Electronic section tagging for purse seine fishing

It is important to haul the cork line and the sink line of purse seines in synchrony. Failing to keep the lines synchronized may cause damage to the net and escape of fish with small chances of survival. Today, synchrony is achieved by attaching colour-coded visual markers. As these markers are often hidden by netting, detecting them may be difficult and requires constant attention from the operator. At nighttime, visual markers require the use of lights. This light attracts fish to the pulled end of the net, causing risk for damage to the net and dangerous situations in bad weather. It also causes loss of quality of both the current and the next catch if the net is not thoroughly cleaned between hauls. This project is developing an electronic system for monitoring the hauling process. This will free the operator's attention from constantly looking for visual markers and make the use of extra light unnecessary. The main idea is to place electronic tags at regular intervals along the cork line and the sink line. By detecting the tags both where the net is hauled and where it is deployed, the system will be able to estimate how synchronously the net is being hauled, as well as how much of the net has been deployed or retrieved. This information is also useful for the captain, as it is gives him a better estimate of how much net is left during the final stages of the deployment operation. It is also important for deciding when and how to steer the vessel relative to the wind in bad weather, as well as for regulations and practical considerations related to deciding whether to take aboard the catch. A theoretical analysis of different candidate technologies for the electronic tags has been carried out. Several components have gone through testing in the laboratory to determine detection ranges for the tags. Furthermore, it has also been tested how seawater and mounting of the tags on the cork line and sink line affected the detection range. Different systems have been mounted on board M/S Leinebjørn with test tags mounted on the net and software to monitor the tag detection. The tag detection has been continuously tested during fisheries. During the autumn of 2018 a system based on active Bluetooth technology was tested on board M/S Leinebjørn. The detection rate during this testing was good. Electronic tags suitable for installation on the purse seine have been produced. A test of integration of the new tags in the system has been carried out successfully in 2019. After and upgrade of some components of the system, the tag detection was tested in November 2020. The test results showed good detection rates. A graphical user interface was developed and made available as a web application on the local network on board M/S Leinebjørn. The user interface shows the tag detection and an indication of whether the cork line is in front of or behind the sink line. The user interface also enables configuration of the system.

Prosjektets resusultater forventes å bidra til at Kongsberg Maritime vil kunne tilby notinstrumentering som gir funksjonalitet for elektronisk overvåking av nota. For fiskerene vil mulighet for elektronisk overvåking av nota under haling forenkle arbeidsoppgavene til operatøren av kraftblokka og kunne gi mindre problemer med skeiv haling av nota. Mindre behov for lys i mørket forventes å gi mindre risiko for at fisk samles i sekker i nota og gjør skade under haling.

It is important to haul the cork line and the sink line of purse seines in synchrony. Today, this is achieved by adding colour-coded visual markers. As these are often hidden by netting, this is not always easy. Failing to keep the lines synchronized may cause damage to the net and escape of fish with small chances of survival. At night time, visual markers require the use of lights. This light attracts fish to the pulled end of the net, causing risk for damage to the net and dangerous situations in bad weather. It also causes loss of quality of both the current and the next catch if the net is not thoroughly cleaned. This project is developing an electronic system for monitoring the hauling process. This will free the operator's attention from constantly looking for visual markers and make the use of extra light unnecessary. The main idea is to place electronic tags at regular intervals along the cork line and the sink line. Detecting these tags both where the net is hauled and where it is deployed, the system will be able to estimate how synchronously the net is being hauled, as well as how much of the net has been deployed or retrieved. This information is also useful for the captain, as it is gives him a better estimate of how much net is left during the final stages of the deployment operation. It is also important for deciding when and how to steer the vessel relative to the wind in bad weather, as well as for regulations and practical considerations related to deciding whether or not to take aboard the catch. The primary objective of the project is to develop a system that provides information about the deployed net length and synchrony during both hauling and deployment. The secondary objectives are: - Develop a robust and efficient electronic tag detection system. - Develop a method for estimating the net status based on the detection system and vessel instruments. - Develop graphical user interfaces for configuration and presentation.