by Joe Wilhelm Jr.
Staff Writer
An update on the investigation of 17 dolphin deaths within the past year raised questions regarding the development of Jacksonville’s port at a Jacksonville Waterways Commission meeting Wednesday.
Rose Borkowski, a Jacksonville University assistant professor of biology and marine science, was asked to give the commission a presentation on dolphin fatalities in Duval County.
The “stranding” of 17 dolphins from May through August along the St. Johns River caused the National Oceanic and Atmospheric Association to declare a marine mammal “unusual mortality event” in October, which opened up funding for an investigation of the cause of the deaths.
“We have been sampling carcasses for infectious agents or toxins,” said Borkowski. “But many of the dolphins were so decomposed that we couldn’t extract enough soft tissue.”
According to the NOAA, a stranding is “an event in the wild where a marine mammal or sea turtle is found dead on the beach or shore or floating in U.S. waters; when a marine mammal or sea turtle is alive on the beach or shore, but unable to return to the water due to sickness or injury or some other obstacle; or when a marine mammal or sea turtle is in the water, but is unable to return to its natural habitat without assistance.”
Multiple strandings lead to the NOAA declaring an “Unusual Mortality Event” under the Marine Mammal Protection Act, and it is described as “a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response.”
Researchers are looking at factors that could have contributed to the deaths, including the algae blooms and foam that appeared in the waters of the St. Johns from Fleming Island through Downtown. Borkowski also addressed the issue of how dredging affects the dolphins.
“Dolphins are sensitive to sounds in the water and the port dredging project was going on at the same time that the event was happening,” said Borkowski. “Did dredging contribute to the event? We don’t know at this point. We are looking for answers.”
Borkowski admitted that it will be difficult to identify dredging as one of the factors that contributed to the event.
“It might be a hard question to get at because you have to look at the sound signatures of dredging to determine it they had an effect,” she said.
State Rep. Lake Ray, a commission member, asked if the research had revealed a change in the salinity of the St. Johns River, and whether that could have affected the dolphins.
“The salinity of the river changes all the time,” said Quinton White, executive director of the JU Marine Science Research Institute. “We have not seen a decrease in the salinity of the river in the sense of a trend. We are normally between 12-18 parts per thousand, but we have seen readings up to 23 parts per thousand recently.”
The commission plans to monitor the developments of the investigation.
The commission also invited Vince Seibold, division chief of the City’s Environmental Quality Division of the Environmental and Compliance Department, to talk about opening the shellfish beds in Duval County.
“We have received some interest from St. Johns County to open the shellfish beds in Duval County,” said John Crescimbeni, commission chair. “What is the current status of the shellfish beds?”
Seibold said the beds were listed as prohibited from harvesting and deferred to Dana Morton, an aquatic biologist with the City’s Environmental and Compliance Department, for an explanation.
“The beds were originally closed due to the salinity in the water,” said Morton. “But back in the mid-’80s, a barge struck the water monitoring device and it wasn’t useable. The state found out it would take about $70,000 to fix it and decided not to repair it.”
Crescimbeni asked commission member Scott Shine to work with the Environmental Quality Division to see what could be done to open the beds.
“I hate to throw a dead squirrel over someone’s fence, but I’d be more than happy to help in anyway I can,” said Shine.
356-2466