1
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Rodger JR, Guthrie J, Honkanen HM, Lothian AJ, Lilly J, Walters M, Miller R, Hawkins L, Reeve A, Ribbens J, Henderson J, Parke D, Green A, Shields BA, Ramsden P, Fletcher M, Kettle-White A, Shaw B, Burns S, Laughton R, Conroy C, Daphne C, Williams K, Robertson S, Bean CW, Del Villar D, Waters C, Rosell R, Cotter D, Smith M, Maoiléidigh NÓ, Kennedy R, Adams CE. Determinants of riverine migration success by Atlantic salmon (Salmo salar) smolts from rivers across the UK and Ireland. JOURNAL OF FISH BIOLOGY 2024. [PMID: 39129462 DOI: 10.1111/jfb.15884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 07/08/2024] [Accepted: 07/12/2024] [Indexed: 08/13/2024]
Abstract
There is some evidence that the river migration success of Atlantic salmon smolts, on their first migration to sea, varies both spatially and temporally. However, we have only a poor understanding of what may be driving this variation. In this study, we used acoustic telemetry to quantify the spatial and temporal variations in river migration success in Atlantic salmon smolts on their first migration to sea. In total 4120 Atlantic salmon smolts migrating through 22 rivers in Scotland, England, Ireland, and Northern Ireland over multiple years were included in the study. Individuals were defined as successful migrants if detected leaving the river to enter marine waters. The results show significant temporal (up to 4 years) and spatial (river) variations in migration success, with overall between-river migration success varying from 3.4% to 97.0% and between years from 3.4% and 61.0%. Temporal variation in migration success was river specific, with some rivers being more temporally stable (exhibiting little variation between years) than others. Across all rivers and years, individual migration success was predicted positively by body condition and negatively by tag burden. The rate of migration success for a population (migration success standardized to a common river distance [proportion km-1]) was predicted by a number of environmental factors. The proportion of river catchment that comprised wetland and woodland positively predicted migration success, whereas the proportion of grassland and peatland in a catchment negatively predicted the rate of migration success. Although the mechanisms through which these effects may be operating were not directly examined in this study, we discuss some potential routes through which they may occur.
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Affiliation(s)
- Jessica R Rodger
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Atlantic Salmon Trust, Perth, UK
| | - Jemma Guthrie
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Hannele M Honkanen
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Angus J Lothian
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Atlantic Salmon Trust, Perth, UK
| | - Jessie Lilly
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Northwest Atlantic Fisheries Centre, St Johns, Newfoundland, Canada
| | - Marcus Walters
- The Deveron, Bogie and Isla Rivers Charitable Trust, Avochie, UK
| | - Richie Miller
- The Deveron, Bogie and Isla Rivers Charitable Trust, Avochie, UK
| | | | - Al Reeve
- Dee District Salmon Fishery Board, Aboyne, UK
| | | | - Jim Henderson
- The Nith Catchment Fishery Trust and Nith District Salmon Fishery Board, Dumfries, UK
| | - Debbie Parke
- The Nith Catchment Fishery Trust and Nith District Salmon Fishery Board, Dumfries, UK
| | - Amy Green
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | | | | | | | | | - Brian Shaw
- The Ness District Salmon Fishery Board, Beauly House, Dochfour Business Centre, Inverness, UK
| | | | | | | | - Chris Daphne
- The Ness District Salmon Fishery Board, Beauly House, Dochfour Business Centre, Inverness, UK
| | | | | | - Colin W Bean
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | | | | | - Robert Rosell
- Agri-food and Biosciences Institute, River Bush Salmon Station, Bushmills, UK
| | | | | | | | - Richard Kennedy
- Agri-food and Biosciences Institute, River Bush Salmon Station, Bushmills, UK
| | - Colin E Adams
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
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2
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Kennedy RJ, Barry J, Boyd A, Allen M. Does phenology influence predation rate on Salmo trutta parr during lake migration? JOURNAL OF FISH BIOLOGY 2024. [PMID: 38491848 DOI: 10.1111/jfb.15719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 03/18/2024]
Abstract
Acoustic tags fitted with predation sensors, which trigger following ingestion by piscivorous predators, were used to compare direct predation rates during downstream migration (out-migration) of potamodromous (freshwater) brown trout (Salmo trutta L.) parr from their natal river into a large freshwater lake system during spring and autumn. Thirty-eight spring migrants were tagged across two study years (2021 and 2022) of which 13 individuals (34%) were predated. By contrast 40 autumn migrants were tagged (2020 and 2021) of which three individuals (7.5%) experienced predation. The overall predation loss rate for spring migrants was 0.342% day-1 and was 0.075% day-1 for autumn migrants. Most predation events during spring (77%) occurred within the lower river before tagged fish entered the lake, whilst no predation events were recorded within the river in the autumn. Predation events were significantly linked to tagging season (spring or autumn), with the probability of tags remaining untriggered (as a proxy for survival) being higher 93% (95% confidence interval [CI] [87%, 100%]) in autumn than in spring 66% (95% CI [53%, 83%]). The spring migration periods showed significantly lower river discharge (0.321 m3 /s mean daily discharge, April 1 to May 31) to those measured during autumn (1.056 m3 /s mean daily discharge, October 1 to November 30) (Mann-Whitney U-test, U = 1149, p < 0.001). Lower flows, clearer water, and longer sojourn in the river may have contributed to greater predation losses in the spring relative to the autumn.
