Daily Archives: March 31, 2009

Habitat use

Gregg Schorr for Brad, dive behavior

  • Is dive depth related to prey preference?
  • Do dive rates vary between pods, day/night, years?
  • Is frequency of max dive depth constant over time?

Prey field mapping in Sept, 2004 (after sockeye, during fall Chinook run): big targets are near middle of water column (>100m); prey assemblages different in Haro Strait?

Wild Salmon Center identified rivers with multiple runs and little development that could be wild salmon “strongholds” or refuges during an age of global warming.

40 deployments 93-2000, 419 hours data, median duration of deployment 10.5hrs.  Velocity spikes are often associated with deepest portion of dive (and some shallow dives).

What are accelerations in shallow dives?  (Tried critter cam)

All individuals old/young and across pods have similar dive profiles and all swam slower at night, but males dive deeper than female adults (but only during day).  There is also an inexplicable change in depth of dives over the years.

Focal follows show they don’t go to the bottom (e.g. 150m dive in 300m water).  This summer we’ll use new tags with a hydrophone and body orientation sensors.  Also planned are satellite tagging efforts.

Rich Osborne, long-term patterns in SRKW residency

43,000 sightings in the OrcaMaster database 1980-2008 (biased towards summer initially, but in last 2 decades it’s become more balanced).  Puget Sound is Admiralty Inlet and Deception Pass south.

After L pod members spent ~a month in Dyes Inlet, they extended their stay in inland waters ever since.  They didn’t often do that before.  This suggests they can adapt to different prey (e.g. Chilco Creek Chum) when stressed (there was only chum to eat in Dye’s Inlet).

NW Straits and Puget Sound seem to be getting more attention in last decade compared with previous 2 decades.  We should be spending all PS salmon restoration  money for those wild rivers.

SRKW health

Pete for Steve Rafferty, epidemiological and pathologic findings

Only 10/81 confirmed SR deaths and 4/142 of NR were beach cast and available for post-mortem examination.  Infectious pneumonia is most common reported cause of mortality (60% of those necropsied).  We now have a standardized protocol for doing necropsies (available at http://seadocsociety.org)  Since 2002, Steve and Joe Gaydos have been trying to determine if bacterial infection was the primary cause of death.

Pete Schroeder, microbial assessment of orca breath and marine microlayer

Used 4 petri dishes swept through blow of adult males.  Each dish has a different medium.  Sampled in 06-08, mostly in late summer/fall.

Partial results:

  • L74: Salmonella heidelberg (resistant to 2 antibiotics)
  • J1: Vibrio alginolyticus (resistant to 1 antibiotic)
  • L41: Pseudomonas fluorescens (resistant to 4 antibiotics)
  • >50 bacteria and fungi in local microlayer, similar to biodiversity in Hawaiian waters

Q: Has there been any attempt to correlate the bacteria in the microlayer you sample with local sources of contamination?  Sewer water is a likely source of antibiotics and endocrine disruptors.

Kathrine Ayres, physiological monitoring of SRKW

Looked at two compounds and two sources of change:

  • Glucocorticoids (GC, stress hormone) and thyroid (T3, nutrition)
  • Nutritional deficit (lowers GC, raises T3), stress from boat interactions (raises GC, doesn’t affect T3)

Prey levels (DFO test catch fishery, Chinook CPUE) and boat density time series increase in May, peak mid-summer, and tail off in the fall.  Samples taken with pool net or 2-liter bottle examined per gram of dry weight.

Results:

  • GC falling from May, lowest in July/August, rising towards winter (supports Prey+Boats hypothesis — whales experience times of nutritional stress and disturbance by boats.
  • T3 levels in 2008 significantly lower than in 2007 (bad salmon year in 2008)

John Durban, Size and body condition of SRKWs

Southern residents are food limited and culturally specialized to Chinook prey.  Used laser pointers for morphometrics (of commonly visible body parts).  Pitmann, 2007 used size of type C killer whales in Antarctica.  10 filights in September 2008 (elevation >750′ according to permit), 12,000 photos, differential GPS gave accuracy of 2-3m (altitude).  Measured length, girth, and head width, calibrated with boat photos.

We were able to estimate boat lengths well.  We can see growth curves and hope to be able to resolve changes in growth rate.  We can use the head width to estimate body condition.  Dependent young tend to have fattest head, and their mothers are often the thinnest.

Contaminants in SRKWs

Sandra O’Neill, Contaminants in salmon

We’ve heard that S and N residents are both eating mostly Chinook.  Why are the southern residents more contaminated than the northern residents?

Contaminants in fish are determined by:

  • where they live
  • what they eat
  • how long they are exposed
  • how fat they are

Chinook and Coho have elevated [PBDE] because they stay close to shore, while other salmon have undetectable levels.  For PCBs are more widely dispersed and present in all salmon, but are highest in Chinook.  Puget Sound fish are always much more contaminated than northern fish.

Along the west coast, [PCB] peaks at Puget Sound and are about the same at Skeena (north extreme) and Sacramento (south exptreme).  Within Puget Sound, the resident Chinook (blackmouth) are ~3x as contaminated as non-resident Chinook.

Prey quality is also decreasing along W coast.  Size is decreasing and kcal/fish is variable.  PS fish are smaller and have lower lipid concentration.  This means Puget Sound non/resident Chinook will give you ~7/16X PCBs compared to Skeena Chinook!

