Loss of biodiversity is a growing problem and hence conservation of species is becoming increasingly important. In this dissertation conservation issues related to the critically endangered European mink (Mustela lutreola) are examined in situ (in the wild) and ex situ (in captivity) on both an individual and community level. It also contains fundamental research as conservation contexts often allow for conclusions beyond applied biology. Individual behavioural differences, e.g. personality, can impact fitness and are hence relevant for conservation. Paper I thus experimentally explores the structure, expression and plasticity of personality in captive European minks. Thereafter paper II investigates if personality affects survival of reintroduced captive-bred animals and if spatiotemporal conditions affects the relationship between personality and survival. Paper III experimentally explores individual dietary specialism and learning in relation to novel prey as this could also impact survival. One of the main threats to the European mink is displacement by the invasive American mink (Neovison vison) wherefore management of American mink is important for European mink conservation. Paper IV hence analyses survey data to study whether native otters and red foxes can suppress American mink populations in north-eastern Europe. In the results three personality trait domains were identified in the European mink: boldness, exploration and sociability. The domains were repeatable but plastic between the non-breeding and breeding season. Reintroduced personality-tested animals survived longer if they were bolder but the effect of exploration was either positive or negative depending on spatiotemporal conditions. This is not only interesting for conservation but provides new insights on how individual behavioural differences could be maintained over evolutionary time. Whilst exploration is likely to be maintained by fluctuating selection pressures, the mechanism seem to vary with domain. The feeding experiments revealed diet choices similar to those found in wild individuals as there were both generalists and different types of specialists. Still, individuals differed in learning time towards novel but natural prey, suggesting that reintroduced animals might differ in their ability to find food after release. This could affect survival also and be related to personality. Survey data revealed that American mink abundances were suppressed by those of red foxes. Previous studies show that foxes are suppressed by lynx, and the abundance pattern of mink in relation to red fox found here indicate the existence of a predator cascade as mink were most abundant where lynx were abundant and vice versa. In several regions in the study area population dynamics indicated either exploitation or interference competition as probable mechanisms whereby foxes suppress minks. However, in many regions there were no relationships between dynamics. This could be due to that exploitation and interference competition might occur simultaneously and thus cancel each other out in the dynamics. Overall this thesis shows the importance of considering individual traits in conservation efforts, and also provides knowledge on the structure, plasticity and evolution of personality. As American mink was suppressed by foxes, management efforts might be most beneficial for species impacted by the mink if they to a larger extent are undertaken in areas with low fox abundances. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 4: Manuscript.</p>

The aim of my thesis was to evaluate two methods of monitoring of the American mink and polecat, monitoring with live traps and by floating rafts. While the first method is commonly used in our country, where the second method is the pilot project here, but it has been used in the UK successfully. Observation was from August to November in 2008 and from April to November in 2009. Observation took place in the area near PP Černíč near Dačice, where were chosen 4 different habitats. All detected tracks of Mustelids found on rafts were from the American mink. It corresponds with captures, where were captured also only minks and no polecat. Occupation of rafts was higher in 2008 than in 2009 because of the eradication of mink in November 2008. In both years the highest occupancy rate in rafts was in September and the lowest in October. There were differences between habitats and number of captured minks and tracks. In compare between rafts and traps, rafts were more successful method.

