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In oceans, the noise generated by human activities has reached phenomenal proportions, with considerable harmful effects on marine life. Measuring this impact to achieve a sustainable balance for highly vulnerable marine ecosystems, such as coral reefs, is a critical environmental policy objective. Here, we demonstrate that anthropogenic noise alters the interactions of a coral reef fish with its environment and how this behavioural response to noise impairs foraging. In situ observations on the Moorea reef revealed that the damselfish Dascyllus emamo reacts to boat passage by moving closer to its coral bommie, considerably reducing the volume of water available to search for prey. Using boat noise playback experiments in microcosms, we studied D. emamo's behaviour and modeled its functional response (FR), which is the relationship between resource use and resource density, when feeding on juvenile shrimps. Similar to field observations, noise reduced D. emamo's spatial occupancy, accompanied by a lower FR, indicating a reduction in predation independent of prey density. Overall, noise-induced behavioural changes are likely to influence predator-prey interaction dynamics and ultimately the fitness of both protagonists. While there is an urgent need to assess the effect of anthropogenic noise on coral reefs, the ecological framework of the FR approach combined with behavioural metrics provides an essential tool for evaluating the cascading effects of noise on nested ecological interactions at the community level., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Artificial light at night (ALAN) is an increasing anthropogenic pollutant, closely associated with human population density, and now well recognized in both terrestrial and aquatic environments. However, we have a relatively poor understanding of the effects of ALAN in the marine realm. Here, we carried out a field experiment in the coral reef lagoon of Moorea, French Polynesia, to investigate the effects of long-term exposure (18-23 months) to chronic light pollution at night on the survival and growth of wild juvenile orange-fin anemonefish, Amphiprion chrysopterus . Long-term exposure to environmentally relevant underwater illuminance (mean: 4.3 lux), reduced survival (mean: 36%) and growth (mean: 44%) of juvenile anemonefish compared to that of juveniles exposed to natural moonlight underwater (mean: 0.03 lux). Our study carried out in an ecologically realistic situation in which the direct effects of artificial lighting on juvenile anemonefish are combined with the indirect consequences of artificial lighting on other species, such as their competitors, predators, and prey, revealed the negative impacts of ALAN on life-history traits. Not only are there immediate impacts of ALAN on mortality, but the decreased growth of surviving individuals may also have considerable fitness consequences later in life. Future studies examining the mechanisms behind these findings are vital to understand how organisms can cope and survive in nature under this globally increasing pollutant.

Artificial light at night (ALAN) is a growing threat to coastal habitats, and is likely to exacerbate the impacts of other stressors. Kelp forests are dominant habitats on temperate reefs but are declining due to ocean warming and overgrazing. We tested the independent and interactive effects of ALAN (dark versus ALAN) and warming (ambient versus warm) on grazing rates and gonad index of the sea urchin Centrostephanus rodgersii. Within these treatments, urchins were fed either 'fresh' kelp or 'treated' kelp. Treated kelp (Ecklonia radiata) was exposed to the same light and temperature combinations as urchins. We assessed photosynthetic yield, carbon and nitrogen content and C : N ratio of treated kelp to help identify potential drivers behind any effects on urchins. Grazing increased with warming and ALAN for urchins fed fresh kelp, and increased with warming for urchins fed treated kelp. Gonad index was higher in ALAN/ambient and dark/warm treatments compared to dark/ambient treatments for urchins fed fresh kelp. Kelp carbon content was higher in ALAN/ambient treatments than ALAN/warm treatments at one time point. This indicates ocean warming and ALAN may increase urchin grazing pressure on rocky reefs, an important finding for management strategies. [ABSTRACT FROM AUTHOR]

Behavioural analysis has been attracting significant attention as a broad indicator of sub-lethal toxicity and has secured a place as an important subdiscipline in ecotoxicology. Among the most notable characteristics of behavioural research, compared to other established approaches in sub-lethal ecotoxicology (e.g. reproductive and developmental bioassays), are the wide range of study designs being used and the diversity of endpoints considered. At the same time, environmental hazard and risk assessment, which underpins regulatory decisions to protect the environment from potentially harmful chemicals, often recommends that ecotoxicological data be produced following accepted and validated test guidelines. These guidelines typically do not address behavioural changes, meaning that these, often sensitive, effects are not represented in hazard and risk assessments. Here, we propose a new tool, the EthoCRED evaluation method, for assessing the relevance and reliability of behavioural ecotoxicity data, which considers the unique requirements and challenges encountered in this field. This method and accompanying reporting recommendations are designed to serve as an extension of the "Criteria for Reporting and Evaluating Ecotoxicity Data (CRED)" project. As such, EthoCRED can both accommodate the wide array of experimental design approaches seen in behavioural ecotoxicology, and could be readily implemented into regulatory frameworks as deemed appropriate by policy makers of different jurisdictions to allow better integration of knowledge gained from behavioural testing into environmental protection. Furthermore, through our reporting recommendations, we aim to improve the reporting of behavioural studies in the peer-reviewed literature, and thereby increase their usefulness to inform chemical regulation., (© 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.)

