Hotter Jersey seas pose challenges for colder water species

Warmer seas off Jersey are driving shifts in marine life, with different species appearing as seawater temperatures rise, a marine expert said. Francis Binney, head of Jersey’s Marine Resources, explained that local land heat strongly influences sea conditions, bringing warmer water earlier than usual. He noted that the typical maximum is 18C (64.4F), while temperatures of around 21C (69.8F) and spikes up to 24C (75.2F) have been recorded. Binney said warmer waters are linked to more sharks and a “resurgence” of tuna, alongside trigger fish and gilthead bream, but also pose “real challenges” for cold-adapted species. He cited losses of species such as chancre crabs becoming common farther north on Swedish and Norwegian coasts, while spider crabs move in. He also described whelks struggling to migrate quickly and reported die-offs over time. The government is working with universities to monitor changes, including filming underwater and relying on locals to report sightings.