Sex-biased movement of Atlantic halibut on Scotian Shelf and - PowerPoint PPT Presentation

Sex-biased movement of Atlantic halibut on Scotian Shelf and southern Grand Banks …but first, why we are interested in that… Nell den Heyer , K. Ransier and N.L. Shackell Fisheries and Oceans, Canada IFS Nov 2017 1

Large, long-lived and sexually dimorphic 250 250 Females Males 200 200 150 150 Both gears Both gears 100 100 L inf = 132 L inf = 206 K = 0.20 K = 0.10 T 0 = 0.12 T 0 = 1.1 50 50 R 2 = 0.49 R 2 = 0.69 n = 1343 n = 892 0 0 0 10 20 30 40 0 10 20 30 40 50 Age (years) Age (years) From Armsworthy and Campana 2010 2

Managed as two separate stocks: Gulf of Saint Lawrence Scotian Shelf & Southern Grand Banks (Newfoundland ) Newfoundland 3L Overseas France 5Y Both are experiencing a period of high juvenile recruitment 3

2015 Value of Commercial 2015 Value of Commercial Groundfish Groundfish Canada = $362 Million Atlantic Canada = $216 Million Greenland halibut Greenland halibut Atantic halibut Atlantic halibut Pacific halibut Haddock Flatfishes Atlantic Cod Redfish spp. Redfish spp. Haddock Cod Flatfishes Other Other 30 Total Legal Spawning 25 Biomass, 1000t 20 Halibut survey biomass index 15 10 5 0 1970 1976 1982 1988 1994 2000 2006 2012 Year 4

Canadian and foreign landings Some of this is Greenland halibut 5

http://www.photolib.noaa.gov/700s/figb0010.jpg FISHING HISTORY • <1700’s-early 1800’s Halibut=NUISANCE in US Cod fishery (not easy to salt) Train system improves in early 1800s providing …not so heavily fished easier access to Ice US fishermen predominate. Canadians not in until 1900s Commercial fresh fish on ice 1836 L overfished 1880= L Collapse -Head to Canada under Treaty of Paris (1783) By 1850 6 L overfished By 1850 L overfished

Atlantic Halibut Research History 50s and 60s: tagging Pacific Halibut 80s: maturity, tagging, yield model è management units, TAC and min size 1998 –present: Industry-DFO halibut longline survey 2003-2007: growth and age-length key 2006-present: conventional tagging 2007,2009,2011&12: PSAT tagging 2010: first age-structured length based assessment model 2014: new assessment framework with MSE approach 2015-present: Spatial ecology 2017-present: Genetics 2017: New Stratified Random Survey from Trumble et al. 1993 7

(Nancy Shackell, Nell den Heyer, Kiyomi French/DFO, Canada) Q: Are the following consistent with current stock unit domain? Size of Juvenile Partial Migration of Connectivity Mature female R Habitat ~ Adult Life history trait Current=2000km; residents: 29 km Estimated=250km landings Winter Migration: <200km A: No… how can this contribute to sustaining stock? -add Spatial Management to Framework Assessment ? Genetic landscape Range expansion/secondary role of closed areas (in progress) MSE by spatial units 8

Halibut all-sizes tagging - “pink” Ø Estimate natural and fishing mortality Ø Describe movement and distribution 9

Counter current migration H1. Juveniles moving farther than adults and from west to east. (larval drift to the west) 10

Sex-biased seasonal movement Residents: less than 20 km Migrants: 20km to 250 km Nomads: 250 km+ Mature males: 80cm+ Mature females: 103cm+ (4X), 119cm+(3NOPS4VW) Summer: April to August Winter: September to March H2 Movement varies by sex and season 11

Halibut all-sizes tagging § Over 4500 halibut tagged since 2006 § Double tagged to estimate tag loss § During halibut longline survey in May-July § Tag allocation by NAFO area proportional to abundance § All sizes – fishermen compensated for release of legal fish § Rewards for returns – AHC $100 reward per fish (with one or two tags) plus chance to be chosen in a quarterly draw for $1000 12

