15.1 Mesh Sizes
15.2 Fishing Effort
Analyses have been made, using the best data currently available for hakes in the northern zone of CECAF. Although various methods of assessment have been tried, it must be emphasized that all the analyses are based on the most provisional of data and that the results of the calculations can only be used for preliminary advice to management.
It should also be noted that those analyses that have been done in terms of yield per recruit, do not necessarily give results that can be translated directly into terms of actual yields. Yield per recruit calculations should only be used as a guide to the direction to take (i.e. whether to reduce fishing effort or to increase mesh size). They should not necessarily be used to determine by how much effort or mesh size should be changed to obtain the greatest benefits.
Bearing in mind the tentative nature of the results, the following conclusions have been drawn:
For Moroccan and Spanish vessels fishing in divisions 34.1.1 and 34.1.2, the mesh sizes currently in use are considerably smaller than the recommended mesh size. Enforcement of the recommended mesh size of 70 mm should improve the yield per recruit of hake by more than 100 percent.
For Spanish, Portuguese and USSR vessels, fishing mainly in divisions 34.1.3 and 34.3.1, the mesh sizes in use are close to the recommended mesh size of 70 mm. Enforcement of the recommended mesh size of 70 mm should improve the yield per recruit of hake, although the actual benefits may be quite small.
In Divisions 34.1.1 and 34.1.2, the current level of fishing effort is too high. A reduction in effort should lead to a considerable increase in the yield per recruit of hake.
In divisions 34.1.3 and 34.3.1 further increases in fishing effort are likely to cause the yield per recruit of hakes to decline. The gain in yield per recruit, if fishing effort is reduced, is not likely to be large however.
