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Nowak BVR, Bowen WD, den Heyer CE, Lang SLC, Lidgard DC. Ontogeny of movement patterns in naïve grey seal pups inhabiting a complex continental shelf ecosystem. PLoS One 2023; 18:e0290707. [PMID: 37756252 PMCID: PMC10529606 DOI: 10.1371/journal.pone.0290707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 08/14/2023] [Indexed: 09/29/2023] Open
Abstract
Most vertebrate offspring must transition from the relative security of parental care (nutrition and protection) to independent foraging. Offspring face many challenges during this critical period, particularly in species where parental care ends at weaning, such as the grey seal (Halichoerus grypus). We studied the development of movement behaviour in naïve grey seal pups from their first trips to sea to about five months of age. Twenty-five (12 males and 13 females) newly-weaned pups were fitted with satellite-linked GPS tags on Sable Island, Nova Scotia, Canada in January 2016. The influence of fixed effects (pup size, sex, week) and the random effect of pup identity on trip characteristics were examined. Movement behaviour was analyzed using a move persistence mixed-effects model. Habitat use was highly variable among individuals and covered much of the geographic distribution of the population. Unlike older juveniles, subadults, and adults in this population, most naïve pups used multiple haulout sites to begin and end trips. There was little evidence of area-restricted search behaviour during trips, suggesting that naïve pups were using an opportunistic foraging tactic that may result in more variable foraging success than that of older, experienced animals. Naïve pups made longer trips with longer haulout durations between them than observed for older greys seals. Males and females differed in some trip characteristics, but sex effects were small over the first few months of life. Offspring size at weaning was not a useful predictor of trip characteristics. Move persistence of grey seal pups was initially high and then decreased over time as individuals gained experience. Both intrinsic and extrinsic factors were influential on the movements of grey seal pups. Greater body length at weaning, longer duration spent on shore after weaning, shallower water column depth, and farther distance from shore were all associated with lower move persistence. Female grey seal pups had lower move persistence than males. Overall, the movements of naïve grey seal pups during the first few months of life were characterized by extensive exploration, but move persistence decreased over time suggesting they may be using an exploration-refinement foraging tactic.
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Affiliation(s)
- Benia V. R. Nowak
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - W. Don Bowen
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Cornelia E. den Heyer
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Shelley L. C. Lang
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
- Northwest Atlantic Fisheries Centre, St. John’s, Newfoundland, Canada
| | - Damian C. Lidgard
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Individual Quality Drives Life History Variation in a Long-Lived Marine Predator. Am Nat 2023; 202:351-367. [PMID: 37606942 DOI: 10.1086/725451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
AbstractIndividual quality and environmental conditions may mask or interact with energetic trade-offs in life history evolution. Deconstructing these sources of variation is especially difficult in long-lived species that are rarely observed on timescales long enough to disentangle these effects. Here, we investigated relative support for variation in female quality and costs of reproduction as factors shaping differences in life history trajectories using a 32-year dataset of repeated reproductive measurements from 273 marked, known-age female gray seals (Halichoerus grypus). We defined individual reproductive investment using two traits, reproductive frequency (a female's probability of breeding) and provisioning performance (offspring weaning mass). Fitted hierarchical Bayesian models identified individual investment relative to conspecifics (over a female's entire life and in three age classes) and subsequently estimated how these investment metrics and the Atlantic Multidecadal Oscillation are associated with longevity. Individual differences (i.e., quality) contributed a large portion of the variance in reproductive traits. Females that consistently invest well in their offspring relative to other females survive longer. The best-supported model estimated survival as a function of age class-specific provisioning performance, where late-life performance was particularly variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. Overall, these results suggest that in gray seals, individual quality is a stronger driver in life history variation than individual strategies resulting from energetic trade-offs.
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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Large offspring have enhanced lifetime reproductive success: Long-term carry-over effects of weaning size in gray seals ( Halichoerus grypus). Ecol Evol 2023; 13:e10095. [PMID: 37293121 PMCID: PMC10244896 DOI: 10.1002/ece3.10095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 06/10/2023] Open
Abstract
An individual's size in early stages of life may be an important source of individual variation in lifetime reproductive performance, as size effects on ontogenetic development can have cascading physiological and behavioral consequences throughout life. Here, we explored how size-at-young influences subsequent reproductive performance in gray seals (Halichoerus grypus) using repeated encounter and reproductive data on a marked sample of 363 females that were measured for length after weaning, at ~4 weeks of age, and eventually recruited to the Sable Island breeding colony. Two reproductive traits were considered: provisioning performance (mass of weaned offspring), modeled using linear mixed effects models; and reproductive frequency (rate at which a female returns to breed), modeled using mixed effects multistate mark-recapture models. Mothers with the longest weaning lengths produced pups 8 kg heavier and were 20% more likely to breed in a given year than mothers with the shortest lengths. Correlation in body lengths between weaning and adult life stages, however, is weak: Longer pups do not grow to be longer than average adults. Thus, covariation between weaning length and future reproductive performance appears to be a carry-over effect, where the size advantages afforded in early juvenile stages may allow enhanced long-term performance in adulthood.
