Difference of fish behavior associated with drifting FADs by species and oceanographic conditions possibility of selective catch by purse seine fishery Takayuki Matsumoto 1, Keisuke Satoh 1, Yasuko Semba 1, Tatsuki Oshima 2 and Mikio Toyonaga 2 1 National Research Institute of Far Seas Fisheries, Fisheries Research Agency (NRIFSF) 2 Marine Fisheries Research and Development Department Center of Fisheries Research Agency (JAMARC) 1
Contents Backgrounds Distribution of operation and bigeye catch by Japanese purse seine fishery Behavioral study using acoustic telemetry Comparison of fish behavior under different oceanographic conditions Catch rate of bigeye tuna by purse seine under several conditions Future outlook 2
Backgrounds Many small yellowfin and bigeye tunas are caught by purse seine fishery operating around floating objects including FADs, which may have bad effects on the stocks. We conducted research of monitoring fish behavior around FADs using ID pinger to get information for the selective catch by purse seine fishery. Catch rate of bigeye tuna by purse seine fishing gear and operation type was analyzed and considered 3
Distribution of Japanese purse seine operations
Catch of bigeye tuna by purse seine 5
Species composition of catch (based on logbook, tropical area) 1% Proportion of catch in weight 8% 6% % 2% % 199 1995 1996 1997 1998 1999 2 21 22 23 2 25 26 Year 6
Total catch in WCPFC area Data: WCPFC Yearbook 1,, 1,2, 1,, 8, 6,, 2, Totalc atc h (pu rse se ine,w C P F C are a) 7 1967 197 1973 1976 1979 1982 1985 1988 1991 199 1997 2 23 Year 5, Totalc atc h (pu rse se ine,w C P F C are a), 3, 2, 1, Catch(t) 1967 197 1973 1976 1979 1982 1985 1988 1991 199 1997 2 23 Year Catch(t)
Image of tuna association with FAD (virtual) FAD (drifting) Skipjack Yellowfin Bigeye 8
Behavioral study around drifting FAD (21, 23, 25) Capture of the fish (jigging or trolling) Deployment of ID pinger (coded transmitter) Release Monitor the behavior around FADs ID pinger Two successful tracking in 25 No.1 FAD6:, No.2 FAD8:,, 9
Biotelemetry system Hydrophone Sonic signal (ID, depth and position) 51-6kHz 2-69 sec. interval Up to 56 individuals R/V Shoyo-maru Wind direction Distance: usually 25 to 6m Depth 12 to 3m FAD (drifting) Fish with ID pinger (VEMCO V16P-1H, 3H) 1
Summary of successful tracking Tra ck No. FAD No. Period of tracking Duration of tracking (hr) Position of initial release Number of individuals released with ID pinger Size of the fish (cm) (monitored for >2h) 1 FAD6 25/7/9-25/7/21 283 1-.5N 176-2.3E 16 23 26 Total 65 :38.9, :35.8-93.1, 37.7-85.5 2 FAD8 25/8/1-25/8/2 35 5-39.6N 178-5.2E 1 2 6 Total :36.-6., :36.9-91.3,.8-7.3 Total 633 (26d 9h) 3 3 32 Total 15 :36.-6., :35.8-93.1, 37.7-85.5 11
