The rapid decline in the numbers of alewife and blueback herring streaming back to the North Shore for the natal rivers and ponds in which they were spawned has scientists along the seaboard extremely concerned about their long term survival. So much so, that in 2006 the Massachusetts Marine Fisheries Commission passed a three year moratorium on the harvest, possession and sale of river herring.
Rivers which were choked with river herring for thousands of years during the last weeks of April and the first of May are now almost devoid of these fish. These declines are not a part of the normal fluctuations you would expect in nature, but are part of a trend that is disturbing in its severity.
There seems to be a crash of numbers that began in 2000. The cause or causes of the decline are suspected but yet unexplained and the possible reasons are hard to evaluate. Phil Brady of the New Bedford Office of the Division of Marine Fisheries said a few streams like Stoney Brook in Brewster and the Town Brook in Plymouth are seeing the return of a good number of fish, but the trend all along the coastline is down.
"A population born in a particular stream are focused on that stream. Conditions particular to that body of water could affect that particular year class success," Brady said. "We have a number of streams where significant improvements have been made in the fishways and spawning waters that have helped, but the recent drop in numbers is alarming."
"When river herring leave the river, they spend the next three to four years in the ocean," he continued. "They do not mix in with other herring, but tend to stay in their own particular river group. Of course there is some overlap, but not all that much. Why Stoney Brook and the Town Brook have remained strong while most of the others have dropped off is a mystery."
The Little River in Gloucester has not been spared from this decline. In 2000 there were an estimated 8,700 fish making their way up the fishway beside the water plant. In 2001 there were 1,800, with 500 in 2002, zero in 2003, and only 150 in 2004. The Essex River counts have followed a similar pattern. In 2001 there were an estimated 15,900 fish passing upstream, but by 2004 there were only about 2,000.
Their are 16 different kinds of fish that return to Massachusetts waters to spawn with the alewife being the most prolific. In the spring of the year when the water gets up to about 50 degrees they move upstream to a headwater pond or a place in the river with very slow-moving water. There the females lay their eggs that are covered with milt by the males. The blueback herring also move upstream to spawn in the spring but they like the water to be a little warmer. They will spawn in faster-moving water, so they do not require a headwater pond. Both of their fry live in the water all summer and then run out to the sea. They live in the ocean for two or three years and then return to their natal river to spawn. While in the ocean they feed on plankton and stay in large schools.
The decline in numbers may be the result of a combination of factors happening in concert, the cumulative effect being disaster. For example, one cause may be the rapidly expanding striper population. With the decline of the numbers of menhaden in the ocean due to over harvesting, these foraging fish have simply moved to the herring.
The second cause may be the increased pressure of large offshore herring fishing operations. Although these boats are fishing for Atlantic herring, a different species, they do scoop up river herring at an alarming rate.
Water removal directly from the rivers for the fresh water needs of surrounding towns and the lowering of the water table from an increasing number of ground wells has lowered the overall water level of our rivers. This means less water on average is flowing down the streams and, as a result, many of the natural waterfalls and drops that the fish used to be able to negotiate have been compromised. Also, the summer water flows are so low that the fry often have a hard time escaping to the ocean when it is their time to go. This is especially true on the Parker River, but is also noted on others.
Massachusetts has been a leader in trying to get anadromous fish back up rivers to their traditional spawning areas. We have almost 150 fishways, the most of any coastal state in the nation. Of course, we need to point out that our earlier history of manufacturing required water power and as a result almost every river in the Commonwealth had at least one dam on it and, in most cases, several. Many of these dams are obsolete, but they stay in place due to history, lack of funds for their removal, or indifference. When combined with the other obstacles these fish face, our efforts have either been too little, too late, or inadequate .
Why is this precipitous decline a problem? As with everything in nature, it is the interconnectedness of it all. The herring need a certain environment to spawn. When that environment is compromised, their numbers decrease. There needs to be a critical mass of them in the ocean to survive. When we wipe out one food source, forage fish will move to another. In this case it is the river herring. When we think we are so smart and increase the number of stripers, for example, sometimes we don't think of what these expanded numbers are going to feed on.
When we allow increased housing and manufacturing we draw more water from the water table and decrease that which flows to the streams. That, in turn, affect the levels of water necessary for these fish to go up and down stream. And, when sewage, discharge, lawn fertilizers, and farm waste are not properly treated, they go into the rivers and streams affecting the spawning populations.
Balance is the key, but achieving that balance takes comprehensive planning we have yet to fully appreciate. The process is so political. The economics of fishing, development, and land use are interconnected and can be abused at almost every level. Maybe we need to be a little more humble about our place in the scheme of things and allow other life forms their due.
