The diet of the Saimaa ringed seal Phoca hispida saimensis

Kunnasranta, Mervi; Hyvärinen, Heikki; Sipilä, Tero; Koskela, Jouni

doi:10.4098/at.arch.99-42

Cited by 22 publications

(23 citation statements)

References 17 publications

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“…We obtained samples of the potential prey species of the seals (Kunnasranta et al . ) collected by local fishermen from Lake Saimaa during the years 2010 and 2011. The carbon and nitrogen stable isotope values of these species were analyzed and used to form a reference database of prey species.…”

Section: Methodsmentioning

confidence: 99%

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Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)

Auttila

Sinisalo

Valtonen

et al. 2014

Marine Mammal Science

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Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis) Auttila, Miina; Sinisalo, Tuula; Valtonen, Mia; Niemi, Marja; Viljanen, Markku; Kurkilahti, Mika; Kunnasranta, Mervi Auttila, M., Sinisalo, T., Valtonen, M., Niemi, M., Viljanen, M., Kurkilahti, M., & Kunnasranta, M. (2015). Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis). Marine Mammal Science, 31 (1) AbstractThe Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d N values indicated that pups start to recover from postweaning stress and gain weight around the age of 6 mo. The isotope values differed regionally, which emphasizes that samples from consumers and prey should be collected from the same regions to improve interpretation of the stable isotopic results. Overall, diet composition suggests minimal to nonexistent competition with commercial or recreational fishing. However, observed weight loss of pups during summer may be related to higher risk of bycatch and this should be taken into account when planning temporal fishing closures.

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Section: Methodsmentioning

confidence: 99%

“…, ), only a few studies concerning the diet and foraging behavior of freshwater ringed seals have been conducted so far (Kunnasranta et al . , Sinisalo ).…”

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confidence: 99%

Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)

Auttila

Sinisalo

Valtonen

et al. 2014

Marine Mammal Science

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“…In addition, the vibrissae of the bearded seals have no beaded structure as do the vibrissae of the ringed seal. All of Comparison of Vibrissae of Aquatic and Terrestrial Mammals Brain Behav Evol 2009;74:268-279 277 these differences might be connected to the different life histories of the benthic foraging bearded seal and the ringed seal that mainly eats pelagic small fish and large crustaceans [e.g., McLaren, 1958;Kunnasranta et al, 1999].…”

Section: Discussionmentioning

confidence: 99%

Aquatic Environment and Differentiation of Vibrissae: Comparison of Sinus Hair Systems of Ringed Seal, Otter and Pole Cat

et al. 2009

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This study investigated the structure and innervation of the vibrissal systems of the pole cat (Mustela putorius), European otter (Lutra lutra) and ringed seal (Phoca hispida) in order to find adaptations to aquatic environment. The number of myelinated nerve fibers of deep vibrissal nerve (DVN) of the entire vibrissal system was considerably greater in the ringed seal (10×, aquatic mammal) and in the otter (4×, semi-aquatic mustelid) compared to the pole cat which is a terrestrial mustelid. Similarly, the number of neural end organs in the vibrissae of ringed seals was about ten times more numerous than in pole cats. The number of the vibrissae in the heads of otters was almost two times more than in pole cats, and all vibrissa groups had similar structures and innervation. The asymmetrically developed carpal vibrissae of otters were, however, more poorly innervated than the vibrissae of the head and had only smooth musculature. In the ringed seal the orientation of lanceolate end organs differed in different vibrissae, indicating the specialization of these vibrissae for different kinds of sensory functions. Ringed seal vibrissae contain structures which obviously are developed as adaptations to an aquatic environment. These include the modified mitochondria of Merkel cells, with Merkel cell-neurite complexes very often associated ciliated cells, liquid filled vesicles or intercellular spaces below the basal cell layer of the outer root sheath at the ring sinus level, a long upper cavernous sinus and a flattened beaded structure of the vibrissa hairs. As the vibrissae of aquatic mammals have analogous functions to the lateral line organ of fishes, we suggest using the term ‘vibrissal sense’ for the vibrissa system of aquatic mammals.

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“…One ringed seal consumes approximately 1,000 kg of fish annually [3]. Correspondingly, pike of the weight collected in our samples eat approximately 2.7 to 11 kg fish annually [31], although seasonal variation occurs in activity, feeding, lipids, and OCl concentrations in both fish and the ringed seal [3,35,41,44]. Third, as mentioned above, the metabolic capacities of these animals differ.…”

Section: Discussionmentioning

confidence: 93%

“…Chem. 21,2002 A. Kostamo et al the main prey species for the Saimaa seal, which typically feeds on fish smaller than 20 cm long [3]. These fish are also the main prey species for pike [30,31].…”

Section: Samplesmentioning

confidence: 99%

Organochlorine concentrations in the saimaa ringed seal (Phoca hispida saimensis) from Lake Haukivesi, Finland, 1981 to 2000, and in its diet today

Kostamo

Hyvärinen

Pellinen³

et al. 2002

Enviro Toxic and Chemistry

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Organochlorine and mercury (Hg) pollution has been one possible reason for a decline in the size of the population of the Saimaa ringed seal (Phoca hispida saimensis) in Lake Haukivesi, Finland. In this study, we analyzed changes in the concentrations of organochlorine compounds (OCls) and extractable organic halogen (EOX) in the blubber of Saimaa ringed seals that died from 1981 to 2000. In addition, the present concentrations and biomagnification factors of OCls and Hg from the main prey fish of ringed seal and pike (Esox lucius) were determined. Concentrations of pollutants in bream (Abramis brama) also were analyzed. The decline in the OCl concentrations in blubber was, on average, 25% during the two decades since polychlorinated biphenyls and DDT compounds were banned. Today, concentrations in blubber of Saimaa ringed seals are similar of those in ringed seals from the Arctic. Correspondingly in fish, the OCl and Hg concentrations were, on average, similar to those found in other studies on Finnish and Arctic areas. The low diet concentrations and metabolism of OCls also reflect the lower age correlation of OCls in the male ringed seals in the 1990s than in the 1980s. Biomagnification was considerably higher from fish to the ringed seal than from prey fish to pike because of higher feeding rate of ringed seals and differences in the metabolisms of these animals.

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The diet of the Saimaa ringed seal Phoca hispida saimensis

Cited by 22 publications

References 17 publications

Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)

Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)

Aquatic Environment and Differentiation of Vibrissae: Comparison of Sinus Hair Systems of Ringed Seal, Otter and Pole Cat

Organochlorine concentrations in the saimaa ringed seal (Phoca hispida saimensis) from Lake Haukivesi, Finland, 1981 to 2000, and in its diet today

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