Prof. David W. Sims | |
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![]() David Sims at the Marine Biological Association in Plymouth, 2017 | |
Born | |
Known for | Research on the behaviour of sharks |
Awards |
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Scientific career | |
Fields | Marine biology |
Institutions | |
Doctoral advisor | Quentin Bone |
Website | www |
David William Sims MAE (born 1969) is a British marine biologist known for using satellite tracking to study wild behaviour of sharks and for the Global Shark Movement Project. [1] [2] He is Senior Research Fellow at the Laboratory of the Marine Biological Association (MBA) in Plymouth, and a Professor of Marine Ecology in the National Oceanography Centre, Southampton at the University of Southampton, U.K.
He works in the field of animal ecology researching movements, behaviour and conservation of sharks. Research has estimated global spatial overlap of sharks and fisheries, climate change impacts on fishes, identified common patterns of behaviour (scaling laws) across phyla and informed conservation of threatened species. [3]
He gained a PhD in animal behaviour in 1994 under the supervision of Quentin Bone FRS at the Marine Biological Association. Between 1994 and 1995 Sims did postdoctoral research on physiology of fish behaviour with Paul L.R. Andrews and J. Z. Young FRS after which he was lecturer in marine biology at the University of Plymouth. Between 1998 and 2000 he was lecturer in the Zoology Department at the University of Aberdeen before becoming a Research Fellow at the Marine Biological Association Laboratory in Plymouth in 2000. [4]
He was made Senior Research Fellow at the Marine Biological Association in 2005, became a professor in 2008, and in 2012 was appointed jointly as professor at the University of Southampton.
Sims is also a recipient [6] of an advanced grant from the European Research Council. [7]
David Sims is known for research on the behaviour, ecology and conservation of sharks [8] studied using remote tracking technology (telemetry), for studying climate change impacts on fishes, and for making advances in the field of animal movement ecology. [9]
Beginning in 1995 Sims studied the behavioural ecology of the plankton-feeding basking shark, the world's second largest fish. [10] He showed from long-term field studies of behaviour and satellite tracking that basking sharks feed on specific assemblages of zooplankton and do not hibernate in winter, [11] [12] [13] overturning an understanding which had stood for nearly 50 years. [14] Sims' satellite tracking of basking sharks were some of the first long-term trackings of any shark species [15] and contributed directly to successful conservation proposals to list basking sharks on Appendix II of the Convention for International Trade in Endangered Species (CITES) (Feb 2003) [16] [17] and the Convention for the Conservation of Migratory Species of Wild Animals (CMS) (Nov 2005).
Basking sharks were also studied to find out how fish actually respond to variations in zooplankton prey density gradients in the ocean, showing basking sharks were useful as 'biological plankton recorders', results which were published in the journal Nature . [18] Results have demonstrated the biological significance of ocean fronts to predators, [19] which have potential as candidates for high-seas protected areas. [10]
Since 2001, Sims has also made significant contributions [20] to understanding of climate change impacts on fish populations, including how climate-driven warming has altered migration timings, [21] [22] dramatic community changes of European marine fish, [23] [24] and vertical habitat compression of sharks due to ocean deoxygenation which can increase vulnerability to longline fishing. [25]
Research has identified common scaling laws that describe movement paths and behaviour patterns of marine predators. [26] [27] [28] [29] [30]
It is argued that Sims' work has provided the strongest empirical evidence [31] [32] [33] for the existence of movement patterns that are well approximated by biological Lévy flights and Lévy walks, a special class of random walk that theoretically optimise random searches for sparsely distributed resources. [34] It is said that Sims' work has shifted the debate on biological Lévy walks from whether they exist, to how and why they arise. [32] [33] He also conducted the first empirical field tests of the Lévy flight foraging hypothesis.
In the book Bursts: The Hidden Pattern Behind Everything We Do, the physicist and best-selling author Albert-László Barabási writes: "Yet if a Lévy flight offers the best search strategy, why didn’t natural selection force animals to exploit it? In February 2008 David Sims showed that it did, in fact."
