What`s Up With Halibut?

What’s Happening With Halibut?
Atlantic Halibut Management and Research on the Scotian
Shelf and Southern Grand Banks
Nell den Heyer, Shelley Armsworthy, Sean Smith,
Scott Wilson, Gabrielle Wilson, Kurtis Trzcinski
FSRS AGM 2014
Truro, Nova Scotia
Fisheries and Oceans
Canada
Computer generated native distribution map of
Atlantic Halibut (Hippoglossus hippoglossus).
From FishBase Jonathon Ready, 2009-02-05
Management Unit 3NOPs4VWX5z
Scotian Shelf and Southern Grand Banks
4Vn
3Ps
3O
4V
5Zc
4W
4X
3N
*2013 Landings are incomplete
From DFO 2013
2009 Atlantic Halibut Assessment Model
Length-based age-structured model
Data Inputs

4VWX Summer RV survey: index of recruitment,
1970-present

DFO-Industry Halibut Survey Catch: index of
exploitable biomass, 1998-present

Landings

Length data from Observers, Port Sampling,
Commercial Index fishing

Growth model
2009 Model
Results
From Trzcinski et al. 2011
Stock Status Update
Commercial Index
From DFO 2013
Halibut Survey
50 Stations
Halibut Survey
GLM
Stock Status Update
From DFO 2013
Life History of
Pacific Halibut
Pelagic stage
6-7 months
Sexually Dimorphic
Females larger than males
Males mature app 5-6 yrs (77cm)
Females mature app 9-10 yrs
(119cm)
Adults
Deep water channels and shelf
edge
Typically 250 – 1250 m
Spawning
winter
from Trumble et al. 1993
Industry-DFO Research Projects
 Aging
 Growth
 Halibut All Sizes Tagging (HAST)
 Natural and fishing mortality
 Movement and distribution
 Population size
 Pop-up Satellite Archival
Transmitting (PSAT) tags
 Habitat
 Spawning
Aging
 2400 thin-sectioned
otoliths
 otter trawl, research
vessels, and long line
 1962 to 2007
 validation of 13 with
bomb-radiocarbon
signature
From Armsworthy and Campana 2010
Counting the Years…
Age = 30
3
8
Gear selectivity?
250
250
Males
200
Females
150
Length (cm)
200
Longline
100
150 Longline
100
50
50
Trawl
0
Trawl
0
2
6
10
14
18
22
Age (years)
26
30
2
6
10
14
18
22
26
30
37
Age (years)
From Armsworthy and Campana 2010
Change over time?
250
250
Females trawled
Males trawled
200
Length (cm)
200
150
100
Historic
150
100
50
Historic
50
Recent
0
Recent
0
2
4
6
8
10
12
Age (years)
14
16
18
2
4
6
8
10
12
14
Age (years)
From Armsworthy and Campana 2010
Growth Curves
Females
Males
250
200
200
Length (cm)
250
150
100
50
0
0
10
20
Age (years)
150
Both gears
Linf = 206
K = 0.10
T0 = 0.12
R2 = 0.69
n = 1343
30
Both gears
Linf = 132
K = 0.20
T0 = 1.1
R2 = 0.49
n = 892
100
50
0
40
0
10
20
30
Age (years)
From Armsworthy and Campana 2010
40
50
Halibut All Sizes Tagging
(HAST)
Traditional t-bar anchor or
“pink” tagging
 Estimate natural and
fishing mortality
 Describe movement and
distribution
 Estimate population size
Releases
HAST Methods
 Halibut Survey
 All sizes
 Double tagged
 Proportional to
abundance
Recaptures
 Rewards for returns
 2006, 2007, 2008,
2010, 2012 ….
From den Heyer et al. 2012
Mark-Recapture Analysis
Number of halibut recaptured and released by year of release
and year of recapture. Only halibut 81 cm or greater at time of
tagging and release.
Year
Num
Released Released
Year Recaptured
Total
2006 2007 2008 2009 2010 2011 2012
2006
422
2007
540
2008
549
2010
512
2012
509
Total
2532
15
15
2013
37
20
12
9
7
7
2
109
12
88
36
19
7
9
6
177
16
43
26
10
17
8
120
16
33
39
15
103
10
16
26
82
47
535
49
124
91
70
From den Heyer et al. 2012
57
Multi-year incomplete mixing model
From DFO 2013
Movement
N
Median = 27 km
3000
2500
Distance, km
W
E
2000
1500
S
1000
500
0
0
500
1000
Days at Large
