U.S. Department of the Interior

U.S. Geological Survey

USGS Scientific Investigations Report 2006-5214 

NOAA Technical Memorandum NOS NCCOS 41

USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, 

May 7-10, 2006, Annapolis, Maryland

U.S. Department of Commerce

National Oceanic and Atmospheric Administration

National Ocean Service
A. U.S. Fish and Wildlife Service biologist weighing Chesapeake Bay striped bass exhibiting skin lesions. Photo by 

Christine L. Densmore, U.S. Geological Survey

B. Stained tissue section taken from the spleen of a Chesapeake Bay striped bass exhibiting granulomatous lesions 

associated with a mycobacterial infection. Photo by David Gauthier, Virginia Institute of Marine Science

C. Chesapeake Bay striped bass exhibiting emaciation and skin lesions consistent with mycobacteriosis. Photo by 

Mark Matsche, Maryland Department of Natural Resources

D. Collection of blood sample from striped bass harvested from the Nanticoke River, Maryland, in November 2002. 

Photo by Mark Matsche, Maryland Department of Natural Resources

E. U.S. Geological Survey field crew processing striped bass as part of a mycobacteriosis survey conducted in the 

tidal portions of Chesapeake Bay rivers during 2002 and 2003. Photo by Mark Matsche, Maryland Department of Natural 

Resources

F. Live well transport and landing of striped bass by U.S. Fish and Wildlife personnel. Photo by Mark Matsche, 

Maryland Department of Natural Resources

A.

B.

C.

D.

E. F.
USGS/NOAA Workshop on 

Mycobacteriosis in Striped Bass, 

May 7-10, 2006, Annapolis, Maryland

Edited By Christopher A. Ottinger and John M. Jacobs

USGS Scientific Investigations Report 2006–5214 

NOAA Technical Memorandum NOS NCCOS 41

U.S. Department of the Interior

U.S. Geological Survey

U.S.Department of Commerce

National Oceanic and Atmospheric Administration

National Ocean Service
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Deptartment of Commerce

CARLOS M. GUTIERREZ, Secretary

National Oceanic and Atmospheric Administration

Conrad C. Lautenbacher, Jr., Administrator

National Ocean Service

John (Jack) H. Dunnigan, Assistant Administrator

U.S. Geological Survey, Reston, Virginia: 2006

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Suggested citation:

Ottinger, C.A., and Jacobs, J.M., 2006, USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7-10, 2006, 

Annapolis, Maryland: U.S. Geological Survey Scientific Investigations Report 2006-5214 / National Oceanic and 

Atmospheric Administration Technical Memorandum NOS NCCOS 41, 42 p.
iii

Contents

Executive Summary.......................................................................................................................................1

Workshop Organization ................................................................................................................................2

Objectives...............................................................................................................................................2

Technical Review Panel.......................................................................................................................3

Workshop Outcomes.....................................................................................................................................3

State of Knowledge ..............................................................................................................................3

Scientific Abstracts..............................................................................................................................5

A historical perspective on diseases of striped bass with emphasis on 

mycobacteriosis. ............................................................................................................6

The ecology of mycobacteria infecting striped bass (Morone saxatilis) in 

Chesapeake Bay: A research plan..............................................................................7

Striped bass mycobacteriosis: A zoonotic disease of concern in Chesapeake Bay. ......9

Striped bass disease overview for the past ten years plus................................................10

Survey of gametes and juvenile striped bass (Morone saxatilis) for 

mycobacteriosis from the Chesapeake Bay: Sampling methods, 

external lesions, and histopathology. .......................................................................12

Microbiology of gametes and age 0-3 striped bass (Morone saxatilis). ..........................13

Mycobacterial infections in striped bass (Morone saxatilis) from upper and 

lower Chesapeake Bay: 2002 and 2003 pound net studies....................................15

Epizootiology of mycobacteriosis in Chesapeake Bay striped bass 

(Morone saxatilis): Large-scale field survey. ..........................................................16

Mycobacteriosis in juvenile Atlantic menhaden..................................................................17

The influence of dietary intake on the progression and severity of 

mycobacteriosis in striped bass (Morone saxatilis). .............................................19

Mycobacteriosis in Chesapeake Bay fishes: Perspectives and questions. ....................20

Initial investigation of the overall health and presence of mycobacteriosis 

in Roanoke River, NC, striped bass (Morone saxatilis)..........................................22

Mycobacterial infections in striped bass (Morone saxatilis) from Delaware Bay. ........23

Tag-recapture data from Chesapeake Bay striped bass indicate that 

natural mortality has increased.................................................................................25

Epizootic mycobacteriosis in Chesapeake Bay striped bass: What is the fate 

of infected fish? ............................................................................................................26

Perspective of Resource Managers.........................................................................................................28

Prioritized Research Needs .......................................................................................................................31

Research Integration and Role of Federal Agencies.............................................................................33

Appendix 1: Workshop Agenda. ................................................................................................................35

Appendix 2: Prioritized Research Agenda with Estimated Timelines for Completion. .....................37

Appendix 3: Participant List........................................................................................................................38
iv
USGS/NOAA Workshop on Mycobacteriosis in Striped Bass,

May 7 – 10, 2006, Annapolis, Maryland

By C. A. Ottinger and J.M. Jacobs

Executive Summary

As a Federal trust species, the well-being of the striped 

bass (Morone saxatilis) population along the Eastern Seaboard 

is of major concern to resource users. Striped bass are an 

extremely valuable commercial and recreational resource. As 

a principal piscivore in Chesapeake Bay, striped bass directly 

or indirectly interact with multiple trophic levels within the 

ecosystem and are therefore very sensitive to biotic and abiotic 

ecosystem changes. For reasons that have yet to be defined, 

the species has a high intrinsic susceptibility to mycobacteriosis. This disease has been impacting Chesapeake Bay striped 

bass since at least the 1980s as indicated by archived tissue 

samples. However, it was not until heightened incidences of 

fish with skin lesions in the Pocomoke River and other tributaries of the Chesapeake Bay were reported in the summer and 

fall of 1996 and 1997 that a great deal of public and scientific 

interest was stimulated about concerns for fish disease in the 

Bay.

By 2005, multiple research groups had studied or were 

independently investigating this disease issue. Identified 

research redundancies made apparent the need for improved 

communications, integration of science efforts, and resource 

optimization. In May of 2006, the U.S. Geological Survey 

(USGS), Leetown Science Center, partnered with the National 

Oceanographic and Atmospheric Administration/ National 

Ocean Service (NOAA/NOS), Cooperative Oxford Laboratory, to sponsor a workshop on mycobacteriosis in Chesapeake Bay striped bass. This workshop involved the principal 

Federal, State, and academic scientists involved with this issue 

as well as the resource managers. The goals of this workshop 

were to:

Establish the state of knowledge;

Develop a prioritized research agenda; and

Identify mechanisms by which research efforts could be 

optimized.

The workshop structure included oral presentations with 

associated extended abstracts, formal group discussions, and 

1.

2.

3.

a panel discussion that involved resource managers from 

NOAA’s National Marine Fisheries Service, the Maryland 

Department of Natural Resources, and the Virginia Marine 

Resources Commission. The workshop also included a 

review panel charged with assessing information generated 

in the workshop and providing input on state of knowledge, 

knowledge gaps, and information needs pertaining to mycobacteriosis in Chesapeake Bay striped bass. The review panel 

was composed of scientists from USGS, NOAA, Food and 

Drug Administration (FDA), U.S. Fish and Wildlife Sevice 

(USFWS), and Cornell University. Additional information and 

guidance was provided by the former head of the Tuberculosis/Mycobacteria group at the Centers for Disease Control and 

Prevention (CDC), Atlanta. The initial release of outcomes 

was made by way of a press conference held at the end of 

the workshop. The press conference featured a brief formal 

presentation followed by formal and informal question and 

answer sessions. Press conference attendees included reporters 

from the major regional newspapers (Baltimore Sun, Washington Post, etc.), the Associated Press, and a local television 

station.

A substantial portion of the research presented at the 

workshop resulted from projects that had been completed 

within the last year or from projects that were in progress. 

These new data created some additional challenges for the 

review panel. However, the willingness of workshop participants to provide the data made an up-to-date state of knowledge statement possible. Synthesis of multiple data sets that 

occurred as part of the workshop process made apparent trends 

that had been either partially recognized or not seen at all.

Mycobacteria-associated infection and disease in Chesapeake Bay striped bass is age and sex dependent. The relative 

prevalence and severity of the disease has both spatial and 

temporal components. Temporal components appear to be 

relatively stable, with the most severe disease occurring during the late summer and fall. Spatial components appear less 

stable, with the exception of potential foci located in the northern region of the Bay. Modes of disease transmission remain 

poorly described. Limited data indicate that infections can be 

transmitted via the water column. Additional data indicate the 
occurrence of mycobacteria associated with gametes, suggesting the possibility of adults transferring the infection to their 

progeny, a process known as vertical transmission. Multiple 

species of teleosts within Chesapeake Bay have been found to 

be infected with mycobacteria, suggesting the possibility of 

trophic transfers of infection.

Trophic interactions may also be affecting striped bass 

nutrition. Concurrent with an increase in skin lesions in the 

late 1990s was an elevated frequency of emaciated striped 

bass. Inadequate nutrition has been shown to increase severity 

and progression of mycobacteriosis in striped bass. However, 

mycobacteriosis is commonly associated with reductions in 

fitness. The question of whether Chesapeake Bay striped bass 

are skinny because of mycobacteriosis or whether poorly 

nourished and therefore skinny bass are developing the disease 

has yet to be answered. Data collected to date suggest that a 

combination of both scenarios may be occurring. Although 

there was some disagreement regarding modeling methods 

employed by the Atlantic States Marine Fisheries Commission 

(ASMFC) for stock assessment, population data generated 

through tagging programs in Chesapeake Bay seem to indicate 

that the natural mortality rate in the spawning component of 

the striped bass stock had increased dramatically (2x to 3x) 

beginning in the late 1990s. The most recent tag return data 

indicate that natural mortality rates in the southern region 

of the Bay have returned to historic norms. The rate in the 

northern region of the Bay remains high. The relationship, if 

any, between this apparent increase in natural mortality and 

the mycobacteriosis epizootic has yet to be established. However, the simultaneous occurrence of the two events has raised 

concerns about the potential impact of mycobacteriosis on the 

striped bass population. Corresponding declines in spawning 

stock biomass and recruitment have not been noted.

 Determining the impact of mycobacteriosis on striped 

bass populations throughout the Chesapeake Bay watershed 

was the top priority of both resource managers and participating scientists. Other priorities included developing a 

better understanding of mycobacterial ecology, especially 

as it relates to disease transmission, and the characterization 

of stressors that increase striped bass disease susceptibility. The development of the prioritized research agenda was 

supplemented by the identification of several overarching 

themes. Workshop participants recognized that the scope of 

this disease issue transcends individual research or resource 

management organizations and that its resolution will require 

integration of effort and optimization of available resources. 

The need to consider socioeconomic and human health concerns was also recognized. Final recommendations from the 

workshop included the development of a multiagency steering 

committee that will be charged with issues including:

The continued development of diagnostic tools and methods standardization;

Development of a standardized data base for all data 

related to mycobacteriosis/striped bass research in Chesapeake Bay as well as adjacent estuaries;

1.

2.

Transfer of data for use in ecosystem modeling such as 

the program currently being developed by the NOAA 

Chesapeake Bay Program; and

The development of a communications network designed 

to rapidly disseminate research findings, announce 

upcoming research activities, and provide guidance on 

research needs as the knowledge base evolves.

While mycobacteriosis in Chesapeake Bay striped bass 

was once viewed as a single resource issue, the complexity 

that is only beginning to be appreciated is forcing a broader 

view in the context of ecosystem health and ecosystem 

change. Striped bass populations have historically been managed in isolation. New fishery management models include 

multiple stocks in recognition of the ecological relatedness of 

individual species. Fishery managers once viewed disease as 

an unexplainable component of natural mortality in population 

models. This perspective is slowly changing. Now, integrated 

fisheries management requires the consideration of interactions (biotic and abiotic) and thus dramatically increases 

information needs and, by extension, provides data about the 

ecosystem that has broader application. This information need 

can best be met through highly integrated and well-coordinated research programs. The development of such a program 

will be the ultimate indicator of the success of the USGS/

NOAA Workshop on Mycobacteriosis in Striped Bass.

Workshop Organization

Objectives

The overarching goal of this workshop was to provide a 

synthesis of current understanding regarding mycobacteriosis 

and its ecological effects, and to provide recommendations 

that will facilitate a coordinated approach by funding agencies 

and researchers in their collective efforts to effectively and 

efficiently address this research topic.

Specific objectives of this workshop were to:

Characterize the state of knowledge regarding mycobacteriosis in Chesapeake Bay striped bass;

Assess striped bass – mycobacteriosis relationships 

throughout Chesapeake Bay and place them into a geographic perspective relative to the conditions in other East 

Coast coastal systems;

Identify and describe ongoing research projects relevant 

to the disease;

Provide a consensus-derived prioritized research approach 

for the short term (1-2 years) and long term (3-5 years) 

that will yield a better understanding and improved 

3.

4.

1.

2.

3.

4.

   USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
management advice pertaining to mycobacteriosis issues 

pertinent to Chesapeake Bay ecosystem-based management and restoration;

Identify strategies for the implementation of research 

plans; and

Produce a workshop technical report and non-technical 

informational products for use by the larger research and 

resource management communities, lawmakers, and the 

general public.

Technical Review Panel

Based on the submitted research summaries, presentations, and existing peer-reviewed literature, the review panel 

was charged with making determinations on the state of 

knowledge in areas related to pathogenesis, transmission, 

distribution, pathogen characterization, pathogen-host interactions, disease ecology, and host population effects. The 

panel was also asked to make recommendations on research 

prioritization using input from workshop breakout sessions. 

The review panel was composed of the following scientists 

with knowledge of and familiarity with the issue and the Bay 

(Table 1).

5.

6.

Table 1. Mycobacteriosis in Striped Bass Technical Review 

Panel

Name Affiliation

Dr. Vicki Blazer 

(Panel Chair)

US Geological Survey

Leetown Science Center

Kearneysville, WV

Dr. Kay Briggs US Geological Survey

Biological Resources 

Discipline

Reston, VA

Mr. John Coll US Fish and Wildlife Service

Northeast Fisheries Center

Lamar, PA

Dr. Andrew Draxler NOAA/National Ocean Service

Ecosystem Processes Division

Highlands, NJ

Dr. Rod Getchell Cornell University

Veterinary Medical Center

Ithaca, NY

Dr. Renate Reimschuessel Food and Drug Administration

Center of Veterinary Medicine

Laurel, MD

Dr. Carl Sindermann 

(retired)

NOAA/National Ocean Service

Oxford Marine Laboratory

Oxford, MD

Workshop Outcomes

State of Knowledge

Presented by Vicki Blazer, Research Fishery Biologist 

U.S. Geological Survey, Leetown Science Center 

(representing the findings of the Technical Review 

Panel)

Mycobacteriosis in Chesapeake Bay striped bass (Morone 

saxatilis) is characterized by cutaneous lesions, viscerallesions, or a combination of the two. These lesions are typified 

by a granulomatous inflammatory response to the mycobacteria that act as an intracellular pathogen in macrophages. 

Spleen and kidney are the primary target organs in Chesapeake 

Bay striped bass, but the disease can be systemic. Mycobacteriosis is a chronic disease that develops slowly. Pathogenesis 

is dependent on the Mycobacterium sp. involved, may be dose 

dependent, and is temperature dependent. Striped bass can be 

infected with mycobacteria without exhibiting pathology.

Mycobacteriosis has been impacting Chesapeake Bay 

striped bass since at least 1984. The prevalence of this disease 

has increased in the Maryland portion of the Bay since 1998 as 

indicated by data from the Maryland Department of Natural Resources. Prevalence in the main stem of the Bay may 

have stabilized from 2003 to 2005. The characterization of 

mycobacterial infection prevalence is complex and is based 

on age, sex, and life history. The development of disease is 

age dependent. Infections are observed in young-of-the-year 

striped bass. Granulomas containing acid-fast bacilli are 

observed in age 1 fish or older. Disease prevalence increases 

in both male and female fish to age 6. After age 6, prevalence 

appears to decline in females. Male and female Chesapeake 

Bay striped bass exhibit different life histories, with the female 

fish leaving the Bay at a younger age. Infection prevalence of 

over 50% has been reported in 3 to 4 year male striped bass 

collected from commercial pound nets located at the mouths 

of rivers in both Virginia and Maryland. Infection and disease 

prevalence of approximately 80% have been reported for age 6 

male and female fish.

Striped bass with mycobacteriosis have been harvested 

from the tidal portions of multiple rivers flowing into Chesapeake Bay and from the Bay’s main stem. Main-stem samples 

containing diseased fish have come from both the Maryland 

and Virginia portions of the Bay. Rivers from which diseased 

striped bass have been obtained include the James, Rappahannock, and York in Virginia; the Virginia and Maryland portions of the Potomac; and the Chester, Choptank, Nanticoke, 

Pocomoke, and Sassafras in Maryland. Differences in infection and disease prevalence as well as disease severity have 

been observed between sample sites, but site-specific trends 

Workshop Outcomes 
have yet to be established. Some temporal fluctuations in 

disease have been observed. Most notable is the increase in the 

frequency of skin lesions in the fall (September – November) 

relative to spring (March – May) and summer (June – August).

Limited data have been obtained on mycobacteriosis in 

East Coast striped bass outside Chesapeake Bay. In Delaware 

Bay, a spleen-dominated disease presentation was observed 

but prevalence was low (18%). The few mycobacterial isolates 

obtained were not those commonly obtained from Chesapeake 

Bay striped bass. Striped bass from Roanoke River (North 

Carolina) exhibited a spleen-dominated presentation and low 

prevalence (18%). Infection was not confirmed by bacterial 

culture. Mycobacteriosis has been detected in the Atlantic 

Coast migratory stock and Chesapeake Bay spawning stock by 

histopathology; however, low sample size prohibited estimation of prevalence.

Multiple species of Mycobacterium have been isolated 

from Chesapeake Bay striped bass and some infections 

involve more than one Mycobacterium sp. Two new species, 

M. shottsii and M. pseudoshottsii, obtained from Chesapeake 

Bay striped bass have been described and officially recognized. The mycobacteria from the striped bass have different 

growth characteristics in vitro and little is known regarding 

virulence. Fatty acid differences in the cell walls of many of 

the Mycobacterium spp. infecting Chesapeake Bay striped 

bass have been documented and appear to be useful for speciation.

Little is known regarding the transmission of mycobacterial infections in Chesapeake Bay striped bass. Mycobacteria have been cultured from gamete samples obtained from 

spawning striped bass harvested from two rivers in Maryland. As was noted above, young-of-the-year striped bass 

are infected. The association of mycobacteria with gametes 

and young-of-the-year infection indicates the possibility of 

vertical transmission. However, there is no evidence to date 

to demonstrate if young-of-the-year fish are infected during 

development or sometime post hatch. Evidence for oral/food 

transmission has been developed for other teleost species. 

Striped bass prey species, such as Atlantic menhaden, can be 

infected. Limited laboratory data provide some evidence for 

possible aqueous horizontal exposure. Trauma injury resulting from nets, parasites, and catch and release angling or the 

culling of sublegal-length fish from commercial nets cannot be 

dismissed as a possible avenue for infection.

Some data are available on pathogen-host interactions. 

In vitro as well as in vivo studies have been performed to 

document the interactions of striped bass macrophages with 

some of the Mycobacterium spp. infecting striped bass in 

Chesapeake Bay. Additional laboratory studies have demonstrated that the severity and progression of the disease is 

severely impacted by nutritional competency of the fish when 

challenged with one Mycobacterium (M. marinum) infecting 

Chesapeake Bay striped bass.

