Daily Fishing and Outdoor Report




[Cape Cod Times] By Doug Fraser - August 15, 2012 - 

Warming water temperatures might be causing an increase in the number of striped bass that have lesions from a viral or bacterial infection, according to the state Division of Marine Fisheries.

While the number of infected fish is estimated at less than 5 percent of those landed along the entire Massachusetts coastline, the infection rate is higher in fish caught in the Cape Cod Canal and in Buzzards Bay, according to a state advisory issued last month.

So far, there is no evidence of the disease mycobacteriosis that has become prolific among striped bass in the Chesapeake Bay, according to the fisheries division, but the agency urged caution in handling fish because the disease can be transferred to humans through contact.

Mycobacteria are widespread in the marine environment.

The M. shottsii bacteria is the type most commonly associated with the outbreak of lesions in Chesapeake Bay fish. Up to 98 percent of fish in certain areas and 76 percent in the Chesapeake Bay area are believed to be infected with the disease, surveys show.

Researchers at the Virginia Institute of Marine Science, located in Gloucester Point, Va., say it isn't clear whether shottsii can infect humans. It is distantly related to the bacteria that cause tuberculosis and leprosy but does not cause either in humans. Its closest relative is M. marinum, also known as fish handler's disease, which afflicts aquarium and aquaculture workers and can cause small nodules to form on the hands, elbows, knees and feet, joint pain and swelling and swelling in the lymph nodes.

However, human bodies are too warm for the shottsii bacteria to flourish, and an infection usually can be treated with antibiotics, according to the Virginia institute, a research and education nonprofit.

Those reporting issues in Massachusetts have described small red spots on the white underbelly of fish. Any fish with large open lesions or darkened patches of meat should be discarded.

Visual tests have not discovered any mycobacteriosis in striped bass landed in Massachusetts, but samples are getting more intensive testing at the University of Connecticut, Paul Diodati, director of the Division of Marine Fisheries, said Tuesday.

Lou MacKeil, vice president of environmental affairs for the Cape Cod Salties Sportfishing Club, who fishes every day for bass, said at least one fellow fisherman caught bass with spots, took photos and submitted them to the state. But, MacKeil said he has no personal experience with the bacteria.

"I haven't seen any in the fish I've caught, keepers or small. These fish are clean," he said.

Another fisherman dismissed the risk.

"Nothing to really be worried about," Jeff Miller, owner of Canal Bait and Tackle in Sagamore, said.

"It is out there," he said.

MacKeil thinks the rumors about mycobacteriosis might be fueled by groups that want to have the state end the commercial fishery by declaring striped bass a game fish. State legislation to that effect is submitted annually, including this past year, and usually never makes it out of committee.

Part of that strategy this past year was to emphasize health issues with striped bass. Supporters also argue that the state is skewed toward protecting the commercial striped bass fishery at the expense of public health.

"Many, many people have been reporting visible evidence of mycobacteriosis," said Dean Clark, the Massachusetts coordinator for Stripers Forever, the Maine-based recreational fishing group pushing hardest for game fish status in this state.

Clark said his group is concerned there is a lack of funding for research, and that consumers of striped bass should be properly warned of the risks.

There are significant gaps in knowledge and the funding to address them, said Wolfgang K. Vogelbein, a Virginia Institute of Marine Science professor and a principal researcher investigating mycobacteriosis.

The institute's research seems to show the disease has been killing a significant number of fish in the Chesapeake — where the majority of the fish that enter Massachusetts waters each spring originate.

But several key questions remain mysteries, Clark said. Larger striped bass tend to have less evidence and fewer symptoms of mycobacteriosis.

And the larger migrants that travel up north to Massachusetts and Maine seem to become healthier once they are in the cleaner waters of the open ocean with its more plentiful sources of food. Or, perhaps they are simply the ones who have survived the disease.

Researchers are concerned warming ocean waters could help spread marine diseases from the south. Surface water temperatures last summer in the Northeast were the highest ever recorded in the 157 years of record keeping, according to the National Oceanic and Atmospheric Administration.

So far, northern states have relied on colder water temperatures to insulate species from many diseases.

Vogelbein said a lot more funding will be needed to research the connection between the striped bass and mycobacteria in northern waters.


NOAA Studies Shed New Light on Bacterial Disease Affecting Chesapeake Bay Striped Bass Population

land cover data

Mycobacteriosis (shown here in a fish spleen under magnification; bacteria are red) causes a serious and often lethal infection in a wide range of species around the world. There are currently no widely accepted cures.

These bacteria have received increasing attention in recent years because of the discovery of new species of the bacteria in fish hosts, sharp increases in incidence rates in wild fisheries, and the ability of a few species of the bacteria to infect humans.

If you’re an angler in the Chesapeake Bay region, you may be familiar with the term ‘myco.’ It’s slang for mycobacteriosis, a serious disease that affects up to 70 percent of adult striped bass in the Bay.

For years, scientists have been racing to understand more about the harmful bacteria that cause this disease and potential implications for the management of the fishery.

This year, we learned much more about the problem thanks to new research conducted by NOAA and partners. Two studies published in 2009 provide important new clues into how widely this disease is distributed, as well as how long it has been around in the Bay region.

In a study published in the Journal of Aquatic Animal Health in October, researchers found two types of mycobacteria common in striped bass in Bay-area white perch. The study also found mycobacteriosis in stripers locatedoutside of the Chesapeake Bay region.

While scientists are not surprised to find mycobacteria in striped bass from other areas, it's not clear if this indicates that the bacteria are moving to new areas or if the findings are a result of increased surveillance. Likewise, study authors note that it's 'not entirely surprising' to find that the same strains of mycobacteria infecting striped bass are also infecting white perch, since this fish is a close relative and shares similar habitats and habits. Nonetheless, the report marks an important step forward in what is known about the disease. In addition, the findings point to the need for more investigation into other potential host species and geographic areas where mycobacteriosis may be found.

In a second study published in Diseases of Aquatic Organisms in July, researchers found evidence of mycobacteriosis infection in striped bass dating back to 1984 by examining archived bass tissue samples. Previously, the earliest known cases of the disease stemmed from 1997.

This finding establishes a more accurate timeline of the presence of the disease in the region. It also underscores the importance of keeping archived samples of animal tissue in storage for use in studying the causes, distribution, and timeline for a given disease.

Together, the two studies may help scientists get closer to answering basic questions about the distribution and potential sources of mycobacteria in the region.These answers are needed to maintain the health and vitality of one of the most important commercial and recreational fisheries in the Mid-Atlantic region.

*The Cooperative Oxford Lab, administered by NOS, is a shared research facility between NOAA, Maryland's Department of Natural Resources, and the U.S. Coast Guard.

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