The MEDITS maturity scales as a useful tool for investigating the reproductive traits of key species in the Mediterranean Sea

Abstract

Maturity is one of the most important biological parameters used in stock assessment programmes. Indeed, the macroscopic stage of gonadal development is an essential feature in estimating the maturity ogive and spawning stock biomass. It is also useful for determining the spawning season of a species and for monitoring long-term changes in the spawning cycle as well as for many other research needs related to the biology of fish. Despite the efforts made during the last few decades to standardize maturity stage data among all the researchers, marine biologists continue without a manageable and unique maturity scale to describe the reproductive development of fish gonads. For these reasons, the objectives of this article are 1) to investigate the biological parameters of five selected key species (Mullus barbatus, Galeus melastomus, Etmopterus spinax, Aristeus antennatus, Loligo vulgaris) with different reproductive strategies following the macroscopic maturity scales based on the same univocal criteria adopted in the MEDITS programme and described in this work; and 2) to compare them among some Mediterranean geographical sub-areas (GSAs) involved in the programme. Neither spawning periods nor size at first maturity (SFM50) for the studied species showed particular differences in the investigated GSAs.

Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation

“…Sex was registered and the maturity stage of each individual was determined following the scales proposed for Elasmobranchs by [ 26 , 27 ]. According to the scales, females belonging to viviparous species were classified into eight stages: (1) immature; (2) developing; (3A) capable of reproducing; (3B) early pregnancy; (3C) mid-pregnancy; (3D) late pregnancy; (4A) regressing; (4B) regenerating.…”

“…Sex was registered and the maturity stage of each individual was determined following the scales proposed for Elasmobranchs by [26,27]. According to the scales, females belonging to viviparous species were classified into eight stages: (1) 4) regressing (only for viviparous species) and (4A) resting (only for oviparous species).…”

A Taxonomic Survey of Female Oviducal Glands in Chondrichthyes: A Comparative Overview of Microanatomy in the Two Reproductive Modes

“…Only for the holocephalan Chimaera monstrosa , the anal length (AL, in centimeters) was taken. Maturity stages were established following the scale for oviparous and viviparous elasmobranchs [ 35 ]. According to these scales, oviparous females were classified into six stages on the basis of ovary structure and OG and uterus dimension and texture as follows: stage 1, immature (F1); stage 2, developing (F2); stage 3a, spawning capable (F3A); stage 3b, actively spawning (F3B); stage 4a, regressing (F4A); and stage 4b, regenerating (F4B).…”

Growth and Age Validation of the Thornback Ray (Raja clavata Linnaeus, 1758) in the South Adriatic Sea (Central Mediterranean)

“…Additional samples were obtained from the Mediterranean International Trawl Survey (MEDITS; 2014-2018) (Spedicato et al, 2019) in the South Adriatic Sea, including Albanian and Montenegrin waters (GSA 18). The following data were collected from the collected specimens: total length (TL; in centimeters) to the nearest 0.1 cm, total weight (TW) to the nearest 0.1 g, sex, and maturity stages (AAVV, 2017;Follesa et al, 2019a).…”