A network analysis approach to understanding shark behaviour

The mechanisms and functions of shark grouping behaviour have received relatively little scientific attention to date. The current widespread use of social network analysis to study animal groups, in concert with rapid advances in animal tracking technology, now allows us to test specific hypotheses about how and why sharks form groups. This thesis uses replicated laboratory experiments to investigate some of the mechanisms underpinning aggregation in a model species of benthic, oviporous elasmobranch, the small spotted catshark (Scyliorhinus canicula L. 1758; Scyliorhinidae). Acoustic tracking of this species in the wild is also conducted to explore how network analyses can be adopted to study the localized movements, habitat connectivity and ranging behaviour of adult sharks. Groups of juvenile S. canicula were characterized by non-random social preferences, crucially, only when individuals were familiar with one another suggesting social recognition is important in young sharks of this species. Genetic analyses of parent and offspring DNA revealed very high levels of multiple paternity in this species, likely due to male sexual harassment and multiple mating, which leads to increased genetic diversity between juvenile sharks. Perhaps unsurprisingly, there was no evidence of kin relatedness structuring social interactions between conspecifics. Furthermore, testing the effects of environment on social behaviour provided evidence that these juveniles aggregated more in structurally complex environments than simple ones. However, at the individual level sharks showed consistency in their social network positions through time and across different habitat types. This result is indicative of personality traits in S. canicula. Using data gathered via passive acoustic telemetry of wild shark behaviour, network analysis provided a useful tool with which to quantify movement between receivers. One chapter has been dedicated to the application of these methods, highlighting a number of different analyses for predicting movement behaviour from such data. Finally, these methods were adopted to address ecological questions in this sexually segregated species. Persistent site fidelity to a localised inshore area by both male and female sharks suggested that segregation occurred at a relatively small spatial and temporal scale. Despite strong evidence of segregation, analyses of movement networks and individual co-occurrences revealed distinct periods of behavioural synchronicity during the months of March, April and May. In addition, habitat complexity appeared to be a significant driver of female behavioural strategy. Enhancing our knowledge of the social and environmental drivers of aggregation and movement in sharks is of great importance given the ecological threat facing many of our ocean’s top elasmobranch predators.Fisheries Society of the British Isle

Integrating Ecohydraulics in River Restoration: Advances in Science and Applications

Rivers have been intensively degraded due to increasing anthropogenic impacts from a growing population in a continuously developing world. Accordingly, most rivers suffer from pressures as a result of increasing dam and weir construction, habitat degradation, flow regulation, water pollution/abstraction, and the spread of invasive species. Science-based knowledge regarding solutions to counteract the effects of river degradation, and melding principles of aquatic ecology and engineering hydraulics, is thus urgently needed to guide present and future river restoration actions. This Special Issue gathers a coherent set of studies from different geographic contexts, on fundamental and applied research regarding the integration of ecohydraulics in river restoration, ranging from field studies to laboratory experiments that can be applied to real-world challenges. It contains 13 original papers covering ecohydraulic issues such as river restoration technologies, sustainable hydropower, fish passage designs and operational criteria, and habitat modeling. All papers were reviewed by international experts in ecology, hydraulics, aquatic biology, engineering, geomorphology, and hydrology. The papers herein well represent the wide applicability of ecohydraulics in river restoration and serve as a basis to improve current knowledge and management and to reduce arguments between different interests and opinions

The ecology of ray species in an urbanised estuary: seasonality, habitat use and pollutant exposure in Tauranga Harbour.

