Shad population in the Connecticut River healthy but smaller

For decades American shad have been one of Western Massachusetts’ signature fish, flooding the Connecticut River in the spring when they head upstream from the Atlantic Ocean to spawn.

This is a story about their present and future.

During their trip, they come up against the Holyoke Dam. To continue on, multiple times a day fish swim into a giant tank at the Holyoke Fishway on the Connecticut River — sometimes by the hundreds, sometimes by the handfuls — and get a lift over the obstacle.

While all manner of fish hitch a ride, those tanks mostly fill with shad. During their trip up over the dam, the fish are counted before they continue on their way.

Since 1980, the annual shad count in the Connecticut River has averaged 318,000, but the fish can be fickle. Last year’s total of 190,074 was the lowest in more than a decade, while 2017 was a peak year with 536,607.

“The Connecticut River has one of the healthier shad populations in the east coast but it is not as close to what we want,” said Ken Sprankle, a U.S. Fish and Wildlife biologist and expert on the Connecticut River. “We want to be passing 680,000 shad in Holyoke.”

Over the past four years, the population shows some declines with 314,361 counted in 2019, 262,244 recorded in 2020 and 237,306 counted in 2021, said Sierra Humiston, the Holyoke Gas & Electric Fishway and communications coordinator.

“It is cyclical. They are a boom and bust species,” Humiston said.

Experts point to several different factors possibly influencing the size of the river’s shad population. But one of concern is a changing climate that warms the Connecticut River, shortening the shad’s spawning season.

The shad are vital for the Connecticut River. They are a great recreation fish for local anglers and there are a few who catch them commercially, so it is important to keep close track of the health of the population, Sprankle said.

‘Important they become dinner’

The juvenile shad, which summer in the river and grow to three to four inches before they head to the ocean, have a “tremendous biomass” and are eaten by bald eagles, osprey and many other fish and animals that live in and along the river, Sprankle said.

“It is important they become dinner,” Sprankle said. “These fish provide a tremendous forage base in the Atlantic Ocean and lots of things should be eating them.”

Because American shad start spawning at 4 to 6 years old, it is hard to know why there were fewer shad counted in 2022. Something could have eaten a lot of the eggs or they could have been destroyed by a cold snap or other environmental factor years earlier, Sprankle said.

“It has been bouncing around quite a bit,” he said.

A 5-year-old female generally will release 310,000 eggs and the male fish will then fertilize them. The eggs hatch quickly — usually between 24 hours and three days depending on the temperatures — and the fish live on yolk sacks for a couple of weeks before they start feeding. They spend the summer in the river and start migrating between July and August, when they are three to four inches long, with the latest moving to the ocean in early November, Sprankle said.

The female releases a large number of eggs because many don’t hatch and the survival rate for juveniles is relatively low. Those that do make it stay in the ocean until they mature and are ready to return to their birthplace to spawn, he said.

The parents do not stay with the eggs or the young, and the female fish do not drop all their eggs in one spot, continuing to swim upstream dropping between 40,000 and 50,000 eggs a day, he said.

“They spread it out, we call it bet-hedging. Maybe the first spot isn’t a great spot maybe another spot has a higher survival rate,” Sprankle said.

The fish will spawn as far north as Bellows Falls, Vermont, but to do that, they have to get over dams in Holyoke, Turners Falls and in Vernon, Vermont. That is why the Holyoke Gas & Electric’s Robert Barrett Fishway — which is more an underwater elevator than a ladder — is so vital.

The Holyoke Dam was originally completed in 1900 and the first elevator, installed in 1955, was essentially a bucket that workers would raise by a cable and then carry to the other side of the dam and dump out the fish. In the first year, 4,899 shad were recorded as being moved through the ladder, said Kate Sullivan Craven, marketing director for Holyoke Gas & Electric.

Over the years, the system has been improved. In 2016, it was upgraded when there was a major modernization of the hydroelectric equipment at the dam. There are now two elevators that carry the fish to a 300-foot-long flume, which they swim through to reach the other side of the dam, she said.

People can even visit the fishway to learn about the river and its fish, watch the elevator rise and see the shad and other migratory species swim through the flume. The tour also teaches people about the dam, which generates about 65% of the energy provided through the municipally run gas and electric company.

The Robert E. Barrett Fishway reopened to the public this year, after being closed completely in 2020 and 2021 because of the COVID-19 pandemic. Last year, it was only open to groups. But this year, it has been busy with more than 3,000 people visiting by late May, Sullivan Craven said.

One fish, two fish

The fishway at the Holyoke Dam also collects an enormous amount of annual data about the fish on the Connecticut River and employees share the information and partner with at least seven different agencies, such as U.S. Fisheries and Wildlife Service, National Oceanic Atmospheric Association, the Connecticut River Conservancy and the federal S.O. Conte Anadromous Fish Research Laboratory, she said.

Holyoke Community College interns count every fish as they swim through the flume to freedom. They remove some from the tank daily to record their length, weight, sex and to take a scale sample.

“The scales are like rings on the tree and they can give us the age and a lot of information,” Sullivan Craven said.

The shad are not the only fish that swim through the ladder and all those species are counted as well. While shad are by far the most abundant, in 2022 the ladder also recorded 283 blueback herring, 311 striped bass, 22,233 sea lamprey, 63 gizzard shad and 20 shortnose sturgeon, which are endangered. The last time Atlantic salmon, which are now believed to be extinct from the river, were recorded at the fish lift was in 2019. At that time, three passed through.

