Part III - Discussion:
In the face of global change, it is a major challenge of our time to understand the capacity of the tropical
marine system to meet human needs without compromising opportunities for future generations. Our current problem deals with
the understanding the effects of human induced changes in relation to changes brought on by natural causes on both a global
and a local level.
Fishery Management supported by scientific investigation: Most biological issues of concern regard over-harvesting, harmful methods of harvesting and the continual degradation of important fish habitats. To properly understand the degrading effects of excess fishing practices, it is advisable even at this stage to investigate:
In addition, remote satellite sensing of phytoplankton should be done in order to quantify the level of primary production. Upper trophic levels, such as the grazing of zooplankton, and in turn secondary and tertiary consumer levels should be screened to obtain detailed data about total biomass productivity. Further detailed scientific studies should help to shed light onto the nutritional preferences that larval fish prefer and the amounts eaten by fish during one day, which ultimately, will make fishery management sustainable as it will be possible to determine flexible quotas for the amount of fauna that can be harvested without damaging the trophic relationships.
Acanthaster planci (Acanthasteridae) - a notorious nocturnal predator of scleractinian (branching) corals (150kB)
A cosmopolitan herbivore Eretmochelys imbricata (Chelonidae) (120kB)
Two Scorpaenopsis diabolus (Scorpenidae) on an eroded Lobophyllia sp. (185kB)
Apart from the direct nutritional benefits on an intact marine habitat, there are some other aspects of
Lobophyllia sp.(Mussidae) inbetween Cyphastrea sp. (Faviidae) left and Acanthastrea (Mussidae) right (160kB)
Species Intrusion: It is also advisable, to monitor the increasing boat traffic - especially that of
large container vessels. The remote location as the Seychelles in particular should address the topic of ballast water by
studying sources of paralytic shellfish toxins which international ships may introduce to their marine environment.
Plankton loaded waters attract the pelagic cosmopolitan Rhincodon typus (Rhincodontidae) (95kB)
Changes in species composition: It is essential to reveal the role and significance of soft corals
on coral reefs especially at this stage, as many reef sites of the Seychelles are still suffering from the impacts of the
1998 ENSO. It was observed that soft corals, part of a normal coral reefs, in some circumstances are suspected of being an
indicator of reef degradation. Thus, it is essential to understand nutritional requirements of soft corals, their distribution, dispersal
and how often they are found in disturbed areas before one can judge their usefulness as a symptom of poor reef health. Likewise
important are patterns and causes of algal distributions on the reef in order to distinguish natural differences between reefs from
changes in the reef benthos, which may be caused by human activities on the reef or adjacent land.
Dendronephyta sp. (Nephtheidae / Octocorallia) have a prickly appearance due to sharp supporting bundles of sclerites (150kB)
ENSO: Although there are no clear records of mass-bleaching events prior to 1979, it is possible
that such events could be rare but recurrent phenomena that reefs have recovered from in the past. However, the extent of
coral bleaching observed during recent ENSO provides a clear indication of the wider long-term impacts of rising sea surface
temperatures. Although such events are largely driven by ENSO at the present time, most climate models predict that the
threshold temperatures which currently drive mass-bleaching events will be reached on an annual basis in 30-50 years.
Small colony of Leptoseris sp. (Agariciidae) (160kB)
And finally, the snorkelling and diving public: Even though, at the current level, it is not yet a
pressing issue, dive tourism is and more so in the future will be an important source of income for the locals. As there are
both land bases and a live aboard which operates into the furthest reaches of the Seychelles archipelago it is essential
to manage this growing industry properly. Dive boat anchors cause damage to reefs, smashing corals when they are thrown
overboard. Providing floats or buoys for boats for tying up instead of anchoring can eliminate this impact.
Young Favia sp. (Faviidae) and larger Porites sp. (Poritidae) above (170kB)
Fabricius K.; Alderslade P. 2001; Soft Corals and Sea Fans; A comprehensive guide to the tropical
shallow water genera of the central-west Pacific, the Indian Ocean and the Red Sea;
AIMS; Townsville - AUS
Gosliner T.M., Behrens D.W., Williams G.C.; 1996; Coral Reef Animals of the Indo-Pacific;
Sea Challengers; California - USA.
March L., Slack-Smith S.; 1986; Sea Stingers; Western Australian Museum, Perth - AUS
Mojetta A.; Ghisotti A.; 1998; Pesci e Coralli del Mar Rosso; Arnoldo Mondadori Editore Spa,
Milan - ITA
Pears V.&J.; Buchsbaum M. & R.; 1986; Living Invertebrates; Boxwood Publishers,
Los Angeles , CA - USA.
Spalding M.; Ravilious C.; Green E.P.; 2001; World Atlas of Coral Reefs; UNEP World Conservation
Monitoring Centre; Cambridge - UK
Veron J.E.N.; 2000; Corals of the World; Australian Institute of Marine Science; Townsville - AUS.
Wood E.M.; 1983; Corals of the World; TFH Publications Inc Ltd - USA
Recent AIMS Report sheets: Human Impacts on Coastal Marine Ecology; Marine Biogeochemistry of
Contaminants; Marine Bioproducts; Monitoring Change in Tropical Marine Biota;
Predicting the Coastal Marine Environment; Supporting Tropical Fisheries;
Sustaining Coral Reefs;
Caroline Cort 1996; One World - Anchoring and Diving on coral reefs;
Australian Broadcasting Corporation; Melbourne - AUS
ENSO - (El Niño-Southern Oscillation):
State of the world reefs - Bigot L., Charpy L., Maharavo J., Rabi A.F., Paupiah N.,
Aumeeruddy R., Viledieu C., Lieutaud A. 2000; AIMS, Townsville - AUS
State of the reefs around Mahé island
TBL (Tissue Bleaching):