Phase angle as a new independent condition index for fish? Phase angle as a new independent condition index for fish? M. Keith Cox Sitka Sound Science Center Ron Heintz Alaska NOAA Fisheries

Outline Background BIA and phase angle Background BIA and phase angle Objective Objective Experiments measuring fish condition with phase angle Experiments measuring fish condition with phase angle Temporal, spatial and proximate composition data Temporal, spatial and proximate composition data Summary Summary

Bioelectrical impedance analysis = used for 60 years in human health nutrition studies, when applied to fish… Bioelectrical impedance analysis = used for 60 years in human health nutrition studies, when applied to fish… Total Body Water Total Body Protein

Small, portable and easy to use

Take two measurements 1.Resistance (R) 2.Reactance (Xc)

What is Resistance (R)? Resistance (R) (ohms) Definition - dissipation of energy in a conductive medium Definition - dissipation of energy in a conductive medium Physical property of extracellular material Physical property of extracellular material Sensitive to extra-cellular water (ECW) Sensitive to extra-cellular water (ECW) AlV R = ρ ( L/A)

What is Reactance (Xc)? Reactance (Xc) (ohms) Definition - circuit element's opposition to an alternating current Definition - circuit element's opposition to an alternating current Reflective of cell membrane surface area Reflective of cell membrane surface area academic.brooklyn.cuny.edu

What is phase angle? Phase angle – degrees Definition - time delay between a stimulating current and the voltage generated by an alternating current in a conductive medium. Definition - time delay between a stimulating current and the voltage generated by an alternating current in a conductive medium. Reflective of condition Reflective of condition Cell membrane / ECW Cell membrane / ECW

What is phase angle? 1. Lower phase angles appear to be consistent with low reactance and either cell death or a breakdown in the selective permeability of the cell membrane (Schwenk et al., 2000a; Schwenk et al., 2000b). 2. Higher phase angles are consistent with high reactance and large quantities of intact cell membranes and body cell mass (Abu Khaled et al., 1988; Foster and Lukaski, 1996).

Phase angle in human medicine HIV – (Schwenk et al. 2000b; Paton et al. 1998)  High phase angle better health and prognosis  Low phase angle, decreasing progression and survival Chronic kidney disease (CKD) – (Nagano et al. 2000; Maggiore et al. 1996)  Lower phase angle, lower nutritional status and higher stage CKD Anorexia nervosa – (Mika et al. 2004; Nagano et al. 2000)  Phase angle increased and decreased with the nutritional status of patient  Phase angle did not increase due to edema influenced weight gains Age and sex – (Barbosa-Silva et al. 2005)  Compared healthy persons, phase angles changed with age and sex, global conditional index

Objective: Is phase angle reflective of fish condition? Looked at BIA data we had: 1. Brook and rainbow trout – starved and fed 2. Juvenile Chinook salmon – starved and fed 3. Pacific herring – over wintering Then apply data to… Took NPRB data on forage fish, compared phase angles spatially, temporally and with proximate composition

Fed and starved brook and rainbow trout

Fed and starved chinook and spring herring in Sitka Sound Time

Time

Is phase angle reflective of fish condition? Looked at BIA data we had: 1. Brook and rainbow trout – starved and fed 2. Juvenile Chinook salmon – starved and fed 3. Pacific herring – over-wintering Phase angle Better condition

Is phase angle reflective of fish condition? Looked at BIA data we had: 1. Brook and rainbow trout – starved and fed 2. Juvenile Chinook salmon – starved and fed 3. Pacific herring – over-wintering Phase angle Worse condition

Is phase angle reflective of fish condition? Looked at BIA data we had: 1. Brook and rainbow trout – starved and fed 2. Juvenile Chinook salmon – starved and fed 3. Pacific herring – over-wintering Common value of 15 degrees

NPRB Gulf of Alaska forage fish Methods: Forage fish collected (n=481) with a beach seine in bedrock, eelgrass, and kelp habitats in July and September in PWS. Crescent gunnels (Pholis laeta), Saffron cod (Eliginus gracilis), Pacific herring (Clupea pallasii), Walleye pollock (Theragra chalcogramma)

Temporal differences

Pacific herring (n=130)Crescent gunnel (n=112) Saffron cod (n=145) Walleye pollock (n=94)

Pacific herring (n=130)Crescent gunnel (n=112) Saffron cod (n=145) Walleye pollock (n=94)

Spatial Differences

Pacific herring (n=130) Crescent gunnel (n=112) Saffron cod (n=145) Walleye pollock (n=94)

Pacific herring – proximate composition

Walleye Pollock – proximate composition

Summary Phase angle has been used in human medicine with lower phase angles = decreased condition Phase angle has been used in human medicine with lower phase angles = decreased condition Global health index Global health index We found like results with fish in various conditions We found like results with fish in various conditions Found a 15 degree common value Found a 15 degree common value Were able to use phase angle to both temporally and spatially to see differences in condition Were able to use phase angle to both temporally and spatially to see differences in condition Comparing proximate analysis, encountered the same problem as human medicine in determining what exactly phase angle is measuring other than overall condition increases Comparing proximate analysis, encountered the same problem as human medicine in determining what exactly phase angle is measuring other than overall condition increases

Acknowledgements Rudy Liedtke, RJL Systems Rudy Liedtke, RJL Systems JJ Vollenweider, NOAA Fisheries JJ Vollenweider, NOAA Fisheries Kyle Hartman, WVU Kyle Hartman, WVU Scott Johnson Scott Johnson Heather Woody, Sitka Tribe of Alaska Heather Woody, Sitka Tribe of Alaska Joe Margraf, University of Alaska, Fairbanks Joe Margraf, University of Alaska, Fairbanks NOAA Fisheries, Auke Bay Lab NOAA Fisheries, Auke Bay Lab North Pacific Research Board North Pacific Research Board Exxon Valdez Oil Spill Trustee Council Exxon Valdez Oil Spill Trustee Council

Questions?