Bharat Electronics’ fish finder helps net rich haul

Indian fishermen have long believed in luck and climatic conditions to net a good catch from the sea. Perhaps that is the reason why Indian fishermen have been able to catch only 4 million tonnes per annum, while the actual potential is said to be 2 million tonnes more. Srikanth R P has the details on an innovative device developed by Bharat Electronics, which can help Indian fishermen net a bigger catch

Indian fishermen are no strangers to technology. They have been using potential fishing zone (PFZ) maps sent by the National Remote Satellite Agency (NSRA) based at Hyderabad. PFZ maps are useful since satellites locate shoals of fish and mark them up on a map. The position of fish shoals doesn’t change for at least three days, so the fishermen use the maps and a mariner’s compass to hone in to the general area of marine plenty.

While PFZ maps are useful in narrowing down the location, the fishermen cannot reach the exact location as there aren’t any determinable landmarks. The outcome being that fishermen end up spending more time to reach the fishing location and return back, resulting in more consumption of fuel during every voyage. Based on mere guessing of fish shoal location, the fishermen used to do blind netting. If the catch was good, they continued netting in that particular location. If not, they moved on till the right location was found. Since the fisherman did not know what lay beneath, many a times the nets would get damaged. The department of ocean development (DOD) was looking for a system or a device wherein the fishermen could reach a PFZ location by the shortest route and confirm the presence of fish shoals once they reached the particular location.

Bharat Electronics, a government of India enterprise catering mainly to the defence sector, has done just that with its Integrated Fish finder and Navigational System—an innovative system based on GPS (Global Positioning System). The system consists of a GPS receiver and an echo sounder. The data on the fish shoals traced on the PFZ maps can be entered into the boat’s GPS by entering the longitude and latitude of the fish shoal. This helps the fishermen to zoom in on the actual location. Besides this, the system also provides details on the speed of the boat, current time and expected time of arrival to enable the user to reach his destination effectively. During the navigation, if the course deviation is more than 150 metres, an arrow symbol along with the direction appears on the screen of the device to enable the fisherman to correct his course. And if the deviation is more than 500 metres, then an audio alarm is sounded to alert the people in the boat.

After reaching the location marked by the PFZ, the system identifies the shoal of fish through the fish finder. The fish finder helps to measure the depth of the sea bottom and fish shoal accurately. The device works on the principle of echo sounding to locate fish shoals up to a depth of 150 metres to 500 metres. A transmitter in the device provides a burst of pulses in the form of electric signals. A transducer mounted at the bottom of the vessel converts these signals into sound waves and propagates them to the water downwards. The sound waves get reflected by the seabed as well as the fish shoals. The reflected sound waves are again converted into electric signals by the transducer and the signal is passed onto the display circuits. Whenever the signals hit a shoal of fish, a fish alarm is sounded. The fishermen can confirm the presence of shoals by looking at the LCD display that provides viewing of the type of fish as well as the seabed. After confirming the location, the fisherman can cast his net accurately to complete the catch.

Additionally, data for more than a hundred locations can be entered in the system. What may be more relevant is the fact that the home location can be also be entered—after fishing, just by pressing a button, the fisherman can reach his base with the help of the navigational system. Moreover, the system has a provision of sounding a shallow alarm if the depth is less than 5 metres. This would help the fishermen in preventing their ships and nets from getting damaged.

To test the validity of the device, Bharat Electronics conducted extensive field trials and obtained feedback from fishermen in Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Goa and Gujarat. The trials proved to be successful with the device achieving what the authorities had only dreamt of. Accurate navigation, sounding of an audio alarm as soon as a fish shoal was reached, leading to saving of both time and money and more importantly, a better catch. Moreover, the feedback established that the fishermen saved around 150 litres of diesel and around ten hours per trip.

The success of this device can be seen from the fact that the company has managed to sell around 238 units to various fisheries and fishing companies across the country. Looking at the potential of this device, the company has also started conducting field trials in countries like Mauritius.