Age, Growth and Otolith Microstructure of the Spotted Lanternfish Myctophum punctatum Rafinesque 1810

Marilena Sanfilippo,Teresa Romeo,Francesco Abbate,Franco Andaloro,Danilo Malara,Pierpaolo Consoli,Pietro Battaglia,Maria Giulia Stipa,Francesco Longo

doi:10.3390/jmse9080801

Abstract

This study investigated, for the first time, the age and growth of the spotted lanternfish Myctophum punctatum through an analysis of otolith microstructure. A total of 377 individuals were collected from the Strait of Messina (central Mediterranean Sea), ranging between 20.3 and 73.7 mm of standard length. Their length–weight relationship was estimated, and these outputs indicated an isometric growth, for all specimens and when males and females were analysed separately. The sagittal otoliths were removed from 185 fish, although the microincrement readings were considered valid for only 173 otoliths. Microincrement counts ranged from 32 to 48 (average = 37.6) in the otolith central zone, 30 to 56 (average = 44.3) in the middle zone, and 36 to 384 (average = 165.5) in the external zone. Overall, total microincrements ranged between 106 and 469. Different growth models (Gompertz, von Bertalanffy and logistic models) were considered, to understand which one fit best in describing the growth patterns in M. punctatum. The Gompertz model was then selected as the best-fitting model and its parameters for all individuals were L∞ = 74.79, k = 0.0084 and I = 139.60.

Highlights

Lanternfishes have different life strategies, resulting in various adaptations to deep-sea life and migration patterns. These species display different migratory behaviours, which can be resumed in three main categories [5–7]: (i) strong migrants: species that usually carry out large diel vertical excursions, reaching the epipelagic layer at night; (ii) weak migrants: species performing limited vertical movements in the water column; (iii) non-migrants: species occurring in the same water layers during both daylight and night
The aim of this paper is to investigate the age and growth of the spotted lanternfish Myctophum punctatum, Rafinesque 1810, examining the growth patterns in the otolith microstructure and analysing the length–weight relationship
AccordingAccording to the results of the length–weight relationship,relationship, the growth of punctatum to the results of the length–weight theM.growth of M. puncta is isometric for both sexes

Summary

Introduction

Lanternfishes (Myctophidae) are an important component of the mesopelagic fauna and include more than 250 small pelagic species [1]. Lanternfishes have different life strategies, resulting in various adaptations to deep-sea life and migration patterns. These species display different migratory behaviours, which can be resumed in three main categories [5–7]:. The extent of vertical movements in lanternfishes can be influenced by environmental factors, as demonstrated elsewhere [8], with cyclic migrating patterns in Hygophum spp. from the north and central Atlantic, in relation to the different lunar cycle phases. These differences in migratory behaviour are reflected in the otolith microstructure [8]. Sequences of clear growth increments represent a fast-growth period due to migration in the warmer upper layers; when limited vertical excursions occur, less distinguishable increments are laid down, associated with periods of slow growth in deeper and colder waters

Objectives

Methods

Conclusion