title: Does seagrass influence the behavioural and physiological response to flow in juvenile snapper (Pagrus auratus)?

authors: Cooper, Jordan

subjects: Seagrass habitats

abstract: Many juvenile fish species are associated with structural habitats, potentially benefiting them from reduced predation and competition as well as enhanced feeding opportunities. It is also possible that structural habitats may provide a refuge from flow. Research on juvenile snapper in New Zealand has largely focused on their habitat preference. Juvenile snapper (Pagrus auratus) have been observed in close proximity to seagrass (Zostera muelleri) in New Zealand estuaries and I tested whether this association offered a refuge from flow. In an annular flume I exposed two cohorts of juvenile snapper 4.1 ± 0.5 cm and 8.9 ± 0.7 cm in length to sequential increases of flow speed (approximately 1 body length per second every 15 minutes). Flow speed increased at 3 cm s⁻¹ every 15 minutes for the smaller cohort of juvenile snapper, and 8 cm s⁻¹ for the larger cohort of juvenile snapper. Juvenile snapper were exposed to three treatments comprising of; bare, mixed (seagrass, bare and edge habitat) and full seagrass coverage. Fish behaviour was observed and critical swimming speed (Ucrit) estimated (i.e. the flow at which fish can no longer maintain position). Juvenile snapper were exposed to flow speeds that are representative of current flows in New Zealand estuaries and harbours. A startle response was recorded at the end as an indicator of fatigue and from larger juveniles a blood sample was collected via caudal puncture to determine if there were any physiological advantages offered by seagrass, by analysing stress indicators (based on lactate, triglyceride, glucose, haemoglobin and haematocrit).

Velocity profiles indicated that the seagrass treatment and sampling points 2 (seagrass upstream and downstream) and 9 (5 cm into the leading edge of seagrass) from the mixed treatment dampened the flow speed within the annular flume. This result may be responsible for the increased percentage of time spent utilising the edge habitat as flow velocity increased, indicating that juvenile snapper seek refuge from high flows in or on the leading edge of seagrass patches. These results are consistent with an increase in critical swimming speed with increasing seagrass coverage (smaller juvenile snapper – bare = 19.47, mixed = 21.13, seagrass = 21.66 cm s⁻¹) (larger juvenile snapper – bare = 52.23, mixed = 58.89, seagrass = 60.31 cm s⁻¹). Physiological indicators, triglyceride, yielded significant differences between the bare treatment (1.40 mM) compared to the mixed (1.05 mM) and seagrass (1.01 mM) treatments, suggesting that energy stores were more readily utilised as energy expenditure increased where structural complexity was absent. The bare treatment also produced the highest values for both lactate and glucose, however, results were not significant. Mean cell haemoglobin concentration and total haemoglobin concentration did not yield significant differences between treatments. Whilst producing positive trends, results suggest that the effect of structural complexity was subtle in the annular flume. These findings have important implications for other hypotheses to explain the association between juvenile snapper and seagrass beds.

text: Does seagrass influence the behavioural and physiological response to flow in juvenile snapper (Pagrus auratus)? Many juvenile fish species are associated with structural habitats, potentially benefiting them from reduced predation and competition as well as enhanced feeding opportunities. It is also possible that structural habitats may provide a refuge from flow. Research on juvenile snapper in New Zealand has largely focused on their habitat preference. Juvenile snapper (Pagrus auratus) have been observed in close proximity to seagrass (Zostera muelleri) in New Zealand estuaries and I tested whether this association offered a refuge from flow. In an annular flume I exposed two cohorts of juvenile snapper 4.1 ± 0.5 cm and 8.9 ± 0.7 cm in length to sequential increases of flow speed (approximately 1 body length per second every 15 minutes). Flow speed increased at 3 cm s⁻¹ every 15 minutes for the smaller cohort of juvenile snapper, and 8 cm s⁻¹ for the larger cohort of juvenile snapper. Juvenile snapper were exposed to three treatments comprising of; bare, mixed (seagrass, bare and edge habitat) and full seagrass coverage. Fish behaviour was observed and critical swimming speed (Ucrit) estimated (i.e. the flow at which fish can no longer maintain position). Juvenile snapper were exposed to flow speeds that are representative of current flows in New Zealand estuaries and harbours. A startle response was recorded at the end as an indicator of fatigue and from larger juveniles a blood sample was collected via caudal puncture to determine if there were any physiological advantages offered by seagrass, by analysing stress indicators (based on lactate, triglyceride, glucose, haemoglobin and haematocrit).

