,,-- 





6 0/ 



\ • , -V 



\ 40°30 







10 





/ 



//TOO/ 1 



1 !*-~* 

 7"fr-t. ) 



/ / 



{< I 8 o ; 



And \ \\ so l 



4020' 



[~J 1-9? m? 

 y 100-139/ 



4010- 



73°50' 

 i ■ 



73°40' 



Figure 29. — Distribution and abundance of Glycera dibranchiata in the New 

 York Bight apex. 



lipolytic enzymes (Vahl 1976). On the basis of morphology, it may 

 be postulated that glycerids are primarily carnivorous, but are capa- 

 ble of using other feeding modes under certain environmental con- 

 ditions. 



Spawning bloodworms are preyed on by herring gulls. Larus 

 argentatus, and striped bass, Morone saxatilis, while spent epi- 

 tokes are consumed by shrimp (Crangon septemspinosa) which, in 

 turn, are eaten by striped bass (Creaser 1973). Glycera dibranchi- 

 ata has also been found in the stomachs of haddock off Georges 

 Bank (Wigley 1956). 



most rapid during the second and third years, decreasing sharply 

 thereafter. 



In contrast, the study by Simpson (1962) showed G. dibranchi- 

 ata to breed twice a year in Solomons, Md.. during fall and during 

 late spring or early summer as well. She observed swarming taking 

 place over a moderately large area in shallow water during late 

 afternoon on 5-8 November 1960. Her data suggested that the 

 onset of swarming may be coordinated with tidal conditions. The 

 pelagic larvae that were produced were nearly or fully indifferent to 

 light in their early phases. Her other findings were in general agree- 

 ment with those of Klawe and Dickie (1957). 



Creaser (1973) studied a population of G. dibranchiata in Wis- 

 casset, Maine. He found them to spawn annually in June, usually at 

 an age of 3 or4yr. A bottom temperature in excess of 13°C seemed 

 necessary for spawning to occur. Generally, between 2 h before and 

 1 h after high water in the afternoon, males emitted streams of 

 sperm while swimming at the surface, while females swam rapidly 

 at the surface and suddenly ruptured, liberating all eggs at once. 

 Eggs usually measured 1 5 1 - 1 60 /*m in diameter. Klawe and Dickie 

 (1957) have calculated that a bloodworm measuring 22-24 cm may 

 contain 1.5-2.0 million eggs. A Wiscasset bloodworm of this 

 length would be expected to contain 3.0-3.5 million eggs. The 

 emission of gametes in the Maine study was not, however, confined 

 to surface waters. Creaser (1973) also observed a male in 3 m of 

 water swimming in a vertical position just above the bottom emit- 

 ting sperm. 



All observations agree with the belief of Klawe and Dickie 

 (1957) that all bloodworms die after spawning, with 5 yrthe maxi- 

 mum life span. The size range of sexually mature bloodworms in 

 Maine was between 18 and 51 cm (Creaser 1973); in Nova Scotia. 

 13-36 cm (Klawe and Dickie 1957); in Maryland, 7-26 cm (Simp- 

 son 1962). These geographical differences in size of bloodworms 

 may be attributed to the effects of temperature on growth and matu- 

 rity or possibly to differences in races of bloodworms. An interest- 

 ing observation made by Klawe and Dickie (1957) was that G. 

 dibranchiata does not grow in summer months. This finding is in 

 direct contradiction to almost every other temperate or boreal inver- 

 tebrate studied. 



ADDITIONAL INFORMATION: G. dibranchiata is harvested 

 extensively from the mud flats of Maine and other Gulf of Maine 

 areas. There, it supports a multimillion dollar bait worm industry. 

 In the New York Bight, it is not commercially harvested, but is col- 

 lected by recreational fishermen. 



REPRODUCTION AND GROWTH: The reproductive patterns 

 of G. dibranchiata have been studied by several investigators. 

 Klawe and Dickie (1957) made observations on a population of G. 

 dibranchiata from Goose Bay at Wedgeport, Nova Scotia. They 

 found that eggs and sperm began developing in late summer and 

 were sexually mature by early April (fully developed eggs mea- 

 sured between 1 80 and 1 90 /tm in diameter) . The peak of spawning 

 took place in mid-May; after spawning, remains of spent worms 

 were found on the flats, appearing as "ghost worms," consisting of 

 outer skin and atrophied digestive tract with everted proboscis. 

 This indicated that life terminates after spawning (the spawning 

 process itself was not observed). Eggs developed into planktonic 

 larvae which, after a short time, transformed into bottom dwellers. 



From an analysis of distribution of size classes in the population, 

 Klawe and Dickie (1957) determined that most of the intertidal 

 population lives for 3 yr and that they spawn before reaching the 

 fourth year; a small fraction spawn when 4 or 5 yr old. Growth is 



Goniadella gracilis (Verrill, 1873) 



DESCRIPTION: Active worms making temporary burrows in 

 sand (Dales 1963). Length to 50 mm. width to 1 mm. segments to 

 100 or more (Pettibone 1963). 



DISTRIBUTION: Massachusetts to Virginia: Irish Sea. Liver- 

 pool Bay, South Africa (Walker 1972; Day 1973). 



HABITAT: Intertidal to 450 m (Day 1973). Found burrowing in 

 fine sand at low water; collected on bottoms of fine gravel, fine to 

 coarse sand and soft mud (Pettibone 1963; Walker 1972). 

 Goniadella gracilis was one of the dominant species on the mid- 

 continental shelf in the Delaware Bay region, associated with 

 poorly sorted, coarse sediments ( > 1 mm) (Kinner and Maurer 

 1978), and was among the 15 most abundant taxa on Georges Bank 

 in winter (Maurer and Leathern 1980). It was also abundant in some 



21 



