Boat electrofishing survey of common smelt and common bullies in the Ohau Channel

We conducted a boat electrofishing survey of the Ohau Channel, which flows from Lake Rotorua to Lake Rotoiti, on 13 December 2007. The purpose of the survey was to investigate the longitudinal pattern in densities of common smelt (Retropinna retropinna) and common bullies (Gobiomorphus cotidianus) along the Ohau Channel. We caught 1,267 fish comprising three native fish species and two introduced fish species in 1.58 km of fished distance at a total of 10 sites. Native species caught were the common smelt, common bully and longfinned eel (Anguilla dieffenbachii) and introduced species were rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus). Assuming that the bow-mounted anodes effectively fished a 4 m swath then the total area fished was 6,328 m2 (0.632 ha). Common smelt densities varied among the 10 different sites in the Ohau Channel ranging from 0 to 10.6 fish 100 m-2. Smelt density was higher at the upstream end of the channel near the weir at the Lake Rotorua outlet, decreasing with increasing distance from the weir. Smelt were found in the littoral zones but were not caught in mid-channel habitats. In the upstream reaches of the Ohau Channel, directly below the weir, a high number of juveniles (4.4 fish 100 m-2) were captured compared to the amount of juveniles captured at the other sites (0 – 1.2 fish 100 m-2). Common bully densities varied among the 10 different sites in the Ohau Channel ranging from 0.2 to 58.3 fish 100 m-2. No longitudinal pattern in the distribution of common bullies was evident along the channel. The highest densities were found halfway along the Ohau Channel where there was an abundance of dense macrophyte beds. Common bully densities were found to be much higher in the edge habitats with macrophyte beds compared to the mid-channel habitats and the willow edge habitat where there were relatively low densities. Size frequency data shows that there is generally a higher proportion of small bullies than larger ones suggesting that recruitment is occurring. Both adult and juvenile rainbow trout were observed in the Ohau Channel. Most of these individuals were found in the upstream section of the channel below the weir and ranged from a 75 mm juvenile to a fully grown adult about 500 mm long. Large longfinned eels were also captured and were only found in the downstream section of the Ohau Channel in willow-dominated edges. In the bottom third section of the channel, near the possible artificial embayment, goldfish were present

Storage Under Backwardation: A Direct Test of the Wright-Williams Conjecture

Commodities are often stored when the spot price exceeds the future price in a central market. Wright and Williams conjectured that inventories are held in locations far from the central market on these occasions. In these locations the spot price is lower than the price for forward delivery because transport costs are temporarily high. This hypothesis has not been directly tested, because prices for forward delivery are not normally available at non-central locations. This paper uses an example where these prices exist to test the hypothesis. The evidence, from the late nineteenth century corn markets in Chicago and New York, strongly supports the conjecture. Length: 30 pagesInventories, commodity prices, transport costs

Analysis of Chinese travel blogs of New Zealand

The Chinese outbound tourism market is a fast growing source market for many destinations. However, more research is needed to better understand the Chinese outbound tourism market and its diversity and complexity. Again, it can be argued that consistent monitoring of what is a fast evolving market is required, even where prior research has been undertaken. The aim of this research is to provide the tourism industry with a better understanding of the Chinese tourist market and the attitudes of Chinese visitors with specific reference to New Zealand. Consequently perceived destination image, travel motivations, and patterns of online communications of and about New Zealand were identified by analysing travel blogs written by Chinese tourists. Given that there were 181 million bloggers existing in China by the end of 2009 (CNNIC, 2009), blogs written by Chinese visitors have a significant market value for tourism organisations and marketers. This study used content analysis to identify the perceived destination image held by Chinese tourists to New Zealand. In this study, the analytical process was divided into two parts, namely photographic and textual analysis. In each of the two parts, qualitative content analysis was first undertaken, and then followed by secondary quantitative analysis to support the findings discerned through the qualitative process. By analysing 6968 photographs and 408 blog entries posted by Chinese visitors, an image of New Zealand as a tourism destination was identified. The findings revealed that the main components of New Zealand, as perceived by Chinese visitors, were that it possessed a protected ecological environment, offered a variety of activities, and had a highly developed society with a “Pakeha” culture. The research also indicated that Chinese cultural norms played an important role in the process of decision making, perception formation and interpretation. These norms included the desire of harmony, Li, Junzi Aspiration, and a respect of authorities. The results of the study also included details about travel patterns in dining, accommodation, and tourism activities. These results indicated that content analysis of visual and textual materials provides rich information about perceived destination image, travel preference, and online information search behaviours. Online photographs and narratives posted by visitors are not only valuable information source for potential visitors who read the blogs, but can also be an effective way to understand the Chinese market. Based on the results, it can be concluded that blogs are important, and point a way by which destination marketing organisations can seek to influence potential visitors. For example, blog celebrities are an effective way by which to attract thousands of readers to know more about the country. The use of the Chinese language and creating special arrangements for Chinese festivals are shown to be effective means by which hosts can display a friendly attitude to their Chinese guests. With more and more countries being granted Approved Destination Status (ADS) by the Chinese government, Chinese citizens have more choices as to where to travel overseas, thereby intensifying competition for their custom. It is vital for tourism destinations to promote their unique features through all possible channels according to different target markets. Additionally, because service quality is a crucial issue for group tourists, consistent monitoring the travel blogs is an effective way of facilitating the improvement of the service quality of tourism product suppliers