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Affiliation(s)
- Janelle J. Badger
- Department of Biology and WildlifeUniversity of Alaska FairbanksFairbanksAlaskaUSA
- Present address:
Pacific Islands Fisheries Science CenterNational Oceanic and Atmospheric AdministrationHonoluluHawaiiUSA
| | - W. Don Bowen
- Department of Fisheries and Oceans CanadaBedford Institute of OceanographyDartmouthNova ScotiaCanada
| | - Cornelia E. den Heyer
- Department of Fisheries and Oceans CanadaBedford Institute of OceanographyDartmouthNova ScotiaCanada
| | - Greg A. Breed
- Department of Biology and WildlifeUniversity of Alaska FairbanksFairbanksAlaskaUSA
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAlaskaUSA
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Bubac CM, Cullingham CI, Fox JA, Bowen WD, den Heyer CE, Coltman DW. Genetic association with boldness and maternal performance in a free-ranging population of grey seals (Halichoerus grypus). Heredity (Edinb) 2021; 127:35-51. [PMID: 33927365 PMCID: PMC8249389 DOI: 10.1038/s41437-021-00439-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 02/03/2023] Open
Abstract
Individual variation in quantitative traits clearly influence many ecological and evolutionary processes. Moderate to high heritability estimates of personality and life-history traits suggest some level of genetic control over these traits. Yet, we know very little of the underlying genetic architecture of phenotypic variation in the wild. In this study, we used a candidate gene approach to investigate the association of genetic variants with repeated measures of boldness and maternal performance traits (weaning mass and lactation duration) collected over an 11- and 28-year period, respectively, in a free-ranging population of grey seals on Sable Island National Park Reserve, Canada. We isolated and re-sequenced five genes: dopamine receptor D4 (DRD4), serotonin transporter (SERT), oxytocin receptor (OXTR), and melanocortin receptors 1 (MC1R) and 5 (MC5R). We discovered single nucleotide polymorphisms (SNPs) in each gene; and, after accounting for loci in linkage disequilibrium and filtering due to missing data, we were able to test for genotype-phenotype relationships at seven loci in three genes (DRD4, SERT, and MC1R). We tested for association between these loci and traits of 180 females having extreme shy-bold phenotypes using mixed-effects models. One locus within SERT was significantly associated with boldness (effect size = 0.189) and a second locus within DRD4 with weaning mass (effect size = 0.232). Altogether, genotypes explained 6.52-13.66% of total trait variation. Our study substantiates SERT and DRD4 as important determinants of behaviour, and provides unique insight into the molecular mechanisms underlying maternal performance variation in a marine predator.
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Affiliation(s)
- Christine M. Bubac
- grid.17089.37Department of Biological Sciences, University of Alberta, Edmonton, AB Canada
| | - Catherine I. Cullingham
- grid.34428.390000 0004 1936 893XDepartment of Biology, Carleton University, Ottawa, ON Canada
| | - Janay A. Fox
- grid.17089.37Department of Biological Sciences, University of Alberta, Edmonton, AB Canada ,grid.14709.3b0000 0004 1936 8649Redpath Museum and Department of Biology, McGill University, Montreal, QC Canada
| | - W. Don Bowen
- grid.418256.c0000 0001 2173 5688Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, NS Canada ,grid.55602.340000 0004 1936 8200Biology Department, Dalhousie University, Halifax, NS Canada
| | - Cornelia E. den Heyer
- grid.418256.c0000 0001 2173 5688Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, NS Canada
| | - David W. Coltman
- grid.17089.37Department of Biological Sciences, University of Alberta, Edmonton, AB Canada
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Bowen WD, den Heyer CE, Lang SLC, Lidgard D, Iverson SJ. Exploring causal components of plasticity in grey seal birthdates: Effects of intrinsic traits, demography, and climate. Ecol Evol 2020; 10:11507-11522. [PMID: 33144980 PMCID: PMC7593198 DOI: 10.1002/ece3.6787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/22/2020] [Accepted: 07/28/2020] [Indexed: 11/08/2022] Open
Abstract
