Joao Luis Saraiva

• PhD
• Group Leader at Centro de Ciências do Mar

This study explores electrical stunning, anaesthesia, and no stunning, followed by slaughter using either ice-slurry or the ikejime technique in gilthead seabream (Sparus aurata). Fish were monitored for visual signs of consciousness, heart rate, internal temperature, plasma stress and osmotic parameters, and muscle quality parameters.

In interspecific signalling, vivid colours have been interpreted to enable species recognition and maximise signal detection. Recently, it has been shown that vivid colours can also convey information on individual fitness which could be advantageous for receivers. In the marine cleaning mutualism between the Indo-Pacific Bluestreak cleaner wrasse...

Neuropeptides are highly variable but widely conserved molecules, the main functions of which are the regulation and coordination of physiological processes and behaviors. They are synthesized in the nervous system and generally act on other neuronal and non‐neuronal tissues or organs. In recent years, diverse neuropeptide isoforms and their recept...

Changes in water quality significantly shape fish behavior, a crucial index reflecting the growth and welfare status of fish. Given the centrality of this relationship to aquaculture practices, a comprehensive understanding of how water quality dynamics influence fish behavior is imperative. While there have been some summaries of the effects of wa...

An adequate understanding of fish behaviors and their interaction with farm-specific environments is pivotal for enhancing fish welfare in aquaculture. The fair-fish database aims to provide a consistent overview of the welfare of farmed fish. This platform consolidates ethological knowledge into profiles of farmed aquatic species. Its WelfareCheck...

Wild-capture fisheries are important for global food security, particularly in developing nations; • Aquatic animal welfare is increasingly becoming a topic on the agenda of governments; • European consumers believe fish deserve the same protection as other production animals; • Growing evidence that poor catch welfare impacts both the sustainabili...

Fish welfare is a critical issue that needs to be addressed by the rapidly growing aquaculture industry. Scientific knowledge regarding the natural behaviors of species and the conditions in which they are kept in farms is essential for improving their welfare in aquaculture. To provide a consistent overview of the welfare of farmed fish, the organ...

The intensification of aquaculture practices in the last decade can compromise the welfare of farmed fish. However, one strategy to be considered to improve the welfare of captive fish is the implementation of structural enrichment in the rearing environment. The behavioural and physiological effects of suspended ropes inside rearing tanks were exp...

A critical point in the life of a captive fish is the final stages of production, not only in welfare terms but also due to effects on meat quality, carcass appearance and derived economic impacts. The most common method to slaughter fish is by asphyxia either in ice-water or in the open air. In humane slaughter procedures, however, a stunning meth...

Several studies have reported the neurophysiological and behavioural mechanisms that enable fish to experience several types of affective states, such as fear, pain and joy. This is crucial for the welfare feelings‐based approach, as conditions that bring positive or negative valence to fish influence their affective state. A method to understand t...

https://fair-fish-database.net/db/species/litopenaeus-vannamei/farm/welfarecheck/

Fishes in aquaculture face several potential challenges that may affect their welfare. These challenges may be ethological (spatial, social, reproductive, feeding), physiological (homeostasis and health issues including disease and parasites), environmental (water quality and characteristics, light, complexity), and human-induced (operations and ro...

The effects of stocking density on fish welfare are complex and involve many interacting parameters. This complex relationship between fish welfare, stocking density and influencing factors make it challenging to define a specific optimal (“golden”) stocking density. Indeed, previously published recommendations on stocking density for different spe...

The summer shoal is back in 2022! After a forced halt in the last two years, 2022 marks the return of the pioneer event gathering stakeholders in constructive dialogue around the welfare of fish. The Fishethogroup, fair-fish international and CCMAR are pleased to announce the IV Summer Shoal in Fish Ethology and Welfare 2022. In recent times, the...

Structural enrichment is considered a useful tool to improve the welfare conditions of captive fish by deliberately increasing the physical heterogeneity and complexity of captivity environments. However, the potential effects of structural enrichment on the stress response at the group level and on social interactions have not been well studied ye...

Environmental enrichment can improve the welfare of captive fish. Its objective is to provide new sensorial and motor stimulation in order to help meet their behavioural, physiological, morphological and psychological needs, while reducing stress and frequency of abnormal behaviours. In fish farms, rearing environments are usually designed from a h...

Welfare in aquaculture is a pressing topic. One of the main measures to improve the life of farmed fish is implementing environmental enrichment, which can include the addition of structural covers to rearing tanks. Here we test the effects of tank covers (fully covered, 50% covered and uncovered) in an all-male population (N=75 tagged individuals:...

The purpose of this study is to analyse the particular welfare needs in live animal transport of aquatic animals. The in-depth analysis describes the key causes of suffering in relation to the needs of farmed fish, and explores strengths and weaknesses in the EU regulation and in current guidelines. Recommendations are made to mitigate the many wel...

