Androscoggin River Fish Health Survey

(New Hampshire to Rumford Falls)

by

G. Russell Danner MS, DVM

Maine Department of Inland Fisheries & Wildlife

Matthew Young

University of Maine-Orono

May 23, 2000 – November 20, 2000

 

Summary


Eleven groups of 30 sentinel splake Salvelinus hybrid and one group of 30 rainbow trout Oncorhynchus mykiss were placed in live cages in the Androscoggin River between Gilead, ME and Rumford, ME in an attempt to identify the presence of Infectious Pancreatic Necrosis virus (IPNV) in the river system. The sentinel fish were taken from fish lots previously testing negative for IPNV and other salmonid diseases of regulatory concern and exposed to feral fish and waters of the Androscoggin River for a period of two weeks. After two weeks, the fish were removed from the cages, necropsied, and tested for IPNV and other salmonid diseases. No IPNV or other salmonid pathogen was recovered from the sentinel fish. No IPNV was found in feral fish collected during the project. If IPNV is infecting feral fish in the Androscoggin River between Gilead, ME and Bethel, ME, it is prevalent at a level below the detectible limit of this sentinel fish technique.

This study also supports the findings of Boucher (1997), indicating that late summer water temperatures may be too warm for brook trout. Three groups of sentinel splake perished during the study. Temperature and dissolved oxygen levels indicated that the riverine habitat had become unsuitable for Brook trout.

Introduction


Prior to about 1980, the Androscoggin River below Berlin, NH was known as one of the most polluted waters in North America. Decades of unrestricted discharge of industrial and domestic wastes destroyed habitat for most species of fish and rendered the river unsuitable for most forms of recreation. Since the implementation of the Clean Water Act in 1977, and construction of wastewater treatment facilities, water quality has improved dramatically. With improved biological and aesthetic conditions, the opportunity to develop significant sport fisheries in the Androscoggin River has increased. Several species of warmwater fish, including smallmouth bass Micropterus dolomieui, largemouth bass M. salmoides, and chain pickerel Esox niger have re-established themselves and now support an outstanding fishery in the lower reaches of the river. In recent years, experimental stockings of brown trout Salmo trutta have been made in several areas below Livermore Falls and Lewiston in an effort to establish cold-water fisheries. Brook trout and brown trout were stocked in the upper reaches (Gilead to Jay) from 1986 to 1990. Stocking in this area was terminated because creel survey data showed very low angler use. Low angler interest was attributed to the continued perception of the river as being highly polluted, and the issuance of a fish consumption advisory on the Androscoggin River in 1987 (Boucher 1997).

In 1985, the Maine Department of Inland Fisheries and Wildlife conducted a survey of fisheries habitat on 35.7 miles of the Androscoggin River from the Maine-New Hampshire border in Gilead to Rumford Falls. More recently, MDIFW staff conducted electro fishing surveys on this reach of the main river and on several tributaries, and staff from the Maine Department of Environmental Protection collected basic water quality information and sampled predator fish from several sites in the main river.

In 1999, the New Hampshire Department of Fish and Game’s Warren Fish Hatchery experienced an epidemic of Infectious Pancreatic Necrosis virus (IPNV). The viral pathogen became very virulent and killed both young fish and adult broodstock brook trout. The Warren Fish Hatchery stocks fish into the Upper Androscoggin River. The New Hampshire Fish and Game Department is currently implementing improvements in fish health management in an effort to contain and remove the pathogen from their hatchery. How this pathogen may be affecting salmonids in the Androscoggin River has not been established. No reports of fish deaths have occurred. However, this affords an excellent opportunity to survey the upper Androscoggin River from New Hampshire to Rumford Falls for IPNV and other fish pathogens since we know that the pathogen has recently occurred within the watershed.

Between May and September 2000, traps containing 30- (120-180 mm) splake were placed in the river for 14 days. These sentinel fish were retrieved from the river, euthanized, examined, necropsied, and tested for salmonid pathogens of regulatory concern. Sentinel fish were placed in locations corresponding to locations previously surveyed by MDIFW for salmonid habitat and DEP for water quality as reported by D. Boucher (1997).