Position of this study Marshall Is. No.2 (FAD8) Gilbert Is. No.1 (FAD6) Phoenix Is. 12
IndividualID 7/9 : 5 1 15 2 25 3 35 5 5 55 6 65 7/1 : Association with FAD for each individual (1 st tracking, FAD6) 7/11 : 7/12 : 7/13 : 7/1 : Tim e (L ocal) 7/15 : 7/16 : FAD6 7/17 : 7/18 : 7/19 : 7/2 : 7/21 : Night 1 232 53.5cm 2 225 2.cm 3 2261 3.6cm 22 3.5cm 5 2252 38.cm 6 2295 2.5cm 7 2253 55.cm 8 597 3.7cm 9 5982 38.9cm 1 229 5.9cm 11 2263 38.cm 12 2262 3.7cm 13 2287 39.6cm 1 232 52.3cm 15 2282 65.cm 16 2268 56.cm 17 2258 33.5cm 18 2259 33.5cm 19 226 35.8cm 2 231 93.5cm 21 2255 35.3cm 22 2256 36.cm 23 235 53.3cm 2 2297 8.7cm 25 2298 85.3cm 26 2299 81.2cm 27 236 83.cm 28 238 59.8cm 29 239 88.cm 3 2312 37.9cm 31 2315 76.2cm 32 2316 71.cm 33 2317 36.8cm 3 2292 93.1cm 35 2269 32.cm 36 283 59.5cm 37 227 33.2cm 38 2271 3.2cm 39 2799 33.8cm 233 37.5cm 1 23 38.3cm 2 2296 38.cm 3 237 37.7cm 23 36.6cm 5 225 38.cm 6 2251 36.8cm 7 2798 39.2cm 8 2313 37.7cm 9 231.cm 5 2318 1.7cm 51 2319 67.cm 52 2288 85.cm 53 2289 75.cm 5 229 77.2cm 55 2291 85.5cm 56 231 57.3cm 57 2293 5.9cm 58 2311 6.5cm 59 2283 7.5cm 6 228 8.8cm 61 2265 36.cm 62 2285 39.5cm 63 28 5.6cm 13 6 287 39.cm 65 2286 33.5cm Release S hedding Skipjack(<cm) Skipjack( cm) Yellowfin(<6cm) Yellowfin( 6cm) Bigeye(<6cm) Bigeye( 6cm) : Release : Shedding : Night
Association with FAD for each individual (2 nd tracking, FAD8) IndividualID 8/1 : 5 1 15 2 25 3 35 8/11 : 8/12 : 8/13 : 8/1 : 8/15 : 8/16 : Tim e (Local) 8/17 : FAD8 8/18 : 8/19 : 8/2 : 8/21 : 8/22 : 8/23 : 8/2 : 8/25 : Night 1 279 39.8cm 2 2791 39.9cm 3 2272 38.1cm 2792 36.1cm 5 2273 38.2cm 6 (<cm) 227 5.9cm 7 2276 38.8cm 8 2277 52.1cm 9 2278 38.6cm 1 285 56.cm 11 ( cm) 289 6.cm 12 2279 5.6cm 13 2281 36.cm 1 2323 5.7cm 15 2267 36.9cm 16 336 6.cm 17 2266 38.6cm 18 226 32.9cm 19 331 38.8cm 2 (<6cm) 335 91.3cm 21 332 36.5cm 22 2322 57.5cm 23 33 59.2cm 2 286 57.2cm 25 2797 38.7cm 26 ( 6cm) 288 56.7cm 27 2796 36.cm 28 3313 79.9cm 29 279 39.6cm 3 281 79.cm 31 2793 2.cm 32 (<6cm) 2795 31.6cm 33 2275.2cm 3 337 63.2cm 35 B ET329 1.6cm 36 B ET282 6.1cm 37 B ET331 7.3cm 38 B ET28.8cm Skipjack Skipjack Yellowfin Yellowfin Bigeye : Release 39 B ET3315 3.2cm : Shedding B ET228 35.cm R elease Shedding 1 : Night
Time series swimming depth (1 st tracking, FAD6) Depth(m ) D epth(m ) 7/13 : 5 1 15 2 25 3 5 1 15 2 25 3 7/13 8: 7/13 16: 7/1 : Ye low fin tuna FAD 6 25/7/13-7/17 7/1 8: 7/1 16: Ship tim e 7/15 : 28 28 28 28 2 2 2 2 2 2 2 2 16 16 16 16 Night12 N ight 12 N ight 12 N ight N ight 7/13 : 7/13 8: 7/13 16: 7/1 : 7/1 8: 7/15 8: 7/15 16: 7/16 : Bigeye tuna FAD6 25/7/13-7/17 7/16 8: 7/16 16: 28 28 28 28 2 2 2 2 2 2 2 16 2 16 16 16 Night12 N ight 12 N ight 12 N ight N ight 7/17 : 3 Ship time 7/1 7/15 7/16 16: 7/15 : 7/15 8: 16: 7/16 : 7/16 8: 16: 7/17 : 3 3 3 2298 85.3cm 2299 81.2cm 236 83.cm 238 59.8cm 2316 71.cm 2317 36.8cm 2292 93.1cm 2799 33.8cm 237 37.7cm 2313 37.7cm 2319 67.cm 2289 75.cm 229 77.2cm 2291 85.5cm 231 57.3cm 2293 5.9cm 2311 6.5cm 2283 7.5cm 15
