Reconstructing climate–growth relations from the teeth of a marine mammal

Wittmann, Talia A.; Izzo, Christopher; Doubleday, Zoë A.; McKenzie, Jane; Delean, Steven; Gillanders, Bronwyn M.

doi:10.1007/s00227-016-2846-6

Cited by 12 publications

(15 citation statements)

References 53 publications

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“…No support was found for different foraging strategies between demographic groups; however, stable isotope values were related to ringed seal population productivity, with δ 13 C increasing at high lagged PWIs and δ 15 N increasing with percentage of pups in the subsistence harvest. During fasting, δ 13 C decreases due to the use of 13 C‐depleted lipids (Polischuk, Hobson, & Ramsay, 2001; Williams, Buck, Sears, & Kitaysky, 2007), and therefore, high δ 13 C may be related to increased body condition or growth in seals, which is indexed by PWI (Nguyen et al, 2017; Wittmann et al, 2016). Conversely, population body condition was not significantly related to δ 13 C or δ 15 N; however, the population body condition data from Harwood, Smith, Melling, et al (2012) focused only on the Amundsen Gulf.…”

Section: Discussionmentioning

confidence: 99%

“…We included a proportional width index (PWI), which is a measure of ringed seal teeth growth layers, from Nguyen et al (2017). PWIs are correlated with ringed seal productivity (Nguyen et al, 2017) and may represent a measure of somatic growth (Wittmann et al, 2016). Additionally, we included a lagged PWI variable from the previous annual period, to assess carryover effects.…”

Section: Methodsmentioning

confidence: 99%

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Spatial and temporal variability in ringed seal (Pusa hispida) stable isotopes in the Beaufort Sea

Boucher

Derocher

Richardson

2020

Ecology and Evolution

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Arctic ecosystem dynamics are shifting in response to warming temperatures and sea ice loss. Such ecosystems may be monitored by examining the diet of upper trophic level species, which varies with prey availability. To assess interannual variation in the Beaufort Sea ecosystem, we examined spatial and temporal trends in ringed seal (Pusa hispida) δ 13 C and δ 15 N in claw growth layers grown from 1964 to 2011. Stable isotopes were correlated with climate indices, environmental conditions, seal population productivity, and geographic location. Sex and age did not influence stable isotopes. Enriched 13 C was linked to cyclonic circulation regimes, seal productivity, and westward sampling locations. Higher δ 15 N was linked to lower sea surface temperatures, a higher percentage of pups in the subsistence harvest, and sample locations that were eastward and further from shore. From the 1960s to 2000s, ringed seal niche width expanded, suggesting a diversification of diet due to expansion of prey and/or seal space use. Overall, trends in ringed seal stable isotopes indicate changes within the Beaufort Sea ecosystem affected by water temperatures and circulation regimes. We suggest that continued monitoring of upper trophic level species will yield insights into changing ecosystem structure with climate change. K E Y W O R D SBeaufort Sea, climate change, niche width, Pusa hispida, ringed seal, stable isotopes | 4179 BOUCHER Et al.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Spatial and temporal variability in ringed seal (Pusa hispida) stable isotopes in the Beaufort Sea

Boucher

Derocher

Richardson

2020

Ecology and Evolution

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“…It is thought that the narrow adhesion line forms during periods of reduced growth (in most cases during winter or when there is reduced foraging, migration, hibernation, or environmental stressors), whereas the broader band forms during periods of rapid growth (when food resources are abundant or an animal is allocating more nutrients toward growth—Weinmann and Sicher 1947; Sissons 1949, 1971; Morris 1972; Klevezal 1996). The rate of GLG deposition can vary among species and individuals, as well as with environmental variables, sex, geographic region, life-history events, and various stressors (Scheffer and Peterson 1967; Harwood and Prime 1978; Klevezal and Myrick 1984; Manzanilla 1989; Boyd and Roberts 1993; Klevezal and Stewart 1994; Klevezal 1996; Hanson et al 2009; Medill et al 2010; Dellabianca et al 2011; Knox et al 2014; Wittmann et al 2016 and references therein; Hamilton et al 2017).…”

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confidence: 99%

Accuracy, precision, and error in age estimation of Florida manatees using growth layer groups in earbones