Very little is known regarding the ecology of mycobacteria infecting fish in the Chesapeake Bay ecosystem. We know 

of no studies in Chesapeake Bay that have attempted to isolate 

these specific pathogens from water or substrate. The various 

mycobacterial isolates from fish do show marked temperature 

preference when grown in vitro.

Nothing is known regarding the impact of mycobacteriosis on striped bass at the population level. The size of the 

estuarine/marine striped bass population in the Atlantic States 

is at a record high. There was significant disagreement regarding natural mortality modeling methods used with population 

data generated through tagging programs administered by the 

ASMFC in Chesapeake Bay. The results of the modeling may 

indicate that the natural mortality rate in the spawning component of the striped bass stock had increased dramatically (2x to 

3x) beginning in the late 1990s with a return to historic norms 

in the lower Bay and a continued elevation in the upper Bay 

by 2005. Any relationship between this potential increase in 

natural mortality and the mycobacteriosis epizootic has yet to 

be established.

 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Scientific Abstracts

A historical perspective on diseases of striped bass with emphasis on mycobacteriosis .....6

The ecology of mycobacteria infecting striped bass (Morone saxatilis) in 

Chesapeake Bay: A research plan.......................................................................................7

Striped bass mycobacteriosis: A zoonotic disease of concern in Chesapeake Bay ................9

Striped bass disease overview for the past ten years plus.........................................................10

Survey of gametes and juvenile striped bass (Morone saxatilis) for mycobacteriosis 

from the Chesapeake Bay: Sampling methods, external lesions, 

and histopathology................................................................................................................12

Microbiology of gametes and age 0-3 striped bass (Morone saxatilis) ....................................13

Mycobacterial infections in striped bass (Morone saxatilis) from upper and lower 

Chesapeake Bay: 2002 and 2003 pound net studies........................................................15

Epizootiology of mycobacteriosis in Chesapeake Bay striped bass (Morone 

saxatilis): Large-scale field survey.....................................................................................16

Mycobacteriosis in juvenile Atlantic menhaden...........................................................................17

The influence of dietary intake on the progression and severity of mycobacteriosis 

in striped bass (Morone saxatilis) ......................................................................................19

Mycobacteriosis in Chesapeake Bay fishes: Perspectives and questions ..............................20

Initial investigation of the overall health and presence of mycobacteriosis in 

Roanoke River, NC, striped bass (Morone saxatilis) .......................................................22

Mycobacterial infections in striped bass (Morone saxatilis) from Delaware Bay..................23

Tag-recapture data from Chesapeake Bay striped bass indicate that natural 

mortality has increased........................................................................................................25

Epizootic mycobacteriosis in Chesapeake Bay striped bass: What is the fate 

of infected fish? .....................................................................................................................26

Scientific Abstracts 
A historical perspective on diseases 

of striped bass with emphasis on 

mycobacteriosis.

Eric B. May1, John M. Jacobs2, and Anthony Overton3

1

NOAA Living Marine Resources Cooperative Science Center, 

Department of Natural Sciences, University of Maryland Eastern 

Shore, Princess Anne, MD 21653; email: ebmay@umes.edu. 2

NOAA/NOS, National Centers for Coastal Ocean Science, CCEHBR, 

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, 

MD 21654; email: John.Jacobs@noaa.gov. 3East Carolina University, 

Thomas Harriot College of Arts and Sciences, Department of Biology, 

Howell Science Complex, Greenville, NC 27858.

A series of events, beginning in 1985, has preceded this 

current epizootic of mycobacteriosis in striped bass (Morone 

saxatilis). With the decline of Chesapeake Bay striped bass 

stocks and subsequent post-moratorium recovery to record 

numbers, we have had the opportunity to observe processes 

that rarely manifest. No recovery of a fishery has been without 

consequence. We have in Chesapeake Bay the opportunity to 

examine that consequence and ask if there are indicators suggesting that striped bass have exceeded their carrying capacity. Is this a natural result of an expanding stock that, given 

patience, will come into balance?

This paper will present a history of striped bass disease 

in Chesapeake Bay from 1988 to present, including the results 

of previous conferences that addressed the subject in 2000 

and 2003. In the spring and summer of 1988, an outbreak of 

Streptococcal sp. affecting striped bass, weakfish, and bluefish 

occurred bay-wide. Sporadic reports of dead striped bass were 

received by the Maryland DNR Fish Health Program between 

1988 and 1994 with isolates of bacteria obtained, primarily 

gram negative enterics. In this case rafts of dead fish were 

seen at varying locations from the Bay Bridge-Tunnel to Kent 

Island. In the spring of 1994 an isolated outbreak involving 

over 50 fish occurred in the Potomac River at the mouth of 

the Wicomico River. This outbreak was diagnosed as being 

the result of Edwardsiella tarda (Baya et al., 1997). In 1995 a 

second outbreak occurred in the Potomac River; in this case 

affected fish yielded isolates of Aeromonas sp. and Pseudomonas sp.

Coincident with the Pfiesteria piscicida scare in 1997, 

striped bass were found to exhibit similar lesions to those 

seen during previous outbreaks. In this case, however, the 

lesions were reported throughout the Chesapeake Bay. Isolates 

of Mycobacterium sp. were derived from spleen and head 

kidney of fish examined. The severity of the infection often 

dictated the location of lesions seen. Fish exhibited no external 

evidence of infections and those with internal lesions were 

confined to nodules on the spleen, or spleen and liver. In all 

cases where external lesions were manifest, the spleen and 

liver were always infected, and in most the head kidney, heart, 

and gonads were also involved.

In surveys conducted for his doctoral research, Overton 

et al. (2003) examined 217 striped bass where the fish were 

necropsied and examined for presence or absence of external 

and internal evidence of lesions indicative of Mycobacterium

sp. infection. This study suggested that there was a relationship between the severity of infection and both size of the 

fish and condition factor. In all of the cases described above, 

Mycobacterium sp. was confirmed using acid-fast staining; 

thus, species identification was not made.

Investigations conducted by NOAA since the 1970s and 

Maryland DNR scientists since the 1980s have shown that 

disease in fish resident to the Chesapeake Bay is not a new 

phenomenon. The presence of epizootics in Chesapeake Bay 

is also not new; white perch mortalities were observed in the 

Potomac River in the 1960s and in a variety of fish in 1988. 

We will also include recent information suggesting that mycobacterial infections have been with us since 1984 or earlier, 

and that the Edwardsiella tarda epizootic reported in 1994 

may have been, in fact, the consequence of Mycobacterium sp.

Two meetings have been held that have addressed the 

issue, the first on bioenergetics and striped bass (August 2000) 

and the second specifically addressing Mycobacterium sp. 

infections in striped bass (April 2004). During the course of 

these meetings, a list of priority topics was developed which 

included (ranked in order of importance): (1) Determine the 

outcome as a result of infection; (2) Determine the spatial 

extent of the disease; (3) Develop rapid diagnostic method 

for species of concern; (4) Complete Koch’s postulates; (5) 

Determine mode of transmission; (6) Determine predisposing factors; and (7) Address human health issues. Many of the 

technical papers in the 2004 meeting touched on the above 

topics; however, no real conclusions were drawn.

Literature Cited

Baya, A.M., Romalde, J.L., Green, D.E., Navarro, R.B., 

Evans, J., May, E.B., and Toranzo, A.E., 1997, Edwarsiellosis in wild striped bass from the Chesapeake Bay: Journal 

of Wildlife Diseases, v. 33, p. 517-525.

Overton, A.S., Margraf, F.J., Weedon, C.A., Pieper, L.H., and 

May, E.B., 2003, The prevalence of mycobacterial infections in striped bass in Chesapeake Bay: Fisheries Management and Ecology, v. 10, p. 301-308.

   USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
The ecology of mycobacteria infecting 

striped bass (Morone saxatilis) in 

Chesapeake Bay: A research plan.

Howard Kator, Martha Rhodes, and David Gauthier

Department of Environmental and Aquatic Animal Health, Virginia 

Institute of Marine Science, College of William and Mary, Gloucester 

Point, VA 23062; email: kator@vims.edu.

The ecology of mycobacteria in estuarine and marine 

waters remains poorly understood. The current epizootic in 

Chesapeake Bay striped bass and newly described pathogens 

Mycobacterium shottsii and M. pseudoshottsii raise ecological questions that if answered can improve our understanding 

of the pathogenesis of mycobacteriosis in this fish species. 

Questions remain whether these mycobacteria are obligate or 

opportunistic pathogens. Do these species exist as free-living saprophytes in estuarine ecosystems? And if so, is their 

recent success as pathogens in estuarine systems facilitated 

by anthropogenic alterations in water quality such as nutrient 

enrichment or organic pollutants?

The literature describes the environmental occurrence of 

nontuberculous or environmental mycobacteria using the term 

“ubiquitous.” Numerous research papers on Mycobacterium 

marinum, for example, contain statements such as

“.......virtually any water source and water-related 

activity is a potential risk, including tending aquarium, fishing, skin diving, and a number of other 

water-related activities” (Dobos et al., 1999).

Presence does not necessarily imply function, and from 

an aquatic microbial ecology viewpoint such statements provide little insight toward resolution of the immediate question 

raised, e.g., do these organisms participate in processes of 

energy and material flow or behave essentially as passive and 

persistent allochthonous particles? A number of recent papers 

address mycobacterial persistence and dormancy by examining physiological responses to starvation in model species 

such as M. smegmatis. Examples from the literature will be 

provided in this presentation where appropriate with respect to 

the following questions:

Is there an estuarine reservoir of M. shottsii/pseudoshottsii

in Chesapeake Bay?

Ongoing or new research needs to address the question of 

whether or not the dominant microorganisms now infecting striped bass are autochthonous components of Bay 

waters or whether they are allochthonous and transient 

contaminants originating from an external source and happen to infect striped bass. In addition, we need to deter1.

mine if their distribution is similar to that of M. marinum. 

Does virtually any source of water serve as a reservoir for 

the bacterium? And are there animal reservoirs other than 

striped bass?

Are the dominant mycobacteria now infecting striped bass 

obligate pathogens and not found elsewhere in the environment, or are they opportunistic free-living organisms 

in Chesapeake Bay habitats?

If recoverable from Bay environments, isolate virulence 

could be assessed using a fish model or in vitro assays to 

examine the ability of mycobacteria to invade and persist 

in primary cultures of host cells or cell lines, as well as 

cytopathic effect. A recent report suggests that strain 

variation in M. marinum isolates is important to human 

pathogenicity. Knowing the environmental distribution 

and prevalence of M. pseudoshottsii strains possessing 

the IS2404 plasmid associated with mycolactone production could be relevant to the epidemiology of the ongoing 

epizootic.

What are some of the basic autecology questions to be 

addressed for these organisms?

Little is known regarding the autecology of Mycobacterium spp. Some fundamental questions need to be 

addressed, including the following. How do M. shottsii/

pseudoshottsii respond to physicochemical characteristics of estuarine environments? What are the responses 

of these species to abiotic factors such as temperature, 

salinity, and light? What are the effects of nutrients, 

both inorganic and organic, on growth or survival? Can 

saprophytic growth occur in filtered estuarine water 

supplemented with C, N, and P or trace elements such as 

Fe? Can these species utilize hydrocarbons as substrates 

as can saprophytic mycobacteria found in soils? Is the 

growth/persistence of these mycobacteria facilitated by 

nutrient enrichment? Is the mildly alkaline pH of Bay 

water detrimental to these organisms? To what extent can 

persistence under nutrient-limiting conditions be observed 

with these species? As a null hypothesis, can we assume 

protracted persistence in vitro in distilled water? What 

about persistence under environmentally relevant conditions? What are the combined effects of temperature, 

light, and predation on mycobacterial densities? What 

are the rates of inactivation/removal that would provide 

information on temporal boundaries of seasonal infectivity and bacterial survival? Finally, do starved cells demonstrate stress responses similar to those observed in other 

species of bacteria challenged with adverse conditions? 

Is there evidence of an adaptive response? Can dormant 

cells be detected using conventional culture methods? Can 

dormant cells become viable/infective when conditions 

improve?

2.

3.

The ecology of mycobacteria infecting striped bass (Morone saxatilis) in Chesapeake Bay: A research plan.   
What is the distribution of M. shottsii/pseudoshottsii in 

Chesapeake Bay aquatic habitats?

What are possible sources? Can M. shottsii/pseudoshottsii 

be isolated from soils or stormwater runoff? If restricted 

to water, is their distribution dependent or independent of 

salinity or rainfall? Can they be isolated from sewage or 

other types of wastewaters? What is the extent of genomic 

strain variation among isolates and what genetic mechanisms are involved? Are there subtypes across physicalchemical gradients that vary in virulence?

Other specific niche habitats include microlayer, water 

column, and biofilms. Microlayers concentrate nonpolar 

molecules, which may be substrates for mycobacteria. 

Can these organisms be detected in surface water as well 

as below seasonal thermoclines? Can they be found in 

sediment? Biofilms offer unique microenvironments for 

pathogens and provide protection from predators, enhance 

potential to achieve high densities, select for virulent 

strains, and increase the infective dosage. Do swampy 

freshwater areas contiguous with Bay watersheds provide unique habitats of comparatively low pH supporting 

mycobacterial growth?

What is the relationship of M. shottsii/pseudoshottsii to 

other indigenous aquatic microbiota?

Using in situ exposure methods described in the literature, 

it is possible to evaluate the effect of microbial predation 

on these species. However, given the recent literature 

describing how mycobacteria use amoebae as an intracellular refuge for replication, can similar interactions occur 

with the seasonally diverse estuarine microheterotrophic 

plankton community? If so, is there potential for mycobacterial transfer up the food chain as a plausible mechanism to infect tertiary consumers such as striped bass?

Although the research questions articulated above are 

important and relevant, and to some extent testable using conventional cultural methods, it is obvious that efforts to address 

them will be retarded without improved detection/enumeration 

techniques.

The classic problem with enumeration of environmental 

mycobacteria in a mixed microbial community is that existing 

methods for isolation of mycobacteria employ harsh decontaminants that can significantly bias recovery and render quantitative results inaccurate. Moreover, this limitation becomes 

more acute should sample concentration be required. There 

is thus a critical need for improved methods. These include 

development and validation in environmental waters of species-specific polymerase chain reaction (PCR) primer sets 

(and TaqMan probes) for real-time PCR quantitative detection. 

While access to such methods would be extraordinarily beneficial, we cannot ignore that the problem of detecting nonviable cells with PCR will require supplementary approaches to 

confirm cell viability. Use of live/dead penetrating fluorescent 

4.

5. stains, PCRs targeting specific genes or gene products, and 

perhaps developing a workable fluorescent in situ hybridization (FISH) method combining direct counting with a metabolic assay would facilitate the study of mycobacterial ecology 

in aquatic systems.

Understanding the ecology of the mycobacteria infecting 

striped bass is a crucial step toward identifying environmental 

factors and processes that influence the epidemiology of the 

current epizootic.

Literature Cited

Dobos, K.M., Quinn, F.D., Ashford, D.A., Horsburgh, C.R., 

and King, C.H., 1999, Emergence of a unique group of 

necrotizing mycobacterial diseases: Emerging Infectious 

Diseases, v. 5, no. 3, p. 367-378.

Ecology of Mycobacteria Infecting Striped Bass

in Chesapeake Bay

Water Quality

Interactions?

Nutrients,

Petroleum

Biotic Interactions?

Microbiota,

Alternate Hosts,

Internal Reservoirs

Are there external

sources of infecting

mycobacteria?

Sewage?

Domestic animal waste?

Nonpoint runoff?

Wild animals?

What are the 

effects of abiotic

environmental

factors on

mycobacteria?

Effects of:

Psu, °C, Sunlight, 

Particles, O2, Organic

Substrates, Biofilms,

Microlayer

On:

Distribution within Bay,

Growth, Persistence,

Sublethal Stress,

Virulence, Strain

Variation, Detection/

Enumeration

DISEASE

 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Striped bass mycobacteriosis: 

A zoonotic disease of concern in 

Chesapeake Bay.

Frank M. Panek1 and Tanya Bobo2

1

U.S. Geological Survey, Leetown Science Center, National Fish Health 

Research Laboratory, 11649 Leetown Road, Kearneysville, WV 25430; 

email: fpanek@usgs.gov. 2Virginia Department of Health, Division 

of Zoonotic and Environmental Epidemiology, 109 Governor Street, 

Richmond, VA 23219; email: tanya.bobo@vdh.virginia.gov.

In addition to causing disease in many species of freshwater and marine fishes, there are a few fish pathogens that 

are known to be zoonotic, that is, causing disease in humans. 

While the human risk of contracting infection or disease from 

fish pathogens is generally low, an awareness of the potential 

risks is important for fishery managers, anglers, and commercial fishers. One of these pathogen groups that is of increasing 

interest in the Chesapeake Bay Region are the mycobacteria, 

in particular, Mycobacterium marinum, one of the causative 

agents of mycobacteriosis in striped bass (Morone saxatilis) 

and one of the known causes of cutaneous mycobacteriosis in 

humans.

Recent studies by scientists at the National Fish Health 

Research Laboratory and the Virginia Institute of Marine 

Science have shown infection rates in striped bass of up to 

nearly 62% in certain Virginia tributaries to Chesapeake Bay 

(Ottinger et al., 2005). Of the several mycobacteria species 

known to infect Chesapeake Bay striped bass, several are 

known to be zoonotic, including M. marinum and M. fortuitum

(Elko et al., 2004). Previous studies have clearly shown that 

careless handling of infected fish represents a potential health 

risk to anglers, commercial fishers, and fishery management 

workers and that resulting localized skin lesion can be very 

difficult to treat. Immunocompromised individuals can be 

especially at risk of infection (Glaser et al., 1994).

Surveillance for non-tuberculous mycobacteria (NTM) in 

Virginia is conducted by the Virginia Department of Health, 

Division of Disease Prevention. Minimal information is 

collected on NTM including M. marinum. We were able to 

compile some limited reported cases of M. marinum for the 

years 2000 – 2005 from 17 reporting districts within the tidal 

Chesapeake Bay watershed of Virginia. Similar epidemiological data were also available from the Maryland Department 

of Health and Mental Hygiene. In this instance, the Division 

of Medical Microbiology provided a summary of laboratory 

reports from clinical specimens, sorted by the 10 counties 

bordering Chesapeake Bay, from 1995 – 2005. Data from 

both states included age, sex of the patient, and the location or 

nature of the infection (e.g., finger, hand, foot). Neither state 

was able to provide information regarding the mechanisms of 

injury/infection or provide any information on the patient’s 

occupation. We compiled similar data from counties outside 

Chesapeake Bay within both states in order to contrast the 

incidence of cutaneous mycobacteriosis cases in Bay counties to the general population at large. In Virginia, we examined the database of reportable communicable diseases from 

the Central Shenandoah (10 counties) and Central Virginia 

(6 counties) Districts, from 2000 - 2005. In Maryland, we 

examined records from Allegheny and Garrett Counties. In all 

instances, the case numbers reported are raw data not corrected for population size.

During a period from 1995-2005, the States of Virginia 

and Maryland documented 275 cases of M. marinum infections in the human population within the Bay watershed. 

These cases represent a significant increase from earlier investigations regarding NTM disease. A national survey involving 

46 state and local laboratory centers from 33 states and the 

District of Columbia in 1981-1983 documented a national 

average of about 40 cases per year (O’Brien et al., 1987). A 

similar laboratory-based survey initiated in 1993 documented 

an annual national average incidence of about 158 cases with 

most of these reported in the southeast (Dobos et al., 1999). In 

Maryland, the largest number of cases came from Ann Arundel 

(n=106) and Talbot (n=51) Counties. In Virginia, the majority 

of cases originated in the Rappahannock (n=10), Peninsula 

(n=8), and Three Rivers (n=8) reporting districts. The trend 

in reporting shows increases in the fall and winter months 

with the lowest reporting indices in the early spring in both 

states. Most of those infected were males (67%-VA; 67%-MD) 

between the ages of 40 and 70 (79%-VA; 62%-MD) and most 

infections were on hands and fingers (43%-VA; 63%-MD). 

