RENDS OF MOBULIDS RAY FISHERY: A CASE SUDY OF INDONESIAN MEGAFAUNA HUNERS COMMUNIY Iqbal Herwata (iqbalherwata@gmail.com) Marine Megafauna Research Group Misool Foundation Savu Sea Program
Key point Where is Lamakera? Mobulids ray fishery Multi-approaches of conservation program Current status
Borneo Java Flores Larantuka Complex currents and high-energy upwellings creating an important marine megafauna corridor; Lamakera Home for high biodiversity of marine megafauna including (at least 32 species), many intelligent, gentle and charismatic species.
Lamakera one of the world s largest small-scale manta fishery
Big Challenge Estimated that catch rate has declined by 75% in 10 years posing a significant threat to mantas population
OUR BASELINE DAA (Lewis et al 2015) In 2002, mobulids ray estimated 1,500 individual landed (Dewar, 2002) and decline significantly in 2014 based on direct observation (Lewis et al 2015); Evidence of increased targeted mobulids fishing effort from late 1990s to present; Home for thousands mobulids which has targeted over the last decade; High targeted fishes and bycatch product.
Intervention on Mobulids fishery Multi-approaches of conservation program Since 2014 Research Build comprehensive scientific recommendation Since 2016 Law enforcement push-down Lamakerans to change Lamakeran transition Since 2016 Community outreach Build local pride Since 2015 Community empowerment Build alternative sustainable fishery
Mobulids fishery record Data collection Detail mobulids fishery landing since 2015-present in Lamakera Collected by source inside community Data collected including: time, location, taxa, DNA (2015-present) size, sex, ID (2015) Evaluation and retraining quarterly
Mobulids fishery record Summary data A) Mobulids catch composition from 2015-2017 B) Mobulids catch composition based on fishing gear 2015-2017 2% n= 12% n= 111 37% n= 340 All species Mobula tarapacana Mobula spp. 49% n= 447 Mobula japanica Mobula birostris Mobula birostris Mobula japanica 0% 20% 40% 60% 80% 100% Mobula spp. Mobula tarapacana Unknown Bycatch argeted 912 individual of mobulids was landed in Lamakera along 2015-2017; Mobula japanica is the common species which landed in Lamakera (49%, n=447); hen, Mobula japanica also the highest daily landing numbers (±SE; 3.54±0.25 individual); Manta birostris is the most targeted mobulids species by harpoon (77%, n-=263); Mobula japanica is the highest bycatch product from gillnet fishery (79% n=354).
Mobulids fishery record Seasonality A) Individual estimate of monthly mobulids landing in Lamakera 80 Mobula birostris Mobula japanica Mobula tarapacana B) Oceanographic features 70 60 50 40 30 20 10 0 J F M A M J J A S O N D Aggregation has been investigated associated with oceanographic dynamic (i.e. upwelling) in this region (Putra and Mustika in prep) he highest aggregation: May (Mobula japanica; (±SE) 51.00±33.94 individual; p-value <.0001) June (Mobula tarapacana; 6.00±4.50 individual; p-value <.0001) August (Manta birostris; 30.67±25.67 individual; p-value.0004)
Mobulids fishery record Aggregation site A) Catch location B) 3D Mobulids aggregation and plankton composition (Putra et al 2016) Manta birostris Mobula japanica Mobula tarapacana All species Low Kernel Density Estimation High Mobulids catch focused in three cluster in this region Strongly associated with zooplankton biomass hotspot, depth contour 200 meters, and gentle slope (Putra and Mustika in prep) Mostly mobulids feed on shrimp and krill (Putra et al 2016)
Mobulids fishery record How the trend of mobulids fishery since intervention? A) Catch trend before intervention B) Catch trend after intervention 1600 1400 1200 Mobula tarapacana Mobula japanica Manta birostris 1000 800 600 400 200 0 2015 2016 2017 Mobulids landing from Dewar (2002) average estimate of 1,500 individual annually and decline significantly to 213 individual in 2014 based on direct observation (Lewis et al 2015) ; Mobulids landing generally increase from 213 individual in 2014 to 327 individual in 2017, why? Mantas is the only one group from mobulids which protected in Indonesia since 2014;
Catch per year Mobulids fishery record How the trend of mobulids fishery since intervention? A) Manta birostris catch trend per year in 2015-2017 B) Generalised linier model (GLM) 300 250 200 argeted Bycatch Catch trend per year of M. birostris after intervention 150 100 50 0 2015 2016 2017 he landing trend of targeted fishery is significantly decrease by 97% in 2017; Multi-approaches (e.g. law enforcement, and community outreach and empowerment has significantly influence on reducing mantas landing and effort in Lamakera; By-catch is the biggest issue on mobulids fishery right now, although not significantly as a statistic mentioned n(all)~year n(bycatch)~year n(targeted)~year P R O E C E D
Catch per year Mobulids fishery record How the trend of mobulids fishery since intervention? A) Mobula japanica catch trend per year in 2015-2017 300 250 200 150 B) Generalised linier model (GLM) Catch trend per year of M. japanica after intervention n(all)~year N argeted Bycatch O 100 50 0 2015 2016 2017 he landing trend is significantly increase by 623% in 2017; Bycatch from gillnet fishery is the biggest catch contribution; argeted fishery is decrease; Bycatch is easier excuse on mobulids fishery, since quite challenging during law investigation Gillnet operation has overlap by 75% with mobulids habitat (Salim et al in prep) n(bycatch)~year n(targeted)~year P R O E C E D Y E
Catch per year Mobulids fishery record How the trend of mobulids fishery since intervention? A) Mobula tarapacana catch trend per year in 2015-2017 B) Generalised linier model (GLM) 300 250 200 150 100 50 0 Overall, Mobula tarapacana landing is decrease including targeted fishery; argeted 2015 2016 2017 Bycatch has increase by 167% from 2015 to 2017, although not significant as statistically; Bycatch Catch trend per year of M. tarapacana after intervention n(all)~year n(bycatch)~year n(targeted)~year N O P R O E C E D Y E
Conclusion 1. Impact of law for species protection which combined with dedication and passionate in the field on implementing enforcement, outreach, and community empowerment is significantly reduce the illegal manta hunting 2. Bycatch is the biggest issue in these region which need to be addressed right now!