JZAR Evidence-based practice Evidence-based practice Goal-oriented behavioural and environmental enrichment in aquarium species Tania Monreal-Pawlowsky1, Ruta Vaicekauskaitė2, Gemma Palencia Membrive3, Fabienne Delfour4 and Xavier Manteca5 1 International Zoo Veterinary Group, Station House, Parkwood Street, Keighley, West Yorkshire, BD21 4NQ, United Kingdom 2 Fox Consulting, 8 rue de l’Aqueduc, 67500 Haguenau, France 3 Parc Zoològic de Barcelona, 08003 Barcelona, Spain 4 Ecole Pratique des Hautes Etudes, 47 rue des Ecoles, 75005 Paris, France 5 Zoo Animal Welfare Education Centre (ZAWEC), School of Veterinary Science, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain Correspondence: Tania Monreal-Pawlowsky, email; T.monreal@izvg.co.uk Keywords: animal welfare; aquatic Abstract species; behavioural diversity; Environmental enrichment is a common tool used in zoo and aquarium settings to provide mental and behavioural needs; environmental physical stimulation to animals under human care. This paper aims to present a primary approach to enrichment; species-specific behaviours goal-oriented environmental and behavioural enrichment following a simplified version of the SPIDER method for a diverse range of aquarium-housed species. The aim of the proposed goal-oriented Article history: environmental-enrichment programme is to stimulate behavioural diversity by providing controlled Received: 03 Dec 2020 stimuli. This programme is easy to implement and can be used by animal care staff; it encompasses an Accepted: 09 Aug 2021 easy evaluation form for daily monitoring and seeks to increase species-specific behavioural diversity. OPEN ACCESS Published online: 31 Oct 2021 It is suggested that environmental enrichment programmes should be designed for the benefit of animal welfare; understanding how they affect animals under human care is essential to take informed decisions about which behaviours or situations to stimulate. An environmental enrichment protocol was developed which considers the ethology and biology of the species under consideration prior to implementation. Specific goals (i.e., behaviours and/or actions) were assigned to particular stimuli (enrichment devices) and the efficacy of the enrichment devices were assessed by reporting on the reactions of the animals. Over time, this protocol has made it possible to define a validated catalogue of enrichment devices for which specific goals and expected reactions are consistent. The increased behavioural diversity achieved with this programme is providing aquatic species with the choice to display species-specific behaviours. Background nevertheless, much ambiguity with respect to the consistency of these effects. For these reasons, it is important to continue International legislation and guidelines for fish under to investigate the effects of environmental enrichment on professional care are becoming increasingly detailed and aquatic species. do often recognise that environmental enrichment may be The original definition of environmental enrichment by required to guarantee good welfare (Batt et al. 2005; Johansen Shepherdson (1998) stated that enrichment is “an animal et al. 2005; Council of Europe 2006; Näslund and Johnsson husbandry principle that seeks to enhance the quality of captive 2016). animal care by identifying and providing the environmental Many studies suggest that environmental enrichment can stimuli necessary for optimal psychological and physiological affect, for example, behaviour, growth performance, survival well-being”. and physiology of fish and aquatic invertebrates under human Hughes and Duncan (1988) suggested that animals under care (Smith 2006; Huntingford et al. 2007; 2012; Goosen human care have behavioural needs, and these are essential et al. 2008; Kato et al. 2010; Costa et al. 2011). There is, for the welfare of these animals (Young 2003). Goldblatt (1993) Journal of Zoo and Aquarium Research 9(4) 2021 273 https://doi.org/10.19227/jzar.v9i4.588 Monreal-Pawlowsky et al. further suggested that behavioural engineering, linked with the handle and cope with it. Additionally, considering the ethogram- performance of species-specific behaviours, may help to increase based approach, it is important that environmental enrichment is the complexity of environments in which animals are held under goal oriented (Shepherdson et al. 1989; Dawkins 1990; Newberry human care and to provide them with some control over it. Allard 1995; The Shape of Enrichment ®; SPIDER; Mellen and MacPhee and Bashaw (2019) discussed the importance of giving animals 2001; Young 2003; Alligood and Leighty 2015; Näslund and choice and control over certain aspects of their environment to Johnsson 