Whitefishin’

LWF_Umsaskis_7_14As part of our ongoing fisheries monitoring work, we’ve been visiting a lot of lake whitefish waters in the region this summer. Lake whitefish are an often overlooked sportfish in northern Maine, but they can provide excellent angling opportunity in some of our more pristine lakes. The species has declined considerably over the past 50-100 years, so it’s important that we keep track of our whitefish populations.

One interesting fact about lake whitefish is that the species occurs in both normal and dwarf forms. While normal whitefish can grow to sizes of 18-20 inches or larger and live for more than 25 years, the dwarf form grows to a much smaller size, matures at a young age and has a very short life span. Some lakes have both dwarf and normal whitefish, while others have only one form. While they are still generally considered the same species, there is evidence to suggest that the dwarf and normal whitefish have become reproductively isolated over time such that we may be witnessing the formation of two distinct species. Interesting stuff!

Here are a couple of photos of whitefish we’ve recently sampled from the Allagash drainage.

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Public Hearing in Fort Kent on July 21

Inland Fisheries and Wildlife will hold the first of four public hearings in Fort Kent on July 21 to receive public comment on proposed changes to ice and open water fishing rules.  The proposed changes would take effect January 1, 2015.  Anyone unable to attend a public hearing may submit written comments on any of the proposals.

Location and time:  July 21, 2014, 6:30 PM at Fort Kent Community High School; 84 Pleasant Street, Fort Kent

The complete list of all hearings found here.

The complete package of 2015 proposals can be viewed here.

What are those little black spots?

“What are the black spots on the trout I just caught” is the most common question we hear this time of year. As soon as June arrives and anglers all over the State hit their favorite fishing hole, trout with “those black specks” start showing up. Here is some good information from former IF&W biologists to answer common questions such as: What is it? What causes it? Can I eat it?

“Black spot disease” or “black grub” in trout is caused by a trematode worm in its larval, or immature, stage. The tell-tale sign is small, sand-grain sized black spots on trout and other fishes. The level of infestation can range from just a few, barely noticeable spots to heavy with the fish nearly covered as in the large trout in the photo.

Heavy (larger trout) and low black spot infestation in brook trout from a northern Maine pond.

Heavy (larger trout) and low black spot infestation in brook trout from a northern Maine pond.

The species of trematode worm that causes black spot uses snails and fish as intermediate hosts in their immature stages.  Loons are the most common host for the adult worm living in the bird’s mouth and producing eggs that are eventually passed through the loon’s gut and into the water.  The eggs mature and produce ciliated miracidia that penetrate snails and other molluscs (the first intermediate host).  The worm develops into cercariae within the snail. As trout ingest and digest infected snails, cercariae become mobile, penetrating tissues of the second intermediate host (the trout). The mechanical damage caused by this mobile stage causes hemorrhaging.  Once the cercariae become stationary in the fish’s skin it produces the visible scarring in a slightly raised black spot.  The cycle is completed when a loon ingests an infected fish.

Anglers are usually most interested in whether trout with black spot are edible.  Proper cooking kills the parasite and renders the fish completely safe to eat.

Retired IF&W biologist Ron Brokaw wrote this 1972 article for Maine Fish and Game magazine.  Maine IF&W’s Fish Health Laboratory also released a more recent report on black spot as well.

 

 

Recent stocking of brook trout in Aroostook

As a result of extra trout in our hatchery system, the following waters were recently stocked with brook trout that average about 10 inches in length.  Current cool, rainy weather should prolong our excellent spring fishing.

Nickerson Lake, New Limerick, 750 brook trout, June 17

Hanson Brook Lake, Presque Isle, 500 brook trout, June 18

Conroy Lake, Monticello, 450 brook trout, June 18

Limestone Stream, Limestone at Community Pond, 250 brook trout, June 18

All of these waters have public access facilities available.

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Smallmouth Bass Documented in another Aroostook Water

We recently documented yet another invasive fish population in Aroostook County that is likely the result of anglers moving live fish from one water to another.  District Game Warden Ryan Fitzpatrick was contacted by an angler this spring who had reportedly caught a 15 inch smallmouth bass.  Warden Fitzpatrick received the fish and delivered it to the Ashland Headquarters.  I inspected the fish and interviewed the angler by phone.  The fish was caught at Trafton Lake in Limestone and another larger fish was also caught in the same location.  We believe this was an illegal introduction.

Smallmouth bass from Durepo Lake, 2004

Smallmouth bass from Durepo Lake, 2004

Moving fish from one water to another can be very damaging ecologically, and often results in the permanent loss of important native fish populations.  It is also highly illegal.  Introducing any fish species or possessing or transporting any live fish (except baitfish) without a permit is a Class E crime punishable by a fine of up to $10,000 and may result in the suspension of all Department licenses and permits.  Should anyone have information related to this recent illegal introduction at Trafton Lake please call Operation Game Thief at 1-800-ALERT-US.

