Welcome to this months peer reviewed science. Lots of new science to educate and inform your work 🙂
Curry, Erin, et al. “Integrating trans‐abdominal ultrasonography with fecal steroid metabolite monitoring to accurately diagnose pregnancy and predict the timing of parturition in the red panda (Ailurus fulgens styani).” Zoo Biology (2017).
Red pandas (Ailurus fulgens styani) exhibit a variable gestation length and may experience a pseudopregnancy indistinguishable from true pregnancy; therefore, it is not possible to deduce an individual’s true pregnancy status and parturition date based on breeding dates or fecal progesterone excretion patterns alone. The goal of this study was to evaluate the use of transabdominal ultrasonography for pregnancy diagnosis in red pandas. Two to three females were monitored over 4 consecutive years, generating a total of seven profiles (four pregnancies, two pseudopregnancies, and one lost pregnancy). Fecal samples were collected and assayed for progesterone (P4) and estrogen conjugate (EC) to characterize patterns associated with breeding activity and parturition events. Animals were trained for voluntary transabdominal ultrasound and examinations were performed weekly. Breeding behaviors and fecal EC data suggest that the estrus cycle of this species is 11–12 days in length. Fecal steroid metabolite analyses also revealed that neither P4 nor EC concentrations were suitable indicators of pregnancy in this species; however, a secondary increase in P4 occurred 69–71 days prior to parturition in all pregnant females, presumably coinciding with embryo implantation. Using ultrasonography, embryos were detected as early as 62 days post-breeding/50 days pre-partum and serial measurements of uterine lumen diameter were documented throughout four pregnancies. Advances in reproductive diagnostics, such as the implementation of ultrasonography, may facilitate improved husbandry of pregnant females and allow for the accurate prediction of parturition.
Nelson Slater, Melissa, and Mark E. Hauber. “Olfactory enrichment and scent cue associative learning in captive birds of prey.” Zoo Biology (2017).
As the use of enrichment in zoos has become a standardized husbandry practice, the continued improvement of enrichment programs should be concomitant with empirical validation of those practices. The role of scent as enrichment remains an unexplored avenue for many bird species. We conducted a multi-phase experiment to introduce wrapped food packages and scent cuing to indicate food presence into the exhibits of several birds of prey species at the Bronx Zoo, New York City, to assess if scent can function as enrichment in these species. Our research found support for these birds associating a novel scent cue from a package with the presence of food inside. When tested with sham (empty) packages, these individuals more often and more extensively handled scented versus unscented packages. Overall, these results indicate the ability of some our small sample of individuals to learn olfactory cues and provide support for trials to include olfactory enrichment as a potential part of the daily routine for some birds of prey in zoo settings.
Byrne, Phillip G., and Aimee J. Silla. “Testing the effect of dietary carotenoids on larval survival, growth and development in the critically endangered southern corroboree frog.” Zoo Biology (2017).
The success of captive breeding programs (CBPs) for threatened species is often limited due to a lack of knowledge of the nutritional conditions required for optimal growth and survival. Carotenoids are powerful antioxidants known to accelerate vertebrate growth and reduce mortality. However, the effect of carotenoids on amphibian life-history traits remains poorly understood. The aim of our study was to use a manipulative laboratory experiment to test the effect of dietary-carotenoid supplementation during the larval life stage on the survival, growth and development of the critically endangered southern corroboree frog (Pseudophryne corroboree). Larvae were fed either a carotenoid supplemented diet or an unsupplemented diet and the survival, growth and development of individuals was monitored and compared. There was no significant effect of dietary treatment on larval survival, growth rate, time taken to reach metamorphosis, or body size at metamorphosis. Our findings provide no evidence that carotenoid supplementation during the larval life stage improves the growth and development of southern corroboree frogs. However, because the carotenoid dose used in our study did not have any detrimental effects on P. corroboree larvae, but has previously been shown to improve adult coloration, immunity, and exercise performance, carotenoid supplementation should be considered when evaluating the nutritional requirements of P. corroboree in captivity. Carotenoid supplementation studies are now required for a diversity of anuran species to determine the effects of carotenoids on amphibian survival, growth and development. Understanding the effects of dietary carotenoids on different life-history traits may assist with amphibian captive breeding and conservation.
