|MARINE FISH FARMING|
1. Gilthead beam, sea-bass and meager
The fish breeders farmed in the hatchery of the INRH specialized center in M'diq belong essentially to three species:
• The sea bass (Dicentrarchus labrax);
• The gilthead beam (Sparus aurata); and
• The meager (Argyrosomus regius).
The purpose of breeding the breeders of these fish is to condition their gonadic maturation in order to have spawning eggs in the natural period of their reproduction.
The conditions of breeding allow to intervene only on their food; temperature and salinity being influenced by the surrounding natural environment. The diet provided is based on the use of fresh food (small pelagic fish throughout the year, enriched with cephalopods and crustaceans during the period of gonads maturation).
The year 2016 was considered an exceptional year because it was characterized by:
• a relatively high thermal profile;
• Disturbance of the physiological process of maturation and spawning of farmed species:
o disruption in sea bass spawning(normally short-term spawning, occurring twice between February and March, three to five days with spacing of about one month, and in 2016, sequential (daily) during three and a half months;
o No spawning in seabream;
o Poor quality in meager spawning.
2.Common Two-banded seabream
- The Common two-banded seabream Diplodus vulgaris, a potential species in aquaculture, is very popular with consumers at the local, regional and national levels.
- In view of integrating it as a candidate for the specific diversification of the national marine fish culture, a preliminary experimental trial was conducted for the technical feasibility of its captive breeding under local conditions.
- The results obtained reveal a very good adaptation of the natural fry of Common Two-banded seabream to captive breeding in local conditions and a good acceptance of the "sea bass" type pellet by fry of this species.
MARINE SHELLFISH FARMING
1. The clam
Following the overexploitation of the clam and efforts to preserve this species, INRH in collaboration with Coastal Culture Systems (CCS) has developed a study to control hatchery rearing techniques of this species before to initiate the program of its repopulation in the natural deposits.
The main results of this first study have made it possible to master the clam rearing process and determine the most appropriate diet and feed ration by phase of the rearing process.
2. The mussels
2.1. INRH in collaboration with a private operator (Talhamar) has launched a technical feasibility study of mussel farming in Dakhla Bay, in the southern region.
The objective is to determine the proper breeding process for a better performance of the growth of mussels in breeding.
This first trial of breeding mussels on bouchots gave very satisfactory results with an advantage of the technique of long-lines.
2.2 - The INRH in collaboration with the Atlantic Mussels Company (SAM) carried out a deepwater mussel project in Imiouddar (Agadir Bay), using the ballast saucer system.
This test of deep-sea mussel culture on ballastable saucers in Agadir Bay showed good adaptability of structures to environmental conditions and recorded good zootechnical performance of mussels in deep-water culture (better quality of product).
3.1 In order to control the culture technique and performance of Crassosstrea gigas oysters in the southern region of Morocco, two studies were carried out on two different sites: Dakhla Bay and Cintra Bay and focused on comparing the performance of growth according to two different farming techniques (oyster tables and long-line).
At the Dakhla site, the two breeding structures (tables and Long-lines) gave very satisfactory results. Indeed, the length of time between breeding and reaching commercial size is very short on long-lines (four months) and on the table (nine months).
On the other hand, at Cintra Bay, the speed of growth was very important during the first three months but the breeding site was not stable and favorable (silting, strong agitation, turbidity, etc.).
3.2-In order to improve the performance and the quality of oyster farming in the Oualidia lagoon, a zootechnical feasibility study for the breeding of Pacific cupped oyster suspended in Australian bags was experimented in partnership with the Oyster farms from Saidi’s compagny.
The method of suspension breeding in lockers or Australian bags is to put individuals in plastic bags welded at one end and with an opening system by the other. They have different shapes and thicknesses. Nevertheless, whatever the form, it allows the oysters to move within the bag. Feces, mud and other dirt are removed by the movement of the bag under the action of currents.
The results obtained from this experiment, realized for the first time in Morocco, are very satisfactory (growth rate, mortality rate, quality index ...) in comparison with the traditional technique
4.1 - In order to compare the biological performances (growth and production) of G.gracilis in culture between two sites: one at the lagoon level (lagoon of Oualidia) and the other in the environment (Sidi Rahal foreshore), a study Phytotechnical feasibility of macroalgae cultivation was carried out by INRH teams in 2016.
The cultivation protocol at Oualidia consisted of setting the stakes in a shallow area so as to have all the seaweed growing ropes at 50cm from the surface at low tide. On the other hand, in Sidi Rahal, six dies (rope 12mm in diameter, 100m long and equipped with floats every 10m) are installed perpendicular to the coast. These channels are hung on both sides of the two rock bands by anchors. These channels are reinforced by the addition of counterweight every 20m, in order to compensate for the attraction of floats during high tide. They are also well stretched to always stay 50 cm from the surface at low tide.
In Sidi Rahal and Oualidia, the ropes are sown with clumps of the same strain of seaweed harvested at Sidi Rahal level. Similarly, in both cases, the initial weight of the clumps at the start is 100g / clumps and their length is 25cm.
Cet essai expérimentale de l’agoculture a demontré une bonne adaptation des techniques de culture (corde entre pieux et filières) aux conditions hydrodynamiques des sites d’études et a enregistré des résultats très satisfaisants (taux de croissance, taux de production…) des macroalgues en cultures en milieu marin (Sidi Rahal) par rapport au milieu lagunaire (Oualidia) avec une importante reproduction des algues (gracilaires et laminaires) et fixation de spores au niveau de sidi Rahal en période printanière (mars –avril).
4.2 - Dans le cadre d’élaboration et de mise en place d’une collection algale qui sera disponible pour les programmes de nutrition en aquaculture, une étude d’Identification et d’isolement des microalgues d’intérêt conchylicole a été réalisé par les équipes de recherche de l’INRH dans trois sites : Dakhla (zone Sud), Oualidia (zone Centrale) et M’Diq (zone nord).
This experimental test of Algae farming demonstrated a good adaptation of the culture techniques (rope between piles and dies) to the hydrodynamy conditions of the studied sites and recorded very satisfactory results (growth rate, production rate ...) of the farmed macroalgae in marine environmen (Sidi Rahal) compared to the lagoon environment (Oualidia) with a large reproduction of algae (gracilaria and laminaria) and spore fixation at Sidi Rahal in spring (March-April).
4.3 - In the framework of elaboration and implementation of an algal collection that will be available for aquaculture nutrition programs, a study on Identification and isolation of microalgae of shellfish interest was carried out by INRH experts in three sites: Dakhla (South zone), Oualidia (Central zone) and M'Diq (North zone).
The first results of this first study enabled the identification and isolation of 17 strains of microalgae of aquaculture interest and obtaining the most important strains for hatchery nutrition programs.