Sessile marine invertebrates play a vital role as ecosystem engineers and in benthic–pelagic coupling. Most benthic fauna develop through larval stages and the importance of natural light cycles for larval biology and ecology is long-established. Natural light–dark cycles regulate two of the largest ocean-scale processes that are fundamental to larvae's life cycle: the timing of broadcast spawning for successful fertilization and diel vertical migration for foraging and predator avoidance. Given the reliance on light and the ecological role of larvae, surprisingly little is known about the impacts of artificial light at night (ALAN) on the early life history of habitat-forming species. We quantified ALAN impacts on larval performance (survival, growth, development) of two cosmopolitan ecosystem engineers in temperate marine ecosystems, the mussel Mytilus edulis and the barnacle Austrominius modestus. Higher ALAN irradiance reduced survival in both species (57% and 13%, respectively). ALAN effects on development and growth were small overall, and different between species, time-points and parentage. Our results show that ALAN adversely affects larval survival and reiterates the importance of paternal influence on offspring performance. ALAN impacts on the early life stages of ecosystem engineering species have implications not only for population viability but also the ecological communities that these species support. This article is part of the theme issue 'Light pollution in complex ecological systems'. [ABSTRACT FROM AUTHOR]

Despite 22% of the world's coastal regions experiencing some degree of light pollution, and biologically important artificial light at night (ALAN) reaching large portions of the seafloor (greater than 75%) near coastal developments, the impacts of ALAN on temperate and tropical reefs are still relatively unknown. Because many reef species have evolved in response to low-light nocturnal environments, consistent daily, lunar, and seasonal light cycles, and distinct light spectra, these impacts are likely to be profound. Recent studies have found ALAN can decrease reproductive success of fishes, alter predation rates of invertebrates and fishes, and impact the physiology and biochemistry of reef-building corals. In this paper, we integrate knowledge of the role of natural light in temperate and tropical reefs with a synthesis of the current literature on the impacts of ALAN on reef organisms to explore potential changes at the system level in reef communities exposed to ALAN. Specifically, we identify the direct impacts of ALAN on individual organisms and flow on effects for reef communities, and present potential scenarios where ALAN could significantly alter system-level dynamics, possibly even creating novel ecosystems. Lastly, we highlight large knowledge gaps in our understanding of the overall impact of ALAN on reef systems. This article is part of the theme issue 'Light pollution in complex ecological systems'. [ABSTRACT FROM AUTHOR]

In mammalian research, the implementation of the 3Rs is ubiquitous. However, the adaptation of procedures for experimental work on fish seems less extensive in comparison, even though fish model organisms are common in a broad range of research fields already. To strengthen animal welfare in experimental research, we provide an overview of current research results, including studies on the nociception of fishes. Furthermore, we describe the potential of implementing the 3Rs in fish experimental research. In the context of "Reduction", we show alternative research methods to lethal sampling. Considering "Refinement", we point out possibilities to improve fish handling and indicate that adaptations to the individual species ecology are necessary. Under the aspect of "Replacement", we describe the high potential of cell cultures that can be obtained from fish tissue and give an overview of the already extensive use in ecotoxicology and virology. In addition, we illustrate that cell cultures could also be increasingly used for basic research. [ABSTRACT FROM AUTHOR]

