, transport and quarantine. Combined analyses confirmed that sea cucumbers experienced high oxidative stress during transport, but had the capability to deal with it using a complex of cellular defence mechanisms, which enabled recovery from oxidative stress without permanent damage. Through a better understanding of individual species and the development of optimal parameters, this approach has the potential to improve animal wellbeing during and after acclimation, transportation and recovery processes.     

Juvenile production of the red sea urchin Strongylocentrotus franciscanus (Echinodermata: Echinoidea) in Baja California, Mexico

The red sea urchin Strongylocentrotusfranciscanus (Agassiz 1863) is harvested commercially in Baja California, Mexico, since 1970; however, in the last ten years the capture per unit effort (CPUE) has decreased from 310 kg/fishing unit/day to 120 kg/fishing unit/day. For this reason, actions were taken to develop a culture technology allowing massive production of juveniles for re-stocking natural populations or for growing them commercially. We summarize some of the basic studies and main achievements in this effort. In Baja California, considerably faster larval development (approximately 21 days) has been attained than in the US northwest coast (62 days). Spawning of red sea urchins was routinely induced with KCI while egg fertilization was performed using a 100,000-sperm/ml solution. Six microalgae species were tested and Rhodomonas sp. produced the best larval development. The mean survival rate at the end of the larval period was 25%, but results varied widely with bactch. From the feed ratios tested, best results were obtained using 7000 cel/ml during the first week of larval development, followed by 10,000 cel/ml during the second and 15,000 cel/ml during the third week. KCl proved the most consistent metamorphic inducer, regularly yielding metamorphosis percentages higher than 90%. Metamorphosis was considered complete when the functional jaw that juveniles use for first benthic feeding appeared (as soon as 20 days after induction). With this method several thousands of red sea urchin juveniles were produced. They reached up to 1.5 mm in size during the first 50 days of culture after metamorphosis, showing the great potential for mass production of this species in the laboratory.     

Stress,Behaviour and Immunity in Wild‐Caught Wintering Great Tits (Parus major)

The associations between behaviour, stress and immune responses are most likely a result of common integration through the neuroendocrine system. Here, we describe associations between behaviour and immunity in great tits, Parus major. Wild‐caught birds were brought into captivity, and their immune function was assessed on the basis of antibody production to a novel Brucella abortus antigen and of heterophil/lymphocyte (H/L) ratio, which is also a haematological marker of stress. Two behavioural traits were evaluated: tolerance to captive conditions on the basis of damage inflicted to tail feathers and propensity to produce alarm calls at release. The birds that had highest H/L ratios at capture inflicted the maximum extent of tail damage during the week spent in captivity and produced lowest antibody titres against a novel antigen, which indicates a strong covariation between the tolerance of captivity, perceived stress and immune responsiveness. Propensity to produce alarm calls was lower in birds who tolerated captivity better. Structural equation modelling proposed the existence of an underlying latent variable affecting all the measured traits and causing the correlations between traits. Our study indicates that connections between behaviour and immunity can be easily detected in wild animals.     

Behavioral and hormonal consequences of transporting giant pandas from China to the United States

Zoological institutions strive to ensure the welfare of nonhuman animals in captivity. Part of this effort involves reducing the level of distress experienced by an animal to the greatest extent possible. However, some necessary zoo management practices such as transportation induce stress responses. An extensive literature exists concerning the animal welfare implications of road transportation for farm and laboratory animals. There has, however, been little focus on the effects of air transportation on wild animals in captivity. Because many endangered species are transported by air for breeding purposes, it is especially important to study the effects of stress on these species. This study investigated the behavioral and hormonal consequences of transporting 4 giant pandas (2 male-female pairs) by air from China to the United States. An autoregressive test revealed that urinary cortisol measures were highest for 2 subjects, Lun Lun and Tian Tian, during the flight than during the remainder of the 30-day period posttransport (p < .01). No long-term behavioral changes or problems emerged as a result of the transport. The study found that more research is needed to develop a complete understanding of transportation stress and welfare in captive wildlife.     

Physiological changes in the brushtail possum (Trichosurus vulpecula) following relocation from Armidale to Brisbane, Australia.

