Phenological changes in seaweed community structure and the diversity of fish communities in seaweed ecosystems

Abstract

Seaweed communities in coastal areas serve as crucial habitat for many organisms and serve to maintain high levels of biodiversity in coastal ecosystems. However, the loss of these communities because of climate change and increasing levels of marine debris is leading to a decline of biodiversity and remains a significant concern. We studied the occurrence of fish species within seaweed communities formed in the subtidal zone. To observe changes in community structure of fish communities, we conducted the study throughout the year in the coastal waters of Arikawa Bay, Shin-Kamigoto Town, Nagasaki Prefecture, where there are significant seasonal changes in seaweed communities. We recorded species, height, and coverage of seaweeds, and the species and abundance of fish, water temperature, and salinity. We hypothesized that as the species diversity, height, and coverage of seaweed communities increase, the species diversity of and abundance of fish also increases. The seaweed coverage and height peaked during April to June. The number of fish species peaked during July to October, however the abundance decreased during this period; data analysis suggests a strong correlation between seaweed and fish communities. Omnivores and benthic feeders were positively correlated with species coverage and a Procrustes analysis also suggests a strong correlation between seaweed communities and fish communities. Analysis is underway to elucidate the impact of marine debris.