2016). promote good welfare. This paper presents a case study of environmental enrichment It is widely accepted that good welfare includes not only the based on stimulating species-specific behaviours frequently absence of negative affective states but also the presence of observed in nature. More specifically, the main aim was to facilitate positive ones and hence there is a need to identify and validate the expression of behavioural needs; that is, those behaviours positive welfare indicators (Miller et al. 2020). While the concept that the performance of rewards in itself and that are controlled of behavioural diversity has not been validated as a positive mainly by intrinsic factors (Hughes and Duncan 1988). Particular indicator of welfare, the review of Miller and colleagues suggests actions were assigned to each enrichment, and the reactions of that it could be an important positive indicator for assessing the animals were rated. To the authors’ knowledge, this is the first welfare. Behavioural diversity is often found to be higher following time a detailed environmental enrichment programme has been animal management practices, such as providing environmental presented for aquatic species in such context. enrichment or an increased habitat complexity. Most studies have examined the impact of enrichment on behavioural diversity, as Action this was one of the original goals of enrichment programmes (Young 2003); however, there are very few studies on aquatic The development of the six-staged environmental enrichment species. protocol began in 2014 and has since been implemented in over 10 An important consideration when developing the enrichment facilities, both in aquarium and zoological park settings. Aquarists programme was that species-specific behaviours observed in the and zookeepers were provided with a two-day enrichment wild are commonly used as the basis for good animal welfare. course, during which the basics of environmental and behavioural Browning (2019) noted that behaviours observed in the wild are enrichment were discussed, and ethogram availability of the not necessarily a good welfare indicator for animals under human species housed was sought and developed. With this information care. She stated that some natural behaviours may decrease and detail on observations regarding behavioural needs of the welfare, while some behaviours not seen in nature may increase animals housed, a table was created to start the enrichment it. programme (Table 1). In this table, the action and the expected It is long accepted that animals kept in aquarium settings need reaction were detailed to prevent interobserver variability as environmental enrichment to ensure their welfare (Bull 2002; much as possible. Smith et al. 2004; 2006; Kihslinger and Nevitt 2006; Näslund The range of species to which this programme has been and Johnsson 2016; Arechavala-Lopez et al. 2019). For example, applied is large and diverse, ranging from bottlenose dolphins undesirable behaviours, such as escape jetting (cephalopods (Tursiops truncatus) and pinnipeds (Zalophus californianus, Otaria achieving a high speed through the use of jetting propulsion, flavescens and Phoca vitulina) to penguins (Pygoscelis papua and which in limited-size environments can become dangerous for the Spheniscus humboldti), sea turtles (Caretta caretta and Chelonia animal) and autophagy (consumption of the body’s own tissues), mydas), poison dart frogs (Dendrobates spp.), several species of can be decreased seemingly as a result of the use of enrichment sharks (Carcharhinus melanopterus, Ginglymostoma cirratum, (Beigel and Boal 2006). In addition, enrichment can increase Hemiscyllium ocellatum, Chiloscyllium punctatum, Stegostoma the overall activity level of the animal, participating for a better fasciatum), crustaceans (Homarus gammarus, Odontodactylus display (Reihling 2001); providing variety in looking for and finding scyllarus), octopus (Octopus vulgaris, Enteroctopus dofleini) and food could also lead to better welfare of the animals (Näslund teleosts (Epinephelus marginatus, Salmo trutta, Pygocentrus and Johnsson 2016). A study by Kuba et al. (2010) showed that nattereri, etc.). These species are commonly found in zoological cartilaginous fish can be used to study the origin and evolution parks and aquaria but enrichment programmes are not commonly of cognitive traits using a tube test apparatus (environmental developed for fish and invertebrates; therefore, this paper enrichment) and the water as an agent to extract food from the focussed mostly on these species. device. The aim was to develop the enrichment programme for long- Environmental enrichment devices are often artificial