IMPAIRMENT OF THE CHEMOSENSORY ANTENNULAR FLICKING 



RESPONSE IN THE DUNGENESS CRAB, CANCER MAGISTER, 



BY PETROLEUM HYDROCARBONS 



Walter H. Pearson,' Peter C. Sugarman/ Dana L. Woodruff,' and Bori L. Olla^ 



ABSTRACT 



After exposing Dungeness crabs in a continuous-flow system to seawater contaminated with Prudhoe 

 Bay crude oil (0.27 parts per million), we observed the behavior of crabs presented with a clam extract. 

 In response to seawater solutions of clam extract, Dungeness crabs change antennular orientation and 

 increase antennular flicking rate. After 24-hour exposure and with oil still present, the proportion of 

 crabs showing the changes in antennular behavior indicating detection of chemical food cues was 

 significantly reduced. In contrast, the proportion showing chelae probing was not. Within 1 hour after 

 return to clean water the antennular response recovered. Such rapid recovery indicates that the 

 chemosensory impairment probably did not derive from structural damage to sensory cells but does not 

 indicate which of several other possibilities was the most likely mechanism. By impairing the 

 chemosensory antennular flicking response of Dungeness crabs, petroleum hydrocarbons could cause 

 crabs some difficulty in finding food. 



For marine organisms, disruption of chemorecep- 

 tion by oil is viewed as both likely and of impor- 

 tant ecological consequence (Blumer 1969; 011a et 

 al. 1980). Chemosensory disruption by various 

 petroleum hydrocarbons and oil fractions has been 

 reported in snails (Jacobson and Boylan 1973; 

 Hyland and Miller 1979), lobsters (Atema and 

 Stein 1974), and in shore crabs (Takahashi and 

 Kittredge 1973). In some of these early studies the 

 exposure regime was not well defined and did not 

 always compare well with the length and level of 

 exposure likely to be encountered in oil spills. 

 Here we report on the ability of the Dungeness 

 crab. Cancer magister Dana, to detect and respond 

 to a food extract after 24-h exposure to seawater 

 contaminated with Prudhoe Bay crude oil in a 

 continuously flowing seawater system. 



The antennules of many decapod crustaceans 

 are a site for chemoreception of water-borne chem- 

 ical cues (Hazlett 1971a). Antennular flicking may 

 be analogous to sniffing in vertebrates (Fuzessery 

 1978) and enhances the ability of crustaceans to 

 detect changes in their chemical environment 

 (Schmitt and Ache 1979). Behavioral observations 

 of antennular flicking rate indicate that detection 

 of a clam extract occurs at 10"'^ g/1 in the blue 



'Battelle Pacific Northwest Laboratories, Marine Research 

 Laboratory, Washington Harbor Road, Sequim, WA 98382. 



^Northeast Fisheries Center Sandy Hook Laboratory, Na- 

 tional Marine Fisheries Service, NOAA, Highlands, NJ 07732. 



Manuscript accepted June 1981. 



FISHERY BULLETIN: VOL. 79. NO. 4, 1981. 



crab, Callinectes sapidus (Pearson and 011a 1977), 

 and at 10 "^'^ g/1 in the Dungeness crab (Pearson 

 et al. 1979). 



To determine whether exposure to petroleum 

 hydrocarbons impaired this acute detection abil- 

 ity, we exposed Dungeness crabs to oil-contam- 

 inated seawater for 24 h, presented them with a 

 clam extract in the presence of the oil-contam- 

 inated seawater, and recorded the percentages of 

 crabs showing the changes in antennular behav- 

 ior indicative of detection and of those showing the 

 chelae probing indicative of food searching. At 24 

 h and 48 h after stopping the flow of oil-contam- 

 inated seawater, we retested the crabs to deter- 

 mine the time necessary for recovery of detection 

 ability. Because this first experiment indicated 

 rapid recovery, we performed a similar second 

 experiment in which we presented the clam 

 extract to Dungeness crabs 1 h after stopping the 

 flow of contaminated seawater. 



MATERIALS AND METHODS 



Animal Collection and Maintenance 



Dungeness crabs trapped in the Strait of Juan 

 de Fuca, Wash., were held under the conditions 

 described by Pearson et al. (1979). Seawater tem- 

 peratures during the two experiments were 8.9 

 (±2.7 SD)° C (n = 16) and 9.2 (±0.5)° C in = 



641- 