Ecology of common bully (Gobiomorphus cotidianus) in the Tarawera and Rangitaiki rivers: isolation by inland distance or anthropogenic discharge?

Previous research has identified distinct genetic, life-history and reproductive differences between populations of common bully (Gobiomorphus cotidianus) upstream and downstream of a pulp and paper mill outfall on the Tarawera River in the Bay of Plenty, New Zealand. This study investigated the distribution of common bully in the Tarawera River by examining fish collected from upstream (37 km inland) and downstream (20 km inland) locations and comparing them to fish from similar inland locations (40 km and 17 km inland, respectively) in the nearby Rangitaiki River. Reproductive divergence was observed between upstream and downstream sites of both rivers by differing annual trends in gonadosomatic index. Stable carbon and nitrogen isotopes confirmed residency at each sampling site and otolith microchemistry demonstrated different life-history strategies between upstream and downstream populations. Diadromous recruits dominated in both downstream river populations, with a general disappearance of diadromy upstream. A mixture of diadromous and non-diadromous fish were found in the upstream Rangitaiki River, whereas diadromous recruits were absent in the upstream Tarawera River. A reduction in oculoscapular canal structures also coincided with loss of diadromy in fish from both rivers. A behavioural study to determine whether pulp and paper mill effluent may deter fish migration within the Tarawera River demonstrated a strong avoidance of effluent, but only at concentrations (>25%) greater than those that naturally occur in the river (<15%). The results of this study suggest that combinations of influences coupled with inland distance are likely to be responsible for the isolation of common bully subpopulations within the Tarawera River

A review of restorative justice responses to offending

Restorative justice has been enthusiastically embraced in many justice systems as an alternative to incarceration for young adult and Indigenous offenders. But how well does it work? Abstract The present review sought to determine on the available evidence (a) whether restorative justice (RJ) is an effective means of reducing re-offending, (b) what benefits victims of crime obtain from participation in the RJ process, (c) whether the public supports the principles of RJ, and (d) how the cost and efficiency of RJ proceedings compare with conventional courts in cost and efficiency (i.e. time taken to finalize cases). The review finds little reliable evidence that RJ reduces re-offending. Victims who participate in RJ are generally satisfied with the experience but it is unclear whether they are more satisfied than victims in similar cases that are dealt with in court. The limited evidence available suggests that the public supports the principles of RJ. It appears to be a less expensive and more efficient way of finalizing criminal cases involving young people but, once again, the evidence on this issue at this stage is rather limited. Evidence Base, issue 1, 201

Source-tracking cadmium in New Zealand agricultural soils: a stable isotope approach