by nature term use, comprising monthly reviews and readjustment(s). as they are assembled using human-made materials. At the same The programme encompasses behavioural goals to be achieved time, such objects can be perceived as natural because they are through chosen enrichment devices which are then implemented, intended to stimulate species-specific natural behaviours (Young evaluated and assessed. The protocol can be summarised as et al. 1994; Kreger et al. 1998; Young 2003). follows: The idea of developing an environmental enrichment programme based on an ethogram arose from Fraser’s consideration of animal 1. Species-specific behaviours and experimental ethogram in welfare (Fraser 2008). By describing different concerns about each facility animal welfare, he introduced three criteria: ‘basic health and functioning’, ‘affective states’ and ‘natural living’. In the natural The method is based on researching the general ethogram of the living section, Fraser emphasised that individual animals should target species, as well as the particular behavioural repertoire be able “to lead reasonable natural lives by carrying out natural expressed within the group or individual under consideration. behaviours”. Animals kept under human care should be allowed to express these species-specific behaviours, and environmental 2. Goals to be reached or behaviours to be stimulated enrichment programmes are a tool to aid in achieving this overarching goal. The general species ethogram and the specific behavioural Environmental enrichment can encourage behaviours that do repertoire defined during Phase 1 are then compared to identify not necessarily influence welfare in a positive way. Animals can species-specific behaviours that positively influence welfare but be exposed to frustration through enrichment, provided they can are not displayed by certain individual animals. These behaviours 274 Journal of Zoo and Aquarium Research 9(4) 2021 https://doi.org/10.19227/jzar.v9i4.588 Goal-oriented environmental enrichment in aquarium species are then targeted by the enrichment programme through specific implementation, the animal keepers/aquarists have to record the enrichment devices to facilitate the animal or group of animals to reactions of the animals to the enrichment device provided (Table display their behavioural diversity spectrum. At this stage, and in 1). the general context of welfare of animals under human care, the Reactions of the animals are to be recorded by the animal global idea is to promote and/or encourage the display of species- staff, classified into six possible outcomes or reactions towards specific behaviours within a group of animals or an individual. the enrichment devices, A to F (Figure 2). This scale extends from the ‘expected reaction’ (A) being observed throughout the whole 3. Defining a detailed enrichment programme dedicated timeslot defined in advance, to a ‘negative’ reaction (F), for example, aggression or fear. The outcome categories also The enrichment devices are categorised into the five enrichment include ‘not expected’ reactions or ‘no reaction’. To facilitate the types described in The Shape of Enrichment ®: cognitive, social, application of this method as part of the daily management of the sensory, structural and nutritional. animals, categories were colour coded (Figure 2). It is important that enrichment devices are used randomly The reaction categories enable an evaluation of the efficacy and not always at the same time of the day to prevent them of the enrichment device. The evaluation sheet therefore from becoming routine for the animals. In detailing the action to encompasses all the information required to assess efficacy: be taken, the animal care team need to set the device use time date, keeper’s name, enrichment device used, enrichment type, based on the expected reaction from that particular species and detailed description of the actions to be taken, goal of enrichment, its biology. Nocturnal species will not react to enrichment devices description of the expected reaction, description of the observed provided in the middle of the day and on the contrary, enrichment reaction and a final evaluation of the enrichment device. provided at night will be of little use to species active during the day. 5. Analysis and readjustment(s) This monitored enrichment programme was also designed to prevent animals from being trained to react the expected way, as A general review of the programme is performed on a monthly the goal of the programme is to stimulate certain behaviours and basis to identify the real impact of the enrichment devices and to give the animals the choice of interacting or engaging with the to evaluate