Scientist says tropical fish documented by divers signals warming Atlantic waters

Aug 2, 2019 | 8:16 AM

HALIFAX — A marine biologist is taking notice of stunning images of tropical fish photographed by an amateur diver in the warming waters off Nova Scotia’s southern shore.

Boris Worm of Dalhousie University — who has also been a diver for decades — says the seahorses, spotfin butterfly fish and bluespotted cornetfish would once have been considered a rarity in Nova Scotia.

However, diver Lloyd Bond says he’s been able to capture more digital images of the colourful species over the past six years at Paddy’s Head in St. Margarets Bay and provide them to scientists like Worm.

The marine biologist says he sees the presence of the fish as another sign of human-influenced climate change arriving, with some effects that could become worrying to the existing fisheries.

Last year’s scientific summary of warming in the Department of Fisheries and Oceans report “Canada’s Oceans Now,” stated two of the five warmest years in recorded history occurred in 2012 and 2014 in air temperatures and noted sea surface temperatures followed that trend.

In addition, the Gulf Stream’s influence is increasing, resulting in “high deep-water temperatures on the Scotian Shelf and in the deep channels of the Gulf of St. Lawrence.”

Worm says it’s his view that some eddies of the Gulf Stream may be spinning into bays and inshore waters, bringing the tropical and sub-tropical fish into coastal inlets where divers see them.

He says while the presence of the fish themselves isn’t likely to disrupt ecosystems, there’s the possibility that invasive predatory species and warm water diseases won’t be far behind.

 

Michael Tutton, The Canadian Press