Lonati

Howell

Hostetler

et al. 2019

Journal of Mammalogy

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Ages of Florida manatees (Trichechus manatus latirostris) can be estimated by counting annual growth layer groups (GLGs) in the periotic dome portion of the tympanoperiotic complex of their earbones. The Florida Fish and Wildlife Conservation Commission manages an archive of more than 8,700 Florida manatee earbones collected from salvaged carcasses from 1989 to 2017. Our goal was to comprehensively evaluate techniques used to estimate age, given this large sample size and changes to processing protocols and earbone readers over time. We developed new standards for estimating ages from earbones, involving two independent readers to obtain measurements of within- and between-reader precision. To quantify accuracy, precision, and error, 111 earbones from manatees with approximately known ages (first known as calves: “KAC”) and 69 earbones from manatees with minimum known ages (“MKA,” based on photo-identification sighting histories) were processed, and their ages were estimated. There was greater precision within readers (coefficient of variation, CV: 2.4–8.5%) than between readers (CV: 13.1–13.3%). The median of age estimates fell within the true age range for 63.1% of KAC cases and was at least the sighting duration for 75.0% of MKA cases. Age estimates were generally unbiased, as indicated by an average raw error ± SD of −0.05 ± 3.05 years for the KAC group. The absolute error (i.e., absolute value of raw error) of the KAC data set averaged 1.75 ± 2.50 years. Accuracy decreased and error increased with increasing known age, especially for animals over 15 years old, whose ages were mostly underestimated due to increasing levels of resorption (the process of bone turnover that obscures GLGs). Understanding the degree of uncertainty in age estimates will help us assess the utility of age data in manatee population models. We emphasize the importance of standardizing and routinely reviewing age estimation and processing protocols to ensure that age data remain consistent and reliable.

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“…This is well-established in teleosts; with particular interest in climate change effects (Morrongiello et al, 2012). However, in top order predators such as sharks and marine mammals, there is little investigation of environmental controls on growth due to logistical constraints of controlled experimental studies and long-term observational work (Wittmann et al, 2016). Moreover, shifts in shark growth are primarily attributed to fishing effects (Walker et al, 1998), resulting in a paucity of information on the environmental correlates of growth in top order aquatic taxa.…”

Section: Introductionmentioning

confidence: 99%

“…Biochronologies provide a means of measuring growth deviations though time, using the incremental patterns of calcified structures as proxies of somatic growth (Morrongiello et al, 2012). For example, biochronologies of growth, based on tooth incremental patterns, have demonstrated growth-temperature relationships in New Zealand fur seals (Wittmann et al, 2016). Shark vertebrae, possess analogous incremental growth patterns and are widely used to estimate chronological age (Cailliet and Goldman, 2004), with vertebral increments potentially providing suitable proxies of somatic shark growth when allometry is validated.…”

Section: Introductionmentioning

confidence: 99%

Port Jackson Shark Growth Is Sensitive to Temperature Change

Izzo

Gillanders

2020

Front. Mar. Sci.

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Climatic effects on the growth of apex marine predators-such as sharks-are poorly understood; moreover, shifts in shark growth are primarily attributed to fishing pressure. This paucity of information impedes management and conservation planning for these taxa. Using vertebral increment patterning as a proxy of somatic growth, this study reconstructed mean growth of the philopatric and demersal Heterodontus portusjacksoni population from Gulf St Vincent (South Australia). A biochronology of shark growth spanning a 15 year period (1996-2010) was developed using mixed effects models. The biochronology showed considerable year-to-year deviations in growth that were significantly and negatively correlated with mean sea surface temperatures during the species' breeding season (July to November). These findings are consistent with mesocosm experiments and support the influence of changing climates on shark growth; particularly in an inshore, demersal, and highly philopatric shark species. It is likely that the effects of environmental variation occur in a speciesspecific manner, governed by life history strategies and ecological requirements. In this manner, life history traits might aid in estimating species vulnerability to climate change.

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Reconstructing climate–growth relations from the teeth of a marine mammal

Cited by 12 publications

References 53 publications

Spatial and temporal variability in ringed seal (Pusa hispida) stable isotopes in the Beaufort Sea

Spatial and temporal variability in ringed seal (Pusa hispida) stable isotopes in the Beaufort Sea

Accuracy, precision, and error in age estimation of Florida manatees using growth layer groups in earbones

Port Jackson Shark Growth Is Sensitive to Temperature Change

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