Old News Archive

IFW Outdoor Report -- Fisheries Research Section

September 25, 2007 - TRC


The Department of Inland Fisheries and Wildlife has a Fisheries Research Section that is located in Bangor. These fisheries research biologists focus on issues that have statewide significance. The following report details two of the summer research projects conducted by the Department of Inland Fisheries and Wildlife Research Section.


Stream Surveys and the Eastern Brook Trout Joint Venture

The summer of 2007 has been quite an exciting time for Maine streams and wild brook trout! Thanks to the support of the Maine Outdoor Heritage Fund, Trout Unlimited’s Embrace-A-Stream program, and the USDA-Natural Resources Conservation Service (NRCS), we have had five field crews (ten surveyors) stationed in our regional offices dedicated to conducting stream surveys. This effort is allowing us to quickly add trout status and fish habitat information for about 175 watersheds statewide by surveying close to 1200 individual stream sites! This effort greatly increases our knowledge of streams by documenting all fish species encountered, the condition of the stream, potential passage barriers, and the quality of fish habitat. These factors are all vital for sound fisheries management. In order to maintain, improve or restore wild trout fisheries, managers need to have a basic understanding of what species inhabit certain areas, what their relative abundance is, what is the quality of the habitat for trout, and the condition and stability of the stream’s physical aspects.


The importance of accurate species identification

One task we needed to complete in order to get the most out of our statewide brook trout surveying efforts was the compiling of a Identification key for all the freshwater fishes of Maine. Previous guides to the freshwater fish of Maine did not include all of the state’s native species, sometimes focusing on sport fishes at the expense of some minnow species. Additionally, new species introduced into Maine need to be identified so that we can track their spread through the state.

In conjunction with Dave Halliwell of Maine DEP, we compiled a list of native and introduced fish species in Maine. We also included a few species that were not yet known to occur in Maine, but are likely to in the near future due to their proximity to the border. Using several guidebooks for the region (Freshwater Fishes of Northeastern US, Freshwater Fishes of New York, Freshwater Fishes of Canada, Freshwater Fishes of Massachusetts), we compiled an identification key that allows field crews to identify all Maine’s species using just one guide. Additionally, distribution maps for each species in Maine were included, using existing data from lake and stream surveys.

A recent review of Maine’s threatened and endangered species listing required that we review the status and distribution of all native freshwater fish in Maine. In several cases, it was difficult to discern whether a particular species was actually rare, or if it was a lack of survey information that made them appear to be uncommon. Using the species occurrence data from our surveys over the summers of 2007-08, we will be able to accurately and confidently expand our knowledge of many of the less obvious fish species in our state. It will also give us some baseline information on these species, so it might be possible in the future to assess increases or declines in their populations.


The importance of habitat quality

All fish species have habitat preferences where growth and survival are maximized. There is also a range of habitat conditions where individuals can survive and grow, but perhaps not to the best of their abilities. By cataloguing and assessing habitat conditions, we can identify areas or streams where optimal conditions exist, and hence manage those areas for maintaining optimal trout conditions as well as undertake strategies to maintain optimal habitat conditions. Large-scale survey efforts also document what streams may benefit from some habitat ‘tweaking’ to make conditions a little better for wild trout and hence, improve population size or condition.

Fish habitat includes all physical, chemical and biological aspects of stream ecosystems that are vital to sustaining fish populations. This includes everything from water quality (like temperature, pH and dissolved oxygen content) the physical aspects of the stream (such as pools, riffles, and in-stream cover like boulders and large woody debris) and co-habitating species that can be food resources, predators, or competitors. Streams are systems that are constantly fluctuating based upon the continual changes of all aspects always working toward a dynamic balance. Therefore, ‘habitat improvement’ or ‘restoration’ can take on many forms. Most are familiar with typical habitat improvement projects such as improving fish passage, stabilizing eroding stream banks or replanting riparian zones. These are strategies that attempt to mitigate or control certain aspects that contribute to substandard fish habitat. Many times, relatively simple actions, like replanting a riparian zone, can greatly improve stream shading as well as assist with reducing bank erosion and sediment inputs.

Maine’s land use history has left scars on our stream systems. All too often we see the hallmarks of degraded stream channels – overwidened channels with little to no instream structure, such as boulders or pools. These conditions contribute to degraded fish habitat because in an overwidened channel, the water tends to be not as deep and has a greater surface area that is generally less shaded than a properly sized channel. In addition, these streams usually have fewer pools and boulders that provide hiding areas and deep water refuges that trout need to access during stressful times, like the summer months when flows are generally lower and temperatures are higher. Techniques for improving these conditions towards a restored stream system differ depending on such factors as the degree of degradation, the position within the watershed, the surrounding land use, etc. It is important to note, however, that not every degraded stream is a candidate for restoration. Sometimes the stream is so ‘out of whack’ that it simply is not a candidate for restoration because the chance of success, coupled with the high costs involved, is quite low.