Velocity profiles indicated that the seagrass treatment and sampling points 2 (seagrass upstream and downstream) and 9 (5 cm into the leading edge of seagrass) from the mixed treatment dampened the flow speed within the annular flume. This result may be responsible for the increased percentage of time spent utilising the edge habitat as flow velocity increased, indicating that juvenile snapper seek refuge from high flows in or on the leading edge of seagrass patches. These results are consistent with an increase in critical swimming speed with increasing seagrass coverage (smaller juvenile snapper – bare = 19.47, mixed = 21.13, seagrass = 21.66 cm s⁻¹) (larger juvenile snapper – bare = 52.23, mixed = 58.89, seagrass = 60.31 cm s⁻¹). Physiological indicators, triglyceride, yielded significant differences between the bare treatment (1.40 mM) compared to the mixed (1.05 mM) and seagrass (1.01 mM) treatments, suggesting that energy stores were more readily utilised as energy expenditure increased where structural complexity was absent. The bare treatment also produced the highest values for both lactate and glucose, however, results were not significant. Mean cell haemoglobin concentration and total haemoglobin concentration did not yield significant differences between treatments. Whilst producing positive trends, results suggest that the effect of structural complexity was subtle in the annular flume. These findings have important implications for other hypotheses to explain the association between juvenile snapper and seagrass beds.

year: 2015

title: Marriage Policy in the Philippines:  A Case Study in Agenda Setting

authors: Guzman, Emmanuel Avila

subjects: marriage policy

abstract: This thesis asks why there is no legal provision for divorce in the Philippines despite obvious public interest in change in this area of policy. It draws on the public policy theories of Sabatier (1988), Kingdon (1995) and Lukes (1974) in seeking to understand this situation. In so doing it gives attention to questions about the influence of relevant policy actors, the core belief systems behind competing policy positions, the relation of the Catholic Church in this policy issue, the power of the Church compared with groups advocating for the re-establishment of divorce, and the implications of this for the prevailing policy. Law reform initiatives to re-establish divorce have been kept off the government agenda as a consequence of the sustained exercise of influence by the Catholic Church on the government. This often hidden and indirect exercise of power has organized the divorce issue out of politics in the Philippines.  The lessons drawn here provide a deeper understanding of why some issues and not others come to be issues that are given attention by governments.

text: Marriage Policy in the Philippines:  A Case Study in Agenda Setting This thesis asks why there is no legal provision for divorce in the Philippines despite obvious public interest in change in this area of policy. It draws on the public policy theories of Sabatier (1988), Kingdon (1995) and Lukes (1974) in seeking to understand this situation. In so doing it gives attention to questions about the influence of relevant policy actors, the core belief systems behind competing policy positions, the relation of the Catholic Church in this policy issue, the power of the Church compared with groups advocating for the re-establishment of divorce, and the implications of this for the prevailing policy. Law reform initiatives to re-establish divorce have been kept off the government agenda as a consequence of the sustained exercise of influence by the Catholic Church on the government. This often hidden and indirect exercise of power has organized the divorce issue out of politics in the Philippines.  The lessons drawn here provide a deeper understanding of why some issues and not others come to be issues that are given attention by governments.

year: 2009

title: 'Making its own history': New Zealand historical fiction for children,1862-2008

authors: Clark, Louise Henriette

subjects: children's literature

abstract: This thesis considers historical fiction for children and young people dealing with New Zealand history from the arrival of the first Polynesian settlers to the end of the nineteenth century.  It provides both a comprehensive survey of historical novels published between 1862 and the end of 2008, and an analysis of the way the same historical events and periods have been depicted in historical novels written at different times.  Individual chapters discuss books set during specific historical periods or dealing with particular events - the pre-European period, early contact, nineteenth century immigration, the New Zealand Wars, the gold rushes, and the colonial period - in chronological order of publication.  Since children's literature is particularly adept at reflecting and promoting the dominant ideas of the society in which it is produced, the chronological consideration of these texts reveals contemporary attitudes to such issues as race relations, gender roles, class, war and conflict, and concepts of national identity, as well as the way historical fiction has responded to societal changes since the 1860s.  