Sims' 2008 Nature paper announcing the discovery of Scaling laws of marine predator search behaviour is a Web of Science Highly Cited Paper. Since then additional evidence for biological Lévy walks has accumulated across a wide range of taxa including microbes and humans [35] and in fossil trails of extinct invertebrates, [36] suggesting an ancient origin of the movement pattern. His work contributes to the emerging understanding [37] in animal movement ecology that normal diffusion is insufficient for describing natural movements such as searching behaviour but that anomalous diffusion is required.
His studies published in Nature on Lévy and Brownian searches in ocean predators [26] [27] inspired the optimal-foraging decision process used in an optimisation algorithm – the "Marine Predators Algorithm" [38] – a high-performance optimizer with applications to engineering and medicine, including electrical modeling of photovoltaic power plants, [39] renewable-energy systems design, [40] and COVID-19 x-ray image classification. [41]
In 2016 Sims led an international team tracking ocean-wide movements of sharks. They found pelagic sharks like the shortfin mako aggregate in space-use "hotspots" characterized by fronts and high plankton biomass. [42] Data showed longline fishing vessels also targeted the habitats and efficiently tracked shark movements seasonally, leading to an 80% spatial overlap. The work suggests current hotspots are at risk from overfishing and argued for introduction of international catch limits. The results were reported widely in the media including in The Times newspaper [43] and the journal Science . [44]
He initiated the Global Shark Movement Project, an international collaboration of research groups across 26 countries. The database assembled contains over 2,000 satellite tracks of sharks and is used "to find out where sharks aggregate, how distributions are influenced by environmental variations, and the global overlap with anthropogenic threats such as fisheries".
In 2019 the team published its first results in Nature reporting a global spatial risk assessment of sharks. [45] They showed nearly one quarter of shark space-use hotspots overlap with longline fisheries each month, rising to over 60% each month for commercially valuable sharks (like shortfin mako) and internationally protected species (like great white shark). Shark hotspots were also associated with significant increases in fishing effort, leading the team to conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). They suggest large-scale marine reserves centred on shark hotspots could help to limit shark exploitation on the high seas. The paper was reported worldwide including by the BBC, [46] CNN [47] and NPR. [48]
It has been commented [49] that the paper has "provided a much-needed blueprint for conservation actions that could be used to provide sharks with safe havens in our increasingly crowded oceans".
Sims' research on basking shark behaviour was the subject of an award-winning documentary, "Email from a shark", by the Cornish film company Shark Bay Films, that aired on Sky in December 2004. The film won the British Council Youth and Science Award at the Helsingborg Film Festival, Sweden, in 2004. Sims' research has received media attention, including articles in New Scientist, Science, Science News, Physics World, and in documentaries programmes for BBC Television, such as BBC1 "Animal Camera" with Steve Leonard (10 March 2004), BBC Radio 4 Natural History Programme, Channel 5 "Nick Baker's Weird Creatures" episode 5 – the basking shark (16 February 2007), and BBC Radio 4 Inside Science (25 July 2019) presented by Adam Rutherford.
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation and parasitoidism. It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators.
Longline fishing, or longlining, is a commercial fishing angling technique that uses a long main line with baited hooks attached at intervals via short branch lines called snoods or gangions. A snood is attached to the main line using a clip or swivel, with the hook at the other end. Longlines are classified mainly by where they are placed in the water column. This can be at the surface or at the bottom. Lines can also be set by means of an anchor, or left to drift. Hundreds or even thousands of baited hooks can hang from a single line. This can lead to many deaths of different marine species. Longliners – fishing vessels rigged for longlining – commonly target swordfish, tuna, halibut, sablefish and many other species.
A Lévy flight is a random walk in which the step-lengths have a stable distribution, a probability distribution that is heavy-tailed. When defined as a walk in a space of dimension greater than one, the steps made are in isotropic random directions. Later researchers have extended the use of the term "Lévy flight" to also include cases where the random walk takes place on a discrete grid rather than on a continuous space.
