Original scientific paper

Behavior of some growth performance indexes for exploited Mediterranean hake

Sergio RAGONESE ; Institute for the Coastal Marine Environment, IAMC-CNR, Mazara del Vallo TP, Italy
Sergio VITALE ; Institute for the Coastal Marine Environment, IAMC-CNR, Mazara del Vallo TP, Italy
Salvatore MAZZOLA ; Institute for the Coastal Marine Environment, IAMC-CNR, Mazara del Vallo TP, Italy
Elena PAGLIARINO ; Institute for Agro‑environmental Biology and Forestry, IBAF-CNR, Monterotondo Scalo RM, Italy
Marco L. BIANCHINI ; Institute for Agro‑environmental Biology and Forestry, IBAF-CNR, Monterotondo Scalo RM, Italy

Abstract

In this paper, some life‑history estimates concerning the females of the Mediterranean hake Merluccius merluccius (L., 1758), i.e. the parameters of the von Bertalanffy growth function (L∞, K, and t0), the maximum-ever lengths (Lmax-e), and the lengths at full maturity (Lmst) were gathered from the pertinent literature and used to derive 5 growth performance indexes (K, φ’, RL=Lmst/ L∞, t50% and ω). The original datasets (n= 70) and the corresponding growth performance indexes were organized and analyzed by various geographical units (GFCM’s geographical sub‑area, GSA; GFCM’s statistical division, GD; and biological province, BP). The parameter distribution resulted to be normal only for the growth performance indexes K and RL; a significant relationship correlation was detected between K and t50%, between φ’ and ω, and between K and ω. The examination of the available historical data showed a scattered and unbalanced geographical distribution by GSA (e.g. 13 of 20 GSAs had less than 5 datasets each), a variability which was higher intra‑GSA than inter‑GSAs (as evidenced by the box‑plots) and no clear geographical trend. GD and BP presented similar patterns, with significant geographical effects only in the RL. Present results suggest that, even if geographical effects are expected, they are obscured by the uncertainty of the original parameters, especially those related to the von Bertalanffy growth function (vBGF). Consequently, growth performance indexes should be used (and interpreted) with caution.

Keywords

Merluccius merluccius; Mediterranean hake; growth performance index; geographical partition; GSA; Mediterranean Sea

Hrčak ID:

89755

URI

https://hrcak.srce.hr/89755

Publication date:

30.6.2012.

Article data in other languages: croatian

Visits: 2.640 *