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Vejřík L, Vejříková I, Blabolil P, Bartoň D, Sajdlová Z, Kočvara L, Peterka J, Muška M, Duras J, Jůza T, Ribeiro F, Rivaes R, Ribeiro D, Castro B, Moncada M, Čech M. Long-lines for research monitoring and efficient population regulation of an invasive apex predator, European catfish ( Silurus glanis). Heliyon 2024; 10:e34125. [PMID: 39100468 PMCID: PMC11296022 DOI: 10.1016/j.heliyon.2024.e34125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 08/06/2024] Open
Abstract
European catfish is a large-bodied apex predator, a key species in native areas, but invasive in others where it negatively impacts local aquatic fauna necessitates catfish regulation. However, traditional ichthyological methods face challenges in capturing it. The study presents a detailed description of the efficient long-line method, refined through 48 sampling campaigns across twelve European water bodies. This method proves cost-effective and technically undemanding, requiring an average of 5.6 bait fish to catch one European catfish per day. The long-lines outperform other techniques, with the highest Biomass per unit effort (BPUE) of 6.205 kg of catfish per man-hour and minimal by-catch (0.276 kg per man-hour). In contrast, fyke nets, the second most efficient method, achieve a BPUE of 0.621 kg of catfish per man-hour with 3.953 kg of by-catch per man-hour. To optimize long-line catches, a 15 m distance between branch lines and regular relocation is recommended. Live fish is the most effective bait with no significant differences observed among species. However, earthworms, a less controversial alternative, are also efficient, especially for smaller catfish. Our recapture approach using various ichthyological methods revealed no hook avoidance behavior by catfish after a previous catch or avoidance by a certain part of the population. The long-line method is suitable for population regulation, scientific research, and conservation efforts and is the most effective means of capturing live European catfish.
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Affiliation(s)
- Lukáš Vejřík
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Ivana Vejříková
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Petr Blabolil
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
- University of South Bohemia in České Budějovice, Faculty of Science, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Daniel Bartoň
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Zuzana Sajdlová
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Luboš Kočvara
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Jiří Peterka
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Milan Muška
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Jindřich Duras
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodňany, Czech Republic
- Department of Water Management Planning, Vltava River Authority, State Enterprise, Plzeň, Czech Republic
| | - Tomáš Jůza
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - Filipe Ribeiro
- MARE—Marine and Environmental Sciences Centre/ARNET—Aquatic Research Network, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Rui Rivaes
- MARE—Marine and Environmental Sciences Centre/ARNET—Aquatic Research Network, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Diogo Ribeiro
- MARE—Marine and Environmental Sciences Centre/ARNET—Aquatic Research Network, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Beatriz Castro
- MARE—Marine and Environmental Sciences Centre/ARNET—Aquatic Research Network, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Mafalda Moncada
- MARE—Marine and Environmental Sciences Centre/ARNET—Aquatic Research Network, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Martin Čech
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005, České Budějovice, Czech Republic
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Silveira MM, Donelson JM, McCormick MI, Araujo-Silva H, Luchiari AC. Impact of ocean warming on a coral reef fish learning and memory. PeerJ 2023; 11:e15729. [PMID: 37576501 PMCID: PMC10416774 DOI: 10.7717/peerj.15729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 06/18/2023] [Indexed: 08/15/2023] Open
Abstract
Tropical ectotherms are highly sensitive to environmental warming, especially coral reef fishes, which are negatively impacted by an increase of a few degrees in ocean temperature. However, much of our understanding on the thermal sensitivity of reef fish is focused on a few traits (e.g., metabolism, reproduction) and we currently lack knowledge on warming effects on cognition, which may endanger decision-making and survival. Here, we investigated the effects of warming on learning and memory in a damselfish species, Acanthochromis polyacanthus. Fish were held at 28-28.5 °C (control group), 30-30.5 °C (moderate warming group) or 31.5-32 °C (high warming group) for 2 weeks, and then trained to associate a blue tag (cue) to the presence of a conspecific (reward). Following 20 training trials (5 days), fish were tested for associative learning (on the following day) and memory storage (after a 5-days interval). The control group A. polyacanthus showed learning of the task and memory retention after five days, but increasing water temperature impaired learning and memory. A thorough understanding of the effects of heat stress, cognition, and fitness is urgently required because cognition may be a key factor determining animals' performance in the predicted scenario of climate changes. Knowing how different species respond to warming can lead to better predictions of future community dynamics, and because it is species specific, it could pinpoint vulnerable/resilience species.
