New studies from the University of Iceland and the Marine and Freshwater Research Institute show that blue whiting in the Northeast Atlantic is not a single stock, as long assumed.
Instead, it is composed of many sub-stocks with different ranges and behaviours. Scientists say this could change how the species is managed in the future.
Many Sub-Stocks, Not One
For decades, fisheries management treated blue whiting as one large population. But a new review in Reviews in Fish Biology and Fisheries shows a more complex picture.
The stock is a mix of regional and wide-ranging sub-groups that mix only at certain times of the year. Each group has its own primary habitat and movement pattern.
The authors argue that these findings should be incorporated into future assessments to ensure the sustainable use of resources.
Key Species in Ecosystem and Economy
Blue whiting is one of the most common species in the Northeast Atlantic. It plays a vital role in the marine food chain, feeding predators such as cod, mackerel, seabirds and marine mammals.
At the same time, it supports major fisheries, with annual catches ranging from 1 to 1.8 million tonnes over the past decade. This makes the species important both ecologically and economically.
New Insights from Icelandic Waters
A second study, published in Marine Ecology Progress Series, analyses nearly 30 years of survey data from waters around Iceland. It shows that blue whiting there includes both migrating adults and young fish using nursery areas.
Scientists identified four main groups in autumn and three in spring. These groups vary in terms of depth, location, and size. A key nursery area is south of Iceland and along the ridge between Iceland and the Faroe Islands. Adult migratory fish are more common east of Iceland in autumn.
The results offer insights into how the species responds to climate change, which could inform future management strategies.