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: Insights into the experiences of older workers and change: Through the lens of selection, optimization and compensation

authors: Unson, Christine

subjects: encore

abstract: Purpose: The study examined the barriers faced, the goals selected, and the optimization and compensation strategies of older workers in relation to career change. Method: Thirty open-ended interviews, 12 in the United States and 18 in New Zealand, were conducted, recorded, transcribed verbatim, and analyzed for themes. Results: Barriers to finding and maintaining work included task difficulty, problems with coworkers and management, lack of self-confidence, health/physical limitations, ageism, and stereotyping. Respondents’ most frequently selected goals for a new career were the desire to help others, work satisfaction, and acquisition of learning. Seventy-five percent of respondents in paid employment had earning an income as a goal. Optimization strategies included drawing on past experience, assessing skills, seeking careers/organizations that fitted their values, and a willingness to accept lower pay or unpaid work. Attitudinal strategies included focus and persistence, optimism, and positive attitudes toward change. The compensation strategies reported were on-the-job training; help from coworkers, clients, or customers; friends and family social support; and professional networks. Management practices considered helpful were flexible work schedules, supervisors’ patience, and formal recognition of the value of older workers. Conclusion: This qualitative study, using the SOC framework, showed that evaluating one’s skills and values, being positive about change, and being part of a supportive work environment were key contributors to adaptive competence.

text: Insights into the experiences of older workers and change: Through the lens of selection, optimization and compensation Purpose: The study examined the barriers faced, the goals selected, and the optimization and compensation strategies of older workers in relation to career change. Method: Thirty open-ended interviews, 12 in the United States and 18 in New Zealand, were conducted, recorded, transcribed verbatim, and analyzed for themes. Results: Barriers to finding and maintaining work included task difficulty, problems with coworkers and management, lack of self-confidence, health/physical limitations, ageism, and stereotyping. Respondents’ most frequently selected goals for a new career were the desire to help others, work satisfaction, and acquisition of learning. Seventy-five percent of respondents in paid employment had earning an income as a goal. Optimization strategies included drawing on past experience, assessing skills, seeking careers/organizations that fitted their values, and a willingness to accept lower pay or unpaid work. Attitudinal strategies included focus and persistence, optimism, and positive attitudes toward change. The compensation strategies reported were on-the-job training; help from coworkers, clients, or customers; friends and family social support; and professional networks. Management practices considered helpful were flexible work schedules, supervisors’ patience, and formal recognition of the value of older workers. Conclusion: This qualitative study, using the SOC framework, showed that evaluating one’s skills and values, being positive about change, and being part of a supportive work environment were key contributors to adaptive competence.

year: 2012

title: Contextualising Māori writing: a study of prose fiction written in English by Witi Ihimaera, Patricia Grace, Keri Hulme and Alan Duff

authors: Calvert, Julia Helen

abstract: All prose fiction written in English by Māori is political on one level or another. The authors considered in this thesis, Witi Ihimaera, Patricia Grace, Keri Hulme and Alan Duff, choose to identify as Māori, but for each writer exactly what this entails implies something different. The diverse range of Māori characters represented in their work illustrates the heterogeneity of contemporary Māori identity. Whilst bearing in mind that there is no fixed Māori identity, this thesis proposes that all fiction written in English by Māori is motivated by a belief that Māori are a disadvantaged group within New Zealand society. 

Three of the four writers, Ihimaera, Grace and Hulme, write against a background of colonisation. Their fiction confronts grievances based on perceived injustices committed against Māori in the past by European colonists and is concerned with the restoration of Māori rights pertaining to land, language, identity and political voice. While all three engage with these issues in their fiction, this thesis specifically considers the way in which Ihimaera treats the theme of land, Grace focuses on issues of education and Hulme explores Māori mythology.

Alan Duff stands apart from the other three writers in his belief that colonisation is not to blame for contemporary Māori disadvantage. Rather, Duff considers the situation to be the result of inherent flaws within Māori society. Through his often didactic writing he proposes that improved Māori socioeconomic levels can only be achieved through a radical structural and economic re-evaluation of Māori culture.

This thesis contextualises the work of the four authors and explores the ways in which their fiction engages with historical and contemporary issues of “race relations” and cultural identity in New Zealand. A sociological approach has been applied to the texts. This approach derives from the Māori writers’ own insistent reading of contemporary Māori identity as the product of historical encounter between Māori and Pākehā. The authors work in a dialectical relationship to previous Pākehā representations of Māori in literature, are historically revisionist, and are frequently adversarial. 

Despite the differences in personal and political perspectives held by the authors, their fictions share a common goal in their search for Māori pathways to empowerment. This thesis argues that prose fiction written in English by Māori writers contributes to the political activism of the Māori people and helps to foster an environment in which new perspectives on Māori culture and bicultural relations can be articulated.

text: Contextualising Māori writing: a study of prose fiction written in English by Witi Ihimaera, Patricia Grace, Keri Hulme and Alan Duff All prose fiction written in English by Māori is political on one level or another. The authors considered in this thesis, Witi Ihimaera, Patricia Grace, Keri Hulme and Alan Duff, choose to identify as Māori, but for each writer exactly what this entails implies something different. The diverse range of Māori characters represented in their work illustrates the heterogeneity of contemporary Māori identity. Whilst bearing in mind that there is no fixed Māori identity, this thesis proposes that all fiction written in English by Māori is motivated by a belief that Māori are a disadvantaged group within New Zealand society. 

Three of the four writers, Ihimaera, Grace and Hulme, write against a background of colonisation. Their fiction confronts grievances based on perceived injustices committed against Māori in the past by European colonists and is concerned with the restoration of Māori rights pertaining to land, language, identity and political voice. While all three engage with these issues in their fiction, this thesis specifically considers the way in which Ihimaera treats the theme of land, Grace focuses on issues of education and Hulme explores Māori mythology.

Alan Duff stands apart from the other three writers in his belief that colonisation is not to blame for contemporary Māori disadvantage. Rather, Duff considers the situation to be the result of inherent flaws within Māori society. Through his often didactic writing he proposes that improved Māori socioeconomic levels can only be achieved through a radical structural and economic re-evaluation of Māori culture.

This thesis contextualises the work of the four authors and explores the ways in which their fiction engages with historical and contemporary issues of “race relations” and cultural identity in New Zealand. A sociological approach has been applied to the texts. This approach derives from the Māori writers’ own insistent reading of contemporary Māori identity as the product of historical encounter between Māori and Pākehā. The authors work in a dialectical relationship to previous Pākehā representations of Māori in literature, are historically revisionist, and are frequently adversarial. 

Despite the differences in personal and political perspectives held by the authors, their fictions share a common goal in their search for Māori pathways to empowerment. This thesis argues that prose fiction written in English by Māori writers contributes to the political activism of the Māori people and helps to foster an environment in which new perspectives on Māori culture and bicultural relations can be articulated.

year: 2002