Price, Eluned C., Louise A. Ashmore, and Anne‐Marie McGivern. “Reactions of zoo visitors to free‐ranging monkeys.” Zoo Biology 13.4 (1994): 355-373.
The lack of appropriate stimuli associated with captive environments has been documented to cause several behavioural and physiological issues in captive species, including loss of natural behaviours, psychopathologies and decreased reproductive success. Providing free-ranging, naturalistic exhibits that replicate elements of a species’ natural environment is advocated as a means of promoting and preserving the natural behavioural repertoire in captive species. Exhibition of natural behaviour is considered beneficial to conservation in terms of animal health and welfare, reintroduction success, education and research. This study assessed differences in behaviour of emperor and pied tamarins housed in free-ranging and caged exhibits at Durrell Wildlife Park, to determine the impact of exhibit type. Free-ranging tamarins were expected to exhibit a repertoire of behaviours more similar to that of wild tamarins based on their access to a more naturalistic and complex environment. Data was collected on a variety of behaviours, including activity, substrate use and communication, using instantaneous and one-zero sampling at 30 s intervals. Findings indicated that both free-ranging and caged tamarins exhibited natural behaviours; however, there were significant differences in mean rates of behaviours between conditions. Free-ranging tamarins exhibited significantly higher rates of locomotion (emperors: P < 0.001; pieds: P < 0.001), long calls (pieds: P = 0.019) and alarm calls (emperors: P = 0.012), and displayed competent use of the environment in terms of natural substrate use (emperors: P < 0.001; pieds: P = 0.007) and interspecific interactions. Caged tamarins exhibited significantly higher rates of affiliative (emperors: P = 0.001; pieds: P = 0.026) and agonistic (emperors: P = 0.003) intraspecific interactions and time spent in contact (emperors: P = 0.048; pieds: P = 0.043), which was largely attributed to spatial restrictions imposed by caged exhibits. This study, consistent with existing literature, indicated that the free-ranging exhibit was conducive to the expression of a behavioural repertoire more similar to that of wild tamarins. This was probably a result of the increased behavioural opportunities available in the free-ranging exhibit, highlighting their importance in promoting wild-type behaviours. However, some mean rates of behaviour were still noticeably less than those documented in wild counterparts. Methods to further promote natural behaviours in both exhibits are recommended to facilitate ex situ and in situ conservation efforts.
Moszuti, Sophie A., Anna Wilkinson, and Oliver HP Burman. “Response to novelty as an indicator of reptile welfare.” Applied Animal Behaviour Science (2017).
Whilst a great deal of research has been focused on identifying ways to assess the welfare of captive mammals and birds, there is comparatively little knowledge on how reptilian species are affected by captivity, and the ways in which their welfare can be accurately assessed. The present study investigated response to novelty – a commonly used approach to assess anxiety-like behaviour and hence welfare in non-human animals – in two species of reptile with the aim of determining whether this approach could be successfully translated from use in mammalian and avian species for use in reptiles, and whether we could also identify reptile-specific and/or species-specific behaviours. Eight red-footed tortoises (Chelonoidis carbonaria) and seventeen bearded dragons (Pogona vitticeps) were observed individually in both familiar and novel environments for 10 minute time periods, and their behaviour recorded. Tortoises were found to begin locomotion sooner when placed in a familiar environment than when placed in a novel environment, they extended their necks further in a familiar environment and their neck length increased over time in both familiar and novel environments, suggesting an overall anxiety-like response to novelty as seen in non-reptilian species. In contrast, whilst bearded dragons exhibited significantly more tongue-touches in a novel, compared to a familiar, environment, they showed no difference between familiar and novel environments in their latency to move. This result suggests that, whilst the dragons appeared to discriminate between the two environments, this discrimination was not necessarily accompanied by an anxiety-like response. This study has confirmed the translatability of response to novelty as an approach to assess anxiety-like behaviour in one species of reptile, as well as identifying species-specific behaviours that have the potential to be used in future studies when assessing the welfare of reptiles in response to captive environments, but our results also highlight the need to be aware of species differences within a class as diverse as reptilia.