N=4559 13

n=4559 n=811 n male = 261 n female = 302 n=811 n male = 261 n female = 302 14

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Residents Migrants Nomads Year <20km 20km-250km >250km 0 48 46 3 1 128 99 33 2 74 76 20 3 46 33 17 4 21 28 16 5 13 19 10 6 12 12 7 7 6 19 4 8 6 3 5 9 0 1 3 10 2 1 0 Total 356 337 118 Percent 44% 42% 15% 16

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Net distance moved by season, sex and maturity ü For juveniles no difference by sex or season ü Mature females different in winter and summer ü Mature males different from mature females in summer and mature females in winter ü Mature males not different from juveniles Summer Winter Immature ● ● Mature ● ● 18

Immature males and females and mature males Mean squared displacement, km 2 Time between release and recapture, by quarter Year 1 Year 2 Year 3 Year 4 19

Counter current ‘migration’ Juveniles (and mature males) move further than mature females in summer and largest movements biased to east and west 20

Residents Migrants Nomads <20km 20km-250km >250km n Summer Immature_Female 50% 35% 14% 105 Immature_Male 43% 45% 12% 75 Mature_Female 71% 24% 4% 91 Mature_Male 58% 29% 13% 38 Overall 56% 34% 11% 309 Winter Immature_Female 39% 44% 17% 71 Immature_Male 28% 48% 24% 93 Mature_Female 29% 49% 23% 35 Mature_Male 35% 47% 18% 55 Overall 33% 47% 20% 254 21

Median = 5.9 km, mean= 42km 22

Median =80 km, mean= 125 km 23

Pop-up satellite archival transmission (PSAT) tags § 14 successful deployments § Stars indicate deployments with spawning rises From Armsworthy et al. 2014 24

Counter current migration ? ? ? ? Juveniles (and males) move further than mature females in summer and largest movements biased to east and west 25

Conclusions Ø High proportion of halibut are resident, with some being caught up to 10 years after release within 20km of release Ø Large females are more likely to be recaptured within 20km of release in the summer, suggesting established summer foraging areas Ø In winter, large females more likely to move than all other halibut Ø Southern Grand Banks and Gully are potential areas for spawning Ø Juveniles are more likely to move the greatest distances Ø Movement of juveniles and adult males are consistent with diffusion Ø Largest movements along the coast are predominantly from east to west Area-based management, MPA design, spawning stock structure, as well interpretation/application of deployment of satellite tags on large halibut 26

Acknowledgements § Eastern Shore Fisherman's Protective Association § Shelburne County Quota Group § Atlantic Halibut Council § Javitech § K. Trzcinski, S. Armsworthy, G. Wilson, S. Wilson, L. Bajona, M. McMahon, B. Wringe, S. Smith 27

Partial migration a) non-breeding partial migration b) Breeding partial migration c) Skipped breeding partial migration Chapman et al. 2011 28

Percent of those recaptured in NAFO area, by area of release Release Recovery (%) n 0B 3N 3O 3P 4Vn 4Vs 4W 4X 5Y Males 14 3N 0 29 64 7 0 0 0 0 0 3O 13 0 8 62 15 0 8 8 0 0 3P 46 0 0 13 67 2 9 4 4 0 8 4Vn 0 0 0 0 88 13 0 0 0 4Vs 33 0 0 0 9 0 70 21 0 0 43 4W 0 0 0 14 0 14 63 9 0 4X 28 0 0 0 4 0 7 29 61 0 Females 56 3N 0 29 66 5 0 0 0 0 0 3O 26 0 4 73 19 0 4 0 0 0 53 3P 0 2 2 85 0 9 2 0 0 4Vn 3 33 0 0 0 67 0 0 0 0 4Vs 38 0 0 0 11 0 68 21 0 0 28 4W 0 14 0 7 0 14 61 4 0 4X 29 0 0 7 10 0 7 14 55 7 29

Unit Stock …all of this affects all of that-> Adapted from http://www.iiasa.ac.at/web/scientificUpdate/2013/researchProgram/EvolutionandEcology/EvolutionaryConsumption.html 30