Increased noise levels cause behavioural and distributional changes in Atlantic cod and saithe in a large public aquarium—a case study

Investigating the effects of underwater noise on aquatic animals is a research field that is receiving rapidly increasing attention. Despite this, surprisingly few studies have addressed the potential impacts of noise in a marine animal husbandry setting. In this regard, the behaviour of fish in public aquariums can be used as an indicator of well-being, and noise is known to cause behavioural changes. This case study investigates the behaviour of cod (Gadus morhua) and saithe (Pollachius virens) in a large public aquarium when exposed to increased noise levels originating from an aquarium renovation carried out by construction divers. Swimming behaviour, group formation and vertical distribution, along with yawning and scratching frequencies of the fish, were analysed from video recordings made before, during and after the exposure to increased noise levels. The same parameters were also analysed to evaluate potential effects of the presence of divers when not making renovation noise, compared to fish behaviour prior to the renovation. There was a slight change in the depth distribution of both species and a decrease in the number of scratches in cod due to the presence of divers that were not making renovation noise. In the presence of construction noises in the tank, however, both cod and saithe showed a wider array of behavioural changes, including increased swimming speed, changes in depth distribution and increased yawning frequencies. The results from this case study demonstrate that an underwater renovation with increased noise levels impacts fish behaviour and suggests that underwater noise should be considered during the management of aquatic environments, including public aquaria

Sexual signalling and noise pollution - implications for courtship behaviour and reproductive success in two vocal species of marine gobies

Many marine animals use acoustic signals to mediate social interactions. Acoustic cues and signals are especially important in water because sound is unique as a sensory modality propagating with little attenuation over long distances, at all depths, and irrespective of the water current direction. Anthropogenic underwater noise is a global pollutant of increasing concern but its impact on reproduction in fish is largely unknown. Hence, a better understanding of this important link to fitness is crucial. Here, I compared different courtship traits, including courtship sounds, in two sympatric Pomatoschistus species and I found that courting males of the common goby Pomatoschistus microps sing louder and produce sounds of shorter duration than males of the sand goby Pomatoschistus minutus. Furthermore, eyes of P. minutus females turn black during courtship attempts, whereas this is not the case for females of P. microps. Dark eyes in females of P. minutus were more likely to be displayed by more gravid females, but males did not respond behaviourally or preferred dark-eyed females. I suggest that dark eyes are not a signal per se but may be an aspect of female mate choice, possibly related to vision. Furthermore, I examined if an experimentally altered body condition in P. minutus males affects acoustic and visual display and if it influences females’ decision to spawn or not. Visual and acoustic courtship and reproductive success was studied under two experimental food regimes (high food and low food) and compared to a control group (fish from the field). Condition did not affect visual or acoustic courtship, nor did it affect mating success. Females only spawned with males that produced sound and courtship sounds are likely to be important in female mate choice. To further understand how anthropogenic noise can affect mating success by masking the acoustic cue, I experimentally tested the impact of broadband noise exposure on the behaviour and reproductive success of P. microps. Noise treatment had similar frequency range as anthropogenic boat noise and was presented either continuously or intermittently. The continuous noise treatment had the most detrimental effect by reducing spawning probability, whereas male nest-building behaviour and active pre-spawning behaviour (including courtship) were unaffected. Additionally, females took longer to spawn under continuous noise than in the control. Egg density was significantly higher in both noise treatments compared to the control. Since sexual selection can be sensitive to changes in the environment I also investigated effects of noise on male mating success in P. minutus. I compared no added noise (‘silence’) to added artificial Brownian noise to create disturbance at moderate levels. In silent condition, successful males were significantly larger than unsuccessful males, which was not the case in the noise treatment. More males received eggs in the silent treatment compared to the noise treatment, creating a relaxed opportunity for sexual selection in the silent environment. However, here was no significant effect of treatment on the number of spawned eggs. The results suggest that disturbance caused by noise can influence mating decisions and traits under sexual selection. In conclusion, in this thesis I show that noise, particularly a continuous noise exposure, negatively affects reproductive success, highlighting its potential to impact fish demography. Future studies in natural conditions are required for a better understanding of the impact of noise on fish reproduction. Thus, I suggest that aquaria studies should be performed in a low noise environments, since noise clearly can affect the outcome of an experimental result

