The first European settlers of Plymouth, Massachusetts were probably familiar with Town Creek, the freshwater stream that flows into Plymouth Harbour. In the late 1700's, people began damming the creek in order to capture the power of the industrial stream and the nation's first fish ladders were installed.
Over the years, six dams were built along the creek. These modifications impede the upstream movement of anadromous fishes, those marine species that travel inland in order to spawn. A similar scene exists today in many New England streams along the coastline.
In recent years, state marine fisheries projects have been undertaken to restore Town Creek and remove or modify the upstream blockage of native species to increase movement, including smolt, shad, hagfish, striped bass, and red herring. Forward-looking projects include a new fishway design and electronic monitoring equipment that continuously collects data.
Traditionally, fishways are flat-bottomed concrete, metal, timber structurally reinforced or "ruled" through which fish can swim upstream (often referred to as "technical" fishways). They are limited by the volume of water flowing downstream; if the current is too low, the water is too shallow, and the fish are swimming, and many species cannot swim.
The new structure installed at Town Creek, called Resembling Natural Fishway, is made of natural materials that mimic natural habitats. "It's basically a series of pools with boulders in between," explained Alex Harold, the leader of the monitoring project, and ecologist Silvio Harold of the US Geological Survey. o Conte Turner of the Anadromous Fish Research Center, MA. In contrast to more traditional "technical" designs, which resemble natural fishway V-sections, it is more likely to ensure adequate water depth for fish movement. "Such fishways are becoming more and more popular in Europe," Harold said. "Northeasters want to give it a try. They are relatively cheap and in theory allow more fish to pass upstream. However, no one is doing with our Northeast species." Tested, this is our project."
Once the 75-meter fishway is long, a three-month monitoring program begins. Harold's group needed to collect two types of data: the travel of fish populations through the upper reaches of the fishway, and the movement of water. Ideally, everyone is constantly monitored.
Species selection monitoring is the hostess. In the past, fish were watched by humans through fish counting and other items through technical fishway, which was difficult to do for a long time and human error. In this study, researchers captured and implanted passive integrated transponder (PIT) tags into approximately 400 fish; the tags used behave like electronic tags at highway tollbooths, and detect telemetry antennas and receivers located at Every 10 meters or so along the fishway.
The importance of research that monitors water flow through fishways is also self-evident. Harold's team chose to use HOBO® water level loggers U20-001-01, U20-001-02, U20-001-03, U20-001-04, U20L-01, U20L-02, U20L-04
Start production, calculation process using data. Cigar-shaped, stainless steel Recorders U20-001-01, U20-001-02, U20-001-03, U20-001-04.
Runs for years on a single battery, and allows users to easily specify logging intervals. They monitor water levels 24 hours a day, and the data values are time-stamped so that they can be compared with other data.
Harold's group found the data logger easy to use. He said, "I handed the box to a graduate student and within an hour she had it figured out and was ready. The point-and-click configuration of the logger made it easy to set the desired sampling interval and start time, as well as download and graph the data with a few clicks of the mouse.
Researchers only need two water level loggers U20-001-01, U20-001-02, U20-001-03, U20-001-04. However they deployed three - one in the fishway, below for data verification, and a third 50 meters away from the telemetry receiver housing, barometric compensation. Field site in a highly visible, heavily accessed area, but not a problem with vandalism, researchers placed two-inch loggers U20-001-01, U20-001-02, U20-001-03, U20-001-04 in sections Steel pipes secured pound-for-pound boulders, which were placed in the stream. Weekly data is downloaded to a laptop for graphing and analysis using HOBOware® Pro software, which time stamps data easily with fish count data.
Harold is satisfied with HOBO Recorders U20-001-01, U20-001-02, U20-001-03, U20-001-04
And appreciated for their performance, they are relatively cheap and reusable. He's using them again on a similar project in Connecticut, and hopes to deploy them on another river next spring. He also uses several water level loggers in the laboratory, a flume facility where comprehensive fishways are built and tested. "They are simple to set up and are much easier than hooking up wired sensors and cables and dedicating a computer to data logging," he said.
Overall, the new natural-like fishway performance results for Town Creek are good. Approximately 95 percent of attempts to bridge fishways during the study were successful, suggesting that structures similar to natural fishways could be acceptable for future river and river restoration projects.
