BILOXI -- Mississippi shrimpers had an excellent opening day, a fact that had them pleasantly surprised.

Based on reports from just two of Biloxi’s three shrimp dealers as of July 1, fishermen landed 790,000 pounds of shrimp in the first week. Last year, all three Biloxi shrimp dealers reported total first-week landings of 541,000 pounds of shrimp.

Dave Burrage, professor of marine resources with the Mississippi State University Extension Service, said hot, dry spring weather is considered good for shrimp crops, but the state got the exact opposite this year.

“All of the environmental factors that we normally look towards to sort of do a crystal ball prediction of the shrimp season were against us this year,” Burrage said. “We had a cold, cold winter and a very wet springtime. This was responsible for the late opening, but when the season finally did open, there were good shrimp.”

When shrimp season opened in the state June 18, 368 shrimp boats left port to harvest the crop, up considerably from 250 boats on opening day 2013. That means there was more effort put into this year’s crop, Burrage said.

Rick Burris, shrimp and crab bureau director with the Department of Marine Resources in Gulfport, said the state’s shrimp season generally opens the first two weeks of June. In recent years, it has opened as early as May 25 and as late as June 25.

By state law, Mississippi’s shrimp season opens when brown shrimp reach a size known as “68-count,” meaning 68 shrimp weigh 1 pound.

“We have nine historical shrimp-monitoring stations north and south of the Intercoastal Waterway,” Burris said. “We started sampling in April. We go twice a week and pull a 16-foot trawl for 10 minutes. We measure those samples and determine the count.”

A mathematical formula predicts the date when the shrimp will reach harvest size. Shrimp grow best when water salinity, or saltiness, is greater than 10 parts per thousand and water temperature is 68 degrees or higher.

“When that happens, they can grow really fast,” Burris said. “All the rain we had and the cooler temperatures slowed that down in the spring, but once we started a warming trend, they grew really fast.”

Burrage, who works in Biloxi at the MSU Coastal Research and Extension Center, said most of the shrimp being landed in Mississippi to date have been in the “36/40” and “41/50” size classes, which are larger than the majority caught last year. For example, 36/40 means there are 36 to 40 shrimp per pound.

Another bright spot this year is that prices average at least $1 a pound higher than prices a year ago. As of July 1, the average price for 36/40 shrimp at the factory was $2.70 a pound, up from $1.55 a pound in 2013. Consumers pay dockside prices of $3 to $3.50 a pound for these shrimp.

“Prices are so high because imports are down,” Burrage said. “Imports are mostly pond-raised shrimp, and imports are down because the majority of exporting countries are having problems in their ponds with disease.”

The National Oceanic and Atmospheric Administration reported that in 2013, Mississippi landed 8.8 million pounds of shrimp at a value of $21.8 million.