Acoustic and visual courtship traits in two sympatric marine Gobiidae species - Pomatoschistus microps and Pomatoschistus minutus

Divergence in courtship traits across species can evolve as adaptations to different environments, and also through avoidance of reproductive interference and character displacement. Differences may also be explained by phylogenetic relationships. We compared different courtship traits, including male courtship sounds, in two sympatric Pomatoschistus species. Both species are characterised by having male and female courtship, and paternal care of eggs in nests under mussel shells and rocks. In addition to presenting novel observations, we reviewed the literature on courtship traits for both species and complemented it with new observations. We found that courting males of the common goby P. microps sing louder and produce sounds of shorter duration than males of the sand goby P. minutus. Furthermore, males of P. microps swim faster towards females during courtship than males of P. minutus. The eyes of P. minutus females turn black during courtship attempts, whereas this is not the case for females of P. microps. Species-specific differences in courtship sounds and behavior may lead to different susceptibility of the two species to environmental change such as noise pollution and turbidity

Sand goby females do not spawn with silent males - but do males sing out their condition and can female hear the song in a noisy environment?

Males of sand gobies (Pomatoschistus spp.) spawn in shallow water and produce a courtship sound to entice females to spawn. Previous work on field-caught males shows that courtship sounds differ between males of different body condition and between species suggesting that females use acoustic information in mate choice. Here, we manipulated male body condition via feeding regimes and measured courtship and subsequent spawning decisions. Although male condition measured as lipid content differed significantly between feeding regimes, neither male visual courtship, acoustic courtship nor spawning success were affected. However, comparing the lipid content of the experimental males to field-caught males show that in nature, males are of similar condition to males in the low condition treatment group. Acoustic signals might be masked by anthropogenic noise. Thus, to test if noise may affect spawning success we exposed courting males to experimental noise, resembling boat noise. We found that females only spawned with males that produced courtship sounds and significantly less often when exposed to noise. We conclude that the information content of male courtship sound and how it relates to male condition remains elusive, but that acoustic courtship is essential for mating success, making sand gobies potentially vulnerable to noise pollution. These results will be discussed in the light of preliminary data from a field experiment using the same noise set-up where male mating success was unaffected by treatment, and a pond experiment where variation in male mating success was affected by low levels of playback noise

Sand goby females do not spawn with silent males - but do males sing out their condition and can female hear the song in a noisy environment?

Males of sand gobies (Pomatoschistus spp.) spawn in shallow water and produce a courtship sound to entice females to spawn. Previous work on field-caught males shows that courtship sounds differ between males of different body condition and between species suggesting that females use acoustic information in mate choice. Here, we manipulated male body condition via feeding regimes and measured courtship and subsequent spawning decisions. Although male condition measured as lipid content differed significantly between feeding regimes, neither male visual courtship, acoustic courtship nor spawning success were affected. However, comparing the lipid content of the experimental males to field-caught males show that in nature, males are of similar condition to males in the low condition treatment group. Acoustic signals might be masked by anthropogenic noise. Thus, to test if noise may affect spawning success we exposed courting males to experimental noise, resembling boat noise. We found that females only spawned with males that produced courtship sounds and significantly less often when exposed to noise. We conclude that the information content of male courtship sound and how it relates to male condition remains elusive, but that acoustic courtship is essential for mating success, making sand gobies potentially vulnerable to noise pollution. These results will be discussed in the light of preliminary data from a field experiment using the same noise set-up where male mating success was unaffected by treatment, and a pond experiment where variation in male mating success was affected by low levels of playback noise

