Ecological risk analysis in marine fish farming: a case study of a seabass (Dicentrarchus labrax) farm located in Moroccan Mediterranean coast

Hassan Nhhala,Benyounes Abdellaoui,Mohamed Id Halla,Imane Nhhala,Hassan Er-Raioui,Abdeljallil Bahida,Azeddine Abrehouch,Housni Chadli,L El Youssfi,S.I Cherkaoui,D.R Salazar,O Seidou,E.S.P Assèdé,A.G Faundez,Y Ouaggajou,A Aghzar

doi:10.1051/e3sconf/202233703003

Abstract

The present study aimed at studying ecological interaction between a fish farm cages located in M’diq bay, in western Moroccan Mediterranean coast, and its local environment. It was carried out in 2013 and 2016 through seabed analysis in terms of organic matter and some nutrients parameters such as Nitrogen and Phosphorus, as well as through monitoring macro-fauna assemblages. The results showed recorded values relatively stable in three years’ interval and have a well-integrated fish farming activity within its ecosystem. Sediment was sandy to sandy shelly types and macro-benthic fauna were composed of six groups, Gastropods, Bivalves, Scaphopoda, Amphipods, Nematoda and Polychaeta. Organic matter and Total Organic Carbon were respectively less than 3.2% and 1.87% and very low comparing with others Mediterranean fish farms sites. Estimation of Nitrogen, Phosphorus and Carbon potential releases of M’diq fish farm gave low data related to its production capacity not exceeding 200 tons by year. Influenced with open sea location and high current state, dispersion pattern of these fish farm discharges seemed to play a key role in keeping lower values. ANOVA analysis showed no significant difference between studied parameters in the five sampling stations comparing with the reference station both on geographical and temporal levels (seasons and years).

Highlights

The development of aquaculture production is related to consumers’ perception, knowing that aquaculture products are registering a higher growth ratio, almost 5.41% per year (3.02 million tons/year) [1]
The main environmental impact is widely thought to be coming from organic matter discharges, resulted from cultured species metabolism and uneaten food
They reported there was no stress for communities associated with Total Organic Carbon (TOC) concentrations 3.5%

Summary

Introduction

The development of aquaculture production is related to consumers’ perception, knowing that aquaculture products are registering a higher growth ratio, almost 5.41% per year (3.02 million tons/year) [1]. The main environmental impact is widely thought to be coming from organic matter discharges, resulted from cultured species metabolism (faeces, pseudofaeces, excretion...) and uneaten food (likely generated by excessive distribution of food or driven away by current). Seabed sediment is characterised by variable granulometry and physico-chemistry patterns depending on geomorphological and hydrodynamic conditions and by holding a multitude of benthic species. For these reasons, it could be considered as a mirror providing information on the local environment health state. Impacts are clearer on the seabed sediment composition [5,6,7,8,9,10,11,12,13]

Methods

Results

Discussion

Conclusion