Grouper sizes in areas with or without fishing
Plectropomus laevis, P. aerolatus, and P. leopardus are all included since all are equally targeted by LFT and underwater identification is difficult.
Groupers are not just caught by the Live fish trade but specific species and specific sizes are initially targeted.
As the graph shows, protected and lightly fished reefs not only have many more fish but also have the largest size individuals. These large individuals are very important because they are all males. Groupers change sex from female to male at a size of 50-55 cm (large/x large boundary on the graph.
Click here to see areas surveyed.
ON THE FISHED REEFS IN SABAH, THERE ARE NO MALE FISH!
This situation is repeated in the Philippines where in 1999 and 2000, the fisheries department survey showed no fish over 45 cm. All the fish in the Philippines which are caught by fishers are female. Without the large male fish, the fish populations in both Sabah and the Philippines cannot reproduce.
The national parks and other protected areas such as Pulau Layang Layang are very important in protecting the only breeding fish in the region.
The humphead wrasse has been studied in detail on Pulau Layang Layang in an effort to understand reproduction and population dynamics.
Coral reef survey to 2005 menu
Survey sites – Ecotourism - Fisheries issues – Fisheries issues E Malaysia – Pelagic fisheries – Non reef fisheries
- Blast fishing – Frequency – Regulations – Economics – Effects of bombs on diversity – effects of bombs on reef structure
Cyanide fishing – Cyanide fishing Map -Regional threats – Market forces - Social impacts of cyanide – Environmental costs of Cyanide -
Reef fish population decline – Coral trout & Leopard Groupers – Large grouper size change with fishing - Sweetlips – Snappers – small groupers – Sex change & threatened species -
Humphead wrasse & Live fish trade -location map– Regionally extinct – HHW populations – Spawning & Feeding – ID of individuals
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the results are opposite of what I’d expect between protected and lightly fished reefs