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Post-Release Survival of Blue Marlin

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Post-Release Survival of Blue Marlin Post-release Survival of Blue Marlin Mike Musyl, Chris Moyes, Rich Brill, Andrew West John Sibert, Anders Nielsen, & Lianne McNaughton Our goals were: 1. Assess the survival blue marlin released from sports fishing. 2. Develop biochemical predictors of survival. 3. Assess factors affecting post- release survival. PSATs can be used to determine mortality by examination of vertical data. PSATs jettison from fish under three circumstances: 1. Reach programmed pop-off date. 2. Exceed depth threshold (1200 – 1500 m). 3. Remain at constant depth for 4 days. Can differentiate “dead” from “shed”. Mortality of a Blue Shark (Prionace glauca) 0 30 200 25 400 20 600 15 800 10 1124m Fail safe mechanism jettisons 1000 PSAT after reaching 1200m 5 1200 0 4/11/01 4/12/01 4/12/01 4/14/01 4/14/01 4/14/01 4/16/01 Depth (m) Temperature (oC) Swivel to reduce torque of tag head in tissue Speargun barbs added to increase surface area PSAT 37 blue marlin (100-500 lbs) tagged in Hawaii 2 striped marlin (120 lb) tagged in Hawaii 1 black marlin (1000 lb) tagged in Australia fight times: 5 - 60 min 16% on bait, 84% on lures Results to date 30 tags reported data (79%) 8 tags failed to report (21%) 4 tags reached pop-off date (13%) Evidence for delayed mortality in one blue marlin Species Number Tagged No. Reporting Total Days at Mean *No. Waiting (%) Liberty (Range) Blue Marlin 37 28 2140 76 (Makaira nigricans) *1 (78%) (1-245) Black Marlin 1 1 64 64 (Makaira indicus) (100%) Striped Marlin 2 1 12 12 (Tetrapturus audax) *1 (100%) Blue marlin movement patterns First Quarter Full Moon 0 50 ) m ( 100 h t p e D 150 200 7/24/2003 7/25/2003 7/26/2003 7/27/2003 7/28/2003 7/29/2003 0:00 0:00 0:00 0:00 0:00 0:00 Hawaii Standard Time Hourly Depth Preferences 60 50 ) m 40 ( h t p 30 e D . 20 g v 10 A 0 14:00 17:00 20:00 23:00 2:00 5:00 8:00 11:00 Hawaii Standard Time Full Moon First Quarter New Moon 0 30 50 25 ) 20 C o ) 100 m ( 15 ( h t p p 150 m e 10 e D T 200 5 250 0 6/5 6/25 7/15 100 90 80 70 60 50 40 e Day Time at depth m 30 i T 20 l summaries 10 ta o 0 T f 100 o t 90 n e 80 c r 70 e P 60 50 40 30 Night 20 10 Blue Marlin 0 Striped Marlin 10.5-50 50.5-100 100.5-150 150.5-250 250.5-350 Black Marlin Depth (m) Depth distribution of blue marlin tracked near Hawaii using acoustic telemetry. Depth distribution of Day blue marlin tracked near Hawaii using acoustic telemetry. 100 90 80 70 60 50 Night 40 30 Day 20 10 0 100 90 80 70 60 50 40 30 20 Night 10 0 10.5-50 50.5-100 100.5-150 150.5-250 250.5-350 Depth (m) Blue marlin movement patterns Evidence for delayed mortality in Blue marlin after 82 days Deployed Caught on live bait 7 June 2003 Approx. 25 minutes of fight time 130 lb monofilament test line Hooked corner mouth Moved almost due South Pop-off 855 nmi (7.6 nmi /day) 29 September 2003 Evidence for delayed mortality in Blue marlin after 82 days 0 35 200 30 400 25 20 600 15 800 10 Fail safe mechanism jettisons 1000 PSAT after reaching 1200m 5 1200 0 7/7 7/17 7/27 8/6 8/16 8/26 9/5 9/15 9/25 Max. Depth (m) SST Min. Temp. SSuummmmaarryy • 29 of the 30 tags reporting data indicate post- release survival (i.e., only one mortality). • Fail-safe mechanism worked as expected. • Unlikely that mortality after 82 days was the result of the initial insult. Previous studies investigating post-release survivability in marlin using PSATs Graves et al. 2002. Fish. Bull. 100:134-142. • 9 blue marlin tagged in Atlantic • Estimated sizes: 150- 425 lbs. • Caught marlin on lures and bait • Pop-off times set at 5 days • 8 survived • Fate of one tag unknown • No evidence of mortality Kerstetter et al. 2003. Fish. Bull. 101: 939-948 9 blue marlin tagged in Atlantic Estimated sizes: > 100 lbs. Caught on longlines Pop-off times set at 5-30 days 7 survived Fate of two tags unknown No evidence of mortality Gunn et al. 2003. Mar. FW Res. 54: 515-525 • 7 black marlin tagged in Coral Sea • Estimated sizes: 200-600 lbs. • Caught on live and dead bait • Variable pop-off dates (4 days – 5 months) • 5 of 7 survived for 3 – 64 days • Fate of 2 tags was unknown • No evidence of mortality Domeier et al. 2003. Mar. FW Res. 54: 435-445 • 80 striped marlin tagged near Baja California • Estimated sizes: 90-188 lbs • Caught on live bait using circle & J-hooks • 45 fish survived • 16 of 61 fish (26%) died within 5 days • Fate of 19 tags unknown Blue marlin show a huge increase in blood lactate Blue shark Blue marlin 100 5 Lowest marlin lactate is close to the highest shark 80 4 lactate level 60 3 2 40 1 20 0 0 Lactate Hsp70 mRNA Survivor Moribund Unknown Mahalo’s to: •Jody Bright & Crew of Tropidilla Productions •Roy Morioka, PORF, HIBT •Peter Fithian, PORF, HIBT •John Sibert, PFRP •Pacific Islands Fisheries Science Center •Chris Boggs, Mike Laurs, Sam Pooley, NOAA •CABO Yachts and the Captains and Crew who Deployed PSATs: Camelot Foxy Lady Happy Times Holly Ann Ho’okele Ihu Nui Jacque Apito Linda Sue Maui Jim Pacific Blue Pamela Start Me Up Again Top Shape Blue sharks Four parameters show clear differs between survivors & moribund Survivor Moribund Unknown 5 2.0 4 1.5 3 1.0 2 0.5 1 0 0 K+ Mg2+ Lactate Hsp70 mRNA K+ shows much greater increases in marlin Blue shark Blue marlin Mg+ increases ~50% Mg+ increases ~400% 2.0 40 35 1.5 30 25 1.0 20 15 0.5 10 5 0 0 K+ Mg2+ Survivor Moribund Unknown Blue marlin show greater Hsp70 induction Blue shark Blue marlin Hsp70 increases ~3-fold 14 Hsp70 increases > 5-fold 5 12 4 10 3 8 6 2 4 1 2 0 0 Lactate Hsp70 mRNA Black marlin movement pattern.
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