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Fishing Pelagic Species And SIRS HRPT
There is no reason to plot vessel position over blank, deep ocean charts or plotting sheets when fishing pelagic species. Temperature is what guides the movements of the fish and temperature is what you need to guide your vessel as a plotting background. Your nautical charts are of much use when you are close to the dangers of the coast or islands, but they are of little help in fishing capelin, sardinia, anchoveta, tuna, albacora etc.
For fishing temperature sensitive pelagic species, BRIDGE is designed to be used with SIRS and SIRS - HRPT infrared satellite reception systems (See SIRS APT and HRPT Comparison). The Satellite Temperature System, mounted aboard, or on shore, receives and image processes a temperature image. That image file can be printed for distribution on paper, or imported into BRIDGE, and used as a chart background for the plotter. In BRIDGE the cursor represents the vessel position, and is tied to the GPS. The vessel then "moves" about over the temperature isobars on the satellite image or "Chart". You look for the best places to fish on the "picture" of the thermoclines. Simultaneously, you record your catch as you go, and "see" the Catch Icons superimposed over the Temperature Chart. You learn by experimentation, which are the best points on the thermocline for your target species.
One satellite temperature system can provide temperature images to various vessels, whether on paper or equipped with BRIDGE - the only limiting factor is timeliness. Currents and warm or cold water masses change their position rapidly. Generally the best area to fish is at the edge of the warm and the cold water. Because of current changes, we find that the usefulness of an image is limited to about 3 to 5 days. Effectively this means that vessels on short fishing cycles can receive their temperature images from shore, and those on longer fishing cycles should have SIRS APT aboard.
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The above images show an area of warm water created by the Brazil
Current mixing with the Falklands Current,
off the Uruguayan coast. Localized "hot spots" show up well within
the area of warmer water.
In pelagic fishing the environmental conditions in which fish are caught are critical. To gather more information about these factors, BRIDGE collects water temperature, time, date and position data. These factors can also be compared statistically to Catch Records within the database as an aid in determining optimum catch conditions. The Satellite Temperature Image for the big picture, recording the vessel thermometer for amassing the database, and viewing Catch Records graphically in front of zooms of the Temperature Image make BRIDGE a powerful aid to increasing pelagic temperature sensitive catches.
These Catch Icons are the notes you fill in each time you make a catch. They are placed on the chart at the same point that you made the catch. They can be plotted to the screen as all catches made within a certain date range. You can put on the screen an old satellite image, and recall just the catch icons from that time period.
Because the temperature of the ocean is constantly changing you compare the Catch Icons over the Satellite Temperature Chart from within a day or two of when the catch was made. You load the Temperature Chart, and then plot the Catch Records on the chart for just those few days. You have the Big Picture in front of you, the overall current line and associated thermoclines, your marks as put into the system to indicate specific temperatures observed on the vessel thermometer and your "down thermometer", and the scorecard from your fishing as shown by the Catch Icons. You gain an idea of where on the thermocline the best fishing is, and which parts of the thermocline are not as productive.
