COVID-19: speedboat toll on manatees soars, but large land mammals get a break

Trump administration downlisted manatees to “threatened” status before body count doubled

ST. PETERSBURG, Florida; DAVIS, California––More manatees,  but fewer large land mammals,  appear to have been hit by motor vehicles during the first five months of COVID-19 lockdowns,  studies from four states show.

The bad news for manatees,  reported by the Florida Fish & Wildlife Conservation Commission,  is that 367 manatees have been found dead as of mid-July 2020,  93 of them in Brevard County.

Stretching along the Intercoastal Waterway for 80 miles from Sebastian,  Florida to the Canaveral National Seashore,  Brevard County is home to more than 2,000 manatees and nearly 35,000 registered watercraft,  according to recent estimates.

The combination of manatees and speedboats contributed to causing 88 manatee deaths in Brevard waters during 2019,  fewer than during just the first half of 2020.

COVID-19 keeps wildlife wardens off the water

Decades of population and mortality studies have repeatedly identified collisions with boats as the largest single cause of manatee deaths,  accounting for about 25% of total known mortality overall.  But manatee deaths can spike upward from time to time from causes unrelated to boat traffic,  for instance red tides and abnormal cold snaps.

Currently the Florida Fish & Wildlife Conservation Commission and Save The Manatee Club believe manatee deaths are up in 2020 because more people,  barred from other recreational activities,  are spending more time boating.

Confirmation,  however,  is lacking,  because Florida Wildlife Conservation officers have not been verifying the causes of manatee deaths.

“A lot of officers were not able to go out because of the social distancing and stay-at-home orders. Our partners from the FWC manatee team were not able to go out and recover deceased manatees to determine a cause of death,”  explained Save The Manatee Club representative Cora Berchem to Paul Rivera of WESH 2 News,  serving Orlando and Daytona.

Boat strike count rises five years in a row

Manatee deaths due to boat strikes have trended steadily upward.

“In 2019,  Florida’s boaters set a new record for killing manatees in the state’s waterways,”  observed Florida Phoenix columnist Craig Pittman.

The 2019 boat strike toll of 134 manatees  topped the 2018 record of 122,  “which topped the 2017 record of 108,  which topped the 2016 record of 104,”  Pittman wrote.

“It’s a trend we have seen every year for the past few years,”  confirmed Florida Marine Mammal Pathology Laboratory chief veterinarian Martine de Wit.

De Wit and staff,  Pittman explained,  normally “examine each dead manatee to determine a cause of death.  The Florida Marine Mammal Pathology Laboratory “also spearheads the state’s rescue of injured and ailing manatees,”  Pittman mentioned.

More boaters, but less protection for manatees

An officially endangered species since the first U.S. federal endangered species list was designated in 1967 until 2017,  manatees were downlisted to “threatened”  by the U.S. Fish and Wildlife Service early in the Donald Trump administration.

Though recent counts suggest that the manatee population is growing,  the downlisting came chiefly through lobbying pressure from speedboaters,  speedboat manufacturers,  and shoreline developers.

“In 2015,  Florida had 915,000 registered boats,”  Pittman recounted,  “a number that last year topped 950,000.  That’s more than any other state.”

(See Favor to speedboaters: Trump administration downlists manatees.)

Roadkill drops with stay-at-home orders

Confirming the relationship of traffic volume to wildlife fatalities caused by motor-powered vehicles,  University of California at Davis researchers on June 25,  2020 reported that traffic and collision data collected from California, Idaho and Maine showed declines of from 21% to 56% in known roadkill mortality.

Drops in roadkill deaths of large mammals in all three states coincided with government stay-at-home orders that were in effect from early March to mid-April 2020.

(See 29 ways to avoid hitting animals that may save your life too!)

California,  Idaho,  and Maine otherwise offer extremely different sets of road conditions,  normal traffic volume,  and arrays of wildlife species big enough to cause damage to a car or truck.

“This respite,  if it continued,  could amount to about 5,700 to 13,000 fewer large mammals killed each year in those states alone,  and 50 fewer mountain lion deaths per year in California,”  said University of California at Davis publicist Kat Kerlin.

“The report,  published the U.C. Davis Road Ecology Center website,  is the first evidence that wildlife-vehicle conflict decreased along with reduced travel during the COVID-19 response,”  Kerlin said.

California:  71% drop in traffic brings 21% fewer roadkills of large wildlife

Elaborated U.C. Davis Road Ecology Center director Fraser Shilling,  “There was a statistically significant decline in wildlife deaths on highways in all three states following reductions in traffic this spring.  This has not been the case for any of the previous five years for these three states.  If anything, there is usually an increase [in roadkills] in spring.”

“Traffic on all roads — not just state highways — in California decreased 71% during the study period,”  wrote Kerlin.

“Before stay-at-home orders,  8.4 large wild animals per day were killed by vehicles in California.  After the order, the number fell 21% to 6.6 animals.

Fewer animals mashed in the potato states

“Traffic on all roads in Idaho decreased up to 63% during the study period,”  Kerlin continued.  “Before stay-at-home orders, 8.7 large wild animals were killed daily by vehicles in Idaho.  After the orders,  the number fell 38% to 5.4 animals per day.

“In Maine,  travel on all roads decreased up to 73% during the study period,”  Kerlin summarized.  “Before shelter-in-place directives, 15.2 large wild animals were killed daily on Maine roads. After the order, the number was reduced by nearly half, to 8.4 animals.”

Predictably,  the analysts found,  traffic and roadkills appeared to be rebounding when stay-at-home orders were eased or lifted.

“Given the five- to 10-fold under-reporting of large animals involved in collisions with vehicles and the lack of systematic reporting of smaller animals killed on roads, the positive impacts we report are likely to be just the tip of the iceberg of reduced deaths of wildlife on U.S. roads and highways,” Shilling wrote.

Mentioned Kerlin,  “The report was co-authored by David Waetjen in the U.C. Davis Department of Environmental Science & Policy, with assistance from Road Ecology Center interns Tricia Nguyen, Malak Saleh, Min-Khant Kyaw, Gabrielle Trujillo, Mireya Bejarano and Karla Tapia.”

More traffic does not always mean more roadkills

Somewhat counter-intuitively,  increased traffic and increased roadkills do not always coincide,  especially when increased traffic also brings better designed roads and improvements in vehicle safety.  A comparison of roadkill counts done using similar methods in Greenville County,  North Carolina in 1937 and in Mentor,  Ohio,  from 1993 to 2006 showed that the North Carolina drivers hit 30 times more animals relative to miles traveled.

As the two communities were demographically similar and hosted similar wildlife,  improved road quality,  driver education and experience,  and better tires and brakes appeared to account for the sharply contrasting findings.

Roadkills also dropped steeply in Mentor over the 13-year duration of the study,  coinciding with maturing urban tree cover that enabled squirrels,  in particular,  to cross streets by leaping from branch to branch instead of running through traffic.

(See Roadkill counts,  1937-2006,  showed longterm decline.)

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