Change in breeding phenology is often a response to environmental forcing, but less is known of the mechanism underlying such changes and their fitness consequences. Here, we report on changes in the breeding phenology from a 27-year longitudinal study (1991-2017) of individually marked, known-aged grey seals (Halichoerus grypus) on Sable Island, Nova Scotia, Canada. We used generalized linear mixed models and a 3-step process to develop a model that includes interactions between intrinsic and extrinsic covariates and to test hypotheses about the influence of fixed factors (maternal age, parity, previous reproductive success, pup sex, colony density, Atlantic Multidecal Oscillation (AMO), North Atlantic Oscillation (NAO), and Sea Surface Temperature) and a random factor (female identity) on parturition dates. We also examined the consequences of the shift in birthdates on maternal energy allocation in offspring as measured by pup weaning mass. Birthdates were known for 2,768 pups of 660 known-age females. For 494 females with ≥2 parturition dates, repeatability as measured by the intraclass correlation was high (mean = 0.66). 87% of the variation in birthdates was explained by a mixed-effects model that included intrinsic and extrinsic fixed effects. Most of the explained variation was associated with the random effect of female identity. Parity was the most important intrinsic fixed effect, with inexperienced mothers giving birth later in the season than multiparous females. Over almost 3 decades, mean birthdates advanced by 15 days. The mixed model with intrinsic effects and population size, the detrended AMO from the previous year and mean NAO in the previous 3 years explained 80% of the variation with 21% of variation from the fixed effects. Both primiparous and multiparous individuals responded to the climate forcing, and there was strong evidence for heterogeneity in the response. Nevertheless, the shift in birthdates did not impact pup weaning mass.
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Affiliation(s)
- William Don Bowen
- Population Ecology DivisionBedford Institute of OceanographyDartmouthNSCanada
- Department of BiologyDalhousie UniversityHalifaxNSCanada
| | | | - Shelley L. C. Lang
- Population Ecology DivisionBedford Institute of OceanographyDartmouthNSCanada
- Department of BiologyDalhousie UniversityHalifaxNSCanada
| | - Damian Lidgard
- Department of BiologyDalhousie UniversityHalifaxNSCanada
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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Variation in individual reproductive performance amplified with population size in a long‐lived carnivore. Ecology 2020; 101:e03024. [DOI: 10.1002/ecy.3024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/12/2019] [Accepted: 01/22/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Janelle J. Badger
- Department of Biolog y and Wildlife University of Alaska Fairbanks Fairbanks Alaska756100 USA
| | - W. Don Bowen
- Department of Fisheries and Oceans Canada Bedford Institute of Oceanography 1 Challenger Dr Dartmouth Nova Scotia Canada
| | - Cornelia E. den Heyer
- Department of Fisheries and Oceans Canada Bedford Institute of Oceanography 1 Challenger Dr Dartmouth Nova Scotia Canada
| | - Greg A. Breed
- Department of Biolog y and Wildlife University of Alaska Fairbanks Fairbanks Alaska756100 USA
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska757000 USA
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Hurley I, Wringe BF, den Heyer CE, Shackell NL, Lotze HK. Spatiotemporal bycatch analysis of the Atlantic halibut (
Hippoglossus hippoglossus
) longline fishery survey indicates hotspots for species of conservation concern. Conservation Science and Practice 2019. [DOI: 10.1111/csp2.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Isabelle Hurley
- Biology DepartmentDalhousie University Halifax Nova Scotia Canada
| | - Brendan F. Wringe
- Bedford Institute of OceanographyFisheries and Oceans Canada Dartmouth Nova Scotia Canada
| | - Cornelia E. den Heyer
- Bedford Institute of OceanographyFisheries and Oceans Canada Dartmouth Nova Scotia Canada
| | - Nancy L. Shackell
- Bedford Institute of OceanographyFisheries and Oceans Canada Dartmouth Nova Scotia Canada
| | - Heike K. Lotze
- Biology DepartmentDalhousie University Halifax Nova Scotia Canada
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Hurley I, Wringe BF, den Heyer CE, Shackell NL, Lotze HK. Spatiotemporal bycatch analysis of the Atlantic halibut ( Hippoglossus hippoglossus
) longline fishery survey indicates hotspots for species of conservation concern. Conservation Science and Practice 2019. [DOI: 10.1002/csp2.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Isabelle Hurley
- Biology Department; Dalhousie University; Halifax Nova Scotia Canada
| | - Brendan F. Wringe
- Bedford Institute of Oceanography; Fisheries and Oceans Canada; Dartmouth Nova Scotia Canada
| | - Cornelia E. den Heyer
- Bedford Institute of Oceanography; Fisheries and Oceans Canada; Dartmouth Nova Scotia Canada
| | - Nancy L. Shackell
- Bedford Institute of Oceanography; Fisheries and Oceans Canada; Dartmouth Nova Scotia Canada
| | - Heike K. Lotze
- Biology Department; Dalhousie University; Halifax Nova Scotia Canada
