BELIEVING IN THE OCEAN
“Even the upper end of the river believes in the ocean.” William Stafford
As the planet’s axis shifts bringing spring to the Northern Hemisphere, phytoplankton begins to bloom in the Gulf of Maine. The phytoplankton bloom grows in response to the increasing strength of the sunlight, and a hatch of myriad species of zooplankton takes place. Copepods, fish larvae, shellfish larvae and tiny shrimp all graze ravenously on the chlorophyll producing phytoplankton. By mid April, the Gulf of Maine has become a huge cauldron supporting a planktonic stew that in turn serves as the basis for a far-reaching web of life – a web that includes the trans-oceanic movements of whales, reaches into the air in the forms of birds, and travels far up the rivers flowing to the continental shelf – for the arrival of spring to the Gulf of Maine also triggers the migration of millions of river herring to the coast of New England, where they will begin a journey up their natal rivers and streams.
The flow of energy that begins with the conversion of sunlight into chlorophyll by phytoplankton moves through the food chain roughly as follows:
10,000 pounds of phytoplankton equals –
1000 pounds of zooplankton equals –
100 pounds of herring equals –
1 pound of seal.
A single egg bearing herring, swimming up into a river system to spawn, represents 50 to 100 pounds of phytoplankton moving inland from the sea. The rivers, for their part, provide the freshwater plankton required for the initial growth of the juvenile herring, and also carry nutrient rich sediments from the land to the estuaries and the ocean where they nourish the marine phytoplankton. This is a cycle of energy transfer that has worked well for all involved for eons.
Each female herring will carry between 60,000 and 100,000 eggs depending on her size and age. Herring return to their rivers after spending 3 to 5 years at sea feeding on plankton. And a herring, after its initial run, can spawn for multiple years while living as long as ten years. The older and larger female herring will carry more eggs than the young herring that are on their first spawning run after three years at sea.
There are two types of herring that return to our New England streams; the alewife and the blueback.
The alewife herring has evolved to spawn in headwater ponds and lakes where, after the spawn in April or May, its eggs eventually hatch and begin life feeding on freshwater plankton. Juvenile alewife herring can be ready to begin dropping out of the ponds and down the rivers toward tidal estuaries by the end of June or early July. The blueback herring, unlike the alewife, spawns in moving water and is not dependent upon being able to access ponds. In part because of their independence from ponds for spawning, and because of their tolerance of warmer temperatures, blueback herring have a wider range than alewife herring.
Alewife, on the other hand, are more prolific, and as such they were deemed to be more valuable by the townspeople of New England – who didn’t hesitate to encourage alewife (where ever it was feasible) by digging ditches between the headwaters of streams to nearby ponds.
The early English settlers valued alewife herring enough to begin enacting laws for their protection shortly after dams began to be erected on streams for the purpose of powering mills. According to one account, the first dam that was built in Massachusetts Bay Colony was erected in 1694 on Indian Head Brook at the site of an old beaver dam in what is now the town of Hanson, Mass. Its original purpose was to power a sawmill. By 1705 there was enough concern about the passage of alewife herring up Indian Head Brook to their spawning waters at Indian Head Pond that the first colonial ordinance for protecting alewife was passed.
Recently, I visited Wampatuck Pond in Hanson at the site of the dam on Indian Head Brook that spurred the creation of the first law protecting fish passage. Massachusetts Route 14 passes over the old granite block dam that creates the impoundment known as Wampatuck Pond, now known more commonly as Town Hall Pond. Behind the dam there is a replica mill house and a replica paddle wheel all built to commemorate and to help relate the history of the mill that once stood in that place. What is glaringly absent is any fish way through this relic dam.
For millennia the alewife herring had made the long swim up the North River to the Indian Head River, and then up Indian Head Brook to Indian Head Pond to spawn. These were the herring that had given rise to the first colony wide protective fisheries laws, and now they are not only extinct, but also forgotten. At Wampatuck Pond, the herring have been reduced to being a footnote in the story of a mill that in the grander scheme of things served a purpose for only the blink of an eye.
A few weeks after my trip to Wampatuck Pond, I met with Samantha Wood, Sara Grady and Nick Wildman at the Luddam’s Ford Dam on the Indian Head River. Samantha is the Executive Director of the North and South Rivers Watershed Association. Sara works for Mass Bays and serves as the ecologist for NSRWA. Nick is the Priority Projects Coordinator of the Mass. Div. of Ecological Restoration. The Luddams Ford Dam is the first dam above the head of tide on the Indian Head River, and we had convened to check on the operation of the ancient fish ladder that, for nearly 100 years, had been the sole means for diadromous fish to move upstream in the Indian Head system.
While some herring could be seen in the river, they seemed reluctant to expend the energy required to battle the heavy flow that was coming over the spillway of the dam. Our task was to inspect the fish way to get a better understanding of how it worked (or didn’t), and, if possible, to try and find a way to improve its function.