During the same period, only four cases of M. marinum infection were noted in non-Bay counties in both states.

In this paper we discuss the incidence and prevalence of 

mycobacterial infections in striped bass and contrast these to 

epidemiological data collected by the Virginia Department of 

Number of reported human cases of cutaneous mycobacteriosis 

in Maryland and Virginia, 1995-2005

Striped bass mycobacteriosis: A zoonotic disease of concern in Chesapeake Bay.   
Striped bass disease overview for the 

past ten years plus.

Laurence Pieper

Maryland Department of Natural Resources, Fisheries Service, 301 

Marine Academy Drive, Stevensville, MD 21666; email: lpieper@dnr.

state.md.us.

Ulcerative dermatitis syndrome (UDS) was described by 

Sindermann (1988) as caused by multiple species of bacteria 

in many species of fish in saltwater, estuarine, and freshwater 

ecosystems. Bacterial infections have been documented by 

many researchers; these infections cause fish lesions internally 

and externally. Snieszko (1978) reported on mycobacteriosis 

in fish and described a new species found by Ross in salmonids. Sakanari (1983) reported mycobacteriosis in striped bass 

in the San Francisco Bay on the West Coast. In this case the 

disease results in annual mortality.

In 1988 Streptococcus iniae was isolated as the causative 

agent in fish kills in the lower Chesapeake Bay of Maryland. Many species were involved: striped bass, bluefish, sea 

trout, red drum, croaker, and spot. We found the infection in 

bluefish by filleting the fish whereupon pus was found along 

the backbone and in the red musculature area along the dorsal. 

The source for this disease was never ascertained; however, 

this pathogen caused widespread mortality to multiple species. 

This textbook event is what fish pathologists would expect: an 

end result to the disease investigation.

In 1994 a new incident occurred where pound net fishermen from the Choptank and Potomac Rivers reported striped 

bass with lesions. The Aquatic Animal Health (AAH) group 

responded to these reports and transported fish to the Maryland Department of Agriculture’s (MDA) Animal Health 

Laboratory in College Park, Maryland. Edwardsiella tarda

was isolated from the fish. The superficial lesions associated 

with the infection were hemorrhagic and bilateral on the fish. 

The AAH personnel went to reinvestigate the problem in 

subsequent years (1995-1996). A sampling protocol was initiated: a total of 10-12 symptomatic fish and 2-3 normal control 

fish were collected at each site per trip and delivered to the 

MDA Animal Health Laboratory in College Park, Maryland. 

E. tarda could not be found in all the fish collected; however, 

many other bacterial agents were found. Some of the genuses 

were Aeromonas, Pseudomonas, Streptococcus, and Vibrio to 

mention a few, all of which were isolated from striped bass 

exhibiting lesions.

Field sampling for 1997 coincided with the Maryland 

Department of Natural Resources (MDNR) Striped Bass Stock 

Assessment (SBSA) fall tagging survey, which takes place 

during the fall striped bass season in the Chesapeake Bay. 

Health and the Maryland Department of Health and Mental 

Hygiene of the occurrence of cutaneous mycobacteriosis in 

the human population in the tidal Chesapeake Bay drainage. 

While we are unable to demonstrate any cause-and-effect relationships between the epizootic of mycobacteriosis in striped 

bass and the occurrence of higher than normal incidences of 

NTM cutaneous infections in the human population of the Bay 

counties, the weight of evidence suggests reason for concern. 

Therefore, we recommend that State and Federal fishery 

management authorities work with public health officials to 

increase awareness on the part of fishery workers, anglers, 

and commercial fishers on the potential risks of mycobacterial 

infections. Fishery workers, including management biologists 

and researchers, should not handle infected striped bass if they 

have cuts, abrasions, or sores on hands. We recommend that 

individuals handling or processing fish utilize basic precautions such as wearing gloves and properly washing hands 

after handling fish. Individuals that are immunocompromised 

should seek medical direction before working with infected 

fish.

Literature Cited

Dobos, K.M., Quinn, F.D., Ashford, D.A., Horsburgh, C.R., 

and King, C.H., 1999, Emergence of a unique group of 

necrotizing mycobacterial diseases: Emerging Infectious 

Diseases, v. 5, no. 3, p. 367-378.

Elko, L.E., Rosenbach, K., and Sinnott, J., 2004, Cutaneous 

manifestations of waterbourne infections: Current Infectious 

Disease Reports, v. 5, p. 398-406.

Glaser, C.A., Angulo, F.J., and Rooney, J.A., 1994, Animal 

associated opportunistic infections among persons infected 

with the human immunodeficiency virus: Clinical Infectious 

Disease, v. 18, p. 14-24.

O’Brien, R.J., Geiter, L.J., and Snider, D.E., 1987, The 

epidemiology of nontuberculous mycobacterial diseases 

in the United States: Amer. Rev. Resp. Disease, v. 135, 

p. 1007-1014.

Ottinger, C.A., Blazer, V.S., Densmore, C. L., Gauthier, D.T., 

Kator, H., Panek, F.M., Rhodes, M.W., and Vogelbein, W., 

2005, Mycobacteriosis in Chesapeake Bay Striped Bass 

(Morone saxatilis), in: Cipriano, R.C., Shchelkunov, I.S., 

and Faisal, Mohamed, eds., Health And Diseases Of Aquatic 

Organisms: Bilateral Perspectives: East Lansing, Michigan, 

Michigan State University Press, p. 238-243.

10 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Fish were collected from pound nets located at Tall Timbers 

in the Potomac River; the main bay north of Point Lookout, 

Kent Island; and an area near Rock Hall, Maryland. The 

sampling protocol continued and fish were collected at each 

site per trip and delivered to MDA Animal Health Laboratory 

in College Park, Maryland. The lesions on the fish were of a 

different characteristic than those seen in 1994-1995; early in 

the sampling 15-20% of the striped bass had severe erosive 

lesions and the dermis more eroded on many of the fish to the 

point that the muscle layer was visible. Later in the fall signs 

of healing were seen on some fish and the number of individuals showing lesions had diminished significantly (5-10%), 

perhaps due to the drop in water temperature. Histological 

results revealed that the fish with lesions and control fish had 

granulomas in the spleen, anterior kidney, and liver. A gram 

stain of the histological slides revealed gram positive cocci; an 

acid-fast stain revealed acid-fast positive rods in many of the 

granulomas in the spleen, head kidney, and liver. The MDA 

Animal Health Laboratory in College Park, Maryland, isolated 

S. iniae and a new species of mycobacterium, M. chesapeakii. 

The incident is distinct because the disease is species specific 

and caused no mortality, unlike the 1988 streptococcus event.

The Fish and Wildlife Health (FWH) program of the 

MDNR in 1998 changed the sampling protocol to a modified random sampling design, which is used to the present 

time. The first 10 fish out of the pound net were collected for 

examination. Additionally, the sampling design was expanded 

and striped bass were collected from gill net and hook and line 

surveys. External lesions were no longer erosive and severe in 

nature but had returned to the superficial nature seen previous 

to 1997. Some individual fish manifested few or no external 

signs of disease. In advanced stages, though, emaciation, 

exophthalmia, hemorrhagic and dermal ulcerative lesions, or 

loss of scales may be observed. The prevalence of emaciation 

increased in 1998 and 1999; however, in 2000 the rate of emaciated individuals decreased and to date has not been observed 

at the previous level.

The observed infection rate of mycobacteriosis has 

increased over the past 5 years to a high of 62% of the fish 

examined. Additionally, streptococcus, vibrio, micrococcus, 

and enterococcus have been isolated. This array of bacteria has 

been causing a multiple infection for the fish and the immune 

system of these individuals must be challenged. Observed 

overall condition of the fish has improved slightly and not as 

many emaciated fish have been seen; lesion prevalence has 

dropped to 5%. There is still no mortality associated with this 

disease syndrome, unlike the textbook cases from 1988 and 

2000.

This disease of striped bass has eluded researchers to 

date. At present there is no textbook event associated with 

this disease. The specific cause has not been identified, yet 

researchers have identified numerous genera of bacteria 

involved and numerous species of some genera found associated with affected fish. The effect has been identified with 

numerous clinical signs: emaciation, exophthalmia, hemorrhagic and dermal ulcerative lesions, internal lesions, paraStriped bass disease overview for the past ten years plus. 11

sites, and lesions and granulomas in internal organs. Yet, no 

end result from this disease can be declared at this point. There 

is no direct evidence of mortality associated with mycobacteriosis or ulcerative dermatitis syndrome.

What we know:

External lesions may or may not be present and are not 

always indicative of mycobacteriosis; lesion prevalence has dropped to 5%.

Multiple infections with other bacteria present internally along with mycobacteriosis.

Mycobacteriosis prevalence is up from 1998 to 62% in 

2005 and is species specific.

There is no mortality associated with this mycobacteriosis infection, unlike that on the West Coast.

Striped bass population is at an all-time record high. 

Disease could be an indication of an overpopulation 

problem and an insufficient forage base.

Literature Cited

Sakanari, J. A., Reilly, C.A., and Moser, M., 1983, Tubercular 

lesions in pacific coast populations of striped bass: Transactions of the American Fisheries Society, v. 112, p. 565-566.

Sindermann, C.J., 1988, Epizootic ulcerative syndromes in 

coastal/estuarine fish: NOAA Technical Memorandum 

NMFS-F/NEC-54.

Snieszko, S.F., 1978, Mycobacteriosis (Tuberculosis) of 

fishes: U.S. Fish and Wildlife Fish Disease Leaflet 55, 

p. 1-9.

•

•

•

•

•
Survey of gametes and juvenile 

striped bass (Morone saxatilis) for 

mycobacteriosis from the Chesapeake 

Bay: Sampling methods, external 

lesions, and histopathology.

Mark A. Matsche1, Lawrence Pieper2, Cynthia B 

Stine3, Andrew Kane3, Ana Baya4, Kevin Rosemary2, 

Cindy Driscoll2, and John M. Jacobs5.

1

Maryland Department of Natural Resources, Cooperative Oxford 

Laboratory, 904 South Morris Street, Oxford, MD 21654; email: 

mmatsche@dnr.state.md.us, krosemary@dnr.state.md.us, cdriscoll@

dnr.state.md.us.

 2Maryland Department of Natural Resources, Fisheries 

Service, 301 Marine Academy Drive, Stevensville, MD 21666; email: 

lpieper@dnr.state.md.us.

 3Aquatic Pathobiology Center, University of 

Maryland, Department of Veterinary Medicine, 8075 Greenmead Dr., 

College Park, MD 20742; email: cstin001@umaryland.edu, akane@

umaryland.edu. 4Maryland Department of Agriculture Animal Health 

Laboratory, 8077 Greenmead Drive, College Park, MD 20742; email: 

ambaya@umd.edu.

 5NOAA/NOS/Cooperative Oxford Laboratory, 904 

South Morris Street, Oxford, MD 21654; email: John.Jacobs@noaa.gov.

A survey of striped bass (Morone saxatilis) in the Chesapeake Bay since 1998 has revealed the prevalence of mycobacterial infection from 25-60%. Surveyed fish were collected 

primarily from commercial pound nets and were generally 3 

years old or older. While this survey provides a useful index of 

disease in the harvestable segment of the population, information on younger fish is lacking. To fill this gap, we initiated a 

study to provide data from age 0-3 fish. In addition, gamete 

samples from ripe striped bass were collected for mycobacterial primary isolation to examine the possibility of vertical 

transmission.

Gametes were collected from ripe fish from the Nanticoke and Choptank Rivers in 2003-04 for assessment of 

the presence of Mycobacterium sp. Sixty fish (30 males, 30 

females) were collected by electro-fishing from each river during the month of April. Stunned fish were netted from the river 

and transferred to a holding tank containing tricaine methanosulfonate (MS222) for sedation. The vent of each fish was 

disinfected with 70% ethyl alcohol (ETOH) prior to collection 

of gametes. From each male, approximately 15 mL of milt 

was expressed directly into sterile Falcon centrifuge tubes. 

From each female, approximately 5 mL of eggs were collected 

using modified 5-mL sterile serological pipettes. The tip of 

each pipette was broken off, the filter media was removed, and 

the blunt end was disinfected with 70% ETOH and inserted 

into the vent, and light suction was applied. Gamete samples 

were transported chilled to the Cooperative Oxford Labora12 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

tory (COL), frozen, and shipped to the University of Maryland 

Aquatic Pathobiology Center (APC) for bacterial culture.

Juvenile fish from three areas of Maryland’s portion of 

the Chesapeake Bay, including the upper Bay, the lower Choptank River, and the lower Potomac River, were surveyed for 

mycobacteria infection. Young-of-year (YOY) fish were collected by beach seine from at least two sites from within each 

area. YOY fish from the upper Bay were collected from sites 

in the lower Sassafras River. Thirty fish were collected from 

each site and transported live to the APC for necropsy. The 

examination included: gross lesion incidence; parasite abundance; bacterial culture of brain, liver, and anterior kidney; 

and mycobacterial culture from spleen. Thirty additional fish 

collected from each site were transported live to COL, sacrificed with an overdose of MS222, and necropsied, and tissue 

samples were preserved in 10% neutral buffered formalin. 

Fish of each age class (1 through 3) were collected from each 

area by hook-and-line, transported to either the APC or COL, 

and processed as previously described. Upper Bay fish were 

collected from an area called “Love Point,” which is bounded 

by the mouth of the Chester River and main stem of the Bay.

Preserved fish tissues were processed for routine histology and stained with haematoxylin and eosin. Adjacent tissue 

sections were stained using aqueous acid-fast for acid-fast 

bacteria. Samples of spleen, liver, and anterior kidney were 

collected aseptically and processed for bacterial culture. 

Spleen, liver, and anterior kidney were chosen for culture 

based on results from previous striped bass surveys conducted 

from 1998-2002; 98% of these fish examined were positive for 

mycobacteria in at least one of these organs.

The prevalence of external lesions on fish in 2003 was 

2.3% (N=43) for age-1 fish, 1.8% for age-2 fish, and 0% 

(N=24) for age-3 fish. In 2004, the prevalence of external 

lesions was 12.0% for age-1 fish (N=184) and 13.2% for age-2 

fish (N=174).

In analysis, fish were considered to be positive for mycobacteria if acid-fast bacilli were evident in granulomas from 

any tissue. In all age classes, granulomas were occasionally 

observed that contained visible elements of parasites, non-specific staining from acid-fast procedure, or no acid-fast bacilli. 

Severity of infection was assessed by number of organs with 

granulomas containing acid-fast bacilli per organ: 1- focal 

granuloma, 2- two to six granulomas, and 3- more than six 

granulomas.

Prevalence of mycobacteria, detected by acid-fast positive granulomas, was compared by age and gender as well as 

age and location. Analysis consisted of 2x2 contingency table 

tests for homogeneity, with the Yates-corrected chi-square test 

if there was a large enough sample size (N for each cell >5) or 

Fisher’s exact test for binomials (N of at least one cell <5).

No granulomas containing acid-fast bacilli were detected 

in YOY collected in 2003 (N=212) or 2004 (N=213). In 

2003 and 2004, no differences were detected in prevalence 

of mycobacteria by region or gender in age-1 through age-3 

fish. In 2003, Bay-wide prevalence of mycobacteria was 16% 

for age-1 (N=43), 24% for age-2 (N=112), and 25% for age-3 
(N=24) fish. Analysis of prevalence by age class (Fisher exact 

test) indicated that prevalence of mycobacterial infection was 

significantly lower in age-0 fish than all other age classes. 

No differences in prevalence of mycobacterial infection were 

detected however, between age-1, age-2, and age-3 fish, which 

may be the result of low sample sizes. In 2004, Bay-wide 

prevalence of mycobacteria was 13% for age-1 (N=184), 

20% for age-2 (N=174), 57% for age-3 (N=7), and 73% for 

age-4 (N=11) fish. Analysis indicates that mycobacterial 

infection was significantly lower in prevalence in age-0 fish 

than all other age classes, and that age-3 and age-4 fish were 

significantly higher in prevalence than age-1 and age-2 fish. 

No difference was detected between age-1 and age-2 fish, 

or between age-3 and age-4 fish. There was an insufficient 

number of parasite observations from fish collected in 2003 

and 2004 to allow comparisons to be made between infected 

and uninfected fish.

Severity of infections was characterized by organ 

involvement. In 2003, of fish with organ involvement (N=41), 

granulomas with acid-fast bacilli were evident in 82.9% of 

spleens, 39.0% of anterior kidneys, and 19.5% of livers. In 

2004, this trend generally continued as granulomas were 

observed in 85.0% of spleens (N=71), 54.0% of anterior 

kidneys (N=70), and 14.0% of livers (N=71). The average 

number of organs involved in infected fish in 2003 was 1.6 for 

age-1 and 1.4 for age-2 fish. The average ranking of numbers 

of granulomas with acid-fast bacilli in infected organs was 

0.67 for age-1, 1.02 for age-2, and 0.83 for age-3 fish in 2003. 

In 2004, average rank was 1.1 for both age-1 and age-2 fish.

In summary, mycobacteria were first detected in age-1 

fish by histopathology. Histological data suggest a trend of 

increasing prevalence of mycobacteria infection with age, 

although significant differences were not detected between all 

age classes. Prevalence of infection among juvenile striped 

bass does not differ by gender or region in Maryland’s portion 

of the Chesapeake Bay. Infection is most evident in spleen, 

then anterior kidney, and then liver. The incidence of external 

lesions appears very similar among age 1-3 striped bass.

Microbiology of gametes and age 0-3

striped bass (Morone saxatilis).

Cynthia B. Stine1,2, Andrew S. Kane1,2,3, Mark 

Matsche4, Larry Pieper4, Kevin Rosemary4, John M. 

Jacobs5, John Abel6, Cindy Driscoll4, Ana M. Baya2,6

1

Aquatic Pathobiology Center, University of Maryland, 8075 Greenmead 

Drive, College Park, MD 20742; email: cstin001@umaryland.edu, 

akane@umaryland.edu. 2Department of Veterinary Medicine, 

University of Maryland, 8075 Greenmead Drive, College Park, MD 

20742. 3Department of Epidemiology and Preventive Medicine, 

University of Maryland School of Medicine, Baltimore, MD. 4Maryland 

Department of Natural Resources/Cooperative Oxford Laboratory, 

904 South Morris Street, Oxford, MD 21654; email: MMatsche@

dnr.state.md.us, LPieper@dnr.state.md.us, KRosemary@dnr.state.

md.us, CDriscoll@dnr.state.md.us. 5NOAA/NOS/Cooperative Oxford 

Laboratory, 904 South Morris Street, Oxford, MD 21654; email: John.

Jacobs@noaa.gov. 6Maryland Department of Agriculture Animal 

Health Laboratory, 8077 Greenmead Drive, College Park, MD 20742; 

email: jmiltabell@aol.com, ambaya@umd.edu.

Mycobacteriosis in Chesapeake Bay striped bass (Morone 

saxatilis) was first reported in 1997. Recent reports indicate 

that up to 76% of fish can be infected with mycobacteria in 

certain regions of the Bay. However, infection prevalence is 

believed to increase with age and published studies have concentrated on prevalence in older fish. This study examined the 

prevalence of mycobacterial infection in gametes and 0-3 year 

old striped bass, and was designed to identify possible risk 

factors associated with mycobacterial infection.

Gametes from ripe/spawning males and females were 

non-destructively collected in the field using a sterile catheter 

from spawning stock in the Choptank and Nanticoke Rivers in 2003 and 2004. Young-of-the-year striped bass were 

collected by beach seine in the upper Bay and the Choptank, 

Nanticoke, and Potomac Rivers in 2003 and 2004, and in the 

Pocomoke River in 2004. Older (1-3 year old) fish were collected by hook and line from the upper Bay and the Choptank 

and Potomac Rivers in 2003 and 2004, and by pound net in 

the Pocomoke River in 2004. Live fish were transported to 

the laboratory for aseptic necropsy with observations taken 

on gross pathology and parasitology, and samples taken for 

general bacteriology, mycobacterial culture, and histology.

