Implementation of Existing International Legal Instruments for Conservation and Sustainable Uses of Marine Biodiversity in Areas beyond National Jurisdiction: A Case Study of the OSPAR Convention
The states of the world face the new challenge of attempting to prevent the global loss of marine biodiversity by protecting the 64% of the surface area of the oceans that lies beyond national jurisdiction. With this aim, various regional agreements have been negotiated to commit states to set up representative networks of marine protected areas (MPAs). The aim of this note is to explain how it was possible to designate six MPAs in the high sea under the OSPAR Convention and some of the challenges this process raised.
Securing a Sustainable Future for the Oceans Beyond National Jurisdiction: The Legal Basis for an Integrated Cross-Sectoral Regime for High Seas Governance for the 21st Century
The legal regime for the high seas is fragmented both sectorally and geographically and is incomplete. Governance, regulatory, substantive and implementational gaps in the legal framework serve to limit the effectiveness of the high seas regime in securing a sustainable future for the conservation and use of the high seas environment and its resources. A global approach to further developing the high seas regime based on the concept of international public trusteeship for the oceans beyond national jurisdiction could foster environmentally responsible use of the high seas and its resources and ensure the application of modern conservation principles and management tools to human activities on the high seas. In view of escalating threats to the oceans from existing and emerging uses and from the impacts of climate change, transformation to a legal regime better suited to integrated, cross-sectoral management and preservation of vital ocean ecosystem services and resilience may no longer be a luxury, but rather a necessity.
Lake Muzahi, Rwanda: limnological features and phytoplankton production
Lake Muhazi, a small lake of Rwanda (East Africa) was studied from 1986 to 1990. A dramatic decrease of the catch of Oreochromis niloticus (350 T y−1 in the fifties vs 30 T y−1 in 1982) suggested a loss of productivity or overfishing. In the same period, other ecological changes occurred: the submerged macrophytes regressed and there was a decrease in Secchi depth (0.65 m in 1987 vs 1.5 m in the fifties). Compared to other lakes of the same area, the plankton production seemed low. The results of the present study characterize lake Muhazi as a shallow lake with a rather unstable diurnal stratification and with slight differences in mixing regime between its eastern, deepest part and its western, shallowest part. Secchi disk depth does not vary seasonally to a large extent. The water has a rather high mineral content (conductivity of about 500 µS cm−1 at 25 °C) and low concentrations of dissolved N and P, except in the hypolimnion, where NHinf4sup+-N can be high.Two species, Microcystis aeruginosa and Ceratium hirundinella, account for most of the phytoplankton biomass, which is about 50–80 mg chlorophyll a m−2 in the euphotic zone, usually with little seasonal variation. Daily gross production estimates amount to about 6 to 9.5 g O2 m−2 d−1 with a significant difference between the two parts of the lake. Data on C:N and C:P ratio in the phytoplankton suggest that some N deficiency might occur in the eastern part. Moreover, the Zm:Zc ratio could also lead to rather low net production rates (0.21–0.25 d−1 for a mixed layer of 4 m)In conclusion, the primary production of lake Muhazi is medium for African lakes and the hypothesis that decreased planktonic production could account for a reduced fish production should be discarded. Whereas the present yield of the fishery is only 20 kg ha−1 y−1, the yield estimated from primary production ranges between 46 and 64 kg ha−1 y−1. This could be reached through proper management. Finally, some hypotheses are given to explain the ecological changes which occurred in the lake.