Fishers local ecological knowledge improves understanding of - - PowerPoint PPT Presentation

Photo: Anais Prestes

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

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

➢ 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 Brazilian Amazon as study case for tropical freshwater fisheries

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

Time

Past (20 years ago) Actual

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

Tapajós River Negro River 16 fishing communities, 8 in Tapajós and 8 in Negro River, 4 inside, 4 outside (red squares) Extractive Reserves (RESEX).

RESEX Tapajos-Arapiuns 1998 RESEX do Unini 2006

Communities River Lake Communities River Lake

➢ 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)

Methods

Results Tapajos: fishers cited 43 fish species (names)

➢ 36 in the RESEX ➢ 31 outside

2006

➢ 29 in the RESEX ➢ 28 outside

2016 1996 1998

RESEX Tapajós-Arapiuns RESEX Unini

Negro: fishers cited a total of 32 fish species (names)

➢ 28 in the RESEX ➢ 13 outside ➢ 15 in the RESEX ➢ 16 outside

Past (20 years ago) Actual

10 20 30 40 50 60 70 80 % of fishers Fish

Tapajos Outside (n= 73 fishers)

20 years Actual

Tapajos: similar fish caught now and in the past outside = 79.7 % similarity

Large valuable fish less cited and decreased Increased citations of smaller fish and tucunare Size

10 20 30 40 50 60 70 % of fishers Fish

Tapajos RESEX (n= 88 fishers)

20 years Actual

Similar fish caught now and in the past inside RESEX = 83.24 % similarity

Same pattern on catches of large and smaller fish

10 20 30 40 50 60 70 80 90 % of fishers Fish

Negro Outside (n = 46 fishers)

20 years Actual

Negro: similar fish caught now and in the past outside = 83 % similarity

Few citations of large, valuable fish Increased citations of smaller fish and tucunare

Similar fish caught now and in the past inside RESEX = 64 % similarity

10 20 30 40 50 60 70 80 90 % of fishers Fish

Negro RESEX (n = 74 fishers)

20 years Actual

Few citations of large fish, only in the past Increased citations of tucunaré and piranha

• 50
• 40
• 30
• 20
• 10

10 20 30 Tucunaré Aracu Caratinga Pacu Jaraqui Pescada Filhote Charuto Dourada Sarda % of fishers Tapajos River: Outside (4 communities, n = 73 fishers) Increased Same Decreased

• 50
• 40
• 30
• 20
• 10

10 20 30 Tucunaré Pescada Caratinga Jaraqui Mapará Dourada Filhote Aracu Sarda Branquinha % of fishers Tapajos River: RESEX (4 communities, n = 88 fishers) Overall decrease on fish abundance over time!

• 40
• 30
• 20
• 10

10 20 30 40 Pacu Tucunaré Jaraqui Aracu Matrinxã Piranha Acará Surubim Aruanã Filhote % of fishers Negro River: Outside (4 communities, n = 46 fishers) Increased Same Decreased

• 20

20 40 60 80 Piranha Pacu Tucunaré Aracu Jaraqui Acará Matrinxã Traira Pacui Aruanã % of fishers Negro River: RESEX (4 communities, n = 74 fishers) Decreased outside Increased inside

A r a c u B a r a r u r á B

• c

ó B r a n q u i n h a C a r a t i n g a C h a p e r e m a C h a r u t

• D
• u

r a d a F i l h

• t

e F u r a

• c

a l ç a J a r a q u i M a p a r á P a c u P e s c a d a P i a u P i r a r u c u S a r d a S u r u b i m T a m b a q u i T u c u n a r é

Fish species

• 1.0
• 0.6
• 0.2

0.2 0.6 1.0 A b u n d a n c e t r e n d

• utside

RESEX REGION

Comparison of abundance trends, for each fish species (x proportion of fishers who mentioned the trend): Increased= +1, Same = 0, Decreased = -1

Tapajos

All fish decreased in abundance, except a small, less valuable fish inside RESEX

A c a r á A r a c u A r u a n ã F i l h

• t

e J a r a q u i M a t r i n x ã P a c u P a c u i P i r a n h a S u r u b i m T r a i r a T u c u n a r é

Fish species

• 1.0
• 0.6
• 0.2

0.2 0.6 1.0 Abundance trend

• utside

RESEX REGION

Negro

Overall opposite trends: + Increased inside the RESEX

• Decreased outside

Concluding remarks:

Ecological filter before 20 years ago + reduced abundance of exploited fish?

20 years ago Actual

Photo: Pedro Peixoto

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

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??