the need for improvement and/or readjusting. If an environmental device, hence giving them control in that particular expected behaviour is not obtained in a consistent manner for moment (Allard and Bashaw 2019). Therefore, specific rules are several individual animals, the programme has failed to stimulate given and are to be followed throughout the programme (Figure the desired behaviour and the specific environmental device 1). needs to be re-assessed. The systematic records taken of animal reactions has enabled 4. Observation and reporting of the reactions of the animals the strengthening of the model over the years and a consolidation of the links between each intended goal and each enrichment A protocol to assess the results and the consequences of each device used, as well as the expected behaviours or reactions to chosen enrichment device was created. During enrichment each of these devices. No. Rule 1. Behaviours should not be reinforced by the keepers. 2. Choice should be given to an animal whether or not to interact with the provided enrichment device. This will help understanding if the goal/s is/are achieved. Code Colour Reaction 3. The animal should not be asked to bring back enrichment F10 Negative: animal attacks the object and/or hides device/s. away and/or shows distress. 4. Professional care staff should not interact with the animal E8 No reaction: animal does not show any kind of during environmental enrichment sessions unless specified reaction to the enrichment device. in the actions to be taken. D5 Not the expected reaction: animal does something 5. Preparation of the enrichment devices, especially different than the goal. It is not necessarily bad since nutritional ones, should not be visible for the animal. we might have stimulated a different behaviour than 6. Time of the day for environmental enrichment sessions that originally intended. should be chosen randomly and based on the biology of the C3 Expected reaction at first but then turns negative. species. B2 Expected reaction but not for the planned time. 7. Environmental enrichment sessions should be evaluated by professional care staff. A1 Expected reaction. Figure 1. Simplified rules to follow while implementing the species-specific Figure 2. Six possible outcomes or possible reactions of the animals goal-oriented enrichment programme. towards the enrichment devices used. Journal of Zoo and Aquarium Research 9(4) 2021 275 https://doi.org/10.19227/jzar.v9i4.588 276 Table 1. Action, goal and expected reactions to enrichment. Date, time, Species ED Action Enrichment Goal Expected reaction Obtained reaction Comments Evaluation who type 21 Jan Spiny lobster Feeding Three feeding rings are prepared with Nutritional Increase the time The spiny lobsters should seek The lobster (and fish) Rest of A1 2019, Panilurus elephas rings anchovies and saithe inside; do not they spend looking for and find the food in the rings were interesed in the animals 1430, CZ exceed 50% of their daily diet. Place food/obtaining food. on the floor of the aquarium, devices and spent the in the the rings at the bottom of the tank. Give choice over what choose what they want to eat planned time getting tank were These rings are to be left in the tank for they want to eat. and spend at least 15 mins food out. No aggression interesed maximum 15 mins. trying to get the food out of occurred. too. the rings. 22 Jan Green sea turtle Brush Two brushes are held by one aquarist Sensory Provide the animals The turtles will come to the The turtles approach They want B2 2019, Chelonia mydas x 2 on the water surface to allow the sea with the opportunity surface and rub their carapace the brushes and used more than 1300, CZ turtles to scratch their back (10-15 of scratching off algae actively against the brushes them in less than 5 mins, 15 mins! mins); do not follow the animal with and dead dermal cells within 5 mins of them being almost immediately. the brush. Remain static and only brush from their carapace, introduced. They might try to They didn’t bite them. if the animal approaches. If they bite as they would do in bite them. the brushes, remove them from the the wild with rocks pool and place them back in a few seconds later. 23 Jan Common octopus Matryoshka Provide a variety of foods, depending Nutritional, Increase foraging Octopus should approach the ED was taken and The difficulty A1 2019, Octopus vulgaris doll on availability, inside the Matryoshka structural, time and exploratory ED in less than a minute and opened in less time than of the ED 1130, CZ doll; do not exceed 15% of the daily sensory and behaviour, stimulate find out how to open the doll expected. could be diet. Place the doll inside the tank and cognitive cognitive abilities and eat the food in less than 10 increased. let it sink to the bottom on its own (15 mins. Expected reaction would Maybe by mins). be for it to catch it in mid water adding three and not let it float down to the dolls? Monreal-Pawlowsky et al. bottom. 