Jones, Stephanie K. Courtney, Adam J. Munn, and Phillip G. Byrne. “Effects of captivity on house mice behaviour in a novel environment: Implications for conservation practices.” Applied Animal Behaviour Science 189 (2017): 98-106.
Captive breeding programmes offer a method for preventing the extinction of threatened species, but often have difficulty establishing self-sustaining populations and generating individuals for release. This difficulty can arise because the behaviour of captive-reared animals differs from wild animals. Whilst the effect of captivity on animal behaviour has been widely reported, few studies have explicitly compared differences between captive-reared and wild-caught animals. Even fewer have examined behavioural types (a composition of behavioural traits) displayed in novel environments, which is particularly relevant for determining reintroduction success. Further, the transgenerational effects on behavioural type, and potential differences between sexes in response to captivity, remain almost completely unknown. Using house mouse (Mus musculus) as a model for small mammals, we tested whether behavioural types displayed in a novel environment differed between captive-reared and wild-caught animals. In addition, it was tested whether behavioural types were subject to transgenerational effects in captivity, and whether there were sex-specific differences in behavioural types. We used an open field test to simulate a novel environment. Captive-reared mice were found to differ in their boldness and activity behavioural type compared to their wild-caught mice (p < 0.001). There was marginal evidence for transgenerational effects on behavioural type in captivity, but three behavioural traits displayed a shift away from wild behaviours (% Time active: p < 0.001; % Time mobile: p = 0.004; Centre: maximum speed: p = 0.004). Furthermore, behavioural types of individuals in captivity did not differ depending on sex (F0: p = 0.161; F1: p = 0.665), however behavioural type did differ between wild-caught females and males (p = 0.015). These findings suggest that captivity can result in behavioural changes and loss of sex-specific behaviours. In addition, phenotypic plasticity may have a significant influence on behavioural type. This knowledge may be critical for developing methods to improve small mammal reintroduction programmes.
Rose, Paul E., and Darren P. Croft. “Social bonds in a flock bird. Species differences and seasonality in social structure in captive flamingo flocks over a 12-month period.” Applied Animal Behaviour Science (2017).
Social network analysis (SNA) is a popular tool for investigating key components of sociality in free-living populations, and is growing in its application to captive animal systems. For social species held in captivity, welfare may be improved if protocols for care take key aspects of sociality into account. Individuals may benefit from investment in social affiliations and these relationships may exist over many years. Here we examine patterns of association that exist within captive flamingo (Phoenicopteridae) flocks across a 12-month period. We test the hypotheses that birds will show stable bonds with specific individuals within a flock, and that these bonds will be stable over time. Flamingos are well known for being highly-gregarious birds yet the importance of specific relationships between birds in a flock is still poorly defined. Four flocks of captive flamingos, of five species were included in the study at WWT Slimbridge Wetland Centre to assess the strength and consistency of bonds between individuals. Social associations were scored for all flocks from March 2012 to March 2013, with an average of 98 days/sample time/flock. Each flock showed evidence of specific preferential associations between birds, which, in some cases, remained constant over the period of observations. Networks highlight the existence of inter- and intrasexual bonds present in all flamingo flocks. Mantel tests determine that strong dyadic bonds are maintained in (spring/summer) and out (autumn/winter) of the breeding season. Measuring social behaviour may provide an insight into flamingo welfare as changes in the number of associates and mean time spent associating appears to be impacted upon by environmental variables, such as enclosure type. As consistent partnerships are maintained between birds (of all flocks of all species) across season, there are potential implications for breeding and mate selection if new partnerships are not being formed at breeding times.
Kohari, Daisuke, et al. “Behavioral restriction effects on activity motivation of a captive lion (Panthera leo persica).” Journal of Veterinary Behavior: Clinical Applications and Research 17 (2017): 14-18.
