Revista de Gestão Costeira Integrada
Volume 12, Número 4, Dezembro 2012, Páginas 477-482

DOI: 10.5894/rgci338
* Submission: June 05, 2012; Evaluation: July 09, 2012; Reception of revised manuscript: July 26, 2012; Accepted: October 5, 2012; Available on-line: October 10, 2012

Influence of rainfall on tropical coastal artisanal fisheries – a case study of Northern Mozambique *

Influência da precipitação nas pescarias artesanais tropicais – o estudo de caso da região norte de Moçambique

Antonio Mubango Hoguane ^{@, 1}, Ezidio da Lucia Cuamba ² , Tor Gammelsrød ³

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@ - Corresponding author
1 - School of Marine and Coastal Sciences, Eduardo Mondlane University, PO Box 128, Quelimane, Mozambique. e-mail: [email protected]
2 - Pemba Marine Research Centre (CEPAM), P.O.Box 306, Pemba, Mozambique. e-mail: [email protected]
3 - Institute of Geophysics, University of Bergen, Allegt 70, 5007 Bergen, Norway. e-mail: [email protected]

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RESUMO
The artisanal catch contributed about 87% of the overall annual marine fish production in Mozambique, estimated to 115,000 -140,000 tons, as per fish statistics of the period 2000 and 2004. The availability of most of the coastal marine fisheries depends on a number of factors among which the freshwater input into the coastal waters, either though the rivers or coastal rainfall drainage, as it provides nutrients into the coastal waters that stimulate the primary production. This would enhance the survival and growth of coastal fish species, most of which nurse and breed in estuaries and mangrove swamps. The effect of the freshwater input into the coastal zones through the rainfall 1995-2008 on the landing of artisanal catches 1998-2008 in the northern Mozambique (15o– 17o S) was analysed. The results showed that the artisanal annual total catch were significantly correlated to the coastal rainfall lagged two years, with r= 0.7862 and p=0.004. The two-year lag matches the longevity of Engraulididae, Clupeidae and Leiognathidae, and the maturity age of Carangidea, the top four dominant fish families. This result emphasises the role of freshwater in productivity of coastal waters and in the survival and growth rate of the fish population during the earlier stage of their life cycle. The findings in this work may contribute to predict the fish production, and hence improve the management measures of the artisanal fisheries, through setting sustainable fishing quotas. Further, our results contribute to improve our understanding of the climate influence on artisanal fisheries, and so to provide insights of their vulnerability and adaptive capacity to the climate change.

Palavras-chave: Coastal rainfall, coastal productivity, fish growth, catch prediction, fisheries management.

ABSTRACT
As capturas da pesca artesanal em Moçambique contribuem em cerca de 87% da captura total anual do país. De acordo com as estatísticas no período de 2000 a 2004, as capturas estimadas deste subsector das pescas foram cerca de 115.000 a 140.000 toneladas por ano. A abundância das pescarias marinhas costeiras depende de muitos fatores, dentre os quais a água doce dos rios disponibilizada quer através dos rios ou de águas pluviais drenadas de bacias hidrográficas costeiras, uma vez que providencia nutrientes que fertilizam as águas costeiras, estimulando desse modo a produtividade das mesmas. Isto por sua vez aumenta a sobrevivência e crescimento dos peixes, que na sua maioria crescem e se desenvolvem nos estuários e manguezais. Neste trabalho analisa-se o efeito de água doce, parametrizada por precipitação anual costeira no período de 1995 a 2008, nas capturas artesanais nos anos de 1998 a 2008, na zona norte de Moçambique (15o – 17o S). Os resultados indicam haver uma correlação positiva significativa entre as capturas artesanais anuais e a precipitação costeira anual registada dois anos antes (r=0,7862 e p=0.004). O desfasamento de dois anos entre a precipitação e as capturas está relacionado com o tempo de vida nas famílias Engraulididae, Clupeidae e Leiognathidae e com a idade de maturação na família Carangidea, constituindo estas as principais famílias que compõe as capturas. Estes resultados realçam o papel da água doce drenada para as zonas costeiras na produtividade destas e na sobrevivência e crescimento das populações de peixes durante a fase inicial do seu ciclo de vida. Os resultados deste trabalho podem contribuir para prever as capturas e melhorar a gestão das pescarias artesanais através, por exemplo, de estabelecimento de quotas de pesca em função das previsões. Mais ainda, as discussões realizadas contribuem para melhor a nossa compreensão da influência de fatores climáticos nas pescarias artesanais e avançar sugestões sobre a sua vulnerabilidade e capacidade de adaptação às mudanças climáticas.

Keywords: precipitação costeira, produtividade costeira, crescimento de peixe, previsão de capturas, gestão de pescarias.

 

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