Anemonefishes of the genus Amphiprion are emerging as a model organism for marine science, so there is potentially a lot for the research community to gain by optimizing and standardizing housing and husbandry protocols. Here, we conducted a literature review and a questionnaire survey regarding the housing and husbandry of anemonefishes for use in research. The questionnaire survey was completed by 27 laboratories, with a 45% response rate, across 11 different countries in Europe, North America, Asia and Australia. Results from the literature review identified that housing and husbandry protocols varied widely in terms of tank volume, diet composition and lighting type for the housing of broodstock pairs. These results also emphasize the significant impacts that variation in housing and husbandry protocols have on fish. Results from the questionnaire survey confirmed this. We identified multiple opportunities for improvement of protocols, including the potential for exchange of larvae between laboratories to create strains and reduce pressure on natural populations. In conclusion, our research suggests that the anemonefish research community should be discussing the optimization and standardization of housing and husbandry or, minimally, recognizing that housing and husbandry influence a wide range of traits and will influence the results and conclusions drawn from experiments. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) negatively impacts organisms in many ways, from their feeding behaviors to their response and ability to deal with disease. Our knowledge of ALAN is focused on hosts, but we must also consider their parasites, which constitute half of all described animal species. Here, we assessed the impact of light exposure on a model host-parasite system (Poecilia reticulata and the ectoparasitic monogenean Gyrodactylus turnbulli). First, parasite-free fish were exposed to 12:12 h light:dark (control) or 24:0 h light:dark (ALAN) for 21 days followed by experimental infection. Second, naturally acquired G. turnbulli infections were monitored for 28 days during exposure of their hosts to a specified light regime (6:18 h, 12:12 h, or 24:0 h light:dark). Experimentally infected fish exposed to constant light had, on average, a greater maximum parasite burden than controls, but no other measured parasite metrics were impacted. Host feeding behavior was also significantly affected: fish under ALAN fed faster and took more bites than controls, whilst fish exposed to reduced light fed slower. Thus, ALAN can impact parasite burdens, even in the short term, and altering light conditions will impact fish feeding behavior. Such responses could initiate disease outbreaks or perturb food-webs with wider ecological impacts., (© 2024 The Author(s). Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)

Artificial light at night (ALAN) is a growing global problem altering the behavior of organisms and thereby community composition and ecosystem processes. Research has mostly focused on terrestrial ecosystems, but a growing number of studies show that aquatic ecosystems are increasingly affected. Here, we provide a conceptual framework that describes how ALAN can influence aquatic ecosystems through effects on the behavior of ecologically important invertebrates. These organisms provide a range of critical ecological functions, from serving as food for other organisms to nutrient cycling and the translocation of energy and matter within and between ecosystems. In addition, we systematically searched the literature to assess the current state of the field and identify knowledge gaps. The literature search reveals that an increasing number of studies find light pollution to alter the behavior of aquatic invertebrates, such as their movements, habitat choice, and foraging behavior, but that the fitness consequences of these behavioral changes are largely unknown, as are their impacts on populations, communities, and ecosystems. Yet, assessing the consequences of behavioral changes for higher ecological levels is of vital importance given the central role of these invertebrates in ecosystems. Thus, more research needs to be directed to the ecological consequences of behavioral responses of aquatic invertebrates to light pollution. Overall, more effort should be made to assess the ecological consequences of behavioral responses to ALAN, and, importantly, how negative effects of light pollution could be mitigated. Significance statement: Light pollution is of growing ecological concern and influencing ecosystems through effects on the behavior of organisms. Aquatic ecosystems are increasingly exposed and an ecologically important group of organisms in these systems are invertebrates. Here, we discuss how artificial light at night alters the behavior of aquatic invertebrates and how this in turn influences ecosystem structure and function. Such an understanding of the mechanisms and pathways that underlie the effect of light pollution on aquatic ecosystems is needed if we are to develop efficient strategies to reduce negative effects of human-made lighting systems on ecosystems. [ABSTRACT FROM AUTHOR]

Chub mackerel, Scomber japonicus, is heavily farmed and harvested due to its demand as a high-quality protein source rich in fatty acids. However, the effects of environmental cues on sexual maturation of the fish remain understudied. We aim to elucidate the effect of light manipulation on the hormones related to reproduction and on the stress response in the species. Mackerel were exposed to different photoperiods (12 h light:12 h dark or 14 h light:10 h dark) and light wavelengths (provided by white fluorescent bulbs or green LEDs). Total RNA extracted from the brain was assayed with quantitative polymerase chain reaction (a powerful technique for advancing functional genomics) and blood plasma was analyzed via immunoassay using ELISA kits. The mRNA expression of gene-encoding gonadotropin-releasing hormone, gonadotropin hormone, follicle-stimulating hormone, and luteinizing hormone were significantly increased through the use of an extended photoperiod and green wavelength, which also increased testosterone and 17β-estradiol plasma levels. Plasma levels of cortisol and glucose, which are indicators of a stress response, were significantly decreased through green LED exposure. Our results indicate that environmental light conditions affect the production of pituitary and sex hormones, and reduce the stress response in S. japonicus. [ABSTRACT FROM AUTHOR]

