title: Protogynous sex change in sexually immature spotty wrasse (Notolabrus celidotus)

authors: Hamer, Tessa Ellen

subjects: Aquaculture

abstract: One of the most unique forms of sexual plasticity can be witnessed in sequentially hermaphroditic fish, which begin as one sex and change to another at some stage in their lifecycle. The endemic protogynous spotty wrasse (Notolabrus Celidotus), has historically been considered monandric although two male morphs appear to exist. To date the majority of research has focused on sexually mature females that are changing sex to become terminal phase males. The current study seeks to describe sex change in sexually immature females that are transitioning to become initial phase males. This was achieved through analysis of gonadal histology as well as expression of three key sex differentiation related genes (amh, dmrt1 and cyp19a1a). Fish (n=141) were caught from the Tauranga Harbour ranging in size from 52-270 mm TL from May-June 2022. The smallest transitional fish identified was 52 mm TL and the smallest IP male detected in this study were 72 mm TL, indicating IP male spotty wrasse likely reach sexual maturity at a much earlier and smaller developmental stage than previously realised. Expression of amh and dmrt1 showed a clear male-bias across sex change, with the former being upregulated in early sex change. The aromatase gene, cyp19a1a showed an overall female-biased expression pattern despite having some unexpected upregulation in the mid stages of sex change. The results supported previous reports that all juvenile spotty wrasse are female first before some individuals undergo pre-maturational sex change to become IP males. Having clarified the process of sex change leading to IP male formation and considering data from other studies of IP and TP testicular structure in this species, it seems no longer tenable to consider them monandric.

text: Protogynous sex change in sexually immature spotty wrasse (Notolabrus celidotus) One of the most unique forms of sexual plasticity can be witnessed in sequentially hermaphroditic fish, which begin as one sex and change to another at some stage in their lifecycle. The endemic protogynous spotty wrasse (Notolabrus Celidotus), has historically been considered monandric although two male morphs appear to exist. To date the majority of research has focused on sexually mature females that are changing sex to become terminal phase males. The current study seeks to describe sex change in sexually immature females that are transitioning to become initial phase males. This was achieved through analysis of gonadal histology as well as expression of three key sex differentiation related genes (amh, dmrt1 and cyp19a1a). Fish (n=141) were caught from the Tauranga Harbour ranging in size from 52-270 mm TL from May-June 2022. The smallest transitional fish identified was 52 mm TL and the smallest IP male detected in this study were 72 mm TL, indicating IP male spotty wrasse likely reach sexual maturity at a much earlier and smaller developmental stage than previously realised. Expression of amh and dmrt1 showed a clear male-bias across sex change, with the former being upregulated in early sex change. The aromatase gene, cyp19a1a showed an overall female-biased expression pattern despite having some unexpected upregulation in the mid stages of sex change. The results supported previous reports that all juvenile spotty wrasse are female first before some individuals undergo pre-maturational sex change to become IP males. Having clarified the process of sex change leading to IP male formation and considering data from other studies of IP and TP testicular structure in this species, it seems no longer tenable to consider them monandric.

year: 2023

title: Automatic Weighing for Dry Stock

authors: Smialowski, Grzegorz

subjects: weighing

abstract: The aim of the research was to develop an accurate weight estimation algorithm for dry stock cattle using unsupervised walk-over equipment and to investigate the accuracy of the dairy cow algorithm for dry stock animals. Several customers and research organisations requested a suitable product for weighing dry stock, similar to the automatic weighing system for dairy cows. The development of the algorithm had to take into account the erratic behaviour of dry stock cattle. An additional requirement for the research was to improve cost effectiveness of the existing system, by removing the need for the lead-on platform.
Data was collected from a series of dry stock herds, as they walked over the existing dairy cow walk-over weighing (WOW) platform, in either a paddock or a stockyard. All dry stock cattle were static weighed before walking over the WOW to obtain an accurate true weight of the animal. The weight estimations produced by the dairy cow algorithm were recorded and the raw load cell data was captured. The raw load cell data was then used to devise a new algorithm specifically for dry stock cattle. The new algorithm was tested against the collected load cell data from various herds. The dairy cow algorithm results were used to compare the accuracy of the existing algorithm on dry stock cattle.
The new devised algorithm used a threshold to locate a rough start and end point for each walk-over event. The data between the initial start and end points was processed to locate the period which had the full weight of the cattle located on the weighing platform. The algorithm estimated the weight of the animal from the data between these points.
It was found that the dairy cow algorithm was nearing the required accuracy, but was not able to determine weights for the majority of the animals. The new algorithm devised for dry stock cattle was unable to obtain an improvement in accuracy, but was able to estimate weights for a greater proportion of the cattle. Additionally the new algorithm was successful in eliminating the need for the lead-on platform for detecting animals.

text: Automatic Weighing for Dry Stock The aim of the research was to develop an accurate weight estimation algorithm for dry stock cattle using unsupervised walk-over equipment and to investigate the accuracy of the dairy cow algorithm for dry stock animals. Several customers and research organisations requested a suitable product for weighing dry stock, similar to the automatic weighing system for dairy cows. The development of the algorithm had to take into account the erratic behaviour of dry stock cattle. An additional requirement for the research was to improve cost effectiveness of the existing system, by removing the need for the lead-on platform.
Data was collected from a series of dry stock herds, as they walked over the existing dairy cow walk-over weighing (WOW) platform, in either a paddock or a stockyard. All dry stock cattle were static weighed before walking over the WOW to obtain an accurate true weight of the animal. The weight estimations produced by the dairy cow algorithm were recorded and the raw load cell data was captured. The raw load cell data was then used to devise a new algorithm specifically for dry stock cattle. The new algorithm was tested against the collected load cell data from various herds. The dairy cow algorithm results were used to compare the accuracy of the existing algorithm on dry stock cattle.
The new devised algorithm used a threshold to locate a rough start and end point for each walk-over event. The data between the initial start and end points was processed to locate the period which had the full weight of the cattle located on the weighing platform. The algorithm estimated the weight of the animal from the data between these points.
It was found that the dairy cow algorithm was nearing the required accuracy, but was not able to determine weights for the majority of the animals. The new algorithm devised for dry stock cattle was unable to obtain an improvement in accuracy, but was able to estimate weights for a greater proportion of the cattle. Additionally the new algorithm was successful in eliminating the need for the lead-on platform for detecting animals.

year: 2013

title: Surplus Public Works Land: The Crown's Special Duty to Maori

authors: Grayson, Michael Robert

subjects: Maori

abstract: The Crown's obligations to Maori regarding the offer back of surplus Crown land under s40 of the Public Works Act 1981.

text: Surplus Public Works Land: The Crown's Special Duty to Maori The Crown's obligations to Maori regarding the offer back of surplus Crown land under s40 of the Public Works Act 1981.

year: 2017