In-Hospital Delays in Stroke Thrombolysis : Every Minute Counts

BACKGROUND AND PURPOSE: Intravenous thrombolysis is a well-established treatment for acute ischemic stroke. Our aim was to quantify the effect of each minute delay in door-to-needle time (DNT) on 90-day survival, intracerebral hemorrhagic complication <36 hours, and functional outcomes at 3 months, in routine clinical practice. METHODS: Our nationwide registry-based study included 14 132 adult patient admissions with ischemic stroke receiving intravenous thrombolysis from 2010 to 2017. Outcomes were analyzed using multivariable logistic regression, adjusting for potential confounders. RESULTS: Median DNT was 47 minutes, with an improvement from 65 to 38 minutes during the study. Median age was 74 years, and median National Institutes of Health Stroke Scale 8 points. We found a significant impact of each minute delay in DNT with reduced odds of survival by 0.6%, increased odds of intracerebral hemorrhagic and worse activities of daily living by 0.3%, and worse living conditions and mobility by 0.4%. CONCLUSIONS: Improving DNT is a key factor in achieving good outcomes after stroke. We estimate that in Sweden alone in 2017, compared with 2010, the shorter DNT achieved have saved 38 lives, avoided 8 intracerebral hemorrhagic transformations, and spared, respectively, 36, 51, and 52 patients from a worsening in activities of daily living, living conditions, and mobility. DNT is sensitive for interventions and should be targeted in quality improvement efforts

Time Trends and Monthly Variation in Swedish Acute Stroke Care

Background and Purpose: Studies of monthly variation in acute stroke care have led to conflicting results. Our objective was to study monthly variation and longitudinal trends in quality of care and patient survival following acute stroke. Methods: Our nationwide study included all adult patients (≥18 years) with acute stroke (ischemic or hemorrhagic), admitted to Swedish hospitals from 2011 to 2016, and that were registered in The Swedish Stroke Register (Riksstroke). We studied how month of admission and longitudinal trends affected acute stroke care and survival. We also studied resilience to this variation among hospitals with different levels of specialization. Results: We included 132,744 stroke admissions. The 90-day survival was highest in May and lowest in January (84.1 vs. 81.5%). Thrombolysis rates and door-to-needle time within 30 min increased from 2011 to 2016 (respectively, 7.3 vs. 12.8% and 7.7 vs. 28.7%). Admission to a stroke unit as first destination of hospital care was lowest in January and highest in June (78.3 vs. 80.5%). Stroke unit admission rates decreased in university hospitals from 2011 to 2016 (83.4 vs. 73.9%), while no such trend were observed in less specialized hospitals. All the differences above remained significant (p &lt; 0.05) after adjustment for possible confounding factors. Conclusion: We found that month of admission and longitudinal trends both affect quality of care and survival of stroke patients in Sweden, and that the effects differ between hospital types. The observed variation suggests an opportunity to improve stroke care in Sweden. Future studies ought to focus on identifying the specific factors driving this variation, for subsequent targeting by quality improvement efforts

Male acoustic display in the sand goby – Essential cue in female choice, but unaffected by supplemental feeding