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Affiliation(s)
| | | | - Adele Boyd
- Agri-Food & Biosciences Institute, Belfast, Northern Ireland
| | - Michelle Allen
- Agri-Food & Biosciences Institute, Belfast, Northern Ireland
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3
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Waters C, Cotter D, O'Neill R, Drumm A, Cooney J, Bond N, Rogan G, Maoiléidigh NÓ. The use of predator tags to explain reversal movement patterns in Atlantic salmon smolts (Salmo salar L.). JOURNAL OF FISH BIOLOGY 2024. [PMID: 38226528 DOI: 10.1111/jfb.15658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/17/2024]
Abstract
Acoustic telemetry has seen a rapid increase in utility and sophistication in recent years and is now used extensively to assess the behavior and survival rates of many aquatic animals, including the Atlantic salmon. As part of the salmon's complex life cycle, salmon smolts are thought to make a unidirectional migration from fresh water to the sea, which is initiated by changes in their physiology. However, some tag movement patterns do not conform with this and can be difficult to explain, particularly if the tagged fish has been eaten by a predator. This study combines the use of predator tags with machine learning techniques to understand the fate of migrating salmon smolts and thereby improve estimates for migration success. Over 3 years between 2020 and 2022, 217 salmon smolts (including wild and hatchery-reared ranched fish) were acoustically tagged and released into an embayment on the west coast of Ireland. Some tagged smolts were observed to return from the estuary back into a saline lagoon through which they had already migrated. To distinguish between the movement of a salmon smolt and that of a predator, predator tags were deployed in migrating smolts in 2021 and 2022. The addition of a temperature sensor in 2022 enabled the determination of predator type causing the returning movement. A significant number of predator tags were triggered, and the patterns of movement associated with these triggered tags were then used with two types of machine learning algorithms (hierarchical cluster analysis and random forest) to identify and validate the behavior of smolts tagged without extra sensors. Both models produced the same outputs, grouping smolts tagged with predator tags with smolts tagged without the additional sensors but showing similar movements. A mammalian predator was identified as the cause of most reversal movement, and hatchery-reared ranched smolts were found to be more likely predated upon by this predator than wild smolts within the lake and the estuary. However, overall migration success estimates were similar for both wild and hatchery-reared ranched fish. This study highlights the value of predator tags as an essential tool in the overall validation of detection data.
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Affiliation(s)
- C Waters
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - D Cotter
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - R O'Neill
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - A Drumm
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - J Cooney
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - N Bond
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
| | - G Rogan
- Marine Institute, Furnace, Newport, Co Mayo, Ireland
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4
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Glover RS, Stephen A. A novel automatic release cage increases survival of Atlantic salmon (Salmo salar) smolts released at night. JOURNAL OF FISH BIOLOGY 2023; 103:1560-1564. [PMID: 37650427 DOI: 10.1111/jfb.15547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/28/2023] [Accepted: 08/28/2023] [Indexed: 09/01/2023]
Abstract
Trap-and-transport of migratory fish is commonly used to bypass in-river obstructions. On the River Conon in Scotland, Atlantic salmon (Salmo salar) smolts are transported around two hydropower facilities. Smolt release occurs during daylight, when predation rates can be high. A novel automatic release cage (ARC) was designed to release smolts at night. Smolts were fitted with acoustic tags (n = 99) to compare survival. High post-release mortality was identified in the day-release group, with night-release survival >40% higher. ARCs can provide fishery managers with a cost-effective and reliable method of improving smolt survival.
