Mapping System of Skipjack’s Fishing Ground in Prigi Waters of East Java

Abstract

Prigi waters locates in the south of East Java is one of the potential fishing grounds in Indonesia which the main commodities are skipjack and tuna. These waters are a strategic place for trolling fishermen and either local purse seine fishermen nor fishermen who come from the outside of Prigi waters. In 2011, the production volume of tuna in Prigi fishing port is 717189 kg with production value to 6 761 309 850 IDR . In addition, the amount of fishing gear in 2011 is 86 units and purse seine is 159 units. Tuna fishing season is from June to October and peaking in August and September. But the welfare of fishermen, especially for fishermen trolling is under feasible because the benefits are low. The fishermen determine the skipjack fishing area systems with hunting and some have been using FADs and light as a tool to collect hordes. These devices are led to the arrest of a very high operating cost. Suspect in a fishing grounds skipjack in the waters of Indonesia, is already available in the form of map forecasting potential fishing grounds through the Marine Observation and Research Agency (MORA) which can be obtained free of charge on the internet. However, this facility has not been used by fishermen in Prigi because of the information displays is not match with the real conditions of fishing trolling in waters Prigi. Mapping system is a fishing area covers various aspects which increase a result of fisheries catches including tuna. These aspects include aspects of human resources, fish resources, fishing season, fishing gear technology and a fleet of fishing vessels. The objective of this study is to make the fishing grounds mapping system in Prigi Fishing Port, to evaluate the mapping systems that support skipjacks fishing grounds in the waters of Prigi and to make mapping of skipjack fishing ground in Prigi waters. Hopefully, through this research produces fishing grounds mapping system in accordance with the small-scale fisheries that can completes map forecasts that have been made by MORA. The result of the map of skipjack fishing grounds in Prigi waters which analyze with the mapping system will also be applied in other grounds of Indonesia with an adjustment to the character of each region. This study was conducted in three phases. The first phase of this study is field survey which the study was on last January 2012 in Prigi Fishing Port. The second phase is data collection of tuna catches and interviews with the fishermen from July to October 2012. The third stage is downloads the image of sea surface temperature (SST) and chlorophyll-a level 3 on the Aqua MODIS satellite which free from clouds cover and process data from the internet to get information and oceanographic parameters such as SST and chlorophyll-a which began in November 2012 to February 2013 in the Department of Utilization Fisheries Resources, Faculty of Fisheries and Marine Sciences (FFMS) Bogor Agricultural University (BAU). In addition to analyzing the catch, fish size, SST and daily chlorophyll-a, time series analyze was also carried out from January 2007 to August 2012. Tuna distributions was analyzed by combined the oceanographic parameters of SST and chlorophyll-a to production catches and fish sizes through multiple linear regression. Mapping system fishing grounds which analyze from Structural Equation Modeling (SEM) is used to create a map of potential skipjack fishing in the waters of Prigi. Observations obtained during the study forecasts that the map of potential fishing grounds issued by MORA is not used by fishermen and even information about the map are difficult to obtain from the Prigi department of marine and fisheries. Fishermen argue that the map is not in accordance with the conditions of fisheries in Prigi and only useful for large-scale fisheries such as purse seine fishery from Bali and Jakarta. In mapping system of fishing grounds found that fishing operations in waters Prigi still traditional hunting ways. Aspects of fishing gear modifications, the use of FADs and light is the main choice of fishermen trolling in Prigi to increase fish catches. This results in huge profits for perpetrators of fishing but on the other hand it is adverse impact on fish sustainability resources, especially for tuna. Technological aspects of fishing have been good influential in the mapping system of skipjack fishing grounds in Prigi waters compared to the human resources aspect, fish resources and boats. Sea surface temperature (SST) in the Prigi waters during the study from July to October 2012 can be considered cool. Seasonal patterns obtained during the last 6 years (2007-2012) shows that the highest SST occurred in west season and eastwest transition season. Meanwhile, the lowest SST occurred in eastern season and begins increase within the east-west transition season. The content of chlorophylla concentration was highest in east season and east-west transition season. It is lowest in the west season and the west-east transition season. In the west season, the wind speeds is high so the fishermen does not do the capture operation. The same thing occurs in the east season with high wind speeds but surface currents causes front and upwelling and thus increases eutrofication waters. Therefore, fishermen still do the fishing operations because it is a condition that favored by tuna and skipjack. The resulting map of fishing grounds are classified into two categories which is Java trolling fishing grounds and fishing grounds Bugis trolling. Bugis trolling fishing ground is mostly within FADs which the location is further towards to the open sea (> 26 miles), while the local fishing ground is closer to beach without the use of FADs. Map extents research is narrower about 10168 mil2 and still spread around the south of East Java. Forecast map issued by MORA more spread out to the south of Bali and Yogyakarta southern reaches 18669 mil2 and has the farthest distance into the open sea.