24 Jan Rays Raja spp. and Feeding Three 60 cm long performated Nutritional Increase foraging time The rays should approach the ED was accepted and At times A1 2019, large fresh water pipes PVC pipes, 75 mm in diameter, are and sensory and olfactory sense, feeding pipes in less than 2 the rays got the food there was 1000, DA species displays provided. Pipes are filled with a variety stimulate exploratory mins and start rolling on them out together, same with strong of food; do not exceed 50% of the dail behaviours and to get the food out. In the case the fish. competition; diet. They are placed on the bottom of cognitive abilities by of fish, larger specimens should all animals the tank, as far apart as possible, and getting them to find push the pipes so that food falls tried to get left for 15 mins. out how to get the through the holes and can be food from food out of the pipes eaten. one pipe. Maybe supply more ED? 25 Jan Gentoo penguins Air bubbles Two diving bottles are to be placed Structural Stimulate exploratory The penguins should go into The entire group reacted Enrichment A1 2019, Pygoscelis papua at the bottom of the tank and then behaviour and the water within 5 mins of the as expected, although 3 should be 1230, DA opened. This involves diving. Facilities increase physical bubbles appearance, should were more reluctant to less than with an inbuilt bubble system can just excercise not be afraid of them, but circle go into the water, it took 20 mins, turn it on (15-20 mins). around them and try to hunt them 7 mins to dive in. otherwise them with the beaks. Some the animals might let them caress their lose interest. bodies (spa like). https://doi.org/10.19227/jzar.v9i4.588 Journal of Zoo and Aquarium Research 9(4) 2021 Table 1. Action, goal and expected reactions to enrichment (continued). Date, time, Species ED Action Enrichment Goal Expected reaction Obtained reaction Comments Evaluation who type 29 Jan Arctic char Salvelinus Food ball 50% of their daily diet is placed inside Nutritional Increase foraging time The animals should swim towards the All animals went Animals F10 2019, alpinus, stickleback a perforated ball and put in the tank. and and stimulate olfactory food ball(s) and start pushing them into hiding and did were 1130, CZ Gasterosteus It should be fixed to stay in the mid- structural senses. to get the food. None of the animals not explore the ED scared of aculeatus, column or deeper; avoid the surface should be left separated from the group. in the given time. the ED rudd Scardinius to prevent fish gulping air. One erythrophthalmus , ball is sufficient for a small group, Nase Chondrostoma but increase the number with fish https://doi.org/10.19227/jzar.v9i4.588 nasus numbers (10 mins). 31 Jan Mediterranean moray PVC pipe Place a PVC pipe in the corner of the Structural Stimulate exploratory Moray eel should start exploring the Whilst the moray Maybe D5 2019, eel Muraena helena fitted on tank; ensure its diametre is bigger and sensory behaviour, provide device and go in and out several times, eel showed interest extend Journal of Zoo and Aquarium Research 9(4) 2021 1330, DA the inside than a moray eel and twice as long. different hiding/ even stay in it for an extended period and explored the allotted with fake Put it into the display prior to feeding shelter places, give of time. pipe, it did not time? algae or time. Leave for about 2 hrs. different substrates to go in. artificial choose from, alter the grass environment for a short duration of time. 06 Mar Pacus and Cardinal Ice bomb Freeze 25% of the daily diet in Sensory and Increase exploratory Animals should appraoch the ice bombs All animals Rapid A1 2019, fish ice balls, pieces of fish can stick structural behaviour. Allow and attempt to feed from them, push approached the melting. 1245, CS out of the bomb; ensure balls are access to floating food them and then as they melt take the bombs immediately Next time sufficiently big that they can’t be items and exposure to food. No aggreession should be seen or and pushed them a higher swallowed whole. At least one bomb different textures. more bombs will be needed. all over the tank. amount per fish should be provided on the All the food is of ED surface of the water simulataneously, consumed. outside of feeding time (15 mins). 