<p>A well, situated on Listerlandet in the western part of Blekinge in Sweden, has a very high content of nitrate. Water with a too high content of nitrate is hazardous to human health, in particular to small children. The area surrounding the well is mostly drained agricultural land with some larger farms for chicken and mink. The well takes its water from the bedrock and is deeper than most other wells affected by nitrate. The bedrock in the area is dominated by limestone with a relatively high flow of water.</p><p>This thesis was performed in order to find the source of the nitrate. A groundwater model, simulating the water flow, was created. The model was used to trace the particles flowing to the well in order to find the most likely source. GMS Modflow and Modpath were used to create the model.</p><p>The validation of the model shows that the model is good enough to be used for further investigation of the groundwater in the area.</p><p>The model result indicates that the original source for most of the nitrate is some large mink farms situated on the slope of a hill south of the well. Calculation shows that it takes the water 25 years to flow from the farms to the well. There is also a probable contribution of nitrate from the agriculture in the vicinity of the well. But an extensive drainage system brings most of the water from the cultivated area into the Baltic Sea.</p><p>Conclusions are that a large amount of mink farms placed in a small area contributes to the high content of nitrate in the well. Further examinations are needed to show which measures should be taken in order to diminish the content of nitrate in the well.</p> / <p>En brunn som förser Hörvik med dricksvatten har en hög halt av nitrat. Hörvik ligger på Listerlandet i västra Blekinge. Vatten med för hög nitrathalt är hälsovådligt för människor i allmänhet och spädbarn i synnerhet.</p><p>Området som omger brunnen består till största delen av dränerad jordbruksmark med några större djurgårdar för broiler och mink. Brunnen är bergborrad och går djupare än de flesta andra nitratpåverkade brunnar i Sverige. Berggrunden i området domineras av kalkberg med ett relativt högt vattenflöde.</p><p>Ett projektarbete utfördes för att ta reda på ursprungskällan till nitratet. I arbetet skapades en grundvattenmodell som skulle simulera vattenflödena i området och sedan spåra en partikels väg till brunnen för att ta reda på den mest troliga källan. GMS Modflow och Modpath är de dataverktyg som användes.</p><p>Valideringen av modellen visar att den fungerar tillfredsställande och kan användas för fortsatta undersökningar av grundvattenförhållanden i området.</p><p>Modellresultat tyder på att ursprungskällan för den största delen av nitratet är några stora minkfarmar som ligger på en sluttning upp mot Listers huvud söder om brunnen; dock har det tagit ca 25 år för vattnet att ta sig från ursprungskällan till brunnen. Jordbruket i närheten av brunnen bidrar sannolikt med en del nitrat, men en omfattande dränering leder den större delen av vattnet från jordbruksområdet ut i Östersjön.</p><p>Slutsatsen är att ett stort antal minkfarmar i ett begränsat område är en bidragande orsak till brunnens höga nitrathalt. Vidare undersökningar bör visa vilka åtgärder som behövs för att minska nitrathalten i brunnen.</p>

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that are recognized as global environmental contaminants and a potential health risk. They have been shown to elicit neurodevelopmental toxicity through disruption of the cholinergic neurotransmitter system in rodent models, but the effects of environmentally relevant exposures in wildlife species are unknown. The objective of this study was to assess the effects of the commercial pentabrominated diphenyl ether mixture DE-71 on cholinergic parameters in captive mink (Mustela vison) following dietary exposure of adult females and in utero, lactational and dietary exposure of their offspring. Adult females were fed diets containing 0, 0.1, 0.5 or 2.5 μg/g DE-71 from four weeks prior to breeding through weaning of their kits at six weeks of age. A portion of the weaned kits were maintained on their respective diets through 27 weeks of age. Cholinergic neurochemical biomarkers, including muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (mAChR) binding, cholinesterase (ChE) activity and acetylcholine (ACh) concentration, were assayed in the cerebral cortex, and ChE activity measured in the plasma. Results indicated no significant effects of DE-71 on cholinergic parameters in the cerebral cortex, but a 3-fold increase in ChE activity in the plasma of adult females in the 2.5 μg/g DE-71 group. There were also no direct effects of DE-71 on mAChR or mAChR binding or ChE activity in the enzyme and receptor fractions from the whole brain of untreated mink following in vitro exposure to 0-23.6 nM DE-71. This study demonstrated that environmentally relevant exposures to DE-71 did not affect key parameters of the cholinergic neurotransmitter system in the brain of captive mink.

Genom en difference-in-differences analys undersöker denna studie hur den finska pälsmarknaden påverkades av avlingen av danska minkar år 2020. I november 2020 upptäcktes coronaviruset hos ett antal danska minkfarmer. För att förhindra smittspridning beslutade sig den danska regeringen för att avliva alla minkar i landet. Totalt avlivades omkring 15,7 miljoner minkar. Innan avlivningen stod Danmark för 40% av den globala minkproduktionen. Enligt ekonomisk teori om utbud och efterfrågan borde denna stora negativa utbudschock som kom av avlivningen av danska minkar, resultera i prishöjningar på substitutvaror till dansk minkpäls. I denna studie utgörs denna substitutvara av minkpäls från Finland. Utifrån teorin förväntas således priset på finsk minkpäls stiga i jämförelse med prisutvecklingen i perioden innan utbudschocken, som en effekt av avlivningen på danska minkar. Resultaten från analysen visar att priset på finsk minkpäls har stigit med 84,75 %. Effekterna från chocken var som störst i juni 2021 med en prisökning på 129,8 %, och började sedan avta. / This study examines how the Finnish fur market was affected by the culling of Danish minks in 2020. This will be evaluated through a difference-in-differences analysis. In November 2020, the coronavirus was discovered at some of Denmark's mink farms. In order to prevent the virus from spreading, the Danish government decided to euthanize all minks in the country - in total around 15,7 million minks. Before the culling, Denmark accounted for 40 % of the global production of mink fur. According to economic theory of supply and demand, this large negative supply shock that came with the culling of Danish mink, should result in a price increase in substitutional goods. In this study, the substitutional good is Finnish mink fur, and the hypothesis will therefore be an increase in prices in mink fur from Finland after the supply shock, compared to the period before. The results show that the price of Finnish mink fur has increased by 84,75 % after the shock. The effect was at its greatest in June 2021, showing a price increase by 129,8 %, which decreased afterwards.

