Stress in Pacific Coast Fish

Stress in Pacific Coast Fish



  • Large human population in southern California impacts local
    marine environment every day!
  • Many local fish species studied for affects on stress axis via
    exposure to human derived chemicals
  • Fish in affected sites have a 50% reduction in stress response
    compared to fish from far-field locations
  • An impacted stress axis can lead to a fish being more prone to
    infections, parasite infestation and other physiological affects


Stress in Pacific Coast Study

Southern California is home to a large human population that every single
day impacts the local marine environment.  With a population around 10
million people residing in Los Angeles County and another 2.5 million in
Orange County, the daily activities of all these people affects the health of
the marine environment and the organisms living in it.  We have been
working closely with Orange County Sanitation District (OCSD), City of Los
Angeles Environmental Monitoring Division (CLAEMD), California State
University-Long Beach, and University of California-Riverside, to study how
looking at a fish and its endocrine response can tell us how the environment
is impacting the organism.  This is a very important and powerful tool to use
in environmental assessment/research, to allow the organism to tell you
what is wrong with it by looking at physiological functions of the fish.
We have sampled fish from Santa Monica Bay stretching down to Dana Point;
as well as some in the San Francisco Bay [see S.F. Bay study page].  In
these stress studies we looked  Pacific sanddab (Citharichthys sordidus),
Hornyhead turbot (Pleuronichthys verticalis), English sole (Parophrys
vetulus) and California scorpionfish (Scorpaena guttata.)  These fish are
common to our local waters and tend to be exposed to a variety of
human-derived chemicals, both natural and synthetic.  Our study has shown
that those fish found at outfall sites, where there is a higher incidence of
exposure occurs, have significant affects to their stress axis compared to
fish from far-field stations.  In some cases, like in English sole, there was a
50% reduction in function of the stress response for fish from outfall sites
compared to far-field sites.  A compromised stress axis will not allow a fish
to normally deal with stressful events and can leave it prone to infection,
infestation of parasites and in a vulnerable state when faced with predators.
Continuing studies are underway to better understand the affects of such
physiological disruption.


^ English sole collected off the Palos Verdes shelf
in Newport Beach



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