Reactions from Mika Diop and Philippe Tous

1 The report cited (de L. L'Haridon) doesn't contain the informations given in the Reuters article. The figures concerning the evolution of the number of octopus and the catches volume must have another source, unprecised (Mr. Alasdair Harris, representing Blue Ventures?)

2. The article introduces a confusion between two types of technical fisheries management measures, one being the area closures (the so-called Marine Protected Areas), the other being the temporary closures (also called biological rest periods). In the case described, it is a temporary closure for the octopus fishery only (therefore a measure concerning a mono-specific stock), and has nothing to do with the creation of a Marine Protected Area, where the objective would be to manage a whole variety of species and to protect their habitat.

This technical measure of biological rest is well known in the main octopus producing countries, Morocco and Mauritania, and its impacts have been largely documented. In as much as octopus is a species with a short life cycle and rapid growth, any temporary ban on fishing induces a quick and spectacular rise of its biomass and number of individuals. This translates, when fishing starts again, by high levels of catches, but generally for a short time. Economical benefits are therefore very limited (see the various attempts from Mauritania and Morocco to lenghten the duration of biological rest period, of to install several biological rest periods around the year.)

In Mauritania, for example, biological impacts of the biological rest period have been evaluated and show that this impact:

- is low on octopus catching;

- is positive on the reproducing potential;

- is probably not significative on the future state of stocks (no relation between stocks and recruitment);

- is unknown (but possibly positive) on other species.

In Morocco, the regular increase of the biological rest period length (up to six months of the year) has not been able to halt the diminutions of catches. The fishery had to be completely closed down in 2002.

3. Concerning biodiversity, the study precises that one of the objectives is to concentrate the fishing effort on octopus to spare other resources (herbivorous fish). Their economic value is not precised, but their ecological importance is considered to be high (to fight against eutrophisation and help coral conservation). However, octopus is considered a species whose abundance rises quickly with the degradation of the ecosystem (when octopus juveniles predators and/or competitive species such as Sparids, disappear). The fact that this octopus fishery is booming in the area concerned seems to indicate a local degradation of the eco-system, linked to overfishing or other causes. What is missing in this study is an assessemnt of the whole ecosystem and of the overall fisheries resources to validate one approach rather than another ( in terms of conservation, restoration, economic optimalisation).

4. Another important point, also linked to the octopus biology, is that, like for other short lived species (shrimp in particular), there is an absence of relation between stocks and recruitment and there is also an extreme stock variability with the variation of environmental conditions. Through the concentration of the fishing effort and technical management measures on this sole fishery, there will be high uncertainties in terms of return and global catches from one year to the other (see the case of Senegal).

5. The installation of a biological rest period, in the same way as the setting up of a protected area, rises socio economic problems which are not treated in the report or in the article: what are the alternative activities for the fishermen during the 7 months of biological rest period? Are they fishing for other species? Do they target other species? Are they going into neighbouring fishing areas (competing may be with other fishermen and therefore increasing the fishing pressure)? do they receive financial compensation?

6. In conclusion, we feel this may confuse the fisheries administrators as well as the fishermen implicated in fisheries management. It leads to believe that MPA have "magical" effects, while building the reasoning on one species only and not highlighting that the installation of marine protected areas have complex impacts on eco-systems (attracting big predators and temporarily changing the relations between species, as revealed in the studies on Marine Protected areas of Bamboung in Sénégal and Port Cros in France). Particularly, it's a pity this work is silent about the socio economic impacts of such measures. Unfortunately, a lot remains to be done in terms of how to use MPA for fisheries management.