title: Life history of fluvial and lacustrine land-locked koaro (Galaxias brevipinnis) Günther (Pisces: galaxiidae) in the Tarawera lakes

authors: Young, Kim D.

abstract: Biological diversity in New Zealand has been seriously degraded as a result of human induced disturbances which include the introduction of many exotic species. Freshwater ecosystems have not escaped damage, with the introduction of primarily sports fish suspected to be a significant contributing factor in diminished native biological freshwater values. This is reflected by range and population reductions of several native fish species. 

One of these species is koaro (Galaxias brevipinnis), for which abundance in land-locked populations in the central North Island lakes has significantly declined. Koaro were once abundant in these lakes, and pre-European harvest in both its juvenile (whitebait) and adult (kokopu) form, comprised an important food resource for inland Maori. Since the introduction of recreational trout species to these lakes in the late 1880s, followed by the introduction of common smelt (Retropinna retropinna) in the early 1900s, the abundance of koaro has dramatically declined to the extent that, in these lakes, the species is now considered rare. 

To date, the interactions between recreational trout species, common smelt, and koaro populations have not been established, and the life-history of land-locked koaro is not fully understood. In particular, the extent of movement between lake and stream habitats remains unclear. However, a collaborative project between the indigenous people of the Rotorua Lakes (Te Arawa) and the Department of Conservation to restore a koaro population in one Rotorua lake, has driven a need to gain a better understanding of the biology and ecology of land-locked koaro. This includes identifying threats to important life-history stages and understanding the role of tributary streams.

During July 1999 to February 2001, lacustrine and fluvial koaro were studied in Lake Tarawera and Lake Okareka and their tributary streams. Both lakes are part of the Tarawera lakes group, a subgroup of the Rotorua lakes situated in the central North Island. Fyke netting was used to sample lacustrine koaro on a monthly basis from January 2000 to February 2001, and seasonal two-pass reduction electric fishing at five sites in the tributary streams took place in April, July and November 2000 and February 2001. All fish larger than 70 mm total length were tagged with a passive implant transponder. Spawning season and location, together with size and growth of lake and stream fish were determined. Movement of lake fish within the littoral zone was also investigated. 

The study found that lake and stream koaro may belong to two sub-populations indicated by differences in size, growth rate, spawning time and locality, and return of lake and stream koaro to natal habitats. The life-history of stream koaro has remained similar to that of its diadromous counterparts. Stream fish were found to spawn and hatch in stream environs, rear as larvae in the lake environs, and return to tributary streams as juvenile fish. Lake fish by contrast, most likely spawn in the lake itself, and results suggest that no juvenile migration of lake spawned fish to tributary streams occurs. Consequently, it was concluded that tributary streams may play little role in the life-history of lacustrine koaro.

Abundance of lacustrine koaro in both Lake Tarawera and Lake Okareka was low in comparison to lakes where trout species or common smelt are absent, and abundance of post-whitebait koaro (greater than 45 mm total length coloured and patterned) in both tributary streams studied was also low where rainbow trout (Oncorhynchus mykiss) were proportionally present in greater abundance. Important life-history stages were found to be subject to competition and predation by a combination of rainbow trout and common smelt in both lakes and streams.

Given the above, restoration programmes for land-locked koaro will need to be undertaken at the population level to enhance the survival of larval and juvenile life-history stages. This will need to occur at an ecosystem scale, and include the management of the combined effects of trout and common smelt in both lake and respective tributary stream environs.

text: Life history of fluvial and lacustrine land-locked koaro (Galaxias brevipinnis) Günther (Pisces: galaxiidae) in the Tarawera lakes Biological diversity in New Zealand has been seriously degraded as a result of human induced disturbances which include the introduction of many exotic species. Freshwater ecosystems have not escaped damage, with the introduction of primarily sports fish suspected to be a significant contributing factor in diminished native biological freshwater values. This is reflected by range and population reductions of several native fish species. 

One of these species is koaro (Galaxias brevipinnis), for which abundance in land-locked populations in the central North Island lakes has significantly declined. Koaro were once abundant in these lakes, and pre-European harvest in both its juvenile (whitebait) and adult (kokopu) form, comprised an important food resource for inland Maori. Since the introduction of recreational trout species to these lakes in the late 1880s, followed by the introduction of common smelt (Retropinna retropinna) in the early 1900s, the abundance of koaro has dramatically declined to the extent that, in these lakes, the species is now considered rare. 