It has been suggested that the locomotive needs of zoo animals are not always satisfied in captive conditions. However, these reasons for movement and locomotion differ among species. This study investigated the locomotive motivation of captive lions, which are regarded as having relatively low motivation to move compared to other zoo animals. Four Indian lions including 1 noncastrated male and 3 females were observed as subject animals. Two captive conditions were set as experimental days: 1 was a confined condition in a bed chamber all day long (confined day); another was a released condition, with access to the exhibition area during daytime (released day). The observation periods were also defined as “daytime” (9:00-16:00) and “nighttime” (16:30-9:00 of the next morning). We counted the lions’ behavior repertories and recorded their maintenance, social, reproductive, and abnormal pacing behavior of 24 hours each day 5 times from the beginning of August to the end of November. Results show no difference in the numbers of behavior repertories between the released and confined days (chi(2)=0.084, NS), suggesting that the conditions in this zoo might be sufficient for captive lions to express various behavior repertories. However, the maintenance behavior percentages were significantly different when confined and released days were compared (daytime, chi(2) = 19.17, P < 0.01; nighttime, chi(2) = 13.06, P < 0.05). All the lions rested nearly all day long except around evening housing time or in the morning on the released days. However, on confined days, they were usually restless. Furthermore, abnormal pacing during walking (chi(2) = 3.94, P < 0.05) was significantly different on each day. These results suggest that the lion’s locomotor needs were not satisfied when the lions were confined in the bed chamber all day, even though they did not always move actively. It might be important for the lions to have some opportunity to ramble.
Ozella, L., et al. “Effect of weather conditions and presence of visitors on adrenocortical activity in captive African penguins (Spheniscus demersus).” General and comparative endocrinology (2015).
A number of potential stressors are present in captive environments and it is critically important to identify them in order to improve health and welfare in ex situ animal populations. In this study, we investigated the adrenocortical activity of a colony of African penguins hosted in an immersive zoo in Italy, with respect to the presence of visitors and local microclimatic conditions, using the non-invasive method of assessing faecal glucocorticoid metabolites (FGMs). The penguins’ exhibit is a large naturalistic outdoor enclosure, which closely reproduces the natural habitat of this species. Data collection took place from the beginning of June to the end of August 2014, during the period of maximum flow of visitors. We carried out 12 sampling periods, each involving 2 consecutive days; during the first day we counted the visitors and we registered the meteorological data, and on the second day, we collected the faecal samples, which amounted to a total of 285 faecal samples. Our results showed that the number of visitors did not influence the adrenocortical activity of the African penguins. Conversely, the local microclimatic conditions did influence the physiological stress on these birds. We found that an increase of the daily mean temperature induced a significant increase in FGM concentrations, although humidity and wind speed had a moderating effect on temperature and reduced the heat-induced stress. Moreover, we calculated two climatic indices, commonly used to assess the thermal discomfort in animals, namely the THI (Temperature-Humidity Index) and WCI (Wind Chill Index), and we detected a positive relationship between their values and the FGM levels, demonstrating that these indices could be useful indicators of weather discomfort in African penguins. Our study shows that the simulating naturalistic conditions could have significant benefits for zoo animals, such as reducing the negative effect of visitors. Nevertheless, it should be taken into account where the zoological facility is located and if the local microclimatic conditions are compatible with the hosted species, to ensure that they do not differ greatly from their natural habitat.
Krebs, Bethany L., et al. “Applying Behavioral Conditioning to Identify Anticipatory Behaviors.” Journal of Applied Animal Welfare Science (2017): 1-21.
The ability to predict regular events can be adaptive for nonhuman animals living in an otherwise unpredictable environment. Animals may exhibit behavioral changes preceding a predictable event; such changes reflect anticipatory behavior. Anticipatory behavior is broadly defined as a goal-directed increase in activity preceding a predictable event and can be useful for assessing well being in animals in captivity. Anticipation may look different in different animals, however, necessitating methods to generate and study anticipatory behaviors across species. This article includes a proposed method for generating and describing anticipatory behavior in zoos using behavioral conditioning. The article also includes discussion of case studies of the proposed method with 2 animals at the San Francisco Zoo: a silverback gorilla (Gorilla gorilla gorilla) and a red panda (Ailurus fulgens). The study evidence supports anticipation in both animals. As behavioral conditioning can be used with many animals, the proposed method provides a practical approach for using anticipatory behavior to assess animal well being in zoos.