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Boudreau SA, Shackell NL, Carson S, den Heyer CE. Connectivity, persistence, and loss of high abundance areas of a recovering marine fish population in the Northwest Atlantic Ocean. Ecol Evol 2017; 7:9739-9749. [PMID: 29188005 PMCID: PMC5696389 DOI: 10.1002/ece3.3495] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/25/2017] [Accepted: 09/02/2017] [Indexed: 11/29/2022] Open
Abstract
In the early 1990s, the Northwest Atlantic Ocean underwent a fisheries‐driven ecosystem shift. Today, the iconic cod (Gadus morhua) remains at low levels, while Atlantic halibut (Hippoglossus hippoglossus) has been increasing since the mid‐2000s, concomitant with increasing interest from the fishing industry. Currently, our knowledge about halibut ecology is limited, and the lack of recovery in other collapsed groundfish populations has highlighted the danger of overfishing local concentrations. Here, we apply a Bayesian hierarchical spatiotemporal approach to model the spatial structure of juvenile Atlantic halibut over 36 years and three fisheries management regimes using three model parameters to characterize the resulting spatiotemporal abundance structure: persistence (similarity of spatial structure over time), connectivity (coherence of temporal pattern over space), and spatial variance (variation across the seascape). Two areas of high juvenile abundance persisted through three decades whereas two in the northeast are now diminished, despite the increased abundance and landings throughout the management units. The persistent areas overlap with full and seasonal area closures, which may act as refuges from fishing. Connectivity was estimated to be 250 km, an order of magnitude less than the distance assumed by the definition of the Canadian management units (~2,000 km). The underlying question of whether there are distinct populations within the southern stock unit cannot be answered with this model, but the smaller ~250 km scale of coherent temporal patterns suggests more complex population structure than previously thought, which should be taken into consideration by fishery management.
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Affiliation(s)
| | - Nancy L Shackell
- Bedford Institute of Oceanography Fisheries and Oceans Canada Dartmouth NS Canada
| | - Stuart Carson
- Department of Mathematics and Statistics Dalhousie University Halifax NS Canada
| | - Cornelia E den Heyer
- Bedford Institute of Oceanography Fisheries and Oceans Canada Dartmouth NS Canada
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Bowen WD, den Heyer CE, McMillan JI, Iverson SJ. Offspring size at weaning affects survival to recruitment and reproductive performance of primiparous gray seals. Ecol Evol 2015; 5:1412-24. [PMID: 25897381 PMCID: PMC4395171 DOI: 10.1002/ece3.1450] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 02/01/2015] [Accepted: 02/08/2015] [Indexed: 11/09/2022] Open
Abstract
Offspring size affects survival and subsequent reproduction in many organisms. However, studies of offspring size in large mammals are often limited to effects on juveniles because of the difficulty of following individuals to maturity. We used data from a long-term study of individually marked gray seals (Halichoerus grypus; Fabricius, 1791) to test the hypothesis that larger offspring have higher survival to recruitment and are larger and more successful primiparous mothers than smaller offspring. Between 1998 and 2002, 1182 newly weaned female pups were branded with unique permanent marks on Sable Island, Canada. Each year through 2012, all branded females returning to the breeding colony were identified in weekly censuses and a subset were captured and measured. Females that survived were significantly longer offspring than those not sighted, indicating size-selective mortality between weaning and recruitment. The probability of female survival to recruitment varied among cohorts and increased nonlinearly with body mass at weaning. Beyond 51.5 kg (mean population weaning mass) weaning mass did not influence the probability of survival. The probability of female survival to recruitment increased monotonically with body length at weaning. Body length at primiparity was positively related to her body length and mass at weaning. Three-day postpartum mass (proxy for birth mass) of firstborn pups was also positively related to body length of females when they were weaned. However, females that were longer or heavier when they were weaned did not wean heavier firstborn offspring.
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Affiliation(s)
- William D Bowen
- Bedford Institute of Oceanography Dartmouth, Nova Scotia, B2Y 4A2, Canada
| | | | - Jim I McMillan
- Bedford Institute of Oceanography Dartmouth, Nova Scotia, B2Y 4A2, Canada
| | - Sara J Iverson
- Department of Biology, Dalhousie University Halifax, Nova Scotia, B3H 4J1, Canada
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