Information about the movement, seasonality, and use of habitats by marine animals is vital for the mitigation of potential anthropogenic impacts. Ray species may be particularly at risk as they regularly inhabit coastal and estuarine waters. In New Zealand to-date, there has been scant research on the ecology of native ray species in estuarine habitats. In particular, there is a dearth of knowledge pertaining to the spatio-temporal use of the range of habitats within estuaries. The research detailed in this thesis was aimed at addressing the shortfall of information. First, a review of the methodology utilised in ascertaining movement behaviour in non-shark-like batoid elasmobranch species was carried out, as optimisation of tagging research technique underpins the ability to track behaviour of these organisms for long periods. Most studies reviewed adopted tag anchor techniques used on teleost fishes or sharks. As a consequence, the quality of information pertaining to ray habitat use and movements was, in many circumstances, poor. Synthesis of tag longevity using differing anchor methods and field and aquarium longevity experiments led to a recommendation of nylon umbrella darts for soft-skinned non-shark-like rays such as Bathytoshia brevicaudata. Second, seasonality in habitat use within the Tauranga Harbour system was examined using monthly counts of the feeding excavations of Myliobatis tenuicaudatus. This study expanded previous estimations of seasonality and feeding habitat choice in estuaries. It determined that temperature-mediated sinusoidal seasonal patterns in feeding behaviour over a period of 24 months, differed in magnitude and peak month across a range of spatial scales. This could suggest some form of sequential habitat use. Unlike previous studies, evidence of ray feeding was found year-round. This behavioural pattern has implications for calculations of sediment turnover and transport. Peak turnover estimates of ray origin from this study doubled previous estimated calculations. In addition, infaunal prey density, and locational aspects of estuary ‘sub-habitats’ characterised as various ‘zones’ as compared to ‘harbour basin’ habitats, were all found to be influential in the prediction of M. tenuicaudatus feeding activity. There were inverse seasonal differences in the relationship between densities of large infaunal bivalves (putative prey items) and ray feeding activity, suggesting that during some periods, other prey types (soft bodied organisms) may also be important. Suggestions are made that perceived predator risk and human disturbance may have a role in driving habitat preferences in addition to prey density. This study also found that natural mangrove fringe is preferred by M. tenuicaudatus for feeding habitat over areas of ‘fringe’ that had been trimmed to prevent mangrove spread. The implications of this are significant as there is a reduction in ideal feeding habitat with ongoing mangrove trimming regimes. Finally, quantification of metal body burden of M. tenuicaudatus identified low levels of some heavy metals in rays from Tauranga Harbour when compared to Porirua Harbour, and that metals in rays from the outer coast of the Bay of Plenty region were likely to be of volcanic origin. Significantly different metal assemblages of estuarine and offshore animals combined with feeding evidence found year-round in Tauranga Harbour, suggests a separation in populations between these areas. Overall however, it is clear that metal content in Tauranga Harbour rays lies below FZANZ levels of concern and the harbour may be classified as relatively unpolluted. However, the behavioural patterns of rays clearly lead them away from shallower sub estuary areas, that are known to be more contaminated by anthropogenic activity. In conclusion, this thesis provides previously unknown information about the habits and ecology of the important estuarine mesopredator M. tenuicaudatus in the context of anthropogenic risk associated with an urbanised harbour ecosystem. The information will allow informed management of harbour activities and developmental options with regard to conservation of an ecologically important species

Short duration reservoir-release impacts on impounded upland rivers

The increasing number and scale of river impoundments throughout the 19th and 20th centuries means that the management of these impoundments is crucial to the future of global riverine biota. Impoundments such as reservoirs can affect rivers in a variety of ways, not least through the reduction in amplitude of the natural hydrograph, depriving rivers of ecologically important spate flows. Many reservoir operators conduct regular safety tests, known as scour releases, during which large quantities of impounded water are released directly into rivers. This project assesses the impact of these releases on the hydrology and physio-chemistry of the receiving water bodies as well as upon fish movements and benthic macroinvertebrate abundance and diversity downstream of the reservoirs. The potential of such releases to mimic natural spate flows for ecological gain is also examined. The work took place in the Yorkshire Water catchment area in northern England between 2007 and 2010. Passive Integrated Transponder (PIT) telemetry was used to assess the responses of brown trout Salmo trutta to these short-duration releases. Tagged fish were able to maintain position during the releases and showed no evidence of wash-out or upstream migratory movements associated with the releases. Changes to macroinvertebrate abundance, diversity and community structure associated with the release were also examined. Some sites showed significant wash-out and community change following the releases while other sites were unchanged. Communities at impacted sites returned to pre-release structures within weeks of the releases. Analysis of habitat use and characteristics suggest the responses of fish and macroinvertebrates to these reservoir releases were linked to habitat heterogeneity and the use of flow refugia. The negative impacts associated with the scour releases were minimal, while mimicked spate releases may improve salmonid spawning habitat and could re-introduce valuable flow variability to impounded catchments

Southern Plains hunter-gatherer adaptations during the Late Archaic: A study in optimal foraging.

