Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and acti... more Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and actively interact with preferred social partners. Being able to detect cues and signals produced by conspecifics is vital in enabling social behavior. Many elasmobranch species communicate via body and fin postures, but it is not yet known if or how mobulid rays communicate or respond to cues produced by conspecifics. These rays have specialized cephalic lobes that are highly flexible and used in feeding, but may have other functions such as gestural communication. In this study, we developed a standardized method to assess manta ray behavior in the wild via focal sampling and frame-by-frame video analysis. From observations recorded at cleaning stations in Raja Ampat, West Papua, we described various types of cephalic lobe positioning and movements made by free-ranging M. alfredi and investigated these in different behavioral contexts. We found that cephalic lobe curls were modulated when approaching both conspecifics and human divers, as well as during interactions with cleaner fish, suggesting that these lobes may be used in sensing water movements, olfactory sensing, and/or gestural communication. Cephalic lobes were moved independently of one another, but we found no evidence of individual laterality. The lack of chemosensory capacity on the lobes suggests that gestural communication is the most likely function, but further research is required to determine this. These results are informative in understanding the function of gestural communication in manta ray social interactions and add to our growing understanding of elasmobranchs’ sophisticated social behavior. Social animals rely on communication and cues produced by conspecifics to respond to opportunities and threats. Many elasmobranch species use body and fin postures as gestural signals during competitive, courtship, and other social interactions. Reef manta rays (Mobula alfredi) are social elasmobranchs that form groups in near-shore, shallow water habitats. They possess paired, flexible cephalic lobes positioned on the side of the head which are specialized for feeding but may have a variety of functions. Here, we describe, quantify, and suggest likely explanations for the movement and positioning of cephalic lobes during various manta ray social behaviors, including conspecific, human, and cleaner fish interactions. Our results suggest that lobe movements may be used in detecting water movements, olfactory sensing, and/or gestural communication, and are an important aspect of social behavior in this species.
The majority of commentaries are supportive of our position on the scepticism that muddies the wa... more The majority of commentaries are supportive of our position on the scepticism that muddies the waters surrounding fish pain and sentience. There is substantial empirical evidence for pain in fish. Animals' experience of pain cannot be compared to artificial intelligence (AI) because AI can only mimic responses to nociceptive input on the basis of human observations and programming. Accepting that fish are sentient would not be detrimental to the industries reliant on fish. A more proactive discussion between scientists and stakeholders is needed to improve fish welfare for the benefit of all.
Don't be fooled by their lack of expression. Behavioural ecologists Culum Brown and Catarina ... more Don't be fooled by their lack of expression. Behavioural ecologists Culum Brown and Catarina Vila Pouca reveal fish to be thinking, feeling animals that deserve a better deal.
Fish models are increasingly used in a wide variety of experimental contexts and their adoption i... more Fish models are increasingly used in a wide variety of experimental contexts and their adoption is growing globally. This chapter reviews the evidence for sentience and cognitive abilities in fishes to highlight the growing empirical evidence of the mental capacities of fish. The definition of sentience is presented along with the scientific data pertinent to understanding what fishes are capable of, as well as higher order cognitive abilities such as numerical skills and the capacity for learning and memory. Being able to experience positive and negative welfare states such as pain, fear, and stress is highly debated for fishes; thus this chapter reviews the evidence for and arguments against conscious perception of pain and fear. If suffering and sentience are accepted in fishes, this has ethical implications for the way in which we use fish in scientific studies.
Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal,... more Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal, and/or trophic strategies. Fishes living in the intertidal zone demonstrate highly adaptive plastic behaviour, including resource partitioning, through spatial and temporal shifts in diet and micro-habitat. Although intertidal fish assemblages are influenced by inter- and intraspecific competition, few studies have compared the extent of resource partitioning between sympatric species in the context of trophic niche plasticity. Here we used complementary approaches, stomach content and stable isotope (δ13 C and δ15 N) analyses, to evaluate seasonal and growth shifts in trophic niche position in two sympatric (Favonigobius lentiginosus and Bathygobius krefftii), and one allopatric (Bathygobius cocosensis) species of intertidal goby. Our results indicate that resource partitioning in the two sympatric species varied with season, with almost no trophic niche overlap in summer to a ~ 30% overlap in winter. We also found evidence of dietary changes in B. cocosensis, which is likely associated with a shift in micro-habitat and intraspecific competition. Our findings highlight the temporal range of behavioural plasticity in trophic niche position of intertidal gobies, which likely has high adaptive value in the dynamic intertidal zone.
