Reproductive and molecular ecology of the European lobster: Implications for conservation management

The European lobster (Homarus gammarus) is an ecologically important benthic decapod which supports fisheries that are critical to the economic prosperity of coastal communities. However, populations across its range are pressured by rising exploitation, from which management has failed to prevent stock collapses in the recent past. Fisheries management of the species is significantly hindered by deficiencies in our knowledge of fundamental characteristics of population biology, including the connectivity and genetic diversity of stocks. As a result, the effectiveness of strategies designed to conserve recruitment and ensure harvests are sustainable is poorly understood. This thesis focuses on elucidating aspects of reproductive and molecular ecology in H. gammarus which can be used to inform and appraise conservation management initiatives, currently applied via both the regulation of capture and the wild release of hatchery-reared juveniles. The size-specific fecundity of reproducing females was defined around southwestern UK, and spatial variation in clutch size between populations was linked to a longitudinal gradient in oceanic temperature range across Northern Europe. The reconstruction of paternal genotypes show that single males fertilise individual clutches, which hints at demographic stability within a productive Atlantic fishery. Population genetic structure, investigated at a fine spatial scale in the same region, evidenced high connectivity and suggests that the localised interventions of an active hatchery do not lead to juveniles being released beyond areas they might naturally recruit via planktonic dispersal. However, genetic differentiation and isolation-by-distance at a broad geographic scale indicate that direct gene flow between remote populations is limited, so that (i) a failure to maintain spawning stock biomass may negatively affect local recruitment, (ii) the utilisation of non-resident broodstock for hatchery stocking may cause a loss of adaptive potential, and (iii) the recovery of depleted stocks is likely to be problematic. Finally, simulations indicated that genetic parentage assignment will prove accurate in distinguishing cultured individuals from natural stock among admixed populations in the wild, an important development that should facilitate the optimisation of hatchery stocking and lead to rigorous assessments of the conservation value of releasing lobsters reared in captivity.European Social FundThe Fishmonger's Compan

International mammal trapping standards ̶ Part II: Killing Trap Systems

In this paper, we propose standards for killing trap systems based on Proulx et al.’s (2022) prerequisites, which provide context and explanations for our approach. Our aim is to identify assessment protocols that are based on the scientific method, and that include evaluation parameters and threshold levels of acceptation, and laboratory and field procedures, to recognize mammal trapping systems that are acceptable from an animal welfare, and capture efficiency and selectivity, point of view. The testing of killing trap systems consists of 4 steps: 1) Mechanical evaluation; 2) Approach tests in semi-natural environments; 3) Kill tests in semi-natural environments; and 4) Kill tests on traplines. Based on the normal approximation to the binomial distribution, acceptable killing trap systems are expected, at a 95% confidence level, to render ≥85% of the animals irreversibly unconscious in ≤ 90 sec for most mammal species, and ≤30 sec for small mammals (mouse, vole, etc.). We recommend that standards be continuously updated based on the development of new designs and technology

International mammal trapping standards ̶ Part I: Prerequisites

In this paper, we set out the prerequisites for the development of killing and restraining trap systems to capture mammals for research, wildlife management and conservation, fur trapping, animal control, and any other activity involving the trapping of a mammal in a mechanical trapping device. We selected them with the main intent of developing new trapping standards that will improve animal welfare as per our current state of knowledge, and with realistic, achievable objectives based on state-of-the-art trapping technology. The proposed new standards should be applicable to all terrestrial and semi-aquatic mammal species. They should be based on animal testing in semi-natural environments and on traplines, with high trap thresholds of acceptance, low times to irreversible unconsciousness for killing trap systems, an understanding of the impacts of trapping on physical form, behaviour and physiological function, adequate trap checking times and handling of the captured animals, and high capture selectivity. Furthermore, the implementation of improved trapping standards would include the mandatory publication of findings for peer-review and public education. We believe that the prerequisites that we lay out for the development of new mammal trapping standards will address many of the welfare concerns voiced by the scientific community and the public in the last two decades. It will lead to improved animal welfare and spur continuous improvement in the efficacy and innovation in trapping technology

Neurotoksiliste insektitsiidide subletaalne toime põllumajanduslikult oluliste jooksiklaste põhikäitumistele