Objectives

1. Assess the presence of Infectious Pancreatic Necrosis virus being shed from infected fish originating at the Warren, New Hampshire fish hatchery into the upper Androscoggin River watershed.
2. Assess the usefulness of sentinel fish for screening wild fish populations for certain fish pathogens.
3. Assess effectiveness of a 14-day exposure of sentinel fish to a wild fish population.


Methods


Study Area Description

The Androscoggin River originates in Erroll, NH at the outlet of Umbagag Lake and flows 161 miles before emptying into Merrymeeting Bay at Brunswick, Maine. The drainage area of the Androscoggin River above the Maine-New Hampshire border is 1,502 square miles (See Figure 1). Flows are regulated by a series of storage and hydroelectric dams on the major headwater lakes, which include Kennebago, Rangeley, Mooselookmeguntic, Upper Richardson and Lower Richardson, Aziscohos, and Umbagog. Minimum flows are generally maintained in excess of 1,600 cubic feet per second (cfs) at Rumford; average annual daily flow at Rumford is approximately 3,700 cfs. Gradient in the reach between New Hampshire and Rumford Falls averages 3.9 feet per mile. The Androscoggin River from New Hampshire to Rumford Falls contains about 1,800 acres of habitat with an average depth of 5 feet. About 50% is pool habitat that average 11 feet deep. The river from New Hampshire to Bethel is primarily shallow riffles and runs over gravel, sand, and rubble substrate. Below Bethel, the river broadens and deepens and the predominant substrate is sand. Temperature and dissolved oxygen values are suitable for salmonid management on a year-round basis.

Many of the headwater lakes and rivers, which include Rangeley Lake, and Kennebago River, support fisheries for brook trout and landlocked salmon that are of statewide significance. Brook trout, rainbow trout, brown trout, and landlocked salmon, from both wild and hatchery stocks, provide the principal fisheries in the main river between Umbagog Lake and the New Hampshire border. Wild and stocked populations of rainbow trout, brown trout, and brook trout provide a limited fishery from Gilead to Rumford Falls.

Major tributary streams in the reach between Gilead and Rumford Falls include the Wild River, Pleasant River, Sunday River, Bear River, Ellis River, and Concord River. There are no barriers to fish movement in the main river between Gilead and Rumford Falls (henceforth referred to as the upper Androscoggin River).

Boat access to the upper Androscoggin River is available at two sites, the Virginia Impoundment in West Bethel, and at Gilead. MDIFW will be developing a site at Rumford Center. The upper Androscoggin River is open to fishing from April 1 to September 30 with the following restrictions: daily bag limit on trout (includes brook trout, brown trout, and rainbow trout): 2 fish; daily bag limit on salmon: 2 fish; minimum length limit on salmon, brown trout, and rainbow trout: 12 inches; minimum length limit on brook trout: 6 in; daily bag on bass: 1 fish between 12 and 15 inches; artificial lures only for bass. The river is open to catch and release fishing for trout, salmon, bass from October 1 to November 30.

Sentinel Fish

Three hundred thirty splake from certified disease-free stocks at the Governor Hill State Fish Hatchery were used for this survey. Fish lot number F1300769837. Thirty rainbow trout from the Dry Mills State Fish Hatchery were used for this survey. Fish lot number F0150649922.

Feral fish were angled during the study. These fish were tested separately.

Thirty fish were placed in a ½-inch plastic wire mesh tubular minnow trap (15 in diameter x 48 in long) at the test site and secured to the riverbed with a rope and anchor. The test site was marked with appropriate Department information. Fish were not fed during the test period. Fish were checked at least once per week. Fish were placed in a site remote from heavy human traffic and completely submerged. Only two fish traps were put into the water at any time.

Necropsy Procedures

Fish were euthanized and tested according to procedures outlined in American Fisheries Society Blue Book. Suggested Procedures for the Detection and Identification of Certain Finfish and Shellfish Pathogens. Fourth Edition 1994. A Maine Fish Health Laboratory necropsy report was completed for sentinel fish and wild fish from each test site (see attached forms).

