Stock assessment of red mullet and hake in the Egyptian Mediterranean Waters Sahar Mehanna Fish Population Dynamics Lab NIOF, Egypt

OutlineOutline   Introduction   Material and Methods   Results 1- Age and growth 2- Growth parameters 3- Mortality and exploitation rates 4- Size at first capture and size at maturity 5- Reference points and management 6- Stock status and challenges 7-Recommendations   Introduction   Material and Methods   Results 1- Age and growth 2- Growth parameters 3- Mortality and exploitation rates 4- Size at first capture and size at maturity 5- Reference points and management 6- Stock status and challenges 7-Recommendations

Introduction

Fishery Resources of Egypt

Egyptian Mediterranean Fisheries

Red Mullet and Hake Fisheries in the Egyptian Mediterranean Red mullet and hake are mainly exploited by trawling The catch of red mullet is composed mainly of two species; Mullus surmuletus and M. barbatus, besides some species of Red Sea origin. The mean annual red mullet landing is 2000 tons ( ) forming about 10% of the total trawl landing while that of hake is 530 ton contributing about 3%.

Objective To estimate the basic parameters required for assessing the exploitation status of red mullet and hake in the Egyptian Mediterranean waters and to define some precautionary reference points for its management.

Material and Methods Fishery statistics Sampling Methods

Results

Trawl fishery The number of licensed vessels ranged between 1100 and 1500 during the period from 1990 to The vessel length varied between 18 and 22 m and its width varied from 4 to 6 m. Each vessel is powered by main engine of 150 to 600 hp but the majority of 250 hp engine. Trawl net is of the Mediterranean type. The fishing trip is about 7 to 10 days and the number of crew is about 6 to 15 persons. The trawl fishery contributed about 33% of the total fish production from Mediterranean.

Age and Growth Hake: 8 yrs old (Length range cm TL) Mullus surmuletus: 5 yrs old ( cm TL) M. barbatus: 3 yrs old (6-24 cmTL) Length-weight relationship W = L M erluccius merluccius : Mullus surmuletus: W = L M. barbatus: W = L

Growth parameters parameterhakeM. surmuletusM. barbatus L∞L∞L∞L∞ K totototo parameterhakeM. surmuletusM. barbatusZ M F E Mortality and exploitation rate

Size at first capture and maturity parameterhakeM. surmuletusM. barbatus LcLcLcLc LmLmLmLm

Yield per recruit hake F c = 0.66 yr -1, F max = 0.25 yr -1 ( 60% decreasing) F c = 0.66 yr -1, F max = 0.4 yr -1

Yield per recruit M. surmuletus F c = 0.73 yr -1, F max = 0.53 yr -1 ( 27% decreasing)

Yield per recruit M. barbatus F c = 0.85 yr -1, F max = 0.61 yr -1 ( 30% decreasing)

Stock status and challenges Over-exploitation due to the high fishing pressure Illegal size nets Illegal harvesting of fish fry Increasing of tourism and industrial expansion which cause damages in coastal ecosystem and pollution Lack of information on fishery status in terms of biological, ecological, social and economic policy Lake of awareness about the importance of fisheries regulations Lack of reliable fisheries statistics.

Recommendations Fishing mortality should be reduced by about 30-50% to maintain stock biomass. Mesh sizes must be regulated and fisheries law should be enforced. Nursery grounds should be identified and protected from illegal fishing. The necessity to work in order to provide a common management information system for the Mediterranean countries. It is necessary to make an accurate data base about our fisheries involving good records for fishery statistics. With the support of regional projects. Fishing mortality should be reduced by about 30-50% to maintain stock biomass. Mesh sizes must be regulated and fisheries law should be enforced. Nursery grounds should be identified and protected from illegal fishing. The necessity to work in order to provide a common management information system for the Mediterranean countries. It is necessary to make an accurate data base about our fisheries involving good records for fishery statistics. With the support of regional projects.

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