This article was published on 23 August 2025 and updated on 20 October 2026.
Update of 20 October 2026
Tracking of juvenile sand tiger sharks in Boston Harbor expanded with four newly tagged animals in 2026. WBUR reports this after joining New England Aquarium researchers on a field trip. Around two dozen sharks have been tagged since 2023, with about a dozen harbor receivers recording their signals.
The data show recurring seasonal use: previously tagged sharks are detected in the harbor again. This helps researchers understand how juveniles use the sheltered coastal habitat. Four new tags are not a population census and cannot establish a percentage growth rate for the population.
The original report appeared on 22 September 2026 and was featured in another radio segment on 19 October. The rebroadcast does not mark the start of a new research program; it adds the documented 2026 season to the earlier account.
Earlier report
Decades of protection measures show results: Increasingly, sand tiger sharks are being sighted in Boston Harbor. Scientists report that the waters are significantly cleaner today than before, and more prey fish are settling, creating ideal conditions for the sharks to use the area as a nursery.
Young sharks in focus of research
Researchers from the New England Aquarium catch juvenile sand tiger sharks to fit them with small transmitters. These send signals to buoys along the US East Coast, allowing the movements of the animals to be tracked. During the procedure, the sharks enter a state of tonic immobility, which makes the process easier. After the transmitters are fitted, the sharks are immediately released.
Sand tiger sharks can grow more than three metres long. In Boston Harbor, research focuses on juveniles using the sheltered harbor as a summer nursery. Many visitors are unaware of their presence.
From decline to slow recovery
Earlier fishing severely depleted populations along the US East Coast. Protections introduced in the late 1990s are intended to allow recovery. Researchers report signs of improvement, but the tagging figures presented here cannot establish an annual population growth rate.
The return of the sharks is also linked to the improvement in water quality in Boston Harbor. Decades of environmental measures have made the habitat more attractive again, so that the sharks now regularly return. Some of the tagged animals migrated hundreds of miles to Florida and later returned to exactly the same stretch of coastline ā an impressive demonstration of this species’ attachment to specific habitats.
Sand tiger sharks deserve more attention
While great white sharks in New England often take centre stage in public attention, experts point out that other species, such as the sand tiger, urgently need more research and protection. Their role in the ecosystem is crucial, yet much remains unknown about their behaviour and population trends. The new transmitters, which can provide data for up to ten years, should help close these knowledge gaps and develop better long-term protection measures.
