GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN SCIENTIFIC ADVISORY COMMITTEE Sub-Committee on Stock Assessment (SCSA) Working Group on Small Pelagic Species, Izmir, Turkey 22-26 September 2008 THE STATE OF THE SARDINE STOCK IN MOROCCAN MEDITERRANEAN SEA Laboratory of the Fishing Resources Régional Center of INRH in Nador
INTRODUCTION • The small pelagic species are exclusively captured by moroccan purse seiners using the light (lamparo). • This float targets mainly the sardine, the anchovy. Other species are captured like the atlantic horse makerel and the bogue. • The landings of sardine constitute 70 % of total landings of small pelagic species in Moroccan Mediterranean sea. • The following work relate to the evaluation of the state of exploitation of sardine stock by structural models. This evaluation is based on data of capture in nombre by classes of size on the level of principal ports during 2007.
STUDY OF EXPLOITATION Production The main small pelagic species captured : the sardine, the horse makerel and the anchovy. The bogue and sardinelle constitute accessories landings. The sardine is the most captured specie with an annually production of about 14000 tons. The port of Al Hoceima ensure 50% of total sardine in Moroccan Mediterranean sea, followed by other ports in particular Nador and M’diq.
Fig. 1 : Evolution of landings of sardine in Moroccan Mediterranean sea The landings of the in Moroccan Mediterranean sea show a general tendency with the fall. The average production is about 14000 tons.
Float The float of purse seiners is composed by about 150 units, that is 20 % of the coast float operating in maroccan Mediterranean sea. The purse seiners are based in particular in M’diq (35%), Nador (27%) and Al Hoceima (25%). Those boats have modest technical caracteristics (on average, 40 Tonneaux of TJB and 250 cv), reason why their activity is limited in the coast, near the home ports. Actually, the average of exits at sea realised by the purse seiners is estimated at more than 15 000 exits per year.
Fig. 2 : Evolution of fishing effort and the CPUE of the sardine captured in Moroccan Mediterranean sea The analysis of the CPUE show that after the pressure of fishing practiced on the sardine until the year 2003, a certain re-establishment is observed until the year 2004, illustrated by an increase of the CPUE.
Biological sampling The follow-up of the compositions by length ofsardine was carried out mainly in the ports of Al Hoceima, Nador and Ras Kebdana. The sampling is carried out 2 at 3 times per week. Concerning the measurement of size, we take in a simple random way a sample of3 kg of sardine at least. The measurment of sizeare taken with the half centimeter of total lenght. The size frequencies are extrapolated firstly at the sampled boat then cumulated per month in order to extrapolate them at the landings in the ports or in the hole zone. The data used relate to the year 2007.
State of exploitation of sardine stock The landing’s statistics by weight and the fishing effort of purse seiners are obtained monthly from the delegations of the «Office National des Pêches » ONP. The biological data retained for the evaluation of the state of explotation of sardine are those of the year 2007 on the level of the ports of Nador, Ras Kebdana and Al Hoceima. The data of landings and fishing effort come from the 7 ports of the Moroccan Mediteranean sea. With the VIT software (Lleonart and Salat, 2000), an analysis of pseudo-cohorte was realized. The level of exploitation of sardine stock is determined through the analysis of the curve of the yield by recruit and the calculation of biologic reference point Fmax.
Structure by lenght of the stock Figure 1 : Composition by lenght of the sardine in Moroccan Mediteranean sea at 2007. Bimodal distribution : 2 modes (11 &nd 17 cm) The small individuals are observed in the ports of Nador and Ras Kebdana.
State of exploitation of the sardine stock Figure 2 : Vector of fishing mortality by lenght classes The curve of the vector of fishing mortality show that the intensity of fishing is important especially on adult individuals from 16 cm.
Figure 3 : Curve of the biomasse per recruit and the output per recruit The analysis of the curve of production per recruit, show a situation of full-fishing on the sardine stock (Fmax = 1,16).
CONCLUSIONSAND RECOMMENDATIONS -The results show that the fishing is exercised espacially on adult individuals (between 16 and 19 cm).Considerable values of fishing mortality are also observed for small individuals. - The analysis of the yield per recruit indicate a state of full fishing on this resource.
Taking into account this state ofstock and in order to garantee a rational and sustainable exploitation of the resource of sardine, it is recommended : • To maintain the actual pressure of fishing ; • To found a seasonal closing of fishingin the coastal areas which know a massive concentration of the juveniles of sardine ; • To found a biological rest during january (peak of period of spawning at december-january). • To prohibit the fishing of small pelagic species into sensitive areas where is important concentrations of sardine larva(lagoon of Nador and Bay of Al Hoceima).