Results


Objectives

1. Assess the presence of Infectious Pancreatic Necrosis virus being shed from infected fish originating at the Warren, New Hampshire fish hatchery into the upper Androscoggin River watershed.
2. Assess the usefulness of sentinel fish for screening wild fish populations for certain fish pathogens.
3. Assess effectiveness of a 14-day exposure of sentinel fish to a wild fish population.


Objective 1 Results

The study was conducted for 12 weeks. Thirty sentinel splake were place in cages each of 11 weeks; and 30 rainbow trout were placed in a cage the final week. No sentinel fish were detected with IPNV or any salmonid pathogen of regulatory concern. No feral fish were detected with IPNV. If IPNV is affecting the salmonid population in the Androscoggin River between Gilead and Bethel, the level of virus is below the detectible level of this study procedure.

Objective 2 Results

No fish pathogens were found on any sentinel fish.

Objective 3 Results

It is not possible to assess the effectiveness of this sentinel fish procedure, because no IPNV positive fish were recovered. However, the mechanics of the study were very successful. The cages worked well, only one cage was lost or stolen. No cages failed and no fish escaped from the cages. In order to evaluate the validity of the procedure, an endemic IPNV population may need to be used.

Other Results

Smallmouth bass were found with Bass tapeworm Proteocephalus ambloplitis infestations. Fallfish were found with metacercariae infestations on internal organs. No other significant findings were noted. The river temperature became too warm to support splake and three groups died before they could be tested.

Necropsy Reports from each site follow.

Reference


Boucher, D.P. 1997 Androscoggin River Survey (New Hampshire to Rumford Falls) Maine Department of Inland Fisheries & Wildlife, Augusta.

Necropsy Report

For:

Site A: Whites Brook

Androscoggin River Fish Health Survey

Date: 6/2/00 - 6/16/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Androscoggin River, Maine  

Fish Species:
- Smallmouth bass Micropterus dolomieui 2
- Fallfish Semotilus corporalis 5 week 1; 1 week 2 Sentinel Fish in Trap: 30 Splake
Number:
- 38
Size:
- mixed
Body surface:
- no gross abnormalities seen.
Fins:
- no gross abnormalities seen.
Liver:
- fallfish have small white nodules on many internal organs. Appear to be metacercaria of Tremotodes.
Spleen:
- fallfish have small white nodules on many internal organs. Appear to be metacercaria of Tremotodes.
Posterior Kidney:
- no gross abnormalities seen.
Dermal Lesions:
- no gross abnormalities seen.
Eyes:
- no gross abnormalities seen.
Body cavity:
- SMB have internal scarring consistent with Bass Tapeworm infectiom
Gall bladder:
- no gross abnormalities seen.
Adipose tissue:
- no gross abnormalities seen.
Gonads:
- no gross abnormalities seen.
Stomach:
- no gross abnormalities seen.
Gastrointestinal Tract:
- Adult bass tapeworms found in intestines of SMB
Gas bladder:
- no gross abnormalities seen.
Musculature:
- no gross abnormalities seen.
Brain:
- not examined
Other:
- none

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other A. sobria in fall fish Pos

 

Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic Necrosis virus Cell culture Neg
Viral Hemorrhagic Septicemia virus Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Result
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Pos
Other    
Trematode in fallfish Species not keyed out Pos

 

Treatment: None

Outcome: None

Sequella: None

Necropsy performed by: G. Russell Danner MS, DVM

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Necropsy Report

For: Site B: Little Larry Brook Androscoggin River Fish Health Survey Date: 6/9/00 - 6/23/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Little Larry Brook, Maine  

Fish Species:
- No wild fish caught.
Sentinel Fish in Trap: 30 Splake
Number:
- 30
Size:
- fingerlings (approximately 4-6 inches)
Body surface:
- No gross abnormalities seen.
Fins:
- No gross abnormalities seen.
Liver:
- No gross abnormalities seen.
Spleen:
- No gross abnormalities seen.
Posterior Kidney:
- No gross abnormalities seen.
Dermal Lesions:
- No gross abnormalities seen.
Eyes:
- No gross abnormalities seen.
Body cavity:
- No gross abnormalities seen.
Gall bladder:
- No gross abnormalities seen.
Adipose tissue:
- No gross abnormalities seen.
Gonads:
- No gross abnormalities seen.
Stomach:
- No gross abnormalities seen.
Gastrointestinal tract:
- No gross abnormalities seen.
Gas bladder:
- No gross abnormalities seen.
Musculature:
- No gross abnormalities seen.
Brain:
- Not examined
Other
- None

