Who will kill them first, Man or Climate? · Who will kill them first, Climate or Man? Sreenath, K....

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Who will kill them first, Climate or Man? Sreenath, K. R., Gyanaranjan Dash, Mohammed Koya, K. , Swatipriyanka Sen, Vinayakumar, V., Divu, D., Pradhan, R., Sukhadhane, K., Sonia Kumari, Makwana Nayan, P., Joshi, K. K. and Zacharia, P. U. Regional Centre of ICAR - Central Marine Fisheries Research Institute, Veraval, Gujarat-362269 1. Background It is evident that the variability of fish abundance in the sea has been increasing over time. This variability might be due to climate factors or anthropogenic factors such as fishing. Challenge of the modern fishery management is to distinguish between the two and take account of these sources of variability. As all of the marine fisheries resources of India are currently under exploitation, there is no control group available to distinguish climate effects from fishing effects. Here ,we are utilizing methods involving statistical controls for this purpose. 4. Results continued.. Fig.1. Significant Beta weights (β) of model fitted for each fish species’ abundance with SST and fishing effort. Complete dominance weights showed that fishing effort contributes more variance than SST (Fig. 2) . Fig.2. Complete dominance weights (CD 0 ) of model fitted for each fish species’ abundance with SST and fishing effort . 2. Aim The goal of this work is to distinguish impact due to fishing on fish abundance from those due to climate , with the hope that former can be controlled where as the latter can be observed and (possibly) predicted. 3. Data and Method Data Abundance 30 years Catch (Kg) and Effort (fishing days) has been taken from the ICAR-CMFRI database and Catch per unit effort (CPUE) is utilized as a proxy to fish abundance for thirty six (36) commercially important species. Climate variable The Sea Surface Temperature (SST) data for 2x 2 o grid (69-71 o N, 19- 21 o E) have been gathered from International Comprehensive Ocean-Atmosphere Data Set (ICOADS) for a period of 30 years (1985 to 2014). Method Data analysis has been performed using the R 3.3.2 software. Stepwise linear regression was performed to fit model for the abundance of all the 36 species with SST and fishing effort. Yhat’ package was used for analyzing variable importance using the beta weights (β) and complete dominance (CD0). 5. Conclusion Results of the study confirms that the impact of fishing pressure is very high and more wide spread as compared to that of sea surface temperature on the fish abundance. However, as14% of species have shown SST also as one of the reasons for their population variability, measures to control fishing needs to be increased simultaneous with conservative management measures which can increase resilience of vulnerable species to climate variability. Acknowledgements We express our gratitude to the Director, ICAR-CMFRI for the guidance and facilities put forward for conducting this work. We also thank ICAR and National Innovation on Climate Resilient Agriculture (NICRA) for support and providing fund for this work. -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 Acetes indicus Harpadon nehereus Coilia dussumieri Sardinella longiceps Rastrelliger kanagurta Euthynnus affinis Thunnus tonggol Scomberomorus gutatus Scoliodon laticaudus Otolithes biauritus Protonibea diacanthus Metapanaeus monoceros Metapenaeus affinis Parapenaeopsis stylifera Penaeus semisulcatus Fenneropenaeus merguiensis Solenocera crassicornis Charybdis feriata Portunus sanguinolentus Panulirus polyphagus Trichurus lepturus Pampus argenteus Parastromateus niger P tenuispinis Himantura imbricata Otolithoides cuvieri Beta weights (β) Fish Species Beta weights (β) plot SST Effort 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 A.indicus H.nehereus C.dussumieri S.longiceps R.kanagurta E.affinis T.tonggol S.gutatus S.laticaudus O.biauritus P.diacanthus M.monoceros M.affinis P.stylifera P.semisulcatus P.merguiensis S.crassicornis C.feriata P.sanguinolentus P.polyphagus T.lepturus P.argenteus P.niger P.tenuispinis H.imbricata O.cuvieri Complete dominance (CD 0 ) Fish Species Complete dominance plot SST Effort 4. Results Regression has yielded linear models of all species with significant coefficient of determination. Out of 36 species studied, twenty six (26) species (mostly demersals) showed significant negative β for effort and five (5) species have showed negative β for SST (Fig. 1). Another six (6 ) species have showed positive β with SST. However, for all the 26 species, the negative influence of fishing effort was much higher as compared to that of SST. Presented by Dr. Sreenath, K. R. at 1 st International Agrobiodiversity Congress, 6-9 November , New Delhi Poster No. 1794

Transcript of Who will kill them first, Man or Climate? · Who will kill them first, Climate or Man? Sreenath, K....