The field of animal personality has received considerable attention in past decades, yet few stud... more The field of animal personality has received considerable attention in past decades, yet few studies have examined personality in the wild. This study investigated docility, a measure of boldness, in two Port Jackson shark (Heterodontus portusjacksoni) populations using field tests, and if laterality differences explained docility levels. We developed a struggle test as an assay for docility, which is particularly amenable to field studies. The struggle test was effective, and repeatable inter-individual docility differences were observed. Sex, but not population, influenced docility scores, with male sharks being less docile than females. This difference is likely due to the contrasting role each sex plays during mating. We also found individualized lateralization. However, no individual-level relationship between lateralization and docility was detected. Despite reported links between laterality and some personality traits, the relationship between laterality and boldness remains ...
European Association of Zoos and Aquaria (EAZA), Oct 31, 2017
Elasmobranches are popular animals in public aquariums. Worldwide more than 700 million people vi... more Elasmobranches are popular animals in public aquariums. Worldwide more than 700 million people visit zoos and aquariums annually, enabling elasmobranches to become an important ambassador for their natural habitats. We conducted a census within the European Association of Zoos and Aquaria to gain a better overview of which species are present within European collections. The census showed that 102 chondrichthyan species are found in European zoos and public aquaria, accounting for 8,6% of all known species. Of the captive population 47.1% of species have reproduced in aquariums. Benthic species are found most commonly in aquariums. Of the species reproducing, 87.8% fall in the body size range of 51 to 250 cm. Categorising the reproductive results by reproductive mode, the most successful groups are oviparous and aplacental viviparous with uterine villi or trophonemata. A regional collection plan has been defined by using the results of the census and the IUCN status. Currently 42 species are managed by a species coordinator, within the ex-situ European elasmobranch population to ensure a genetically healthy population, to increase reproductive output, and to conduct husbandry research. Long-term breeding efforts will help to reduce the demand on wild populations to supply the aquarium population. Species coordinators will become the contact for in-situ conservation initiatives and international conservation bodies like IUCN. This study discusses further the future challenges in the captive management of chondrichthyan populations.
Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and acti... more Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and actively interact with preferred social partners. Being able to detect cues and signals produced by conspecifics is vital in enabling social behavior. Many elasmobranch species communicate via body and fin postures, but it is not yet known if or how mobulid rays communicate or respond to cues produced by conspecifics. These rays have specialized cephalic lobes that are highly flexible and used in feeding, but may have other functions such as gestural communication. In this study, we developed a standardized method to assess manta ray behavior in the wild via focal sampling and frame-by-frame video analysis. From observations recorded at cleaning stations in Raja Ampat, West Papua, we described various types of cephalic lobe positioning and movements made by free-ranging M. alfredi and investigated these in different behavioral contexts. We found that cephalic lobe curls were modulated when approaching both conspecifics and human divers, as well as during interactions with cleaner fish, suggesting that these lobes may be used in sensing water movements, olfactory sensing, and/or gestural communication. Cephalic lobes were moved independently of one another, but we found no evidence of individual laterality. The lack of chemosensory capacity on the lobes suggests that gestural communication is the most likely function, but further research is required to determine this. These results are informative in understanding the function of gestural communication in manta ray social interactions and add to our growing understanding of elasmobranchs’ sophisticated social behavior. Social animals rely on communication and cues produced by conspecifics to respond to opportunities and threats. Many elasmobranch species use body and fin postures as gestural signals during competitive, courtship, and other social interactions. Reef manta rays (Mobula alfredi) are social elasmobranchs that form groups in near-shore, shallow water habitats. They possess paired, flexible cephalic lobes positioned on the side of the head which are specialized for feeding but may have a variety of functions. Here, we describe, quantify, and suggest likely explanations for the movement and positioning of cephalic lobes during various manta ray social behaviors, including conspecific, human, and cleaner fish interactions. Our results suggest that lobe movements may be used in detecting water movements, olfactory sensing, and/or gestural communication, and are an important aspect of social behavior in this species.
The majority of commentaries are supportive of our position on the scepticism that muddies the wa... more The majority of commentaries are supportive of our position on the scepticism that muddies the waters surrounding fish pain and sentience. There is substantial empirical evidence for pain in fish. Animals' experience of pain cannot be compared to artificial intelligence (AI) because AI can only mimic responses to nociceptive input on the basis of human observations and programming. Accepting that fish are sentient would not be detrimental to the industries reliant on fish. A more proactive discussion between scientists and stakeholders is needed to improve fish welfare for the benefit of all.
Don't be fooled by their lack of expression. Behavioural ecologists Culum Brown and Catarina ... more Don't be fooled by their lack of expression. Behavioural ecologists Culum Brown and Catarina Vila Pouca reveal fish to be thinking, feeling animals that deserve a better deal.
Fish models are increasingly used in a wide variety of experimental contexts and their adoption i... more Fish models are increasingly used in a wide variety of experimental contexts and their adoption is growing globally. This chapter reviews the evidence for sentience and cognitive abilities in fishes to highlight the growing empirical evidence of the mental capacities of fish. The definition of sentience is presented along with the scientific data pertinent to understanding what fishes are capable of, as well as higher order cognitive abilities such as numerical skills and the capacity for learning and memory. Being able to experience positive and negative welfare states such as pain, fear, and stress is highly debated for fishes; thus this chapter reviews the evidence for and arguments against conscious perception of pain and fear. If suffering and sentience are accepted in fishes, this has ethical implications for the way in which we use fish in scientific studies.
Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal,... more Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal, and/or trophic strategies. Fishes living in the intertidal zone demonstrate highly adaptive plastic behaviour, including resource partitioning, through spatial and temporal shifts in diet and micro-habitat. Although intertidal fish assemblages are influenced by inter- and intraspecific competition, few studies have compared the extent of resource partitioning between sympatric species in the context of trophic niche plasticity. Here we used complementary approaches, stomach content and stable isotope (δ13 C and δ15 N) analyses, to evaluate seasonal and growth shifts in trophic niche position in two sympatric (Favonigobius lentiginosus and Bathygobius krefftii), and one allopatric (Bathygobius cocosensis) species of intertidal goby. Our results indicate that resource partitioning in the two sympatric species varied with season, with almost no trophic niche overlap in summer to a ~ 30% overlap in winter. We also found evidence of dietary changes in B. cocosensis, which is likely associated with a shift in micro-habitat and intraspecific competition. Our findings highlight the temporal range of behavioural plasticity in trophic niche position of intertidal gobies, which likely has high adaptive value in the dynamic intertidal zone.
The field of animal personality has received considerable attention in past decades, yet few stud... more The field of animal personality has received considerable attention in past decades, yet few studies have examined personality in the wild. This study investigated docility, a measure of boldness, in two Port Jackson shark (Heterodontus portusjacksoni) populations using field tests, and if laterality differences explained docility levels. We developed a struggle test as an assay for docility, which is particularly amenable to field studies. The struggle test was effective, and repeatable inter-individual docility differences were observed. Sex, but not population, influenced docility scores, with male sharks being less docile than females. This difference is likely due to the contrasting role each sex plays during mating. We also found individualized lateralization. However, no individual-level relationship between lateralization and docility was detected. Despite reported links between laterality and some personality traits, the relationship between laterality and boldness remains ...
European Association of Zoos and Aquaria (EAZA), Oct 31, 2017
Elasmobranches are popular animals in public aquariums. Worldwide more than 700 million people vi... more Elasmobranches are popular animals in public aquariums. Worldwide more than 700 million people visit zoos and aquariums annually, enabling elasmobranches to become an important ambassador for their natural habitats. We conducted a census within the European Association of Zoos and Aquaria to gain a better overview of which species are present within European collections. The census showed that 102 chondrichthyan species are found in European zoos and public aquaria, accounting for 8,6% of all known species. Of the captive population 47.1% of species have reproduced in aquariums. Benthic species are found most commonly in aquariums. Of the species reproducing, 87.8% fall in the body size range of 51 to 250 cm. Categorising the reproductive results by reproductive mode, the most successful groups are oviparous and aplacental viviparous with uterine villi or trophonemata. A regional collection plan has been defined by using the results of the census and the IUCN status. Currently 42 species are managed by a species coordinator, within the ex-situ European elasmobranch population to ensure a genetically healthy population, to increase reproductive output, and to conduct husbandry research. Long-term breeding efforts will help to reduce the demand on wild populations to supply the aquarium population. Species coordinators will become the contact for in-situ conservation initiatives and international conservation bodies like IUCN. This study discusses further the future challenges in the captive management of chondrichthyan populations.
Recent empirical studies have reported evidence that many aquatic species, including fish,
cephal... more Recent empirical studies have reported evidence that many aquatic species, including fish, cephalopods and crustaceans, have the capacity for nociception and pain, and that their welfare should be taken into consideration. Some sceptics, rejecting the precautionary principle, have denied that any study demonstrates pain or other aspects of sentience in fish. This target article discusses some of the scientific shortcomings of these critiques through a detailed analysis of a study exploring nociception and analgesia in larval zebrafish. Sneddon, L.U., Lopez-Luna, J., Wolfenden, D.C.C., Leach, M.C., Valentim, A.M. Steenbergen, P.J., Bardine, N., Currie, A.D., Broom, D.M. and Brown, C.
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Papers by Culum Brown
cephalopods and crustaceans, have the capacity for nociception and pain, and that their welfare should be taken
into consideration. Some sceptics, rejecting the precautionary principle, have denied that any study
demonstrates pain or other aspects of sentience in fish. This target article discusses some of the scientific
shortcomings of these critiques through a detailed analysis of a study exploring nociception and analgesia in larval zebrafish.
Sneddon, L.U., Lopez-Luna, J., Wolfenden, D.C.C., Leach, M.C., Valentim, A.M. Steenbergen, P.J., Bardine, N., Currie, A.D., Broom, D.M. and Brown, C.