Canadian Stripers Slam Salmon
April 13, 2018
In a rare report of species population increase, Striped Bass have rebounded with a 300% expansion in numbers off the waters of eastern Canada. Every silver lining has a potential dark cloud, however, and the implications for environmental analysts are concerning.
As covered by the CBC news in New Brunswick, the population of Striped Bass in the lower Gulf of St. Lawrence have inexplicably exploded in the last year, as measured by the federal Department of Fisheries and Oceans. Department scientists are quoted as saying the numbers of Stripers tripled between 2016 and 2017 to an estimated one million fish -- in total, a 100-fold increase from twenty years ago.
Striped Bass are an anadromous species that are capable of living in both fresh and salt water, spawning in fresh water but maturing in the ocean, much as salmon. While Stripers are considered a cold water fish, their typical range does not have a significant amount of overlap with salmon, however. But nature abhors a vacuum, and the numbers of Stripers now off of New Brunswick indicate that something has changed in the environment that is allowing the voracious piscenovores to thrive
DFO scientist Scott Douglas provided the following statement.
"Something changed in 2017 that motivated striped bass to swim [farther] north during the summer months than previously known. There has been some suggestion that it may be linked to climate change and warming waters which 'opened' habitat which was previously too cold for the fish to occupy,"
While Striped Bass are an excellent sport fish, what is of concern is the increase in Canadian Striper numbers seems to have coincided with a sharp decrease in the population of Cod in the area, to the point that is being described by officials as a collapse. This is of significant importance to the regional economy. Although Stripers are of commercial value, the market demand for Cod is considerably stronger -- especially in the United Kingdom, a reasonably close shipping partner for eastern Canadian fisheries. Cod are a globally extant species, however, and are harvested in the northern pacific as well. Consumers in the UK aren't likely to change their taste in fish and chips overnight, and will probably source Cod even at a premium price.
Another notable aspect of the perceived environmental change is a large increase in the numbers of Lobster in the area -- an obvious economic plus, but not for fishermen whose boats are configured to catch Cod. Cod are a bottom foraging predator that eat Lobster, and a reduction in their numbers has probably allowed the Lobsters to proliferate. Warming waters may have affected the ability of the cod to spawn, or the survivability of their larvae, which shelter and mature in brackish water estuaries off the mouths of rivers that empty into the sea -- prime hunting grounds for Striped Bass.
Why should you care, Bro? While Stripers are a cool fly rod target, they are probably decimating any Atlantic Salmon smolts that are coming down river into the Gulf, a potentially serious threat to an endangered and fundamentally important species to the sport of fly fishing. Stripers grow big, fast, and there is a reason for that. They are extremely aggressive predators that eat anything that can fit in their mouths while stalking shallow bays and the middle of the water column offshore. Huge numbers of Striped Bass staging off the coast of New Brunswick could potentially spell an end to Atlantic Salmon in the area, something that decades of federal and advocate efforts have worked to protect against.
The Washington Post recently reported that NOAA had measured ocean temperature warming off New England, and determined that it is increasing in temperature faster than in any ocean environment on earth -- half a degree Fahrenheit per year. This stunning finding has pushed researchers to find out the exact cause of the change, and evidence is mounting to support a conclusion of a massive upcoming shift in climate for the north Atlantic on both sides of the ocean.
The Atlantic Meridional Overturning Circulation, or AMOC, Is something you should have on your radar. Otherwise known as the Gulf Stream, it is a recirculation of staggering amounts of sea water between Northern and tropical latitudes that have provided western Europe with a relatively mild climate for the last 150 years. The AMOC ferries salty warm water from the Gulf of Mexico northward, veering east off of Greenland where it then collides with England. Meanwhile, cold water of relatively less salinity is pouring off of the Greenland Ice Sheet, where it then travels along the ocean bottom southward for thousands of miles to the tropics to become part of the gigantic cycle. The problem is that the AMOC has now been measured to be slowing down, and probably from anthropogenic -- human caused -- climate change. Warm flows from the Gulf are now migrating west into historically cold water off Canada due to a blockage being caused by massive amounts of meltwater coming off Greenland.
This has major implications for climatologists, not only with potential impacts for weather in the north Atlantic, but also because a weakened AMOC provides less ability for the ocean to convert atmospheric CO2, creating a feedback loop for the whole process. Greenhouse gas increase is acknowledged to be a driver of sea level rise, with severe consequences for coastal cities worldwide.
Climate change is causing unforeseen effects in both ecology and the physical aspects of the planet. Scientific observation and analysis of the enormous dynamics in play are providing insights for how to mitigate the destructive aspects of this, and how best to adapt to what cant be changed.