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2. SURVEY OBSERVATIONS

2.1 Mahé

Anse à la Mouche

This is a well protected bay and apparently seldom experiences high waves or strong winds during either the southeast or northwest monsoons.

Oysters were quite numerous along a wall built to contain the sides of a small stream which enters the bay at about its centre. This wall was built in 1948 and according to the builder, Mr. Jumeau, it was covered by an extremely heavy spat settlement one year later. Oysters have continued to grow since then but he does not recall the time of year the spatfall occurs.

Oysters were also found in numbers along sea walls and tidal rocks on either side of the bay and could be observed attached to other rocks offshore in the shallow waters of the bay.

This bay appears to have the best potential for seed collection and raft culture and it is suggested the initial work should be carried out here.

There is a supply of native adult oyster for seed production and spatfall seems to be fairly heavy. It will be necessary to follow the gonad development of the native oysters carefully in order to determine the approach of the spawning period.

The water is believed to be rich in plankton. This is supported by the large schools of mackerel and sardine which come into the bay year round to feed. Several of these schools were observed during this survey.

This bay is well protected for raft and longline culture although it is open to a direct east wind. However the reef at the north end of the bay would afford protection from easterly winds. It is readily accessible by road and convenient to an agricultural experimental station. There is a small building here which could serve as a temporary office/laboratory.

Anse Boileau

Oysters are found along the south arm of the bay, growing on the rocks at the edge of the bay. This bay is another possible site and experiments should be carried out here; it would appear well suited for longline and rack culture experiments.

Cap Terney

This is another protected bay but not as accessible as Anse à la Mouche.

On the rocks at tidal level oysters were found. Many young oysters were found but not in large numbers. These ranged in size from ¼ in ( 6 mm) to ¾ in (19 mm) and could have been a set from 1971. Most of the adult oysters were surrounded by 15 to 20 oyster spat. Spat collectors should be placed here at the appropriate time during the spawning season.

This bay also would appear to be suitable for longline and raft culture, however as it is more or less open, during the northwest monsoon the rafts would probably have to be moved to a more protected area.

Port Glaud

This is another well protected bay. Oysters were found on the rocks at tidal level but were not as numerous as Cap Terney.

The bay is another possible site for raft and longline culture and might be suitable as a shelter for the rafts when weather conditions become too rough at Cap Terney.

Grand Anse

This is not so well protected as the previous bays but could be utilized for longline culture and during the northeast monsoon season for raft culture. A small stream enters the south end of the bay and oysters were found growing on the rocks at the mouth of the stream.

Baie Lazare

No oysters were observed although this bay is well protected. There is a possibility that Baie Lazare and the following two listed here might be used as a growing or fattening area.

Anse Royal

No oysters were observed here. It might be used as a growing area during suitable weather.

Anse aux Pins

No oysters were observed.

Between the airport and Victoria there are oysters in isolated spots (Pt. Cascade, Brilliant Point) but nowhere in any numbers.

Bel Ombre

It was not possible to inspect this area but oysters are reported to be growing here in fair numbers in the tidal rocks.

Prasline

In general there were few oysters found on this island although it offers several well protected areas for raft and longline as well as rock culture. At one time oysters apparently were quite numerous and grew well but in recent years fewer oysters are found growing on the rocks and most of these are dead or dying.

Cote d'Ore Beach

Attempts to raise oysters were started here in 1940 by Mr. André Possesion, one of the local residents who had lived in Brittany and was familiar with oyster culture. Oysters were collected from shore-side rocks and placed around a small rocky island offshore. These spawned and grew in large numbers and spread all over the shore and the island rocks. Two years ago however the large oysters (which took about five years to reach 3½ in (90 mm) in size began to die off. Since that time most of the others have also died. The cause of this is not known but it is suspected that there is a lack of sufficient food in the water. As they had all died fairly recently there is a possibility that their death could be due to other factors.

The other oysters on Prasline are also reported to be dying but the cause is unknown.

Although several other areas on Prasline were inspected, only a few live oysters were found, but many recently dead shells could be observed attached to the rocks.

Due to the apparent die-off of the local oysters it would not be advisable to initiate oyster culture on Prasline at this time. It was thought that arrangements should be made for periodic checks and at a later date a project should be initiated to investigate the causes of the mortalities and to try to revive the area for future oyster culture.

Curieuse and La Digue

Curieuse and La Digue were also visited but inspection was limited; prospects were not encouraging however and further examination was judged unwarranted.

It was recommended that at this time no attempts be extended to develop oyster culture on these islands.

As a result of this survey it was recommended that operations be concentrated on Mahé at the following locations:

  1. Anse à la Mouche
  2. Cap Terney
  3. Port Glaud
  4. Grand Anse

Provision should be made to transport rafts, trays etc. to protected areas on the eastern side of Mahé during the northwest monsoon if necessary.

Anse à la Mouche was recommended as the centre of operation and site of initial experimental work. The majority of raft culture for both local and imported species could be conducted here as well as initial spat collecting trials. Grand Anse, Cap Terney and Port Glaud should be used for experimental growing areas and if convenient Cap Terney for collecting spat.

It will be noted that the recommended sites for the initial experimental work are all on the west side of Mahé. The expert was to look for other areas in the eastern side of the inland in case there might be suitable places which were missed by this rather limited survey. The eastern side of Mahé might offer places which could be utilized as fattening or growing areas and for shelter, where the rafts could be moved for protection during the monsoon season.


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