To determine the effect of relocation on the health of possums the body weights and hormone and immune responses of six male and nine female brushtail possums were monitored for 20 weeks following transfer from the environs of Armidale into enclosures in Brisbane. Over the first 6 weeks of captivity, male possums lost 11.0% of their original body weight and females lost 16.8%. The mean concentrations of plasma cortisol in the male and female possums were 14.5 and 29.4 ng/mL, respectively, and did not change over the 20-week period. Male and female possums displayed a similar pattern of thyroxine secretion over the 20 weeks, with low concentrations up to week seven (2.1 and 2.7 ng/mL, respectively) increasing to 6.9 and 5.8 ng/mL in weeks 7-12 (P < 0.005). This increase in the concentration of thyroxine corresponded with the increase in body weight. The number of white blood cells (WBCs) and the percentage of neutrophils increased from the capture to week 6-10. However, during the last 10 weeks of captivity the number of WBCs and the percentage of neutrophils decreased, indicating recovery of the immune system. This was in accord with the proliferative response of lymphocytes to the T cell mitogen PHA that increased from weeks 11-15 to weeks 16-20 in both male and female possums. The results above suggest that the Armidale possums, like the Brisbane possums, were stressed following their relocation; however, their immune systems were able to gradually recover as they adjusted to their new environment in Brisbane. The death rate of pouch young and of adult female possums after relocation was considerably higher in the Armidale possums compared to Brisbane possums. The mortality rate of Brisbane possums over the first 20 weeks of captivity was 8.3% and 19.6% for male and female possums, respectively, and for Armidale possums 16.6% and 47.1%, respectively. The possums transferred from the environs of Armidale into captivity in Brisbane were under greater stress than possums captured in Brisbane and placed in captivity in Brisbane.     

Assessing release protocols for Canada lynx reintroduction in colorado

Reintroductions are a common strategy to restore ecosystem integrity, especially when top predators are involved. Reintroductions are often time consuming, expensive, and controversial, and thus understanding what aspects are important for a successful program is needed. Focusing on the example of the reintroduction of Canada lynx (Lynx canadensis) to Colorado, we investigated how different release protocols (RP) affected mortality within the first year post-release. We found that average monthly mortality in the study area during the first year decreased with time in captivity from 0.205 (95% CI = 0.069, 0.475) for lynx having spent up to 7 days in captivity to 0.028 (95% CI = 0.012, 0.064) for lynx spending >45 days in captivity before release. Our results also suggest that keeping lynx in captivity beyond 5–6 weeks accrued little benefit in terms of monthly survival. We found that, on a monthly average basis, lynx were as likely to move out (P = 0.196, SE = 0.032) as well as back onto (P = 0.143, SE = 0.034) the reintroduction area during the first year after release. Mortality was 1.6 times greater outside of the study area, suggesting that permanent emigration and differential mortality rates on and off reintroduction areas should be factored into sample size calculations for an effective reintroduction effort. A post-release monitoring plan is critical to providing information to assess aspects of RP and to improve survival of individuals. Future lynx and other carnivore reintroductions may use our results to help design reintroduction programs including both the release and post-release monitoring protocols. © 2011 The Wildlife Society.     

Haptoglobin concentrations in free-range and temporarily captive juvenile steller sea lions

Haptoglobin (Hp) is an acute-phase protein synthesized in the liver that circulates at elevated concentrations in response to tissue damage caused by inflammation, infection, and trauma. As part of a larger study, sera Hp concentrations were measured in temporarily captive (n = 21) and free-range (n = 38) western stock juvenile Steller sea lions (Eumetopias jubatus) sampled from 2003 to 2006. Baseline Hp concentration at time of capture was 133.3 +/- 17.4 mg/dl. Temporarily captive animals exhibited a 3.2-fold increase in Hp concentrations during the first 4 wk of captivity, followed by a return to entry levels by week 5. Haptoglobin levels were not influenced by age, season, or parasite load. There was a significant positive correlation between Hp concentrations and white blood cell count (P < 0.001) and globulin levels (P < 0.001) and a negative correlation to red blood cell count and hematocrit (P < 0.001 for both). There was no correlation between Hp levels and platelet count (P = 0.095) or hemoglobin (P = 0.457). Routine blubber biopsies collected under gas anesthesia did not produce a measurable Hp response. One animal with a large abscess had an Hp spike of 1,006.0 mg/dl that returned to entry levels after treatment. In conclusion, serum Hp levels correlate to the stable clinical health status observed during captivity, with moderate Hp response during capture and initial acclimation to captivity and acute response to inflammation and infection.     

