rates of Alaskan shallow - water flatfish species Tom Hurst, - - PowerPoint PPT Presentation

Temperature-dependent growth rates of Alaskan ‘shallow-water’ flatfish species

Tom Hurst, Michele Ottmar, Cliff Ryer Fisheries Behavioral Ecology Program Alaska Fisheries Science Center NOAA-NMFS Newport, OR

Fla latfi fishes in in Ala laska

• 24 Species recorded in Alaskan waters
• ~ 15 species common in Gulf of Alaska and/or Bering Sea
• 14 species commercially harvested
• 2011 – 2015 average

> 250,000 MT/y ~ $225 M/y

• Most important species

Yellowfin sole – largest landings of any flatfish in world Rock sole (northern + southern) – second largest landings Pacific halibut – most valuable – over $130 M/y commercial + important recreational + subsistence fisheries

Compiled from: Mecklenburg et al. 2002. Fishes of Alaska NOAA Commercial fishery statistics website NMFS 2014. Fisheries economics of the United States

Sp Specie ies dis istrib ibutio ions – “shallow water complex”

Northern rock sole Yellowfin sole Pacific halibut Alaska plaice English sole Longhead dab Adult distributions from Matarese et al. 2003 LHD distribution from Mecklenburg et al. 2002 All six species reside in shallow coastal nurseries as juveniles.

Temperature-dependen dependent t growt

• wth

h rat ates es.

Temperature-dependent growth rates of juveniles measured by Ryer, Hurst, & Boersma. 2012

Northern rock sole Pacific halibut English sole

Temperature

5 9 13 16

Specific growth rate

0.00 0.01 0.02 0.03

NRS PH ES

Objectives:

Measure temperature-dependent growth rates of Yellowfin sole Alaska plaice Longhead dab Compare thermal responses among 6 Alaskan flatfishes Contrast yellowfin sole and northern rock sole thermal sensitivity, habitat, distribution, and climate responses.

Fish ish coll llectio ions

Collection locations: YFS: Kodiak, AK AKP: Nome, AK LHD: Nome, AK NRS: Kodiak, AK PH: Kodiak, AK ES: Newport, OR Fish collected from nearshore waters 3-20 m depth Otter trawl & beam trawl Held for several days at collection site Overnight shipment to AFSC laboratory

• n campus of OSU in Newport, OR

Exp xperim imental l facilit ilitie ies

Because of logistical constraints associated with fish numbers and quarantine requirements for some species, we had to do experiments in two different sets of tanks. “large” round tanks, n=15 Used for: NRS, PH, ES, LHD Used for: YFS, AKP, PH Crossover: LHD measured in tanks used for earlier studies Additional PH expt in small tanks at 9°C “small” rectangle tanks, n=32

Exp xperim imental l protocols ls

Tank mean growth rates used in all analyses Number of independent tanks = 10-16 per species Fish acclimated to laboratory culture for at least 2 months prior use in experiments. Extended low temperature range to 2°C for AKP, YFS, LHD. Fish acclimated to test temperatures at approx. 1.5°C / day Acclimated for 2 weeks prior to measuring growth rates. Fish fed ad libitum once per day; “gel food” Measured 3-5 times at 2 week intervals Individual fish identified through size-rank differences except YFS & Supplemental PH experiment; RFID PIT tags in body cavity Analyses based on tank mean growth rates

Growth and su surviv ival

Temperature (°C)

2 5 9 13 16

Specific growth rate

0.000 0.005 0.010 0.015

Survival % 20 40 60 80 100 Temperature (°C)

2 5 9 13 16

Specific growth rate

0.000 0.005 0.010 0.015

Survival % 20 40 60 80 100 Temperature (°C)

2 5 9 13 16

Specific growth rate

0.000 0.005 0.010 0.015

Survival % 20 40 60 80 100

High survival to temperatures where growth drops off. Survival declined above temperature of maximum growth. Low survival at temperatures above 10°C, but surviving fish had high growth. *Not size-dependent. Alaska plaice Yellowfin sole Longhead dab

Temperature

5 9 13 16

Specific growth rate

0.00 0.01 0.02 0.03

NRS PH ES

Co Comparis ison growth th rates patterns across stu tudie ies

Temperature

2 4 6 8 10 12 14 16

Specific growth rate

0.000 0.005 0.010 0.015

AKP YFS LHD

Ryer et al. 2012.

See generally similar patterns. Extended experiments to lower temperatures. Stronger effects observed at the highest temeratures.

Co Comparis ison growth th rates patterns across stu tudie ies???

Are there methodological differences that can explain the lower rates observed in the current study.