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other:    
     
Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic necrosis virus Cell culture Neg
Viral Hemorrhagic Septicemia virus Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Result
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Neg
Other   N/A

 

Treatment:

Outcome:

Sequella:

Necropsy performed by:

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Necropsy Report

For: Site C: Chapman Brook
Androscoggin River Fish health Survey
Date: 6/23/00 - 7/7/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Chapman Brook, Maine  

 

Fish Species:
- Sentinel Fish in Trap: 3- Splake
Number:
- 30
Size:
- fingerlings (approximately 4-6 inches)
Body surface:
- No gross abnormalities seen.
Fins:
- No gross abnormalities seen.
Liver:
- No gross abnormalities seen.
Spleen:
- No gross abnormalities seen.
Posterior Kidney:
- No gross abnormalities seen.
Dermal Lesions:
- No gross abnormalities seen.
Eyes:
- No gross abnormalities seen.
Body cavity:
- No gross abnormalities seen.
Gall bladder:
- No gross abnormalities seen.
Adipose tissue:
- No gross abnormalities seen.
Gonads:
- No gross abnormalities seen.
Stomach:
- No gross abnormalities seen.
Gastrointestinal tract:
- No gross abnormalities seen.
Gas bladder:
- No gross abnormalities seen.
Masculature:
- No gross abnormalities seen.
Brain:
- Not examined
Other
- None

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease Renibacterium Salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other:    
     
Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic Necrosis virus Cell culture Neg
Viral Hemorrhagic
Septicemia virus
Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Results
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Neg
Other   N/A

 

Treatment:

Outcome:

Sequella:

Necropsy performed by:

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Necropsy Report

For: Site D: Androscoggin River Near Whites Brook
Androscoggin River Fish health Survey
Date: 6/30/00 - 7/14/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Androscoggin River, Maine  

 

Fish Species:
- No wild fish caught.
Sentinel Fish in Trap: 30 Splake
Number:
- 30
Size:
- fingerlings (approximately 4-6 inches)
Body surface:
- No gross abnormalities seen.
Fins:
- No gross abnormalities seen.
Liver:
- No gross abnormalities seen.
Spleen:
- No gross abnormalities seen.
Posterior Kidney:
- No gross abnormalities seen.
Dermal Lesions:
- No gross abnormalities seen.
Eyes:
- No gross abnormalities seen.
Body cavity:
- No gross abnormalities seen.
Gall bladder:
- No gross abnormalities seen.
Adipose tissue:
- No gross abnormalities seen.
Gonads:
- No gross abnormalities seen.
Stomach:
- No gross abnormalities seen.
Gastrointestinal tract:
- No gross abnormalities seen.
Gas bladder:
- No gross abnormalities seen.
Masculature:
- No gross abnormalities seen.
Brain:
- Not examined
Other
- None

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease Renibacterium Salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other:    
     
Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic Necrosis virus Cell culture Neg
Viral Hemorrhagic
Septicemia virus
Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Results
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Neg
Other   N/A

 

Treatment:

Outcome:

Sequella:

Necropsy performed by:

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Necropsy Report

For: Site E: Bog Brook
Androscoggin River Fish health Survey
Date: 7/7/00 - 7/14/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Bog Brook, Maine Accidentally put in bog brook instead of Wheeler because Wheeler was dry at this time.  

 

Fish Species:
- No wild fish caught.
Sentinel Fish in Trap: 30 Splake
Number:
- 30
Size:
- fingerlings (approximately 4-6 inches)
Body surface:
- No gross abnormalities seen.
Fins:
- No gross abnormalities seen.
Liver:
- No gross abnormalities seen.
Spleen:
- No gross abnormalities seen.
Posterior Kidney:
- No gross abnormalities seen.
Dermal Lesions:
- No gross abnormalities seen.
Eyes:
- No gross abnormalities seen.
Body cavity:
- No gross abnormalities seen.
Gall bladder:
- No gross abnormalities seen.
Adipose tissue:
- No gross abnormalities seen.
Gonads:
- No gross abnormalities seen.
Stomach:
- No gross abnormalities seen.
Gastrointestinal tract:
- No gross abnormalities seen.
Gas bladder:
- No gross abnormalities seen.
Masculature:
- No gross abnormalities seen.
Brain:
- Not examined
Other
- None