A Thesis for applying for the degree of Doctor of Philosophy in AgricultureSublethal effects of pesticides on behavioural endpoints are poorly investigated in nontargeted beneficial arthropod predators important as nartural enemies of many agricultural pests. In this ecotoxicological study, deleterious short- long-term effects of neurotoxic pyrethroid and neonicotinoid insecticides on various basic behaviours of the predatory carabid Platynus assimilis Paykull (Coleoptera, Carabidae) were quantified over a broad range of sublethal concentrations and doses in controlled laboratory conditions. It appeared that low doses of alpha-cypermethrin and thiamethoxam may cause a number of substantial short- and long-term abnormalities in many basic behaviours such as locomotor activity (LA), general motor activity (GMA), clean food consumption rate (CFCR) and behavioural thermoregulation of carabids. The observed sublethal behavioural biases may lead to deterioration of ecological fitness and population dynamics of the beetles in agricultural lands where these chemicals are applied. For the first time in predatory arthropods, it was was demonstrated that in addition to locomotion, other important behavioural endpoints such GMA, CFCR and behavioural thermoregulation may serve as sensitive, valuable and easily quantifiable ecotoxicological biomarkers mirroring different rates and aspects of toxic stress. The observed remarkable declines in CFCR and efficiency for behavioural thermoregulation of the beetles exposed to sublethal doses of alpha-cypermethrin and thiamethoxam may directly worsen performance of the carabids as natural enemies of pest insects in the insecticide treated fields. Thus, the results of this study may have importance in integrated pest management programs promoting reduced insecticide use and encouraging natural pest control mechanisms wherever possible. The results of this PhD thesis are published in three papers.Ehkki röövtoidulistel lülijalgsetel on põllumajandusmaastikel tähtis roll taimekahjurite arvukuse vähendamisel, on insektitsiidide madalate dooside kõrvalmõjusid nende käitumisele seni vähe uuritud. Käesolevas doktoritöös mõõdeti esmakordselt neurotoksilise püretroidse ja neonikotinoidse insektitsiidi lühi- ja pikaajalisi mõjusid röövtoidulise süsi-ketasjooksiku (Platynus assimilis, Coleoptera: Carabidae) erinevatele põhikäitumistele. Mardikaid töödeldi preparaatide Fastac 50EC® (toimeaine alfa-tsüpermetriin) ja Actara 25WG® (toimeaine tiametoksaam) erinevate subletaalsete kontsentratsioonide ja doosidega kontrollitud laboritingimustes. Katsed näitasid, et jooksiklased on töös testitud insektitsiidide suhtes ülimalt tundlikud. Isegi väga madalad doosid põhjustasid mitmeid olulisi lühi- ja pikaajalisi negatiivseid kõrvalekaldeid mardikate põhikäitumistes. Täheldati märkimisväärset langust mardikate puhta toidu tarbimismääras ning käitumusliku termoregulatsiooni võimes, mis põllumajandusmaastikel võivad otseselt halvendada nende kasulike putukate ökoloogilist kohasust, populatsiooni dünaamikat ja biotõrje efektiivsust. Esmakordselt demonstreeriti, et putukate põhikäitumised nagu üldmotoorne aktiivsus, käitumuslik termoregulatsioon ja puhta toidu tarbimismäär on tundlikud, väärtuslikud ja kergesti mõõdetavad ökotoksikoloogilised biomarkerid, mis lisaks lokomotsioonile aitavad hinnata röövtoiduliste jooksiklaste toksilise stressi erinevaid tasemeid ja aspekte. Saadud tulemusi tuleks kindlasti arvestada integreeritud taimekaitse programmide väljatöötamisel, mis soodustavad kultuurtaimede töötlemist insektitsiidide vähendatud doosidega ja taimekahjurite looduslike vaenlaste maksimaalset ärakasutamist, kus iganes võimalik. Antud doktoritöö tulemused avaldati kolmes teadusartiklis.Publication of this thesis is supported by the Estonian University of Life Sciences, Chair of Plant Healt

Dental morphology and mechanical efficiency during development in a hard object feeding primate (Cercocebus atys)

