1. Indian Ocean: tropical tuna catches increasing rapidly over the last two decades
Patudo
Listao
Albacore

2. Effective fishing effort increasing rapidly over the last two decades
Nominal
Purse seine effort
Longline effort

3. Longliners: fishing effort and area exploited increasing since 1952

4. Purse seiners: nominal effort stable, but permanent and marked increase in efficiency from technological developments
Biomass stocks
Rendements
Average yield of vessels in the area from 1984 to 1999 are stable following an initial rise
While the stock biomass is believed to be dropping fast due to the rise in exploitation rate

5. Critical lack of stock assessment in the IOTC area
Stock assessment missing or doubtful for the three species of tropical tunas
Principal biological parameters, essential for stock assessment models, are still unknown
For the yellowfin and bigeye tunas, unquantified but recognized risks of overfishing, arising from the increased fishing effort of both purse seines and longlines
For bigeye, risk of recruitment overfishing, biologically dangerous situation
Interactions between fisheries not quantified

6. Yellowfin - Thunnus albacares
Annual landings falling  suggests possible overfishing
Catches levelled off 
Falling rate of increase of CPUE 
Falling mean weight of fish in free schools

7. Bigeye - Thunnus obesus
Catches rising too fast in recent years: juveniles (purse seine) and adults (longline)
A scenario that could lead to serious overfishing (long lived species)
Catches may now be over MSY
Scientists recommend limiting catches of juveniles
MSY?

8. Skipjack - Katsuwonus pelamis
Stock probably in good shape: no indications of overfishing
But two delicate problems:
=>excessive number of FADs used by purse seine fishery – possible negative biological effects still unknown
=>danger of interactions between purse seiners and Maldives artisanal fisheries (pole-and-line)

9. An excessive number of fish aggregating devices (several thousand now
An excessive number of fish aggregating devices (several thousand now?) could be an ecological trap and:
Change natural biological cycles of tunas, migrations in particular,
Increase the natural mortality of juveniles,
Increase fishing mortality and discards, in particular of yellowfin and bigeye juveniles but also of associated species,
Reduce the number of multi-species free schools.