Peggy Krahn, persistent organic pollutants (POPs) threats to SRKWs

Fisheries and Oceans Canada collected 3 biopsy samples in 2004; NWFSC collected 18 samples in 2006-7.

Most SRKWs have [PCB] exceeding threshold for health effects.  Juveniles have much higher concentrations of many POPs (PBDEs, HCGs, and HCB) than adults in their pods.   This happened mostly by transfer from their mothers during lactation.  The levels are above the estimated threshhold for health effects.

The prevalence of DDT use in CA raises the ratio of DDTs/PCBs above 1.  K and L pods have this California signature while J pod doesn’t, which is nicely explained by the observation that J pod haven’t been observed south of Newport, OR.

Teresa Mongillo, predicted contaminant levels in SRKWs

Developed an IB Model which assumes that the Amount of prey consumed = PCB, PBDE in prey + milk – gestation -lactation

Currently there is no change in the [PCB] while [PBDE] is increasing exponentially.  Projections were made for different scenarios (variable rates of increase).   The model predicts that PCBs will begin to decline after 20+ years; PBDE levels will exceed current PCB levels in 2-40 years.

PCBs increase with age in males, but decreases with offspring in females.  In contrast, PBDEs don’t seem to increase but they cluster into groups that are living vs dead… this suggests a potential dose-related effect on calf survival. PCBs decrease with birth order (the first-born gets the biggest load).

Questions:

Rich Osborne: Are heavy metals in such low concentration that they are not of concern?  Peggy: Epidermis samples are reserved for stable isotopes and genetics, so there is a sample size limitation.  Sandra: Hg levels are slightly higher in Chinook and Coho.

Jeff Lorton:  Should we tell our passengers not to eat Chinook?  Should we catch/release Chinook across whole region?

Ken Balcomb: Has anyone initiated a study of POPs in local humans, e.g. sports and commercial fishers?  There is good analogous study from the Great Lakes.

Prey relationship talks

8:35 John Ford, resident KW foraging ecology

What may have caused the simultaneous declines in the N and S residents during the late 1990s?  Nutritional stress?

We compared expected and observed births and deaths, where expectations were based on period of unlimited growth (’73-’90).  There were two phases of increased mortality in adult/juvenile fe/males: late 90s for N and S, mid-80s for southern and A pods.

Sockeye outnumber Chinook by 1000x in areas where residents forage during the summer.  Yet Sockeye make up less than 1% of diet during sampling period (May-Oct).  Only adult males don’t bring prey (of all species) to the surface for sharing.  This indicates that our surface prey fragment sampling technique isn’t biased.  Additionally, sockeye swim shallow and Chinook deep, but we’ve only sampled 3 sockeye predation events.

Sub-adults show some preference for smaller fish like Pink and Chum that make up about about 20% of their diet.  Recent winter sampling show continued chinook preference: 2 samples in Jan from N residents; 2 from J pod near Nanaimo Chinook.  They didn’t see enhanced mortality in weaners (expected in mammals under nutritional stress), perhaps because of prey sharing. Mortality lags chinook abundance by 1 year.

The Chinook abundance index is a bit below average currently, so we expect high mortalities next year.  A research priority is to identify important Chinook stocks for whales (Brian Gisborn, Brad Hanson).  How many are hatchery fish?

9:01 Jennifer (for Brad), species and stock ID for southern residents

Goals were to supplement Ford’s prey samples (beyond J pod), to collect fecal/regurgitation samples (to avoid potential bias in surface fragment sampling), and to define foraging surface behavior.  We now have ~150 fecal samples and 250 foraging samples that have been analyzed genetically.

Feces were screened for rockfish, sole, starry flounder, pacific halibut,  Irish lords, herring, sculpin, sable fish, greenling, lingcod, cabezon, and squid.  Thus far, we have detected (rarely) rockfish, sole, Pacific halibut, and lingcod.

Prey sampling results — Steelhead may be imporant in May.  Chinook dominate from May-September.

Fecal sampling results — Chinook dominate in May-September, but Chum is also important in September.

Breakdown of Chinook stocks is based on GAPS database which gives genetic profile for each river from 20k sampled fish.  They appear to be eating Chinook in rough proportion to what is available (most dense by number? biomass?).

Future work is focused on bioenergetics (how many fish do they consume and do they impact the stocks?) and availability (Is background noise impeding foraging efficiency?).  We need samples in Sept-Dec and May!

Eric Ward, risk analysis

Developed a fecundity model which was age specific (the rate of maturity is much faster than rate reproductive senesence).  Extrinsic factors were prey, contaminants, anthropogenic events (oil spills).  Can’t assess oil spill risks and disease risks (due to lack of data), nor do extant data help us characterize the variability of fecundity between sub-populations (e.g. pods) and indivduals.

Used Pacific Fisheries Management Council (PFMC) indices (terminal run) from to characterize prey.  Also look at Pacific Salmon Commission (PSC) relative index.  Ballard locks was used to get a U.S. sockeye time series to compare with the big (25 million) Fraser sockeye runs.  Used ENSO and PDO time series to characterize climatic variability.

Is the SR production different from NR?  It looks similar (~90+% of NR production rate).  High probability of prey (Chinook) correlates highly w/fecundity.  Late run Fraser and Oregon coastal stocks are driving the correlation of the prey variable.