14 Mar big bellied seahorse Live mysis Place live mysis inside a transparent Nutritional, Increase foraging time, Seahorses and small tropical fish should High success. Seahorses A1 2019, H. Abdominalis inside a bottle that has one hole on the top. structural stimulate exploratory go near the bottle and discover the might need 1130, CS garden eels bottle Tie it to a weight and place it in the and behaviour. mysis leave through it’s hole and hunt more time. Heteroconger hassi, tank in mid water. Animals can see cognitive them. Fish might bump the bottle Goal-oriented environmental enrichment in aquarium species small tropical reef the mysis moving inside the ED (20 to stimulate the mysis to come out. fish species, discus mins). Garden eels will wait for the mysis to Symphysodon discus leave the bottle and then forage for them in the substrate. 05 Apr poison dart frog Live Place live drosophila inside a Nutritional, Increase foraging time, Frogs should approach the ED within High success. Not more A1 2019, Phyllobates terribilis drosophila transparent bottle with several holes structural stimulate exploratory 5 mins of it being introduced and start time 1530, RP inside a on its lid. Place it in the middle of and behaviour and bumping it with their head and/or needed bottle the terrarium, away from plants and cognitive cognitive abilities to try tongue to try and get the flies out. All water (30 mins). and get the flies out of the flies should be eaten in 30 mins. the bottle. 10 Apr Gentoo penguins Water jet Place two hoses or water jets in the Sensory and Allow the penguins The entire colony should go under or to All animals ended A1 2019, Pygoscelis papua exhibit, at the rim of the pool and structural to feel different the side of the jets/sprays and play with up going under the 1000, DA spraying towards it. Both should have water pressures to the water, letting it fall on their bodies. water jets, some different pressures (15 mins). rub against. Increase Penguins to roll and groom themselves seemed to enjoy it exploratory behaviour underneath the water. more than others. and physical excercise. 277 Monreal-Pawlowsky et al. Additionally, and to allow future statistical analysis of the Consequences implemented enrichment programme through a distance matrix, a given factor was assigned to each reaction category (Figure 2) The methodology described above has been followed over the from 1 for ‘expected reaction’ to 10 for ‘negative’ reaction. These last six years at regular intervals in all participating facilities and analyses allow a readjustment of the enrichment devices used to with a broad range of species. It is expected that the defined assure efficacy. validated catalogues of enrichment devices will be an important tool facilitating the stimulation of particular species-specific 6. Creation of a validated catalogue of proven and goal- behaviours. For example, the use of enrichment devices such orientated enrichment devices as feeding pipes for rays (Raja clavata, R. montagui and R. undulata) has proven useful in stimulating their sensory organs Based on pilot studies and initial developments, it has been and encouraging a foraging behaviour that they would exhibit in possible to develop catalogues of enrichment devices for various the wild (Feist and Anderson 1991; Anderson and Wood 2001; aquatic animals. An example of those enrichment devices obtained Borneman 2009; Corcoran 2015). While using this enrichment from validated catalogues for several species can be found in Table item, the expected reaction was consistently observed and 2. recorded, and it is advised to implement this enrichment when Table 2. Examples of validated enrichment devices for different aquarium species Species Enrichment device Enrichment type Goals Behaviours Panilurus elephas spiny Feeding rings Nutritional Increase time species spend looking for Foraging behavioural lobster food/obtaining food. Possibility of choice diversity over the food. Pagurus sp. hermit Different substrates with or Sensory Increase exploratory time and foraging Foraging, locomotory crabs without embedded food behaviour. Possibility of choice over and sensory behavioural different substrates. diversity Chelonia mydas green Brush Social and Choices for interaction with professional Exploratory, sensory and sea turtle sensory care staff. Choices for exploratory and locomotory behavioural sensorial body interactions. diversity Pygoscelis papua Air bubbles Structural To motivate exploratory behaviour and Exploratory and locomotory Gentoo penguin increase physical exercise. behavioural diversity Salvelinus alpinus Food ball Nutritional, Increase time species spend looking for Foraging, locomotory and Arctic char structural and food/obtaining food. Possibility of choice social interactions social over the