Structural enrichment in tanks enhances spatial cognition of Gilthead seabream

Using acoustic telemetry to monitor swimming behaviour of seabream in sea-cages

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Fish welfare in aquaculture – problems and approaches to solutions. Free download: http://www.ign-nutztierhaltung.ch/sites/default/files/Bilder/IGN_FOKUS20_Broschuere_Fischwohl_100Seiter_web.pdf (The English edition will be available in late spring 2021.)

Acoustic telemetry techniques are very useful tools to monitor in detail the swimming behavior and spatial use of fish in artificial rearing environments at individual and group levels. We evaluated the feasibility of using passive acoustic telemetry to monitor fish welfare in sea-cage aquaculture at an industrial scale, characterizing for the firs...

Environmental enrichment is considered as a recommended tool to guarantee or improve the welfare of captive fish. This study demonstrates for the first time that structural environmental enrichment enhances cognition, exploratory behaviour and brain physiological functions of gilthead seabream (Sparus aurata). Seabream was reared in groups (n = 15)...

The legal protection of a ‘farmed’ fish in Europe – analysing the range of EU legislation and the impact of international animal welfare standards for the fishes in European aquaculture ABSTRACT Nowadays, fishes are one of the most exploited ‘farm’ animals. They are reared in marine and freshwater aquaculture farms, which represent one of the fas...

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It is true that happiness is a subjective evaluation of an internal state, so the word may be misleading when referring to animals. It is also true that positive emotional states have been receiving far less attention than negative, perhaps for obvious reasons. Here I briefly review some of the evidence for happiness in fishes.

Invasive species are recognized as a major cause of biodiversity decline. Legal regulations relating to the prevention, control, or eradication of invasive species should always be up-to-date, as the failure to recognize the problem, lack of adequate scientific information, or long legal intervals required to prepare the legislation may result in i...

Welfare is a complex, multidimensional concept that can be broadly described as the state of an animal as it copes with the environment. Rearing conditions of finfish aquaculture and experimentation can impair welfare of captive fishes through stress, negative emotional states, health problems, and even mortality. Chemical, physical, social and ot...

Current production systems of finfish aquaculture, and in particular intensive farming systems, can cause welfare problems leading not only to poor condition of the fish but also to a decrease in product quality. Adding structural environmental enrichment (EE) to bare rearing environments may improve the welfare of certain cultured fish. In this st...

The concept of fish welfare is fairly recent and was overlooked for many years, based on a popular misconception that fish were “stupid” creatures devoid of any kind of sentience or mental capability [...]

Structural environmental enrichment (EE), that is, a deliberate addition of physical complexity to the rearing environment, is recently considered as a highly recommended tool to guarantee or improve the welfare of laboratory or captive fish. Structural EE allows the animals a greater control over their environment and experiencing new situations,...

Fish welfare is an essential issue that needs to be tackled by the aquaculture industry. In order to address it, studies have been limited to a small number of species and the information is generally scattered. In order to have a consistent overview of the welfare of farmed fishes, we present the FishEthoBase, an open-access database that ultimate...

ISBN: 978-84-09-11292-0

ISBN: 978-84-09-11292-0

Many certification schemes appeared in recent years for environmental friendly, safe, ethical, and sustainable food production. Presently, there are at least 30 certification schemes relevant to aquaculture production, including schemes promoted by retailers, industry, governments, NGOs and other organizations. However, none of them include specifi...

The domestication of fish species is still in its early stages when compared to terrestrial animals. The effects of domestication on welfare of farmed fishes are complex to study because fish differ from livestock in genetics, physiology and behaviour, and experience different sensory worlds. Consequently, empathy with fish and understanding of the...

A non-native cichlid fish firstly reported in Portugal in 1940 was originally identified as Cichlasoma facetum (Jenyns 1842) based on specimens reported from “Praia de Mira” (Vouga drainage, northwestern Portugal). Currently, the species is known only from three southern Portuguese river drainages, namely Sado, Arade and Guadiana, and no other reco...

Fish farming is a growing industry worldwide. While ecologically sustainable directives and practices have been introduced in recent years, fish welfare has been overlooked. Here we present FishEthoBase, an open-access database assessing current and prospective welfare of farmed fish. For each species, we propose 10 critical questions covering ecol...

Androgens, namely 11­ketotestosterone (11KT), have a central role in male fish reproductive physiology and are thought to be involved in both aggression and social signalling. Aggressive encounters occur frequently in social species, and fights may cause energy depletion, injury and loss of social status. Signalling for social dominance and fightin...

Australoheros facetus is a neotropical cichlid and an exotic species in the Guadiana and Odelouca basins (Southern Portugal). In this research, we aimed to characterize the main behavioural patterns and circulating hormones, 17β-estradiol (E2) for females, and testosterone, 11-ketotestosterone (11KT) and cortisol for both sexes during the formation...

