Milford Harbor is chocked full of menhaden, or bunker, drawing spectators downtown to watch as the fish churn the waters and occasionally break the surface.

Jason Jadach, owner of Bobby J’s Bait and Tackle in Milford, estimated that about three quarters of the harbor is filled with millions of bunker. He said the numbers are higher than they’ve been in recent years, but not anything unusual.

Joseph Gilbert, owner of Briarpatch Shellfish Company, has spent years observing menhaden in the course of his work.

“This is just a good year for them,” Gilbert said, adding that there have been huge numbers like this in the past.

Increased numbers in Milford Harbor now may be due to several factors, such as the bigger fish that eat them, like bluefish and striped bass, are still swimming farther out in the Sound and the bunker are relatively safe from them in the harbor.

Water temperatures and commercial fishing restrictions on menhaden in other states, which have led to an increase in menhaden numbers overall, also play a role, Jadach speculated.

Kurt Gottschall, fisheries biologist with the Department of Energy and Environmental Protection (DEEP), agreed restrictions in other states may be a factor in Connecticut. Large numbers of menhaden have been reported in Milford, Stratford, New Haven, Stamford, Greenwich and other coastal communities.

But, Gottschall said, “This is a very, very normal event. There is nothing unusual about having this many menhaden around.”

A few years ago, there were so many “you could almost walk across the water on them,” he added.

Milford residents may continue seeing the swarming bunker through October, unless the bluefish and striped bass realize there’s a ready supply of chow in the harbor and start to come in “like clockwork,” running laps in the morning and afternoon to feed, according to Jadach.

While the teeming bunker have attracted anglers as well as onlookers in Milford, fishermen aren’t reeling them in for dinner.

“You wouldn’t eat bunker,” said Ralph Petitti, a local fisherman. “They’re too bony and oily. They don’t taste good. People use them for bait.”

Bunker are also used for fish meal and for their omega 3s, leading to overfishing in the past along the East Coast of the United States, and efforts by groups like Menhaden Defenders to push legislation that has increased restrictions on commercial fishing of menhaden.

According to Menhaden Defenders, menhaden are reduced to fish oil for human fish oil supplements and for use in pet foods, poultry and swine feed, plus other consumer products.

The group says that menhaden “are, without a doubt, the single most important fish in the Atlantic Ocean and the Gulf of Mexico.”

Filter feeders, menhaden feed on algae and they swim in large schools.

“The primary job of this species is to convert plankton and algae into a package that predators can easily eat,” according to Menhaden Defenders. “And the predators are numerous, including birds, striped bass, tuna, sharks, seals, dolphins and whales. Without abundant menhaden along our coastlines, the ocean wildlife will suffer.”

Menhaden are an extremely important part of the food chain, said Tom Andersen, director of communications for the Connecticut Audubon Society.

“They are probably the most common prey of the state's ospreys,” Andersen said. “The rebound in the osprey population is probably partly due to the abundance of menhaden.”

Menhaden are also typically the fish that die in late-summer fish kills in the Sound's harbors. They get chased by bluefish into the shallows where dissolved oxygen is low and then suffocate and get caught when the tide goes out. It's a phenomenon that has been noted in the area since the 1600s, Andersen said.

At the DEEP, Gottschall said some small fish kills by hypoxia have been reported this year, and he wouldn’t be surprised if there are more because of the large number of menhaden.

Local fisherman see the big schools of bunker as a promise of things to come. Lots of bunker here now will likely mean good fishing in September.

“It should make for a really good fall run of fishing,” said Jadach.