A first attempt to evaluate the age and growth of blue hake Antimora rostrata (Moridae, Gadiformes, Teleostei) from the Lazarev and Weddell seas (Antarctic)

Abstract

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.

Age and growth of Antimora rostrata (Moridae, Gadiformes, Teleostei) from the Kerguelen and Crozet Islands in the southern Indian Ocean

“…According to Novikov and Timokhin (2009), on the underwater ridges of the Indian Ocean at depths ranged 900-1700 m, the sex ratio was close to 1:1 on the Southwest Indian Ridge with some predominance of females (1:1.2-1.4) in other areas. In the Southern Ocean, the number of males in the Lazarev and Weddell seas was higher than females at depths of 1100-1800 m (Vedishcheva et al, 2019). Furthermore, at depths of 800-2000 m in the Ross Sea, the percentage of females was up to 90% (Horn & Sutton, 2015), which is similar to our data (78% vs. 22%).…”

“…The majority of authors who studied the age of blue antimora using otoliths (Fossen & Bergstad, 2006;Horn & Sutton, 2015;Orlov et al, 2018b;Vedishcheva et al, 2019) note the challenges associated with the difficulty in interpreting the otolith zones, which was quite evident in our studies. In this study, we consider all visible rings as annuli similar to other previous studies where age estimations were unvalidated.…”

“…Since the beginning of the 1980s, when determining the age of fish, a "break and burn" method of age determination on otoliths has been widely used, which has proved to be good for demersal (including deep-water) fish of the west coast of the USA and Canada (Beamish & McFarlane, 1987). Taking into account that blue antimora, like many deep-sea fish, is probably a long-lived species (Fossen & Bergstad, 2006;Horn & Sutton, 2015;Magnússon, 2001;Orlov et al, 2018b;Vedishcheva et al, 2019), age was determined in accordance with the methods developed specifically for some long-lived deep-sea fish (Beamish & Chilton, 1982).…”

“…Published information about the life cycle of A. rostrata is limited and fragmentary (Collins, Priede, & Bagley, 1999;Gordon & Duncan, 1985;Iwamoto, 1975;Kulka et al, 2003;Novikov & Timokhin, 2009;Wenner & Musick, 1977). The age and growth of blue antimora have been studied in the waters of Iceland (Magnússon, 2001), the Ross Sea and New Zealand waters (Horn & Sutton, 2015) and the Lazarev and Weddell seas (Vedishcheva, Korostelev, Gordeev, & Orlov, 2019), as well as in several areas of the North Atlantic, including the waters of both coasts of Greenland and the Mid-Atlantic Ridge (Fossen & Bergstad, 2006;Orlov, Vedishcheva, Trofimova, & Orlova, 2018b). However, no age validations were provided in publications documenting those studies.…”

“…In the Ross Sea, catches of blue antimora ranged in age between 11 and 41 years; and in the waters off New Zealand, they ranged between 4 and 28 years (Horn & Sutton, 2015). In catches from southwestern Greenland, individuals aged 7-38 years with a numerical dominance of fish aged from 11 to 21 years were observed (Orlov et al, 2018b), while 25-27-yearold individuals of blue antimora were most numerous in catches in the Lazarev and Weddell seas (Vedishcheva et al, 2019). In our catches, 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.…”