FISHERY BULLETIN: VOL, 77, NO, 1 



a Yankee #36 trawl (Grosslein^). The cod end and 

 upper belly of the net were lined with 13-mm mesh 

 netting, knot to knot. Only three species of fish 

 were caught in any quantity: spiny dogfish, 

 Squalus acanthias; silver hake, Merluccius 

 bilinearis; and American sand lance. Sand lance 

 were taken at random from the catch and pre- 

 served whole in lO'^f Formalin for stomach- 

 content analysis. 



In the laboratory, the stomachs were dissected 

 out for stomach-content analysis. Ten fish from 

 each of the nine tows were randomly selected from 

 the preserved specimens for analysis. After the 

 stomach was removed from each fish, the contents 

 were examined and washed onto a fine-mesh 

 screen. If the stomach appeared empty or had trace 

 amounts (<1.0 mg) of food in it, it was rinsed out 

 with seawater directly into a Petri dish. When 

 there was a weighable quantity of prey present, 

 the excess water was drawn off by pressing an 

 absorbent tissue paper to the underside of the 

 screen; the contents were weighed and then 

 washed into a Petri dish. Using a dissecting micro- 

 scope, the prey of each fish were identified to the 

 lowest possible taxonomic grouping, and the per- 

 centage composition of each of the identified 

 groups estimated. The percentage composition 

 and total stomach-content weight were used to 

 calculate the percentage weight for each prey 

 category. The data were also expressed in terms of 

 the percentage occurrence of each prey group in 

 the stomachs. 



from 30 to 31 with a mean of 30.7, SD = 0.48. The 

 dorsal fin ray count ranged from 60 to 63 with a 

 mean of 61.1, SD = 0.99. The vertebral count, 

 based on radiographs of 20 fish and excluding the 

 hypural complex, ranged from 67 to 72 and aver- 

 aged 69.25, SD = 1.21. The mean values reported 

 here fell into the A. americanus category given by 

 Reay (1970). For the purpose of this paper, the 

 classification of Reay (1970) is accepted. 



Relative Abundance 



Examination of spring and fall survey data for 

 the past 10 yr, excluding 1967, 1969, 1971, and 

 1973 for spring and 1971 and 1977 for fall (Stell- 

 wagen Bank stations were not sampled), indicates 

 a substantial increase in sand lance abundance on 

 Stellwagen Bank (Figure 3). The relative abun- 

 dance increased during spring cruises from virtu- 

 ally for the 1967-75 period to 50/tow in 1976 and 

 10,729/tow in 1977, while increasing during fall 

 cruises from for the 1967-74 period to 4,238/tow 

 in 1975 with a decrease to 5/tow in 1976. Spring 

 cruises (March- May) may give a better indication 

 of sand lance abundance since fall cruises are con- 

 ducted from October to December, a period of les- 

 ser sand lance activity before spawning ( Winslade 

 1974). In the Gulf of Maine, all bottom trawl sur- 

 vey catches <75 sand lance/tow occurred on or 

 along the edge of Stellwagen Bank. The catch rate 



RESULTS AND DISCUSSION 



In the taxonomic studies listed above, mor- 

 phometric and meristic characteristics were used 

 to distinguish between "inshore sand lance" 

 [Ammodytesai7iericaniis -Ainmodytes hexapterus ) 

 and "offshore sand lance" (Ammodytes dubius), 

 although Bigelow and Schroeder (1953) ques- 

 tioned whether such a distinction could be made. 



Because of the question regarding the 

 taxonomic status of A. americanus and A. dubius. 

 several meristic characteristics were evaluated on 

 sand lance caught on Stellwagen Bank (Figure 

 2D). Dorsal and anal fin ray counts were made 

 directly on 10 randomly chosen fish ranging from 

 17.9 to 22.2 cm fork length (FL) and averaging 

 20.0 cm, SD = 1.24. The anal fin ray count ranged 



10.000 



9000 



J 6000 



 4000 



SOOO 



900 



' 700 



, 500 



: soo 



SPRING BOTTOM TRAWL SUBVET 



FALL BOTTOM TRAWL SURVEY 



-A/- NOSAMPLE COLLECTED 



oyv= 



1967 





■=!^ V=^ 



^Grosslein, M. D. 1969. Groundfi.sh survey methods, 

 >fMFS, Woods Hole, Massachusetts. Lab. Ref. No. 69-02, 34 p, 



246 



Figure 3. — Catch of adult sand lance per standard tow on Stell- 

 wagen Bank during the NMFS .spring and fall bottom trawl 

 stratified sampling surveys for 1967-77. 