Fin damage in captured and reared squids

Fin damage was a major factor in the mortality of wild-caught squids kept in the laboratory. Infection of abraded fins by opportunistic bacterial pathogens impaired swimming and led to death. Serious skin abrasions were especially common in trawl-caught squids. Dipnets and jigs inflicted minimal trauma and were preferred for squid capture. Fin damage also occurred during transportation and during maintenance of squids in onshore tanks. A successful aquarium system with recycled sea water was used for squid maintenance. Hatchling, juvenile and adult loliginid squids remained healthy in closed-system aquaria for periods ranging from 1 to 16 weeks.     

Physiological changes in the Norway lobster Nephrops norvegicus (L.) escaping and discarded from commercial trawls on the West Coast of Scotland: 1. Body fluid volumes and haemolymph composition after capture and during recovery

The Norway Lobster Nephrops norvegicus (L.) was captured by trawling at depths of 120 to 150 m off the West Coast of Scotland using commercial fishing gears. Discarded animals (normally <25–35 mm carapace length) were sampled immediately after capture, and following emersion (exposure to air) on deck for 1 or 2 h. Their recovery from, and survival of, the stresses of being fished were examined in separate groups of animals transferred by SCUBA divers to underwater (u/w) cages on the seabed at a mean depth of 24 m. “Escaped” N. norvegicus were collected in a small-meshed (40 mm) “cover” around the cod-end and sampled without emersion. It was assumed that the physiological state of these animals would be similar to those passing through the cod-end meshes directly back into the surrounding sea during normal fishing operations. Groups of escaped animals were also transferred to u/w cages for recovery and survival studies. Control animals (creel-caught from the same fishing grounds) were sampled after recovery in u/w cages. Total body water content, haemolymph (blood) volume and composition were examined at various stages after capture and during recovery of control, discarded and escaped animals. Discarded animals showed significant reductions in total body water content compared to controls but recovered after 24 h. Controls that had been artificially damaged by puncturing also showed a reduction in water content. Escaped animals showed significantly higher mean water content compared to discards. Haemolymph volumes were also reduced in discarded animals suggesting that significant blood loss occurs during capture. There was also evidence of a shift of fluid from haemolymph to tissues in discarded animals. Pericardial (haemolymph) pressures were much reduced in discards compared to undisturbed control animals but showed significant recovery in surviving animals. Pressure reduction was less in escapes but was seen in control animals that had been exercised to exhaustion. Haemolymph osmotic concentrations, [Na⁺] and [K⁺] showed increases after discarding, notably after emersion, but haemocyanin [Hcy] and total haemolymph protein concentrations were less affected. The effect of these changes on longer term survival and recovery from the stress of capture are discussed.     

Captive Housing during Water Vole (Arvicola terrestris) Reintroduction: Does Short-Term Social Stress Impact on Animal Welfare?

Background

Animals captive bred for reintroduction are often housed under conditions which are not representative of their preferred social structure for at least part of the reintroduction process. Specifically, this is most likely to occur during the final stages of the release programme, whilst being housed during transportation to the release site. The degree of social stress experienced by individuals during this time may negatively impact upon their immunocompetence.

Methodology/Principal Findings

We examined two measure of stress - body weight and Leukocyte Coping Capacity (LCC) - to investigate the effects of group size upon captive-bred water voles destined for release within a reintroduction program. Water voles were housed in laboratory cages containing between one and eight individuals. LCC scores were negatively correlated with group size, suggesting that individuals in larger groups experienced a larger degree of immuno-suppression than did individuals housed in smaller groups or individually. During the course of the study mean body weights increased, in contrast to expectations from a previous study. This was attributed to the individuals sampled being sub-adults and thus growing in length and weight during the course of the investigation.

Conclusions/Significance

The reintroduction process will inevitably cause some stress to the release cohort. However, for water voles we conclude that the stress experienced may be reduced by decreasing group size within captive colony and/or transportation housing practises. These findings are of significance to other species'' reintroductions, in highlighting the need to consider life-history strategies when choosing housing systems for animals being maintained in captivity prior to release to the wild. A reduction in stress experienced at the pre-release stage may improve immunocompetence and thus animal welfare and initial survival post-release.     