Samples of brain, liver, and anterior kidney were used to 

inoculate 1% Tripticase Soy Broth (TSB) and 1% Tripticase 

Soy Agar (TSA). Growth in TSB was streaked on TSA for 

isolation and identification. Resulting colonies were identified 

by routine bacteriology, biochemical reactions within analytical profile index strips, and fatty-acid methyl ester (FAME) 

analysis by capillary gas chromatography. Portions of spleens 

were aseptically removed for mycobacterial isolation. Spleens 

Microbiology of gametes and age 0-3 striped bass (Morone saxatilis). 13
Area

2003 2004

Myco Yeast

P. Fluorescens MycoMicrococcus

Choptank 3 (65) 22 (65) 8 (65) 2 (52) 8 (52)

Nanticoke 11 (62) 5 (62) 2 (62) 5 (60) 0 (60)

were homogenized in Tris-EDTA buffer, diluted in BPBS, 

and plated on Middlebrook agar supplemented with oleic 

acid, albumin, dextrose, and catalase enrichment. Plates were 

checked for growth every week for 8-12 weeks. Colonies with 

morphology consistent with mycobacteria were tested for 

Ziehl–Neelson acid-fastness. Characteristic acid-fast positive 

colonies were streaked for isolation on Middlebrook agar, 

and when sufficient growth occurred, were analyzed by gas 

chromatography FAME analysis for putative species identification. Gametes were processed for mycobacterial isolation as 

described for splenic tissue as 0.5 mL of gametes were homogenized in 2 mL BPBS.

Gametes sampled in 2003-2004 were infected with 

mycobacteria, Pseudomonas fluorescens, Micrococcus spp., 

and unidentified yeast. Prevalence data for these findings are 

presented below (sample sizes in parentheses).

mycobacteria than 3 year olds (p=0.02). No differences among 

rivers were found within 2- and 3-year-old fish in 2004. 

However, the prevalence in 1-year-old fish in the Potomac was 

lower than that in the upper Bay (p=0.04) and the Pocomoke 

River (p=0.0003). These differences prevent collection-wide 

age analysis for 2004. Parasite or gross pathology observations 

were not found to be risk factors for infection with mycobacteria. General microbiology results indicated that, other than 

mycobacteria, 1-3 year old striped bass harbor fewer bacterial 

pathogens compared with young-of-the-year striped bass.

Preliminary results indicate that sampling both anterior 

kidney and spleen tissue, versus sampling only one organ, 

provides optimal identification of mycobacteria culture-positive fish (observed agreement=0.80). Additionally, the gonads 

of this age group (1-3 year olds) do not appear to be infected 

with mycobacteria.

The FAME analyses used for general bacterial identification and preliminary mycobacterial speciation are part of the 

Sherlock Microbial Identification System (MIDI Inc., Newark, 

DE), an automated method of bacterial speciation used in conjunction with gas chromatography. However, a large majority 

of environmental mycobacteria are not in the database. Since 

1999, our laboratory has amassed over 600 mycobacterial 

samples isolated from wild, aquarium, and aquacultured fish 

in Maryland. Based on chromatograms from these isolates, 

our laboratory has been able to create a dendogram (i.e., visual 

clusters) of these mycobacterial isolates based on possible species groupings. Preliminary analyses have identified a portion 

of these isolates as M. marinum, M. fortuitum, M. chelonae, 

M. gordonae, M. szulgai, M. scrofulaceum, M. interjectum, M. 

triplex, M. septicum, M. rhodesia, M. duvalii, M. poriferae, 

and the M. chesapeakii-shottsii-pseudoshottsii complex. This 

method, still under development, allows unknown samples to 

be tracked and matched against existing known samples for 

identification, and may be instrumental in following specific 

mycobacterial strains in future epidemiologic studies.

In summary, microbiology data suggest that juvenile 

striped bass are minimally infected with mycobacteria, 

whereas up to 50% of 1-3 year olds in certain areas can be 

infected. Excluding the young-of-the-year fish, prevalence of 

culturable mycobacterial infection within sampled areas tends 

to decrease with age, which is contrary to prevalence data 

based on the presence of granulomas with acid-fast bacteria. 

Gas chromatography FAME analyses indicate Chesapeake 

Bay striped bass are infected with several species of mycobacteria, as are other wild-caught Chesapeake Bay fish species. 

Additionally, young-of-the-year striped bass carry several 

bacterial pathogens other than mycobacteria, whereas 1-3 year 

olds are relatively free of such pathogens. Currently, no risk 

factors have been associated with mycobacterial infection in 

this preliminary analysis.

Support for this study was provided by the Maryland 

Agriculture Experiment Station (MAES), the National Oceanic and Atmospheric Administration (NOAA), the Maryland 

Department of Health and Mental Hygiene, and the Centers 

for Disease Control and Prevention (CDC).

14  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

A difference between rivers was found in the prevalence 

of the yeast in 2003 (p=0.008) and the Micrococcus spp. in 

2004 (p=0.04). No gender difference was found with any of 

the putative pathogens. Neither the yeast, nor P. fluorescens, 

nor the Micrococcus spp. was identified as a risk factor for 

mycobacterial infection by statistical tests for homogeneity.

Young-of-the-year striped bass were also infected with 

mycobacteria. One fish from the upper Bay (N=60) was positive in 2003. In 2004, one fish from the upper Bay (N=60) and 

one from the Choptank (N=60) were positive. Additionally, 

25% of young-of-the-year striped bass from the Pocomoke 

(N=12) were positive. The young-of-the-year collected in the 

Pocomoke River had a higher prevalence than those collected 

in the other areas combined (p=0.0008). General microbiology 

results indicated that a notable proportion of these youngof-the-year fish were positive for other bacterial pathogens, 

including Photobacterium damsela, Pleisomonas shigelloides, 

Aeromonas hydrophila, and several Vibrio species.

One-year-old striped bass appeared to have the highest 

prevalence of cultureable mycobacteria in all rivers sampled 

(see prevalences in table below; sample sizes in parentheses).

No differences among rivers were found within age 

groups in 2003, and analysis by age indicated 1 year olds were 

over seven times more likely to be infected with culturable 

Area Year Age 1 Age 2 Age3

Choptank 2003 22 (37) 14 (59) 8 (12)

2004 13 (23) 6 (16) -

Potomac 2003 0 (5) 0 (1) 0 (10)

2004 0 (19) 0 (14) -

Upper Bay 2003 33 (3) 9 (44) 0 (15)

2004 27 (11) 11 (18) 0 (1)

Pocomoke 2004 53 (17) 33 (6) 0 (2)
Mycobacterial infections in striped 

bass (Morone saxatilis) from upper and 

lower Chesapeake Bay: 2002 and 2003

pound net studies.

Christopher A. Ottinger

U.S. Geological Survey, Leetown Science Center, National Fish Health 

Research Laboratory, 11649 Leetown Road, Kearneysville, WV 25430; 

email: cottinger@usgs.gov.

In the fall of 2002 and 2003 striped bass were obtained 

from commercial pound nets located at the mouths of the 

Nanticoke (11/22/2002, 11/3/2003), Potomac (11/21/2002, 

11/6/2003), Rappahannock (11/8/2002, 11/6/2003), and York 

Rivers (11/14/2002, 11/12/2003). Fifty fish were obtained in 

each sample. Nets were fished for approximately 24 h. Live 

striped bass were removed from the nets and transported to 

shore in a water tank fed by pumped surface water. Prior to 

necropsy, fish were weighed and measured for total length. 

Spleen portions were aseptically removed for bacterial culture. 

Following necropsy, fish were eviscerated and weighed for 

condition factor calculation (K = (eviscerated weight/total 

length3) x 104; Clark, 1927). Recovery of bacteria from aseptically harvested spleen portions was performed as described 

by Rhodes et al. (2004) following the protocol for aseptically sampled internal sites in fish. Unlike in the procedure 

described by Rhodes et al. (2004), culture plates were not 

duplicated. Homogenates were diluted 10-fold in Butterfield’s 

dilution buffer and 200 μL aliquots of the original homogenate 

and dilutions were plated on Middlebrook agar for colony 

enumeration and primary isolation. In 2002, the dilution series 

was determined based on the presence of granulomas in the 

spleen as seen in macroscopic examination. When granulomas 

were present, dilutions were made through 1 x 104. Dilutions 

were made to 1 x 102 when granulomas were not observed. 

In 2003 all dilution series were made through 1 x 104. The 

acid-fast bacilli insolated in 2003 were characterized using 

the bacteriologic biochemical methods described by Rhodes 

et al. (2004). The acid-fast bacilli isolated in 2002 were not 

characterized. Individual spleen mycobacterial infection 

was indicated by a positive bacterial culture. Prevalence of 

infection was defined as the percentage of individuals in a 

sample that exhibited colonies of acid-fast bacilli in spleen 

cultures. Intensity of bacterial infection was defined as the 

number of colony forming units (CFU) g-1 spleen. Differences 

among sample total length and condition factor were evaluated by analysis of variance (ANOVA) with pair-wise post hoc 

(Tukey) comparisons where appropriate. Differences among 

sample mycobacterial infection intensities were evaluated 

using cross tabulation (2 x 4) with Pearson chi-square. Bacterial infection intensity was evaluated using Kruskal-Wallis 

one way analysis of variance. Differences were considered 

statistically significant when p ≤ 0.05. Sample size for the 

mycobacteria cultures was reduced as a result of plates lost 

from overgrowth by non acid-fast organisms. Only data sets 

that included culture results were included in data analysis. In 

some instances, colony numbers were too numerous to count. 

Data for these fish were included in the determination of infection prevalence but not infection intensity. Data were pooled 

for the upper (Nanticoke, Potomac) and lower (Rappahannock, 

York) Bay.

In 2002, striped bass total length (n, mean ± SD) for the 

upper (80, 475.6 ± 59.7) and lower (76, 529.1 ± 59.2) Bay 

were significantly different. The condition of all fish analyzed 

was significantly higher in the upper Bay (79, 0.830 ± .097) 

than the lower (76, 0.787 ± .097). Mycobacterial infection 

prevalence (n, percent) for the upper (80, 46.2%) and lower 

(76, 41.3%) Bay was not significantly different. Infection 

intensity (n, median CFU) for the upper (35, 52,200) and 

lower (32, 40,500) Bay was not significantly different. In both 

the upper and lower Bay, mycobacteria infected fish had significantly reduced condition relative to noninfected fish from 

the same area (n, mean ± SD: upper infected = 0.801 ± 0.098; 

upper noninfected = 0.857 ± 0.089; lower infected = 0.747 ± 

0.093; lower noninfected = 0.816 ± 0.091). There was no significant difference in the length of infected versus noninfected 

striped bass in either region. In the 2003 samples, striped bass 

total length (n, mean ± SD) for the upper (75, 452.7 ± 75.2) 

and lower (89, 504.5 ± 83.9) Bay were significantly different. 

The condition of all fish analyzed was significantly lower in 

the upper Bay (75, 0.849 ± .117) than the lower (89, 0.956 ± 

.099). Mycobacterial infection prevalence (n, percent) for the 

upper (75, 68.0%) and lower (89, 62.9%) Bay was not significantly different. Infection intensity (n, median CFU) for the 

upper (51, 160200) and lower (56, 18500) Bay was significantly different. In the upper Bay, mycobacteria infected fish 

had significantly reduced condition relative to noninfected fish 

(n, mean ± SD: infected = 51, 0.814 ± 0.119; noninfected = 24, 

0.926 ± 0.066). The condition of mycobacteria infected striped 

bass (n, mean ± SD) from the lower Bay (56, 0.955 ± 0.088) 

was not significantly different from that of the noninfected 

fish (33, 0.957 ± 0.116). There was no significant difference in 

the length (n, mean ± SD) of infected (56, 517.0 ± 84.6) versus 

noninfected (33, 483.3 ± 79.5) striped bass in the lower region. 

In the upper region of the Bay the infected fish (n, mean ± SD) 

were significantly larger (51, 477.7 ± 75.0) than noninfected 

fish (24, 399.6 ± 40.5). Characterized mycobacteria from the 

2003 samples were predominantly (prevalence and intensity) 

Mycobacterium shottsii in both the upper and lower regions of 

the Bay.

Results from the fall 2002 and 2003 samples suggest 

some annual variation in mycobacterial infection. Differences 

were observed between regions of the Bay with the most 

prominent difference observed in 2003. As previously reported 

(Overton et al. 2003), infection maybe associated with reduced 

Mycobacterial infections in striped bass (Morone saxatilis) from upper and lower Chesapeake Bay. 15
Epizootiology of mycobacteriosis in 

Chesapeake Bay striped bass (Morone 

saxatilis): Large-scale field survey.

David T. Gauthier1, Robert Latour1, and Wolfgang 

Vogelbein1

1

Virginia Institute of Marine Science, The College of William and Mary, 

1208 Greate Rd., Gloucester Point, VA 23062; email: gauthier@vims.

edu.

Striped bass in Virginia and Maryland waters of Chesapeake Bay are experiencing an ongoing epizootic of mycobacteriosis. Visceral disease prevalence exceeding 50% has 

been reported in several locations by various authors, and skin 

lesion prevalence exceeding 30% has been observed. The high 

prevalence of skin lesions observed in Chesapeake Bay striped 

bass is unusual and has not, to our knowledge, been reported 

previously in wild fishes. It is alarming, as it may indicate that 

fish are progressing from chronic, covert infection to active, 

lethal disease. We have, however, observed putative healing 

lesions, so the prognosis of striped bass with skin lesions is 

unclear.

Various surveys continue to report high prevalence of 

mycobacterial disease in Chesapeake Bay striped bass; however, the overall picture regarding the scope and severity of 

the current epizootic remains unclear. The widespread nature 

of this epizootic, coupled with the highly migratory nature of 

striped bass, dictates that surveys with large spatial and temporal coverage must be employed to gain a better understanding 

of the disease on a population level. Further, surveys must be 

multi-year in nature in order to assess whether the epizootic is 

worsening, improving, or remaining constant over time.

Since 2003, we have been conducting a survey of 

mycobacteriosis in striped bass in Chesapeake Bay using 

the Chesapeake Bay Multispecies Monitoring and Assessment Program (ChesMMAP) platform (http://www.fisheries.

vims.edu/chesmmap/). The ChesMMAP survey is intended 

to develop data on the distribution and feeding habits of fish 

species in Chesapeake Bay, and to apply these data to development of comprehensive multispecies management models. 

By virtue of its design and scale, this survey also provides 

an ideal sampling platform for studying disease in wild fish. 

Adult finfish are collected via balloon otter trawl five times 

per year over the entire Bay, ranging from the Bay mouth to 

the Susquehanna flats. Sampling is performed in 20-minute 

tows at 90 stations per cruise, with a stratified random design 

that covers all depths. Data collection on fish includes basic 

morphometrics (length, weight, eviscerated weight), otolithdetermined age, and gut content analysis. In addition, comprehensive environmental data are collected at each station. 

condition factor and larger fish may have a greater probability 

of being infected (Overton et al. 2003, Rhodes et al. 2004). 

Although multiple Mycobacterium spp. were infecting the 

striped bass sampled, Mycobacterium shottsii was the most 

prominent species.

Literature Cited

Clark, F.N., 1927, The weight-length relationship of the California sardine (Sardina caerulea) at San Pedro: California 

Division of Fish and Game Fish Bulletin No. 12, p. 1-59.

Overton, A.S., Margraf, F.J., Weedon, C.A., Pieper, L.H., and 

May, E.B., 2003, The prevalence of mycobacterial infections in striped bass in Chesapeake Bay: Fisheries Management and Ecology, v. 10, p. 301-308.

Rhodes, M.W., Kator, H., Kaattari, I., Gauthier, D., Vogelbein, 

W., and Ottinger, C. A., 2004, Isolation and characterization 

of mycobacteria from striped bass Morone saxatilis from 

Chesapeake Bay: Diseases of Aquatic Organisms, v. 61, 

p. 41-51.

16 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Mycobacterial disease status in striped bass is determined 

by histologic detection of granulomas, and severity index is 

calculated as granulomas/mm2 of spleen.

From 2003-2005, disease status was determined for 1,645 

fish. Ages ranged from 0 to 16, with a male/female ratio of 

~3:2. In all 3 years of the survey, the first (late March) and last 

(late October) cruises of the year represented the majority of 

samples, but significant numbers of striped bass were also collected during summer (May-September) months.

Logistic regression analysis of 2003-2005 data indicates 

that risk of disease increases with age in both male and female 

fish, but per-year risk is significantly higher for male fish. 

Mycobacterial granulomas are observed in age-1 fish, indicating that sufficient risk factors are present within the Bay for 

expression of disease. The higher per-year disease risk of male 

fish may in part reflect their longer residence time in the Bay 

relative to females. This confounding influence of age and sex 

on prevalence must be taken into account when examining 

seasonal and regional apparent prevalence data. Regression 

models incorporating age, sex, cruise (season), region, and 

year indicate significant effects of all variables except year 

on disease status. This indicates that, taking other factors into 

account, the overall disease situation in the mainstem Bay was 

constant over the course of the study. Individual analyses of 

cruise and regional effects on disease status are complicated 

by several factors, and will be discussed in this presentation. 

Additionally, the fitting of various models to describe the 

observed apparent prevalence data will be described.

The relationship between mycobacterial disease status 

and fish condition has received considerable attention due to 

emaciation commonly observed in heavily diseased fish. The 

relationship between emaciation and disease in wild striped 

bass is a problem of causality, as equally plausible hypotheses 

can be presented where emaciation (e.g., due to lack of forage 

fish) leads to disease, and vice versa. The causal relationships 

involved here can only be determined by controlled laboratory studies. The association of disease with condition in the 

field, however, can provide useful information as to the overall 

health status of fish in varying stages of disease. Length/

eviscerated weight regression analysis of fish collected via 

the ChesMMAP survey indicated no significant association 

between disease category and weight-at-length (ANCOVA, 

p=0.073). Some nonsignificant depression of weight-at-length 

was observed in severely diseased fish, and comparison of 

Clark’s condition factor K (K=eviscerated weight/length3*105) 

between disease categories indicated significant reduction 

of condition in this group relative to no, minor, and moderate disease categories (ANOVA, p<0.001). These findings 

indicate that in fish collected from the mainstem Bay, disease 

had minor, if any, effects on condition. It should be noted, 

however, that very few emaciated fish were collected via the 

ChesMMAP survey, unlike the larger numbers of these fish 

typically seen in tributaries.

Mycobacteriosis in juvenile 

Atlantic menhaden.

Andrew S. Kane1,2, Cynthia B. Stine2, Laura 

Hungerford1,2, Mark Matsche3, Cindy Driscoll3, Larry 

Pieper4, Kevin Rosemary4, John M. Jacobs4, and Ana 

M. Baya2,6

1

Department of Epidemiology and Preventive Medicine, University 

of Maryland School of Medicine, Baltimore, MD; email: akane@

umaryland.edu, lhungerf@epi.umaryland.edu.

 2Aquatic Pathobiology 

Center, Virginia-Maryland Regional College of Veterinary Medicine, 

8075 Greenmead Drive, College Park, MD 20742; email: cstin001@

umaryland.edu. 3Maryland Department of Natural Resources, 

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, MD 

21654; email: mmatsche@dnr.state.md.us. 4Maryland Department of 

Natural Resources, Fisheries Service, 301 Marine Academy Drive, 

Stevensville, MD 21666; email: lpieper@dnr.state.md.us.

 5NOAA/NOS/

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, 

MD 21654; email: john.jacobs@noaa.gov. 6Maryland Department of 

Agriculture, 8077 Greenmead Drive, College Park, MD 20742; email: 

ambaya@umd.edu.

