The whiting, Merlangius merlangus, is a key cold-temperate demersal species in the Black Sea, yet information on its essential habitats and demographic structure remains limited for effective regional management. This study combined fishery-independent bottom trawl surveys with in situ hydrographic observations to identify autumn hotspots of recruits and adults along the southern Black Sea and to assess their relationships with environmental gradients. A stratified random survey (10–125 m) was conducted in autumn 2024, with data collected from 66 hauls. The population showed a strong female bias, with females comprising 67.9% of individuals (F:M = 2.12:1), significantly deviating from a 1:1 sex ratio. Length–weight relationships indicated positive allometric growth in females (b = 3.16), isometric growth in males (b = 3.03), and overall positive allometry for the combined population (b = 3.15). The relative condition factor (Kn) was close to unity (1.01 ± 0.10), suggesting stable body condition during the survey period. Generalized Additive Models with a Tweedie distribution revealed that depth–temperature interactions were the primary drivers of distribution for both recruits and adults, explaining 74.7% and 69.5% of deviance, respectively. Recruits concentrated at 40–75 m within 10–15 °C, while adults extended beyond 100 m, associated with the upper Cold Intermediate Layer. These findings highlight hydrographically dynamic nursery and feeding habitats, underscoring the need for adaptive, habitat-based spatial management of this shared Black Sea stock.
Murat Dağtekin (Wed,) studied this question.