Vol. 53 - Alaska Resources Library and Information Services

and Alaskan species of shrimp and crab including Dungeness crab, king
and Tanner crab, and pandalid shrimp. Rice, et al. (1976) and Vanderhorst,
et al.
(1976) reported that 96 hr LC[subscript]
50 values for juvenile and
adult pandalid shrimp range from 0.8-11.0 mg 1[superscript]-1
WSF. Pandalid larvae,
however, are a more sensitive life history stage as evidenced by 96 hr
LC 50 values from 1.0 mg 1[superscript]-1
WSF down to 0.3 mg 1[superscript]-1
for single aromatic
compounds such as naphthalene (Mecklenburg, et al.
1977; Rice, et al.
1976, 1979). Sublethal effects including failure to swim and/or molt
inhibition occurred at concentrations from 0.7 to 0.3 mg 1[superscript]-1
WSF. A 96
hr exposure of pandalid larvae to 0.6 mg 1[superscript]-1
WSF caused a 70 percent
reduction in molting from SI to SII (Mecklenburg, et al. 1977).
Dungeness
crab zoeae were susceptible to WSF as low as 0.22 mg 1[superscript]-1
(Caldwell,
et al. 1977).
hydrocarbons.
Larval king and Tanner crab are equally sensitive to
Death of Paralithodes camtschatica larvae or failure to
swim was caused by WSF of 0.8 to 2.0 mg 1[superscript]-1
(Brodersen, et al. 1977;
Mecklenburg, et al. 1977), and Chionoecetes bairdi larvae were immobilized
by a 96 hr exposure to 1.7 mg 1[superscript]-1
WSF (Brodersen, et al. 1977).
Studies with other larval decapods indicate that toxic oil concentrations
may be even lower than those discussed above when based on assays
of single hydrocarbons, exposures longer than 96 hr, or based on sensitive
sublethal criteria.
Larval lobster (Homarus americanus) ceased
feeding at 0.19 mg 1[superscript]-
1
WSF and had a 30-day LC 5 0 value of 0.14 mg
(Wells and Sprague 1976).
Specific compounds such as naphthalene are
very toxic and caused narcotization followed by death of pandalid shrimp
and crab larvae at concentrations of 8-12 ug 1[superscript]-1
during exposures
of less than 24 hr (Sanborn and Malins 1977).
Toxic oil concentrations
range as low as 0.15 mg 1[superscript]-1
WSF and may be somewhat lower for specific
compounds. Moore and Dwyer (1974) give a sublethal range of 0.0011-0.1
mg 1-1 WSF as stressful to larvae.
Wells and Sprague (1976) suggest
a multiplier of 0.03 should be applied to LC 5 0 concentrations to establish
"safe" levels; this would result in acceptable concentrations less
than 1 ug l[superscript]-
1 . Armstrong, et al. (1983b) suggest that the toxic
threshold value of 0.2 mg 1[superscript]-1
WSF used in oil spill scenarios be lowered
to 0.05 to 0.1 mg 1[superscript]-
1
in light of this evidence.
1[ s u pe r s cr i p t]
-1
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