Concerns have been raised by reports of a high prevalence of mycobacterial infection in striped bass, Morone 

saxatilis, in the Chesapeake Bay. However, the problem may 

be much more extensive with infection among multiple species of Chesapeake Bay fishes, including Atlantic menhaden, 

Brevoortia tyrannus. Atlantic menhaden is a keystone species 

in the Bay and other mid-Atlantic estuaries. They play an 

important ecological role as plankton feeders and are a critical prey species for birds and larger predatory fish including 

striped bass and bluefish. Menhaden also represent the largest 

commercial fishery in the Chesapeake Bay. They are commonly used as bait for “chumming,” and are commercially 

harvested en masse (thousands of tons annually) for their 

protein. This protein is processed for use in animal feeds, as 

well as for their oil. Menhaden oil, which is rich in omega-3 

fatty acids, is widely used in human and veterinary dietary 

supplements, and in cosmetics. The purpose of this study was 

to determine if juvenile Atlantic menhaden in the Chesapeake 

Bay are infected with mycobacteria. Juvenile menhaden were 

examined since they are the primary forage base for many Bay 

animals including striped bass.

An initial laboratory study was conducted with wildcaught juvenile Atlantic menhaden held under laboratory 

conditions. After 10 months, one fish was observed with a 

penetrating external ulcer, and Mycobacterium fortuitum

complex and Mycobacterium spp. were recovered from the 

spleen and the ulcer of this fish, respectively. Subsequently, 

20 additional fish were subsampled from this laboratory group 

to determine the prevalence of the infection. Full necropsies 

Mycobacteriosis in juvenile Atlantic menhaden. 17
with histology were performed and samples were aseptically 

sampled from spleen (homogenized in BPBS), brain, liver, and 

kidney and plated on Middlebrook 7H10 agar supplemented 

with Bacto Middlebrook oleic acid, albumin, dextrose, and 

catalose. Plates were assessed for colony growth after 2-8 

weeks and mycobacteria were identified to the genus level 

based on colony morphology, growth characteristics, and gas 

chromatographic fatty-acid methyl ester (FAME) analyses. 

All 20 fish in the subsample were found to be infected with 

mycobacteria. Three species of Mycobacterium were isolated 

from spleen tissues: M. marinum, M. fortuitum complex, and 

M. gordonae. Granulomas, characteristic of mycobacteriosis, 

were most prevalent in livers, but were also found in spleen, 

posterior kidney, and heart.

In a subsequent field study, Atlantic menhaden were collected by beach seine, cast net, or bank trap from the Choptank, Chicamacomico, Nanticoke, and Pocomoke Rivers of the 

Chesapeake Bay. Live fish were transported in oxygenated, 

insulated coolers to the laboratory for examination and microbiology. Liver tissues were aseptically sampled, homogenized 

in BPBS, and cultured, and mycobacteria were identified as 

described above. Prevalence of culture-positive fish was compared between river systems using Exact tests, with a Bonferroni correction when making multiple, pairwise comparisons

A low percentage (<10%) of the Atlantic menhaden 

sampled had grossly visible, often perianal ulcers, penetrating 

through the skin and the underlying musculature. Histology 

results from a subsample of these specimens indicated that 

these lesions were consistent with ulcerative mycosis. Prevalence of mycobacterial infection differed significantly among 

wild-caught, juvenile Atlantic menhaden, ranging from 2-57% 

by river system (Table 1). Atlantic menhaden from the Chicamacomico River had a higher prevalence (p < 0.001) than 

menhaden sampled from the other river systems.

These studies support the conclusion that multiple species 

of mycobacteria can infect Atlantic menhaden. The relatively 

high prevalence of infection in wild-caught Atlantic menhaden 

is notable since this is one of the most abundant fish species 

in the Chesapeake Bay, and because this species represents 

an essential link in the food chain. The route of infection for 

Atlantic menhaden and other fishes remains unclear although 

horizontal and vertical transmission has been proposed. However, Atlantic menhaden commonly filter-feed on suspended 

sediments, and therefore water and sediment are also possible mechanisms for transfer to the host. Atlantic menhaden 

have previously been noted to be an excellent sentinel species 

for environmental exposure because of their sensitivity to a 

variety of environmental stressors. However, their ability to 

serve as a sentinel for the presence of bacterial pathogens is 

not clear. Demonstration of mycobacterial infection in juvenile 

Atlantic menhaden, both in the laboratory and in the wild, 

raises new questions about the epidemiology of mycobacteriosis in the Chesapeake Bay and the threat it poses to this critical 

keystone fish species.

Support for this study was provided by the Maryland 

Agriculture Experiment Station (MAES), the National Oceanic and Atmospheric Administration (NOAA), the Maryland 

Department of Health and Mental Hygiene, and the Centers 

for Disease Control and Prevention (CDC).

18  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

Table 1. Prevalence data for mycobacteria in Atlantic 

menhaden from four Chesapeake Bay tributaries. Small letters 

indicate significant difference from other river systems at 

p < 0.01 (Bonferroni corrected Fisher Exact probabilities).

River (n) Prevalence (%) 95% Cl

Nanticoke (60) 2a 0.04-8.9

Choptank (134) 10a,b 5.3-16.0

Pocomoke (46) 21b 11.0-36.4

Chicamacomico (47) 57c 42.2-71.7
The influence of dietary intake on 

the progression and severity of 

mycobacteriosis in striped bass 

(Morone saxatilis).

John M. Jacobs1, Ana Baya2, Martha Rhodes1, 

Renate Reimschuessel3, and Reginal M. Harrell4

1 NOAA/NOS Cooperative Oxford Laboratory, Oxford, MD 21654. 2VAMD Regional College of Veterinary Medicine (VMRCVM), University of 

Maryland, College Park, MD 20742-3711. 3USFDA Center for Veterinary 

Medicine, Laurel, MD 20708. 4College of Agriculture and Natural 

Resources, Maryland Agricultural Experiment Station, University of 

Maryland, College Park, MD 20742-5551.

The relationship between the nutritional status of striped 

bass (Morone saxatilis) and the high prevalence of mycobacteriosis in Chesapeake Bay has been the source of much 

concern and speculation in recent years. Yet, basic information 

regarding the influence of nutritional state on the progression 

and severity of the disease in fish is lacking. Here we describe 

preliminary results from the first stage of a long-term challenge study designed to evaluate differential host response 

in experimentally infected fish fed optimal and sub-optimal 

rations.

Hatchery reared striped bass (n = 512, wt = 65 +/- 15 g) 

were introduced to eight 300-gallon recirculating systems 

over the course of 1 month to a final density of 64 fish per 

system. A previous health evaluation from this stock revealed 

a low-level (3/60) background infection with Mycobacterium marinum which was regarded as insignificant with the 

objectives of this study. One month prior to inoculation, fish 

were placed on one of two rations of Melick Aquafeed striped 

bass diet (4 mm) and maintained throughout the course of 

the study at 21 °C, 10 ppt salinity, and pH of 8.2. A factorial 

design was used: replicate high ration control (HRC, 1% body 

weight/d), low ration control (LRC, 0.15% body weight/d), 

and high and low ration treatment (HRM and LRM). Mycobacterium marinum isolated previously from wild striped bass 

was passed through six 30-g fish and recovered from spleen 

homogenates. Experimental fish were inoculated intraperitoneally with 100 μL of either a bacterial suspension resulting in 

a dose of 5-7 x 104 colony forming units (CFU)/g body weight 

(Treatment) or BPBS (Control). A total of 12 fish per ration/

treatment were removed, euthanized, and aseptically sampled 

at inoculation and monthly thereafter. Blood samples were 

collected to determine white and red cell volume, and plasma 

protein levels. Liver and head kidney were cultured on Tryptic 

soy agar and broth. Spleen samples were frozen immediately 

at -20 °C and subsequently homogenized in BPBS and dilution 

plated on Middlebrook 7H10 agar for colony counts. Heart, 

liver, anterior and posterior kidney, spleen, lower intestine, 

gill, and reproductive tissues were preserved in 10% NBF for 

histological preparation and whole carcasses were immediately frozen for subsequent chemical composition analysis. 

Proximate composition consisting of total moisture, neutral 

lipid, protein, and ash were conducted on homogenized 

abdominal tissue. Chemical composition of this region in 

juvenile striped bass has been shown in our lab to be highly 

correlated with total body composition, allowing for estimation of energetic components. All preliminary data analysis 

was conducted using general linear models in SAS v. 9.0 with 

plate count data log transformed.

 Inoculation of M. marinum at 5-7 x 104 CFU/g body 

weight resulted in a differential response among ration groups 

in clinical presentation, mortality, progression, and severity 

of granulomatous inflammation, bacterial density, and whole 

body energy. Grossly, by week 4 the visceral mass of both 

HRM fish was hardened, fused, and occasionally adhered to 

the body wall with nodular red foci apparent throughout the 

visceral fat, mesenteries, and body wall. Spleens were generally enlarged and friable as occasionally were head kidneys. 

By week 8, visceral adhesions and abundance of red foci were 

greatly reduced. Mortality among HRM fish totaled 3% compared to 0% in controls. Lesions were more severe in LRM 

fish, which consistently had ascites, enlarged spleens, and 

more red foci throughout the abdomen. By 10 weeks, 87% of 

LRM fish died compared to 9% of low ration controls. These 

fish generally had a darkened appearance, were emaciated, and 

had pronounced ascites. All remaining low ration fish (n=12) 

were sampled at this time interval and this portion of the study 

terminated.

 Granulomatous inflammation in HRM fish followed a 

classical progression from loosely organized inflammatory 

cells and early granulomas to distinct, well-formed nodular 

lesions as described previously by Gauthier et al. (2003). 

Bacteria were visible at all progressive stages by ZiehlNeelsen staining. By 8 weeks, granulomas were generally well 

developed and rarely found outside spleen, anterior kidney, 

and mesenteric tissue. In contrast, an active, systemic inflammatory state generally persisted throughout the study period in 

LRM fish, characterized by a high prevalence of fused, poorly 

developed granulomas with enlarged, pale necrotic cores. The 

central pale eosinophilic necrotic material was surrounded by 

vacuolated macrophages and the cells comprising the fibrous 

capsules had a thicker, epitheliod morphology, versus the 

flat fibroblastic appearance of those in HRM fish. Acid-fast 

staining generally revealed a greater concentration of bacteria 

in LRM than HRM granulomas. Mortalities were generally 

characterized by systemic infection with intense peritonitis.

The intensity of the response in LRM fish and lack of resolution was associated with consistent splenic bacterial densities 2-3 logs (~108

) (p = 0.001) greater than HRM fish, and a 

moderate decline in total body energy over the study period 

(-67 Kcal). In contrast, energy gain in HRM fish was slightly 

The influence of dietary intake on the progression and severity of mycobacteriosis in striped bass (Morone saxatilis). 19
Mycobacteriosis in Chesapeake Bay 

fishes: Perspectives and questions.

Andrew S. Kane1,2, Laura Hungerford1,2, Cynthia B. 

Stine2, Mark Matsche3, Cindy Driscoll3, John M. 

Jacobs5, and Ana M. Baya2,6

1

Department of Epidemiology and Preventive Medicine, University 

of Maryland School of Medicine, Baltimore, MD; email: akane@

umaryland.edu; lhungerf@epi.umaryland.edu.

 2Aquatic Pathobiology 

Center, Virginia-Maryland Regional College of Veterinary Medicine, 

8075 Greenmead Drive, College Park, MD 20742; email: cstin001@

umaryland.edu.

 3Maryland Department of Natural Resources, 

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, MD 

21654; email: mmatsche@dnr.state.md.us. 4Maryland Department of 

Natural Resources, Fisheries Service, 301 Marine Academy Drive, 

Stevensville, MD 21666; email: lpieper@dnr.state.md.us. 5NOAA/

NOS/Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, 

MD 21654; email: john.jacobs@noaa.gov.

 6Maryland Department of 

Agriculture, 8077 Greenmead Drive, College Park, MD 20742; email: 

ambaya@umd.edu.

Environmental mycobacteria can be pathogenic to a 

variety of fishes and both wild and cultured species transmit 

mycobacteria to humans. As more and more data are amassed 

to better understand mycobacterosis in Chesapeake Bay fishes, 

new questions continue to emerge. The purpose of this abstract 

is to share notions that reveal the complexity of the relationship between environmental mycobacteria and piscine hosts in 

the Bay, and to offer ideas and questions to foster communication and collaboration within the management and research 

communities. Data from two studies will be presented to 

provide additional thoughts on water quality, species involvement, and semantics.

The first study was a controlled laboratory investigation 

of the effects of hypoxia on hybrid striped bass (Morone saxatilis x Morone chrysops) morbidity from mycobacteriosis. We 

identified a cultured population of adult hybrid striped bass 

that tested positive for mycobacteria but were subclinical, that 

is, not exhibiting lesions or grossly observable granulomas, 

and not emaciated. A subsample of this population (n=26) was 

transported to the University of Maryland Aquatic Pathobiology Center, and eight fish were sacrificed upon arrival to 

determine the initial prevalence of mycobacterial infection. 

This initial prevalence was determined at 88% (95% confidence interval (C.I.) 47.3-99.7%). Fish were randomly distributed in 500-L experimental recirculating tanks (n = 6/tank). 

Water quality in each independent tank system was maintained 

through biofiltration. Dissolved oxygen (DO) was maintained 

at 7.0, 4.5, or 2.0 mg/L in each of the respective tanks using 

computer-controlled oxygen sensing and delivery systems. 

Fish were acclimated to experimental DO levels gradually, and 

reduced, but not significantly different from high ration controls (+306 Kcal and +330 Kcal respectively, p = 0.3375).

Red cell volume and plasma protein were reduced solely 

by low ration (p < 0.01), with mycobacteriosis having little 

influence (p > 0.05). Leukopenia was observed in inoculated 

fish receiving both diets, but was not noted in sham injected 

controls. Significant depression of white cell volume in 

HRM fish was apparent at 4 weeks (p = 0.02), but returned to 

baseline levels by 8 weeks (p = 0.77). In contrast, white cell 

volume continued to declined in LRM fish, becoming significantly different from that in low ration controls at 8 weeks 

(p = 0.018).

Our data suggest that food quantity can impact the severity and progression of mycobacteriosis in experimentally 

infected striped bass. Low energy intake resulted in a severe, 

chronic, systemic infection characterized by high bacterial 

loading and gradual reduction in total body energy, which 

commonly progressed to mortality. In contrast, adequate 

energy intake resulted in classic granulamatous inflammation 

of reduced severity primarily associated with mesenteric and 

haematopoetic tissues, substantially reduced bacterial replication, and similar total body energy as found in un-inoculated 

controls. While the application of these data to wild striped 

bass is only theoretical, the potential impact of nutritional and 

other environmental stressors warrants further attention.

Literature Cited

Gauthier, D.T., Rhodes, M.W., Vogelbein, W.K., Kator, H., 

and Ottinger, C.A., 2003, Experimental mycobacteriosis in 

striped bass (Morone saxatilis): Diseases of Aquatic Organisms, v. 54, p. 105-117.

20 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
maintained at those levels for 6 months. No deaths occurred 

throughout the holding period, except for one fish that jumped 

out of the 2.0-mg/L tank. At the end of the experiment, all fish 

were sacrificed and liver samples were cultured for mycobacteria. Only 2/6 (33%, 95% C.I. 4.3%-77.7%), 2/6 (33%, 95% 

C.I. 4.3%-77.7%) and 1/5 (20%, 95% C.I. 0.5%-71.6%) fish 

remained culture-positive for mycobacteria from the 7.0, 4.5, 

and 2.0 mg/L DO regimes, respectively. Although the number 

of mycobacterial CFUs were low from “culture-positive” fish, 

the lower prevalence at the end of the experiment (p=0.01, 

pooled prevalence 5/17, 29%, 95% C.I. 10.3%-56.0%) suggests that fish may be able to recover from an “infected” state 

to a healthy, “uninfected” state. Further, hypoxia alone, in the 

absence of any other water-quality stressors or confounding 

variables, does not appear to potentiate mycobacterial disease 

progression in hybrid striped bass.

The second study investigated the presence of mycobacteria in wild-captured fish collected using beach seines, cast 

nets, or bank traps from the Chicamacomico and Pocomoke 

Rivers of the Chesapeake Bay. Fish were transported live, 

immediately following capture, to the laboratory for necropsy. 

No externally visible lesions were present on any fish. Spleen 

tissue was aseptically sampled, homogenized in BPBS, and 

plated on Middlebrook 7H10 agar supplemented with Bacto 

Middlebrook OADC for mycobacterial growth. Mycobacteria 

were recovered from seven species of fish (Table 1). These 

data indicate that mycobacteria can infect multiple Chesapeake Bay fish species, in addition to striped bass and Atlantic 

menhaden.

Interpretation of results from these two studies emphasizes the importance of terminology in describing diagnostic test results and true infection or disease status. Simple 

recovery of very low CFUs (i.e., <102/g) of mycobacteria from 

an animal’s spleen suggests that the animal is indeed infected. 

However, low CFU data alone are likely insufficient to determine if an active infection is in progress. Infection represents 

a continuum from invasion, to phagocytosis, to bacterial 

multiplication in a tissue, to tissue injury and granuloma formation, and potentially, to overt disease (i.e., altered behavior, inappetence, petechial hemorrhage, fibrosis, adhesions, 

emaciation, severe granulomas, co-infection, etc.). Fish can 

also be variously classified as subclinical carriers or clinically 

diseased along this spectrum. These semantics are key because 

many reports of the prevalence of mycobacteria in fish populations do not differentiate between “carrier” status and “disease” status. This distinction is important since the impacts of 

infection and frank disease differ both for individual fish and 

for populations. Further, data from several studies in the literature (including the hypoxia study, above) indicate that fish can 

recover from clinical disease and/or can clear themselves of 

mycobacterial infections.

The notion of recovery is key because it indicates that, in 

the absence of continued infection pressure or stressors, fish 

may be able to heal themselves. Since it is impossible to eradicate mycobacteria from the Bay environment, it seems reasonable that management efforts need to focus on decreasing 

stressors that either foster mycobacterial infection in healthy 

fish, or lead to disease progression in subclinically infected 

(carrier) fish. Further, management should strive to reduce 

the constituents within the environmental media that foster 

growth of mycobacteria. Figure 1 provides an initial schematic 

representation of mycobacterial infection, disease progression, 

recovery, and the role of environmental stressors.

This conceptual framework provides a means for considering additional questions about the epidemiology of mycobacterial infections among fish. Are mycobacterial infections 

in Chesapeake Bay biota an emerging issue or have piscine 

infections gone mostly unnoticed due to the relatively challenging nature of mycobacterial culture, isolation, and identification? What is the biological relevance of prevalence based 

solely on detection of mycobacteria in the absence of clinical 

disease state? What factors may affect higher prevalence data 

in different river systems? Is the environmental state of the 

Bay such that we are poised to see large numbers of different 

organisms affected with disease in the presence of other, predisposing stress factors? Data presented at this workshop may 

help refocus attention and resources on the anthropogenically 

accelerated eutrophication of one of our most valuable natural 

Mycobacteriosis in Chesapeake Bay fishes: Perspectives and questions. 21

Table 1. Prevalence of isolation of mycobacteria from fishes from two Chesapeake Bay tributaries.

Species (n) Prevalence 95% CI

Blueback herring, Alosa aestivalis (17) 12% 1.5-36.4

Winter flounder, Pleuronectes americanus (26) 12% 2.5-30.2

Striped killifish, Fundulus majalis (1) 100% 2.5-100.0

Mummichog, Fundulus heteroclitus (3) 33% 0.8-90.6

Largemouth bass, Micropterus salmoides (1) 100% 2.5-100.0

Weakfish, Cynoscion regalis (2) 50% 1.3-98.7

Spot, Leiostomus xanthurus (27) 7% 0.9-24.3

White perch, Morone americana (87) 20% 11.8-29.4
resources, and discussion of these enriched estuarine waters as 

an environmental reservoir for mycobacteria.

Support for portions of these studies was provided by 

the Maryland Agriculture Experiment Station (MAES), the 

National Oceanic and Atmospheric Administration (NOAA), 

the Maryland Department of Health and Mental Hygiene, and 

the Centers for Disease Control and Prevention (CDC).

