title: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2014

authors: Hicks, Brendan J.

abstract: The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (eels, goldfish, and koura). In the current study, we present the findings from the eighth year of sampling (2014) and a summary of previous surveys.
We used the University of Waikato’s 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of 642 fish (11.3 kg) 11 sites on 9 December 2014, which comprised 2,914 lineal m and 11,656 m² in area. Koura and 4 fish species were present, with common bully most abundant (up to 27 fish 100 m⁻² at the site 5, edge habitat). Goldfish (up to 5.92 g m⁻²) was the next most abundant species, and was most abundant in sites 8-11 the lower channel, especially at site 11, the excavated side channel. Rainbow trout were next the most abundant species (up to 0.25 fish 100 m⁻² ). Mean bully biomass (5.25 g m⁻²) was much higher than for smelt (0.07 g m⁻²). Koura had a patchy distribution; 5 individuals were caught.
Comparing catches over the 8 years of sampling, the abundance of common bullies in 2014 (4.81 fish 100 m⁻²) was consistent with catch rates in most post-wall years (after 2007; range 0.81-5.72 fish 100 m⁻²), but lower than in 2013. The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, suggesting that bully density estimates might decrease with decreasing BDD. However, common bully densities in 2012 and 2011 were inversely related BDD. In 2014, catches of smelt, a similar sized fish to bullies, were extremely low.
Goldfish biomass increased initially 2009 and 2010 because of targeted fishing in the excavated side channel (site 11), which has dense macrophyte beds that provide good habitat for goldfish. The continued rise in goldfish density from 2012 on suggests a real increase in goldfish numbers has occurred. Eels were scarce in the Ohau Channel and catches were very variable. Longfin eels were caught in most years, and in 2012 and 2013 shortfin eels were also caught, but in 2014 no eels were caught.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 7 years of post-wall data, and comparison of means and standard deviations suggest that the number of bullies has decreased.
An intriguing trend of decreasing rainbow trout densities with increasing BDD, which is a measure of both water clarity and phytoplankton abundance, has occurred following wall construction (Figure 3). The trend is opposite to the usual decline of catch rate by boat electrofishing with reduced water clarity. The explanation for this is not immediately clear, and could be increased avoidance of the electrofishing boat by trout in clearer water. It is also possible that reduced BDD indicates high algal productivity in Lake Rotorua, which in turn could increase trout abundance in the Ohau Channel. This remains to be tested

text: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2014 The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (eels, goldfish, and koura). In the current study, we present the findings from the eighth year of sampling (2014) and a summary of previous surveys.
We used the University of Waikato’s 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of 642 fish (11.3 kg) 11 sites on 9 December 2014, which comprised 2,914 lineal m and 11,656 m² in area. Koura and 4 fish species were present, with common bully most abundant (up to 27 fish 100 m⁻² at the site 5, edge habitat). Goldfish (up to 5.92 g m⁻²) was the next most abundant species, and was most abundant in sites 8-11 the lower channel, especially at site 11, the excavated side channel. Rainbow trout were next the most abundant species (up to 0.25 fish 100 m⁻² ). Mean bully biomass (5.25 g m⁻²) was much higher than for smelt (0.07 g m⁻²). Koura had a patchy distribution; 5 individuals were caught.
Comparing catches over the 8 years of sampling, the abundance of common bullies in 2014 (4.81 fish 100 m⁻²) was consistent with catch rates in most post-wall years (after 2007; range 0.81-5.72 fish 100 m⁻²), but lower than in 2013. The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, suggesting that bully density estimates might decrease with decreasing BDD. However, common bully densities in 2012 and 2011 were inversely related BDD. In 2014, catches of smelt, a similar sized fish to bullies, were extremely low.
Goldfish biomass increased initially 2009 and 2010 because of targeted fishing in the excavated side channel (site 11), which has dense macrophyte beds that provide good habitat for goldfish. The continued rise in goldfish density from 2012 on suggests a real increase in goldfish numbers has occurred. Eels were scarce in the Ohau Channel and catches were very variable. Longfin eels were caught in most years, and in 2012 and 2013 shortfin eels were also caught, but in 2014 no eels were caught.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 7 years of post-wall data, and comparison of means and standard deviations suggest that the number of bullies has decreased.
An intriguing trend of decreasing rainbow trout densities with increasing BDD, which is a measure of both water clarity and phytoplankton abundance, has occurred following wall construction (Figure 3). The trend is opposite to the usual decline of catch rate by boat electrofishing with reduced water clarity. The explanation for this is not immediately clear, and could be increased avoidance of the electrofishing boat by trout in clearer water. It is also possible that reduced BDD indicates high algal productivity in Lake Rotorua, which in turn could increase trout abundance in the Ohau Channel. This remains to be tested

