Abstract

<p>The diets of fishes are used to study trophic interactions in aquatic communities and are important tools for fisheries management. The diet of Parachelon grandisquamis from St. Nicholas River, Bayelsa State, Nigeria was studied for one year (November 2020 to October 2021) using the stomach contents. Fish were caught from the full stretch of the river and identified to species level using keys and descriptions. A total of two hundred and sixteen (216) P. grandisquamis stomachs were studied. Stomachs were excised, preserved and the contents analyzed using the numerical, frequency of occurrence methods as well as the index of food significance. The results showed that the food of P. grandisquamis as indicated by the stomach contents were plant parts &gt; diatoms algae &gt; crustaceans &gt; fish parts &gt; annelids; other items included sand grains and detritus. For % number of food items, plant parts (55.91%) showed the highest numbers followed by diatoms (20.57%) especially Fragillaris sp (n=439), algae (16.92%), crustaceans (3.45%), fish parts (2.02) and the least were annelids (1.13%). For % frequency of occurrence detritus (27.00%) was recorded as the most frequently occurred followed by sand (25.00%), plant parts (19.63%), crustaceans (9.88%), diatom (7.63%), algae (7.13%), fish parts (2.13) and annelids (1.63%). The result of the % index of significance showed that the primary food items (i.e., IFS ≥ 3%) of P. grandisquamis are plant parts (77.55%), followed by diatoms (11.095) and algae (8.52%). Crustaceans (2.41%), fish parts (0.30%) and annelids (0.13%) are secondary food items (i.e., IFS ≥ 0.1 to &lt; 3 %). Others such as sand grains and detritus are regarded as incidental food items (i.e., IFS ≤ 0.1%). There was no seasonal variation in the type of the food items consumed however, the total number of food items consumed was greater in the dry season (3483) compared to the wet season (2457) with plant parts &gt; diatoms &gt; algae &gt; crustaceans &gt; fish parts &gt; annelids in both seasons. In conclusion, P. grandisquamis from St. Nicholas River is an omnivorous and opportunistic feeder with preference for plant-based materials.</p>