Notes on age determination, size and age structure, longevity and growth of co‐occurring macrourid fishes

Abstract

Nineteen species of the deep‐water fish family Macrouridae inhabit the Mid‐Atlantic Ridge (MAR) of the North Atlantic. Size and age structure, longevity and length at age were explored for seven of the more abundant species: Coryphaenoides armatus, Coryphaenoides brevibarbis, Coryphaenoides carapinus, Coryphaenoides guentheri, Coryphaenoides mediterraneus, Coryphaenoides rupestris and Macrourus berglax. The otoliths from these species had growth increments resembling those accepted as annuli in other deep‐water species for which validation experiments have been conducted. Based on the counts of these growth increments, age estimates were derived as the basis for studies of age structure, growth and longevity. All the species appeared to have relatively low growth rates, but the interspecific variation in longevity illustrates that there is a considerable variation within the family and among species inhabiting the same deep‐sea environment. Most of the species likely complete full life cycles on the MAR, but it is probable that both the youngest and the largest‐oldest individuals of some of the species were not sampled adequately.

Bayesian estimation of the age and growth of the round stingray (Urobatis halleri) in the Gulf of California in Mexico

“…We avoided exploring other models with more parameters because the WAIC penalizes them or because they do not have any biological significance (Richards, 1959;Katsanevakis, 2006). The continuous growth pattern observed in this study (as indicated by parameter estimates from the VBGF) and the representativeness of most age groups indicate that the round stingray completes its life cycle in the study area (Bergstad et al, 2021). Interestingly, the round stingray has been reported to segregate by size and life stage (Silva-Garay and Lowe, 2021), but there are no signs of segregation in our data set.…”

Modal and empirical lengths at sexual maturity for six deep-sea species in Ecuadorian oceanic waters

“…Much of the information is related to C. armatus, mentioned as an abundant species living in deep habitats with maximum lengths over 87 cm total length (TL) and longevity of ca. 40 years (Iwamoto and Stein 1974;Yeh and Drazen 2011;Bergstad et al 2021). Hydrolagus melanophasma was reported in the southeastern Pacific on the last decade as part of catches in the Patagonian toothfish fishery (Bustamante et al 2012;Araya et al 2020;Alfaro-Shigueto et al 2022); however, its biological aspects remain unknown.…”