Reproduction, energy storage and metabolic requirements in a mesophotic population of the gorgonian Paramuricea macrospina.

Jordi Grinyó,David Díaz,Andrea Gori,Janire Salazar,Josep-Maria Gili,Sandra Mallol,Núria Viladrich,Raquel Castillo,Anabel Muñoz

doi:10.1371/journal.pone.0203308

Abstract

This study examined the sexual reproductive cycle, energy storage and metabolic requirements of a Mediterranean gorgonian in a mesophotic ecosystem (~70 m depth). Paramuricea macrospina resulted to be a gonochoric internal brooding species with a 1:1 population sex ratio. Oogenesis lasted ~12–14 months, whereas spermatogenesis was significantly shorter, only lasting 6 months. Fertilization occurred during late summer (August) and larval release occurred during autumn (September–October). The organic matter and total lipid content showed a slight seasonal variability. Stable isotopic composition remained constant throughout the year, reflecting a general stability in gorgonian food sources. Conversely, the free fatty acid composition varied seasonally, reflecting changes in P. macrospina energetic demands probably related to gametogenesis and larval brooding. The reproductive ecology and biochemical composition of P. macrospina significantly differ from shallow coastal gorgonian species, reflecting the higher environmental stability of deeper environments.

Highlights

In the past few years there has been a substantial increase in the ecological characterization of coral-dominated ecosystems located at 30–150 m depth [1, 2]
Colonies with male sexual products were observed from early spring to late summer (March to August) (Fig 3a), with almost 100% of fertile polyps (Fig 3c)
Oocyte mean diameter progressively increased from mid autumn to late summer (October to August, Table 1; Fig 4) and oocyte number increased from early autumn to late spring (September to June, Table 1; Fig 4)

Summary

Introduction

In the past few years there has been a substantial increase in the ecological characterization of coral-dominated ecosystems located at 30–150 m depth [1, 2]. Light-dependent communities located at ~30–150 m depth are mainly composed of coralline algae growing under reduced light conditions and generating hard-substrates (i.e. coralligenous outcrops and maerl beds, [6]) supporting high-density coral and gorgonian assemblages [7,8,9]. These assemblages are composed of shallow species that extend their distribution to deeper environments [7, 8], as well as by depth-specialist ones with distribution.

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Methods

Results

Discussion

Conclusion