Hilsa catches from rivers are shrinking in spite of a rise in overall production, due to pollution and falling navigability.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/hilsa-catches-rivers-dwindle-pollution-rises
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/daily-star-bangladesh
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/fisheries-0
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bangladesh
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/river-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/padma
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/meghna
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/south-asia