Morphometrics, body condition, and growth of the ringed seal (<i>Pusa hispida saimensis</i>) in Lake Saimaa: Implications for conservation

Auttila, Miina; Kurkilahti, Mika; Niemi, Marja; Levänen, Riikka; Sipilä, Tero; Isomursu, Marja; Koskela, Jouni; Kunnasranta, Mervi

doi:10.1111/mms.12256

Cited by 11 publications

(6 citation statements)

References 59 publications

(84 reference statements)

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“…data). The Saimaa ringed seal's asymptomatic body mass is reported to be 59 kg (55.8-62.4, n = 113), which is similar to that of medium sized marine ringed seals (Auttila et al 2016).…”

Section: Introductionmentioning

confidence: 72%

Muscles of Mastication and the Temporo-Mandibular Joint of the Saimaa (Pusa hispida saimensis) and Baltic (Pusa hispida botnica) Ringed Seals

Laakkonen

Jernvall

2020

Annales Zoologici Fennici

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As part of our research aiming to understand the morphological variation in ringed seals, we dissected mastication muscles of nine Saimaa ringed seals and two Baltic ringed seals. We found no significant differences in the muscles of mastication between these subspecies but the location of the tympanic bulla in relation to the articular surface of the temporomandibular joint was more medial in the Saimaa ringed seal. As compared with the previously studied Baikal and Caspian seals, the origin of the jaw-opening digastricus muscle covered less of the tympanic bulla in the Saimaa and Baltic ringed seals. Our data on masticatory-muscle masses indicated that similarly to terrestrial mammal species, the growth patterns of mastication muscles of the Saimaa ringed seal differed from each other according to the body size.

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“…data). The Saimaa ringed seal's asymptomatic body mass is reported to be 59 kg (55.8-62.4, n = 113), which is similar to that of medium sized marine ringed seals (Auttila et al 2016).…”

Section: Introductionmentioning

confidence: 72%

Muscles of Mastication and the Temporo-Mandibular Joint of the Saimaa (Pusa hispida saimensis) and Baltic (Pusa hispida botnica) Ringed Seals

Laakkonen

Jernvall

2020

Annales Zoologici Fennici

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“…The seals studied during each tracking period ( n = 25) were categorized as subadults ( n = 3, body length <100 cm and mass <40 kg) and adults ( n = 22, Table 1). Ringed seals lose weight during the spring due to reproductive and molting activities [33, 43], and the length measurements of living individuals in field conditions are often inaccurate. Therefore, other age measurement criteria, such as known breeding or the earlier identified as an adult verified by photo-identification data [44], were also used for some of the smaller individuals, which were consequently classified as adults, although their lengths or weights did not fully fit the adult seal criteria [33].…”

Section: Methodsmentioning

confidence: 99%

“…The ringed seal is one of the northern seals most vulnerable to the declines in the extent or quality of ice and snow cover [26–29]. Premature ice break-up and early lair collapse leave pups subject to increased predation, human disturbances and exposure to extreme weather conditions [30–33]. Climate change has negative effects in the endangered Saimaa ringed seal population, especially on juvenile survival [34, 35], which is already weakened due to incidental by-catch mortality [36–38].…”

Section: Introductionmentioning

confidence: 99%

Winter behavior of Saimaa ringed seals: Non-overlapping core areas as indicators of avoidance in breeding females

Niemi¹,

Liukkonen²,

Koivuniemi³

et al. 2019

PLoS ONE

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Climate change, together with increasing human activity, poses a threat to the breeding success of endangered landlocked ringed seals (Phoca hispida saimensis). In this study, we estimated the spatial ecology of Saimaa ringed seals during the breeding season in the ice-covered period of December-April. The telemetry data on tagged seals (n = 20), with a total of 25 separate tracking periods and birth lair locations (n = 59) of non-tagged seals, were studied to estimate the movement ecology and breeding density. The movements of the ringed seals were more restricted during the ice-covered season; the total home range size (average 7.4 km2) in winter was 13 times smaller than that in summer. Individual tagged seals occupied an average of 5 ± 3 SD subnivean haul outs (snow lairs or ice cavities), and the mean distance between the haul outs was 1.6 ± 1.1 SD km (range 0.2–5.9 km). Moreover, our data indicated that ringed seal females likely exhibited breeding time avoidance of each other’s core areas, which may indicate some degree of territoriality. This was supported by the findings that the core areas (mean 1.2 km2) of tagged adult females (n = 9), did not overlap with each other. Also data on non-tagged seals showed that females did not give birth to pups within the core area radius of other parturient females. This study, together with earlier findings on the home ranges of nursed pups and perinatal mortality rates, has implications into land usage planning in Lake Saimaa by highlighting the need of undisturbed area between seal lairs and anthropogenic disturbances.

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“…Differences between sexes for L 0 , L ∞ , k and Age 95%L ∞ were estimated from the models above by replacing L ∞ with (L ∞ female + (L ∞ difference × sex)) where sex was a class variable. Nonlinear model fitting was done with SAS 9.4 (PROC NLIN and PROC NLMIXED) and is described in more detail in Auttila et al (2016).…”

Section: Statistical Testsmentioning

confidence: 99%

Delayed effects of prey fish quality and winter temperature during the birth year on adult size and reproductive rate of Baltic grey seals

Kauhala

Kurkilahti

2019

Mamm Res

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Environmental conditions of mammalian juveniles may have delayed effects on their life histories and fitness, such as body size or reproductive rate later in their lives. In the present study, we tested this hypothesis on Baltic grey seals (Halichoerus grypus) and examined (1) the possible effects of prey fish quality and winter temperature on body condition of grey seal pups of both sexes and (2) the possible delayed impacts of pup environment on the body size and birth rate of adult grey seals. Body condition (blubber thickness) of especially female pups in April–May correlated negatively with winter temperatures, and body condition of male pups correlated positively with prey fish quality (herring Clupea harengus and sprat Sprattus sprattus weight). Males reached the asymptotic length at the age of 10.3 years, and body length of adult males (≥ 10 years old) was positively related to herring and sprat weight in their birth year. Females reached the asymptotic length at the age of 5.9 years. Birth rate of females (age 7–24 years) was negatively related to winter temperature in their birth year. We conclude that both changes in prey fish quality and climate may affect body condition of pups and thus also cause delayed effects on adult fitness: body size and reproductive rate of Baltic grey seals.

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Morphometrics, body condition, and growth of the ringed seal (Pusa hispida saimensis) in Lake Saimaa: Implications for conservation

Cited by 11 publications

References 59 publications

Muscles of Mastication and the Temporo-Mandibular Joint of the Saimaa (Pusa hispida saimensis) and Baltic (Pusa hispida botnica) Ringed Seals

Muscles of Mastication and the Temporo-Mandibular Joint of the Saimaa (Pusa hispida saimensis) and Baltic (Pusa hispida botnica) Ringed Seals

Winter behavior of Saimaa ringed seals: Non-overlapping core areas as indicators of avoidance in breeding females

Delayed effects of prey fish quality and winter temperature during the birth year on adult size and reproductive rate of Baltic grey seals

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