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Photo of smallmouth bass caught at Trafton Lake, Limestone, May 2014.

Trafton Lake is a reservoir created by a dam built in 1969 for recreation and flood control.  For many years, Trafton supported excellent trout fishing with fish of large size commonly caught.  Personally, some of my best fishing while growing up was at Trafton Lake, just off the boat landing in the shallow end of the lake.  My friend and I spent hours in the mid 1980s casting lures and flies catching beautiful trout.  This fishery, and many others, are in jeopardy of being lost forever.

Eliminating or controlling invasive fish once they become established is difficult, costly, and only successful under certain conditions. Another reservoir nearby, Durepo Lake, was the subject of a high-profile illegal introduction of largemouth bass back in 2001.  IF&W responded quickly and reclaimed the lake in October of that same year, successfully removing the new species.  The very next year someone introduced smallmouth bass.  IF&W made the decision to not redo the expensive treatment of rotenone to combat the latest illegal activity.  With this latest news from Trafton Lake, we are reassessing the feasibility of controlling or eliminating both bass populations on the fringe of wild brook trout country.

New Fish Tagging Study on the St. John River

Smallmouth bass and muskellunge have been a huge topic of conversation among anglers in the St. John River watershed since their invasion in recent decades, but as biologists we often lack the specific data needed to answer questions about these fish populations and where they are headed.

IMG_0907With that in mind, we’re initiating a long term tagging study of bass and muskies in the St. John.  Individually numbered t-bar anchor tags are being placed in fish captured throughout the river.  We hope that anglers will report tagged fish they catch and help provide the data we need to answer questions about fish movement, survival and growth.

FloyTagThe small, tubular plastic tags are located on the outside of the fish’s body, just below the dorsal fin.  Each tag has an ID number printed on one side, and the phone number to our office on the other side.

IMG_0883crWhen we tag a fish, we record its length, weight, age, and where it was caught.  When the fish is recaptured, we can then compare that same information with data collected at the time of tagging.

IMG_0918crFor instance, say we catch a 3 year old, 10 inch long bass in the river in Frenchville this summer, and three years later an angler catches that same tagged bass at the boat launch in Fort Kent and it’s 15 inches long.  We know that the fish survived to age 6, grew 5 inches in 3 years, and migrated upstream more than 12 miles from where it was tagged.  That information is very valuable in itself, but when combined with data from hundreds of tagged fish, it can be extremely useful.

IMG_0914crIf you fish for muskies and bass in the St. John, please keep an eye out for tagged fish, and keep track of the following things:

Location of catch

Tag number and color

Fish length

Was fish kept or released? 

IMG_0911You can email these details to jeremiah.wood@maine.gov or visit the About Us page for more contact information.

Click here for a link to our informational flyer on the tag study.

When you report a tagged fish, we’re also happy to let you know the history of the fish you caught.

Hope to see you on the river!

Aroostook Fisheries Update: 6/6/14

Spring brook trout stocking has pretty well wrapped up in Aroostook County, and anglers have reported good fishing in many of our stocked waters.

Click here for a list of waters that were stocked this spring.

Meanwhile, we’ve begun to evaluate some of our trout ponds that are stocked with fingerling fish in the fall.  These ponds are stocked with smaller fish with the expectation that they will grow to catchable size in the year or two following stocking.

Here’s a picture of a nice brook trout we caught yesterday from a fall fingerling stocked pond.

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The fishing’s been hot lately, and we’ve been chasing fish all over the northern tip of the state.  We’ll do our best to keep you updated with the latest on Aroostook Fisheries, including a new fish tagging study that should be underway soon.  Stay tuned!

Eagle Lake Anglers Encouraged to Harvest Salmon

Anglers fishing Eagle Lake this upcoming season are encouraged to keep legal salmon they catch in the 12-16″ range. The current rule allows three salmon per angler per day to be kept; salmon must be at least 12 inches in length.  We continue to be concerned with high numbers of small, slow growing salmon at Eagle Lake, so increasing harvest is a first step in improving the salmon fishery. Reducing salmon numbers at a time of high smelt abundance should result in better salmon growth and fewer, but larger, salmon available to anglers.

You should see an informational flyer (Eagle Lake 2014) posted this summer at boat launches, the Town office, and other locations around Eagle Lake encouraging anglers to keep their salmon catch. EagleLake_map_5_14

Eagle Lake Overview

Eagle Lake is one of the focal waters of the Fish River Chain of lakes in northeast Aroostook County. At 5,580 acres, it is the third largest water in the Chain.  Eagle has diverse fish habitat that is ideal for salmonid sport fish.  Brook trout, salmon, lake trout (togue), burbot (cusk), and rainbow smelt all support important fisheries at Eagle, and smelt provide the main forage for salmon and togue.