Cadmium (Cd) is a toxic heavy metal, which is accumulated by plants and animals and therefore enters the human food chain. In New Zealand (NZ), where Cd mainly originates from the application of phosphate fertilisers, stable isotopes can be used to trace the fate of Cd in soils and potentially the wider environment due to the limited number of sources in this setting. Prior to 1997, extraneous Cd added to soils in P fertilisers was essentially limited to a single source, the small pacific island of Nauru. Analysis of Cd isotope ratios (ɛ114/110Cd) in Nauru rock phosphate, pre-1997 superphosphate fertilisers, and Canterbury (Lismore Stony Silt Loam) topsoils (Winchmore Research Farm) has demonstrated their close similarity with respect to ɛ114/110Cd. We report a consistent ɛ114/110Cd signature in fertiliser-derived Cd throughout the latter twentieth century. This finding is useful because it allows the application of mixing models to determine the proportions of fertiliser-derived Cd in the wider environment. We believe this approach has good potential because we also found the ɛ114/110Cd in fertilisers to be distinct from unfertilised Canterbury subsoils. In our analysis of the Winchmore topsoil series (1949-2015), the ɛ114/110Cd remained quite constant following the change from Nauru to other rock phosphate sources in 1997, despite a corresponding shift in fertiliser ɛ114/110Cd at this time. We can conclude that to the present day, the Cd in topsoil at Winchmore still mainly originates from historical phosphate fertilisers. One implication of this finding is that the current applications of P fertiliser are not resulting in further Cd accumulation. We aim to continue our research into Cd fate, mobility and transformations in the NZ environment by applying Cd isotopes in soils and aquatic environments across the country

The Mirror MMDBMS architecture

Handling large collections of digitized multimedia data, usually referred to as multimedia digital libraries, is a major challenge for information technology. The Mirror DBMS is a research database system that is developed to better understand the kind of data management that is required in the context of multimedia digital libraries (see also URL http://www.cs.utwente.nl/~arjen/mmdb.html). Its main features are an integrated approach to both content management and (traditional) structured data management, and the implementation of an extensible object-oriented logical data model on a binary relational physical data model. The focus of this work is aimed at design for scalability

Experimental and numerical study of time-dependent behaviour of reinforced self-compacting concrete slabs

University of Technology, Sydney. Faculty of Engineering and Information Technology.Developments in concrete technology provide engineers, designers, suppliers and contractors with new methods of approaching engineering problems. Many of these developments are engineered solutions to technical and commercial problems, by either improving the current practices or overcoming limitations in the existing technology. One of the developments is Self-Compacting Concrete (SCC). SCC refers to a ‘highly flowable, non-segregating concrete that can be spread into place, fill the formwork, and encapsulate the reinforcement without the aid of any mechanical consolidation’ as defined by the American Concrete Institute (ACI). SCC is regarded as one of the most promising developments in concrete technology due to significant advantages over Conventional Concrete (CC). Many different factors can influence a decision to adopt SCC over CC ranging from structural performance to associated costs. These decisions should be well informed and based on a sound understanding of such factors. In addition, Fibre Reinforced Self-Compacting Concrete (FRSCC) is a relatively new composite material which congregates the benefits of the SCC technology with the profits derived from the fibre addition to a brittle cementitious matrix. Fibres improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. For a structure (made by CC, SCC and FRSCC) to remain serviceable, crack widths must be small enough to be acceptable from an aesthetic point of view, to avoid waterproofing and deterioration problems by preventing the ingress of water and harmful substances. Crack control is therefore an important aspect of the design of reinforced concrete structures at the serviceability limit state. Limited researches have been undertaken to understand cracking and crack control of SCC and FRSCC members. Since, the time-dependent mechanisms of SCC and FRSCC are still not completely understood; a reliable and universally accepted design procedure for cracking and crack control SCC and FRSCC members has not been developed yet. There exists a need for both theoretical and experimental research to study the critical factors which affect the time-dependant crack of SCC and FRSCC members. In this study cracking caused by external loads in reinforced SCC and FRSCC slabs is examined experimentally and analytically. The mechanisms associated with the flexural cracking due to the combined effects of constant sustained service loads and shrinkage are observed. One of the primary objectives of this study is to develop analytical models that accurately predict the hardened mechanical properties of SCC and FRSCC. Subsequently, these models have been successfully applied to simulate time-dependent cracking of SCC and FRSCC one-way slabs. Series of tests on eight prismatic, singly reinforced concrete one-way slabs subjected to monotonically increasing loads or to constant sustained service loads for up to 240 days, were conducted. An analytical model is presented to simulate instantaneous and time-dependant flexural cracking of SCC and FRSCC members. It should be emphasized that any analytical model developed for calculation of crack width and crack spacing of reinforced SCC and FRSCC slabs must be calibrated by experimental data and verified by utilizing Finite Element Method (FEM). The analytical predictions of crack width and crack spacing for the SCC and FRSCC one way slabs are in reasonably good agreement with the experimental observations