Is music enriching for group-housed captive chimpanzees (Pan troglodytes)?
Emma K. Wallace, Drew Altschul, Karoline Körfer, Benjamin Benti, Amanda Kaeser, Susan Lambeth, Bridget M. Waller, Katie E. Slocombe
Many facilities that house captive primates play music for animal enrichment or for caregiver enjoyment. However, the impact on primates is unknown as previous studies have been inconclusive. We conducted three studies with zoo-housed chimpanzees (Pan troglodytes) and one with group-housed chimpanzees at the National Centre for Chimpanzee Care to investigate the effects of classical and pop/rock music on various variables that may be indicative of increased welfare. Study one compared the behaviour and use of space of 18 animals when silence, classical or pop/rock music was played into one of several indoor areas. Overall, chimpanzees did not actively avoid the area when music was playing but were more likely to exit the area when songs with higher beats per minute were broadcast. Chimpanzees showed significantly fewer active social behaviours when music, rather than silence, was playing. They also tended to be more active and engage in less abnormal behaviour during the music but there was no change to either self-grooming or aggression between music and silent conditions. The genre of music had no differential effects on the chimpanzees’ use of space and behaviour. In the second study, continuous focal observations were carried out on three individuals with relatively high levels of abnormal behaviour. No differences in behaviour between music and silence periods were found in any of the individuals. The final two studies used devices that allowed chimpanzees to choose if they wanted to listen to music of various types or silence. Both studies showed that there were no persistent preferences for any type of music or silence. When taken together, our results do not suggest music is enriching for group-housed captive chimpanzees, but they also do not suggest that music has a negative effect on welfare.
Aquaculture – April 2017 Volume 473
Pereira A., Carvalho A.P., Cruz C., Saraiva A., (2017) Histopathological changes and zootechnical performance in juvenile zebrafish (Danio rerio) under chronic exposure to nitrate, Aquaculture, 473:197-205, http://dx.doi.org/10.1016/j.aquaculture.2017.02.018
Abstract: Zebrafish is currently intensively reared in laboratories around the world due to its increasing importance as an experimental model in biomedical research. Recirculating aquaculture systems (RAS) have been generally used for zebrafish rearing, allowing the maintenance of high densities of fish with minimal water renewal. Biofilters play a pivotal role in RAS by converting the highly toxic ammonia excreted by fish into nitrate. Due to its much lower acute toxicity, nitrate accumulation in RAS is usually neglected, and fish can be exposed to relatively high levels of this compound for extended periods. This study evaluated the impact of chronic exposure to relevant levels of nitrate on the zootechnical performance and histology of selected organs (gills, integument, kidney, liver, and intestine) of juvenile zebrafish, with the aim to define safety levels of this nitrogenous compound for zebrafish rearing. For that, groups of 30-day-old zebrafish were exposed to < 7 (control), 100, 200, and 400 mg L− 1 nitrate-N for 28 days. No mortality was registered in fish exposed up to 200 mg L− 1 nitrate, and all individuals seemed externally healthy; however, in fish exposed to the highest nitrate concentration mortality reached 47% at the end of the trial, and many individuals showed lethargy, abnormal swimming, emaciation, lordosis, and/or superficial lesions. Although final growth was not significantly different among groups, growth parameters tend to decrease with increasing levels of nitrate, and a significant negative correlation was found between weight gain and nitrate levels, suggesting a dose-dependent negative effect of nitrate on growth. Except for the lowest nitrate concentration (100 mg L− 1 nitrate-N), the histological survey revealed significant changes induced by nitrate in all examined organs, and a dose-dependent effect of nitrate on the overall histopathological changes is suggested. In conclusion, this study shows that the chronic exposure of zebrafish juveniles to nitrate induces histopathological changes that would lead to a negative impact on the general health condition of fish. Fish growth tended to decrease and the overall histological damages tended to increase with increasing nitrate levels, particularly above 100 mg L− 1(the lowest tested value). Thus, we recommend that this limit of 100 mg L− 1 nitrate-N should not be exceeded in RAS during rearing of juvenile zebrafish.
