1. Multiple stressor effects in early life stage fish
Adria A. Elskus
U.S. Geological Survey – Aquatic Toxicology Section
University of Maine
NOAA/Maine SeaGrant Atlantic Salmon Workshop
22-23 July 2008

2. Contaminant effects on salmonids as related to tissue residue levels
Triazines Olfaction, Endocrine disruption (ug/L)1 ppb
Triazines+NP Smoltification (ug/L)6 ppb
Organophosphates Olfaction, Homing (ng-ug/L)2 pptr-ppb
Dioxin Visual acuity (100 pg/g egg)3 pptr
Prey capture (300 pg/g egg)3 pptr
Blue sac disease (30 pg/g egg)4 pptr
Adult & fry survival (0.3 pg/g egg)8 pptr
o,p-DDE Immunosuppression (0.5 ug/g lipid)9 ppm
PCBs ~ Sublethal threshold for juvenile salmonids
(2.4 ug PCB/g lipid; ng/g wet)7 ppm, ppb
Methyl mercury Altered feeding (4000 ng/g liver)5 ppb
1Moore&Lower, 2001;2Scholz et al., 2000;3Carvalho & Tillitt, 2004; 4Cook et al., 2003;5Berntssen et al., 2003; 6Moore et al., 2003;7Meador et al., 2002;8Giesy et al. 2002;9Milston et al. 2003

3. Poor marine survival of ATS: Compromised during early life stages?
Hatchery fish ~ compromised due to conditions in the hatchery:
Contaminants in feed10
~ very efficient bioaccumulation/biomagnification (parr broodstock)11
~ remobilized during fasting (e.g. smoltification) to vital organs (brain, liver, kidney)12
~ alter immune function, growth, survival, olfaction 12, 13, 14
~ early life stage exposure alters development of these systems9,14,22
~ additive/synergistic effects of mixtures of chemicals10
~ levels of PCBs in GLNFH salmon (1-3 year olds)21 approaching PCB effects threshold7
Dry food instead of live food
~ prey capture efficiency compromised?
Lack learned behaviors of wild counterparts
~ poor predator avoidance?
Physical environment in hatchery
~ L/D cycles (photoperiod) inconsistent/not ambient?
~ diurnal temperature swings dampened?
~ noise (e.g. low water alarm/CBNFH)
CONSEQUENCES:
MULTIPLE STRESSOR CONDITIONS EXIST IN THE HATCHERIES,
EXPOSURE/STRESS DURING EARLY LIFE STAGES CAN BE MANIFESTED AS COMPROMISED PHYSIOLOGY IN LATER LIFE STAGES
10 Maule et al 2007; 11 Isosaari et al 2004; 12 Jorgensen et al 2002; 13 Maule et al 2005; Jorgensen et al 2004; 21 Millard et al 2004; 22Lerner et al 2007b

4. ‘Wild’ fish ~ compromised due to riverine conditions:
acid, aluminum, pesticides, organochlorines, temperature interactions = multiple stressors
~ olfaction (homing, synchronized mating, detecting mating cues, alarm/predator cues) 15
~ smolting16,23
~ immune competence9
~ ability to mount effective response to stress13
~ survival of adults exposed as parr-smolts17
~ swimming, survival, growth of smolts19
~ early life stage exposure alters development of these systems23
compromised prey? (abundance/timing of arrival/appropriate species composition)
15Moore & Waring 1998; 16Arsenault et al 2004; 17Brown & Fairchild 2003; 19Smith&Haines, 1995; 23Lerner et al 2007a
[Data in graph: 17Jackson, 2003; 18MBPC, 2002; 20Johnson & Kahl, 2005]

5. Hypothesis, Research, Management-1
Hypothesis: Effects on early life stages are not manifested until fish reach transitional life stages (e.g., smolting, SW entry, spawning).
Research Activities: Evaluate effects of early life stage rearing conditions on later life stages (fry, parr, smolts):
A. Compare the effects of the parr-broodstock rearing strategy on contaminant loads and fitness of fry and smolts:
i. Screen: Screen fry and smolts, reared from adult-broodstock and parr-broodstock, for tissue contaminants. Compare contaminant loads to published sublethal thresholds for salmon.
ii. Screen: Screen fry and smolts reared from adult-broodstock and parr-broodstock, for fitness endpoints (e.g. immune competence, critical swimming speed, prey capture efficiency).

6. Hypothesis, Research, Management - 2
B. Compare the effects of eliminating exposure to periodic pulses of acid and aluminum throughout early life stage development
iii. Rear salmon, fertilization through smolts, at the DSF-Pleasant River hatchery with half the water buffered, and half not-buffered (study in progress) and measure fitness endpoints at several life stages.
Strength: isolates acid/Al stress from other stresses.
Drawback: combines river and hatchery stressors.
iv. Temperature-mark DSF fry (from iii. above), release them in the Pleasant River, collect migrating smolts (both hatchery-reared and wild) from the Pleasant River and compare fitness.
Strength: isolates effects of hatchery conditions (e.g. parr-broodstock rearing) from acid/Al stress (since both DSF fry and wild ATS fry will experience acid/Al from fry stage to smolt).
Drawback: will there be enough wild fish for comparison?
Management Activities
a. Change rearing strategies?
b. Change stocking strategies?
c. Determine whether or not to lime the rivers?