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease Renibacterium Salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other:    
     
Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic Necrosis virus Cell culture Neg
Viral Hemorrhagic
Septicemia virus
Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Results
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Neg
Other   N/A

 

Treatment:

Outcome:

Sequella:

Necropsy performed by:

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Necropsy Report

For: Site F: Sunday River
Androscoggin River Fish health Survey
Date: 6/9/00 - 6/23/00
Cc: Peter Bourque, Maine IF&W, Augusta, ME.  
RE: Androscoggin River Fish Health Survey  
  Water: Sunday River, Maine  

 

Fish Species:
- Brook trout Salmo trutta one.
Sentinel Fish in Trap: 30 Splake
Number:
- 30
Size:
- fingerlings (approximately 4-6 inches)
Body surface:
- No gross abnormalities seen.
Fins:
- No gross abnormalities seen.
Liver:
- No gross abnormalities seen.
Spleen:
- No gross abnormalities seen.
Posterior Kidney:
- No gross abnormalities seen.
Dermal Lesions:
- No gross abnormalities seen.
Eyes:
- No gross abnormalities seen.
Body cavity:
- No gross abnormalities seen.
Gall bladder:
- No gross abnormalities seen.
Adipose tissue:
- No gross abnormalities seen.
Gonads:
- No gross abnormalities seen.
Stomach:
- No gross abnormalities seen.
Gastrointestinal tract:
- No gross abnormalities seen.
Gas bladder:
- No gross abnormalities seen.
Masculature:
- No gross abnormalities seen.
Brain:
- Not examined
Other
- None

 

Bacteriology Detection Method Results
Furunculosis (Aeromonas salmonicida) TSA & serology Neg
Enteric Red Mouth Disease (Yersinia ruckerii) TSA & serology Neg
Bacterial Kidney Disease Renibacterium Salmoninarum) direct fluorescent antibody test Neg
Bacterial Kidney Disease (Renibacterium salmoninarum) Selective media culture N/A
Other:    
     
Virology Detection Method Results
Infectious Pancreatic Necrosis virus Cell culture Neg
Infectious Hematopoetic Necrosis virus Cell culture Neg
Viral Hemorrhagic
Septicemia virus
Cell culture Neg
Oncorhynchus Masou virus Cell culture Neg
Infectious Salmon Anemia virus Cell culture Neg
Other    
     
Parasites: Detection Method Results
Whirling Disease Myxobolus cerebralis Plankton centrifuge method N/A
Ceratomyxosis (Ceratomyxa shasta)   N/A
Gill Louse (Salmonicola edwardsi)   Neg
Bass Tapeworm (Proteocephalus ambloplitis)   Neg
Other   N/A

 

Treatment:

Outcome:

Sequella:

Necropsy performed by:

Maine Department of Inland Fisheries & Wildlife

RR 5 Box 975 Burns Road

Augusta, ME 04330

(207) 287-2813 phone/fax

Week 8: All fish in trap died at location above Rumford Point. Water temperature and Dissolved Oxygen levels were measured. The water was probably too warm and fish were in unshaded sunlight. Fish were fine at inspection after one week.

Week 10: All fish in trap died at location in Androscoggin River near Bethel in Twitchel Brook. Water temperature and Dissolved Oxygen levels were measured. The water was probably too warm. Fish were fine at inspection after one week.

Week 11: All fish in trap died at a location below bridge on Androscoggin River. Fish were fine at inspection after one week. A 30 wild fish, small brook trout and rainbow trout colleted by electro fishing small streams with the assistance of Region D Fisheries Biologist, Dave Boucher; was negative for all salmonid pathogens of regulatory concern.

Week 12: Trap anchor was cut. Trap and fish were gone. This was the only trap that was tampered with during the 12 weeks the study was conducted. It is possible anchoring line fatigued and broke in the strain of the current at this location.