North American Journal of Aquaculture – April 2017 Volume 79
Cupp A.R, Schreier T.M., Schleis S.M., (2017), Live Transport of Yellow Perch and Nile Tilapia in AQUI-S 20E (10% Eugenol) at High Loading Densities, N.American Jnl of Aquaculture, 79:176-182
Abstract: Fish transport costs are a substantial portion of the operational expenses for aquaculture facilities in the USA. Safely transporting higher loading densities of fish would benefit haulers by increasing efficiency and reducing costs, but research evaluating transport for individual species is generally lacking. In this study, Yellow Perch
Perca flavescens and Nile Tilapia Oreochromis niloticus were transported for 6 h immersed in water containing AQUI-S 20E (10% eugenol) at fish loading densities of 240 g/L (2 lb/gal) for perch and 480 g/L (4 lb/gal) for tilapia. Survival was quantified for fish transported in AQUI-S 20E concentrations of (1) control or 0 mg/L of water, (2) 100 mg/L, or (3) 200 mg/L. Yellow Perch had 98–100% survival, and Nile Tilapia had 100% survival up to through 14 d after transport across all AQUI-S 20E levels, including the control.Eugenol concentrations decreased rapidly in transport tank water, and fish showed no signs of sedation by the end of transport.We conclude that live transport of Yellow Perch and Nile Tilapia at higher loading densities resulted in high survival regardless of the AQUI-S 20E concentrations we tested.
March 2017 Volume 13 Issue 2
Kousteni V., Karachle P.K., & Megalofonou P., (2017). Diet of the small-spotted catshark Scyliorhinus canicula in the Aegean Sea (eastern Mediterranean), Marine Biology Research, 13:2 161-173, http://dx.doi.org/10.1080/17451000.2016.1239019
Abstract: The diet of the small-spotted catshark Scyliorhinus canicula, captured in the Aegean Sea by bottom-trawl from 2006 to 2012, was investigated with respect to sex, maturity condition, sampling location and season. The stomach contents of 432 specimens, measuring from 144 to 517 mm in total length, were analysed. The cumulative prey curve showed that the sample size was adequate to describe the species’ diet, which was quantified using the percentage gravimetric composition (%W). The identified prey items belonged to eight major groups: Teleostei, Chondrichthyes, Crustacea, Cephalopoda, Annelida, Echinodermata, phanerogams and macroalgae, with Teleostei, Crustacea and Cephalopoda being the most consumed in both females (%W= 48.1, 16.0 and 31.4, respectively) and males (%W= 33.9, 31.6 and 29.8, respectively). Higher diet diversity was observed in males than females, in immature individuals than mature ones, regardless of sex, as well as in spring in comparison to autumn and winter. Feeding intensity seemed to be influenced mainly by sex and maturity condition. No significant dietary overlap was observed for all possible combinations
of the factors examined. Gut indices were compared between the two sexes with females showing statistically significantly higher median relative gut length, as well as a longer gut than males of the same length. Based on the diet composition, S. canicula can be considered a generalist predator consuming, with geographical differentiation, a wide variety of benthic taxa. The estimated fractional trophic level (τ = 4.22) classified the species as a carnivore with a preference for Teleostei and Cephalopoda, thus confirming its key role in the food web.
