Fishers local ecological knowledge improves understanding of - PowerPoint PPT Presentation

Fisher’s local ecological knowledge improves understanding of temporal changes on fishing resources in tropical rivers Renato A. M. Silvano Dep. Ecology Universidade Federal do Rio Grande do Sul Gustavo Hallwass Universidade Federal do Oeste do Para Photo: Anais Prestes

Research Project: Linking sustainability of small-scale fisheries, fishers’ knowledge, conservation and co -management of biodiversity in large rivers of the Brazilian Amazon PEER Cycle 4 Grant Award Number: AID-OAA-A-11

Coordinated by Brenda Parlee, University of Alberta

Brazilian Amazon Tapajos Negro

Brazilian Amazon as study case for tropical freshwater fisheries ➢ Small-scale fisheries important for local economy and food security ➢ People affect (overfishing) and are affected (food supply) by fish ➢ Lack of scientific information on fisheries and fish ➢ Fishers have good and detailed knowledge about fish: fill data gaps

Temporal change on freshwater fish assemblages: Fishing down = decline on fish size (Welcomme 1999) Time ➢ Fishing pressure ➢ New fishing gear ➢ Market demand for fish

Main goals: ➢ Analyze fishers’ local ecological knowledge (LEK) on temporal trends of composition and abundance of fish catches. ➢ Comparing these perceived trends inside X outside protected areas in two rivers in the Brazilian Amazon. Hypotheses: ➢ Changed composition with a decline on fish abundanceover time ➢ Protectedareas show none or less changes or declines Past (20 years ago) Actual

Communities Communities River River Lake Lake RESEX RESEX do Unini Tapajos-Arapiuns 2006 1998 Tapajós River Negro River 16 fishing communities, 8 in Tapajós and 8 in Negro River, 4 inside, 4 outside (red squares) Extractive Reserves (RESEX).

Methods ➢ Individual interviews with fishers: standard questionnairewith 31 questions ➢ 5 main fish species (or groups of species) caught now (2016) and 20 years ago ➢ Changes on abundanceof most caught fish now: increased, same , decreased ➢ Snow-ballsampling: Tapajos River: 161 fishers (154 male, 7 female), average age = 48.2 years ( ± 12.7) Negro River: 120 fishers (110 male, 10 female), average age = 39.5 years ( ± 13.5)

Results Tapajos: fishers cited 43 fish species (names) ➢ 36 in the RESEX ➢ 29 in the RESEX ➢ 31 outside ➢ 28 outside Actual Past (20 years ago) 2006 1998 1996 2016 RESEX Tapajós-Arapiuns RESEX Unini Negro: fishers cited a total of 32 fish species (names) ➢ 28 in the RESEX ➢ 15 in the RESEX ➢ 13 outside ➢ 16 outside

Tapajos: similar fish caught now and in the past outside = 79.7 % similarity Tapajos Outside (n= 73 fishers) 80 Large valuable fish less cited and decreased 20 years Actual 70 Increased citations of smaller fish and 60 % of fishers tucunare 50 40 30 20 10 0 Fish Size

Similar fish caught now and in the past inside RESEX = 83.24 % similarity Tapajos RESEX (n= 88 fishers) Same pattern on catches of large and smaller fish 70 20 years Actual 60 % of fishers 50 40 30 20 10 0 Fish

Negro: similar fish caught now and in the past outside = 83 % similarity Negro Outside (n = 46 fishers) 20 years Actual 90 80 Few citations of large, 70 valuable fish 60 % of fishers Increased citations of smaller fish and tucunare 50 40 30 20 10 0 Fish

Similar fish caught now and in the past inside RESEX = 64 % similarity 20 years Actual Negro RESEX (n = 74 fishers) 90 80 % of fishers 70 60 Few citations of large fish, only in the past Increased citations of tucunaré and piranha 50 40 30 20 10 0 Fish

Tapajos River: Outside (4 communities, n = 73 fishers) 30 Increased Same Decreased 20 10 % of fishers 0 Tucunaré Aracu Caratinga Pacu Jaraqui Pescada Filhote Charuto Dourada Sarda -10 -20 -30 -40 -50 Tapajos River: RESEX (4 communities, n = 88 fishers) 30 20 10 % of fishers 0 Tucunaré Pescada Caratinga Jaraqui Mapará Dourada Filhote Aracu Sarda Branquinha -10 -20 -30 -40 Overall decrease on fish abundance over time! -50

Negro River: Outside (4 communities, n = 46 fishers) 40 Increased Same Decreased 30 % of fishers 20 10 0 Pacu Tucunaré Jaraqui Aracu Matrinxã Piranha Acará Surubim Aruanã Filhote -10 -20 -30 -40 Decreased outside 80 Increased inside 60 Negro River: RESEX (4 communities, n = 74 fishers) % of fishers 40 20 0 Piranha Pacu Tucunaré Aracu Jaraqui Acará Traira Pacui Aruanã Matrinxã -20

Comparison of abundance trends, for each fish species (x proportion of fishers who mentioned the trend): Tapajos Increased= +1, Same = 0, Decreased = -1 REGION 1.0 RESEX outside 0.6 d n All fish decreased in abundance, except a e r small, less valuable fish inside RESEX t 0.2 e c n a d -0.2 n u b A -0.6 -1.0 u á ó a a a o a e a i á u a u u a m i é u u c r c h g m t d t ç r c d a c d r q q u u o a i a a o a b n n a l a i u r a a P a r e r h p a n r B P u i i a r c r a u t c r b A r u l a a S u a i s r e h a r q F - m o M r u c a r a e p C J i n a D P S u B r P a a a u C T T h r F B C Fish species

Overall opposite trends: Negro + Increased inside the RESEX - Decreased outside REGION 1.0 RESEX outside 0.6 Abundance trend 0.2 -0.2 -0.6 -1.0 u á u ã e i ã i a m a é u u r c n t c h r x r o q c i a i a a a n a n b a a h a c n r u i P a u r r P A A l r T u r i a t r r F A a i u c J P M S u T Fish species

Concluding remarks: Ecological filter before 20 years ago + reduced abundance of exploited fish? 20 years ago Actual

Invaluable information provided by fishers ’ LEK: ➢ Tucunare: important remaining commercial fish, management needs and potential ➢ Piranhas increasingly exploited in Negro River: adaptive strategy to cope with declining fish stocks? ➢ RESEX in the Negro River has been more effective: better enforcement, no commercial fishing ➢ Fishing pressure by outside commercial fishers reduced fish abundance in Tapajos: fishing agreement Photo: Pedro Peixoto

Acknowledgments ➢ To fishers for their cooperation ➢ To USAID for funding the research ➢ The research team ➢ To Tracking Change Project and SSHRCC ➢ To you by your attention Questions??