Nutritional condition of two coastal rocky fishes and the potential role of a marine protected area

Abstract

Knowledge of the nutritional conditions of coastal commercial fish populations is key to understanding stock health status, and is essential when making reasonable exploitation and management plans. Here, we present the first results on the condition and feeding preferences of two coastal fish species, Diplodus sargus (Linnaeus, 1758) and Pagellus erythrinus (Linnaeus, 1758). Using stable isotope and biochemical analyses, we tested the potential effects of a marine protected area (MPA) and the occurrence of a dramatic coastal storm on the condition and quality of nutrition. The results suggest that both condition (lipids) and nutrition quality (fatty acids, FAs) in P. erythrinus and D. sargus depend upon on food availability in the area in which they were captured. Pagellus erythrinus individuals inside the MPA stored higher quantities of lipids [46.73 AE 19.00 lg lipidÁmg organic matter (OM) À1 ] than those outside the MPA (15.63 AE 5.30 lg lipidÁmg OM À1 ) only before the storm. Diplodus sargus showed different FA signatures inside and outside the MPA before and after the storm. These results suggest that D. sargus increased their quality of nutrition inside (16.62 AE 3.17 lg FAÁmg OM À1 ) versus outside (7.88 AE 2.36 lg FAÁmg OM À1 ) the MPA, owing to increased food diversity and availability. Conversely, P. erythrinus did not show differences in nutritional quality inside (18.12 AE 1.13 lg FAÁmg OM À1 ) or outside (18.81 AE 1.42 lg FAÁmg OM À1 ) the MPA, possibly because of the increase in ingestion not affecting the studied parameters. In P. erythrinus, the FA concentration decreased after the storm, but in D. sargus, a change in lipid composition was observed. These results suggest that P. erythrinus appears to be more impacted by food quality (different saturated and unsaturated FAs) than D. sargus, owing to a more restrictive diet. We hypothesize that the observed differences between inside and outside the MPA are not only related to the degree of protection, but also to the feeding preferences and behaviour of both fishes.

Parasite communities of the white seabream Diplodus sargus sargus in the marine protected area of Medes Islands, north‐west Mediterranean Sea

“…The protection measures in the NTZ guarantee the preservation of these habitats and their fauna and potentially increase nutrition quality (D'Anna et al ., ; Gordoa & Molí, ). The latter aspect is confirmed by two studies analysing the overall and nutritional condition of D. sargus from two western Mediterranean reserves (Lloret & Planes, ; Viladrich et al ., ). It should also be mentioned that the specimens of D. sargus sargus analysed by Viladrich et al .…”

“…It should also be mentioned that the specimens of D. sargus sargus analysed by Viladrich et al . () are partially included in the present study.…”

RNA/DNA and derived condition indices for anchovy and hake larvae as relevant information for comprehensive fisheries management

“…Previous studies have shown that the application of MPAs has positively influenced the nutritional condition of fish species of commercial interest (Viladrich et al 2016). The RD index and its derivatives are highly sensitive, which has made it possible to map the larval condition and establish favourable areas in relation to the NPFS.…”

“…The monitoring of the larval state in situ over time could be a useful tool for determining favourable breeding areas for the species and for developing a time series to assess the effects of climate change in these areas. Detecting these favourable areas and periods for larval survival makes a valuable contribution to the comprehensive management of a population subjected to fishing exploitation (Viladrich et al 2016).…”

Effects of outdoor cultures on the growth and lipid production of Phaeodactylum tricornutum using closed photobioreactors

“…Fatty acids (FAs) samples were analyzed following the methodology described by Rossi and Fiorillo (2010), Rossi et al (2006b), and Viladrich et al (2015). Five samples of approximately 10 mg (±0.1 mg) of dried biomass from the different experiments were dissolved in dichlorolmethane:methanol (3:1); the FAs were analyzed with a splitless injection technique using gas chromatography analysis performed with an instrument (Agilent Technologies 7820A GC) equipped with a DB-5 ms Agilent column (60 m length, 0.25 mm internal diameter and 0.25 lm phase thickness).…”