1. An evaluation of the use of the Traditional Ecological Knowledge of the fishers in the management of their fisheries: the case of the Galician purse seine fleet
ICES Annual Science Conference, A Coruña, September 2014
Pablo Pita, Duarte Fernández-Vidal and Ramón Muíño

2. The use of the TEK of the fishers in the management
TEK of fishermen can provide detailed spatial information in a way that is both quick and cost-efficient (Neis et al. 1999).
TEK-based mapping may be very accurate (e.g. Anuchiracheeva et al. 2003; Aswani and Lauer 2006).
Aswani, S., and Lauer, M Benthic mapping using local aerial photo interpretation and resident taxa inventories for designing marine protected areas. Environmental conservation 33:
Anuchiracheeva, S., Demaine, H., Shivakoti, G.P., and Ruddle, K Systematizing local knowledge using GIS: fisheries management in Bang Saphan Bay, Thailand. Ocean & Coastal Management 46:
Neis, B., Schneider, D.C., Felt, L., Haedrich, R.L., Fischer, J., and Hutchings, J.A Fisheries assessment: what can be learned from interviewing resource users? Canadian Journal of Fisheries and Aquatic Sciences 56:

3. The use of the TEK of the fishers in the management
However
TEK has been hardly integrated into fisheries management models (Huntington 2000), partly because the lack of studies analysing the reliability and accuracy of the results.
Huntington, H.P Using Traditional Ecological Knowledge in Science: Methods and Applications. Ecological Applications 10:

4. The purse seine fishery of Galicia
4% of the 5000 coastal vessels.
16% of the total fishing power.
33% of the landings.
10% of the first sale value.
Scientific spatial knowledge on the fishery is limited or non-existent.
Source: Instituto Galego de Estadística (2014)
Source: (2014)

5. The purse seine fishery of the Ría of Arousa
30 vessels
Our study area in the Ría of Arousa
Source: (2014)

6. TEK-based cartography of fishing grounds
We identified local experts by a snowball procedure and performed personal interviews with maps to fishers and skippers, including 3 purse seine vessels.
In the interviews, they sketched the extension of the areas where they fish each target species.
The information was introduced in a GIS superimposing the information obtained from each fisher to achieve a single layer.

7. TEK-based cartography of fishing grounds
41 species in 456 km2.
63% finfish.
22% molluscs.
12% crustaceans.
2% equinoderms.

8. TEK-based cartography of fishing grounds
Trachurus trachurus
Atlantic horse mackerel
Scomber scombrus
Atlantic mackerel
Diplodus sargus
White sea bream

9. 1-year fishery monitoring
Data loggers
Log-books

10. 1-year fishery monitoring
Identification of fishing grounds
Speed (km·h-1)
Speed (km·h-1)
Time
Cut V=4 km·h-1

11. 1-year fishery monitoring
Identification of fishing grounds
223 log-books
232 fishing routes

12. 1-year fishery monitoring
Scientific name
English name
CPUE ((kg·m-2)·1000)
Total
Used
Ammodytidae
Sand eel
35.22
Atherina presbyter
Sand smelt
11.72
6.97
Belone belone
Garfish
68.75
0.00
Boops boops
Bogue
Dicentrarchus labrax
European sea bass
2.81
Diplodus sargus
White sea bream
426.88
64.14
Engraulis encrasicolus
European anchovy
351.56
Isurus oxyrinchus
Short fin mako
6.25
Katsuwonus pelamis
Skipjack tuna
49.53
16.87
Liza aurata
Golden grey mullet
11.20
Merluccius merluccius
European hake
17.50
Pagellus bogaraveo
Black spot sea bream
23.44
Pagellus acarne
Axillary sea bream
34.38
4.65
Salmo trutta trutta
Sea trout
0.31
Sardina pilchardus
European pilchard
242.97
61.52
Scomber japonicus
Chub mackerel
759.52
Scomber scombrus
Atlantic mackerel
326.25
Spondyliosoma cantharus
Black sea bream
316.29
101.70
Trachurus picturatus
Blue jack mackerel
423.40
Trachurus trachurus
Atlantic horse mackerel
Trisopterus luscus
Pouting
7.03
21 species.
T. trachurus: 216 t

13. Coincidences TEK cartography and fisheries monitoring
Species
Coincidences with TEK cartography
Total
Reported catches 1 2 3 4 5
Ammodytidae
2063 41 6 39
Diplodus sargus
1149
292
261
337 69 24 9
Engraulis encrasicolus
Pagellus bogaraveo
2035 75 15
Sardina pilchardus
671
1439 20 46
Scomber scombrus
364
1303
443
124
200 49
Spondyliosoma cantharus
1956
154
214 10
Trachurus trachurus
398
164
833
182
533
251
125
685
168
373

14. Coincidences TEK cartography and fisheries monitoring
Logistic GAM (Hastie and Tibshirani 1990): positions of the fishing hauls in layers of the TEK-based fishing ground cartography.
Even in a multi-species fishery.
The fishers tended to fish each species in the same areas included in the TEK cartography, especially when catches were reported in the GPS positions. Furthermore, T. trachurus, with a very detailed cartography, with many overlaps between informants and very captured, was mostly caught in fishing grounds indicated by more than one informant.
Hastie, T., and Tibshirani, R.J Generalized Additive Models. Chapman and Hall, London.

15. Contact and information:
Acknowledgements
This study was financed by GAP2 project ( It would not have been possible without the involvement of our partners in the project: the FGCP ( and the Cofradías of Aguiño, Cambados and Ribeira.