To date, the interactions between recreational trout species, common smelt, and koaro populations have not been established, and the life-history of land-locked koaro is not fully understood. In particular, the extent of movement between lake and stream habitats remains unclear. However, a collaborative project between the indigenous people of the Rotorua Lakes (Te Arawa) and the Department of Conservation to restore a koaro population in one Rotorua lake, has driven a need to gain a better understanding of the biology and ecology of land-locked koaro. This includes identifying threats to important life-history stages and understanding the role of tributary streams.

During July 1999 to February 2001, lacustrine and fluvial koaro were studied in Lake Tarawera and Lake Okareka and their tributary streams. Both lakes are part of the Tarawera lakes group, a subgroup of the Rotorua lakes situated in the central North Island. Fyke netting was used to sample lacustrine koaro on a monthly basis from January 2000 to February 2001, and seasonal two-pass reduction electric fishing at five sites in the tributary streams took place in April, July and November 2000 and February 2001. All fish larger than 70 mm total length were tagged with a passive implant transponder. Spawning season and location, together with size and growth of lake and stream fish were determined. Movement of lake fish within the littoral zone was also investigated. 

The study found that lake and stream koaro may belong to two sub-populations indicated by differences in size, growth rate, spawning time and locality, and return of lake and stream koaro to natal habitats. The life-history of stream koaro has remained similar to that of its diadromous counterparts. Stream fish were found to spawn and hatch in stream environs, rear as larvae in the lake environs, and return to tributary streams as juvenile fish. Lake fish by contrast, most likely spawn in the lake itself, and results suggest that no juvenile migration of lake spawned fish to tributary streams occurs. Consequently, it was concluded that tributary streams may play little role in the life-history of lacustrine koaro.

Abundance of lacustrine koaro in both Lake Tarawera and Lake Okareka was low in comparison to lakes where trout species or common smelt are absent, and abundance of post-whitebait koaro (greater than 45 mm total length coloured and patterned) in both tributary streams studied was also low where rainbow trout (Oncorhynchus mykiss) were proportionally present in greater abundance. Important life-history stages were found to be subject to competition and predation by a combination of rainbow trout and common smelt in both lakes and streams.

Given the above, restoration programmes for land-locked koaro will need to be undertaken at the population level to enhance the survival of larval and juvenile life-history stages. This will need to occur at an ecosystem scale, and include the management of the combined effects of trout and common smelt in both lake and respective tributary stream environs.

year: 2002

title: Eke panuku, eke tangaroa! How Black Ferns 7s athletes navigate Instagram and inspire the next generation in Aotearoa

authors: Keet, Thandiwe Maia

subjects: Gender

abstract: This thesis considers the role of Instagram in the lives of players on the New Zealand Black Ferns 7s rugby team, and audience engagement with players’ social media accounts. Using a mana wāhine methodology, this study explores how Black Ferns 7s players utilize and navigate Instagram, through mixed-methods enquiry, including a social media analysis of 8 players’ accounts, interviews with 3 Black Ferns 7s players, and talanoa sessions with members of the women’s rugby community in the Bay of Plenty, supplemented by input from Black Ferns players and fans via direct messages on Instagram. The quantitative social media analysis identified 4 key themes in players’ Instagram posts: achievement, team & rugby, life outside rugby, and culture & vulnerability. The analysis reveals that players post the most regarding their “team & rugby”, generating an “athlete first” self- representation. It finds a statistically significant difference in the thematic content of Instagram posts based on squad seniority and the number of followers a player has. Followers were found to engage most with posts regarding “achievement”, and the least with posts regarding “culture and vulnerability”.
The interviews elaborate upon these quantitative differences by highlighting why athletes specifically use Instagram, insights into Black Ferns aspirational team dynamics, and the importance of a player’s life outside of rugby. The thematic analysis also reveals the digital economic and collective labour involved in producing social media content as a member of this team, and what it means to be culturally “authentic” online in Aotearoa. It reveals the unique elements generated by the team-sport context of this study, including intra-team differences in social media usage. Furthermore, hauora, Indigenous role modeling, and Tall Poppy Syndrome emerge as factors particularly unique to the cultural context within which this study takes place. The discussions culminate in the establishment of a layered understanding of the external, internal, and individual factors which shape Instagram posting habits, and the features which most significantly impact why audiences follow the curated displays Black Ferns 7s athletes provide online.
This project contributes to international literature on sportswomen’s use of social media, demonstrating the powerful ways that players support one another in what, when, and how they post, and the importance of cultural identity in Māori and Pasifika players’ social media engagement. It further reveals the importance of team culture in shaping individual players’ social media and audience engagement. This thesis also highlights the significance of sporting and cultural histories and intersectional identities in digital self-representation and fan engagement with sportswomen’s social media usage.