Variability in nutrient loading to lake ecosystems and associated impacts on water quality

Globally, the accelerated eutrophication of lake ecosystems due to excess inputs of nitrogen (N) and phosphorus (P) is a significant problem. The rate of loading of N and P to lakes varies both in space and time; consequently, developing good understanding of such spatial and temporal variability is critical for developing integrated approaches to managing lake water quality. This study aimed to improve understanding of spatial and temporal variations in N and P loading to lakes, and, to examine how this variability affects water quality. The topic was considered at global, national and catchment scales. Analysis of an extensive global dataset was undertaken to examine relationships between N, P and chlorophyll a (chl a) in lakes along a gradient of latitude inclusive of tropical, temperate and polar regions. The ratio of total nitrogen (TN) to total phosphorus (TP) was positively correlated with latitude, reflecting global–scale variation in nutrient cycling processes and/or nutrient sources. Relative to temperate lakes, the statistical capability of concentrations of TN and TP to predict chl a concentration (i.e. indicating bottom–up control by nutrients) was shown to be poor for both tropical and polar lakes. These differences reflected latitudinal variation in lake ecosystem functioning, and highlighted the potential unsuitability of applying relationships derived for temperate lakes elsewhere. Quantile regression was used to derive theoretical chl a near–maxima as a function of either TN or TP concentrations. Consequently, chl a:TN and chl a:TP yields (by mass) of 0.046:1 and 0.87:1 were determined to approximate the maximum possible yields of chl a under optimal conditions as a proxy for phytoplankton biomass potential. Nationally–significant relationships between landscape characteristics and in–lake TN and TP concentrations were quantified for a representative sample of 101 lakes in New Zealand. Geographical Information Systems were used to analyse data from a range of sources that related to both lake–specific and wider landscape characteristics. Inferential statistical methods were then used to quantify relationships between in–lake nutrients and both land use and naturally–occurring soil P. National–scale variability in mean catchment soil P was found to be unrelated to in–lake TP concentrations, reflecting the dominant influence of human–related sources of P on TP concentrations in New Zealand lakes. The extent of intensive pastoral agriculture was the best land use predictor of TN and TP concentrations, accounting for 38.6% and 41.0% of variation respectively. Exotic forestry accounted for a further 18.8% of variation in TP concentrations. A sub–sample of lakes for which intensive pastoral agriculture was the dominant catchment land use was then considered to test hypotheses regarding potential interactive effects of eight landscape characteristics on the positive relationship between intensively managed pasture and in–lake nutrient concentrations. Both maximum lake depth and the ratio of catchment to lake area had significant interactive effects, exerting a negative and a positive influence, respectively. In addition, an indicator of hydrological connectivity (lake order) also had a positive interactive effect on the relationship between this land use type and in lake TP (but not TN) concentrations. To examine these broad relationships at finer spatial resolution, and also to quantify temporal variations in nutrient loading, an extensive field programme was conducted in the catchment of Lake Rotorua (Bay of Plenty, New Zealand); a large (80.5 km2), relatively shallow (zmean = 10.8 m) lake that has experienced eutrophication. The Ngongotaha and Puarenga streams are two major inflows to the lake that were sampled at high frequency throughout a wide range of stream discharge coinciding with rainfall events. Both streams had different catchment characteristics (e.g. land use and hydrogeomorphology) which enabled spatial variations in nutrient loading between sub–catchments located upstream of a common lake ecosystem to be examined. Streams were sampled during a total of 17 hydrological events, including three during which both streams were simultaneously sampled to compare differences in pollutant transport between the streams during similar hydrological conditions. Relationships between nutrient concentrations and stream discharge were broadly similar for the two catchments, and quantification of relationships permitted nutrient loading to be estimated continuously over annual periods. Key findings included the dominance of event loads by dissolved inorganic N and the strong positive correlation between discharge and particulate P concentrations. Quantification of hysteresis in relationships between nutrient concentrations and discharge provided information about the relative importance of near– versus far–channel sources during individual events. For example, elevated concentrations of