For the first time, the results of the study of the age and growth of blue hake Antimora rostrata in the waters of the Lazarev and Weddell seas (Antarctic) are presented. The longline catches were represented by fish from 42 to 69 cm in total length with weights between 420 and 2,900 g, and most individuals aged 25 to 27 years. A minimum age of 16 years was observed in a fish 47 cm long and weighing 450 g, while a maximum age of 35 years was recorded for an individual of 69 cm in length and 1,640 g in weight. The blue hake in the Lazarev and Weddell seas shows similar growth patterns to the fish from the Ross Sea and waters off Greenland.

The phenomenon of a massive vertebral deformity was recorded in the radiating Labeobarbus assemblage from the middle reaches of the Genale River (south-eastern Ethiopia, East Africa). Within this sympatric assemblage, five trophic morphs—generalized, lipped, piscivorous and two scraping feeders—were reported between 1993 and 2019. In 2009, a new morph with prevalence of ~10% was discovered. The new morph, termed ‘short’, had an abnormally shortened vertebral column and a significantly deeper body. This type of deformity is common in farmed Atlantic salmon and other artificially reared fish, but is rare in nature. In the Genale Labeobarbus assemblage, the deformity was present exclusively within the generalized and lipped morphs. The short morph had between seven and 36 deformed (compressed and/or fused) vertebrae. Their body depth was positively correlated with number of deformed vertebrae. In another collection in 2019, the short morph was still present at a frequency of 11%. Various environmental and genetic factors could contribute to the development of this deformity in the Genale Labeobarbus, but based on the available data, it is impossible to confidently identify the key factor(s). Whether the result of genetics, the environment, or both, this deep-bodied phenotype is assumed to be an anti-predator adaptation, as there is evidence of its selective advantage in the generalized morph. The Genale monstrosity is the first reported case of a massive deformity of the vertebral column in a natural population of African fishes.

AbstractAge and growth of blue antimora Antimora rostrata were examined for the first time in the waters of Kerguelen and Crozet Islands (southern Indian Ocean, sub-Antarctic). The longline catches were represented by fish ranging from 39 to 72 cm in total length with weights between 400 and 3310 g, aged 16– 41 years. A minimum age of 16 years was observed in a fish 39 cm long, while a maximum age of 41 years was recorded for an individual of 70 cm in length and 3310 g in weight. The age classes with the greatest numbers were represented by fish aged 34 years (9%), 28 years (9%) and 29 years (8%), which together accounted for 26% of the total catch. The blue antimora in the southern Indian Ocean shows similar growth rates to those of individual fish from the Ross, Lazarev and Weddell Seas and southeastern Greenland, which may indicate the population unity of the species within the Antarctic and sub-Antarctic waters or similar habitat conditions in these areas.

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Age and growth of blue antimora Antimora rostrata were examined in the waters off New Zealand and Macquarie Island (southwestern Pacific). Samples off Macquarie Island were collected from bycatch in the Patagonian toothfish longline fishery. Individuals between 20 and 44 years in age measured between 37.6–71.1 cm in total length. Bottom trawl catches from New Zealand waters consisted of smaller and younger fish (11 to 38 years), measuring 22.5–52.5 cm long. The age classes with the greatest numbers in the former area were represented by fish aged 33–34 years (25.7%). In the latter area, the most numerous age classes were 21–23 years (12.1%), 28–29 years (17.6%), and 32 years (6.6%). The blue antimora from off the Macquarie Island show similar growth rates to those of individual fish from the Ross, Lazarev and Weddell Seas, waters off the Kerguelen and Crozet Islands, and southeastern Greenland. Individuals from New Zealand waters demonstrate the slowest growth rates compared to other parts of the species’ range but are quite similar to individuals from the Flemish Cap area. Further research to identify the stock structure of this broadly distributed species is warranted to provide context to differences in growth rates observed between populations.

This study presents the first data of growth and age of Schmidt’s cod Lepidion schmidti, a rare and poorly studied member of the Moridae family (Gadiformes, Teleostei). The research was focused on the Emperor Seamounts area with the aim of investigating the age, growth rates, and longevity of this species. The analysis involved examining annual growth increments on sagittal otoliths. Data were taken from longline catches in 2014 and 2016, resulting in the collection of 140 individuals and the use of 70 otoliths for age determination. The results revealed that Schmidt’s cod can live for up to 49 years, with a mean age of 31.5 years in the catches. The relationship between body weight and total length was described by a power function, indicating positive allometric growth. The most suitable growth model for this species was determined to be the Von Bertalanffy growth equation. These results provide valuable insights to add to the limited knowledge of growth and age in the Moridae family and emphasize the long lifespan and slow growth of Schmidt’s cod.

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