This dissertation examines how in eighteenth-century Europe, naturalists sought to study, grasp and capture the world of fish. Working on the intersection of the history of science and book history... Show moreThis dissertation examines how in eighteenth-century Europe, naturalists sought to study, grasp and capture the world of fish. Working on the intersection of the history of science and book history, this research aims to shed light on how naturalists came to present themselves as authorities in an emerging field. It does so by focussing on a set of ‘fish books’, i.e., natural historical works that describe and depict fish. The first is Francis Willughby and John Ray’s "Historia piscium" (Oxford, 1686); the second Peter Artedi’s "Ichthyologia sive opera omnia de piscibus" (Leiden, 1738), and the third Marcus Élieser Bloch’s twelve volume series "Allgemeine Naturgeschichte der Fische" (Berlin, 1782–1795). These works are analysed alongside correspondences, manuscripts and natural historical collections. Together, these sources show that the development of the study of fish in this period can be best be understood as a process of continuous demarcation. This dissertation argues that the study of fish was subject to recurrent debates on subject, method and practitioner, and that such discussions were of both epistemological and social nature. In presenting their fish books, naturalists leveraged such discussions as to secure a place for themselves in the capricious environment of early modern natural history. Show less
Anthropogenic noise has been shown to affect marine animals in various ways, this may have fitness consequences at individual and population level. This thesis aims to increase insight into the... Show moreAnthropogenic noise has been shown to affect marine animals in various ways, this may have fitness consequences at individual and population level. This thesis aims to increase insight into the quantification of sound-induced behavioural responses that are relevant to fitness, and into factors that modulate the responses. I addressed both knowledge gaps using captive and field studies on marine animals from multiple trophic levels. For the quantification of behavioural responses relevant to fitness, I examined the changes in time budgets of Atlantic cod in a net pen and basin in response to sound (chapter 2 and 3). To increase insight into factors that modulate sound impact, I examined the effect of various acoustic characteristics of sound stimuli and the environment on European seabass (chapter 4), the interaction between foraging shore crabs and common shrimps during noise (chapter 6), the cross-sensory interference by noise in foraging crabs (chapter 7), and habituation to repeated sound exposures by blue mussels (chapter 8). Future studies are needed to be able to link changes in time budgets to changes in energy budgets, and consequently to fitness. Additionally, studies into the factors that modulate the effects of sound are needed to fully understand the impact of sound. Show less
The effects of anthropogenic noise on interactions between predators and their prey are still little understood. This thesis aims to fill pressing knowledge gaps on this topic by studying how... Show moreThe effects of anthropogenic noise on interactions between predators and their prey are still little understood. This thesis aims to fill pressing knowledge gaps on this topic by studying how anthropogenic noise affected various stages in the prey-hunting of predators and the predator-avoidance of prey. For predators, I investigated whether an¬thropogenic noise could influence habitat choice (chapters 2 and 3), foraging efficiency (chapter 3) and communication between foraging group members (chapter 4). For prey, I studied how anthropogenic noise affected prey behaviour outside of predation con¬texts (chapter 5) and if current and previous vessel noise exposure affected anti-predator behaviour when a simulated predator attacked (chapter 6). The multi-disciplinary studies of this thesis combine to unravel more insight into the influence of noise on predator-prey relationships in the marine environment. Further investigations should focus on revealing the mechanistic underpinning of noise effects on behaviour of both predator and prey. Only then will we be able to reduce the impact of noise on marine ecosystems. Show less
There is a fundamental difference between mammals and fish in how hypoxia affects the lipid metabolism by means of the stress hormone noradrenaline. In mammals, hypoxia induces an increase in lipid... Show moreThere is a fundamental difference between mammals and fish in how hypoxia affects the lipid metabolism by means of the stress hormone noradrenaline. In mammals, hypoxia induces an increase in lipid metabolism, which can eventually lead to tissue damage due to elevated plasma fatty acid levels, e.g. in case of a heart attack. However, hypoxia is not a normally occurring situation in healthy mammals as opposed to many fish species, because water is a relative poor source of oxygen. In hypoxic fish therefore, noradrenaline mediates a decrease in lipid metabolism, and we believe that this is a general protection mechanism in fish against lipid poisoning. There is a clear difference in the mode of breathing between mammals and fish, namely air- vs. water-breathing. Hence, we hypothesise that this difference is the cause for the opposing effects of noradrenaline. Therefore, we studied the effects of hypoxia on an air-breathing fish, the African catfish. However, physiologically this species reacted the same as other water-breathing fish, namely by means of a reduced lipid metabolism. Additionally, we demonstrated that, despite the opposing effects on the lipid metabolism, the transduction pathways in fish and mammals are very alike, and thus only a minor change has occurred in the course of evolution. This research has aided in a better understanding of the evolutionary changes in lipid metabolism.|Er is een fundamenteel verschil tussen zoogdieren en vissen in hoe het vetmetabolisme onder hypoxie (=zuurstoftekort) wordt veranderd door het stresshormoon noradrenaline. In zoogdieren leidt hypoxie tot een verhoogd vetmetabolisme, wat uiteindelijk zelfs weefselschade kan veroorzaken door te hoge vetzuurgehaltes, b.v. bij een hartaanval. Gezonde zoogdieren komen normaliter niet in zuurstofnood, in tegenstelling tot veel vissoorten, omdat water een relatief arme zuurstofbron is. In hypoxische vissen daalt dan ook het vetmetabolisme door noradrenaline, en wij denken dat dit een beschermingsmechanisme is tegen een vetzuurvergiftiging. Er is een duidelijk verschil in de manier van ademhalen van zoogdieren en vissen, respectievelijk lucht- en waterademhaling, en dit verschil ligt mogelijkerwijs ten grondslag aan deze verschillende effecten van noradrenaline; dit is de centrale hypothese van het onderzoek. Daarom is gekeken naar het effect van zuurstoftekort bij een luchtademhalende vissoort, de Afrikaanse meerval. Deze vis bleek echter fysiologisch hetzelfde te reageren als waterademhalende vissen, namelijk een verlaagd vetmetabolisme. Daarnaast is aangetoond dat, ondanks tegenovergestelde effecten op het vetmetabolisme, de aansturingmechanismen in vissen en zoogdieren vergelijkbaar zijn, en dat er dus maar een minimale verandering in de evolutie heeft plaatsgevonden. Dit onderzoek heeft bijgedragen tot een beter begrip van de evolutionaire veranderingen in het vetmetabolisme. Show less