dissolved inorganic N during recessing hydrograph limbs for the Puarenga Stream suggested diffuse delivery of N from an upstream source. Temporal inequality in estimated loading over a two–year period was high for TP as, for example, 50% of estimated cumulative two–year loads of TP were calculated to have been transported during 10–17% of the two–year time period. The effects of storm flow discharges on water quality in Lake Rotorua were studied at fine spatial and temporal resolution for a five–day period with high rainfall in summer. An intensive programme of lake and stream sampling was paired with application of a three–dimensional hydrodynamic–ecological model (ELCOM–CAEDYM) to specifically study how dynamic fluxes in water, sediment, N and P transport in the Ngongotaha Stream inflow influenced water quality and phytoplankton nutrient limitation in the transition zone present where the stream enters the lake. Wind–driven basin–scale horizontal circulations in the lake caused deflection of the inflowing stream which strongly influenced water quality in the littoral zone for a distance of up to 1 km from the stream mouth, thus highlighting the potential importance of basin–scale horizontal transport processes in mediating the effects of storm flow discharges on lake water quality. The nutrient limitation status of phytoplankton varied both spatially and temporally within the lake in relation to nutrient transport processes, emphasising the relatively fine spatial and temporal scales at which key processes that affect phytoplankton ecology can occur. Dilution of lake water by the stream inflow strongly affected the spatial distribution of chl a, although the highly spatially resolved sampling identified ‘hot spots’ within the nutrient–rich plume which contributed to fine scale (≈10–30 m) patchiness in the transition zone. The results of nutrient enrichment experiments indicated that such patchiness was consistent with a scenario of relative stimulation in the growth of lentic phytoplankton due to high nutrient availability in the spreading plume. To further examine the issue of nutrient bioavailability, chemical fractionation techniques and batch culture experiments were conducted to investigate spatial (between streams) and temporal (between periods of varying stream discharge) variations in the bioavailability of particulate P transported in storm flow for the two study streams. Bicarbonate–dithionate extraction indicated that 25–100% of particulate P transported in stream water samples collected during storm flow was potentially bioavailable if exposed to anoxia, e.g. in the lake hypolimnion during calm summer periods. Somewhat paradoxically though, bioassays indicated that, under oxic conditions in the laboratory, bioavailable P was actually higher in filtered samples (particulate P removed) than in unfiltered samples (higher TP concentrations, particulate P present). This result was attributed to net adsorption of dissolved inorganic P to the sediments present in the unfiltered treatments, and therefore highlights the importance of considering physicochemical characteristics of receiving environments when assessing bioavailability of P sorbed to sediments. Hence, by examining a range of spatial scales and integrating understanding gained using a range of research methods, this study has provided knowledge of underlying drivers of spatial and temporal variability in nutrient loading to lake ecosystems at scales ranging from global to a few metres. Furthermore, it has provided insight into how such variability can affect lake water quality. This knowledge can guide actions that are increasingly required to safeguard the services provided by lake ecosystems in a future with increasing global and local pressures on freshwaters

Age composition, growth, and reproduction of koi carp (Cyprinus carpio L.) in the lower Waikato, New Zealand

A total of 566 koi carp (Cyprinus carpio) from the lower Waikato region were aged from scales and opercular bones, and growth was modelled with the von Bertalanffy growth function. There was no difference in growth rate between male and female carp. Growth of koi carp between zero and 3 years of age was lower than that of common carp in Europe and Australia. However, after 5 years of age the growth of koi carp was higher than that of common carp in Europe, but still below that of carp in Australia. Males rarely lived in excess of 8 years, whereas females lived to 12 years. Mean total fecundity calculated from 44 running-ripe females was 299 000 oocytes (±195 600 SD) (range 29 800–771 000). Relative fecundity ranged from 19 300 to 216 000 oocytes kg–1 total body weight, with a mean of 97 200 (±35 000 SD) oocytes kg–1. Feral koi carp in the Waikato are capable of multiple spawnings within their lifetimes. Within a spawning season, Waikato populations of feral koi carp contained females that spawned once, and females that had the potential to have spawned repeatedly. Female gonadosomatic index (GSI) varied with season and was negatively related to water temperature