collections. This indicated that their spawning and 

 early life history strategies reduced their suscepti- 

 bility of being entrained. 



American sand lance 



ITie American sand lance is found from the 

 Arctic to Cape Hatteras (Bigelow and Schroder 

 1953). They are primarily pelagic plankton feeders 

 (Richards 1982). Individuals form large schools 

 and are found over sandy bottoms from near 

 shore to the edge of the continental shelf (Richards 

 1963; I^im and Scott 1966). Sand lance mature 

 in 1 to 2 years and spawn between December and 

 March (Westin et al. 1979). The life span of the 

 sand lance has been reported as 5 to 9 years 

 (Westin etal. 1979; Grosslein and Azarovitz 1982). 



The sand lance was collected in all fish ecology 

 programs, but primarily during its larval stage in 

 the winter and spring. It has generally contributed 

 less than 1 % to armual total impingement (Table 

 4), except for the previously discussed one large 

 impingement occurrence in 1984. Few were col- 

 lected in the trawl and seine samples, possibly 

 because juveniles and adults burrow into the sand 

 (Leim and Scott 1966), thus avoiding these gears. 

 Eggs were rarely collected because they are 

 demersal and adhesive (Frizsche 1978). The sand 

 lance was the third most abundant larval species 

 at EN and NB. Aimual entrainment estimates, 

 based on median densities, ranged from 2.8 to 

 66.7 million (Table 7). 



TABLE7. Annual entrainment estimates and 95% conndence 

 intervals for American sand lance larvae entrained at MNPS. 



Annual larval abundance and temporal occur- 

 rences were compared based on parameters from 

 the Gompertz function. The function fitted the 

 data well; all R^ values exceeded 0.94. Generally, 

 larvae were collected from December through 

 May, but the estimated dates of peak abundance 

 (as determined by the inflection point) were quite 

 variable both from year to year and between EN 

 and NB within a year (Table 8). The a parameter 

 was used as an index of annual abundance and it 

 declined considerably since the early 1980s (Fig. 

 3). Based on the 95% confidence intervals, abun- 

 dances at EN since 1982 have been significantly 

 lower than the 1978 to 1981 period, but were 

 similar to abundance in 1976. 



TABLF 8. Estimated date of peal< abundance for American 

 sand lance based on the inflection point of the Gompertz 

 function for stations EN and NB. 



To determine if the decline of larvae in the 

 Millstone area was localized, data on sand lance 

 were examined from other areas (Table 9). Their 

 abundance in the NMFS spring trawl survey data 

 showed a similar decrease to levels reported in 

 the mid 1970s. Larval densities reported for the 

 waters off the SNPS were variable and declined 

 from the early 1980s but not as evident as seen 

 in the vicinity of MNPS. Similar to the MNPS 

 program, few sand lance were taken in SNPS 

 trawls, but there was an apparent decline in the 

 annual CPUE. From these comparisons, it was 

 apparent that decreasing sand lance abundance 

 occurred regionally. Apparently, adult sand lance 

 abundance has greatly fluctuated along the North- 

 east Atlantic coast during the last 20 years. Meyer 



Fish Ecology Studies 267 