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Affiliation(s)
- Mayara M. Silveira
- Department of Physiology and Behavior, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Jennifer M. Donelson
- ARC Centre of Excellence for Coral Reef Studies, James Cook University of North Queensland, Townville, Australia
| | | | - Heloysa Araujo-Silva
- Department of Physiology and Behavior, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Ana C. Luchiari
- Department of Physiology and Behavior, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
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Long J, Fu S. Spatial Learning of Individual Cichlid Fish and Its Effect on Group Decision Making. Animals (Basel) 2022; 12:1318. [PMID: 35625164 PMCID: PMC9137809 DOI: 10.3390/ani12101318] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/15/2022] [Accepted: 05/19/2022] [Indexed: 12/04/2022] Open
Abstract
Learning and memory abilities and their roles in group decision-making have important ecological relevance in routine activities such as foraging and anti-predator behaviors in fish species. The aims of the present study were to explore individual spatial learning abilities of juvenile cichlids (Chindongo demasoni) in a foraging context, and to explore the influence of heterogeneity of memory information among group members on group performance in a six-arm radiation maze. In the context of an association between landmarks and food, learning ability was evaluated by the speed and accuracy of reaching the arm with food during seven days of reinforcement, and memory retention was tested at intervals of 2, 5, 8 and 11 days of detraining. Then, the speed and accuracy of an eight-member group with different proportions of memory-trained fish were measured. Both speed and accuracy of individual fish improved significantly and linearly in the first five days of training and leveled off between five and seven days, with values 60% shorter (in speed) and 50% higher (in accuracy) compared to those of the first day. Neither speed nor accuracy showed any decrease after 11 days of detraining, suggesting memory retention of the spatial task. When measured in a group, the speed and accuracy of the majority of the group (more than half) in reaching the arm with food changed linearly with an increasing ratio of trained members. This shows that cichlids can acquire associative learning information through a training process, and group behavior of cichlids seems not likely be determined by a minority of group members under a foraging context.
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Affiliation(s)
| | - Shijian Fu
- Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing 401331, China;
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Fuss T, Schluessel V. Something worth remembering: visual discrimination in sharks. Anim Cogn 2014; 18:463-71. [PMID: 25359522 DOI: 10.1007/s10071-014-0815-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 10/20/2014] [Accepted: 10/20/2014] [Indexed: 11/25/2022]
Abstract
This study investigated memory retention capabilities of juvenile gray bamboo sharks (Chiloscyllium griseum) using two-alternative forced-choice experiments. The sharks had previously been trained in a range of visual discrimination tasks, such as distinguishing between squares, triangles and lines, and their corresponding optical illusions (i.e., the Kanizsa figures or Müller-Lyer illusions), and in the present study, we tested them for memory retention. Despite the absence of reinforcement, sharks remembered the learned information for a period of up to 50 weeks, after which testing was terminated. In fish, as in other vertebrates, memory windows vary in duration depending on species and task; while it may seem beneficial to retain some information for a long time or even indefinitely, other information may be forgotten more easily to retain flexibility and save energy. The results of this study indicate that sharks are capable of long-term memory within the framework of selected cognitive skills. These could aid sharks in activities such as food retrieval, predator avoidance, mate choice or habitat selection and therefore be worth being remembered for extended periods of time. As in other cognitive tasks, intraspecific differences reflected the behavioral breadth of the species.
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Affiliation(s)
- Theodora Fuss
- Institute of Zoology, Rheinische Friedrich-Wilhelms-University Bonn, Meckenheimer Allee 169, 53115, Bonn, Germany,
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