April 2012 Preliminary Great Fiji Shark Count results

Preliminary results of the Great Fiji Shark Count, April 2012

In the month of April, 3,693 divers recorded their shark sightings during 855 dives.

The average diver had done 458 dives in Fiji (many were local divemasters), indicating that their observations were very reliable.

During those dives, 12,073 shark sightings, of 11 species, were recorded, plus 5 species of ray, and 2 species of turtles.

Regular shark feeding dives attracted many more sharks, and some species that were not seen on non-feeding dives, but the majority of observations were natural encounters, not feeding dives.

Feeding dives are indicated in Red italics.

Table of commonness of shark species seen on dives in Fiji coastal waters

Most Common Sharks English Name Scientific Latin Name Average number sharks per dive Notes
1 Bull Carcharhinus leucas 1.123866 Shark Feeds predominantly
2 Whitetip Reef Triaenodon obesus 0.881651  
3 Grey Reef Carcharhinus amblyrhynchos 0.599583  
4 Blacktip Reef Carcharhinus melanopterus 0.296363  
5 Tawny Nurse Nebrius ferrugineus 0.152319  
6 Scalloped Hammerhead Sphyrna lewini 0.14561 Schools seen on South Vanua Levu
7 Indo-Pacific Lemon Negaprion acutidens 0.049242 Shark Feeds only
8 Silvertip Carcharhinus albimarginatus 0.033955  
9 Leopard (or Zebra) Stegastoma fasciatum 0.00581  
10 Tiger Galeocerdo cuvier 0.00098 Shark Feeds only
11 Guitarfish Rhynchobatus sp. 0.00051  
12 Great Hammerhead Sphyrna mokarran 0 None seen

Table of number of dives and sharks recorded in each region of Fiji in April 2012

Region of Fiji Number of observations recorded Total Sharks recorded Average number of sharks per dive Number of species found
Beqa Shark Feed 330 8269 25.06 8
Beqa Non Feed 255 348 1.36 5
Coral Coast 327 167 0.51 6
Kadavu 181 139 0.77 5
Lomaiviti 148 340 2.3 5
Mamanucas 841 475 0.56 5
Namena 52 207 3.98 2
Savusavu 322 953 2.96 4
Suva 12 1 0.08 1
Taveuni 769 767 1 5
Vatu-i-Ra Passage 455 407 0.89 4
Grand Total 3693 12073

Maps showing number of sharks and shark species in each region

Shark numbers are expressed as the average number of sharks seen on a single dive, to discount multiple sightings by more than one diver per dive.

Apart from the regular feeding dives, the most sharks were seen in Beqa, Namena, Savusavu and Lomaiviti, but a wider variety of species was found in the Mamanuca Islands, the Coral Coast of Viti Levu, Beqa, Kadavu and Taveuni.

 

Mapped average number of sharks per dive
Mapped average number of sharks per dive

 

Mapped number of species
Mapped number of species

 

Graphs showing numbers of sharks and shark species seen in each region(Shark feeding dives removed)

Shark numbers graph
Shark numbers graph

Apart from at feeding dives, the highest average shark numbers per dive were seen in Namena and Savusavu, where schooling Scalloped Hammerheads and other pelagic species are regularly seen, followed by the Lomaiviti area, Beqa (non-feeding) and Taveuni.

Shark species graph
Shark species graph

The largest variety of species (apart from the feeding dives) was found on the Coral Coast, where Tawny Nurse and Leopard Sharks are regularly seen in the passages, and Guitar fish occasionally.

Most other regions featured 4 or 5 species most of the time, with Suva and Namena recording a lower number of species.

Table of average number of shark species seen per dive in each region Special sightings

  Number of divers White-tip Reef Silvertip Tawny Nurse Indo-Pac Lemon Leopard/
Zebra
Blacktip Reef Grey Reef Bull Tiger Scalloped Hammerhead Great Hammerhead Guitarfish
Region Beqa Shark Feed 330 4.094 0.345 1.779 0.591 0.018 2.767 2.367 13.097 0.012 0 0 0
Beqa Non Feed 255 0.557 0 0 0 0 0.306 0.102 0.388 0 0 0 0
Coral Coast 327 0.309 0.024 0.024 0 0 0.122 0.024 0 0 0 0 0.006
Kadavu 181 0.503 0.033 0.011 0 0.028 0 0.193 0 0 0 0 0
Lomaiviti 148 1.074 0 0 0 0.014 0.108 1 0 0 0.101 0 0
Mamanucas 841 0.429 0 0.008 0 0 0.108 0.018 0.001 0 0 0 0
Namena 52 1.192 0 0 0 0 0 2.788 0 0 0 0 0
Savusavu 322 0.752 0 0 0 0 0.075 0.488 0 0 1.646 0 0
Suva 12 0.083 0 0 0 0 0 0 0 0 0 0 0
Taveuni 769 0.921 0 0.005 0 0.01 0.009 0.052 0 0 0 0 0
Vatu-i-Ra Passage 455 0.666 0.004 0 0 0 0.062 0.163 0 0 0 0 0
Fiji Average Including feeding 3693 0.882 0.034 0.152 0.049 0.006 0.296 0.6 1.124 0.001 0.146 0 0.001
Without feeding 3363 0.59 0.006 0.004 0 0.005 0.072 0.439 0.035 0 0.159 0 0.001
  • Schooling Scalloped Hammerheads were reported from the Savusavu/ South Vanua Levu reefs.
  • Guitarfish have only been reported from the Coral Coast of Viti Levu.
  • Lemon Sharks and Tiger Sharks have only been seen on shark feeding dives.
  • Bull Sharks are occasionally seen on other reefs, but predominantly on feeding dives