To get to the fish ladder we had to crab walk along the top of the spillway, all of the while fighting to keep from being swept off the dam by the current. A week before, Phil Lofgren, who serves as a herring warden in Weymouth, Mass., had shown me this route across the top of the dam to the ladder. Phil had cleaned debris from the ladder the previous spring and he was now interested in adjusting its baffles to get better fish passage. As things turned out, Phil was not able to make the meeting on this particular day, and we were on our own. With no clear idea of what needed to be done, we headed out across the spillway while trying not to look at the water crashing on the rocks below.
As we were working our way cautiously along the top of the spillway, Nick asked, “Why don’t we just walk along the backside of the dam?” I had assumed that the sediments that had collected almost to the lip of the dam would be like quicksand; a soft death trap that one would sink into, never to be seen again. I was about to warn Nick of my fear when he stepped over the lip of the spillway and began walking through the knee-deep water. “It’s a firm bottom.” Nick announced, and then he proceeded to walk over to where the water entered the fish ladder.
It turns out that this phenomenon of heavier sediments, like sand, settling out and building up behind the spillways of old dams is common enough that Nick had seen it before. He explained that the lighter sediments that would build up a muck bottom get pushed over the dam by flood events, while the heavier sand remains, eventually collecting to the lip of the spillway.
Our examination of the fish ladder showed only that the herring weren’t using it, at least, not on that day.
The following week I took a ride over to Third Herring Brook, another tributary of the North, where the NSRWA and the Mass. Div. of Ecological Restoration (under Nick Wildman’s guidance) are working with the Cardinal Cushing Center, the owners of Tack Factory Pond Dam, to remove that barrier to fish passage from the brook. In the past, removal of the dam has met with resistance from people abutting the small pond behind the dam.
Ten years ago, NSRWA and Mass Riverways (now Mass. DER) were making the first attempt to remove dams for fish passage in the Commonwealth. The focus of this effort was on two dams, Mill Pond Dam and Tack Factory Pond Dam. As with many small streams in Massachusetts, Third Herring Brook marks the boundary between two towns, in this case, the towns of Hanover and Norwell. While Hanover permitted the removal of Mill Pond Dam, abutters to Mill Pond Dam convinced the Town of Norwell to deny a permit.
Norwell’s refusal was a crushing blow. The funds for the removal of the dam had to be returned to American Rivers, and money spent on studies and engineering was, for all practical purposes, lost.
Eventually, the Mill Pond Dam would breach in a flood and most of the pond, so hotly defended by by the abutters (who did not own the dam), drained out. Third Herring Brook, it seems, couldn’t wait for permission to heal itself.
Now NSRWA – with added support from TU/NOAA, Greater Boston Trout Unlimited, and the Sea Run Brook Trout Coalition – is moving forward with the dam’s owners, the Cardinal Cushing Center with the effort to remove Tack Factory Dam.The breaching of Mill Pond Dam upstream of Tack Factory, along with a crash in herring numbers and a changing public attitude about dam removal are combining to diminish resistance to undoing the harm done by these crumbling edifices. The remains of the washed out Mill Pond Dam will be removed this fall (2014), and Tack Factory Pond Dam is on track for sometime in 2015.
When I arrived at Third Herring, the pools below the River Street Bridge contained pods of herring that were making their way upstream. Their journey would end at Tack Factory Pond Dam, a short distance above River Street. Above Tack Factory Dam there are ten miles of stream and tributaries that have not seen herring in centuries.
Because herring populations are limited by the amount of plankton available for juveniles in their freshwater spawning areas, increasing the number of stream miles that herring can use to spawn, will in time, increase the herring population proportionally. As with larger river systems, like the Kennebec River in Maine, when more dams are removed from the North River’s system, the herring runs will swell.
But, dams and degraded rivers are not the only threats that river herring face. The demand for all species of marine forage fish has increased dramatically as fish farming has become a primary source of food fish for humans. According to Dr. Andy Danylchuk at the University of Mass. Amherst, fish farming now accounts for half of all of the fish that we eat. And, some of the more popular farmed fish, like salmon, are grossly inefficient users of natural resources.
The massive mid-water trawlers that scoop the forage fish, that make up the fish pellets that are fed to farmed salmon, can’t discriminate between river herring and sea herring while they are making a haul that can pull aboard as much as 500,000 pounds of fish at a time.
If we were to compute the number of herring, or menhaden that it takes to grow a single farmed salmon (remember the number of herring to grow a pound of seal), and then add in all of the energy consumed to harvest the herring or menhaden and convert them into fish pellets, we can see that farming salmon is so ridiculously inefficient and unsustainable that it will, or should, disappear in the near future just as a matter of the economics involved.
In contrast, wild salmon are a model of efficiency. They go out to sea and do all of the work that the trawlers and processing plants do without using fossil fuels or emitting greenhouse gases. Wild Atlantic salmon travel to Greenland, where along with whales and numerous other sea creatures, they fatten on an abundance of krill, a small animal much lower on the food chain, and therefore a much more efficient source of forage than herring.
The real irony here is that the river herring and the salmon both require only one thing of us – healthy, unfettered rivers and streams. We need to believe in the ocean as our rivers do.