Depth(m ) Depth(m ) Depth(m) Time series swimming depth (2nd tracking, FAD8) Skipjacktuna FAD8 25/8/19-8/23 Ship time 8/19 : 8/2 : 8/21 : 8/22 : 8/23 : 8/2 : 3 3 3 3 5 1 15 2 25 3 26 26 26 22 26 22 22 18 22 18 18 18 1 1 1 1 12 12 12 12 1 1 Yellow fin tuna FAD 8 25/8/19-8/23 Ship time 8/19 : 8/2 : 8/21 : 8/22 : 8/23 : 8/2 : 5 1 15 2 25 3 3 3 3 3 22 22 22 18 22 18 18 18 1 1 1 1 12 12 12 12 1 1 1 1 1 1 Bigeye tuna FAD8 25/8/19-8/23 Ship tim e 8/19 : 8/2 : 8/21 : 8/22 : 8/23 : 8/2 : 3 3 3 3 3 5 1 15 2 25 3 26 22 18 1 12 1 26 26 26 26 22 22 22 22 18 18 18 18 1 1 1 1 12 12 12 12 1 1 1 1 2281 36.cm 2272 38.1cm 2278 38.6cm 2323 5.7cm 2277 52.1cm 289 6.cm 337 63.2cm 281 79.cm 3313 79.9cm 335 91.3cm 2797 38.7cm 279 39.6cm 336 6.cm 288 56.7cm 286 57.2cm 33 59.2cm 228 35.cm 28.8cm 329 1.6cm 3315 3.2cm 282 6.1cm 331 7.3cm Depth(m) 5 1 15 2 25 FAD8 C T51C 7 6-28.652N,177-17.69W 25/8/2 19:6 Tem perature( ) 5 1 15 2 25 3 35 3..5 1. 1.5 2. 2.5 3. 3.5 DO(ml/l) Tem perature DO 16
Comparison of vertical behavior between species (25 2 nd tracking) FAD8 25/8/2-8/22 m ixed species Ship time 8/2 : 8/2 12: 8/21 : 8/21 12: 8/22 : 3 3 3 5 Depth(m) 1 15 2 26 26 22 22 18 18 1 1 12 12 Night Night 26 22 18 1 12 Night 2277 52.1cm 288 56.7cm 282 6.1cm 17
Frequency distribution of swimming depth for each tracking and species 1 st tracking 5 FAD6 al N=16 5 FAD6 al N=23 5 FAD6 al N=26 Depth(m) 1 15 2 Day 82.9m Depth(m) 1 15 2 Day 85.3m Night 6.m Depth(m) 1 15 2 Day 86.m Night 61.3m 2 nd tracking Sday 5 2 6 N um ber of records FAD8 al 5 1 2 3 N um ber of records FAD8 al N=2 5 2 6 N um ber of records FAD8 al N=6 Snight Depth(m ) 1 N=1 Depth(m ) 1 Depth(m ) 1 Depth (average) 15 2 Day 66.m Night 37.9m 1 2 3 N um ber of records 15 2 Day 8.6m Night 55.5m 5 1 15 Num ber of records 15 2 Day 79.m Night 52.7m 18 1 2 3 5 N um ber of records
Species composition of the catch by jigging by fishing day (1 st tracking) 7/9 7/1 No.1 Tracking (F A D 6) N um ber of individuals(%) % 2% % 6% 8% 1% Fishing day 7/11 7/12 7/13 7/1 7/15 7/16 7/17 7/18 7/19 19