Teeth play a prominent role in food acquisition and processing by providing the working surfaces to initiate and propagate fracture. Variation in the shape and size of teeth has therefore naturally been associated with various dietary adaptations. However, few studies have actually tested the functional consequences of tooth form on food breakdown. The work presented in this thesis uses a combination of shape quantification and physical testing to further our understanding of the relationship between dental occlusal morphology and food breakdown in the dietary specialisation hard object feeding. The sooty mangabey, Cercocebus atys, is a primate that specialises in hard object feeding throughout its life, and so presents an interesting study group that will be of focus in this thesis. Individual cusps which vary in angle and bluntness performed differently (in terms of force, energy, duration and fragmentation) during food breakdown physical testing. Therefore trade-offs in dental occlusal morphology may have to occur when optimising for more than one performance criteria. This may in part explain the diversity of tooth form observed in hard object feeders. The morphology of C. atys molars changes considerably with age due to wear, with high sharp cusps in the juveniles wearing down to produce dentine pools surrounded by an enamel ridge in older individuals. Given the considerable change in dental occlusal morphology due to wear, performance is minimally effected in hard hollow object feeding, this is particularly relevant for the dietary ecology of C. atys suggesting functional equivalence in the tooth as it wears. This study reveals a complex relationship between dental occlusal morphology and dietary ecology

Does a Hypertrophying Muscle Fibre Reprogramme its Metabolism Similar to a Cancer Cell?

In 1924, Otto Warburg asked “How does the metabolism of a growing tissue differ from that of a non-growing tissue?” Currently, we know that proliferating healthy and cancer cells reprogramme their metabolism. This typically includes increased glucose uptake, glycolytic flux and lactate synthesis. A key function of this reprogramming is to channel glycolytic intermediates and other metabolites into anabolic reactions such as nucleotide-RNA/DNA synthesis, amino acid-protein synthesis and the synthesis of, for example, acetyl and methyl groups for epigenetic modification. In this review, we discuss evidence that a hypertrophying muscle similarly takes up more glucose and reprogrammes its metabolism to channel energy metabolites into anabolic pathways. We specifically discuss the functions of the cancer-associated enzymes phosphoglycerate dehydrogenase and pyruvate kinase muscle 2 in skeletal muscle. In addition, we ask whether increased glucose uptake by a hypertrophying muscle explains why muscularity is often negatively associated with type 2 diabetes mellitus and obesity

Biochemical enrichment and biophysical characterization of a taste receptor for L-arginine from the catfish, Ictalurus puntatus

BACKGROUND: The channel catfish, Ictalurus punctatus, is invested with a high density of cutaneous taste receptors, particularly on the barbel appendages. Many of these receptors are sensitive to selected amino acids, one of these being a receptor for L-arginine (L-Arg). Previous neurophysiological and biophysical studies suggested that this taste receptor is coupled directly to a cation channel and behaves as a ligand-gated ion channel receptor (LGICR). Earlier studies demonstrated that two lectins, Ricinus communis agglutinin I (RCA-I) and Phaseolus vulgaris Erythroagglutinin (PHA-E), inhibited the binding of L-Arg to its presumed receptor sites, and that PHA-E inhibited the L-Arg-stimulated ion conductance of barbel membranes reconstituted into lipid bilayers. RESULTS: Both PHA-E and RCA-I almost exclusively labeled an 82–84 kDa protein band of an SDS-PAGE of solubilized barbel taste epithelial membranes. Further, both rhodamine-conjugated RCA-I and polyclonal antibodies raised to the 82–84 kDa electroeluted peptides labeled the apical region of catfish taste buds. Because of the specificity shown by RCA-I, lectin affinity was chosen as the first of a three-step procedure designed to enrich the presumed LGICR for L-Arg. Purified and CHAPS-solubilized taste epithelial membrane proteins were subjected successively to (1), lectin (RCA-I) affinity; (2), gel filtration (Sephacryl S-300HR); and (3), ion exchange chromatography. All fractions from each chromatography step were evaluated for L-Arg-induced ion channel activity by reconstituting each fraction into a lipid bilayer. Active fractions demonstrated L-Arg-induced channel activity that was inhibited by D-arginine (D-Arg) with kinetics nearly identical to those reported earlier for L-Arg-stimulated ion channels of native barbel membranes reconstituted into lipid bilayers. After the final enrichment step, SDS-PAGE of the active ion channel protein fraction revealed a single band at 82–84 kDa which may be interpreted as a component of a multimeric receptor/channel complex. CONCLUSIONS: The data are consistent with the supposition that the L-Arg receptor is a LGICR. This taste receptor remains active during biochemical enrichment procedures. This is the first report of enrichment of an active LGICR from the taste system of vertebrata