History

Togue, brook trout, and lake whitefish historically made up the fishery in Eagle, but things changed dramatically with the introduction of salmon and smelt in the late 1800s.  The Fish River and its chain of lakes became renowned for tremendous salmon fishing throughout the 20th century, at times producing very large fish.  In recent years, Eagle has become better known for its ability to grow and support large togue, while other lakes have been more noted for salmon fishing.

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Salmon caught at Eagle Lake in 2004

 

Eagle Lake Salmon Fishery

For more than 20 years now, salmon fishing at Eagle Lake has seen a few highs, but mostly lows.  It seemed efforts by biologists to improve salmon growth was always met with some measurable but very short lived success.  You name it and it happened at Eagle Lake – from variable survival of hatchery salmon and togue in the 1980s, a highly variable smelt population, an ever increasing wild salmon population and an explosion in wild togue in 2004 – there always seemed to be an issue that pushed the balance of predator/prey, (in this case salmon/smelt) out of whack and resulted in small, thin salmon.  Around 2000-2001, for example, smelt were so few in number that a hydroacoustic survey found the lowest smelt density of any Maine lake surveyed at the time. Later, in 2004, salmon growth rebounded (see photo above), but that same year a large wild togue population developed,  likely set back any progress made in the salmon fishery for several years.

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Eagle Lake salmon from 2013 showing heavy infestation of larval granulomas of the tapeworm Diphyllobothrium and also adult Eubothrium worms on the far right of photo.

Parasitic Tapeworms

Another major issue facing Eagle Lake salmon is the heavy infestation of two species of tapeworm. These parasites cause severe scarring throughout internal organs, which impacts the fish’s ability to feed and fill their stomach. There are two species of tapeworm we are seeing in salmon at Eagle Lake: Diphyllobothrium and Eubothrium, both of which could be severely impacting salmon growth.  The Diphyll tapeworm can be see in salmon and trout stomachs as larval granulomas – yellow/white nodules throughout the internal organs (see photo). This tapeworm does not develop into a full adult worm until it reaches the gut of a herring gull. Intermediate hosts include not only salmonid fish but also copepods, the zooplankton food commonly consumed by smelt.  The Eubothrium tapeworm matures as an adult within the gut of salmon and can be seen in the far right of the picture as long, thin yellow worms.

Moving Forward

Many factors have contributed to less than ideal salmon fishing at Eagle Lake.  A large number of small, slim salmon is not producing the fishery that many of our anglers would like to see.  While we work to learn more about fish populations in Eagle Lake and improve things where possible, you can help improve salmon growth by keeping your legal limit of small salmon.

 

Smelt Dipping Opportunities West of Ashland

smeltdipping_FRC_70sIce-outs and smelt runs are the talk of angling circles around the state this time of year, and northern Maine is no exception.  Smelts complete their annual spawning run during the nighttime hours in lake tributaries just after the ice leaves.  Where legal, anglers can use dip nets to scoop up a few meals of the silvery fish in a short period of time.

Most Maine waters that have a sport fishery for landlocked salmon are closed to smelt dipping.  Smelts are offered this protection because they are a critical forage fish for salmon, meaning salmon require a steady diet of smelts to grow to be the large-sized fish that anglers want to catch.

smeltsWhile most lakes and tributaries in the Fish River Chain are closed to smelt dipping, folks might not realize that traveling a little farther south and west can open up a lot of opportunity to dip for smelts.  A couple hour drive, bushwhacking through the dark woods, and sloshing through freezing cold water in the pitch black with dip net in hand may not be for everyone, but it can sure make for a fun adventure!

Below are a few waters that have smelt runs and are open to dipping.  They aren’t the only ones out there, though.  Remember that smelts run at night, shortly after ice out in relatively large tributaries to these waters.  Not all have good smelt runs, so you’ll want to investigate and try different areas.  Also be sure to consult the lawbook regarding overall smelt dipping rules as well as regulations specific to a particular water body.

If you decide to venture out west in search of smelts, a good flashlight and GPS unit can be life savers.  Be safe and good luck!

  • Machias Lakes (Big and Little)
  • Clayton Lake (T12 R8)
  • Rowe Lake (T11 R8)
  • Pratt Lake (T11 R9)
  • Upper McNally Pond (T11 R10)
  • Musquacook Lakes (First,Second,Third)
  • Spider Lake (T9 R11)
  • Clear Lake (T10 R11)
  • Island Pond (T10 R10)