In this study, optimal foraging theory is used to evaluate hunting and butchering practices as well as the residence patterns of Late Archaic hunter-gatherers from the southern Plains. Their behavior is represented in the archaeological record by sites, features, and artifacts. Prior to exploring the data, the tenants of optimal foraging theory and central-place foraging, are presented. The first aspect of central-place foraging is that a group will venture from a home base to acquire resources. The second aspect of the theory states that special task groups are used to acquire the said resources. Once located, the resources were returned to the base. In order to better explain the task group aspect of the equation, the group foraging size theorem is employed. The theorem states that the task group's success is contingent on the appropriate number of individuals being available coupled with the appropriate resource placement on the landscape. To check the validity of this argument, two test implications are formulated using the above theoretical constructs. Test #1 is used for Beaver Dam (reliance on a home base) whereas Test #2 is applied to L. E. Certain (employment of a resource encounter and exploitation site). Initially, I set forth the expectations. Then, utilizing the evidence found at the sites, the implications are discussed. Beaver Dam, the base camp, is discussed first since this is where forays into the surrounding biomes originate. This discussion is followed by an assessment of L. E. Certain, a special extractive camp. The data revealed that Late Archaic groups maximized net energy intake while reducing energy expenditure by using a base of operation, that base being situated in an area where multiple resources were gathered just a short distance from camp. When a resource was abundant and some distance from camp, the strategy was to harvest the resource using a specially qualified group. In this study, the groups were bison hunting taskforces. These hunters embarked on their mission with a set of highly specialized stone tools to kill and process the game. The bison meat was procured utilizing butchering techniques that produced large amounts of meat and other byproducts quickly. While some of the meat was eaten on-site, most was dried and returned to camp. That this response was successful is indicated by the fact that large-scale bison kills were conducted at the L. E. Certain site for over 500 years

Linking Welfare and Quality of Scientific Output in Cynomolgus Macaques (Macaca fascicularis) used for Regulatory Toxicology

Cynomolgus macaques (Macaca fascicularis) are the most commonly used non-human primate for research and testing in Europe. Their principal use is in preclinical safety testing of new pharmaceuticals to assess risk of adverse effects, as indicated by changes in a core battery of physiological measures before human exposure. Regulatory studies are strictly controlled through legislation and codes of practices underpinned by the principles of humane science, the 3Rs; Replacement, Reduction and Refinement. Despite the link between good welfare and good science now universally made in codes of practice, legislation and the literature, there are few studies aimed at systematically examining the link and almost no quantitative data from cynomolgus macaques used for toxicology. The main aim of this thesis was to examine the link between Refinement, animal welfare and scientific output for this important animal model, piggy-backing on regulatory studies conducted by a large contract research organisation. In the laboratory, animal welfare is formally considered in terms of Refinement which has evolved to include both the reduction of negative welfare states and the proactive enhancement of positive welfare over the animal’s lifetime. A multidisciplinary approach to welfare assessment including measures of behaviour, physiology and physical health, and which built upon current unit procedures was undertaken to produce an overall assessment of welfare in cynomolgus macaques. Macaque facial expressions, vocalisations, activity and position in the home cage, body weight change, body condition and alopecia scores were found to be reliable indicators of welfare state and would be most feasible for care staff to monitor. The concept of quality of scientific output was defined in relation to toxicological findings and includes sensitivity, reliability and repeatability of individual measures in the core battery (e.g. heart rate, blood pressure, haematology, clinical chemistry and organ weights). The link between welfare and quality of scientific output was then systematically explored with Refinements to macaque use in regulatory studies. The first, a data mining study, undertaken to quantify the effects on biological data recorded from cynomolgus macaques, used in regulatory studies over an eight-year period as the CASE sponsor transitioned from single to permanent group housing, found the effects to be highly variable on individual parameters in the core battery and in some instances welfare-positive effects of group housing were confounded by concurrent changes in standard operating procedures. A further study of planned Refinements to macaque-care staff interaction through enhanced socialisation was found to help animals cope better with husbandry and scientific procedures and enhance quality of cardiovascular measures recorded at baseline. In light of these findings a number of recommendations are made including a framework of terms useful for measuring quality of scientific output, a welfare assessment framework and Refinements to husbandry and scientific procedures for cynomolgus macaques used in regulatory toxicology. Because of their capacity to suffer it is both ethically and scientifically important that macaque welfare is maximised and their use results in valid and reliable experimental outcomes informing on the safety and efficacy of new pharmaceuticals prior to human exposure