Page 1: Who will kill them first, Man or Climate? · Who will kill them first, Climate or Man? Sreenath, K. R., Gyanaranjan Dash, Mohammed Koya, K. , Swatipriyanka Sen, Vinayakumar, V., Divu,

Who will kill them first, Climate or Man?

Sreenath, K. R., Gyanaranjan Dash, Mohammed Koya, K. , Swatipriyanka Sen, Vinayakumar, V., Divu,

D., Pradhan, R., Sukhadhane, K., Sonia Kumari, Makwana Nayan, P., Joshi, K. K. and Zacharia, P. U.

Regional Centre of ICAR - Central Marine Fisheries Research Institute, Veraval, Gujarat-362269

1. Background

It is evident that the variability of fish abundance in the sea

has been increasing over time. This variability might be due to

climate factors or anthropogenic factors such as fishing.

Challenge of the modern fishery management is to distinguish

between the two and take account of these sources of variability.

As all of the marine fisheries resources of India are currently

under exploitation, there is no control group available to

distinguish climate effects from fishing effects. Here ,we are

utilizing methods involving statistical controls for this purpose.

4. Results continued..

Fig.1. Significant Beta weights (β) of model fitted for each fish species’ abundance with SST and fishing effort.

Complete dominance weights showed that fishing effort

contributes more variance than SST (Fig. 2) .

Fig.2. Complete dominance weights (CD0) of model fitted for each fish

species’ abundance with SST and fishing effort.

2. Aim

The goal of this work is to distinguish impact due to

fishing on fish abundance from those due to climate , with

the hope that former can be controlled where as the latter can be

observed and (possibly) predicted.

3. Data and Method

Data

Abundance – 30 years Catch (Kg) and Effort (fishing days) has

been taken from the ICAR-CMFRI database and Catch per unit

effort (CPUE) is utilized as a proxy to fish abundance for thirty

six (36) commercially important species.

Climate variable – The Sea Surface Temperature (SST) data for

2x 2 o grid (69-71o N, 19- 21o E) have been gathered from

International Comprehensive Ocean-Atmosphere Data Set

(ICOADS) for a period of 30 years (1985 to 2014).

Method

Data analysis has been performed using the R 3.3.2 software.

Stepwise linear regression was performed to fit model for the

abundance of all the 36 species with SST and fishing effort.

‘Yhat’ package was used for analyzing variable importance

using the beta weights (β) and complete dominance (CD0).

5. Conclusion

Results of the study confirms that the impact of fishing

pressure is very high and more wide spread as compared

to that of sea surface temperature on the fish abundance.

However, as14% of species have shown SST also as one of the

reasons for their population variability, measures to control

fishing needs to be increased simultaneous with conservative

management measures which can increase resilience of

vulnerable species to climate variability.

Acknowledgements

We express our gratitude to the Director, ICAR-CMFRI for the

guidance and facilities put forward for conducting this work. We

also thank ICAR and National Innovation on Climate Resilient

Agriculture (NICRA) for support and providing fund for this work.

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4. Results

Regression has yielded linear models of all species with

significant coefficient of determination. Out of 36 species studied,

twenty six (26) species (mostly demersals) showed significant

negative β for effort and five (5) species have showed negative β

for SST (Fig. 1). Another six (6 ) species have showed positive β

with SST. However, for all the 26 species, the negative influence

of fishing effort was much higher as compared to that of SST.

Presented by Dr. Sreenath, K. R. at 1 st International Agrobiodiversity Congress, 6-9 November , New Delhi Poster No. 1794