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Kennedy R, Rosell R, Hunter E, Del Villar-Guerra D. Programmed acoustic tags reveal novel information on late-phase marine life in Atlantic salmon, Salmo salar. JOURNAL OF FISH BIOLOGY 2023; 102:707-711. [PMID: 36562572 DOI: 10.1111/jfb.15292] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
This pilot study used programmed acoustic tags implanted into Salmo salar smolts, in conjunction with an extensive offshore marine receiver array, to investigate late-stage migratory behaviour and survival of returning adult salmon. A total of 100 smolts were tagged in 2020, and a number of individuals were successfully detected as returning adults in 2021. After detection efficiency was accounted for, 5-9 adults were estimated to have returned to the offshore array c. 45 km from the river mouth. A total of three fish were subsequently detected in the river. Losses of between 40% and 66% were evident during the final stages of ocean migration, and one tagged fish provided direct evidence of a predation event.
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Affiliation(s)
- Richard Kennedy
- Agri-Food & Biosciences Institute, River Bush Salmon Station, Bushmills, UK
- Agri-Food & Biosciences Institute, Belfast, UK
| | | | - Ewan Hunter
- Agri-Food & Biosciences Institute, Belfast, UK
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6
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Lennox RJ, Dahlmo LS, Ford AT, Sortland LK, Vogel EF, Vollset KW. Predation research with electronic tagging. WILDLIFE BIOLOGY 2022. [DOI: 10.1002/wlb3.01045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Robert J. Lennox
- Norwegian Inst. for Nature Research Trondheim Norway
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
| | - Lotte S. Dahlmo
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
- Dept of Biological Sciences, Univ. of Bergen Bergen Norway
| | - Adam T. Ford
- Univ. of British Columbia Okanagan Kelowna BC Canada
| | - Lene K. Sortland
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
- Dept of Biological Sciences, Univ. of Bergen Bergen Norway
| | - Emma F. Vogel
- UiT − The Arctic Univ. of Norway, Faculty of Biosciences, Fisheries and Economics Tromsø Norway
| | - Knut Wiik Vollset
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
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7
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Yamada T, Urabe H, Nakamura F. Diel migration pattern of pink salmon fry in small streams. JOURNAL OF FISH BIOLOGY 2022; 100:1088-1092. [PMID: 35129835 DOI: 10.1111/jfb.15007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Downstream migration is a critical stage in the anadromous salmonid life cycle, but previous studies have shown different results between rivers or surveys for the diel downstream migration pattern of the fry of the pink salmon Oncorhynchus gorbuscha. We investigated the diel migration pattern of pink salmon fry in three small streams. Our results showed that pink salmon fry migrate mainly within a few hours after sunset; 89.9% of migration occurred between 18:00 and 23:00. Therefore, the results indicated that sunset time influences the diel migration pattern of pink salmon fry in small streams. This pattern could be a predator-avoidance behaviour.
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Affiliation(s)
- Taihei Yamada
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hirokazu Urabe
- Salmon and Freshwater Fisheries Research Institute, Hokkaido Research Organization, Eniwa, Japan
| | - Futoshi Nakamura
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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8
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Kennedy RJ, Rosell R, Allen M. Investigating the phenology of juvenile potamodromous brown trout (Salmo trutta L.) in two large lake catchments. JOURNAL OF FISH BIOLOGY 2022; 100:697-704. [PMID: 34932222 DOI: 10.1111/jfb.14982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/08/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
There is growing interest in the phenology of juvenile Salmo trutta and evidence of significant downstream migration during the autumn in some anadromous populations. The present study used acoustic telemetry to examine the phenology of potamodromous trout parr across a region encompassing two large lake catchments. One hundred sixty-seven trout parr were tagged in late summer across four lake tributaries between 2018 and 2020. In total, 75 tagged parr migrated into the lakes with 67 (89%) migrating between September and December and 8 (11%) migrating between March and June. Autumn migration was highly prevalent across all the tributaries, with 16%-66% of each tagged sample exhibiting autumn migration, and 0%-15% of each tagged sample exhibiting spring migration. Autumn migrants were significantly longer and heavier than spring migrants, but condition factor was similar. Autumn migrants were associated with higher river discharge levels and lower water temperatures than spring migrants. The management challenges posed by extensive autumn migration behaviour in migratory trout stocks are examined and discussed.
