Changes in haematological parameters associated with capture and captivity of the marine teleost, Pleuronectes platessa L

After capture by trawling, the blood parameters of plaice (Pleuronectes platessa L.) are perturbed for up to 5 days post-capture. Whole blood values recovered from an initial stress-induced haemoconcentration within 12 hr. There is a marked hyperglycaemia following capture: blood glucose concentration increased four-fold to 87.92 +/- 10.41 mg/100 ml (N = 6) after 12 hr and remained elevated for 3-4 days before returning to normal values. Monovalent blood electrolytes (Na+, K+, Cl-) significantly increased during the initial stages post-capture (4-10 hr) but then recovered. The divalent cations (Ca2+, Mg2+) similarly increased but for a longer period (24-72 hr). Liver and muscle glycogen concentrations were very variable during the recovery period. All blood parameters achieved stable values within 5 days of capture. This study provides comprehensive haematological data on post-trawl recovery and tank-acclimation in plaice, for up to 28 days following capture.     

Effectiveness of Partial Sedation to Reduce Stress in Captured Mule Deer

Information garnered from the capture and handling of free-ranging animals helps advance understanding of wildlife ecology and can aid in decisions on wildlife management. Unfortunately, animals may experience increased levels of stress, injuries, and death resulting from captures (e.g., exertional myopathy, trauma). Partial sedation is a technique proposed to alleviate stress in animals during capture, yet efficacy of partial sedation for reducing stress and promoting survival post-capture remains unclear. We evaluated the effects of partial sedation on physiological, biochemical, and behavioral indicators of acute stress and probability of survival post-capture for mule deer (Odocoileus hemionus) that were captured via helicopter net-gunning in the eastern Greater Yellowstone Ecosystem, Wyoming, USA. We administered 10–30 mg of midazolam and 15 mg of azaperone intramuscularly (IM) to 32 mule deer in 2016 and 53 mule deer in 2017, and maintained a control group (captured but not sedated) of 38 mule deer in 2016 and 54 mule deer in 2017. To evaluate indicators of acute stress, we measured heart rate, blood-oxygen saturation, body temperature, respiration rate, and levels of serum cortisol. We recorded number of kicks and vocalizations of deer during handling and evaluated behavior during release. We also measured levels of fecal glucocorticoids as an indicator of baseline stress. Midazolam and azaperone did not reduce physiological, biochemical, or behavioral indicators of acute stress or influence probability of survival post-capture. Mule deer that were administered midazolam and azaperone, however, were more likely to hesitate, stumble or fall, and walk during release compared with individuals in the control group, which were more likely to trot, stot, or run without stumbling or falling. Our findings suggest that midazolam (10–30 mg IM) and azaperone (15 mg IM) may not yield physiological or demographic benefits for captured mule deer as previously assumed and may pose adverse effects that can complicate safety for captured animals, including drug-induced lethargy. Although we failed to find efficacy of midazolam and azaperone as a method for reducing stress in captured mule deer, the efficacy of midazolam and azaperone or other combinations of partial sedatives in reducing stress may depend on the dose of tranquilizer, study animal, capture setting, and how stress is defined. © 2020 The Wildlife Society.     

Effects of emersion and re-immersion on physiological and immunological variables in creel-caught and trawled Norway lobster Nephrops norvegicus

Immune defence in creel-caught and trawled Nephrops norvegicus was investigated to assess a possible relationship between phenoloxidase (PO) activation and the total haemocyte count (THC). Capture, capture method and emersion evoked physiological and immunological responses that may have implications for the ability of N. norvegicus to survive the effects of such stressors. Haemolymph THC was always negatively related to PO activity in the trawled samples, suggesting a decreased level of the plasma serine proteinase inhibitors which reportedly regulate the ProPO system (Le Moullac et al. 1998; Fish shellfish Immunol 8:621-629). In contrast, creel-caught samples showed increased levels of both PO and THC (cf. control N. norvegicus), after a 12 h emersion period. Trawling and emersion evoked progressive and significant increases (p < 0.05) in the mean levels of haemolymph L-lactate, glucose and total ammonia. The evidence of overt activity and measured haemolymph parameters suggest that creel fishing yields N. norvegicus that are more likely to survive post-harvest treatments than those that are trawled.     

