Early last week, I caught a fat striped bass. The fish was not particularly large, probably about 15 pounds but a nice size for the table. I paid no attention to what appeared to be a slight red sore on its side, figuring it was probably due to the fight.
My practice when I plan to keep a bass is to cut the fish in the gills immediately to bleed it, both to end its struggle and preserve the quality of the meat. I trim off the dark red meat, which I think adds little to the flavor.
When I looked at the fillets I saw several dark spots in the otherwise white flesh. It was not an appetizing sight. A closer examination revealed small capsules or cysts. To paraphrase my daughter — gross.
I put the fish in the refrigerator and went to that source of all knowledge and opinion, Google search. For a second view, I also contacted the folks at the Mass Division of Marine Fisheries (DMF).
DMF striped bass biologist Gary Nelson told me that the department’s resident parasitologist thought the fish was infected with black spot disease “which is a life stage of a trematode worm known as fluke.”
He added, “The larvae create cysts under the skin and in the flesh. The fish is edible in that condition, just cook it as you normally would.”
Do what? I emailed back and told him It did not sound very appetizing. I asked if he had any sense of how widespread it was, since this was the first time over many years I had ever spotted any black spots in any bass I had kept.
“I don’t have any statistics, but I see it occasionally in striped bass and other fish,” Gary said. “It is one of the most common diseases. Luckily, it usually isn’t lethal.”
Did you catch the “usually isn’t” part of that answer? I imagined myself on the cusp of being the first human to contract mad striped bass disease.
A Google search for dark spots in striped bass brought up several references. The Maryland Department of Natural Resources website posted a question from a fisherman, Paul Puher, about rockfish, their name for striped bass. It was very similar to my experience.
“I recently caught a rockfish that looked very healthy,” Paul said. “I filleted it and saw these black spots deep in the meat. I cut through it, and it appeared to be a dead something. Can you please tell me what these things are; should the fish be thrown out, is this normal?”
Maryland fish health biologist Mark Matsche responded.
The black spots are the larval form of a parasitic worm known as digenean trematodes. This infection is often called “black spot disease”, and in some fish, particularly small individuals, the worms may be visible through the skin. There are many different species of digenea worms, and most are white or yellow in color. The black appearance of the worms is a result of pigments that may accumulate around the parasites as part of the fish’s immune response. This black pigmentation of the worms doesn’t always occur, and the spots may appear white or yellow (“white spot” or “yellow spot” disease). Most species of fish may be susceptible to digenean infections. Digenean worms have a fairly complex life cycle, which involves aquatic snails or other invertebrates as the initial host; fish as an intermediate host; and mammals, birds, or other fish as the final host; the intermediate form of the worm penetrates and burrows into the flesh of fish.
Most digenean parasites are not dangerous to humans. When few in number, black spots can be trimmed from the fillets, and thorough cooking will kill any remaining worms.
My wife and I considered what to do, fish cakes perhaps. There did not seem to be enough beer if the fridge to wash down fish cakes with cooked trematode worms.
I imagined the farm to table folks could sell it if they charged enough and added Vineyard in front of worms on the menu, but it was not for us. I was not reassured by the notion that all I had to do was cook the bass. I used the fish for crab bait.
Red pots mark research project
I was curious about two red pot floats marked Shellfish Department, one off each Tashmoo jetty and well within casting distance of the many fishermen who haunt Tashmoo hoping to catch a glimmer of an albie or a bonito.
I contacted Tisbury shellfish constable Danielle Ewart who put me in contact with Shelley Edmundson of the University of New Hampshire. The shellfish department is assisting Shelley with a research project on the movement of conch in and out of Tashmoo. The buoys are attached to electronic counters that count each time a tagged conch moves in or out of the inlet.
Shelley could not have been nicer and expressed concern that any fisherman might lose a fish on her account. Because I never catch a bonito or albie, I could not offer her an informed opinion on whether the floats would be less of a fish hazard if moved closer. My view is I will just treat the floats as one of many obstacles, which include other fishermen, in the interest of science.
False albacore finally showed up. Bonito in lesser numbers. The striped bass fishing seemed to slow last week.
This Saturday is bass day. The Derby will hand over $500 each to the fisherman who catches the largest bass from the shore and from a boat on October 5.
There is plenty of reason to fish for a striped bass. The current Derby leader as of Tuesday was 35 pounds. That is a pipsqueak by classic Derby standards.
Boat storage tip
In the weeks ahead, many fishermen will put their boats away for the winter. For many Island boat owners, their preparations will consist of a blue tarp tied down with rope. Cosmetics may not be important but the gas that is left in the engine could mean lots of trouble when spring arrives because it contains ethanol.
The Boat Owners Association of The United States (BoatUS) advises recreational boat owners to take special precautions with gas left in the engine.
Ethanol absorbs water. If ethanol becomes saturated, which can happen when it sits for long periods, the ethanol separates from the gasoline, forming two separate solutions, BoatUS said. This is called phase separation and it’s bad news for the engine. An engine won’t run on the (water-soaked) ethanol solution, which sinks to the bottom of the tank and is highly corrosive.
“Today it’s highly likely that your boat’s gasoline contains a mixture of up to 10 percent ethanol, which is known to damage engines and boat fuel systems, especially over the long winter storage season,” BoatUS said in a press release. “If you have a portable gas tank on your boat, try to use as much gas as possible before you put the boat away at the end of the season. Any remaining gas or gas-and-oil mix that’s left in the portable tank can be put in your car or outdoor power equipment, respectively. The goal here is to use it up as quickly as possible.
“If your boat has a built-in gas tank that cannot be emptied, add a fuel stabilizer, and then fill the tank as much as possible, leaving just a smidgen of room for expansion. This will greatly reduce the amount of moisture laden-air that can enter through the tank’s vent and potentially condense on inside tank walls over the long storage season.”