The predominant themes of historical fiction set prior to 1900 are: the arrival of settlers in New Zealand; encounters with the country's indigenous inhabitants; the taming of the often hostile landscape; the assertion of the settlers' claims to 'belong' in their new land; and the establishment of New Zealand as a nation with distinctive characteristics.  There are perceptible nuances and differences in the way these themes are discussed depending on the historical moment in which individual authors are writing.  Novels of the Victorian period and early twentieth century reflect the imperialistic and evangelistic ethos of the time, and present the British settlers' right to colonize the land and the ensuing dispossession of Māori as largely unproblematic.  Subsequent historical novels, particularly those written since the 1960s, offer a more inclusive version of New Zealand history, although the lack of historical fiction for children by Māori writers means that Eurocentric views of history continue to dominate, and that all representations of Māori and their history are mediated through Pakeha writers.

Shifts in social attitudes have resulted in changes in the treatment of Māori in historical novels for children, and similar changes have occurred in the portrayal of gender, class, and ethnicity.  The passage of time has seen increased agency and a wider variety of roles allocated to Māori, female and working class characters, as well as greater ethnic diversity.  Developments in New Zealand historiography are also reflected in fiction, although at times historical fiction prefigures written histories, or provides alternative views by depicting the experience of women, children and Māori, who often did not feature in conventional histories.  While many historical novels for children, especially the earlier texts, are adventure stories set in the past and are not necessarily concerned with historical verisimilitude, an increasing number attempt to present authentic recreations of historical periods, including accounts of actual people and events, based on extensive research, and reinforced with peritextual material in the form of historical notes, bibliographies, maps and photographs.  

The role of New Zealand historical fiction for children and young people has been not only to entertain young readers and inform them about their country's past, but to create and foster a sense of national identity.

text: 'Making its own history': New Zealand historical fiction for children,1862-2008 This thesis considers historical fiction for children and young people dealing with New Zealand history from the arrival of the first Polynesian settlers to the end of the nineteenth century.  It provides both a comprehensive survey of historical novels published between 1862 and the end of 2008, and an analysis of the way the same historical events and periods have been depicted in historical novels written at different times.  Individual chapters discuss books set during specific historical periods or dealing with particular events - the pre-European period, early contact, nineteenth century immigration, the New Zealand Wars, the gold rushes, and the colonial period - in chronological order of publication.  Since children's literature is particularly adept at reflecting and promoting the dominant ideas of the society in which it is produced, the chronological consideration of these texts reveals contemporary attitudes to such issues as race relations, gender roles, class, war and conflict, and concepts of national identity, as well as the way historical fiction has responded to societal changes since the 1860s.  

The predominant themes of historical fiction set prior to 1900 are: the arrival of settlers in New Zealand; encounters with the country's indigenous inhabitants; the taming of the often hostile landscape; the assertion of the settlers' claims to 'belong' in their new land; and the establishment of New Zealand as a nation with distinctive characteristics.  There are perceptible nuances and differences in the way these themes are discussed depending on the historical moment in which individual authors are writing.  Novels of the Victorian period and early twentieth century reflect the imperialistic and evangelistic ethos of the time, and present the British settlers' right to colonize the land and the ensuing dispossession of Māori as largely unproblematic.  Subsequent historical novels, particularly those written since the 1960s, offer a more inclusive version of New Zealand history, although the lack of historical fiction for children by Māori writers means that Eurocentric views of history continue to dominate, and that all representations of Māori and their history are mediated through Pakeha writers.

Shifts in social attitudes have resulted in changes in the treatment of Māori in historical novels for children, and similar changes have occurred in the portrayal of gender, class, and ethnicity.  The passage of time has seen increased agency and a wider variety of roles allocated to Māori, female and working class characters, as well as greater ethnic diversity.  Developments in New Zealand historiography are also reflected in fiction, although at times historical fiction prefigures written histories, or provides alternative views by depicting the experience of women, children and Māori, who often did not feature in conventional histories.  While many historical novels for children, especially the earlier texts, are adventure stories set in the past and are not necessarily concerned with historical verisimilitude, an increasing number attempt to present authentic recreations of historical periods, including accounts of actual people and events, based on extensive research, and reinforced with peritextual material in the form of historical notes, bibliographies, maps and photographs.  

The role of New Zealand historical fiction for children and young people has been not only to entertain young readers and inform them about their country's past, but to create and foster a sense of national identity.

year: 2010