Temperature

2 4 6 8 10 12 14 16

Specific growth rate

0.00 0.01 0.02 0.03

AKP YFS LHD NRS PH ES

But overall slower growth observed in AKP, YFS, LHD than NRS, PH, ES

0.000 0.005 0.010 0.015 0.020 0.025

Hali libut exp xperim iment comparis ison

An experiment on juvenile halibut conducted in 2016, at the same time as the YFS experiment allowed us to evaluate the potential for procedural differences between experiments.

Ryer et al. 2012 tested 5, 9, 13, 16° “large” round tanks 7 fish per tank not tagged mean 69.5 mm TL Hurst and Planas, unpublished* tested 2 and 9°C “small” tanks 5 fish per tank internal RFID tags mean 66.7 mm TL < 10% difference in SGR

Growth at 9°C

*Talk by Planas and Hurst, Tuesday 11am.

Fish length (mm TL)

40 50 60 70 80 90 100

Maximum growth rate (SGR)

0.010 0.015 0.020 0.025 0.030 0.035 0.040

Siz Size effects?

LHD 16° AKP 13° YFS 13° PH 16° ES 16° NRS 13°

Not enough size variation within each experiment to describe size-dependent variation in growth. But, likely not enough to be responsible for the observed differences in measured rates.

Fish length (mm TL)

40 50 60 70 80 90 100

Maximum growth rate (SGR)

0.010 0.015 0.020 0.025 0.030 0.035 0.040

Siz Size effects? Age effects ts?

Age 0 Age 1 But, because of differences in the timing of spawning and settlement: NRS, PH, ES were collected as age-0 AKP, YFS, and YFS were collected as age-1 Is there an age effect on growth potential, independent of the general decline in SGR with increasing size. H0: age-0 (pre-first winter) fish are “different” than age-1 (post-first winter)?

LHD 16° AKP 13° YFS 13° PH 16° ES 16° NRS 13°

Similar patterns observed among juvenile gadids.

Laurel et al. 2016

Temperature of maximum SGR

12 13 14 15 16 17

Delta T 50% SGR

4 6 8 10 12

NRS AKP LHD YFS ES PH

Co Comparin ing temperature se sensit itiv ivit ity among sp specie ies

Calculate temperature of maximum SGR Calculate temperature range to 50% SGR

Temperature (°C)

2 4 6 8 10 12 14 16

Specific growth rate

0.000 0.005 0.010 0.015

Relative growth rate

0.0 0.2 0.4 0.6 0.8 1.0

Delta T Eurythermic Stenothermic LHD Representative? High mortality at these temps.

Im Impli licatio ions for r cli limate change

The “Blob” – extensive area of warm waters

• ver the N. Pacific & Bering Sea

Yellowfin sole may be most sensitive to climate change because of their high thermal sensitivity.

Temperature of maximum SGR

12 13 14 15 16 17

Delta T 50% SGR

4 6 8 10 12

NRS AKP LHD YFS ES PH

Already have field evidence of sensitivity.

In Interannual vari riatio ion in in growth refle lects thermal l se sensit itiv ivit ity

Matta et al. 2010. MEPS. Collected NRS, AKP, and YFS from Bering Sea where the species distrubutions overlap. Look at synchrony and climate drivers of annual growth rates. Otolith ring width index based on within individual, across year variation.

Temperature of maximum SGR

12 13 14 15 16 17

Delta T 50% SGR

4 6 8 10 12

NRS AKP LHD YFS ES PH

Eurythermic Stenothermic What about other parts of the distribution?

Matta et al. 2010. MEPS.

Yellowfin sole Northern rock sole

Nort rthernmost range

General models would predict that warming would allow northern rock sole to expand farther north, occupying waters currently inhabited by YFS and AKP. But, coastal temperatures do not follow latitudinal trends. Warming may reduce habitat suitability for the high latitude species even in the northern part of their range.

X

Temperature (°C)

2 5 9 13 16

Specific growth rate

0.000 0.005 0.010 0.015

Survival % 20 40 60 80 100

Su Summary ry

Differences among species in thermal sensitivity. YFS have high thermal sensitivity and live in the most thermally variable environments. Growth responses did not match survival patterns in LHD. YFS will be more sensitive to climate changes. Climate change may alter habitat use throughout their range. Future:

• 1. Repeat experiments across ages to clarify size and age effects.
• 2. Perform temperature preference experiments

– link performance to preference.

• 3. Spatially explicit model of seasonal growth potential.

Broader: Explore how to integrate field and laboratory studies to improve understanding of climate and habitat interactions on fish distributions and productivity.