with D.C. Reid

As hard as it may be to be believed, sharks can sense an electrical differentialof one billionth of a volt. This is the equivalent of sensing the electricalcurrent running between two flashlight batteries set on the ocean floor2,000 miles apart.

Other fish, both fresh- and saltwater, although not as exceptional intheir abilities as sharks, have extraordinary powers to feel electricityin water. Salmon, for instance, can detect voltage changes of .025 of onevolt. They will respond to the electricity emitted from a mooching setupattached to a downrigger from as much as 300 feet away.

All boats with metal parts radiate electrical charge. Sterndrive units,engines, transponders, radar, fridges, radios, fishfinders and any othermetal, including that of downrigger lines and rusty screws react with water,particularly salt water with its high concentration of minerals. Electronspass from boat metal into the water establishing an aura of electricityaround the hull and all the way down fishing line. Even electronic gearnot connected with water will radiate charge through fibreglass hulls.

Zincs are grounded to boat metal to prevent electrolytic pitting, ie.,rust. Zinc is less noble than other metals, for example, stainless steel,thus it donates electrons and gets eaten away. This is why zincs are replacedevery year.

What does this means to fishing? A properly balanced boat will do twothings. It will resist electrolysis and give off a minute positive charge.Less than .5 volt or a negative charge indicates an improperly zinced system.On the other end, a charge greater than .75 volt is too high for fishing.In between, the invisible ion cloud that surrounds your gear can actuallyattract fish to your boat, attracting them right by rods and lines put outby other fishers.

This invisible bathing of electricity can be extremely important to fishing.After changing engines on my boat two years ago, I noted drastically reducedcatches, a situation I was not prepared to accept. A check with a voltmeter- negative clip attached to the engine and positive clip to the downrigger- revealed a .829 volt boat electrical potential and hence indicated thesource of my difficulties: I was actually blowing fish away from the boat.Commercial trollers I have spoken with say they spot schools of salmon formbehind their gear when the correct voltage is dialled on their electronicgear. Change that voltage and fish scoot away. Alter it once again and theycome streaking back.

Different species of bony and cartilaginous fish respond to differentvoltages. The recommended voltages for common sport species are as follows:chinook salmon - .60 volt; coho salmon - .65; sockeye salmon - .75; kokaneesalmon - .65; halibut - .45; lake trout - .65; catfish - .50; rainbow trout- .65; brown trout - .65; cutthroat - .65; black bass - .75; sharks - .40;striped bass - .65; and, sturgeon - .50.

Fortunately, boat electrical potential problems can be addressed. Downriggerscan be modified. Use of a pure lead or vinyl-covered downrigger ball canreduce charge problems, as can isolating the ball from the system. Attach1 1/2' dacron line between the downrigger ball and downrigger line. Thenconnect a small brass extender bar to the top of the dacron for sockeye;to the bottom for other species. Alternatively, use the new braided linefor downriggers instead of stainless downrigger line. In my boat, I foundthat using monofilament line with weights and letting more line out behindthe boat had a dramatic impact on success. I picked up fish on this setupin a ratio of four fish to one when compared with my downrigger.

The best method of producing a fish-attracting electrical charge is aproduct known as a Black Box. This bit of salmon-fishing wizardry oughtto be on the Christmas list of every avid angler. And this includes still-as well as ice-fishers. A wire line dropped from the shore or through theice can be wired to radiate that warm cloud fish find so attractive. Theywill migrate toward it and stay bathing much as we lounge in hottubs. Sooneror later they will get hungry and presto, the lunch is on your line.

Black Boxes come with special sleeves. On the boat, these are attachedto downrigger lines and the accurate voltage for a specific species is dialledin. The system is powerful enough to run up to six downriggers (which isfar more than most boats can handle) and complex enough to deliver the correctvoltage. A table of adjustments down to 200 feet comes with the unit.

The notion of turning a dial to get the fish to swim on over to you mayseem unbelievable while sitting at your computer screen. It will seem alot more plausible when sitting in your boat getting skunked, particularlyif you are a good fisher who regularly brings home fish. As I said, theelectrical potential on my boat changed and until I took corrective action,catches were almost eliminated.

If you’re interested in this recently investigated phenomena orhave questions regarding boat electrical potential contact the manufacturersof the Black Box: