Effects of Hypoxia on Ichthyoplankton and Micronekton Communities off the Oregon and

Washington Coasts

Johnson, A., Ciannelli, L., Barth, J., Brodeur, R., and Wakefield, W.

Oregon State University; NOAA Northwest Fisheries

What is Hypoxia?• Hypoxia: DO in seawater drops below 2.0 mg L-1 (1.4 mL L-1)

– Anoxia: DO in seawater is 0 mg L-1

• Caused by increased nutrient enrichment linked to either human activities or the surfacing of nutrient-rich, oxygen-poor deep water driven by ocean circulation patterns seen along eastern boundary currents (Diaz 2001, Grantham et al. 2004).

• Variations in hypoxia occur vertically and horizontally, with the most intense hypoxic waters occurring in deeper water and at the sediment-water interface.

Barth 2008

Dissolved oxygen (ml l-1)

Dep

th (

m)

1950 to 1999

2000 to 2005

2006

N ~ 4000 hydrocasts

Hypoxia History on the Oregon Coast

(Chan et al. 2008)

Cross-shelf DO anomalies (ml l-1)

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1999 2000 2001

2002 2003 2004

2006Glider data: courtesy of Jack Barth

Glider data: courtesy of Jack Barth

Seasonal Variations in Upwelling Index and Hypoxia

• Understand how shallow water hypoxia affects the fish community off Oregon and Washington coasts during early life-stages

• Inform researchers, managers, fishing communities and general public about the ongoing effort made on hypoxia research

Research Goals and Proposed Outcome

Why investigate impacts on pelagic fish larvae and juveniles?

• Change food webs?

• Increase predation risk?

• Reduce encounter rates of food?

• Larvae contribute to economically important commercial adult fisheries

Why investigate impacts on benthic fish larvae and juveniles?

• Increase predation risk?

• Reduce encounter rates of food/Change eating habits?

• Reduce feeding, metabolic rates

• Community shifts?

•Larvae contribute to economically important commercial adult fisheries (i.e. English sole)

• Determine if low DO affects the abundance of fish early life-stages both in and within the immediate vertical and horizontal proximity of the hypoxia zone.

• Determine if low DO affects the behavior of flatfish early life-stages i.e. a) reaction distance, b) swimming speed, c) distance moved and d) swimming duration.

• Determine if low DO affects the diet of fish early life-stages both in and within the immediate vertical and horizontal proximity of the hypoxia zone.

• Determine if low DO affects the feeding intensity and body condition index of fish early life-stages both in and within the immediate vertical and horizontal proximity of the hypoxia zone.

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Sampling 2008

Longitude (W)

Latit

ude

(N)

Newport

Columbia R.

Lincoln City

Yachats

CH

LB

NH

SRWK

SH

MultinetBeam TrawlMethot

2008 Sampling Efforts 2009 Sampling Efforts

2008 & 2009 Sampling Gear

Common Species in 2008 & 2009

2008 n(n/ total

catch)*100 2009 n(n/ total

catch)*100

Sebastes spp. 67 42.23 Lyposetta exilis 35 49.30

Stenobrachius leucopsarus 15 9.67 Sebastes spp. 9 12.68

Artedius fenestralis 11 7.10 Liparis fucensis 5 7.04

Liparis fucensis 8 5.16 Artedius harringtoni 4 5.63

Engraulis mordax 8 4.76 Pleuronectid 4 5.63

Lyposetta exilis 5 2.98 Isopsetta isopsis 3 4.23

Isopsetta isolepsis 3 1.94 Artedius fenestralis 2 2.82

Pleuronectid 3 1.94Psettichthys melanostictus 2 2.82

Radulinus asprellus 3 1.94 Artedius lateralus 1 1.41

Artedius harringtoni 1 0.59 Radulinus asprellus 1 1.41

Artedius lateralus 1 0.59

Psettichthys melanostictus 1 0.59

Groupsa: ≤1.7 ml/Lb: 1.7-4.0 ml/Lc: >4.0 ml/L

Figure 2: Sampling sites along NH Line, in green (left); Modified beam trawl (right)

Abundance: On both sample dates, abundance was highest at the tow site of 40 meters depth and gradually decreased as tow depth increased (Figure 3)

Length: On both sample dates, average length tended to increase with tow depth. Furthermore, the tow site of 40 meters depth saw the greatest spread in lengths of individual fishes (Figure 4)

Escape Frequency: On both sample dates, escape frequency increased as tow depth increased (Figure 5)

Figure 1: DO levels, 1950-2006 on Oregon’s coast (Chan et al, 2004)

Figure 3: Abundance of fish plotted against tow location and DO levels for July 26th (left) and August 11th (right).

Figure 4: Average length of fish plotted against tow locations and DO levels for July 26th (left) and August 11th (center); Distribution of fish lengths at tow locations (right).

Time to React, Endurance and Duration of Reaction: On both sample dates, no clear patterns or trends were observed between these times and their corresponding tow depth or DO levels and ANOVA tests showed no significant difference (Figure 6, p-values given on graphs)

Figure 5: Escape frequency in percent of fish plotted against tow locations and DO levels from July 26 th (left) and August 11th (right).

Figure 6: (Clockwise from top left) Average time to react in seconds plotted against tow location and DO level; Endurance times in seconds plotted against tow location and DO level; duration of reaction in seconds against tow location and DO level.

Behavior: The most common behavior type was “running” followed by “hopping,” though no relationship seen among behaviors, tow locations or DO levels (Figure 7)

Figure 7: Combined frequency of all behaviors for both dates at all tow locations and at all DO levels (left); percentage of each behavior type at each tow location with corresponding DO levels (right).

Figure 8: endurance times against grouped DO levels

Figure 9: physical samples from beam trawl tows

Timeline•Start: March 2008

•Duration: 3 years

•Field seasons: summer 2008, 2009 and 2010

•Synthesis: 2010

•Personnel involved:PhD: Angela Johnson, Dafne Eerkes-MedranoPIs: Waldo Wakefiled, Ric Brodeur, Lorenzo Ciannelli, Jack BarthSummer REU: Kiva Oken (2008), Natalie Ehrlich (2009)Lab tech: Jessica Rhodes (2009)Rotational NOAA: Chris Toole

1: we only plan to conduct two years of sampling, ideally during the first two year of the study. However, a third year of sampling may be needed if the ne cessary hypoxia conditions are not established or if we do not achieve a satisfa ctory sampling coverage during one of the first two years. 2: Publication of results in peer -reviewed journals will continue after the end date of the proposal.

Project activities Initiation date Completion date Project start date March 2008 Graduate student enrolled in the program March 2008 First year field collections1 May 2008 Sept 2008 Present at the Fall PISCO meeting Sept 2008 Graduate student course-work, year 1 Sept 2008 May 2009 Gather and sort historical fish collections Dec 2008 April 2009 Process first year collections Sept 2008 April 2009 Initiate morphometric and diet analysis Jan 2009 April 2009 Initiate data analysis Jan 2009 May 2009 Present preliminary results to SAFE April 2009 Second year field collections1 May 2009 Sept 2009 Initiate student thesis preparation Sept 2009 Present at the Fall PISCO meeting Sept 2009 Graduate student course-work, year 2 Sept 2009 May 2010 Process second year collections Sept 2009 April 2010 Complete diet and morphometric analysis Jan 2010 June 2010 Continue and complete data analysis Dec 2009 Dec 2010 Present results of the study to SAFE Jan 2011 Continue student thesis preparation Jan 2011 Dec 2011 Publication of results2 Dec 2010 Dec 2011

Table 3. Timeline of the proposed activities.

1: we only plan to conduct two years of sampling, ideally during the first two year of the study. However, a third year of sampling may be needed if the necessary hypoxia conditions are not established or if we do not achieve a satisfactory sampling coverage during one of the first two years. 2: Publication of results in peer -reviewed journals will continue after the end date of the proposal.

Project activities Initiation date Completion date Project start date March 2008 Graduate student enrolled in the program March 2008 First year field collections1 May 2008 Sept 2008 Present at the Fall PISCO meeting Sept 2008 Graduate student course-work, year 1 Sept 2008 May 2009 Gather and sort historical fish collections Dec 2008 April 2009 Process first year collections Sept 2008 April 2009 Initiate morphometric and diet analysis Jan 2009 April 2009 Initiate data analysis Jan 2009 May 2009 Present preliminary results to SAFE April 2009 Second year field collections1 May 2009 Sept 2009 Initiate student thesis preparation Sept 2009 Present at the Fall PISCO meeting Sept 2009 Graduate student course-work, year 2 Sept 2009 May 2010 Process second year collections Sept 2009 April 2010 Complete diet and morphometric analysis Jan 2010 June 2010 Continue and complete data analysis Dec 2009 Dec 2010 Present results of the study to SAFE Jan 2011 Continue student thesis preparation Jan 2011 Dec 2011 Publication of results2 Dec 2010 Dec 2011

Timeline of the proposed activities.

• Acknowledgements:– Oregon Sea Grant– Elakha crew: Mike Kriz, Rick Plummer, Andy

Kriz– NOAA Northwest Fisheries Hake Cruise: Liz

Clark, Dezhang Chu, Steve de Blois, Steve Pierce, & Miller Freeman Crew

– Natalie Ehrlich, Chris Toole, Dafne Eerkes-Madrano, Bobby Ireland, Jason Phillips, Valerio Bartolino, Kiva Oken, Jessica Rhodes