No description available.

The release of pollutants by the oil sands industry and pulp and paper mills has been an ongoing environmental concern for decades. Such toxins have been linked to declining reproductive and skeletal health in wildlife species, as they have known endocrine disrupting properties that interfere with hormones responsible for proper reproduction and bone development. As such, declining population sizes because of pollutant exposure has been correlated with altered bone health in mammals. For the purposes of environmental monitoring, the development of a biomarker of pollutant exposure would be a beneficial tool to assess pollution impact on wildlife populations. Therefore, the purpose of this research was to identify this biomarker in the American mink based on measures of their bone health. Mink from the Athabasca Oil Sands Region and an area surrounding a pulp and paper mill in Quebec were collected. From each mink, a hindlimb femur and the baculum (for males) were dissected. Bones were evaluated through a series of tests to quantify key cortical and cancellous bone structural and material properties. These included dimensional analysis, three-point bending and micro-Computed Tomography. Toxicology reports of trace element exposure levels in the minks were also provided by ECCC. Principal component analyses and correlation matrices were used to identify potential relationships between the bone metrics and trace element levels, followed by linear regression modeling. Results found that the baculum and femur structural properties were correlated with selenium, rubidium and iron concentrations, suggesting that these elements had the strongest influences on bone health for the mink studied here. This work provides the basis for future research on identifying a biomarker determinant of bone health to be used in environmental monitoring effects programs. The results here indicate that baculum bone measures are dominated by trace element effects rather than loading effects and are thus a useful bone to investigate for biomonitoring programs. This will provide a simple and reliable method for determining whether there are unsustainable levels of pollution in regions across North America. / Thesis / Master of Applied Science (MASc) / Environmental pollution in regions across Canada puts the health of communities and wildlife at risk. To better measure the impact of pollution in these regions, the implementation of a species monitoring program would benefit those communities who are at the greatest risk. Therefore, this research was aimed at developing an indicator of harmful pollution exposure in mink, an abundant species in Canada, by investigating their bone health. A group of mink from Alberta and Quebec were collected and their femur and penile bones tested for a variety of bone health measurements. In addition, information on the heavy metal levels in the mink livers were provided. The bone health measurements and heavy metal levels were then compared to look for any relationships between them. This research found that selenium, rubidium and iron had the strongest effects on bone health. The methods used have set the groundwork for using minks to monitor pollution levels across North America.