FishEthoBase short profiles focus on 10 core ethological criteria, scoring the findings in a risk analysis along 3 dimensions: Likelihood of fish welfare under minimal farming conditions, Potential of improving fish welfare, and Certainty of the findings. The sum of high values in the 3 dimensions yields the FishEthoScore, a sharp assessment of the...

The present study shows that the olfactory potency of intestinal and bile fluids taken from dominant male chameleon cichlids Australoheros facetus is greater than those from subordinate males. Thus, dominant status may be communicated by odorants released in the intestinal fluid and bile acids may contribute towards this.

Invasive fish may expand their geographical distribution through thermal tolerance mechanisms that allow them to endure severe temperature variations. In this work we provide critical thermal maximum (CTMax) and minimum (CTMin) for Australoheros facetus, a neotropical cichlid found in Southern Portugal, and assess physiological mechanisms of therma...

Males often use scent to communicate their dominance, and to mediate aggressive and breeding behaviors. In teleost fish, however, the chemical composition of male pheromones is poorly understood. Male Mozambique tilapia, Oreochromis mossambicus, use urine that signals social status and primes females to spawn. The urinary sex pheromone directed at...

Australoheros facetus is a highly social neotropical cichlid that is invasive in the Guadiana and Odelouca basins (Southern Portugal). Phenotypic plasticity is believed to be a key component for invasive success. However, its biology remains largely unknown. In this research we aimed to characterize the behaviour and hormone profiles (Testosterone...

In species with plastic expression of alternative reproductive tactics (ARTs), individuals of the same sex, usually males, can adopt different reproductive tactics depending on factors such as body size. The “birthdate hypothesis” proposes that condition dependent expression of ARTs may ultimately depend on birthdate, because individuals born at d...

Chemical communication is widespread in the animal kingdom and olfaction constitutes a powerful channel for social and environmental cues. In fish, olfactory stimuli are known to influence physiological processes, including reproduction. Here we investigate the effects of olfaction on puberty in European sea bass Dicentrarchus labrax males. Intact...

Background The vertebrate brain plays a critical role in the regulation of sexual maturation and reproduction by integrating environmental information with developmental and endocrine status. The European eel Anguilla anguilla is an important species in which to better understand the neuroendocrine factors that control reproduction because it is an...

Teleost eggs contain an abundant store of maternal thyroid hormones (THs) and early in zebrafish embryonic development all the genes necessary for TH signalling are expressed. Nonetheless the function of THs in embryonic development remains elusive. To test the hypothesis that THs are fundamental for zebrafish embryonic development an MCT8 knockdow...

The ‘challenge hypothesis’ suggests that animals facing a social challenge mount an endocrine response that usually results in an increase in androgens when they succeed, and a decrease when they do not. A reported exception appears to be when Mozambique tilapia Oreochromis mossambicus males mount escalating fights against their own mirror image, b...

Chemical communication is a widespread phenomenon in the animal world but, in teleosts, very few pheromones have been chemically identified. In this work we present a bioassay to test synthetic analogues of a putative dominance pheromone in the Mozambique tilapia Oreochromis mossambicus. Social groups of five females and five males were observed to...

The inter-populational variation in the reproductive behaviour of the peacock blenny Salaria pavo (Risso 1810), particularly the influence of the ecologic environment, was reviewed in the present work. Two populations of this species inhabiting contrasting environments were studied: the Ria Formosa population, a coastal lagoon with sandy/muddy subs...

Introduction: The inter-populational variation in the reproductive behaviour of the peacock blenny Salaria pavo, particularly the influence of the ecologic environment, was investigated in the present work. Two populations of this species inhabiting contrasting environments were studied: the Ria Formosa population, a coastal lagoon with sandy/muddy...

The ecology and mating system of two populations of the peacock blenny Salaria pavo that have been reported to differ in sexual behaviour were studied. In the Gulf of Trieste, a northern Adriatic Sea population lives in rocky shores, whilst in the Ria Formosa, an Atlantic population inhabits a coastal lagoon with sandy barrier islands. In the Gulf...

In the peacock blenny (Salaria pavo) the reproductive behaviour is described to vary between two populations that differ in nest availability. At the Gulf of Trieste (GT), Italy, where nest availability is high, conventional sex roles are present and males adopting an alternative par-asitic reproductive tactic are rare. Conversely, at Ria Formosa (...

Morphology and endocrinology were studied in two populations of the peacock blenny Salaria pavo, with different regimes of sexual selection imposed by differences in nest site availability. The peacock blenny is a small, sexually dimorphic benthic fish that presents exclusive paternal care of the clutch and inhabits rocky shores of the Mediterranea...

Aromatase, the key enzyme in the conversion of androgens to estrogens, regulates the availability of these hormones in tissues and controls many physiological and behavioral processes. In fish and other vertebrates, the regulation of aromatase expression in the brain has been implicated in the modulation of male sexual and aggressive behaviors. Her...