Hence, continuing our stream survey and assessment efforts is a high priority. We have to increase our baseline knowledge of our streams and fish habitats in a relatively short period of time. Then we’ll have a much better idea of where existing conditions are optimal for management goals, which areas are candidates for habitat restoration or improvement, or streams that may not offer many opportunities for improving fish habitat or are too unstable for effective restorative efforts.

Merry Gallagher, Research Fishery Biologist and Chip Wick, Fishery Biology Specialist – Streams Research Group


Not According to Plan……

Every time a study is developed, there is always a keen interest in having everything proceed as planned with reams of useful data collected. Unfortunately things don’t always work out that way. Our recent endeavor with radio tagging round whitefish in the Kennebec River is such an example. A little background first though. During last winter an opportunity came about allowing IFW fisheries research staff, FPL Energy biologists, and UMO professor Dr. Stephen Coghlan to collaborate on a telemetry study focusing on habitat use and spawning of round whitefish inhabiting the Kennebec River between Wyman Dam in Bingham downstream to the Williams Dam in Solon. The FPL biologists and IFW biologists have recently teamed on a telemetry study in 2005 of lake trout in Moosehead Lake and another study in 2006 of stocked landlocked salmon and wild brook trout in the Moose River upstream of Brassua Lake. Each of these studies proceeded smoothly and we as a group had high hopes of success in our newest endeavor.

As much of the specifics are not known about the species life history in Maine, a detailed survey of worldwide literature was undertaken. What we found was there is not much in the literature about the species and most of the recent work was from eastern Siberia. I also focused on talking with researchers who have recently performed studies of riverine populations of other whitefish species here in North America. My efforts yielded two contacts, an Idaho Fish and Game biologist who recently studied mountain whitefish and a US Fish and Wildlife Service research biologist in Alaska who studied humpback whitefish. Unfortunately the Idaho study faired poorly, with all of the tagged fish perishing within a month. The study members were stymied as to why this occurred. The researcher in Alaska had excellent success with that study and provided some helpful suggests as we compared surgical techniques and the details of study design.

By spring we had a solid study team, a detailed plan of how the study was to be conducted, and all necessary telemetry equipment, which was generously provided by FPL Energy. In 2006, IFW biologists had sampled the Kennebec River one night with one of the department’s electrofishing boats and collected 16 whitefish, along with good numbers of rainbow trout and landlocked salmon, all of them in about two hours. As we launched the boat in late June our hopes were high that we would be able to quickly collect the 12 whitefish, implant the tags, and release them back to the river. Over the course of the night we collected everything but whitefish! We waited two weeks and returned, this time with the electrofishing raft in order to access pocket water in the shallow riffles. No luck again. A third trip ensued but we focused on a downstream area. Within five minutes of starting our first whitefish was collected! The surgery went flawlessly and the fish quickly swam away when released. Several more hours of sampling yielded no further whitefish. We tracked the tagged fish over the course of a week then had disappointment; the tag started emitting the mortality code. We recovered the tag in a pile of fish bones below a bald eagle’s nest along the river; all under the watchful eyes of two eaglets perched high above in the white pine. Back we went the following week and collected, tagged, and released four more whitefish one evening, hoping that the untimely demise of the first fish was a fluke. We followed these fish for a week. The day of our next collection event, we arrived early to track the fish before dark. One tag was heard down river near the eagle’s nest emitting the mortality code, a second fish was located in its original collection area, and two could not be found. We split up, one group floating the river to check on the one located fish and search for the other two and the other group heading down to the eagle’s nest to collect the tag. After a lot of walking around in 6 inches of water and 2 feet of mud in a shallow cove next to the eagle’s nest the tag was finally found. The two unheard tags were not located and the presumed “alive” fish’s tag was found in a fresh pile of eagle whitewash along the river’s edge. The biologists actually watched the eagle fly from a perch above when they approached the signal! Given our results we decided to halt our study activities for this year and rethink our approach to the study over the winter. Our efforts demonstrated that round whitefish were proving to be much more of a challenge compared to the myriad of other fish species we had collective performed telemetry studies with.

A recent flight by FPL biologists gave them an opportunity to look for the two missing tags. Nothing heard within a mile of the river corridor!

On the positive side, we did learn that:

1. bald eagle’s nesting along this section of river feed on fish in the river (be they dead, injured, or healthy);
2. river water temperature directly influences the use of shallow water habitat by whitefish;

and we also gathered length, weight, and age data was from whitefish as well as the same information from several dozen rainbow trout, landlocked salmon, and brook trout.

Joe Dembeck, Research Fisheries Biologist, Bangor Office.


Submitted by : Mark Latti, DIFW


NOTE - This article reflects the views of the author and not necessarily those of the TRC Alliance Team.