Effects of helicopter net-gunning on survival of bighorn sheep

Wildlife capture, and the data collection associated with it, has led to major advancements in ecology that are integral to decision making pertaining to wildlife conservation. Capturing wildlife, however, can cause lethal and non-lethal risks to animals. Understanding the factors that contribute to the level of risk involved in wildlife capture is therefore important for the development and implementation of the safest and most effective methodologies. We used data from 736 animal captures of 389 individuals for 2 subspecies of female bighorn sheep (Rocky Mountain bighorn [Ovis canadensis canadensis], Sierra Nevada bighorn sheep [O. c. sierrae]) in Wyoming and California, USA, in 2002–2020 to evaluate the degree and extent of time that capture via helicopter net-gunning affects survival. We compared pre- and post-capture survival during a 10-week window centered on a capture event, and post-capture survival between captured animals and animals that were monitored but not captured during the 10-week window. Additionally, we evaluated the effects of handling techniques (number of times captured, season of capture event, handling time, chase time, and body temp) and biological factors (age and nutritional condition) on probability of capture mortality. Mean daily survival was 0.9992 during a 5-week pre-capture window, dropped to 0.9864 on the day of capture, and rebounded within 3 days of capture to pre-capture levels and that of sheep that were not captured. Overall, direct mortality resulting from capture was 1.36%, with 0.54% mortality occurring within the 3 days following a capture event for an overall 1.90% capture-related mortality. The only handling and biological metrics that influenced the probability of capture mortality were rectal temperature and nutritional condition; high initial rectal temperatures and poor body condition were associated with increased risk of mortality in the days following capture. Overall, helicopter net-gunning imposed low and short-term risk to survival of female bighorn sheep. To reduce bias in survival estimates, we recommend using a 3-day censorship window for post-capture mortalities as opposed to the common practice of a 2–5-week censor window. Helicopter net-gunning, including annual or seasonal recaptures, remains an effective and comparatively safe technique for capture and associated data collection of bighorn sheep.     

The effect of otolith storage methods on the concentrations of elements detected by laser-ablation ICPMS

Otoliths of male (1+ year old) Terubok, tropical shad Tenualosa toli from the Lupar River, Sarawak, were treated in different ways to assess the effect of post-capture storage on element concentrations in the otolith core and edge detected by laser-ablation inductively coupled plasma mass spectrometry (ICPMS). Five treatments were compared: rapid removal and dry storage; fish kept 5 h after capture then otoliths removed; rapid removal and stored in alcohol; fish rozen for 24 h then otoliths removed; and storage of intact head in alcohol for several weeks. Seven elements were detected at the core and edge of otoliths (Li, Na, Mg, Mn, Co, Sr, Ba). Of these, Na, Mg, Co and Ba differed among treatments, being highest in treatments where the otolith remained in the head. Variation in element measurements due to treatment effects was similar to within-otolith variation for the other elements and was least variable in the fresh treatment. The variation in concentration between the core and edge was more significant than other sources of variation (up to 100 times) for some elements. These differences were probably due to physiological factors (ontogenetic) or to yearly changes in water chemistry. The results indicate that the method of otolith storage, especially freezing whole fish, can have a small, but measurable, effect on the concentrations of Na, Mg, Co and Ba.     

Mode of death and post-mortem time effects on 3,3',5-triiodothyronine levels--relevance to elevated post-mortem T3 levels in SIDS

Post-mortem T3 levels have been reported to be increased in victims of SIDS. Recent animal studies suggest, however, that elevated T3 in SIDS may be a non-specific post-mortem phenomenon. Therefore, we studied the possible effects of post-mortem time on T3 levels in 10- and 20-day-old rats killed by various methods including: Sodium pentobarbital overdose, injection of KCl, cervical dislocation or asphyxia with 100% N, 95% N-5% CO2 or 100% CO2. In both age groups T3 remained unchanged or increased slightly when the animals were killed with Na Pentobarbital or KCl. Greater increases were observed when rats were killed by cervical dislocation or asphyxia (100% N, 95% N-5% CO2 or 100% CO2). T3 levels did not become elevated in asphyxiated adult rats in which the inferior vena cava was ligated immediately following death. By extension to the human infant, the results of this study support the possibility that elevated T3 levels in SIDS victims may result from post-mortem processes. However, these results also suggest that the post-mortem elevation in T3 levels may be directly related to the mode of death.     