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Affiliation(s)
- Richard J Kennedy
- Agri-Food & Biosciences Institute, River Bush Salmon Station, Bushmills, UK
| | - Robert Rosell
- Agri-Food & Biosciences Institute, Newforge Lane, Belfast, UK
| | - Michelle Allen
- Agri-Food & Biosciences Institute, Newforge Lane, Belfast, UK
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9
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Tamario C, Degerman E, Polic D, Tibblin P, Forsman A. Size, connectivity and edge effects of stream habitats explain spatio-temporal variation in brown trout ( Salmo trutta) density. Proc Biol Sci 2021; 288:20211255. [PMID: 34666525 PMCID: PMC8527210 DOI: 10.1098/rspb.2021.1255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/28/2021] [Indexed: 01/18/2023] Open
Abstract
Ecological theory postulates that the size and isolation of habitat patches impact the colonization/extinction dynamics that determine community species richness and population persistence. Given the key role of lotic habitats for life-history completion in rheophilic fish, evaluating how the distribution of swift-flowing habitats affects the abundance and dynamics of subpopulations is essential. Using extensive electrofishing data, we show that merging island biogeography with meta-population theory, where lotic habitats are considered as islands in a lentic matrix, can explain spatio-temporal variation in occurrence and density of brown trout (Salmo trutta). Subpopulations in larger and less isolated lotic habitat patches had higher average densities and smaller between-year density fluctuations. Larger lotic habitat patches also had a lower predicted risk of excessive zero-catches, indicative of lower extinction risk. Trout density further increased with distance from the edge of adjacent lentic habitats with predator (Esox lucius) presence, suggesting that edge- and matrix-related mortality contributes to the observed patterns. These results can inform the prioritization of sites for habitat restoration, dam removal and reintroduction by highlighting the role of suitable habitat size and connectivity in population abundance and stability for riverine fish populations.
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Affiliation(s)
- Carl Tamario
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, 392 31 Kalmar, Sweden
| | - Erik Degerman
- Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences, Drottningholm, Sweden
| | - Daniela Polic
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, 392 31 Kalmar, Sweden
| | - Petter Tibblin
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, 392 31 Kalmar, Sweden
| | - Anders Forsman
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, 392 31 Kalmar, Sweden
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10
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Spawning-related movements in a salmonid appear timed to reduce exposure to visually oriented predators. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Kennedy RJ, Campbell W, Gallagher K, Evans D. River lamprey present an unusual predation threat to Atlantic salmon smolts in Lough Neagh, Northern Ireland. JOURNAL OF FISH BIOLOGY 2020; 97:1265-1267. [PMID: 32725628 DOI: 10.1111/jfb.14477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/21/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Abstract
A new monitoring programme on the Lough Neagh catchment has documented a high incidence of river lamprey, Lampetra fluviatilis L., predation on Atlantic salmon smolts, Salmo salar L. In total 470 smolts were examined during the 2020 emigration period with 168 fish (36%) exhibiting lamprey scars of which 57 were lightly scarred and 111 were classed as heavily scarred. Lamprey predation was not size selective on Lough Neagh S. salar smolts.
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Affiliation(s)
- Richard J Kennedy
- Agri-Food & Biosciences Institute, River Bush Salmon Station, Bushmills, UK
| | - Warren Campbell
- Department of Agriculture, Environment and Rural Affairs, Belfast, UK
| | | | - Derek Evans
- Agri-Food & Biosciences Institute, Belfast, UK
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12
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Lennox RJ, Salvanes AGV, Barlaup BT, Stöger E, Madhun A, Helle TM, Vollset KW. Negative impacts of the sea lice prophylactic emamectin benzoate on the survival of hatchery released salmon smolts in rivers. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 224:105519. [PMID: 32502848 DOI: 10.1016/j.aquatox.2020.105519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/07/2020] [Accepted: 05/10/2020] [Indexed: 06/11/2023]
Abstract
Emamectin benzoate (EB) is a prophylactic pharmaceutical used to protect Atlantic salmon (Salmo salar) smolts migrating out of rivers and into the ocean against sea lice parasites. Randomized control trials comparing the marine survival of smolts treated with EB to a control group is used to calculate the fraction of marine mortality attributable to sea lice parasitism. However, it is assumed that there is no baseline difference in survival induced by the application of EB treatment. We used a combined laboratory and field study approach to investigate the potential impacts of EB treatment on behaviour and survival of hatchery-reared Atlantic salmon in western Norway. In aquaria experiments, EB-treated salmon smolts did not differ significantly in exploratory behaviour. Fish from treated groups responded similarly to simulated predator attack with spontaneous escape and elevated gill beat rate. Three rivers in the Osterfjord system of western Norway were selected for field experiments, Dale, Vosso, and Modalen. Dale River smolts were treated with intraperitoneal EB injections and had lower probability of detection in a wolf trap downstream of the release site than control smolts. Salmon smolts raised in the Vosso River hatchery were treated with EB delivered in their food and were detected on PIT antennas at the rivermouth of Vosso and Modalen at lower rates than control fish, but only when released at downstream sites. Calculation of risk ratios suggested that the bias in mortality caused by treatment with EB decreased the estimated survival of treated fish from an expected 18%to 46%, reducing the observable negative impact of sea lice on Atlantic salmon smolts in randomized control trials. The results suggest that estimates of the fraction of mortality attributable to sea lice may be underestimated due to lower baseline survival of treated fish caused by treatment and bring urgent attention towards a potential systematic underestimation of the impacts of sea lice on wild salmon.
