FISHERY BULLETIN: VOL, 77. NO. 3 



Phyllodocid polychaetes secrete copious 

 amounts of mucus when irritated (Fauchald 

 1977). Pettibone (1963) briefly noted that the 

 mucoid secretion oi' Phyllodoce maculata may be 

 offensive to predators. Preliminary observations 

 of P. maculata and P. mucosa (Prezant 1975, un- 

 publ. data) have confirmed that an epitheUal, 

 mucoid secretion acts as an antipredatory 

 mechanism against at least one species offish, the 

 rock gunnel, Pholis gunnel! us. 



The present study extends these observations by 

 quantitative experiments on behavioral interac- 

 tions of Phyllodoce mucosa with several species of 

 small or juvenile fish, and examines the possible 

 defensive mechanism of this polychaete. Initial 

 observations concerning antipredatory 

 mechanisms in the phyllodocids Eumida san- 

 guinea and P. maculata, the large flatworm 

 Stylochus zebra, the sipunculid Phascoleopsis 

 gouldi, and the nemertean Lineus ruber are also 

 reported. 



METHODS 



Phyllodoce mucosa (Phyllodocidae) was col- 

 lected in late August 1978 in Nahant Bay, Mass., 

 by epibenthic sled from a fine sand substratum at a 

 depth of about 17 m. Eumida sanguinea and the 

 orbiniid Scoloplos fragdis were collected intertid- 



ally from Henlopen Flat, Lewes. Del., in early 

 September 1978. Scoloplos fragdis was used as a 

 control in the behavioral experiments because, de- 

 spite its overall gross similarity to phyllodocids 

 (i.e., long, thin worms of similar proportions), S. 

 frogilis produces considerably less external mucus 

 than P. mucosa. Worms were maintained in sepa- 

 rate finger bowls on a running seawater table at 

 17= C and 32%o salinity. 



Fish used in behavioral experiments (Table D 

 were collected in July 1978 and allowed to 

 acclimatize for 30-60 days in separate compart- 

 ments on the seawater table. During acclimatiza- 

 tion, the fish were fed a variety of foods from a 

 widemouthed glass pipette. Foods included bits of 

 fresh blue mussel, Mytilus edulis\ and American 

 oyster, Crassostrea virginica; live tubificid 

 oligochaetes, Tubifex spp.; brine shrimp, Artemia 

 manna; and, infrequently, frozen brine shrimp. 



Phyllodoce mucosa, typically found on fine sand 

 substrata from low water to depths over 500 m, 

 ranges from Labrador to Mexico (Pettibone 1963) 

 thus geographically overlapping with all fish 

 species used in this study (Table 1). 



Since this research dealt principally with the 

 inability of certain predators to eat P. mucosa, it 

 was important to insure that the fish used would 

 actively feed throughout the experimental period. 

 Accordingly, several other species of polychaetes 



Table l. — The range, habitat, food habits, and collection sites of the species offish used in the feeding experiments. The last column 

 lists the test organisms offered to fish. Quantitative results are available only (or Phyllodoce mucosa . Range, habitat, and feeding habit 

 data for the fish are from Hildebrand and Schroeder ( 1928), Bigelow and Schroeder (1953), Chao and Musick (1977). and Kneib and 

 Stiven(1978). 



Fish species 



Range and habitat 



Feeding habits 



Fish collection site 



Test organism 



Atlantic silverside. 

 Menidia menidia 



Weakfish, 

 Cynoscion regahs 



Windowpane flounder, 

 Lophopsetta maculata 



Sheep shead minnow. 

 Cypnnodon variegatus 



Mummichog, 

 Fundulus heteroclitus 



Threespine stickleback. 

 Gasterosteus aculeatus 

 Striped sea robin. 

 Pnonotus evolans 



Rock gunnel. 

 Pholis gunneius 



Nova Scotia to northern 

 Flonda. often over 

 sandy or gravelly shores 



Nova Scotia to Florida, 

 shallow coastal waters 

 in summer 



Gulf of St Lawrence to 

 South Carolina, sand bot- 

 toms from low water to 50 m 

 Cape Cod to Mexico, 

 shallow waters ot inlets 

 and bays, salt marshes 

 Labrador to Mexico, 

 shallow coastal waters 

 especially salt marshes 



Labrador to Virginia; 

 salt and fresh waters 

 Gulf ol Maine to South 

 Carolina, coastal bottom 

 dweller 



Hudson Strait to Delaware, 

 generally on rocky bot- 

 toms from low Water to 

 over 200 m 



Small crustaceans and 

 molluscs, annelids, 

 small fish, eggs, and 

 plant malenal 

 Fish, crabs, amphipods, 

 mysids, shnmp, mol- 

 luscs, annelids 

 Mobile prey such as 

 mysids. fish, shrimp, 

 errant polychaetes 

 Mobile epifauna 

 including annelids 



Omnivorous (at least 

 when -30 mm) including 

 small crustaceans, 

 annelids, and carnon 

 Small invertebrates, 

 fish fry, eggs 

 Crustaceans, molluscs, 

 annelids, small fish 



Molluscs, crustaceans, 

 annelids 



Lewes Beach. Lewes. 

 Del 



Lewes Beach 



Lewes Beach and 

 near Delaware Bay 

 mouth at 1 8 m 

 Lewes Beach 



Canary Creek. 

 Lewes. Del 



East Point. Nahant, 

 Mass , tide pool 

 Near Delaware Bay 

 mouth at 18 m 



East Point. Nahant 

 tide pool 



Phyllodoce mucosa 

 Scoloplos fragilis 



P mucosa 



Phascoleopsis gouldi 

 S fragilis 



Phyllodoce mucosa 

 Eumida sanguinea 

 S fragilis 

 P mucosa 

 S fragilis 



P mucosa 



Phascoleopsis gouldi 

 S fragilis 



Phyllodoce mucosa 

 S fragilis 

 Stylochus zebra 

 Phascoleopsis gouldi 

 Uneus ruber 

 Phyllodoce mucosa 

 P maculata 

 Nephtys incisa 



606 