Assessment of acid-base derangements among bonnethead (Sphyrna tiburo), bull (Carcharhinus leucas), and lemon (Negaprion brevirostris) sharks from gillnet and longline capture and handling methods

Blood gasses of wild bonnethead, bull, and lemon sharks were measured with the i-STAT clinical analyzer with the CG4+ cartridge immediately after capture; and again immediately prior to release after tagging, handling and morphometric measurements were taken. Relative reference ranges of post-capture status were established. Among species, stress response to capture was similar for all parameters; however, pH declined and lactate concentrations rose over time, indicating continued insult from capture and/or response to additional handling stress. pCO(2) rose faster for S. tiburo than for C. leucas, and lactate concentrations rose faster for S. tiburo than for N. brevirostris. All species caught in gillnets experienced lower pH and higher lactate concentrations than on longlines. Discriminant analysis justified the use of blood gas analysis to assess physiological stress induced by different capture methods. From these results, we recommend 1) that gear be monitored closely and sharks be removed immediately, or suboptimally, that gear is deployed for the shortest soak time possible; 2) longline over gillnet gear; and 3) extra caution with sensitive species (e.g., S. tiburo), which may include the administration of blood buffers and other therapeutics if a shark is beyond the limits of relative reference ranges reported here.     

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.     

Handling does not affect reproductive signals of male threespine stickleback

We examined the affect of handling on reproductive signal expression in male threespine stickleback, Gasterosteus aculeatus. Spectrophotometric techniques have become popular methods for measuring fish color, but the measurements require handling of the subjects in order to make measurements. Fish can undergo rapid physiological color change in response to stress. As such, handling fish may induce color changes and measured colour may not be representative of signal appearance under non-stressful conditions. We measured the reflectance characteristics of the opercular, ventro-lateral and dorso-lateral areas of 41 reproductive males from Hotel Lake, BC, Canada using spectroradiometry immediately upon capture and again at 2, 3, 4, 5, 10, 15, and 20 min post-capture. Repeated measures ANOVA revealed that post-capture handling did not affect opercular or ventro-lateral reflectance characteristics over the 20 min period. However, we did observe a change in dorso-lateral reflectance characteristics of parental males over the experiment. The results of our study show that handling does not influence reflective properties of two key components of stickleback reproductive signals during a time frame that is reasonable for taking field measurements of signal color.     

Effect of Net-Gun Capture on Survival of Mule Deer

Capture techniques to deploy radio-collars often risk mortality and injury to the animal. Capture-induced mortality can affect population sizes but also introduces bias in survival estimates based on data from captured animals. In recent years, a large-scale research and monitoring project in Utah, USA, has involved capturing and radio-collaring hundreds of mule deer (Odocoileus hemionus), a species of great interest in large parts of North America. Our objective was to investigate how the survival rates of these mule deer were affected by capture and handling. During winters of 2014–2018, an experienced capture crew net-gunned and fitted 1,805 animals with global positioning system (GPS)-collars. We estimated survival rates during the first 6 weeks after capture using Cox proportional hazard regression, and compared the survival rates of animals that were captured in a particular year to those of animals that were not captured but fitted with a GPS-collar in a previous year. We used a model selection framework to evaluate how long survival rates of captured animals were different from those of animals that were not captured. Our results indicated that weekly survival rates of captured animals were 0.985 ± 0.003 (SE), 0.988 ± 0.002, and 0.990 ± 0.001 in weeks 1, 2 and 3, respectively. Weekly survival rates of captured deer during weeks 4–6 were 0.993 ± 0.001, the same as those of deer that were not captured at the same time. Furthermore, post-capture survival rates were positively influenced by body size and negatively influenced by age. We conclude that the mortality resulting from helicopter capture was low but recommend comparing newly captured and previously captured individuals to examine what proportion of observed mortality is likely capture-related. © 2020 The Wildlife Society.     

Risk factors associated with capture-related death in eastern wild turkey hens

Capture-related mortality has been a notable risk in the handling of eastern wild turkey (Meleagris gallopavo silvestris). Our objective was to evaluate how environmental factors influence risk and identify physiological correlates that could be used to identify susceptible birds. During winter (January-March) 1995-97, 130 eastern wild turkey hens were captured in southeastern Oklahoma and radiocollared. Of those, 20 hens died < or =14 days of capture. Serum creatine kinase activity (CK; P < 0.01), body temperature (P < 0.01), processing time (P = 0.02), and ambient temperature (P < 0.01) showed a positive relationship with mortality that occurred within 14 days of capture. Plasma corticosterone concentration (P = 0.08) and relative humidity (P < 0.01) showed a negative relationship with mortalities that occurred within 14 days post-capture. Stepwise logistic regression selected CK activity, relative humidity, and ambient temperature as the best predictors of mortality within 14 days post-capture. Our data suggest that susceptible individuals may be identified from CK activity and that capture-related mortality may be minimized by establishing guidelines of when to curtail capture operations based on various weather conditions.     

