Trapping
Click the small image at any time to go right to the first of the full sized trap image windows.
Trap set points
You need to know about the bottom where you are fishing - and you know almost nothing directly about it. You may have some begin / end marks and lines on a plotter marking trap lines that have worked in the past; you may know that an area is better at one season or another; you may have thousands of depth marks on your plotter, each one showing the depth at that point, perhaps even colored by depth range - and you've got lots of effort expended by your brain to try and figure out how the bottom looks and where the shellfish are going to be NOW - because that's when you've got to find them.
And next month, they will probably have moved. You pursue shellfish through their annual cycle, there will be the times when they congregate and are easy to catch, unfortunately this is generally a time of relatively low prices. Then there are other seasons when the lobsters or crabs are more difficult to find, and the prices are higher. With Marimsys BRIDGE you will create the only detailed cartography inexistence of the bottom where you are fishing. The software precisely positions catches and marks that you make on those charts, and you follow the shellfish, area by area on their annual migrations. When you understand the different zones in which the shellfish are found at different times of the year, and the different types of habitat which they look for in those different season - because the micro-habitat they look for changes through the year - you can strongly improve your catches, year-round. And if you're in a part of the world which is being hit with trap limits - you need to increase catches per trap - and Marimsys BRIDGE helps you do it.
Marimsys BRIDGE makes it possible for you to see the bottom. The system takes soundings data while you are fishing, you send that data to Marine Imaging over the internet, we make it into charts and send your charts back to you, pre-calibrated. These charts show the bottom with its places for shellfish to feed, hide, reproduce and rest and its' obstacles. You can determine in which sort of terrain the crabs, lobsters or shrimp are found - in which season of the year. And then looking at the charts, you can "see" more of the same habitat close-by, and increase the number of productive trap lines. It is a lot faster and less expensive to check out a new area by taking soundings automatically with your boat while laying a few trap lines, than it is to sample the area with just laying trap lines.
In our experience shellfish will have large scale movements throughout an annual cycle. They will typically move from shallower to deeper water as they spawn, shed, perhaps go dormant, and pursue seasonally available food supplies. These changes in general area are accompanied with specific changes in "micro-terrain" within those general areas. For instance, they may congregate on shallow sandy banks at spawning season, under ledges and in caves to shed, go down into deep water when they go dormant and come up into intermediate depths to eat some larvae that is hatching in September. These are part of the annual cycle of the shellfish, and being in the correct general area, and furthermore laying your traps in the correct type of micro-terrain for that season are the most important variables separating traps from highly productive traps. You may know expert fishermen who seem to have higher yields per trap all year round, who have with a process of huge numbers of trials and errors found those places to lay trap lines - they have found places generally that correspond to what we describe above. We guarantee that with Marimsys BRIDGE and Marimsys Charts those fishermen will do still better - because they can "see" what distinguishes their highly productive areas, and easily find other similar areas which should have the same productivity.
Obstacles - rockpiles, ledges or reefs which would catch and tear the warp are visible on the chart - you can avoid them without having to find them first with a line or a trap. You can look at a complex bottom, filled with caves and ledges - the kind that lobsters live in and under, protected by the obstacles - and plot out trap lines through the obstacles - right in close to the sides of the ledges. You can estimate the effect of currents on bottom terrain, both to help you find fish, and to estimate the drift of the traps on the way down - so they land exactly where you want them.
In the next illustration, the main flow of the cold and powerful Humboldt Current goes by, south to north a few miles to the west. Where we are fishing is the inshore side of the Humboldt, up on the edge of the continental shelf where it runs east-west for a bit. These sunken river valleys, created by faulting, were gouged-out back in the time of the glaciers. The underlying rock rises with every earthquake, up out of the Humboldt trench, and pushes this whole area up, creating a jungle of faults. The weather has been lousy for a few days and you haven't been able to lay traps, but the spawning season is beginning - where exactly are the centolla?
As the current goes around these projections and valleys it eddies, setting the traps in directions which are unpredictable from the surface - unless you happen to have this chart and can project how the current will be jogging. The high ridges, protruding into the current flow and surrounding the valleys pushes the current up into mini-upwellings which slows the water flow and causes sediments to fall out on the lee sides and into the valleys. The crabs like the muddy sediments of the valley bottoms when they are feeding. They'll use the valleys for corridors when they are spawning - and then they'll go back down the same corridor, feeding on the way. Except, that is, when they seem to move into the rocks to hide and rest up a bit, right after the spawning when they are hungry and tired.
The Humboldt current eddies flow erratically up and down these valleys. The force of this incoming current can bare the rocks at the narrow points, or where the valley makes abrupt turns. At the tops of the ridges jutting up into the currents, there will be almost bare (and jagged) rock. Those rocky heights are tricky to lay traps in, but it can be done with Marimsys charts and is the best place to catch the crabs after spawning. But, the problem now before the spawning begins is to determine at what depth they are found as they travel up the valley - or have they already gotten up into the shallows?