Phenotypic adjustments to environmental variation are particularly relevant to cope with putative environmental mismatches often imposed by natal dispersal.We used an intergenerational cross‐transplant field‐based experiment to evaluate the morphological and physiological effects of parental and postsettlement water flow environments on the orange‐fin anemonefish Amphiprion chrysopterus through ontogeny (at pre‐ and postsettlement stages).Offspring born from parents under high water flow had an 18% higher caudal fin aspect ratio (a compound measure of shape) at the presettlement stage, 10% slower growth after settlement, and 55% lower survival after settlement compared to offspring from low water flow parents. At the presettlement stage, caudal fin length was determined by parental caudal fin length. At the postsettlement stage, fish survived equally well with similar phenotypes in both high and low developmental flow environments. However, results suggest potential developmental phenotypic plasticity in caudal fin length, which increases more under low water flow during development. After settlement, growth was the only morphological or physiological trait that was associated with parental water flow, which was lower from parents under high flow, as was survival.These results give important insights into the parental contribution, both genetic and nongenetic, in determining early offspring phenotype and subsequent growth and survival. Our results also suggest that offspring may possess flexibility to cope with a wide range of local environments including those different from their parents. Overall, the findings of this study show the fitness consequences of living in different environments and the likely trade‐offs between parental and offspring fitness in a wild population. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The nighttime is undergoing unprecedented change across much of the world, with natural light cycles altered by the introduction of artificial light emissions. Here we review the extent and dynamics of artificial light at night (ALAN), the benefits that ALAN provides, the environmental costs ALAN creates, approaches to mitigating these negative effects, and how costs are likely to change in the future. We particularly highlight the consequences of the increasingly widespread use of light-emitting diode (LED) technology for new lighting installations and to retrofit pre-existing ones. Although this has been characterized as a technological lighting revolution, it also constitutes a revolution in the environmental costs and impacts of ALAN, particularly because the LEDs commonly used for outdoor lighting have significant emissions at the blue wavelengths to which many biological responses are particularly sensitive. It is clear that a very different approach to the use of artificial lighting is required. [ABSTRACT FROM AUTHOR]

Humans first began using artificial light at night (ALAN) during the industrial revolution and sources of light have diversified and intensified considerably over the last century. Light pollution has previously been defined under two separate branches, “ecological light pollution” where the natural light patterns are altered in marine and terrestrial environments, and “astronomical light pollution” where the view of the night sky is reduced. Natural light is vital for the regulation of animal behaviour and interactions. Surprisingly, this environmental stressor did not become a worldwide concern until 2009. Since then, research into this subject has substantially increased, with studies highlighting the detrimental effects of ALAN. These effects can be serious for many organisms and include the disruption of the essential circadian rhythms that most organisms use to time important behaviours such as foraging, reproduction, and sleep. Whether all organisms possess phenotypic plasticity to effectively adapt to increasing and changing artificial light pollution is not yet known. Here, we summarise the effects of light pollution among many different species, from marine to terrestrial, with a focus on the areas that require further research to enhance our knowledge of this subject. The aim of this review is to raise awareness and enhance understanding about this little-discussed environmental concern, including some novel ideas on camouflage and polarised light pollution, hopefully encouraging future research into the effects of light pollution on organism behaviour. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) is an increasing anthropogenic pollutant, closely associated with human population density, and now well recognized in both terrestrial and aquatic environments. However, we have a relatively poor understanding of the effects of ALAN in the marine realm. Here,we carried out a field experiment in the coral reef lagoon of Moorea, French Polynesia, to investigate the effects of long-term exposure (18–23 months) to chronic light pollution at night on the survival and growth of wild juvenile orange-fin anemonefish, Amphiprion chrysopterus. Long-term exposure to environmentally relevant underwater illuminance (mean: 4.3 lux), reduced survival (mean: 36%) and growth (mean: 44%) of juvenile anemonefish compared to that of juveniles exposed to natural moonlight underwater (mean: 0.03 lux). Our study carried out in an ecologically realistic situation in which the direct effects of artificial lighting on juvenile anemonefish are combined with the indirect consequences of artificial lighting on other species, such as their competitors, predators, and prey, revealed the negative impacts of ALAN on life-history traits. Not only are there immediate impacts of ALAN on mortality, but the decreased growth of surviving individuals may also have considerable fitness consequences later in life. Future studies examining the mechanisms behind these findings are vital to understand how organisms can cope and survive in nature under this globally increasing pollutant. [ABSTRACT FROM AUTHOR]