Measuring the secondary production of Acartia pacifica in the estuaries water of Arvandrud river- Khuzestan Province

The purpose of this study was to examine the secondary production of the dominant species of the Acartiidae family in the Arvandrud estuary. Specimens were sampled monthly for one year, at eight stations from December 2018 to November 2019. Sampling was conducted with a 300 µm mesh size plankton net and a 45-cm-diameter mouth. Environmental parameters such as temperature, salinity, dissolved oxygen, depth, and water turbidity were measured monthly. Five species belonging to the Acartiidae family were identified, including Acartia pcifica, A. fossae, A. danae, A. faoenis, and A. ambionesis. Due to the highest percentage of frequency for A. pacifica (107± 40 ind.m-3), and because of its presence in most months and stations, it was known as a dominant species. The measurement of the total length of A. pacifica showed that the length of this species along the Arvandrud River has relatively similar values. The average length measured in station 2 has the highest value (0.122±0.016) of the total length. Biomass changes in this species showed the highest amount of biomass in spring (1.24 mg of carbon per cubic meter) and the lowest amount in autumn (0.46 grams of carbon per cubic meter). Secondary production of dominant species was obtained at 0.99 mg C.day-1 during the summer and at 0.25 mg C.day-1 in the autumn. According to the Pearson correlation, there was no significant correlation between identified species abundance and larval abundance at different stations.