3 25 2 15 1 5 Length frequency of the catch by fishing day Skipjack Yellowfin Bigeye 7/9 3 35 5 5 55 6 65 7 75 8 12 1 8 6 2 7/9 3 35 5 5 55 6 65 7 75 8 85 9 95 1 1 8 6 2 7/9 3 35 5 5 55 6 65 7 75 8 85 9 95 1 2 16 12 8 7/11 3 35 5 5 55 6 65 7 75 8 2 16 12 8 7/11 3 35 5 5 55 6 65 7 75 8 85 9 95 1 2 16 12 8 7/11 3 35 5 5 55 6 65 7 75 8 85 9 95 1 1 8 6 2 7/13 3 35 5 5 55 6 65 7 75 8 1 8 6 2 7/13 3 35 5 5 55 6 65 7 75 8 85 9 95 1 1 8 6 2 7/13 3 35 5 5 55 6 65 7 75 8 85 9 95 1 2 16 12 8 7/15 3 35 5 5 55 6 65 7 75 8 5 3 2 1 7/15 3 35 5 5 55 6 65 7 75 8 85 9 95 1 12 1 8 6 2 7/15 3 35 5 5 55 6 65 7 75 8 85 9 95 1 2 16 12 8 7/17 3 35 5 5 55 6 65 7 75 8 1 8 6 2 7/17 3 35 5 5 55 6 65 7 75 8 85 9 95 1 1 8 6 2 7/17 3 35 5 5 55 6 65 7 75 8 85 9 95 1 N um ber of individuals 1 8 6 2 7/19 3 35 5 5 55 6 65 7 75 8 Fork length(cm ) 1 8 6 2 Number of individuals 7/19 3 35 5 5 55 6 65 7 75 8 85 9 95 1 Fork length(cm ) Num ber of individuals 2 16 12 8 7/19 2 3 35 5 5 55 6 65 7 75 8 85 9 95 1 Fork length(cm )
Day Average depth (m ) Difference of swimming depth by species and size (daily average depth, 1 st tracking, FAD6) 5 1 15 2 25/7/13 D ay 2 6 8 1 Average depth (m ) 5 1 15 25/7/1 D ay 2 6 8 1 Average depth (m ) 5 1 15 25/7/15 D ay 2 6 8 1 Average depth (m ) 5 1 15 25/7/16 D ay 2 6 8 1 25/7/17 D ay 25/7/18 D ay 25/7/19 D ay 25/7/2 D ay 5 1 15 2 6 8 1 5 1 15 2 6 8 1 5 1 15 2 6 8 1 5 1 15 2 6 8 1 Night Average depth (m ) 5 1 15 25/7/13 N ight 2 6 8 1 Average depth (m ) 5 1 15 25/7/1 N ight 2 6 8 1 Average depth (m ) 2 6 8 1 25/7/15 N ight 2 6 8 1 Average depth (m ) 2 6 8 1 25/7/16 N ight 2 6 8 1 25/7/17 N ight 25/7/18 N ight 25/7/19 N ight 25/7/2 N ight 2 6 8 1 12 2 6 8 1 2 6 8 1 2 6 8 1 2 6 8 1 2 6 8 1 2 6 8 1 12 21 2 6 8 1
Day 2 6 8 1 Difference of swimming depth by species and size (daily average depth, 2 nd tracking, FAD8) 25/8/16 Day 2 6 8 1 5 1 25/8/17 Day 15 2 6 8 1 5 1 25/8/18 Day 15 2 6 8 1 5 1 25/8/19 Day 15 2 6 8 1 5 1 15 25/8/2 Day 2 6 8 1 5 1 15 25/8/21 Day 2 6 8 1 5 1 15 25/8/22 Day 2 6 8 1 5 1 15 25/8/23 Day 2 6 8 1 Night 25/8/12 Night 2 6 8 2 6 8 1 2 6 8 25/8/13 Night 2 6 8 1 2 6 8 25/8/1 Night 2 6 8 1 2 6 8 1 25/8/15 Night 2 6 8 1 2 6 8 25/8/16 Night 2 6 8 1 2 6 8 1 25/8/17 Night 2 6 8 1 2 6 8 1 25/8/18 Night 2 6 8 1 2 6 8 25/8/19 Night 22 2 6 8 1
Comparison with 23 study Oct.-Nov. 23, WCPFC SC1 document, Matsumoto et. al. (25) 23
1 Oceanographic condition 23 study C T3237 3.S,176.6E 23/11/3 17: Tem perature( ) 1 2 3 1 25 study (2 nd tracking) FAD8 CT51C7 6-28.652N,177-17.69W 25/8/2 19:6 Tem perature( ) 1 2 3 D epth(m) 2 3 Depth(m) 2 3 5 Tem p DO 1 2 3 DO(ml/l) 5 Tem perature DO 1 2 3 DO(ml/l) 2
Results of 23 study ( and only) FAD7 23/11/8-11/1 m ixed specie s (B E T,Y F T ) aro u n d 3-3 7 S,177-5E Ship time 11/8 : 11/8 12: 11/9 : 11/9 12: 11/1 : 11/1 12: Depth(m ) 5 1 15 2 3 3 3 28 28 28 2 2 2 2 2 2 5981 97.7cm 5963 67.2cm 5969 67.8cm 5965 66.cm 5975 65.cm B ET5967 85.cm B ET5976 71.2cm B ET5979 67.1cm B ET5966 5.cm Night 25 3 25