Ichthyological Research– January 2017 Volume 64 Issue 1
Satoh S., Tanoue H., Ruitton S. (2017) Morphological and behavioral ontogeny in larval and early juvenile discus fish Symphysodon aequifasciatus, Ichthyol Res, 64:1 37-44. doi:10.1007/s10228-016-0530-y
Abstract: We observed the growth, morphological changes, and behavior of larvae and juveniles of the Amazonian substrate-brooding cichlid discus fish Symphysodon aequifasciatus under laboratory conditions. The mean body length (BL) of newly hatched larvae was 3.4–3.5 mm, and the yolksac extended to approximately 42 % of their BL. Larvae detached from the substrate on day 4 began swimming and immediately displayed biting behavior on the body surface of the parents. Larvae had completely consumed their yolksacs by day 7. They began swimming at an earlier developmental stage compared with other cichlid species. Their thick lips may be advantageous for removing mucus from the bodies of the parent fish. Juveniles actively fed on Artemia spp. by day 30, and the frequency of biting behavior toward the parents decreased between days 20 and 35. Bone ossification was essentially complete in juveniles by day 32. Juveniles reached 16.0 ± 1.1 mm BL by day 35. These results indicate that the morphology and behavior of larval and early juvenile S. aequifasciatus exhibit adaptations for mucus provisioning.
Journal of Experimental Marine Biology and Ecology- June 2017 Volume 491
Lim C.S., Bachok Z., Hii Y.S, (2017), Effects of supplementary polyunsaturated fatty acids on the health of the scleractinian coral Galaxea fascicularis (Linnaeus, 1767), Jnl of Exp Mar Biol and Ecol., 491:1-8, http://dx.doi.org/10.1016/j.jembe.2017.02.009
Abstract: Polyunsaturated fatty acids (PUFAs) are essential for stress recovery in corals. By examining changes in the PUFA composition of stony coral, Galaxea fascicularis (Linnaeus, 1767), the present study investigated whether exogenous PUFAs can be retained by corals and improve coral health following heterotrophic feeding. G. fascicularis was fed either PUFA-enriched or non-enriched Artemia sp. for 1, 2, 5, and 10 weeks, and starved corals were used as the control. The first 1–2 weeks were found to be the adjustment period for assimilating PUFAs; during this period, there was no significant difference in fatty acid content among the treatment groups. However, after 5 weeks of enrichment, the corals that were fed PUFA-enriched Artemia had increased their fatty acid content to a plateau of 32% of the total lipids. Fed corals had both higher photosynthetic and respiration rates in the experiment. The fed corals also had a lower ratio of saturated fatty acid (SAFA):PUFA than those in the control group after 5 weeks of feeding. The corals fed PUFA-enriched Artemia also contained higher levels of ω3 and ω6 PUFAs. G. fascicularis fed PUFA-enriched Artemia had a higher level of eicosapentaenoic acid (20:5), which is widely reported to be synthesized by the coral’s symbiotic zooxanthellae. The increased zooxanthellae density and chlorophyll content in the PUFA-enriched corals indicated that this group had improved health, suggesting that PUFA enrichment has a positive feedback effect on autotrophy in G. fascicularis, benefiting their overall
Fujimura A.G., Riegl B.M., (2017) Effects ofwater flowon intra- and intercolonial variability in bleaching of the zoanthid, Palythoa caribaeorum, Jnl of Exp Mar Biol and Ecol., 491:29-33, http://dx.doi.org/10.1016/j.jembe.2017.02.006
Abstract: The zoanthid, Palythoa caribaeorum, is a good indicator of coral bleaching because it is highly susceptible to bleaching under physiological stresses. We show that water flow accounts for variation in thermal bleaching sensitivity of P. caribaeorum within and between colonies. Sample colonies were exposed to two flow regimes (low = 3 cm s− 1; high = 15 cm s− 1) and two temperature regimes (low = 26.5 °C; high = 33.5 °C) in a unidirectional flume for 48 h. Six individual colonies of two sizes (small = 2.3 ± 0.2 cm; large = 7.3 ± 0.4 cm in diameter) were tested per flow regime. Degrees of bleaching were measured by zooxanthellae count and chlorophyll a concentration. Bleaching of P. caribaeorum was induced by high temperature. High water flow mitigated bleaching, but there was considerable variation in bleaching within and between colonies. Upstream sides of large colonies bleached less than downstream sides in high flow. High water flow also moderated bleaching of small colonies more than large colonies. One possible explanation for these results is that high mass transfer rates mitigate bleaching. This may be more easily accomplished in small colonies, in which the entire colony tends to be exposed to high water flow; thus, small colonies have an advantage during bleaching events.