year: 2015

title: Tangi and State Funeral: Te Arikinui Dame Te Atairangikaahu and Prime Minister Norman Kirk

authors: McRae, Karyn Okeroa

subjects: Tangi

abstract: The tangi of Te Arikinui Dame Te Atairangikaahu (Te Arikinui) in 2006 paralleled the State funerals for New Zealand Prime Ministers like Norman Kirk who died in 1974. State funerals require the huge mobilization of people and resources and always attract the attention of the national and international media. The death of a Prime Minister is news worthy, but what of a minority indigenous fourth world leader like Te Arikinui? Why did her passing attract so much media attention? In this study I argue that media representation of the tangi of Te Arikinui was largely about social, cultural and symbolic capital. In media saturated societies such as Aotearoa/New Zealand, through mainstream media outlets like TV One News and the Waikato Times, Te Arikinui’s tangi event claimed a dominant space in the lives of Maori and non Maori alike. The data source includes print news media coverage of the tangi of Te Arikinui and the State funeral of Norman Kirk. Descriptive narrative and abductive analysis inform the methodology used in this study. As expected, print media reporting of both events progressed through the three stages identified by Durkheim, those of, separation, liminality and reincorporation. The ownership of death, the deceased and the continued possession of their mortal remains, itself a cultural object with symbolic and cultural capital, reflected the actual power and control of the possessor. State funerals and tangi are about the ritualized performance of grief and mourning, and require the appropriate social, cultural and symbolic capital for its enactment.

text: Tangi and State Funeral: Te Arikinui Dame Te Atairangikaahu and Prime Minister Norman Kirk The tangi of Te Arikinui Dame Te Atairangikaahu (Te Arikinui) in 2006 paralleled the State funerals for New Zealand Prime Ministers like Norman Kirk who died in 1974. State funerals require the huge mobilization of people and resources and always attract the attention of the national and international media. The death of a Prime Minister is news worthy, but what of a minority indigenous fourth world leader like Te Arikinui? Why did her passing attract so much media attention? In this study I argue that media representation of the tangi of Te Arikinui was largely about social, cultural and symbolic capital. In media saturated societies such as Aotearoa/New Zealand, through mainstream media outlets like TV One News and the Waikato Times, Te Arikinui’s tangi event claimed a dominant space in the lives of Maori and non Maori alike. The data source includes print news media coverage of the tangi of Te Arikinui and the State funeral of Norman Kirk. Descriptive narrative and abductive analysis inform the methodology used in this study. As expected, print media reporting of both events progressed through the three stages identified by Durkheim, those of, separation, liminality and reincorporation. The ownership of death, the deceased and the continued possession of their mortal remains, itself a cultural object with symbolic and cultural capital, reflected the actual power and control of the possessor. State funerals and tangi are about the ritualized performance of grief and mourning, and require the appropriate social, cultural and symbolic capital for its enactment.

year: 2010

title: Tracking battery state-of-charge in a continuous use off-grid electricity system

authors: Apperley, Mark

subjects: state-of-charge

abstract: The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery's remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naive and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

text: Tracking battery state-of-charge in a continuous use off-grid electricity system The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery's remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naive and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

year: 2014