Accurate inference of sexual maturity is fundamental to interpreting marine mammal life histories and population structure. Using Bayesian logistic regression models with a hierarchical ordinal (HOF‐style) parameterisation and canonical analysis of principal coordinates (CAP), we evaluate skeletal metrics in the pectoral flippers of common dolphin ( Delphinus delphis ) as indicators of attainment of sexual maturity. HOF models...

A healthy skeletal system is fundamental to fish welfare and performance and a key physiological feature of a robust fish. The presence of skeletal deformities in farmed salmonids is a persistent welfare problem in aquaculture, and one which threatens to impede industry growth. Deformities of the fine bones of fish, such as ribs and intermuscular bones (IBs), have received less attention than vertebral body deformities, despit...

Chinook salmon ( Oncorhynchus tshawytscha ) farmed in New Zealand are known to develop abnormal spinal curvature late in seawater production. Its cause is presently unknown, but there is evidence to suggest a neuromuscular pathology. Using magnetic resonance imaging (MRI), we evaluated the relationship between soft tissue pathology and spinal curvature in farmed Chinook salmon. Regions of interest (ROIs) presenting as patholog...

Reproductive parameters were assessed in 64 male common dolphins ( Delphinus delphis ) examined post-mortem from strandings and bycatch in New Zealand between 1999 and 2020. The stages of male sexual maturation were assessed using morphological measurements and histological examination of testicular tissue. Age was determined via growth layer groups (GLGs) in teeth. The average age (ASM) and length (LSM) at attainment of sexua...

Reproductive biology was assessed in 106 female common dolphins ( Delphinus delphis ) examined post-mortem from stranding and bycatch events along the New Zealand coastline between 1997 and 2019. The average age (ASM) and length (LSM) at sexual maturity was estimated at 7.5 years and 183.5 cm, respectively. The total number of corpora in mature individuals increased with age and appeared to persist throughout life. Ovarian asy...

Vertebral fusions are an established economic concern in farmed Atlantic salmon, but have not been studied in detail in farmed Chinook salmon. Two radiographic studies of vertebral fusions were performed in farmed Chinook salmon. Sixteen of 1,301 (1.2%) smolt and 201 of 2,636 (7.6%) harvest fish had fusions. There were no significant differences in the number of fused vertebrae/fusion in smolt compared with harvest fish. Secon...

Spinal abnormalities are common in farmed Chinook Salmon in New Zealand. We report spinal abnormalities in adult Chinook salmon which were predominantly hatchery reared and released as smolts and which we term free‐living. We compare these to rates seen in farmed New Zealand salmon. 101 free‐living adult salmon were radiographically assessed for spinal curvatures (lordosis, kyphosis, scoliosis; LKS) and other vertebral abnorma...