Physiological response to capture stress in endemic Southern African catsharks (family Scyliorhinidae)

Fishing is the major threat to marine fish populations, particularly to higher trophic-level predators such as sharks. Many sharks, and other fish, are caught as commercial by-catch or for recreational purposes and then released; therefore, it is important to understand the effects of capture stress on their physiology and subsequent survival. Nonetheless, although important data have been collected for some sharks, there can be substantial interspecific differences, and the consequences of capture stress are still poorly understood for most species. In this study, the authors quantified the physiological effect of capture on four catshark species endemic to Southern Africa, which are regularly discarded as by-catch and targeted by recreational fisheries. Fifteen pyjama sharks, nine leopard sharks and nine shysharks were captured, and a blood sample was collected to measure their physiological response to capture stress. Stressed blood biochemistry was compared to samples obtained after the sharks recovered for 24 h in an underwater pen. Levels of pH and K⁺ were significantly lower, and lactate levels were significantly higher, in sharks immediately after capture stress compared to after the 24 h recovery period. Although the species showed a similar response to capture stress, they differed significantly in pH, K⁺ and lactate levels, and there was some evidence of size affecting the strength of the response to capture stress. The substantial physiological response elicited by even the relatively quick capture event in this study suggests that common fishing practices will have a stronger impact on catshark homeostasis because of longer hooking times and more disruptive fishing gear. Although the relationship between survival and physiological changes elicited by capture needs further investigation, the results provide further evidence that minimizing stress would be beneficial to maximize the survival of sharks and other fish following capture-and-release fishing practices.     

基于广义可加模型的时空和环境因子对东南太平洋智利竹筴鱼渔场的影响

根据2001-2007年我国渔船在东南太平洋海域的智利竹筴鱼生产统计数据、时空因子以及海表温度、叶绿素浓度、海表温度梯度等环境数据,利用广义可加模型（GAM）分析了智利竹筴鱼资源变动情况及其与时空和环境因子的关系.结果表明：GAM模型对单位捕捞努力量渔获量(catch per unit effort,CPUE)总偏差解释率为31.47%;竹筴鱼生产具有明显的季节变化,主要集中在第17～41周,其中第25～31周的CPUE较高;东南太平洋智利竹筴鱼作业渔场集中在78°-98° W,30°-435° S之间,适宜海表温度为12 ℃～18 ℃,14 ℃～16 ℃最适宜,适宜叶绿素浓度在0.09～0.18 mg·m^-3,海表温度梯度在0.3 ℃～1.9 ℃.逐步建模法结果表明,影响竹筴鱼资源丰度的因子按重要性从大到小依次为周次、年份、海表温度、经度、纬度、叶绿素浓度和海表温度梯度.     

Developmental cell death in the liver and newborn lethality of Ku86 deficient mice suppressed by antioxidant N-acetyl-cysteine

Repair of DNA double-strand breaks (DSBs) is essential for genome integrity and cell survival. Ku86 is involved in the repair of DNA DSBs by non-homologous end joining (NHEJ). Mice deficient in Ku86 show growth retardation, dwarfism, premature aging, and immunodeficiency. In this study, we observed severely compromised survival of Ku86(-/-) mice, such that most Ku86(-/-) mice died within the first postnatal weeks and only 1.5% of the expected 25% from heterozygous crosses survived for 1 month. Since post-mortem analysis was not possible due to parental cannibalism, histopathological examination was performed on Ku86(-/-) fetuses to assess possible causes of newborn death. Eighty percent and 75% of Ku86(-/-) fetuses exhibited apoptosis and necrosis in the liver, while only 20% and 10% of Ku86(+/+) littermates had apoptosis and necrosis, respectively. In addition, the severity of liver damage was significantly higher in Ku86(-/-) fetuses. Developmental liver damage may have led to postnatal lethality because the fetal liver with pre-existing injury may not be able to undergo transformation from a lymphohematopoietic to an indispensable metabolic organ. Free radicals can cause chromosomal breaks and lead to cell death. We postulated that endogenous oxidative stress might be involved in the resulting liver damage and animal lethality in Ku86(-/-) mice deficient in DNA DSB repair. This hypothesis was tested by treating Ku86(-/-) mice with the well known free radical scavenger, thiol antioxidant N-acetyl-cysteine (NAC), during embryonic development. We found that a significantly higher percentage, 7.7% of NAC treated Ku86(-/-) offspring versus 1.5% untreated Ku86(-/-) mice were alive at 1 month of age. In addition, the incidence of liver necrosis decreased by 21% and the severity of necrosis significantly reduced. Thus, Ku86 deficiency results in severe developmental liver damage and newborn lethality associated with oxidative stress.