Initial investigation of the 

overall health and presence of 

mycobacteriosis in Roanoke River, NC, 

striped bass (Morone saxatilis).

Anthony S. Overton1, John M. Jacobs2, John W. 

Stiller3, and Eric B. May4

1

East Carolina University, Thomas Harriot College of Arts and Science, 

Department of Biology, Howell Science Complex, Greenville, NC 27858; 

email: OvertonA@ecu.edu. 2NOAA/NOS Cooperative Oxford Lab, 904 

South Morris Street, Oxford, MD 21654. 3East Carolina University, 

Thomas Harriot College of Arts and Science, Department of Biology, 

Howell Science Complex, Greenville, NC 27858. 4NOAA Living Marine 

Resources Cooperative Science Center, Department of Natural 

Sciences, University of Maryland Eastern Shore, Princess Anne, MD 

21653.

The prevalence of mycobacteriosis in Chesapeake Bay 

has received considerable attention. However, little information exists for striped bass from other regions of their Atlantic 

Coast range. To address this concern, we examined adult 

striped bass at Weldon and Jamesville on the Roanoke River, 

NC, during April of 2003.

Sixty striped bass were collected from the Roanoke River 

and ranged in size from 260 mm to 790 mm (total length). 

Weight, length, condition factor, relative mesenteric body fat, 

and gross observation of external and visceral lesions and 

parasite burden were conducted in the field. Sections of liver, 

spleen, and head kidney were both preserved in 10% NBF and 

frozen at -20 °C for routine paraffin histology and molecular 

detection and identification of Mycobacterium spp. Genetic 

probing of tissues was accomplished with Mycobacterium-specific PCR amplification of the 16s rRNA gene with amplification products sequenced and compared against previously 

reported Mycobacterium species sequences.

Sequences of the small subunit ribosomal RNA gene 

(16S rDNA) were obtained from all Mycobacterium species available, by database searches and from unpublished 

sequences provided by colleagues. We also retrieved 

sequences from a broad range of bacteria that might be present 

on striped bass, or in their habitats. Sequences were aligned 

using the computer program CLUSTAL W (Thompson et 

al., 1994) and adjusted by eye. We examined alignments for 

regions of sequence that were conserved in Mycobacterium

(the same sequence in all species within the genus), but different in other bacteria that might be present in mixed samples. 

We also assayed primer sequences designed previously by 

other researchers to amplify complete mycobacterial 16S 

rDNA sequences from environmental samples (Rhodes et al., 

2001). Total sequence diversity found among Mycobacterium, 

22 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

Figure 1. Schematic diagram showing mycobacterial disease 

progression and recovery in fish. The effects of environmental 

stress are shown to affect the state of the host. However, 

environmental conditions can also affect the density of 

mycobacteria in the reservoir.
along with the sequence similarity present in closely related 

bacteria, precluded the design of absolutely specific primers. 

In total, six primers were constructed and tested.

Males made up 68% of the sample and 32% were 

females. Low-level infestations of intestinal parasites were 

present in nearly 80% of the fish. All of the striped bass 

examined had visible fat deposits in the viscera with 95% 

having some traces of visceral fat or moderate accumulation of 

fat. Granulomas were present in 83% of the fish with the vast 

majority being of verminous origin. Acid-fast bacteria were 

detected within at least one organ in 18% of the striped bass 

with the highest percentage (8.3%) visualized in the spleen, 

followed by mesenteric tissues. Low numbers of granulomas 

containing acid-fast bacteria were detected in the heart, liver, 

and head kidney. Acid-fast bacteria were detected in multiple 

organs in only 5% of the fish examined. The observed granulomas containing acid-fast bacteria are consistent with mycobacteriosis but no Mycobacterium sp. were detected by PCR 

amplification. All sequences recovered were from members 

of the bacterial order Actinomycetales, family Corynebacterineae, to which the genus Mycobacterium belongs. The two 

most common sequences were from Corynebacterium sundsvallense and C. thomssenii, two closely related species first 

described in 1999. C. sundsvallense has been isolated only 

from human clinical samples, while C. thomssenii has also 

been isolated from an air sample. The discrepancy between 

the visual observation of granulomas containing acid-fast 

bacteria and PCR results must be addressed in future efforts. 

It is clear that other factors including contamination, low 

levels of Mycobacterium in the fish samples, a higher prevalence of Corynebacteria than Mycobacterium in the tissues, or 

differences in the DNA extraction efficiency for the species 

involved may have influenced our results. The observed 

granulomas containing acid-fast bacteria are consistent with 

mycobacteriosis. It should also be noted that Corynebacterium are not acid fast and have different morphology than 

Mycobacterium. We conclude that striped bass in the Roanoke 

River have been exposed to acid-fast bacteria, but presumptive 

mycobacteriosis in the population has not been confirmed by 

PCR or culture.

Literature Cited

Rhodes, M.W., Kator, Howard, Kotob, Shaban, van Berkum, 

Peter, Kaattari, Ilsa, Vogelbein, Wolfgang, Floyd, M.M., 

Butler, W.R., Quinn, F.D., Ottinger, Christopher, and Shotts, 

Emmett, 2001, A unique mycobacterium species isolated 

from an epizootic of striped bass (Morone saxatilis): Emerging Infectious Diseases, Dispatches, v. 7, p. 896-899.

Thompson, J.D., Higgins, D.G., and Gibson, T.J., 1994, 

Clustal W improving the sensitivity of progressive multiple 

sequence alignment through sequence weighting, positionspecific gap penalties and weight matrix choice: Nucleic 

Acids Research, v. 22, p. 4673-4680.

Mycobacterial infections in striped 

bass (Morone saxatilis) from 

Delaware Bay.

Christopher A. Ottinger1, J. Jed Brown2, Christine L. 

Densmore1, Cliff E. Starliper1, Vicki S. Blazer1, Holly 

S. Weyers3, Katherine A. Beauchamp1, Martha W. 

Rhodes4, Howard Kator4, David T. Gauthier4, and 

Wolfgang K. Vogelbein4

1

U.S. Geological Survey, Leetown Science Center, National Fish 

Health Research Laboratory, 11649 Leetown Road, Kearneysville, WV 

25430; email: cottinger@usgs.gov, cdensmore@usgs.gov, cstarliper@

usgs.gov, vblazer@usgs.gov, kbeauchamp@usgs.gov. 2U.S. Fish and 

Wildlife Service, Delaware River Fisheries Coordinator’s Office, 2610 

Whitehall Neck Road, Smyrna, DE 19977; email: Jed_Brown@fws.

gov.

 3U.S. Geological Survey, Water Resources Discipline, Dover Field 

Office, 1289 McD Drive, Dover, DE 19901; email: hsweyers@usgs.gov. 4

Department of Environmental and Aquatic Animal Health, Virginia 

Institute of Marine Science, College of William and Mary, P.O. Box 

1346, Gloucester Point, VA 23062; email: martha@vims.edu, kator@

vims.edu, gauthier@vims.edu, wolf@vims.edu.

Much of what is known of mycobacteriosis in wild 

striped bass from the mid-Atlantic region of the United States 

is based on our observations from Chesapeake Bay and its 

tributaries, where high infection prevalence and lesioned fish 

are frequently observed. Comparatively, the occurrence and 

severity of mycobacteriosis in striped bass from watersheds 

adjacent to Chesapeake Bay are relatively unknown. This 

study represents the first report on mycobacterial infection in 

striped bass harvested from two sites in Delaware Bay.

Eighty striped bass (Morone saxatilis) were obtained 

from Delaware Bay using commercial gill-nets located adjacent to Woodland Beach (39.333°N, 75.475°W; n = 70) and 

Bowers Beach (39.058°N, 75.397°W; n = 10) in December 

of 2003. Bowers Beach and Woodland Beach samples were 

obtained over an 8-day period on one and three sample dates, 

respectively. Nets were fished for approximately 24 h, and 

live striped bass were removed and transported to shore in a 

water tank fed by pumped surface water. Fish were euthanized 

with a lethal dose of an anesthetic agent, packed in ice, and 

transported to the USGS National Fish Health Laboratory 

(Leetown, WV) for further processing. At necropsy for each 

specimen, fish were examined for gross external and internal lesions as well as the presence of parasites; total lengths 

and eviscerated weights were determined to calculate condition factor (K); and tissue samples were collected. Portions 

of spleens were aseptically harvested for bacterial culture, 

and tissue specimens were collected in Z-fix preservative for 

histological examination. Tissue specimens for histological 

Initial investigation of the overall health and presence of mycobacteriosis in Roanoke River, NC. 23
and bacteriological analyses were processed routinely using 

methods previously described and utilized for similar studies 

with Chesapeake Bay striped bass populations. Spleen, liver, 

kidney, and gonad were evaluated histologically for lesions, 

including presence and severity of granulomatous inflammation; presence of acid-fast bacteria associated with splenic, 

hepatic, and renal granulomas; and presence of parasites. 

Homogenates of aseptically harvested spleen tissue were 

serially diluted and plated onto Middlebrook and Brain Heart 

Infusion agars for bacterial isolation and enumeration. Recovered acid-fast and non-acid-fast bacteria were further characterized biochemically. Statistical analyses of results were 

performed using analysis of variance (size, condition factor), 

Pearson chi-square and two-tailed Fisher exact test (bacterial 

and parasite infection intensities, granuloma occurrence). All 

statistical analyses were performed using SYSTAT 11 (SYSTAT Software, Inc., Point Richmond, CA). Statistical significance was designated as p < 0.05.

No differences were noted based on size or condition of 

the fish. The size distribution of the striped bass was relatively 

homogeneous with mean total lengths of about 600 mm in all 

samples. Mean condition factors exceeded 0.95 in all samples 

and were not significantly different among the samples. 

Pooled condition factors for mycobacterial infected (n = 14) 

and noninfected (n = 66) striped bass were also not significantly different. With the exception of rectal nodules associated with acanthocephalan infections, no gross abnormalities 

were observed either externally or internally among these 

striped bass. The percentage of fish with coelomic nematode 

infections ranged from 26.6 – 69.2% and did not differ significantly among sample collections. The percentage of striped 

bass with rectal acanthocephalan infections was significantly 

different among samples, such that collections made at both 

sites on 12/09/03 and 12/10/03 (61.5 - 70.0%) were significantly higher than the Woodland Beach sample collected on 

12/17/03 (21.4%) but were not significantly different from 

each other. No significant differences in granuloma prevalence were observed among samples. Prevalence of acid-fast 

bacilli observed in association with splenic granulomas was 

low overall (6.25%, n = 80), and acid-fast bacilli were not 

observed in association with any liver or kidney granulomas. 

The occurrence of encysted helminthes in spleens was a 

common observation, but parasites were very seldom noted 

in association with granulomas in the liver, kidney, or gonad. 

Significant differences in mycobacterial infection prevalence 

(as determined by the combination of bacterial culture and 

histopathology) were observed among samples, with those 

obtained at Woodland Beach on 12/10/03 (53.8%, n = 13) 

and 12/17/03 (7.1%, n = 42) exhibiting the most striking 

differences. Mycobacterial infection intensities ranged from 

about 102 to 107 CFU g-1 spleen. Ten acid-fast isolates were 

obtained from the Delaware Bay striped bass in all, and only 

one presumptive Mycobacterium sp. was isolated from each 

positive sample. Seven of the ten acid-fast isolates were characterized by biochemical phenotyping. Only one of the seven 

Mycobacterium isolates, identified as M. chelonae, exactly fit 

existing species descriptions. Non-acid-fast bacterial infection 

prevalence was also significantly different among the samples. 

Infection intensities ranged from 103 to 105 CFU g-1 spleen. 

Lactococcus lactis ssp. lactis, and Pseudomonas fluorescens

were the most frequently identified non-acid-fast species.

Mycobacterial infection prevalences observed in the 

Delaware Bay samples were substantially lower than that 

reported for striped bass in Chesapeake Bay. In general, the 

infection intensities in these Delaware Bay striped bass were 

also lower than those previously reported for mycobacteria 

culture-positive striped bass of similar size from Chesapeake 

Bay. Although overall condition of these striped bass among 

the four Delaware Bay samples was rather homogeneous, differences in mycobacterial infection prevalence, non-acid-fast 

bacterial infection prevalence, and acanthocephalan infection 

prevalence were apparent. Differences in microbial exposures, 

diet, contact with environmental stressors, or genetic background might explain the intersample variation in bacterial and 

parasitic infections observed among these fish.

24  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Tag-recapture data from Chesapeake 

Bay striped bass indicate that natural 

mortality has increased.

Desmond M. Kahn1 and Victor Crecco2

1

Delaware Division of Fish and Wildlife, P.O. Box 330, Little Creek, 

DE 19961; email: desmond.kahn@state.de.us; 302-739-4782 x19. 2

Connecticut Division of Marine Fisheries, 333 Ferry Rd., Old Lyme, CT 

06371; email: vic.crecco@po.state.ct.us; 860-434-6043.

Coast-wide tagging studies of striped bass have been 

conducted annually since 1987 to determine trends in fishing 

mortality (F) rates. Annual tag-recovery studies have been 

performed during spring in all producer areas (Chesapeake 

Bay, Hudson River, and Delaware River), as well as during 

spring and fall along the coast from North Carolina to Massachusetts. Atlantic Coast striped bass are highly migratory 

and larger (> 75 cm TL) stripers tagged initially in Chesapeake 

Bay are often recovered coast-wide from North Carolina to 

New England. The U.S. Fish and Wildlife Service’s Annapolis Office has managed the tagging database and the Atlantic 

States Marine Fisheries Commission’s Striped Bass Tagging 

Subcommittee has analyzed the data with a standard protocol.

Until recently, stock assessment methods such as Virtual 

Population Analysis (VPA) and tag-based models on striped 

bass have assumed that natural mortality of all sizes of striped 

bass are constant (M = 0.15) over time. Under the constant M 

assumption, fishing mortality (F) estimates on striped bass can 

easily be derived by subtracting a constant M of 0.15 from the 

total mortality (Z) rate. Although the constant M assumption 

has been used almost universally in most finfish stock assessments, there is a growing body of evidence in the fisheries 

literature that natural mortality among most finfishes may vary 

systematically over time due to changes in biotic and abiotic 

factors, and may be also under the influence of density-dependent factors. Determining whether or not M is constant for 

striped bass is particularly important to test the hypothesis 

that the recent mycobacteriosis outbreak on striped bass in 

Chesapeake Bay after 1995 may have been linked to a recent 

rise in M.

In this study, we used the Baranov catch equation to 

estimate fishing (F) and natural mortality (M) independently 

for Chesapeake Bay stripers based on a time series (1987-

2004) of tag-recovery data. In the first step of this approach, 

tag-recovery data were used to estimate a time series of annual 

harvest (u) and total mortality (Z) rates for 18 in.+ and 28 in.+ 

striped bass from the Bay and elsewhere. We then substituted 

the annual u and Z estimates into the Baranov catch equation from which a time series of fishing (F) mortality rates 

was derived. Given total (Z) and fishing mortality (F), natural 

mortality (M) estimates were then derived from 1987 to 2004 

by subtracting F from Z. This catch equation approach has 

allowed us to specifically test the hypotheses that M is constant at 0.15 for striped bass in Chesapeake Bay and elsewhere 

from 1987 to 2004. Moreover, the time series of M estimates 

from Chesapeake Bay stripers allowed us to test the hypotheses of a causal linkage between the documented mycobacteria 

outbreak on Chesapeake Bay stripers after 1995 and a rise in 

striped bass mortality.

Our results indicated that tag-based total mortality (Z) 

estimates on smaller (> 18 in.) in upper Chesapeake Bay have 

risen steadily since 1995, but fishing mortality (F) from the 

catch equation approach remained steady at about 0.25 from 

1995 to 1999, then dropped steadily thereafter from 2000 to 

2004. As a result, natural mortality (M) estimates on smaller 

stripers from the upper Chesapeake Bay rose from 0.13 in 

1995 to peak levels (M = 0.47) in 2001. The M estimates 

after 2001 have dropped slightly (M range: 0.38-0.43) but 

were much higher in magnitude than M estimates prior to 

1997. Moreover, M estimates on smaller (18 in.+) striped bass 

from the Rappahanock River, Virginia, also rose even more 

abruptly, from about 0.12 in 1993 to peak levels of 0.73 in 

1999. Unlike the trend in M for upper Bay stripers, the M estimates on Virginia stripers fell abruptly after 2001 to pre-1997 

levels. The trends in M for Maryland and Virginia stripers 

exhibited a significant positive correlation. The timing of the 

increase in M throughout Chesapeake Bay coincided with 

the reported outbreak of mycobacteriosis, thereby supporting 

the hypothesis that mycobacteriosis caused enhanced natural 

mortality of resident striped bass in Chesapeake Bay.

 Although M estimates on resident striped bass in 

Chesapeake Bay fell after 2001, natural mortality levels for 

Maryland migratory striped bass (28 in.+) increased from 0.10 

in 1997 to 0.39 in 2004. This systematic increase in M is also 

in accord with the hypothesis that links the mycobacteriosis 

outbreak with a rise in M for migratory striped bass from 

upper Chesapeake Bay. The Virginia results for 28 in.+ fish, 

however, do not show a consistent increase in natural mortality (M) from 1997 to 2004. To pursue the mycobacteriosis 

hypothesis, one possible explanation for an increase and then 

a decline in natural mortality levels, which occurred independently in both Maryland and Virginia, is that more susceptible 

striped bass died due to the disease whereas the remaining fish 

may be more resistant.

 Finally, we used the Striped Bass Harvest Control Model 

(HCM) to determine whether or not the recent rise in resident 

striped bass recreational catches (harvested and released) and 

landings (harvested) during fall (Sept.-Oct.) from Maryland 

was consistent with a rise in natural mortality. The observed 

recreational catch and harvest data from 1984 to 2004 were 

based on the MRFSS survey. The observed fall recreational 

catches of striped bass in Maryland have remained persistently high from 1997 to 2004, but the fall harvest levels have 

fallen steadily from peak levels in 1996. We used the HCM to 

simulate the recreational catches and landings data from 1984 

to 2004 under the assumption of a rise in natural mortality (M) 

Tag-recapture data from Chesapeake Bay striped bass indicate that natural mortality has increased. 25
of resident striped bass. The model output (simulated catches 

and harvest) in the HCM was expressed as year (1984-2004) 

and age (ages 1-9) effects. Input parameters in the HCM 

include growth parameters in length (mm) and weight (kg) 

by age, percentage maturity by age, natural mortality (M) by 

year according to our M estimates from tagging and recruitment (age 0) by year-class based on the Maryland juvenile 

index. We assumed that the simulated recreational catches 

were composed of ages 1+ stripers, whereas the landings were 

composed of ages 3+ striped bass using a partial recruitment 

vector that was consistent with the current 18.0-in. minimum 

size limit. The HCM output would support the hypothesis of 

a rise in M if the trends in simulated fall recreational catches 

and harvest from 1995 to 2004 were similar to the trends in 

observed fall recreational data. Results from the HCM indicated that the simulated fall catches and landings from 1995 

to 2004 under a simulated rise in M were very similar to the 

trends in the observed fall recreational catches and harvest. 

These findings suggest that a rise in natural mortality since 

1996 has apparently reduced the number of legal-size (18 in.+) 

stripers in the recreational harvest after 1997. However, the 

attrition effects of enhanced natural mortality are less likely to 

be manifested on younger (ages 1-3) stripers, thereby leading to more stable fall catches of ages 1+ stripers in Maryland 

from 1996 to 2004. These findings are consistent with our 

stated hypothesis that M on resident striped bass has risen 

systematically since 1995. The model results did indicate, 

however, that the HCM could reproduce a similar trend in fall 

recreational catches and harvest under a constant M if either 

striped bass somatic growth declined systematically after 

1995, or if striped bass migration rates from the Bay to the 

Coast accelerated after 1995.

Epizootic mycobacteriosis in 

Chesapeake Bay striped bass: 

What is the fate of infected fish?

