Planning on taking advantage of Cook Inlet’s minus tides to fill the freezer with razor clams? Already pinpointed the -4.1 tide on May 16 as a time to pack up the family and join the shovel-toting, bucket-carrying crowd on the beach in front of Ninilchik?  

Better change your plans.

As of 12:01 a.m. March 12 and continuing through 11:59 p.m. Dec. 31, the Alaska Department of Fish and Game has closed the beach to clam digging — all clams, not just razor clams — from the north bank of Deep Creek north to a marker approximately 3.2 miles north of Ninilchik River.

“In April 2013, razor clam abundance on Ninilchik Beach was the lowest on record, and surveys conducted during the month showed a substantial decline in abundance of exploitable clams (clams greater than 80 millimeters, 3.14 inches),” announced the department’s Division of Sport Fish in a March 11 press release.

Digger interviews and anecdotal reports also indicated a reduction in razor clam abundance may be occurring all along the inlet’s eastside beaches, though the most pronounced area was Ninilchik. In addition, aerial surveys to estimate digger effort among all eastside Cook Inlet beaches indicated a shift in effort away from Ninilchik to other area beaches.

Other peninsula beaches from the mouth of the Kenai River to the southernmost tip of the Homer Spit remain open, with the bag and possession limit for razor clams set at the first 25 razor clams harvested.

“There still are clams there. The numbers are lower than they have been,” said Carol Kerkvliet, a state fishery biologist, admitting that the Ninilchik closure was “a huge thing.”

Following a storm in 2010, thousands of razor clams washed up along Ninilchik’s shore. The mounds of clams attracted biologists’ attention. Testing indicated the majority of those clams were age two. That, plus the fact that abundance surveys were last done in 2005, drew a closer look at Ninilchik’s clam population. 

Razor clams generally spawn from late July through the end of August. The spawn is broadcast, with fertilization occurring in the water column. Once hatched, the larval state is transport by currents for about 10 weeks before settling out of the water. Depending on a number of environmental conditions such as temperature and wave action, distribution can be patchy.

Research done following the 2010 storm by Ninilchik resident and University of Alaska Fairbanks graduate student Jamie McKeller indicated 90 percent of the clams tested were mature at age two.

“In other words, those clams had already spawned in 2010,” said Kerkvliet. 

With the help of Alaska Pacific University professor Brad Harris and his graduate students, more testing was done in 2011. Sampling indicated 1.7 million clams between Deep Creek and Ninilchik River with 1.5 million of them age 2 and older. 

“So, that was great news,” said Kerkvliet. “The storm event that we saw didn’t decimate the population. That was a huge number of clams.”

The single age class also reflected the lack of large spawning events that would be expected from age of clams found.

“It seems to be some sort of reduced spawning success or settling success is all I can say,” said Kerkvliet.

Abundant surveys conducted in 2013 showed some success; however, the numbers were still low. Harvest data also indicated a decline. 

“If you look at the average clam per digger, from 1977 to 2009, the average was 27 clams per digger. From 2010-2012, it was 15,” said Kerkvliet.

Taken together, the research and survey results led to the department’s closure of the beach for the remainder of the year.

“We’re just being conservative. We need to be right now,” said Kerkvliet, noting that the state would be doing more study of the Ninilchik beaches in April and May. “Now’s the time to just track this population on the Ninilchik beach and now we have an opportunity to track it better and rebuild the population.”

McKibben Jackinsky can be reached at mckibben.jackinsky@homernews.com.