1500
2000
From den Heyer et al. 2012
Pop-up Satellite Archival Transmitting
(PSAT or pop-up tags)
 Light
 Temperature
 Depth
Armsworthy et al 2014
Pop-up Satellite Archival Transmission
(PSAT or pop-up tags)
17 large (118 - 188 cm) halibut
Released between 2007 and 2010
From Armsworthy et al 2014
Habitat
From Armsworthy et al 2014
Spawning Rises
From Armsworthy et al 2014
Spawning Rises
From Armsworthy et al 2014
Ongoing Projects
 2014 pink tagging
 PSAT tags to estimate initial tagging mortality (81
& 118 cm)
 3NOPs4VWX5Zc Assessment Model
 Maturity
Also…
Tagging Atlantic Halibut in Gulf of St. Lawrence and
Iceland
Male Halibut Maturity Stages
•
•
•
Stage 1: Immature (Maturity Code 1)
Stage 2: Mature (Maturity Code 3)
This halibut will not participate in the next spawning season.
This halibut will participate in the next spawning.
The edges of the paired organs are smooth with no crenellations.
Testes very small (usually < 5 cm across).
Firm-textured.
•
•
•
Testes have corrugations (ridges and grooves).
Soft, plump, and swollen in appearance.
If sperm is detectable, the fish is mature.
Stage 3: Spawning (Maturity Code 5)
This halibut is spawning.
•
•
•
Testes are large, have corrugations (ridges and grooves).
Soft, plump, and swollen in appearance.
Milt flows freely at touch.
NOTE TO OBSERVERS
Visual characteristics of maturation stages vary
between geographic locations and season. You
may experience gonads that are between stages.
If a gonad has multiple characteristics in different
stages, choose the stage that has the most
characteristics. DO NOT FORCE A GONAD
INTO A MATURITY STAGE IF YOU ARE
UNSURE. It is important to realize that coding a
fish as immature verses mature is an important
piece of data for stock assessment.
Female Halibut Maturity Stages
Stage 1: Immature (Maturity Code 1)
Stage 2: Pre-spawning (Maturity Code 3)
This halibut will not participate in the next spawning season.
This halibut will participate in the next spawning.
•
•
•
•
•
Ovaries small and firm, tightly
packaged.
Slight development of capillaries.
Oocytes not visible to naked
eye. May see white dots or a
grainy appearance in the internal
membrane.
Membrane extremely thin.
•
•
•
•
•
•
•
•
•
•
•
•
Ovaries reddish with numerous
blood vessels.
Blood vessels/capillaries well
developed and functional, form
elaborate branches and are
usually purple in color.
Membrane thin and translucent
Ovary larger than Stage 1.
Eggs are not extruded with slight
pressure.
Eggs visible to naked eye.
Eggs opaque in color (“Cream of
Wheat” appearance); small
percentage may be clear.
Stage 3: Spawning (Maturity Code 5)
Stage 4: Post-spawning (Maturity Code 6)
This halibut is spawning.
This halibut has recently spawned and is preparing to return to Stage 2.
Ovaries large and swollen.
Membrane thin and translucent.
Eggs flow freely with slight or no
pressure to the ovaries.
Well developed vascular system.
Most eggs are clear.
Eggs large, fully developed
(diameter 3 – 4 mm).
•
•
•
•
•
Gonad flabby, baggy, and
collapsed.
Membrane thick and opaque.
Blood vessels large and deflated
Resorbing eggs may be present.
Early egg development may also
be present. Check membrane
thickness and capillary
development to confirm stage.
Code as Stage 2 if eggs are
opaque.
Acknowledgements
 Halibut fishermen
 Eastern Shore Fisherman's Protective
Association
 Shelburne County Quota Group
 Atlantic Halibut Council
 Javitech
 Tara MacIntyre, Megan Vaughn, Lenore Bajona,
Shelley Bond and Jerry Black