Friday, May 10, 2013

PRELIMINARY REPORT ON DISEASE MONITORING (EUS) DURING THE 2013 NATIONAL CROKANGO ANGLING BONANZA: 1-4 May 2013



Mauro Rosa from Crokango Angling Club
 BY
VICTORIA MUMBA and TOBIAS NGHWADA


 INTRODUCTION

Angling competition is vital in tourism sector. It attract tourist to the country who buy fishing license to participate in the competition which contributes to economic growth of the country.  Angling competitions also compliment fisheries research by providing valuable information to the MFMR database which research team cannot get through their survey. MFMR fisheries research uses gillnet which catches a very small number of the large fish that leads to under representation of large fish. During angling competition the anglers catch big size fish that reduce the under representation of large fish during surveys. Angling competitions provide opportunity to monitor fish diseases such as Epizootic Ulcerative Syndrome (EUS) on big fishes.  

There are several animal health problems that can affect both inland freshwater fisheries and aquaculture. Epizootic Ulcerative Syndrome (EUS) is one of the fish diseases that was first reported in Namibia in Caprivi region in November 2006. In September 2008, EUS spread further to the Kavango region and was confirmed on fish farms of Kavango region (Mpungu fish farm, Karovo fish farm and Shipapo wa Mbamba Ngandu fish farm).  The existence of EUS in Namibia may hamper inland aquaculture development which is seen as a top priority program for the Ministry of Fisheries and Marine Resource (MFMR). The disease may also cause poverty, as the people of Namibia that are living in the North eastern regions rely heavenly on fish as a cheap source of protein. For that reason EUS monitoring program has been set up angling competition and biological surveys in the North eastern Regions.
  
MFMR has so far undertaken the initiatives in collaboration with NNF/WWF project during 2006 to 2009 to monitor EUS by carrying out surveys on each farm and affected rivers of Caprivi and Kavango regions. These initiatives need to be broadened and extend to other regions in order to monitor EUS in the entire Namibia.
   
BACKGROUND OF EUS
EUS is a serious fish disease which has swept across most Asian countries. It was first reported in 1970’s in Asia and United States of America. The outbreak of Epizootic Ulcerative Syndrome (EUS) was reported for the first time in Namibia in October 2006 in Caprivi region-Zambezi/Chobe river system. In September 2008, EUS spread further to Kavango Region and was confirmed on fish farms of the Region. During the outbreak the monitoring was conducted through surveys in collaboration with NNF/WWF project on each farm and affected rivers of Caprivi and Kavango Regions. Since then,
  Ministry of Fisheries and Marine Resource (MFMR) has been monitoring EUS through surveys, river excursions, public alarms, and angling competitions.

Information found for the year 2010 revealed that there were more cases of fish with clinical signs of EUS in Kavango River than those of Caprivi Region. During the outbreak, there were high cases of fish with clinical signs of EUS in Caprivi Region, but now they are on decline. The information  also revealed  that fish samples with suspected cases of EUS that had clear wounds are turning out to be negative, while the samples that had ulcers with fungal growth on the surface turning out to be positive. 

Based on laboratory results obtained  there is no reason for a concern that the EUS fish disease is a potential threat to the Kavango River Ecosystem, however continuous monitoring for the disease is highly needed as diseases have a tendency to manifest that makes it difficult to predict its future impacts on the ecosystem. In addition, it is preliminarily concluded that fungal growth is limited on clinical signs of EUS at advanced stage upon culturing.                   

This report will consist of information gathered during angling competition that took place on the  Kavango River, at Mupapama (Crockango Camp)  on the 01 – 04th May 2013.

METHODS
There were about 78 boats for the Crockango 2013 angling competition. Each boat was carrying 2 to 3 anglers using only hooks and lines. Anglers started fishing at 5:00 am in the morning and ended fishing 16h00 – 19h30. 

Fig. 1. Holding tank
Fish caught were kept on the boats holding tank to keep the fish alive and brought on shore for length, weight measurements and species record. Fish that were alive and active was release back to the river after measurements, while the fish that were weak was put in the holding tank to gain energy back and release back in the river.  Fish that fail to gain strength (for instance remains swimming on the surface) was too weak to survive. Therefore the weak fish was not release in the river due to less chance of survival.

Fig. 2. Sampling station
Fig. 3. Sample collected 
Fish with lesions were also collected for monitoring of EUS. Samples were taken and preserved in 10% formalin.
Fig 4. Sampling bottles
RESULTS 
Fish caught

Fish caught during angling competition were grouped as follows: Breams, Squekers, Barbel fish,  and Tigerfish. 
Fig. 5. Fish with lesions
 Suspected EUS fish caught during angling competition

 Fish caught were Nembwe, Pink Happy and babel during angling competition (Table 2).  All suspected EUS fish had an average total length of about 400mm.


Table 2: Suspected EUS fish during angling competition at Kavango River

Species collected
Suspected EUS Fish in numbers
Sargochromis giardi
2
Serranochromis robustus
6
Clarias gariepinus
1
Hydrocynus vittatus
0
   
Discussion

Fish handling is a critical stage during angling competition. Fish need to be handled carefully in order to survive. The anglers were holding the fish for too long before releasing the fish back to the river. Anglers get excited especially when they see their colleagues caught big fish. The big fish of that species will be circulated for the picture taking and at the end the fish will be exhausted. 

Most anglers departed for fishing at 6am  and returned as from 16h00 – 19h30pm. Fish caught were kept on the boats’ holding tank for too long.  This also exhausts fish to a certain extent and makes it difficult to identify problems that require immediate attention.
For length and weight measurements, a compliment is given to the guy who was weighing fish. Apparently, it was agreed upon that all dead fish should be given to the community.
  
CONCLUSION

Since Kamutjonga Inland Fisheries Institute does not have the chemicals and equipments for disease analysis, the Samples collected from Crockango fishing competition will be taken to Zambia for laboratory analysis for confirmation of EUS. 

RECOMMENDATION
  •   The picture taking should be minimized to reduce the exhausting of fish.
  •  Anglers should start fishing at 6:00am and have a break at 12h00-14h00. This will  allow the anglers to bring the fish caught in the morning hours to be weighed and released back to the river and continue  fishing again at 14h00 -18h00pm. Or alternatively look into a chart system for all species or more weigh stations to reduce stress on fish 
  •  Children at the competition were assisting with fish releasing. This should be avoided as children do not know how to handle fish which let some fish to fall down especially the heavy one.  There were guys to assist with fish releasing, but these guys can let fish die deliberately so they could have them. This has result to negligence, regulation need to be revised.
  •  KIFI will look into equiping itself for on station analysis of disease samples 








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