Sunday, October 4, 2009

Going up to Minnesota to visit my Grandfather's ranch was a real adventure. There were so many cool things to do: Riding horse, hunting and, of course, fishing at the lake.

One of the important lessons I learned on the ranch was that there is a little good and bad in everything. While I loved riding the horses, I really didn't enjoy getting up at sunrise to help shovel urine soaked hay and horse manure out of the stalls. The obvious bad part to this chore was the oppressive odor of horse excretions in the pre-dawn morning. The good side was that this mixture of hay and horse manure would eventually become great compost after being in the fields, and over time would end up being a great place to dig for fishing worms.

My Grampa always said, "Any country where you can bag up animal poop and sell it to people has to be a rich country." He also had another phrase about politicians and poop, but I don't think I better go down that horse trail right now.

Fortunately, we don't have to dig for worms in the Keys -- which is a good thing since most of the fishermen I know are too lazy to dig in the coral for bait. So exactly what do worms have to do with fishing in the Florida Keys? Well, if you have ever filleted an amberjack you probably know exactly what type of worms I am getting around to -- marine parasites.

A while back, a friend of mine caught a big amberjack. As he filleted the fish he noticed large worms and cysts in the meat. Disgusted, he immediately discarded the entire fish. The next day he asked me if I had ever seen worms while cleaning fish. I told him it was pretty common in certain species, but all he had to do was just cut them out. He looked at me as if I were crazy, saying there was no way he was going to eat fish with worms!

The fact is, most (if not all) fish contain worms (i.e. parasites). Thankfully, many of these marine parasites reside in the fish's intestinal tract and, therefore, usually pose little harm. The worms/eggs/larva that do migrate out into the flesh are usually so small that they are frequently overlooked during the fish cleaning process. Certain species of fish are known to harbor species of parasites that infiltrate the flesh and become large enough that they are easily seen in the flesh.

The majority of fishermen in the Keys are familiar with the worms present in amberjack. Surprisingly, many Keys fishermen do not realize that groupers are also at risk for carrying nematode worms. Red and black drum, and spotted sea trout, are very prone to marine parasite infestations. I jokingly say this is the main reason they started serving redfish blackened, so the tourists wouldn't be able to see the worms!

The good news concerning parasitic worms is that most of these worms do not usually harm the fish populations. Perhaps the best news of all is that there is almost no hazard to humans who eat fish containing parasitic marine worms -- IF -- it is properly processed, cooked and/or frozen. The FDA recommends that fish be "flash" frozen for seven days at -4 degrees Fahrenheit or -31 degrees Celsius for 15 hours (most home freezers are not able to attain these low temperatures) to eliminate the risk from parasites. Cooked fish and smoked fish should reach an internal temperature of at least 140 degrees to render the parasites harmless. Raw fish served in marinated mixtures such as ceviche should be made from fish that was commercially frozen.

Some of the more prevalent parasites found in fish are roundworms, hookworms, and whipworms. The roundworm is a very common parasite and can result in a disease process known as ANISKISIS. If you eat undercooked or raw fish and you swallow a live nematode larva, you run the risk of developing severe gastric upset as the larva attaches and/or penetrates your intestinal lining. The good thing is that the majority of parasitic larvas find humans to be a very inhospitable host, and only live for a week or so after being ingested.

I know sashimi and sushi are both trendy delicacies, but I still have a hard time bringing myself to eat "bait." When I glance over a menu in one of these restaurants, my mind starts running amuck with visions of roundworms, tapeworms, and fluke worms wiggling around in my main course. Thankfully, legitimate sushi restaurants use mostly flash frozen fish which renders all of the parasites harmless. In addition, professional sushi cooks are trained to carefully examine fish for parasites.

Obviously it is important to handle your catch properly to avoid food borne illness. I have seen a lot of different "techniques" at the fish cleaning station and I think there is considerable opportunity for the fish filets to become contaminated during this process. I have watched as guys filet the whole side of the fish with little regard as they slice right through the intestinal organs. While this does serve as a quick way of removing the filet, it unfortunately results in brown intestinal contents oozing all over their "fresh" fish filets.

Of course, there is always one "macho man" out there, cleaning fish, who has to take a chunk of raw fish and slurps it down as his buddies stand around chuckling. All I can say is ... good luck with that.

Capt. Pete Peterson welcomes comments and suggestions sent to petersonventures@aol.com.