Cryobiological determinants of frozen semen quality, with special reference to stallion

Success in cryopreserving stallion semen has been very variable. Several different freezing regimes have been published. However, because extenders and procedures used in each regime have differed, direct comparison of these techniques has been very difficult, and controlled studies comparing different techniques have not been reported. A number of different factors affect sperm cryosurvival. In this article we review briefly current cryopreservation procedures for stallion semen, and then in more detail cryobiological determinants of sperm function, and mechanisms of cryoinjury and cryoprotectant action. Specific attention is given to data relating to stallion sperm. The complexity of sperm cell biology is believed to be an important factor when developing improvements in stallion semen cryopreservation. It may be assumed that impairment of cell function resulting from cold and osmotic shock is a main source of stallion sperm sensitivity to conventional freezing procedures. Further physiological studies on stallion sperm are required to understand the mechanisms by which cryopreservation alters sperm function and influences selection of sperm with higher fertilizing potential. Such studies should focus especially on the processes involved in sperm volume regulation, sperm-oviduct interaction, capacitation and cellular signalling, and on the alterations in these processes caused by cryopreservation.     

Sperm quality and the morphology of cryopreserved testicular tissues recovered post-mortem from diverse wild species

This study compared the effects of slow and fast freezing of testicular tissue of wild animals collected at post-mortem on testicular structure and testicular sperm. The testes of seven animals that had died in captivity; three felids (jungle cat, lion and leopard), two cervids (rusa deer and fea’s muntjac) and two bovids (Sumatran serows) were cryopreserved using slow- and fast-freezing protocols. There were greater reductions in the integrity of the sperm membrane and DNA in tissues cryopreserved using slow freezing compared to fast freezing (membrane integrity reduced by 21.5 ± 12.4% vs. 13.0 ± 6.9%, P = 0.11 and DNA integrity reduced by 22.7 ± 16.3% vs. 6.6 ± 6.3%, P = 0.13). Histologically, there were similar degrees of detachment and shrinkage of the seminiferous tubules whereas, TUNEL assay revealed a tendency towards more apoptotic changes in the intra-tubular cells of tissues frozen using fast freezing compared to slow freezing (P = 0.09). In conclusion, fast freezing tended to cause less damage to testicular sperm but its protective effect on intra-tubular cells was likely compromised. This is the first report of gamete recovery in the wild and of the comparison in various wildlife species, between testicular tissues cryopreserved using different protocols.     

Changes in blood metabolites following stress from capture and handling of the marine teleost Girella tricuspidata

Whole blood nucleoside triphosphate (NTP) and lactate in the parore (Girella tricuspidata, Fam: Kyphosidae) were monitored over a period of 12 hr following capture by gill net. An increase in NTP during the post-capture recovery period was mainly attributable to a significant rise (P less than 0.05) in the NTP component guanosine triphosphate (GTP). The rise in GTP levels correlated with the decline in blood lactate (r = -0.72) accumulated during the period of capture stress. It is suggested that metabolism of lactate via the Krebs cycle may be responsible for the rise in GTP.     

Conservation physiology in practice: how physiological knowledge has improved our ability to sustainably manage Pacific salmon during up-river migration

Despite growing interest in conservation physiology, practical examples of how physiology has helped to understand or to solve conservation problems remain scarce. Over the past decade, an interdisciplinary research team has used a conservation physiology approach to address topical conservation concerns for Pacific salmon. Here, we review how novel applications of tools such as physiological telemetry, functional genomics and laboratory experiments on cardiorespiratory physiology have shed light on the effect of fisheries capture and release, disease and individual condition, and stock-specific consequences of warming river temperatures, respectively, and discuss how these findings have or have not benefited Pacific salmon management. Overall, physiological tools have provided remarkable insights into the effects of fisheries capture and have helped to enhance techniques for facilitating recovery from fisheries capture. Stock-specific cardiorespiratory thresholds for thermal tolerances have been identified for sockeye salmon and can be used by managers to better predict migration success, representing a rare example that links a physiological scope to fitness in the wild population. Functional genomics approaches have identified physiological signatures predictive of individual migration mortality. Although fisheries managers are primarily concerned with population-level processes, understanding the causes of en route mortality provides a mechanistic explanation and can be used to refine management models. We discuss the challenges that we have overcome, as well as those that we continue to face, in making conservation physiology relevant to managers of Pacific salmon.     

A Simple, Efficient Technique for Freezing Tetrahymena thermophila

ABSTRACT. We have developed a simple, efficient procedure for the long term freezing of Tetrahymena thermophila in liquid nitrogen. This technique yields excellent recovery of viable cells with all strains tested and does not require the use of a controlled rate low temperature freezer. To optimize the freezing technique, we have examined the effects of varying a number of parameters, including the physiological state of the cells prior to freezing, the time of exposure to cryoprotectant, and the rate of freezing and thawing. the frequency of viable cell recovery following freezing using this technique has been tested for a variety of different cell lines.     

