Something’s happening out there in the waters of our coast. Chuck Bangley knows it.
was a doctoral student at East Carolina University in 2011 when he
started recording shark activity in North Carolina sounds. In the
previous four decades, nine juvenile bull shark pups were documented in
Pamlico Sound. During the next three years, researchers with the state
Division of Marine Fisheries would catch 54, Bangley said.
is not just the juveniles that were being caught. Neonates – sharks
that are less than one year old — were also appearing in Pamlico Sound.
They begin showing in May and peak a month later, Bangley noted.
“And May and June is the pupping season in both Gulf Coast
nursery habitats and Florida nursery habitats,” he said.
about why so many young bull sharks were showing up, Bangley started
taking water temperature measurements in Pamlico Sound in 2005. The
temperature, he found, had increased about four degrees Celsius. Spring
water temperatures are increasing. Summer temperatures seem to
fluctuate. It’s not clear why.
can’t make any hardcore conclusions from this until we get more data,”
Bangley said. “So it looks like from here we can hypothesize the
juvenile bull shark presence is driven primarily by temperature and
salinity in Pamlico Sound and this matches well with what drives bull
shark presence in other bull shark nurseries as well.”
is not just bull sharks that are responding to changes in the water
temperatures of the Atlantic Ocean, and evidence seems to suggest that
North Carolina is at ground zero for some of the most dynamic changes.
marine transition zones such as the coastal waters along the North
Carolina coast may be areas that will undergo the most ecosystem change
as a result of warming ocean temperatures . . .” note the authors of
study of native fish communities in Onslow Bay, the offshore area
between capes Lookout and Fear.
researchers from the University of North Carolina at Wilmington and the
National Oceanic and Atmospheric Administration examined changes in
marine life below the surface, focusing on depths between 15 and 150
feet. Deeper water temperatures remain more constant, giving
researchers a better picture into changing patterns.
Some of what has been found is reason for concern.
native to the Indo-Pacific seas, have spread from Florida to the
Caribbean and up to North Carolina. Typically 6 or 7 inches in an
aquarium, wild fish can grow to twice that size. With no natural
predators in local waters, the species is endangering the diversity of
reefs off the state’s coast.
lionfish is only one part of what is a complex mosaic that includes
climate change, fish behavior and studies that are at the first steps
to understanding what is happening.
“We are at the infancy of starting to incorporate what we’re learning,” said Erik Williams of the NOAA Lab near Beaufort.
of the work so far has documented changes in distribution of fish
population, and trends are emerging. “Based on annual NOAA fisheries .
. . survey data, the distribution of Atlantic croaker and other species
along the East Coast appear to be shifting poleward,” Robert Griffis,
climate change coordinator for NOAA, wrote in response to an e-mail
change in the distribution to the north is not, however, universal.
“It’s not every species in the Atlantic moving northward,” said Jon
Hare, leader of NOAA’s Oceanography Branch in Narraganset, R.I.
has been studying ocean fish behavior for more than 20 years and the
work he has done is shedding light on shifts in populations of fish
typically seen in North Carolina waters. Some of his best-known work is
associated with summer flounder, croaker and black sea bass. The fish
are moving north but for different reasons.
shift of summer flounder, for instance, showed no link with
temperature, Hare found. That study showed mature summer flounder tend
to naturally shift northward and the temperature of the water did not
seem to affect their behavior.
discussing black sea bass and croaker, Hare draws a distinction. “The
other two are more aligned to ocean temperature,” he said.
especially, seems to be one of the winners if warmer ocean temperatures
continue to expand. In a 2010 paper, Hare wrote, “The
mid-Atlantic region represents the northern limit of Atlantic croaker
and we forecast that climate change will have positive effects on the
talking about his work, Hare cites a number of areas that have yet to
be studied in relation to climate change. Typically pelagic fish are
more mobile than others, but there has not been a detailed examination
of how a shift northward of their prey would affect their patterns.
“That’s one of the questions. As conditions change, how much more
likely are they (pelagic fish) to change their behavior,” he said.
sea temperatures also change the chemical compositions of the oceans,
affecting the salinity and carbonate content. Fish can migrate to areas
more to their liking, but benthic communities, the life at the bottom
of the sea, are not as mobile and the effects on those life forms are
Ocean temperature seems to be the driving force in changes that are seen in North Carolina fish, a point Williams underscores.
“Fish are dynamic,” he said. “They will move around based on water temperature.”
article is provided by Coastal Review Online, an online news service
covering North Carolina's coast. For more news, features, and
information about the coast, go to www.coastalreview.org.)