If the crabs are travelling, we want to fish the zones where the sediments fall out at the bottoms and the sides of the valleys. This provides easy travel on the mud, a bit of easily available food during the migration, and the protection of the rock ledges. This chart enables you to see the valley sides, steep places that won't hold enough sediment to cover the rock, knobs that stick out, and one way cul-de-sacs. You can also estimate the local micro-effects of the current, if you know which way it is coming, you can look at the rock projections and make a pretty good guess how it will carry your traps on the way down.
Laying the traps in close to the sides of the valley, where the crabs can hide in the rocks at the sides, and move out into the valley to feed as they maintain a general progress up the valley seems to be the best strategy. If we really needed to lay the traps into the sides of the ledges, we'd use the Marimsys Charts with 1 or 2 meter contours. But, for this trap line, the chart shown displays a large area of the surrounding valley well, and we really don't need the extra detail.
Here's the haul 
The arrows indicate the position of the haul points for the individual traps. In Chile, 12 cm front to back on the carapace, that's about 5 inches, and weighing between a bit more than a kilo is legal. 3 or more per trap is a good average. Each trap that has 4 or more legal centolla gets a catch icon while hauling. This was actually quite a good set.
Analyzing where those above average hauls occur is the key to making the next set even better. When we look at the pattern of the catch icons we see that the crabs are well along in moving up this valley. They seem to be holding nearer to the sides of the ledges than to the holes - they're looking for cover more than for food as they go up the valley for the spawning. The next set will be in a bit shallower water, further up the valley, laying close in to the ledges.
What about the currents that are affecting the sets in this valley? If we're laying traps in close to the ledges we'll have to use a Marimsys Chart with higher resolution, and perhaps lay the traps closer to the ledges. To check the currents we'll look at the set and haul points for the traps.
Here's the image to compare set and haul points and determine current
Comparison of the set and haul points indicates that the traps are generally being carried out the valley - the tide was setting stronly below the surface. OK, even though the tide table said that the set ocurred with the end of the incoming tide, and the haul occurred at the ebb, and there was a west wind and surface current for both the set and haul - the subsurface currents were ebbing strongly. There were a few exceptions to the general trap movements around the ledges where there is a current eddy. OK take that in consideration on the next set and do a still better job.
A bit of explanation about the screen: the upper left position bar gives cursor position, the bearing from the ship to the cursor, and vessel speed. The instrument bar along the bottom tells you that instrument data is entering, ship position, time, date, course, vessel speed, echosounder depth, temperature and the status of the Autolog. The ship position is represented by an arrow, and right below the tip of the arrow, you'll see the depth shown for the vessel position on the Marimsys Chart - 179 meters - same as the echosounder reading on the instrument status bar.
With the image, you understand this area and its ledges and valleys, and how the current flows. If you noted greater than average crab concentrations on the small step ledges, or on the lee side of the rock projecting into the current, or down in the bottom of the valley - you've learned where they are today. You file that away for future use, it is valuable information; and you click the next Marimsys Chart to the screen, spot the areas where the crabs will be and go directly there - because you can see the habitat. When you learn what the good spots look like in today's conditions, and if you've got the charts - you can find more of them and go directly there. That puts a lot of crabs in the hold and saves fuel - or, you could call it increasing productivity.
With Marimsys BRIDGE and Marimsys Charts you have a view of the bottom. You can visualize your fishing in front of that view of the bottom. You will observe better fishing in some types of terrain, and not-so-good fishing in other types of bottom. You will observe bottom that will catch your gear - and be able to fish right beside it, not on it. You will spend more time fishing in the good areas, and less time in the others. It adds up to more highly productive fishing days.
BRIDGE is a full-fledged electronic plotter that uses many different types of charting. Notable among the types of charts it uses are Marimsys Charts, prepared by us from data gathered by your own vessel. These provide a view of your workplace - the seabed - that is unsurpassed. Scale can range down to about 1: 2500 for the difficult bottom where you need that level of detail to work. Our Marimsys BRIDGE System gathers the data to make Marimsys Charts of the bottom, and also displays many different types of charts such as: Satellite Bathymetry, and Satellite mGal Gravity charts for exploration of new areas; and of course, normal Sovereign Nautical Charts.
These Marimsys Chart images are very highly detailed views of the bottom and provide extensive habitat information, as well as make the obstacles to fishing visible. This means that you see the character of the ocean bottom where you are making (or not making) catches, and can visualize the movement of currents and eddies over and around the terrain. You can make connections over what combination of bottom type and feature (hill, valley, slope or flats) and current (ebb, set, various current layers, temperature, and season) are productive - and which combinations are not. This system is a fishing system and is designed to help you answer the question: Why am I catching (or not catching) right-here right-now?
F/V Friosur VIII and Captain Jon Ivar Halvarsson collected the data for these Marimsys Charts. Grimur Eiricksson and Carlos Vial I. kindly gave us permission to use these images, the property of Friosur S.A. Our thanks to them and the Friosur team. Latitudes and Longitudes appearing in the screens have been changed to protect the actual locations.