Does beach seine fishery permanently alter macroinvertebrate communities and sediment characteristics in the Southern Caspian Sea?

作者：Nemati Haniyeh; Shokri Mohammad Reza^*; Pazooki Jamileh

来源：Marine Ecology-An Evolutionary Perspective, 2015, 36(3): 408-418.

DOI：10.1111/maec.12150

• Beach seine fishery
• benthic communities
• environmental factors
• fishing impact assessment

The impacts of a beach seine fishery on macroinvertebrate communities and sediment characteristics were investigated in the Southwest Caspian Sea. Samples from a single impacted site that was regularly seined were compared with two control sites outside the fishing area. Benthic macroinvertebrates were sampled on four occasions: 6months prior to the opening of the beach seine fishery (Time 1), 1day immediately after the closing of beach seining (Time 2), 1week after closing (Time 3), and 1month after closing (Time 4). No significant differences were detected in total density, Shannon diversity, or evenness of the macroinvertebrate assemblages between impact and control sites. Unlike density, species richness increased significantly immediately after fishery closure at all sites. A significant difference was detected in the number of species between Time 2 and Time 3 at all sites and the number of species was reduced at Time 4 in all sites. Pontogammarids increased by twofold in the impact site 1day immediately after closing beach seine fishery and leveled off toward the end of the closed season. The amplified density of pontogammarids 1day after fishery closing at the impact site might be driven in part by an increase in sediment oxygen content resulting from disturbance of the sea floor. An alternative explanation is that the effect of fish predation on pontogammarids has largely been minimized at the impact site after 6months of continuous fishing activity. No significant changes in the sedimentary organic content and chlorophyll-a between the impact and control sites were observed during the courses of sampling; however, a significant change occurred between the average sedimentary pheopigment content of the control sites and that of the impact site. The conclusion from the present study is that beach seine fishery does not harm to benthic communities. The closed season also seemed to allow recovery to pre-season levels of macroinvertebrate richness and sedimentary chlorophyll-a.

• 出版日期2015-9