text: Eke panuku, eke tangaroa! How Black Ferns 7s athletes navigate Instagram and inspire the next generation in Aotearoa This thesis considers the role of Instagram in the lives of players on the New Zealand Black Ferns 7s rugby team, and audience engagement with players’ social media accounts. Using a mana wāhine methodology, this study explores how Black Ferns 7s players utilize and navigate Instagram, through mixed-methods enquiry, including a social media analysis of 8 players’ accounts, interviews with 3 Black Ferns 7s players, and talanoa sessions with members of the women’s rugby community in the Bay of Plenty, supplemented by input from Black Ferns players and fans via direct messages on Instagram. The quantitative social media analysis identified 4 key themes in players’ Instagram posts: achievement, team & rugby, life outside rugby, and culture & vulnerability. The analysis reveals that players post the most regarding their “team & rugby”, generating an “athlete first” self- representation. It finds a statistically significant difference in the thematic content of Instagram posts based on squad seniority and the number of followers a player has. Followers were found to engage most with posts regarding “achievement”, and the least with posts regarding “culture and vulnerability”.
The interviews elaborate upon these quantitative differences by highlighting why athletes specifically use Instagram, insights into Black Ferns aspirational team dynamics, and the importance of a player’s life outside of rugby. The thematic analysis also reveals the digital economic and collective labour involved in producing social media content as a member of this team, and what it means to be culturally “authentic” online in Aotearoa. It reveals the unique elements generated by the team-sport context of this study, including intra-team differences in social media usage. Furthermore, hauora, Indigenous role modeling, and Tall Poppy Syndrome emerge as factors particularly unique to the cultural context within which this study takes place. The discussions culminate in the establishment of a layered understanding of the external, internal, and individual factors which shape Instagram posting habits, and the features which most significantly impact why audiences follow the curated displays Black Ferns 7s athletes provide online.
This project contributes to international literature on sportswomen’s use of social media, demonstrating the powerful ways that players support one another in what, when, and how they post, and the importance of cultural identity in Māori and Pasifika players’ social media engagement. It further reveals the importance of team culture in shaping individual players’ social media and audience engagement. This thesis also highlights the significance of sporting and cultural histories and intersectional identities in digital self-representation and fan engagement with sportswomen’s social media usage.

year: 2022

title: Feed-forward mechanisms: Addiction-like behavioral and molecular adaptations in overeating

authors: Alsiö, Johan

subjects: obesity

abstract: Food reward, not hunger, is the main driving force behind eating in the modern obesogenic environment. Palatable foods, generally calorie-dense and rich in sugar/fat, are thus readily overconsumed despite the resulting health consequences. Important advances have been made to explain mechanisms underlying excessive consumption as an immediate response to presentation of rewarding tastants. However, our understanding of long-term neural adaptations to food reward that oftentimes persist during even a prolonged absence of palatable food and contribute to the reinstatement of compulsive overeating of high-fat high-sugar diets, is much more limited. Here we discuss the evidence from animal and human studies for neural and molecular adaptations in both homeostatic and non-homeostatic appetite regulation that may underlie the formation of a “feed-forward” system, sensitive to palatable food and propelling the individual from a basic preference for palatable diets to food craving and compulsive, addiction-like eating behavior.

text: Feed-forward mechanisms: Addiction-like behavioral and molecular adaptations in overeating Food reward, not hunger, is the main driving force behind eating in the modern obesogenic environment. Palatable foods, generally calorie-dense and rich in sugar/fat, are thus readily overconsumed despite the resulting health consequences. Important advances have been made to explain mechanisms underlying excessive consumption as an immediate response to presentation of rewarding tastants. However, our understanding of long-term neural adaptations to food reward that oftentimes persist during even a prolonged absence of palatable food and contribute to the reinstatement of compulsive overeating of high-fat high-sugar diets, is much more limited. Here we discuss the evidence from animal and human studies for neural and molecular adaptations in both homeostatic and non-homeostatic appetite regulation that may underlie the formation of a “feed-forward” system, sensitive to palatable food and propelling the individual from a basic preference for palatable diets to food craving and compulsive, addiction-like eating behavior.

year: 2012