Fishtory throws line in sea of ‘citizen science’ data

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FISH FUNDIS: Local angler Wade Labuschagne, Prof Warren Potts, angler Gerrie Botha, loca Tim Cockbain, Tanith Grant and Rhett Bennett from Rhodes University

FISH FUNDIS: Local angler Wade Labuschagne, Prof Warren Potts, angler Gerrie Botha, local Tim Cockbain, Tanith Grant and Rhett Bennett from Rhodes University

A NEW project to gather data on historical fish stocks is depending on local anglers, ocean enthusiasts and other potential citizen scientists to contribute photographs and information.

The Fishtory research team of Prof Warren Potts and Tanith Grant from Rhodes University invited all with photographs and stories to share to a meeting at the Port Alfred River and Ski-boat Club last Thursday. The turnout was small, but the researchers appreciated all contributions.

Researchers cannot collect and kill fish for information and it is necessary to gather information through “citizen science”, particularly as Fishtory is not government funded.

Local angler Wade Labuschagne contributed an angling magazine dated 1963 and photos of fish his grandfather, Eldred Bradfield, caught as a young boy, which Grant scanned onto the database.

There are about 850 000 anglers in South Africa. If they each catch five fish a year at an average size of 1kg it adds up to 4 250 tons a year. It is more than 29 inshore hake trawlers which catch 2 390 tons of hake in a year.

“Recreational fishermen have a greater impact on fish stocks than people realise,” said Potts.

When commercial fishermen see that the stocks are going down, they stop fishing until the stocks recover.  But recreational anglers may notice that fish stocks have decreased or fish sizes have decreased, and yet continue to fish.  As a result, fish stocks may continue to decrease.

In the mid-1990s, popular recreational fish like the dusky kob declined by 25% and shad between 25 and 40% in a year.  Since then these fish stocks may have declined still further.  Bronze beam and spoenskop have never been assessed.

In some places the fishermen may get together and agree to stop fishing in a certain area for a certain length of time, until the fish stocks have recovered there. For example, East London Ski-boat fishermen recently closed a reef habitat to fishing, said Potts.

Angler Gerrie Botha said the shad season was very bad this year and last year, although it was excellent in 2014, even in the Kowie. Labuschagne agreed.

“As the largest fish are normally the first to be captured by anglers, reductions in the average and maximum size of fish indicates a declining population, while increases show a rise in the population size. Information like this can be used to better manage and utilise our fish stocks, said Potts.

Fish stocks may also be affected by climate change. The temperature of the water in the Eastern Cape has increased since mid-1990s and galjoen seem to have shifted from KwaZulu-Natal towards Port Elizabeth due to their preference for colder water.

It is important to research fish stocks because of the contribution recreational fishing makes to the local economy in terms of jobs, fishing charters and licences in small towns like Port Alfred.

CatchReport is more current, and allows fishermen to log, track and share their catches. This information goes onto a national database to give a clear picture of South Africa’s marine ecosystem. Bruce Mann of the ORI tag-and-release project is a contributor.

SeaFishAtlas relates to the geographic location of fishes and is part of a larger study of biodiversity called iSpot.  The diving community, in particular, can upload photos where iSpot community experts can help you identify your catch.

“But you don’t have to be a fisherman to contribute to our knowledge of recreational fisheries,” said Potts.

Anyone with old photographs and articles can submit their data to fishtory.co.za.

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