Comparison of swimming depth between tracking series 23 D epth(m) 3.S,176.6E 23/11/3 17: Tem perature( ) 1 2 3 5 1 15 2 25 3 25 2nd 35 1 2 3 DO(ml/l) 6-28.652N,177-17.69W 25/8/2 19:6 Tem perature( ) 1 2 3 5 Tem p DO Depth(m) 5 1 15 2 25 3 35 5 FAD7 al 5 1 15 Num ber of records FAD8 all Night Day Depth(m) 5 5 1 15 2 25 3 35 FAD7 all 5 1 N u m be r o f re c o rds FAD 8 B ET a l Night Day 1 1 1 Depth(m) 15 2 Depth(m) 15 2 Depth(m) 15 2 25 3 35 Tem perature DO 1 2 3 DO(ml/l) 25 3 35 -day -night 5 1 15 N um ber of records 25 3 -day -night 26 2 6 N um ber of records
The relationship between the length of underwater object of FAD and bigeye catch by purse seine Satoh et. al. (27) (WCPFC SC3 document) Hypothesis: The longer the underwater object of FAD becomes, the more bigeye is caught Methods FAD underwater object length: report by vessels catch: logbook and port sampling 27
Short Floating base Long The length of underwater structures not associated with FADs Catch ratio of :.38 = 5/13 Catch : 13 = 8 () + 5 () associated with FADs Catch ratio of :.5 = 1/2 Catch : 2 = 1 () + 1 () 28
Results Significant correlations were not found Sample size is very small This study is continuing ratio of bigeye tuna to total catch per set.3.25.2.15.1.5. (A) port sampling 2 6 8 ratio of bigeye tuna catch to total catch per set.25.2.15.1.5. (B) log book 2 6 8 Depth of under water structure of FADs (m) Depth of under water structure of FADs 29 (m)
Behavior of fish after setting of the net (virtual) FAD (drifting) 3
Species composition by fishing method (25 1 st tracking) Purse seine operation and on-board sampling were conducted for the same FAD just after the tracking 25 FAD6 species com position of the catch in num ber 25 FAD6 species com position of the catch in weight Fishing m ethod Jigging Fishing m ethod Jigging Purse seine Purse seine % 2% % 6% 8% 1% Proportion in num ber 31 % 2% % 6% 8% 1% Proportion in weight
Difference of catch by time of operation Based on logbook, 1995 - May 27 C atch per set (t) 8 7 6 5 3 2 1 68.8 39. C atch per set by operation time Floating object set N ight (start before 8:) D ay (start after 8:) 12. 1. 11.5 8.1 8. 6.2 >1kg <1kg Species 32
Future outlook Consider the design of future behavioral study Monitoring the behavior of each species after setting the net Difference of horizontal behavior among species Analyze and consider in detail about the effect of gear and operation type for the catch of bigeye tuna 33
Acknowledgements Crew of R/V Shoyo-maru Staffs of Fisheries Agency of Japan Staffs of JAMARC Crew of purse seine vessel No.18 Taijin-maru VEMCO Nippon Kaiyo Co. LTD. PFRP 3