As gorduras são componentes importantes em dietas para carnívoros, porém o aproveitamento pelos animais sofre influência de fatores inerentes à composição das dietas, principalmente fibras e minerais, que precisam ser melhor estudados. Os trabalhos que avaliam as perdas endógenas de gordura nas fezes (PEGF) e os efeitos na digestibilidade aparente da gordura são escassos e divergentes. Desta forma, os objetivos destes estudos foram: determinar as PEGF em cães e mink; utilizar as PEGF para obtenção dos valores de digestibilidade verdadeira da gordura; além de avaliar os efeitos da composição de fibras dietéticas e a inclusão de emulsificantes no aproveitamento da gordura por cães. No primeiro estudo, as PEGF foram mensuradas em cães adultos. Dietas com níveis crescentes de gordura de frango foram utilizadas e as PEGF dos cães foram determinadas a partir de análises de regressão. As PEGF foram expressas em relação ao peso corporal (PC) dos animais, 155 mg/kg PV/dia, ou em relação ao consumo de gordura na matéria seca (MS), 7,9 g/kg MS consumida. A digestibilidade aparente total da gordura apresentou aumento conforme o consumo. A digestibilidade verdadeira total da gordura, corrigida para PEGF, não variou mediante o consumo de gordura. A relação entre PEGF e consumo de gordura foi maior em dietas com baixa gordura e explica o aumento na digestibilidade aparente da gordura quando concentrações maiores são consumidas. No segundo estudo, as PEGF foram determinadas em mink. Dietas com níveis crescente de óleo de soja foram formuladas e as PEGF avaliadas por regressão. Foi obtido o valor de 0,5 g/100g MS consumida, próximo ao relatado em cães. No terceiro estudo foi avaliada a influência das fibras dietéticas e da lecitina de soja na digestibilidade aparente da gordura em dietas para cães adultos. Foram avaliadas três fontes de carboidratos, amido de milho, celulose e polpa de beterraba, combinadas ou não à lecitina de soja. A polpa de beterraba reduziu a digestibilidade aparente e verdadeira da gordura em cães, aumentou o teor de umidade e elevou o escore fecal, porém ainda dentro da faixa considerada ideal. A lecitina de soja não apresentou efeito de melhora na digestibilidade dos macronutrientes e da energia das dietas. / Fats are important components of carnivores diets, however inherent factors of diets composition, mainly fibers and minerals, may affect its use by the animals, requiring further studies. Studies evaluating endogenous fat loss (EFL) and the effects on apparent total tract digestibility of fat are limited and divergent. The objectives of these studies were: to determine the EFL in dogs and mink; apply the EFL to calculated the true total tract digestibility of fats; and to evaluate the effects of dietary fiber composition and an emulsifying agent on fats digestibility in dogs. On the first study, the EFL was evaluated in adult dogs. Diets with increasing levels of poultry fat were used and the EFL was determined by regression analysis. The EFL was obtained according to the dogs’ body weight (BW) as 155 mg/kg BW/day, or according to dry matter (DM) fat intake, as 7.9 g/kg DM intake. The apparent total tract digestibility of fat increases according to the intake level. However, the true total tract digestibility of fat, EFL corrected, remained unaffected by fat intake. The relation between EFL and fat intake is higher for low fat diets and explains why the apparent digestibility increases according to intake. On the second study, the EFL was measured in mink. Diets with graded levels of soybean oil were offered and the EFL evaluated by regression. The value of 0.5 g/100 g DM intake was obtained, close to the reported with dogs. The third study assessed the influences of dietary fibers and soy lecithin on apparent total tract digestibility of fat in adult dog diets. Were evaluated three carbohydrate sources; corn starch, cellulose and beet pulp; combined or not with soy lecithin. The beet pulp decreased apparent and true total tract digestibility of fat in dogs, increased the moisture level of faeces and the faecal score, yet the faeces still had good quality. The soy lecithin did not improve digestibility of macronutrients and energy of diets.

Darbo tikslas – išanalizuoti audinių šėrimą bei jo ypatumus, panaudojant racionus su skirtingu baltymų kiekiu ir skirtingu maisto medžiagų santykiu juose, stebėti laktuojančių audinių pieno produkcijos lygį, audinukų augimo spartą bei išsivystymą. Bandymo uždaviniai buvo: 1. Atrinkti analoginius gyvūnus ir juos suskirstyti į analogines grupes; 2. Sekti audinių pašarų ėdamumą ir laikymo sąlygas; 3. Sekti audinių pieno produktyvumą pagal atskiras grupes, nes kiekvienos grupės audinės buvo šeriamos skirtingais racionais pagal maisto medžiagų santykį; 4. Stebėti audinukų kūno masės priaugimą, kada jie buvo maitinami tik motinos pienu ir auginimo pabaigoje, t.y. įvertinti augimo ir vystimosi spartą. Tyrimus atlikome Lietuvos žvėrininkystės individualioje fermoje su audinėmis Mustela vison. Visos audinės buvo suskirstytos į 3 grupes: I gr. - racionas su dideliu baltymų kiekiu, II gr. - racionas su vidutiniu baltymų kiekiu, II gr. - racionas su mažu baltymų kiekiu. Šeriant audines skirtingais racionais, kur skyrėsi maisto medžiagų santykis: baltymai-riebalai-angliavandeniai nuo energijos kiekio, pirmoje grupėje buvo 63:35:2; antroje grupėje 45:41:14 ir trečioje grupėje 29:44:27, galime padaryti sekančias išvadas: 1. nustačius naudojamų pašarų maistinę ir energetinę vertes, baltymų didžiausias kiekis buvo pirmos grupės audinių racione ir sudarė 66,1 proc., nes jų racione buvo daugiau kaip 60 proc. žuvies ir žuvų produktų. Kitų grupių audinių racionuose riebalai ir angliavandeniai... [toliau žr. visą tekstą] / The aim of this work is to analyze the foddering of minks and its peculiarity, using rations with different amount of albumen and different proportion of nutritious matter in it; to watch the level of milk production during the period of mink lactation; to watch the speed of baby mink growing up and development. The tasks of the experiment: 1. To choose analogical animals and divide them into analogical groups; 2. To watch the fitness of mink fodder and their keeping conditions; 3. To watch the mink milk productivity in different groups because minks in every group were foddered on different rations according to the proportion of nutritious matter; 4. To watch baby mink gaining weight when they are fed on mother’s milk and at the end of mink breeding. The aim of it is to estimate the speed of growing up and development. The experiment was done in the individual farm of fur farming in Lithuania with Mustela Vison minks. All minks were divided into three groups: 1st group – ration with big amount of albumen; 2nd group – ration with average amount of albumen and 3rd group – ration with little amount of albumen. Foddering minks on various rations, where the proportion of nutritious matter was different: albumen – fat – carbohydrate from the amount of energy, in the 1st group it was 63:35:2; in the 2nd group 45:41:14 and in the 3rd group it was 29:44:27. After the experiment the following conclusions can be made: 1) When the nutritional and energetic value was settled, the biggest... [to full text]