Wolfgang K. Vogelbein1, John M. Hoenig2, and David 

T. Gauthier1

1

Department of Environmental and Aquatic Animal Health and 

2

Department of Fisheries Science, Virginia Institute of Marine Science, 

The College of William and Mary, 1208 Greate Rd., Gloucester Point, VA 

23062; email: wolf@vims.edu.

Striped bass (Morone saxatilis) in Chesapeake Bay, 

USA, are currently experiencing an epizootic of mycobacteriosis. Visceral disease prevalence in resident fish exceeds 

50% and prevalence of skin ulcers can exceed 30% in some 

areas. Two primary hypotheses regarding emergence of this 

chronic bacterial disease propose that anthropogenic stressors constitute important underlying modulating factors. The 

first suggests that elevated nutrient inputs to the Bay and the 

associated eutrophication results in loss of summer thermal 

refugia for striped bass, forcing the fish into sub-optimal and 

stressful habitat during the warm summer months. The second 

hypothesis proposes alterations in trophic structure and starvation as a result of over-harvesting of key prey species such as 

Atlantic menhaden (Brevoortia tyrannus) and reductions in 

the food forage base. Ongoing striped bass tagging programs 

in Maryland and Virginia indicate a significant increase in 

non-fishing (natural) mortality in recent years. The contribution of mycobacteriosis to this increased mortality and which, 

if any, environmental factors modulate disease expression in 

Chesapeake Bay remain unclear. The high disease prevalence 

and concurrent increase in natural mortality of striped bass in 

recent years are of great concern to environmental scientists, 

fisheries managers, and anglers. A critical question regarding striped bass mycobacteriosis pertains to potential adverse 

impacts of the disease at the population level. Does the disease 

cause mortality in striped bass and will it have a long-term 

detrimental effect on the Atlantic Coastal migratory stock?

During 2005 we initiated field studies to determine 

whether mycobacteriosis is a cause of significant mortality in 

striped bass. The objectives of this study were to determine 

the rate of progression/regression of dermal disease by holding 

striped bass under field conditions (caging studies) to determine the relative mortality of fish with and without visible 

skin lesions, and to develop and apply a statistical model to 

estimate relative survival in fish with and without visceral 

disease as predicted by the presence of skin lesions (tagging 

studies). To accomplish this we made use of an existing annual 

striped bass tagging program at Virginia Institute of Marine 

26 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
Science and initiated short-term field caging studies in the 

Rappahannock River, Virginia.

During fall 2005 we photographed (to document fish 

health status), tagged, and released a total of 1,811 striped 

bass belonging to two groups, fish that exhibited skin lesions 

characteristic of mycobacteriosis and fish without them. 

The rationale for this approach was that if the disease causes 

mortality, then tag returns from the group of fish exhibiting 

disease signs should be lower than returns from the group 

without signs of the disease. This study is ongoing and another 

large group of fish with and without external clinical signs 

will be tagged during 2006. The fraction of tags returned from 

each group will then be used to estimate relative survival 

(i.e., impact of the disease). We have established and widely 

publicized a tag return reward program in collaboration with 

the Virginia Marine Resources Commission (VMRC) that will 

motivate commercial and recreational anglers to return whole 

tagged fish to us on ice. We offer a $20 reward for the return 

of a whole fish tagged with a special fluorescent green internal 

anchor tag and $5 for return of the tag only. Additionally, 

VMRC has issued an exemption in effect from 2005 - 2008 for 

all striped bass with the green streamer tag. Tagged fish will 

not count against daily creel limits or tag quotas and fish size 

and seasonal restrictions will not apply to these fish. Because 

we photo-document health status of all fish prior to tagging and release, this program should also provide important 

information on skin lesion progression or regression/healing 

over the course of the study. As of April 2006, we have had 

~120 tag returns (~6.6% tag return rate), many of which were 

returned to us as whole fish. Most of these returns were shortterm recaptures by commercial pound net fishermen working 

in the mouth of the Rappahannock River.

We have held fish with and without skin lesions in two 

large net pens deployed in the upper Rappahannock River 

(near Tappahannock, VA) during fall 2005. This study was 

conducted in order to observe short-term temporal aspects of 

disease prevalence, severity, survival rates, and progression/

healing. Weather conditions were unusual during this time 

period, with water temperatures remaining high (>20 oC) very 

late into the season, followed by a rapid dropoff of temperatures to <10 oC. The optimal temperature range for striped bass 

lies between these two values; therefore, we were not able 

to keep striped bass in the pen enclosures for the amount of 

time that we anticipated. We were, however, able to maintain 

some fish in the pen for up to 10 wk. Histological analysis of 

these fish is in progress. Changes in skin lesion appearance 

were subtle or absent in penned fish over the course of the 

study, suggesting that these changes occur over relatively long 

periods of time. We plan to repeat this study during fall 2006. 

As striped bass are stressed at very low salinities such as those 

observed in the upper reaches where we deployed the net pens 

in 2005, we plan to move them to the mouth of the Rappahannock River in 2006 to take advantage of the higher salinity 

regime.

Estimation of relative mortality between diseased/nondiseased animals via tag-recapture studies requires non-lethal 

diagnostic methods for determination of disease/exposure 

state. A serologic test of disease status would be ideal, as a 

small sample of blood could be collected prior to fish tagging and release. However, such a non-lethal diagnostic is 

not yet available for mycobacteriosis in striped bass. We have 

therefore focused efforts on better characterization and detection of what we believe to be the very earliest and most subtle 

skin pathologies associated with mycobacteriosis in the striped 

bass. Based on extensive histological verification, we consider 

these lesions to be pathognomonic (specific) for the disease 

and feel that their prevalence has been significantly underestimated in prior studies. We believe this to be one of the 

reasons for the large disparity between skin (30%) and visceral 

(50-70%) disease prevalence. Better tracking of these early 

skin lesions will provide us with higher concordance between 

the dermal and visceral disease states and will allow use of 

skin pathology as an indicator of overall disease state in lieu 

of a non-lethal serologic test. This work was funded in part by 

the Virginia Marine Resources Commission and Virginia Sea 

Grant Program.

Epizootic mycobacteriosis in Chesapeake Bay striped bass: What is the fate of infected fish? 27
28  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

Perspective of Resource Managers

Facilitator

Frank Panek – U.S. Geological Survey, Leetown Science Center

Resource managers were asked to provide an opening statement in which they were to summarize their respective agency’s perspective on 

mycobacteriosis in striped bass and to offer comments on issues of concern to them as a resource management agency within the Chesapeake 

Bay system. These initial agency comments were to provide a forum for questions and discussions by the workshop participants on how the 

research community could help address the informational needs of the resource managers. To capture these discussions for the record, staff 

members from the Chesapeake Research Consortium served as recorders. The following summaries reflect the initial comments made by the 

managers and the questions and discussions that followed.

Steve Giordano

NOAA, NMFS, Chesapeake Bay Office

Statement: In the past, NOAA managed fisheries based on individual species and small spatial scale. Ecosystem-based fisheries management has replaced the single-species approach with multiple fish species managed as a group. This is an adaptive 

ecosystem approach to management that includes integrated fisheries assessments, product syntheses, modeling, and analysis. 

NOAA is responsible for developing the new Ecosystem Based Fisheries Management Plan for Chesapeake Bay and provides 

Federal support for State management authorities through the NOAA Chesapeake Bay Office (NCBO). The NCBO coordinates 

and facilitates NOAA efforts in Chesapeake Bay and acts as a liaison to NOAA headquarters and other offices nationwide. 

In general, information most likely to meet NOAA’s needs would be based on data that can support the adaptive ecosystem 

management process. The National Marine Fisheries Service needs information on the current epizootic of mycobacteriosis in 

striped bass of Chesapeake Bay and elsewhere to evaluate the possible implications for the management of the striped bass stock 

in the Economic Exclusion Zone (EEZ).

Comments, Questions, and Answers by Workshop Participants:

Comment – Striped bass are protected and it’s not good to sample the spawning stock.

Question – Is there going to be any enforcement in the EEZ? – There will be some limits and regulations on size, age, 

etc. – how will they be enforced?

Response – The public comment period for opening the EEZ to striped bass fishing continues to May 24, 2006. This is 

a good opportunity for asking questions and expressing concerns on the opening of the EEZ. When the EEZ is open, 

the landing laws of individual states (bag limits, size, etc.) will be enforced at the ports. States will have the regulatory 

role – not the Federal government.

Nancy Butowski

Maryland Department of Natural Resources (MD DNR) 

Statement: The MD DNR Fisheries Service is most interested in answers to the following questions: How many fish are dying 

from this disease? What is the nutritional status of striped bass? Are environmental factors such as excess nutrients and pollution impacting the disease? What are the human health impacts and what steps should be taken to keep humans safe? What are 

the important research questions that MD DNR should promote and fund? What message do we need to get across to the public 

about the presence of disease and how it affects the Chesapeake Bay?

The information on how many striped bass are dying from the disease will improve our ability to calculate the natural mortality 

rate for stock assessments on striped bass. The nutritional status of striped bass is in question regarding whether the disease leads 

to poor body condition or whether poor body condition is the result of a decrease in the availability of forage fish, especially 

Atlantic menhaden. If there are environmental factors affecting the impact of disease, then we need to identify the factors and 

take steps to mitigate their effects. We need the best scientific information available on the disease including a priority list of 
Perspective of Resource Managers 29

continued research and monitoring requirements. We need to make sure that any human safety issues are addressed and give a 

clear message to the public.

Comments, Questions, and Answers:

Question – What would be the limitations on MD DNR to participate in this integrated work? Are there political 

boundaries?

Response – Work should be done from a Bay-wide perspective. As we develop ecosystem-based management goals 

and objectives for the striped bass resource, a Bay-wide perspective is necessary. There are a lot of partners involved 

in many aspects of the Bay from land management to protecting aquatic resources. It is important to have a clear 

understanding of everyone’s role. During this time of limited funding and manpower we want to ensure that our 

efforts are not redundant. Keeping all of the partners involved in the process is necessary for an integrated approach. 

We are just developing the practical steps in implementing ecosystem based fisheries management (EBFM) and we 

need to inform people about the concept and what it means. Many people don’t understand what EBFM is all about. 

An ecosystem-based fishery management plan (EBFMP) will help integrate the partners. It will provide a good “road 

map” to get everyone on the same page and keep them on track towards accomplishing Bay-wide goals and objectives. It will provide a forum for discussing ecosystem modeling efforts and help identify factors we should consider. 

Disease issues have not been well integrated into a Bay-wide approach. It seems like disease considerations have been 

somewhat of a separate endeavor. The occurrence and prevalence of disease should be examined as part of the overall 

health of the Bay. Many times disease research results have not reached the managers. Since fish health has not always 

been integrated into past management approaches, adopting an EBFM approach will be an important improvement. 

We have to keep in mind that research targets will not always answer the questions so we need to add monitoring to 

these efforts to get the full picture. People care about the fishing industry and the health of fish. We need to reach out 

to the economic industry or tourism and make a good connection. 

Question – What message does DNR want to give the public?

Response – We need to provide the most accurate picture about the health of the fish in the Bay and provide a very 

straightforward approach to the public. There is a lot of incorrect information that appears in the newspapers. We need 

to be timely with what we tell the public and tell them what we do and don’t know. We need good public relations but 

mostly we need to stick to the facts. As a group, we need to establish an internal pathway to share information. People want to know if fish are safe to eat and how to handle them. Is the Bay less or more healthy, etc.?

Question – How do we package stories for the media?

Response – We need to be factual and upbeat to get the public’s attention. 

Question – Should we be proactive in our media approach?

Response – It is always good to do this but the chances are that the information will not get into the newspapers. However, we have to try to keep on top of the issues.

Lewis Gillingham

Virginia Marine Resources Commission (VMRC)

Statement: VMRC is a regulatory agency and has about 200 employees. Field personnel include 3 individuals involved in stock 

assessment and 70 law enforcement officers. VMRC relies on the Virginia Institute of Marine Science and other institutions to 

provide research. VMRC does not directly monitor fish disease. Sister agencies play an active role in monitoring water quality, 

harmful contaminants in finfish, and bacterial levels in shellfish. Virginia Department of Environmental Quality (DEQ) operates a monthly monitoring program that measures contaminants in finfish. Virginia DEQ issues consumption advisories when 

contaminant levels exceed expectable norms. This department also monitors water quality at beaches and will issue advisories 

or close beaches as appropriate. The Virginia Department of Shellfish Sanitation monitors oysters, clams, and other shellfish primarily for bacterial contamination using water-quality measures over the shellfish beds as an indicator. This department closes 

beds to harvest when bacterial levels exceed acceptable levels.
30 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

The most important issue to VMRC is how mycobacteriosis impacts striped bass mortality rates and at what age the fish die. 

VMRC needs to know how the mycobacteriosis epizootic may be impacting stock assessment. VMRC is interested in the health 

issues surrounding this disease in order to address public concerns regarding the health of the striped bass and the percentage of 

fish that are impacted by this disease.

Comments, Questions, and Answers:

Question – Maryland has an agency to monitor the health of striped bass but Virginia doesn’t. How can we get more 

information from Virginia waters? Is CHESMMAP a VMRC project?

Response – CHESMMAP started out as a NOAA-funded project. It is now supported through a combination of Federal and State funds. CHESMMAP is a good example of a multiple species monitoring effort. Hopefully, CBPO will 

have a monitoring program where there will be a clearinghouse for tools, models, and research. There are some funds 

available in Virginia to support striped bass research. Research funds are available from the Virginia Saltwater Recreational Fishing Development Fund. Money for this fund comes for the sale of saltwater fishing licenses. Each year 1.2 

to 1.5 million dollars for projects is available with some funds committed to ongoing projects.
Prioritized Research Needs  31

Prioritized Research Needs

Facilitators

Fred Kern – NOAA/NOS Oxford Cooperative Laboratory and

Frank M. Panek – USGS, Leetown Science Center

Attendees were split into two groups to discuss prioritization of research needs based on knowledge gaps identified in the State of Knowledge session. Participants in each 

group were asked to rank the previously identified knowledge 

gaps based on importance to understanding the overall issues 

pertaining to mycobacteriosis in striped bass with an emphasis 

on the information needs presented by the resource managers. 

The rankings were synthesized in a joint session immediately 

following the concurrent breakout sessions.

In the prioritization of research needs, it was recognized 

that beyond specific research projects, there are overarching 

themes that need to be considered, as well as mechanisms 

for enhancing the utility of information gathered by various 

research groups. These overarching themes include standardized approaches and unified databases (research integration) 

and socioeconomic considerations. See Appendix 2 for graphic 

presentation of this information and its preferred timetable for 

implementation.

Standardized Approaches and Unified 

Databases (Research Integration)

Continued Development of Diagnostic Tools: In discussions of knowledge gaps, the need for rapid tools for 

identification and quantification of mycobacteria to the 

species level was perceived as critical for future efforts. 

Current bacterial culture-based methods are time consuming, prone to contamination, and somewhat limited in 

application. Biomolecular tools hold much promise for 

expanding the scope of current efforts, and are currently 

being pursued by research institutions. Method development was perceived as an ongoing process with technological advancements, and thus an extremely important 

overarching need for the study of mycobacteriosis and 

mycobacterial ecology.

Standardized Monitoring and Assessment Methodologies: Field monitoring efforts are conducted by several 

academic institutions and State and Federal agencies 

within the Bay. Sampling strategies and disease status 

assessment methodologies vary among these groups, making data collected difficult to compare. It was recognized 

that both coordinated sampling efforts and standardized 

1.

2.

methods would allow for more efficient sampling and better data compatibility.

Centralized Data Management: Standardization of 

monitoring and assessment methodologies is the key 

to the development of centralized data management. 

Resource managers in particular felt this would allow for 

the application of new approaches to large data sets which 

may lead to increased understanding of the dynamics of 

this disease in striped bass.

Socioeconomic Considerations

Economic Impacts on the Fishery and Related Industries: Striped bass is a commodity supporting significant 

industries for recreational and commercial fisheries within 

Chesapeake Bay. It was recognized by the workshop 

participants that addressing the impact of mycobacteriosis on both the recreational and commercial harvest was 

important. While there is no direct evidence of acute or 

chronic mortality on striped bass in the Bay resulting 

from infection, the presence of external lesions on fish 

may have effects on both of these fisheries. The effects of 

public perceptions of this fish disease on commerce must 

be considered. Socioeconomic data should be integrated 

into outreach programs aimed at the fishing public.

Public Health Outreach: The group recognized that the 

potential exists for transmission of certain mycobacterial 

species from fish to humans. Therefore, increased coordination of findings with public health departments and 

outreach are an overarching concern.

Specific Research Needs

In the prioritization of research needs, general categories were identified and ranked in order of priority. Specific 

research questions contributed by the group are ranked in 

order of priority within the timeframe in which results may be 

expected. Those categorized as short term reflect the potential 

for the question to be addressed within 2 years, while longterm questions may require 5 or more years of research efforts 

3.

1.

2.
32 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

before answers can be derived. See Appendix 2 for graphic 

presentation of this information. The specific research needs 

within each of these prioritized areas are not listed in any 

particular order.

Population Level Impacts/Distribution: Considerable 

attention was focused on the issue of mortality associated 

with mycobacteriosis in striped bass, and gaining a better 

understanding of the distribution of disease. Several questions were raised by the workshop participants concerning 

the information needs from ongoing research.

An ongoing project is addressing the potential association between mycobacteriosis and natural mortality in 

striped bass. Additional studies are evaluating the possible increase in natural mortality without reference to 

specific etiologies. Ongoing studies are also examining 

spatial, temporal, and age- and sex-specific differences in 

mycobacteriosis prevalence in the resident Chesapeake 

stocks and coastal migratory stock. These types of studies 

need to be expanded to better define the impacts, distribution, and prevalence of mycobacteriosis in striped bass 

outside Chesapeake Bay and thus determine if the Bay is 

the epicenter for this disease. Consideration also needs to 

be given on how this type of data could be included in the 

development of multi-species population dynamics and 

ecosystem models.

Questions involving the sub-lethal effects of mycobacteriosis on striped bass immune function, reproduction, and 

other physiologic capabilities could be addressed in shortterm projects. So, too, could the examination of existing 

data sets for density-dependent effects associated with 

particularly strong year classes and seasonal differences 

in disease prevalence, presentation, and severity. Longterm research questions include determining if striped 

bass develop immunity to mycobacterial infections and if 

infections influence striped bass migration patterns within 

the Chesapeake and along the Atlantic Coast.

Mycobacterial Ecology/Routes of Exposure: Highlighted among group discussion was the lack of information on the ecology of environmental mycobacteria. 

Almost nothing is known about the distribution of mycobacteria outside their piscine hosts. There is also very 

little known about how the bacteria are transmitted to fish.

1.

2.

Ongoing research includes the development of rapid, 

sensitive, and specific quantitative tools for environmental 

mycobacterial community assessment. Additional ongoing 

research is examining the potential for vertical transmission of mycobacterial infections, the prevalence and distribution of mycobacterial infections within striped bass 

prey items and parasites, and the relative role of different 

mycobacterial isolates in causing disease in striped bass.

Questions involving the possible role of environmental 

factors (pH, salinity, temperature, etc.) on the growth 

of the relevant mycobacteria could be completed in the 

short term. So, too, could investigations of other forms 

of mycobacterial transmission including water-borne, 

ingestion, trauma, and vectors. A long-term effort will 

be required to address issues such as the environmental 

distribution of the Mycobacterium spp. impacting Chesapeake Bay striped bass, identifying the environmental 

factors that influence mycobacteria distribution, and the 

evaluation of possible mycobacteria strain-based virulence differences relative to health risks to striped bass 

and humans.