The basking shark is the second-largest living shark and fish, after the whale shark. It is one of three plankton-eating shark species, along with the whale shark and megamouth shark. Typically, basking sharks reach 7.9 m (26 ft) in length. It is usually greyish-brown, with mottled skin, with the inside of the mouth being white in colour. The caudal fin has a strong lateral keel and a crescent shape. Other common names include bone shark, elephant shark, sailfish, and sunfish. In Orkney, it is called hoe-mother, meaning "the mother of the picked dogfish."
The lemon shark is a species of shark from the family Carcharhinidae and is classified as a Vulnerable species by the International Union for the Conservation of Nature. Lemon sharks can grow to 3.4 metres (11 ft) in length. They are often found in shallow subtropical waters and are known to inhabit and return to specific nursery sites for breeding. Often feeding at night, these sharks use electroreceptors to find their main source of prey, fish. Lemon sharks enjoy the many benefits of group living such as enhanced communication, courtship, predatory behavior, and protection. This species of shark gives birth to live young, and the females are polyandrous and have a biennial reproductive cycle. Lemon sharks are not thought to be a large threat to humans; there have been 10 recorded bites, none of which were life-threatening. The lemon shark's life span is unknown, but the average shark is 25 to 30 years old.
Alepisaurus ferox, also known as the long snouted lancetfish, longnose lancetfish, or cannibal fish, is a species of lancetfish found in the ocean depths down to 1,830 m (6,000 ft). This species grows to 215 cm (85 in) in total length and a weight of 9 kg (20 lb).
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or smell, sharp spines, or aggressive nature. These advertising signals may take the form of conspicuous coloration, sounds, odours, or other perceivable characteristics. Aposematic signals are beneficial for both predator and prey, since both avoid potential harm.
The nursehound, also known as the large-spotted dogfish, greater spotted dogfish or bull huss, is a species of catshark, belonging to the family Scyliorhinidae, found in the northeastern Atlantic Ocean. It is generally found among rocks or algae at a depth of 20–60 m (66–197 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fins placed far back. It shares its range with the more common and closely related small-spotted catshark, which it resembles in appearance but can be distinguished from, in having larger spots and nasal skin flaps that do not extend to the mouth.
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Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The adjective "diel" comes from Latin: diēs, lit. 'day', and refers to a 24-hour period. The migration occurs when organisms move up to the uppermost layer of the water at night and return to the bottom of the daylight zone of the oceans or to the dense, bottom layer of lakes during the day. DVM is important to the functioning of deep-sea food webs and the biologically-driven sequestration of carbon.
Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults.
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Fractal analysis is assessing fractal characteristics of data. It consists of several methods to assign a fractal dimension and other fractal characteristics to a dataset which may be a theoretical dataset, or a pattern or signal extracted from phenomena including topography, natural geometric objects, ecology and aquatic sciences, sound, market fluctuations, heart rates, frequency domain in electroencephalography signals, digital images, molecular motion, and data science. Fractal analysis is now widely used in all areas of science. An important limitation of fractal analysis is that arriving at an empirically determined fractal dimension does not necessarily prove that a pattern is fractal; rather, other essential characteristics have to be considered. Fractal analysis is valuable in expanding our knowledge of the structure and function of various systems, and as a potential tool to mathematically assess novel areas of study. Fractal calculus was formulated which is a generalization of ordinary calculus.
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The Lévy flight foraging hypothesis is a hypothesis in the field of biology that may be stated as follows:
Since Lévy flights and walks can optimize search efficiencies, therefore natural selection should have led to adaptations for Lévy flight foraging.
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Sir Ian Lamont Boyd, is a Scottish zoologist, environmental and polar scientist, former Chief Scientific Adviser at the Department for Environment, Food and Rural Affairs (DEFRA) and is a professor of biology at the University of St Andrews. He is Chair of the UK Research Integrity Office and President of the Royal Society of Biology.
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