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Affiliation(s)
- Robert J Lennox
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries (LFI), Nygårdsporten 112, 5008 Bergen, Norway.
| | | | - Bjørn T Barlaup
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries (LFI), Nygårdsporten 112, 5008 Bergen, Norway
| | - Elisabeth Stöger
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries (LFI), Nygårdsporten 112, 5008 Bergen, Norway
| | | | - Turid M Helle
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries (LFI), Nygårdsporten 112, 5008 Bergen, Norway
| | - Knut Wiik Vollset
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries (LFI), Nygårdsporten 112, 5008 Bergen, Norway
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13
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Ferguson A, Reed TE, Cross TF, McGinnity P, Prodöhl PA. Anadromy, potamodromy and residency in brown trout Salmo trutta: the role of genes and the environment. JOURNAL OF FISH BIOLOGY 2019; 95:692-718. [PMID: 31197849 PMCID: PMC6771713 DOI: 10.1111/jfb.14005] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/09/2019] [Indexed: 05/10/2023]
Abstract
Brown trout Salmo trutta is endemic to Europe, western Asia and north-western Africa; it is a prominent member of freshwater and coastal marine fish faunas. The species shows two resident (river-resident, lake-resident) and three main facultative migratory life histories (downstream-upstream within a river system, fluvial-adfluvial potamodromous; to and from a lake, lacustrine-adfluvial (inlet) or allacustrine (outlet) potamodromous; to and from the sea, anadromous). River-residency v. migration is a balance between enhanced feeding and thus growth advantages of migration to a particular habitat v. the costs of potentially greater mortality and energy expenditure. Fluvial-adfluvial migration usually has less feeding improvement, but less mortality risk, than lacustrine-adfluvial or allacustrine and anadromous, but the latter vary among catchments as to which is favoured. Indirect evidence suggests that around 50% of the variability in S. trutta migration v. residency, among individuals within a population, is due to genetic variance. This dichotomous decision can best be explained by the threshold-trait model of quantitative genetics. Thus, an individual's physiological condition (e.g., energy status) as regulated by environmental factors, genes and non-genetic parental effects, acts as the cue. The magnitude of this cue relative to a genetically predetermined individual threshold, governs whether it will migrate or sexually mature as a river-resident. This decision threshold occurs early in life and, if the choice is to migrate, a second threshold probably follows determining the age and timing of migration. Migration destination (mainstem river, lake, or sea) also appears to be genetically programmed. Decisions to migrate and ultimate destination result in a number of subsequent consequential changes such as parr-smolt transformation, sexual maturity and return migration. Strong associations with one or a few genes have been found for most aspects of the migratory syndrome and indirect evidence supports genetic involvement in all parts. Thus, migratory and resident life histories potentially evolve as a result of natural and anthropogenic environmental changes, which alter relative survival and reproduction. Knowledge of genetic determinants of the various components of migration in S. trutta lags substantially behind that of Oncorhynchus mykiss and other salmonines. Identification of genetic markers linked to migration components and especially to the migration-residency decision, is a prerequisite for facilitating detailed empirical studies. In order to predict effectively, through modelling, the effects of environmental changes, quantification of the relative fitness of different migratory traits and of their heritabilities, across a range of environmental conditions, is also urgently required in the face of the increasing pace of such changes.
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Affiliation(s)
- Andrew Ferguson
- School of Biological SciencesQueen's University BelfastBelfastUK
| | - Thomas E. Reed
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Tom F. Cross
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Philip McGinnity
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Paulo A. Prodöhl
- School of Biological SciencesQueen's University BelfastBelfastUK
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