Determiation of potential favorable zones for pelasic fish aggregation (anchovy) in the Balack Sea using rs and gis


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Turkey

Approval Date: 2005

Thesis Language: English

Student: Nilhan Çiftçi

Supervisor: SEVDA ZUHAL AKYÜREK

Abstract:

Fishing is a significant source of food, and constitutes an important source of income in Turkey. Due to the large extent required to analyse the distribution of fish stocks, information derived from satellites play an important role in fisheries applications. Chlorophyll concentration and sea surface temperature (SST) are the most significant parameters which define the fish habitat. The accuracy of these parameters in the Black Sea taken from two different satellites, namely Sea-viewing Wide Field-of-views Sensor (SeaWIFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) are evaluated. Results indicate that both satellites give good estimates of SST but the algorithms overestimate the chlorophyll concentration values. MODIS products are used in the subsequent analyses due to their high correlation with in-situ measurements relative to SeaWIFS products. The cause of the overestimation of chlorophyll concentration is further examined and a general description of environmental variability in Black Sea is done using MODIS products. Anchovy, the most important commercial fish in Turkey, has been selected as the target specie of the study. Level 3 weekly average MODIS chlorophyll and SST products are processed using remote sensing (RS) and geographic information systems (GIS) integration to estimate potential favorable zones for pelagic fish aggregations. Two different decision rules are employed to generate fish stock maps, simple additive weigthing (SAW) and fuzzy additive weigthing (FSAW). The resultant maps are used to visualize the general distribution of Anchovy in Turkish Seas from May 2000 to May 2001. The resultant thematic fish stock maps generated by FSAW analysis represents the uncertainity in the environment better than the ones generated by SAW analysis.