Darbo tikslas : Išanalizuoti AB „Vilkijos ūkis“ naudojamas žvėrelių auginimo technologijas, ekonominius veiklos rezultatus ir įvertinti ūkio plėtros galimybes bei rizikos veiksnius. Darbo uždaviniai: 1. išanalizuoti brangiakailės žvėrininkystės būklę Lietuvoje ir pasaulyje; 2. apžvelgti pagrindinius veiksnius, darančius įtaką brangiakailius žvėrelius auginančių ūkių produkcijai (auginimo technologijos, ligos, bandos formavimas); 3. išanalizuoti ir įvertinti žvėrininkystės ūkio ekonominę padėtį ir galimybes kailių rinkoje. Tyrimo metodai ir sąlygos. Lapių ir audinių auginimo technologijų ir kailių rinką įtakojančių veiksnių teoriniams tyrimams buvo analizuota, apibendrinta, sisteminta ir lyginta mokslinė literatūra. Tyrimams buvo naudojami AB „Vilkijos ūkis“ 2004 – 2007 m. ūkinės veiklos duomenys. Praktinė tyrimo dalis yra paruošta naudojant pirminės ir antrinės informacijos sisteminimo, apibendrinimo bei matematinius statistinius duomenų apdorojimo metodus. Duomenų analizei naudoti duomenų grupavimo, apibendrinančių rodiklių sudarymo metodai. Buvo skaičiuojama dinamikos eilutės vidutiniai rodikliai, vidurkiniai lygiai, absoliutiniai dinamikos eilutės pokyčiai, pokyčio tempai. Taip pat taikėme grafinės analizės metodą. Statistiniai rodikliai apskaičiuoti naudojant skaičiuoklę Excel. Tyrimo rezultatai : 1. Visi Lietuvoje brangiakaile žvėrininkyste užsiimantys ūkiai produkciją realizuoja vienodomis sąlygomis – užsienio aukcionuose. Skirtingų rūšių kailių paklausa ir kaina... [toliau žr. visą tekstą] / Objectives: Analyze fur bearing animals breeding technologies, results of economic activity in „Vilkijos ūkis“, assess the posibilities of farm development and risk factors. Tasks: 1. Analyze the condition of fur animal husbandry all over the world and in Lithuania; 2. Overlook main factors influencing the production of fur breeding farms (breeding technologies, diseases, herd formation); 3. Analyze and assess the economic situation of fur breeding farms and opportunities in fur market. Material and methods. Scientific literature was analyzed, structured and compared for theoretical research of factors influencing breeding technologies and fur market of foxes and minks. Economical activity data of „Vilkijos ūkis“ (2004 - 2007) was used in this research. Practical part of the research is prepared using mathematical statistical data processing methods of primary and secondary information systematization and generalization. Data batching, resumptive rates formation methods were used for data analysis. There was used calculation of dynamics line average indexes, average levels, absolute alterations of dinamics lines, alteration rates. Results of the work: 1. All fur breeding animal farms in Lithuania sell their production in equal conditions – foreign auctions. Demand and price of different fur kinds is very hesitative, because fur market is dictated by heavily forecasted factor – fashion trends; 2. Amounts of farm production are stable – though general number of fur... [to full text]