Loading...
 

Fish sampling technique for LTT

Access the data

An interannual survey

The fish survey is driven by The Team since 1982 ont the fringing reef of Tiahura, the barrier reef and the outer slope down to 12m depth. Fish are counted four times at the same station. The four countings are realised one after another at the same station and so can be considered as temporal replicates. This database begins in 1987 with fish counting twice a year, respectively around March and September between 9am and 11am around the first moon quarter in the lagoon.
Fish diets are the same as in the ATPP program:
1. herbivores
2. omnivores
3. invertebrate eaters
4. diurnal carnivores
5. nocturnal carnivores
6. piscivores
7. zooplanktivores

Literature references: Galzin, R. (1985). Ecologie des poissons recifaux de Polynésie française. Thèse de Doctorat es Sciences, Université des Sciences et Techniques du Languedoc

 

Sampling by geomorphological zones

Outer slope (-12m, GPS DMS:17°28'58,2"S 149°53'58,0"W)
50 m x 2 (100m²) transects, parallel to the reef crest
The whole transects is scanned regularly for big individuals and / or very mobile species. For small individuals or more territorial species, the transect is divided into sub-sections of 5m within which only the individuals that are present are identified. A second pass focuses on the specie Ctenochaetus striatus, very abundant in the transects.

Barrier Reef (GPS DMS: 17°29'05,1"S 149°53'58,9W)
50 m x 2 (100 m²) transect, parallel to the reef crest
All the fish are counted in one pass.

Fringing Reef (GPS DMS: 17°29'20,2"S 149°53'58,3"W)
50 m x 2 (100m²) transect, parallel to the coastline
The first and third passage (pushed by the current) are dedicated to "Thalassoma hardwicke" and "Ctenochaetus striatus". The fourth and second pass (against the current) are dedicated to the "Stegastes nigricans" and all the ichthyological fauna except the three previously cited species.

Locations
Position of the 3 permanent quadrats for fish census set up during R. Galzin's PhD thesis (1985) on the fringing reef, the barrier reef and the outer slope of Tiahura.

Calendar

1)  2017-08-21
Cook Islands
2)  2017-08-28
Série Galzin
3)  2017-09-11
Samoa
4)  2017-10-16
Tonga