Winter climate change implications for decomposition in northeastern forests: comparisons of sugar maple litter with herbivore fecal inputs

Forests in northeastern North America are influenced by varying climatic and biotic factors; however, there is concern that rapid changes in these factors may lead to important changes in ecosystem processes such as decomposition. Climate change (especially warming) is predicted to increase rates of decomposition in northern latitudes. Warming in winter may result in complex effects including decreased levels of snow cover and an increased incidence of soil freezing that will effect decomposition. Along with these changes in climate, moose densities have also been increasing in this region, likely affecting nutrient dynamics. We measured decomposition and N release from ¹⁵N‐labeled sugar maple leaf litter and moose feces over 20 months in reference and snow removal treatment (to induce soil freezing) plots in two separate experiments at the Hubbard Brook Experimental Forest in New Hampshire, USA. Snow removal/soil freezing decreased decomposition of maple litter, but stimulated N transfer to soil and microbial biomass. Feces decomposed more rapidly than maple litter, and feces N moved into the mineral soil more than N derived from litter, likely due to the lower C : N ratio of feces. Feces decomposition was not affected by the snow removal treatment. Total microbial biomass (measured as microbial N and C) was not significantly affected by the treatments in either the litter or feces plots. These results suggest that increases in soil freezing and/or large herbivore populations, increase the transfer rate of N from plant detritus or digested plants into the mineral soil. Such changes suggest that altering the spatial and temporal patterns of soil freezing and moose density have important implications for ecosystem N cycling.     

Effect of holding duration on the immune system of western rock lobster, Panulirus cygnus

Live holding of lobsters is a major part of the post-harvest process in lobster fisheries. Following capture, animals are placed in factory tanks and held for varying lengths of time for recovery from stress due to handling, air exposure, disturbance and environmental variations. The aim of the present study was to determine the pattern of response of a range of immune and physiological parameters over varying holding periods and assess their possible application as a measure of recovery from stress of post-harvest procedures and in the determination of an appropriate duration of acclimation prior to live transport. The effect of holding duration on the following immune parameters: total haemocyte counts (THC), haemolymph clotting times, haemolymph pH, haemolymph protein concentration and the differential proportion of haemocytes, was assessed. Lobsters brought to the factory were placed in holding tanks and sampled over a period of up to 10 days. Two studies were conducted, the first on lobsters from different catch groups and the second on lobsters from the same day's catch from the same area. Experiments were conducted on adult animals (10-12 animals/treatment group) with a different group of lobsters being sampled at each time point. Various immune parameters showed alterations with time during holding. A consistent observation was significantly prolonged clotting times following four days of holding. The haemolymph pH showed a strong positive correlation to clotting time and the hyaline cell proportion showed a strong negative correlation with semi-granular cells. Although the levels of THC, clotting time and differential cell counts after one day of holding were similar to those observed in other studies on rested post-harvest lobsters, suggesting that the lobsters had recovered from the acute stress of capture and transport, subsequent alterations in pH, clotting time and differential cell counts indicated other physiological adjustments were still occurring for up to 4 days post capture. Overall the results suggest that though the effects of post-harvest procedures on the immune parameters appear to be resolved after a short duration of holding at low temperatures, no single immune parameter can provide predictable indication of the acclimation process.     

Targeted resequencing of a genomic region influencing tameness and aggression reveals multiple signals of positive selection

The identification of the causative genetic variants in quantitative trait loci (QTL) influencing phenotypic traits is challenging, especially in crosses between outbred strains. We have previously identified several QTL influencing tameness and aggression in a cross between two lines of wild-derived, outbred rats (Rattus norvegicus) selected for their behavior towards humans. Here, we use targeted sequence capture and massively parallel sequencing of all genes in the strongest QTL in the founder animals of the cross. We identify many novel sequence variants, several of which are potentially functionally relevant. The QTL contains several regions where either the tame or the aggressive founders contain no sequence variation, and two regions where alternative haplotypes are fixed between the founders. A re-analysis of the QTL signal showed that the causative site is likely to be fixed among the tame founder animals, but that several causative alleles may segregate among the aggressive founder animals. Using a formal test for the detection of positive selection, we find 10 putative positively selected regions, some of which are close to genes known to influence behavior. Together, these results show that the QTL is probably not caused by a single selected site, but may instead represent the joint effects of several sites that were targets of polygenic selection.