Successful Sodwana fish tagging expedition
The expedition's purpose was to compare fishing in sanctuaries with exploited areas
TO encourage anglers to respect the ‘no-take’ fishing zones and to report tagged fish when caught, a group of anglers, including fish researchers from Durban’s Oceanographic Research Institute, embarked on a four-day fish tagging expedition in Sodwana Bay.
‘The purpose of these trips is to compare the catch rate within the no-take sanctuary areas of the St Lucia Marine Reserve to that of the adjacent exploited areas, while at the same time gathering data on movement patterns and growth rates of the fish,’ said Rob Kyle, Senior Aquarist at uShaka Marine World.
Standard rock and surf spinning tackle is used.
Barbs are squashed and using circle hooks is encouraged to reduce chances of fish being injured from swallowing a hook.
PHOTO: SAAMBR
Before throwing out a bait or lure, a bucketful of sea water is collected and placed at the tagging station.
When a fish is landed, it placed in a water bucket as soon as possible while the tagging equipment is prepared.
‘Sometimes fish are too big for the bucket, and in these instances they are put in head first and held there until the stretcher is ready.’
This is often the case with giant trevallys (GT), which were among the species caught on the expedition.
The fish are measured on a PVC stretcher with a stainless steel ruler set down the middle, to allow for an accurate measurement.
A wet rag is placed over the fish’s head to help it remain calm and not flail about.
Once tagged, measured and hopefully photographed, the fish is released.
All this is done in 30 seconds or less.
Fraught with excitement, including the anglers being stung by a shoal of bluebottles and measuring a strong GT in the shorebreak, the expedition caught 278 fish, of which 165 were tagged and nine were recaptured.
Catch per unit effort was double in the sanctuary area compared with exploited zones.
‘This shows that the no-take areas are really working,’ said Kyle.
The majority of recaptured fish showed little movement, with the exception of one speckled snapper which had travelled from Lone Tree south of Leven Point to the middle of the sanctuary area – a distance of 19km.
‘This is a relatively big movement for the species and it’s always interesting to see that in even the most resident of species, there are those individuals who feel the need to travel.’
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