Many teleost fishes use acoustic and visual signalling during courtship. Such displays may convey information about body condition. Here we experimentally altered body condition of sand goby (Pomatoschistus minutus) males to examine effects on acoustic and visual courtship and subsequent spawning decisions. Over two weeks, males fed in excess were fed daily, whereas food-deprived males were fed once a week. Females only spawned with males that produced courtship sound. However, there were no treatment effects on the occurrence of spawning and males fed in excess did not invest more in visual or acoustic courtship than food-deprived males. That said, males fed in excess built more well-covered nests, with more sand piled on top, compared to food-deprived males. Male condition measured as lipid content differed significantly between treatments. However, only males fed in excess differed in lipid content from wild caught males, indicating that in nature, males are of similar condition to males in the low condition treatment group. Apart from the importance of courtship sound, the only male or female behaviour predicting reproductive success was if male displayed in the nest opening. Males often produce courtship sounds together with a visual display in this position. A female dark-eye display did not associate with reproductive success which, together with previous results, suggest a non-ornamental function of this trait. We conclude that male courtship sounds appear to be crucial in female mate choice, but the information content of the courtship sounds and how it relates to male condition remains elusive.Financial support was provided by the Graduate School in Marine Environmental Research at the Gothenburg Centre for Marine Research, Helge Ax:son Johnssons stiftelse, Herbert &amp; Karin Jacobssons stiftelse (to ELB), the Science and Technology Foundation, Portugal, strategic project UID/MAR/04292/2020 (to MCPA) and the Centre for Marine Evolutionary Biology (http://www.cemeb. scien http://ce.gu.se) (to CK and OS). CeMEB was supported by a Linnaeus-grant from the Swedish Research Councils VR and Formas.</p

Increased noise levels cause behavioural and distributional changes in Atlantic cod and saithe in a large public aquarium—A case study

Abstract Investigating the effects of underwater noise on aquatic animals is a research field that is receiving rapidly increasing attention. Despite this, surprisingly few studies have addressed the potential impacts of noise in a marine animal husbandry setting. In this regard, the behaviour of fish in public aquariums can be used as an indicator of well-being, and noise is known to cause behavioural changes. This case study investigates the behaviour of cod (Gadus morhua) and saithe (Pollachius virens) in a large public aquarium when exposed to increased noise levels originating from an aquarium renovation carried out by construction divers. Swimming behaviour, group formation and vertical distribution, along with yawning and scratching frequencies of the fish, were analysed from video recordings made before, during and after the exposure to increased noise levels. The same parameters were also analysed to evaluate potential effects of the presence of divers when not making renovation noise, compared to fish behaviour prior to the renovation. There was a slight change in the depth distribution of both species and a decrease in the number of scratches in cod due to the presence of divers that were not making renovation noise. In the presence of construction noises in the tank, however, both cod and saithe showed a wider array of behavioural changes, including increased swimming speed, changes in depth distribution and increased yawning frequencies. The results from this case study demonstrate that an underwater renovation with increased noise levels impacts fish behaviour and suggests that underwater noise should be considered during the management of aquatic environments, including public aquaria

Diurnal variations in the quality of stroke care in Sweden

Objectives: A recent study of acute stroke patients in England and Wales revealed several patterns of temporal variation in quality of care. We hypothesized that similar patterns would be present in Sweden and aimed to describe these patterns. Additionally, we aimed to investigate whether hospital type conferred resilience against temporal variation. Materials and Methods: We conducted this nationwide registry-based study using data from the Swedish Stroke Register (Riksstroke) including all adult patients registered with acute stroke between 2011 and 2015. Outcomes included process measures and survival. We modeled time of presentation as on/off-hours, shifts, day of week, 4-hour, and 12-hour time blocks. We studied hospital resilience by comparing outcomes across hospital types. Results: A total of 113 862 stroke events in 72 hospitals were included. The process indicators and survival all showed significant temporal variation. Door-to-needle (DTN) time within 30 minutes was less likely during nighttime than daytime (OR 0.50; 95% CI 0.41-0.60). Patients admitted during off-hours had lower odds of direct stroke unit (SU) admission (OR 0.72; 95% CI 0.70-0.75). 30-day survival was lower in nighttime vs daytime presentations (OR 0.90, 95% CI 0.84-0.96). The effects of temporal variation differed significantly between hospital types for DTN time within 30 minutes and direct SU admission where university hospitals were more resilient than specialized non-university hospitals. Conclusions: Our study shows that variation in quality of care and survival is present throughout the whole week. We also found that university hospitals were more resilient to temporal variation than specialized non-university hospitals