Impacts of Environmental Stressors: Epizootics of 

disease are often the result of complex interactions among 

the host, the pathogen, and the environment. Two leading hypotheses have surfaced concerning the issue of 

environmental stressors. One questions the influence of 

water quality (temperature, hypoxia, eutrophication) on 

host susceptibility and disease progression. The second 

questions the influence of shifts in striped bass diet and 

prey availability. Some work has been completed or is 

ongoing in these areas, but much research remains. Additional short-term research should address the influence 

of environmental stressors on susceptibility and progression of disease associated with various species/strains of 

mycobacteria. Identifying genetic factors within the host 

that make them more susceptible to these pathogens or 

stressors was also identified as a research need. As little is 

known in this area, detailed answers would likely require 

a long-term research commitment.

3.
Research Integration and Role of Federal Agencies  33

Research Integration and Role of Federal Agencies

Facilitators

Kevin Sellner - Chesapeake Research Consortium and 

Frank Panek - USGS, Leetown Science Center

The following issues were addressed by workshop 

participants.

How can monitoring and assessment surveys become 

a shared resource for mycobacteriosis researchers in 

the Bay watershed and be made more cost effective in 

approach?

Two critical factors were identified relative to this question, standardized methodologies and centralized data 

management. The Chesapeake Bay Consortium recently 

held a joint workshop with NOAA Chesapeake Bay 

Office on fish stock assessment in the Bay. This workshop 

recognized that the difference in the type of data collected, collection methods, and data accessibility between 

states and agencies makes data integration difficult, if not 

impossible. State and Federal funding levels are decreasing, so it is more important than ever that some kind of 

shared resource for these data be developed. The proceedings from this workshop include recommendations 

for such integration. For instance, coordinated trawling 

programs for the mainstem Bay and its tributaries could 

benefit several State and Federal programs. The basic 

issues described in the stock assessment workshop are 

nearly identical to those faced by those involved with 

mycobacteriosis in striped bass. The need and justification 

for standardized methodologies are identical and seem to 

be a logical, overriding priority.

The participants recognized that research redundancies 

have existed in the past and that with limited resources; 

these redundancies diminish our collective abilities to 

meet science and management objectives. In order to 

address this problem we need to define what can be done 

to improve communication. As a first step in this direction, the workshop participants made several recommendations for centralized data management and communications. A clearinghouse for compilation of ongoing 

research projects is clearly needed. The National Institutes 

of Health Center of Excellence Program is an example 

of a web site for collecting resource data in a format that 

is user-friendly to the scientists and managers. It was 

suggested that an annual meeting of a steering committee, with a written statement of purpose, a publication, 

methodology guidelines, and a web site is a direction that 

the group should consider for the future. Establishing a 

1.

2.

Consortium on Aquatic Animal Health issues might be a 

possibility. This could potentially be a Chesapeake Bay 

Program workgroup under the Living Resources Subcommittee that reports to the Resource Assessment Work 

Group on stress indicators. Having a person on the standing committee of the Atlantic States Marine Fisheries 

Commission to address the aquatic animal health issues 

in the Bay and mid-Atlantic region might also provide 

the needed coordination. The Annual Eastern Fish Health 

Workshop (EFHW) may be another potential venue for 

an annual meeting (cosponsored by USGS and NOAA 

Oxford) on mycobacteriosis in Chesapeake Bay striped 

bass. Many of the workshop participants regularly attend 

the EFHW.

Other web-based applications were also discussed by the 

participants. A website addressing outreach already exists 

and can be found at http://wwww.MyBay.umd.edu. This 

website is modeled after the Sea Grant data-rich resource 

for academia and agencies. It might be possible to dedicate a page within this web site to aquatic animal health 

and link to other resources of interest to Bay researchers 

and managers. A list-serve for sharing emails among colleagues was also suggested and could also be located on 

the web site. A participant list with contact information 

published with the proceedings from this workshop would 

be a first and very simple step to foster improved communications.

Given that mycobacterial infections in striped bass is an 

emerging issue in the Bay and that priorities are shifting 

in conjunction with declining budgets, where should we 

look for new or alternative sources of funding? The list 

of potential funding sources identified during this session 

were as follows: National Science Foundation Disease 

Program (primary focus on modeling); Virginia Saltwater Recreational Fishing Development Fund; National 

Institute for Environmental Health; Virginia Environmental Endowment (private funding); NOAA Living Marine 

Resources Program; U.S. Environmental Protection 

Agency STAR grants; U.S. Department of Agriculture 

Aquaculture funding through ARS (disease/pathogenesis 

research); Allied Signals; Coastal America (USGS and 

NOAA as partners); and NOAA CBSAC – Integrated 

Research Program.

3.
34  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

Appendixes

Appendix 1: Workshop Agenda ........................................................................................................35

Appendix 2: Prioritized Research Agenda with Estimated Timelines for Completion .............37

Appendix 3: Participant List ..............................................................................................................38
Appendixes  35

Appendix 1: Workshop Agenda.—Continued

Day 1: Tuesday, May 9, 2006

0630 – 0745 Breakfast

0800 – 0815 Opening Remarks and Introductions (Bob Wood – NOAA/NOS Cooperative Oxford Laboratory, Frank Panek - USGS, Leetown Science Center, Chris Ottinger - USGS, Leetown Science Center, John Jacobs – NOAA/NOS Cooperative Oxford 

Laboratory)

Moderator: Bob Wood (NOAA/NOS Cooperative Oxford Laboratory) 

0815 – 0845 Eric B. May (University of Maryland) - A historical perspective on diseases of striped bass with emphasis on mycobacteriosis.

0845 – 0915 Howard Kator (Virginia Institute of Marine Science) - The ecology of mycobacteria infecting striped bass (Morone saxatilis) 

in Chesapeake Bay: A research plan.

0915 – 0945 Frank M. Panek (USGS, Leetown Science Center) - Striped bass mycobacteriosis: A zoonotic disease of concern in Chesapeake Bay.

0945 – 1000 Break

Moderator: Christine L. Densmore (USGS, Leetown Science Center)

1000 – 1030 Laurence Pieper (Maryland Department of Natural Resources) - Striped bass disease overview for the past ten years plus.

1030 – 1100 Mark A. Matsche (Maryland Department of Natural Resources) - Survey of gametes and juvenile striped bass (Morone saxatilis) for mycobacteriosis from the Chesapeake Bay: Sampling methods, external lesions, and histopathology.

1100 – 1130 Cynthia B. Stine (University of Maryland) - Microbiology of gametes and age 0-3 striped bass (Morone saxatilis).

1130 – 1200 Christopher A. Ottinger (USGS, Leetown Science Center)- Mycobacterial infections in striped bass (Morone saxatilis) from 

upper and lower Chesapeake Bay: 2002 and 2003 pound net studies.

1200 – 1245 Lunch

Moderator: Chris Ottinger (USGS, Leetown Science Center)

1245 – 1315 David T. Gauthier (Virginia Institute of Marine Science) - Epizootiology of mycobacteriosis in Chesapeake Bay striped bass 

(Morone saxatilis): Large-scale field survey.

1315 – 1345 Andrew S. Kane (University of Maryland) - Mycobacteriosis in juvenile Atlantic menhaden.

1345 – 1415 John M. Jacobs (NOAA/NOS Oxford Cooperative Laboratory) - The influence of dietary intake on the progression and 

severity of mycobacteriosis in striped bass (Morone saxatilis).

1415 – 1445 Andrew S. Kane (University of Maryland) - Mycobacteriosis in Chesapeake Bay fishes: Perspectives and questions.

1445 – 1500 Break

Moderator: John Jacobs (NOAA/NOS Cooperative Oxford Laboratory)

1500 – 1530 Anothony S. Overton (Eastern Carolina University) - Initial investigation of the overall health and presence of mycobacteriosis in Roanoke River, NC, striped bass (Morone saxatilis).

1530 – 1600 Christine L. Densmore (USGS, Leetown Science Center) - Mycobacterial infections in striped bass (Morone saxatilis) from 

Delaware Bay.

1600 – 1630 Desmond M. Kahn (Delaware Division of Fish and Wildlife) - Tag-recapture data from Chesapeake Bay striped bass indicate 

that natural mortality has increased.

1630 – 1700 Wolfgang K. Vogelbein (Virginia Institute of Marine Science) - Epizootic mycobacteriosis in Chesapeake Bay striped bass: 

What is the fate of infected fish?

1730 – 1930 Review panel discussion of technical summaries and associated presentations.
36 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland

Appendix 1: Workshop Agenda.—Continued

Day 2: Wednesday, May 10, 2006

0630 – 0745 Breakfast

0800 – 0815 Opening Remarks (Chris Ottinger and John M. Jacobs)

0815 – 1015 Group Discussion: State of knowledge (Facilitators: Chris Ottinger and John M. Jacobs)

1015 – 1030 Break

1030 – 1130 Panel: Perspective of resource managers (Moderator: Frank M. Panek)

1130 – 1300 Lunch (Review panel makes determination on state of knowledge and knowledge gaps – mostly completed on previous 

evening)

1300 – 1330 Review Panel Presentation: State of knowledge and knowledge gaps (Vicki Blazer – USGS/Leetown Science Center)

1330 – 1530 Break-Out Session: Research prioritization (Facilitators: Frank M. Panek and Fred Kerns - NOAA/NOS Cooperative Oxford 

Laboratory)

1530 – 1545 Break

1545 – 1645 Summary and group discussion of research prioritization session (Facilitators: Frank M. Panek and Fred Kern)

1715 – ? Development of final recommendations for research prioritization by review panel.

Day 3: Thursday, May 11, 2006

0630 – 0745 Breakfast

0800 – 0815 Opening Remarks (John M. Jacobs and Chris Ottinger)

0815 – 0900 Review Panel Presentation: Research prioritization (Vicki Blazer)

0900 - 1100 Break-out sessions for research integration, agency roles, awareness and funding (Facilitators: Kevin Sellner – Chesapeake 

Bay Consortium and Frank M. Panek)

1100 – 1115 Break

1115 – 1200 Summary and group discussion of integration and roles sessions (Kevin Sellner and Frank M. Panek)

1200 – 1300 Lunch

1300 – 1320 Workshop Summary (Chris Ottinger and John M. Jacobs)

1320 - 1400 Observer/press questions, closing remarks, and adjournment (Facilitator: Chris Ottinger)
Appendixes  37

Appendix 2: Prioritized Research Agenda with Estimated Timelines for 

Completion.

Ongoing 2 year 5 year

Overarching Themes

1. Standardized Approaches and Unified Databases

A. Development of diagnostic tools

B. Standardized monitoring

C. Improved coordination among investigators

D. Centralized data management

E. Establish steering committee for B, C, and D

2. Socioeconomic Considerations

A. Outreach programs and web-based information

B. Interaction with public health agencies

C. Development of tools to assess economic impacts of disease 

D. Monitoring of economic impacts of disease

E. Human-health/food-safety issues

Specific Research Priorities

1. Population Level Impacts and Distribution

A. Estimates of mortality associated with disease

B. Spatial and temporal distribution within Bay and Coast-wide fishery

C. Sub-lethal effects on immune function, reproduction, growth, and fitness

D. Density-dependent effects

E. Seasonal effects

F. Movement of diseased fish within the coastal fishery 

G. Integration of disease into stock assessment models

2. Mycobacterial ecology/routes of exposure

A. Transmission studies

B. Distribution in potential vectors (prey/parasites)

C. Relative roles of pathogens in causing disease

D. Growth requirements of various isolates

E. Identification of potential sources

F. Life cycle (obligate vs. opportunistic?)

G. Strain variability and virulence factors

H. Genetic determinants of susceptibility

I. Potential for development of immunity

3. Impacts of Environmental Stressors

A. Influence of environmental variables on disease progression

B. Nutritional/dietary factors influencing progression

C. Genetic/immune factors and stressors
38  USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland Appendix 

3: Participant List.—Continued

Name Address Telephone email

Ana Baya Maryland Department of Agriculture Animal Health Laboratory, 

8077 Greenmead Drive, College Park, MD 20742

301-314-6836 ambaya@umd.edu

Linda Barker Maryland Department of Natural Resources, Fisheries Service, 

Tawes State Office Building,580 Taylor Avenue. Annapolis, MD 21401

410-260-8284 Lbarker@dnr.state.md.us

Vicki Blazer USGS, Leetown Science Center, National Fish Health Research Laboratory, 

11649 Leetown Rd., Kearneysville, WV 25430

304-724-4434 vblazer@usgs.gov

Kay Briggs USGS, Biological Resources Division, 

12201 Sunrise Valley Drive, Reston, VA 20192

703-648-4046 kmbriggs@usgs.gov

Nancy Butowski Maryland Department of Natural Resources,

Tawes State Office Building, B-2,580 Taylor Avenue, Annapolis, MD 21401

410-260-8268 nbutowski@dnr.state.md.us

John Coll USFWS, Northeast Fishery Center, Lamar Fish Health Center, 

400 Washington Ave., P.O. Box 155, Lamar, PA 16848

570-726-6611 John_Coll@fws.gov

Christine Densmore USGS, Leetown Science Center, National Fish Health Research Laboratory, 

11649 Leetown Rd., Kearneysville, WV 25430

304-724-4437 cdensmore@usgs.gov

Andrew Draxler NOAA/NMFS/NEFSC, Ecosystem Processes Division, 

75 Magruder Road, Highlands, NJ 07732

732-872-3054 Andrew.Draxler@noaa.gov

Steve Early Maryland Department of Natural Resources, Cooperative Oxford Lab, 

904 S. Morris Street, Oxford, MD 21654

410-226-0078 searly@dnr.state.md.us

David Gauthier Department of Environmental and Aquatic Animal Health, 

Virginia Institute of Marine Science, The College of William and Mary, 1208 Greate Rd., Gloucester Point, VA 23062

804-684-7908 gauthier@vims.edu

Rod Getchell Cornell University, Department of Microbiology and Immunology, 

C5 181 Veterinary Medical Center, Ithaca, NY 14853-6401 

607-253-3393 rgg4@cornell.edu
Appendixes  3

9

Appendix 3: Participant List.—Continued

Name Address Telephone email

Lewis Gillingham Virginia Marine Resources Commission Main Office, 

2600 Washington Avenue, Third Floor, Newport News, VA 23607

757-247-2243 Lewis.Gillingham@mrc.virginia.gov

Steve Giordano NOAA Chesapeake Bay Office, 

410 Severn Avenue, Suite 107-A, Annapolis, MD 21403

410-267-5660 steve.giordano@noaa.gov

John Jacobs NOAA/NOS; National Centers for Coastal Ocean Science, CCEHBR, 

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, MD 21654 

410-226-5193 John.Jacobs@noaa.gov

Desmond Kahn Delaware Division of Fish and Wildlife, 

P.O. Box 330, Little Creek, DE 19961 

302-739-4782 x19 Desmond.Kahn@state.de.us

Andy Kane Aquatic Pathobiology Center, 

Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742

301-314-6808 akane@umaryland.edu

Howard Kator Department of Environmental and Aquatic Animal Health, 

Virginia Institute of Marine Science, The College of William and Mary, 1208 Greate Rd., Gloucester Point, VA 23062

804-684-7341 x7348 kator@vims.edu

Fred Kern NOAA/NOS, National Centers for Coastal Ocean Science, CCEHBR, 

Cooperative Oxford Laboratory,904 South Morris Street, Oxford, MD 21654 

410-226-5193 Fred.Kern@noaa.gov

Mark Matsche Maryland Department of Natural Resources, Cooperative Oxford Lab, 

904 S. Morris Street, Oxford, MD 21654

410-226-0078 mmatsche@dnr.state.md.us

Eric May NOAA Living Marine Resources Cooperative Science Center,

Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21653

410-651-8342 ebmay@umes.edu

Margaret McBride NOAA Chesapeake Bay Office, 

410 Severn Avenue, Suite 107-A, Annapolis, MD 21403

410-267-5660 margaret.mcbride@noaa.gov

Mark Millikin NOAA/NMFS 

1335 East West Hwy., Bldg. 3, Rm. 1335, Silver Spring, MD 20910

301-713-2341x153 mark.millikin@noaa.gov
40 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland Appendix 

3: Participant List.—Continued

Name Address Telephone email

Chris Ottinger USGS, Leetown Science Center, 

National Fish Health Research Laboratory, 11649 Leetown Rd. Kearneysville, WV 25430

304-724-4453 cottinger@usgs.gov

Anthony Overton East Carolina University, Thomas Harriot College of Arts and Science, 

Department of Biology, Howell Science Complex, Greenville, NC 27858. 

252-328-4121 OvertonA@ecu.edu

Frank Panek USGS, Leetown Science Center, 

National Fish Health Research Laboratory, 11649 Leetown Rd., Kearneysville, WV 25430

304-724-4431 fpanek@usgs.gov

Scott Phillips USGS, 8987 Yellow Brick Road, Baltimore, MD 21237 410-238-4525 swphili@usgs.govLarry Pieper Maryland Department of Natural Resources, Fisheries Service,

301 Marine Academy Drive, Stevensville, MD 21666

410-643-6785 lpieper@dnr.state.md.us

Jim Price Chesapeake Ecological Foundation, Inc., 

P.O. Box 1538, Easton, MD 21601-1538

pres@chesbay.org

Fred Quinn University of Georgia, Department of Infectious Diseases, 

858 Veterinary Medicine Building, Athens, GA 30602-7387

706-542-5790 fquinn@vet.uga.edu

Renate Reimschuessel Office of Research, Center of Veterinary Medicine,

Food & Drug Administration, 8401 Muirkirk Road, Laurel, MD 20708

301-827-8025 rreimsch@cvm.fda.gov

Martha Rhodes Department of Environmental and Aquatic Animal Health, 

Virginia Institute of Marine Science, The College of William and Mary, 1208 Greate Rd., Gloucester Point, VA 23062

804-684-7311x7438 martha@vims.edu

Kevin Rosemary Maryland Department of Natural Resources, Cooperative Oxford Lab, 

904 S. Morris Street, Oxford, MD 21654

410-226-0078 Krosemary@dnr.state.md.gov

Kevin Sellner Chesapeake Research Consortium, Inc., 

645 Contees Wharf Road, Edgewater, MD 21037

410-798-1283 sellnerk@si.edu
Appendixes  4

1

Appendix 3: Participant List.—Continued

Name Address Telephone email

Alexi Sharov Maryland Department of Natural Resources, Fisheries Service, 

Tawes State Office Building, 580 Taylor Avenue, Annapolis, MD 21401

410-260-8288 asharov@dnr.state.md.us

Carl Sindermann CO: NOAA/NOS; National Centers for Coastal Ocean Science, CCEHBR, 

Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, MD 21654 

410-226-5193

Cindy Stine Aquatic Pathobiology Center, 

Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD, 20742

301-314-6809 cstin001@umaryland.edu

Howard Townsend NOAA/NMFS Chesapeake Bay Office, 

Cooperative Oxford Lab, 904 South Morris Street, Oxford, MD 21654

410-226-5193 Howard.Townsend@noaa.gov

Jim Uphoff Maryland Department of Natural Resources, Fisheries Service, 

301 Marine Academy Drive, Stevensville, MD 21666

410-643-6785 juphoff@dnr.state.md.us

Wolf Vogelbein Department of Environmental and Aquatic Animal Health, 

Virginia Institute of Marine Science, The College of William and Mary, 1208 Greate Rd., Gloucester Point, VA 23062

804-684-7261 wolf@vims.edu

Bob Wood NOAA/NOS; National Centers for Coastal Ocean Science, CCEHBR, 

Cooperative Oxford Laboratory, 904 South Morris Street; Oxford, MD 21654 

410-226-5193 bob.wood@noaa.gov
42 USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7 – 10, 2006, Annapolis, Maryland
For additional information:

Christopher A. Ottinger

U.S. Geological Survey

Leetown Science Center

11649 Leetown Road

Kearneysville, WV 25430

John M. Jacobs

National Oceanic and Atmospheric Administration

National Centers for Coastal Ocean Science

Cooperative Oxford Laboratory

904 South Morris Street

Oxford, MD 21654
Ottinger, C.A., and Jacobs, J.M.—USGS/NOAA Workshop on Mycobacteriosis in Striped Bass, May 7-10, 2006, Annapolis, Maryland

—USGS Scientific Investigations Report 2006-5214 / NOAA Technical Memorandum NOS NCCOS 41

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