NCC Environmental Manager, Chris Wilkinson shares his love for fishing and explores tagging and its scientific benefits.
A bit of background
As most of the NCC office and field staff already know, I enjoy fishing and if I could fish every day I would. When I post my catches on the NCC internal staff forum under the NCC internal fishing league, I get bombarded with questions with regards to what I did with the fish once they were caught or why am I always fishing? Often people get the wrong impression when they see photos of these amazing animals on the beach. I know it’s not everyone’s idea of conservation, but rest assured it’s all for a good scientific cause.
When working at the Oceanographic Research Institute (ORI) in Durban I was introduced to the ORI long term tagging project. I ended up working very closely with this project and often went on tagging trips to the Pondoland Marine Protected Area (MPA) in the Transkei and the St Lucia MPA at Cape Vidal. I also spent many slow periods between field trips entering all the tag returns from fish caught over the whole country. I remember being very jealous at the amount of big fish being caught in the Cape and kept a close eye on the Bronze Whaler / Copper Sharks being tagged in summer, plotting how I would get one of these beautiful creatures on my tagged list. I could not have asked for a better welcome back to Cape Town than landing two stunning fish (one of 120kg and one of 80kg) on my first weekend back fishing on the beaches at Macassar. That day we landed the fish correctly, measured, tagged them and they both swam away strongly. Now I can’t wait to see where these sharks will turn up again and see how much and how quickly they have grown. My bet is they will follow the sardines up to Durban for the annual sardine run one of these years.
On to the scientific stuff
In order to successfully manage and conserve the fish stocks, there needs to be good co-operation between users, managers and scientists. Scientists need good reliable data in order to undertake sound stock assessments and to develop new regulations to ensure sustainability in the future. The ORI tagging project achieves both these goals by allowing users (fishermen) to actively participate in the accumulation of good data for the use in stock assessments. The project encourages conservation conscious anglers to tag and release their catch, thereby generating information on fish movements and patterns, growth and fish mortality.
The ORI fish tagging programme was started in 1984 - almost 30 years ago. Currently there are over 5000 tagging anglers throughout South Africa, Namibia and Mozambique who have tagged over 250 000 fish. The recapture rate for these tagged fish is 5.2% i.e. 13 192 fish have been recaptured.
When an angler catches a fish, he needs to record the species, date, location and length on the tag card. The fish is then tagged with a numbered tag that corresponds to the number on the tag card and released. Great importance is placed on how to handle the fish correctly as good scientific information relies on its survival.
Good fishing handling tips for your next trip to the beach:
- No gaffing of sharks and rays
- Be prepared with your tagging equipment, have it close at hand to minimise the time the fish is out of the water
- Handle the fish carefully and cover the fish’s eyes with a wet cloth to minimise stress
- Land fish inside a stretcher filled with water
- Fish with barbless hooks (preferably circle) for minimal damage to the fish
- Only tag fish over 30cm
What to do if you have caught a tagged fish:
If you are lucky to catch a tagged fish, it is very important to send the following information to the tagging officer at ORI firstname.lastname@example.org:
- Place where it was caught
- If you released it or kept it
Contrary to belief there is no reward for catching a tagged fish and you do not get into trouble if you decided to keep the fish. A joke amongst anglers is that catching a tagged fish is just like catching your supper with a free toothpick included.
Interesting recaptures from the ORI 2011 newsletter:
CAPE YELLOWTAIL (Seriolalalandi)
16 RECAPTURED = 3.07% RECAPTURE RATE
LONGEST DISTANCE TRAVELLED 1 746 KM
MAXIMUM DAYS FREE 1 287 (3.5 YEARS)
2011 was certainly a year of amazing recaptures! On the 20/08/2011 a small (775 mmFL) Cape Yellowtail was tagged and released by Warwick Leslie off Dassen Island on the West Coast. Just 30 days later on the 19/11/2011, this fish was recaptured by Greg Defilippi offshore of Stiebel Rocks just south of Hibberdene on the KZN south coast (yes you read right!). In this short period this fish had swum an amazing 1 746 km, which amounts to a whopping 58 km per day. This was really quite remarkable for a small fish that only weighed in at 6.7kg.
RED STEENBRAS (Petrusrupestris)
1 071 TAGGED
77 RECAPTURED = 7.2% RECAPTURE RATE
LONGEST DISTANCE TRAVELLED 923 KM
MAXIMUM DAYS FREE 8 080 (22.14 YEARS)
After we thought it couldn't get any better with regards to the quality of the recaptures received in 2011, there was one more still to come, and what a record it turned out to be! On the 28/12/2011 Andrew Gericke was fishing approximately 6 miles off Kei Mouth when he hooked a red steenbras or 'copper' as they are commonly known in the Eastern Cape. After successfully landing the fish he noticed there was a tag with a lot of algae growth sticking out the fish. After taking down the relevant recapture information, he reported the tag recapture to the Border Deep Sea Angling Association who contacted ORI with the information. To our surprise, this individual fish had been tagged by Bruce Mann (ORI Senior Scientist) from the shore in the Tsitsikamma National Park in 1989. This meant it had been at liberty for 22.1 years! In all that time free it had not only escaped capture from commercial and recreational fishermen, but had also moved 532 km north and grown 17.9 kgs (370 mm). This recapture is not only the longest time at liberty for a red steenbras in South Africa, but is also a new record for any teleost (bony fish) tagged in South Africa and possibly the world! Yet again this recapture proves the exceptional longevity of red steenbras and the durability of the tags we are using supplied by Hallprint©Australia.
SPOTTED GULLYSHARK (Triakismegalopterus)
7 771 TAGGED
419 RECAPTURED = 5.4% RECAPTURE RATE
LONGEST DISTANCE TRAVELLED 911 KM
MAXIMUM DAYS FREE 6 632 (18.2 YEARS)
During 2011 the record for the longest time at liberty by a spotted Gullyshark was broken. On 30/10/1993 Mr JJ Crous tagged and released a spotted gullyshark of 1 020 mm total length from the shore at Cape Agulhas Light House. On the 02/03/2011 this individual was recaptured at Stuisbaai having been at liberty for 6 332 days (i.e. 18.2 years). This smashes the old record by 844 days! This fish had grown 580 mm in its 18 years at liberty and had only moved 7 km.
This recapture again proves the importance of long-term tagging projects. It is only after many years that vital information on the growth rate and movement patterns of these long-lived species can be obtained.
Tight lines guys!