Assumptions of this study provide that prohibition of sardines fishing during spawning season will improve fish stocks. Biological component includes catch, species composition and production of adults and juveniles, as well as spawning patterns and otolith analysis. Closed fishing season was enforced to vessels with commercial-scale harvest three months per year for a period of three years starting December of 2011. Zamboanga Peninsula waters covers western municipal and national waters of Zamboanga Del Norte, waters bordering south and eastern waters of Zamboanga City and southern portion of Zamboanga Sibugay. Daily catches from 13 commercial fishers and 37 municipal fishers in eight key landing sites were monitored. a sets. Significant improvement in landed catch of sardines were observed before and during the implementation of the fishing closure. Increase in the frequency of large-sized S. lemuru was also observable. Spawning patterns evidenced by GSI values differ in two areas of the region. Northern Zamboanga Peninsula may require spawning protection during November to February. Southern Zamboanga Peninsula may implement a closed fishing season during June to September. Some periods of low sardines production despite favorable environmental conditions may also be due to high proportion of predatory fish species or fishers’ preference.