food. Socio interactions between individuals. Muraena helena Food pipe Nutritional, Increase time species spend looking for Foraging, locomotory, Mediterranean moray structural, food/obtaining food. Possibility of choice exploratory and social eel sensory and over the food. Socio interactions between behaviours cognitive individuals. Pacus and cardinal fish Food "bombs" Nutritional and Increase time species spend looking for Foraging, exploratory and sensory food/obtaining food. Possibility of choice locomotory behavioural over the food. diversity Hippocampus Alive Mysis inside a bottle Nutritional and Increase time species spend looking for Foraging, exploratory and abdominalis big belly structural food/obtaining food. Possibility of choice locomotory behavioural seahorse over the food. diversity Phyllobates terribilis Alive Drosophila in the Nutritional, Increase time species spend looking for Foraging, exploratory and poison frog bottle structural and food/obtaining food. Possibility of choice locomotory behavioural cognitive over the food. diversity Diodon sp. puffer fish Mussels glued together Nutritional and Increase time species spend looking for Foraging, exploratory and with coral paste and shells sensory food/obtaining food. Possibility of choice locomotory behavioural filled with omnivore gel over the food. diversity Salmonids Underwater currents Structural and Stimulate group cohesion and physical Social and locomotory sensory exercise. behavioural diversity Octopus vulgaris Pipe maze Structural and Stimulate exploration and physical exercise. Exploratory and locomotory common octopus sensory behavioural diversity Hommarus gammarus Pipe with holes Sensory and Olfactory stimulation and looking for food/ Exploratory and foraging European lobster nutritional obtaining food. behavioural diversity Electrophorus Rain Sensory Stimulate exploration and hunting Exploratory and locomotory electricus electric eel behaviour. behavioural diversity 278 Journal of Zoo and Aquarium Research 9(4) 2021 https://doi.org/10.19227/jzar.v9i4.588 Goal-oriented environmental enrichment in aquarium species the resulting behaviour is sought. Also, the provision of feeding natural behaviours can be stimulated with man-made objects containers for lobsters (Homarus gammarus), hidden in sand, in an array of aquatic species. The validated species catalogues stimulated the desired effect in the lobster. As observed in nature, created from standardised observations enable the identification the lobster dug out the device and found a way of obtaining the and validation of enrichment devices that stimulate certain food inside using its claws. Similar enrichment protocols and behaviours under known conditions (number of sessions, devices were developed for starfish (Asterias rubens), increasing duration, etc.). Determining which behaviours are missing from foraging behaviour and feeding time up to five times, although any behavioural repertoire of a group of animals or an individual more research is warranted with this group since the reactions animal, it is possible to determine which enrichment devices to of tropical versus cold water species has not been yet compared. use to stimulate behaviours with a positive welfare influence . Artificial rain was provided to trigger hunting behaviour in an electric eel (Electrophorus electricus), by combining the trickle of Acknowledgements water with food being supplied on the surface. This encouraged The authors would like to thank the staff of Barcelona Zoo (Spain), the performance of a natural behaviour, in this case hunting, and Mundomar (Spain), CRAM (Spain), Parc Asterix (France), Attica releasing electricity throughout the whole process. An aquatic Park (Greece), the seven SeaLife’s in Germany, especially David mantis shrimp (Odontodactylus scyllarus) was offered different García and his team in Konstanz, SeaLife Helsinki (Finland), SeaLife substrates to build its nest, hence increasing choice and control Gardaland and SeaLife Jesolo (Italy) for taking the time and effort over its environment. Sticklebacks (Gasterosteus aculeatus) were to implement this method in their facilities. offered a floating food ball to allow for longer feeding times; this intervention has worked every time it has been implemented, References which is over 20 times to date. Allard S., Bashaw M. (2019) Empowering Zoo Animals. In A. Kaufman, M. In grazing fish that swim in schools it is very important to Bashaw, & T. Maple (Eds.), Scientific Foundations of Zoos and Aquariums: offer several grazing stations, as nutritional enrichment devices, Their Role in Conservation and Research (pp. 241–273). 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