MEYER ET AL AMERICAN SAND LANCE FROM THE GULF OF MAINE 



declined drastically, to <1 sand lance/tow, when 

 not fishing on the bank. In the southwest North 

 Sea, fishermen have also noticed that better 

 catches occur along the edges of larger banks and 

 on the tops of smaller ones (Popp Madsen 1963). 



In the last 10 yr, sand lance have shown evi- 

 dence of a population increase along the Atlantic 

 coast from Cape Hatteras, N.C.. to and including 

 the Gulf of Maine. Northeast Fisheries Center 

 spring and fall bottom trawl survey results from 

 1968 to 1977 show large annual fluctuations in 

 sand lance abundance since 1968 with a definite 

 upward trend beginning in 1975 (Figure 4). The 

 magnitude of this increase is considerably less 

 than that recorded on Stellwagen Bank for the 

 same period, but the yearly trends are similar. 



One area of concern in attempting quantitative 

 sampling is net avoidance. Livingstone (1962) 

 documented on film that adult sand lance were 

 able to escape in <2.5 s from the cod end of a 

 Yankee Modified #41 trawl net with a cod end 

 mesh of 1 14 mm, knot to knot, and a -SS-mm cotton 

 webbing covering. These films also showed the 

 ease with which individuals and small schools 

 were able to avoid the trawl net. In areas where 

 abundance is high, the ability to avoid trawl nets 

 maybe less effective. Scott ( 1973) found it unusual 

 to catch adult sand lance in nets except in areas 

 where they were very abundant. 



Relative abundance of sand lance on Stellwagen 

 Bank and Provincetown slope, based on diver and 

 submersible observations, has increased sig- 

 nificantly since 1976 (Table 1). Although numer- 



- SPRING BOTTOM TRflWL SURVEr 



- fALL eoT TOM TRflWL SUftVE » 



Figure 4. — Changes in the relative abundance of adult Ammo- 

 dytes spp. in the Northeast Fisheries Center spring and fall 

 bottom trawl surveys from 1968 to 1977 in the area extending 

 from Cape Hatteras northward. (Data from Grosslein et al. in 

 press, table 3.2.) 



ous diving programs have been carried out over 

 the study area since 1968, it was not until the 

 spring of 1976 that .schools of sand lance were first 

 observed. However, it is very likely that relatively 

 small numbers of sand lance were present in the 

 study area prior to 1976 but not noticed by the 

 divers. This increase in sightings coincides with 

 an increase in number of sand lance caught per 

 tow during the bottom trawl survey cruises. 



Sand lance larvae studies, conducted by the Bos- 

 ton Edison Company^ showed sand lance larvae 

 were among the most abundant fish larvae occur- 

 ring in ichthyoplankton sampling surveys con- 

 ducted in Cape Cod Bay, Mass., d.'ring 1974-77. 

 They were more abundant in the eastern portion of 

 the bay and were considerably more abundant in 

 1976 than in the previous 2 yr. This mcrease in 

 sand lance larvae was also observed during the 

 Northeast Fisheries Center spring ichthyo- 

 plankton surveys conducted in the area from Cape 

 Hatteras to the Gulf of Maine for the past 4 yr 

 (Figure 5). For example, the mean sand lance 

 catch/10 m^ area in spring 1977 was 9 times great- 

 er than in spring 1974. 



Bottom trawl survey results, diver and submer- 

 sible observations, and ichthyoplankton survey 

 results all indicate that there is a relatively large 

 concentration of sand lance inhabiting a small 

 section of the Gulf of Maine, i.e., Stellwagen Bank 

 and outer Cape Cod (Provincetown slope), and that 

 this population has increased considerably since 

 197.5; this increase in population is typical of the 

 Northwest Atlantic from Cape Hatteras to the 

 Gulf of Maine. 



Behavior 



School Structure 



Schools of sand lance observed on the Province- 

 town slope were relatively small in numbers of 

 fish, ranging from about 100 to several thousand 

 individuals and were usually found in depths 

 ranging from 6 to 20 m. From photographs it was 

 calculated that individual fish on Provincetown 

 slope ranged from approximately 12 to 17 cm long, 

 with a mean of 15 cm. Sand lance schools observed 

 on Stellwagen Bank were relatively large in num- 

 bers, ranging from about .500 to tens of thousands 



'Boston Edison Company. 1974-77. 

 related to operation of Pilgrim Station. 

 Boylston Street, Boston. MA 02199. 



Marine ecology studies 

 Boston Edison Co., 800 



247 



