Characteristics of Ichthyoplankton Communities and Their Relationship With Environmental Factors Above the Ninety East Ridge, Eastern Indian Ocean

Liyan Zhang,Ran Zhang,Longshan Lin,Shigang Liu,Jiali Xiang,Xing Miao,Rui Wang,Puqing Song,Jing Zhang

doi:10.3389/fmars.2021.764859

Abstract

The Ninety East Ridge is a submarine north–south oriented volcanic ridge in the eastern Indian Ocean. Surface-layer ichthyoplankton collected in this area from September to October were identified by combined morphological and molecular (DNA barcoding) techniques, and their species composition, diversity, and abundance, and correlations with environmental variables were described. Collections comprised 109 larvae and 507 eggs, which were identified to 37 taxa in 7 orders, 20 families, and 27 genera, and were dominated by the order Perciformes and species Vinciguerria sp., Oxyporhamphus micropterus, and Decapterus macarellus. Species abundances at each station and of each species were relatively low, suggesting that this area or the time of sampling were not of major importance for fish spawning. Waters above Ninety East Ridge had lower species diversity but higher species richness than waters further offshore. A generalized additive model revealed that high abundance of ichthyoplanktonic taxa occurred in areas with low sea surface height and high sea surface salinity, temperature, and chlorophyll a concentration. Of these, sea surface height was most correlated with ichthyoplankton abundance. We provided baseline data on surface-dwelling ichthyoplankton communities in this area to aid in development of pelagic fishery resources in waters around the Ninety East Ridge.

Highlights

The eastern Indian Ocean is bordered by the Bay of Bengal to the north, Sri Lanka and the Indian Peninsula to the northwest, Sumatra and the Andaman Sea to the east, and the Arabian Sea and South Indian Ocean to the west and south, extending from 65◦E–100◦E, 10◦S–15◦N
37 species of ichthyoplankton were identified in this survey, belonging to 7 orders, 20 families, and genera (Supplementary Table 2), of which 1 species was identified to order, 7 to family, 1 to genus, and to species
Because ichthyoplankton represent an important stage in the life cycles of fish, they are important in assessments of environmental impact, fishery resources, and responses to climate change

Summary

Introduction

The eastern Indian Ocean is bordered by the Bay of Bengal to the north, Sri Lanka and the Indian Peninsula to the northwest, Sumatra and the Andaman Sea to the east, and the Arabian Sea and South Indian Ocean to the west and south, extending from 65◦E–100◦E, 10◦S–15◦N. Except for coastal shelf areas, water depths here exceed 2,000 m; and are up to 5,000 m in the south. This region’s location, climate, and currents contribute to its high biodiversity and rich marine biological resources (Wei et al, 2007). Ninety East Ridge Ichthyoplankton on the biodiversity and biological resources of this area compared with elsewhere in the western Indian Ocean near the eastern coast of Africa (Li et al, 2019). Biological research has focused on bacteria, zooplankton, and phytoplankton (Wang et al, 2016, 2020; Li et al, 2019; Wei et al, 2019)

Methods

Results

Conclusion