Threat sensitivity, fish

My goal in this paper is to briefly describe the role of chemical alarm cues in local risk assessment, focusing on threat-sensitive trade-offs. Specifically, I will address the following questions (1) do prey fish show graded responses in overt antipredator responses with decreasing stimulus concentration, (2) are prey fish able to detect chemical alarm cues below their minimum overt behavioural response threshold, and (3) do prey fish exhibit threat-sensitive changes in behaviour in response to alarm cues at concentrations below the minimum overt response threshold ... 

Fish appear to be particularly sensitive to tetrachlorobenzene and pentachlorobenzene (Table 4.9). Although dinitrotoluene and 2,4,6-trinitrotoluene are also toxic, unsubstituted compounds such as benzene and toluene, as well as ethylbenzene, do not present an immediate threat to fish survival, except at high concentrations. Induction of chronic/sublethal... 

The threat of accidental misuse of quaternary ammonium compounds coupled with potential harmful effects to sensitive species of fish and invertebrates has prompted some concern. Industry has responded with an effort to replace the questionable compounds with those of a more environmentally friendly nature. Newer classes of quaternaries, eg, esters (206) and betaine esters (207), have been developed. These materials are more readily biodegraded. The mechanisms of antimicrobial activity and hydrolysis of these compounds have been studied (207). AppHcations as surface disinfectants, antimicrobials, and in vitro microbiocidals have also been reported. Examples of ester-type quaternaries are shown in Figure 1. 

The spill posed threats to the sensitive food chain that supports Prince William Sound s commercial fishing industry. Also in danger were 10 million migratory shore birds and waterfowl, hundreds of sea otters, and dozens of other species, such as harbor porpoises and sea lions, and several varieties of whales. Adequate resources for cleanup did not reach the accident scene quickly enough. Through direct contact with oil or because of a loss of food resources, many birds and mammals died (EPA, 2003d). 

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