Interns also make note of any other fish which end up in the ladder such as small mouth bass, carp, catfish, blue gills and pumpkin seeds. Those fish are not spawning but go for “a little ride” if they swim into the tank, Craven Sullivan said.

“Basically if there is data we collect it,” she said.

Shrinking fish size

During the recent Holyoke Gas & Electric Shad Derby held at the Fishway, anglers said the size of the shad has been smaller than usual in the past few seasons.

“I have caught a few that are 3.6, 3.5 pounds but we used to catch 4-pounders like nothing,” said Robert Layton, of Granby, who has participated in close to 50 tournaments and won twice.

Others agreed. Participants’ theories ranged from river current changes and commercial fishing to climate change and pollution.

“Everyone has a different idea why the fish are smaller,” Layton said.

The world record for the largest American shad ever caught was set in 1986 when an 11-pound, 4-ounce fish was hooked in South Hadley.

The samples taken from the Holyoke Fishway confirm what anglers are seeing. The reason is simply that the fish swimming up the Connecticut are first-time spawners and are young, Sprankle said.

Of all the fish spawning in the river, just 5-7% are returning for a second season. Those fish are 7 to 9 years old and are larger. They are also much desired because an older female will produce an average of 500,000 eggs, some 190,000 more than their younger sisters, he said.

“We are finding the fish are smaller. It has happened over a long period of time. We have the data from the 1970s to 1980s and there is a decline of fish of massive sizes and a loss of older fish,” Sprankle said. “When I was a kid, I did not shad fish and I caught a 6-pound fish; that is how abundant they were.”

A two-way journey

Biologists don’t fully understand the reason fish are not returning to spawn again, but they realize they must concentrate more on developing systems to allow fish to swim downstream after they finish their journey. In the past, the focus has been on making sure they get over the dams while going upstream, he said.

“We have taken some positive steps but we haven’t seen the response,” Sprankle said. “I was hoping by now we would see a response in the repeat spawners.”

The improvements were also designed to help the population of the shortnosed sturgeon, but officials have not seen much of a shift in that population either, Sprankle said.

As part of its 2016 project to upgrade the equipment, Holyoke Gas & Electric retrofitted the downstream bypass gate that now ensures the fish can pass by the dam at all depths of the river, Humiston said.

Improvements also continue to be needed at dams to ensure fish do not dead-end when they are going upstream and can reach historic spawning grounds in northern Massachusetts and Vermont, Sprankle said.

Vernon, Vermont, has a fish ladder that is effective, but the ladder at Turners Falls is now being replaced with a lift like Holyoke’s as part of the licensing agreement with the Federal Regulatory Energy Commission. That ladder, developed by U.S. Fish and Wildlife in the 1980s, just wasn’t the right design and never worked well, Sprankle said.

All is not lost if shad cannot get upriver, since a female will still release her eggs if she hits a barrier. The problem is many end up in the same place so the chance of survival is lower, he said.

A persistent species

Over the decades, the water quality of the Connecticut River has improved as factories no longer dump chemicals in the water and wastewater treatment plants — especially in cities such as Springfield, Chicopee and Holyoke — have spent hundreds of millions of dollars on upgrades to ensure less untreated waste is being dumped in the river.

Shad have never been dissuaded by water pollution. Probably one of the biggest problems now has to do with the fact that estrogen from women who take birth control pills cannot be filtered out and can impact sexual development of fish. There are also concerns about microplastics, he said.

“Shad have always persisted,” Sprankle said. “Shad was here for the worst humanity could throw at them. You are talking about the worst quality of water.”

But climate change is a very real factor for the shad and other migrating fish since the season is changing and shortening, he said.

With a smaller snowpack, the water is warming earlier. Migration is still starting in early April, but instead of ending in July, most of the season is ending in mid-June, Sprankle said.

“That is concerning to us,” he said. It isn’t good for the population if the spawning season is reduced from 35 to some 30 days because it becomes more intense and there may be fewer times females can release their eggs.

Higher water temperatures also sap the shads’ energy. Biologists figure 60 degrees is an ideal temperature and when it reaches 68 degrees, it is stressful for the fish.

The department is studying it but results are not conclusive. Preliminary data shows increased temperatures have the potential to raise natural mortality so there will be fewer of everything in the water, he said.

While the shad population in the Connecticut River remains healthy, there is still plenty of work to do. Over the past few years the population hasn’t hit the 40-year average of 318,000 a year, and the last time it was exceeded was in 2017 with 536,670 passing through the Holyoke Fishway, Sprankle said.

Average isn’t what experts want. They feel conservatively the river could support an annual spawning population of 680,000, but the only year when the total exceeded that was in 1992 when the total number of shad counted at the fishway was 721,336, he said.

There are other rivers where the shad populations have dropped dramatically or barely exist. Biologists are sharing spawning fish from the Connecticut River to try to seed those locations.

They have giant tank trucks that hold 1,000 gallons of water rigged with a system that will make it circulate continually. They have loaded them with 80-100 shad from the Connecticut River and stock those fish in rivers in places like Pawtucket and Woonsocket, Rhode Island, in the hopes that those fish will release eggs that will hatch and their babies will return in four to five years to spawn.

“Some issues are not unique to the Connecticut River. It has one of the healthier shad populations in the east coast but we want it to be much better,” Sprankle said.