FISHERY BULLETIN: VOL. 82, NO. 2 



relatively depauperate; the area effect was sig- 

 nificant at P < 0.07 (ANOVA); the time within 

 area effect was significant at P < 0.05 (Table 3). 



Limulus polyphemus occurred in 70% to 100% of 

 all tows between Cape May and Absecon Inlet 

 (Table 3). Crabs were most numerous from to 1.8 

 km offshore between Cape May and Hereford In- 

 lets. When sampled on 15 June (23 stations), there 

 was an average of 15.52 crabs/ST, but in late 

 August-early September (9 stations), only 2.17 

 crabs/ST (F = 5.006, P < 0.05). Abundance from 

 1.8 to 3.7 km between Cape May and Townsends 

 Inlets declined over the same time, from 13.08 to 

 3.3 crabs/ST (F = 4.805, P < 0.05). From 1.8 to 3.7 

 km offshore, between Townsends Inlet and Abse- 

 con Inlet, crabs declined between early July (x = 

 25.33, n = 6), late July-early August {x = 3.95, n 

 = 14), and late August (x = 7.6, n = 5), but the 

 differences were marginally significant [F = 3.03, 

 0.10 <P < 0.05). 



Horseshoe crabs were encountered in every tow 

 in the first 1.8 km from Beach Haven Inlet to Bar- 

 negat Inlet, although the average abundance was 

 only 5 crabs/ST. No other area north of Atlantic 

 City contained over 4 crabs/ST and an onshore- 

 offshore gradient was particularly evident be- 

 tween Beach Haven Inlet and Shark River Inlet. 



TABLE 3. — 1977 Limulus polyphemus survey results. Area 

 means are expressed as the number of crabs per standard tow, 

 as defined in the text. CV = coefficient of variation. Data were 

 log transformed prior to Analysis of Variance. Area locations 

 are shown in Table 1. 



Distance 

 offshore 



Area 



N sta- 

 tions 



% with 

 crabs 



Mean 



CV 



Maximum 



From 1.8 to 3.7 km offshore, crabs were found in 

 only 40% of the tows, and from 3.7 to 5.5 km, no 

 crabs were present at seven stations. 



1978 Survey 



As in 1977, the areas north of Beach Haven Inlet 

 were sampled late in the summer. Stations south 

 of Atlantic City had many more horseshoe crabs 

 than ones farther north, and from Beach Haven 

 Inlet northward, few animals were encountered 

 offshore of 1.8 km (Table 4). Area and time within 

 area effects were significant (ANOVA, P < 0.01; 

 Table 4). 



Temporal variability within an area was dif- 

 ficult to analyze, because for most areas, either 

 the survey was completed in a single weekend, 

 there were low densities on all dates (north of 

 Beach Haven), or there were small sample sizes on 

 one or more cruises. Between Cape May and 

 Townsends Inlet, from 3.7 to 5.5 km offshore, there 

 were significantly more crabs on 20 July (x = 

 12.64, n = 11) than on 24 June (x = 3. 11, n =9)(F = 

 26.998, P < 0.001 1. 



1979 Survey 



In contrast to 1977 and 1978, sampling of the 

 Beach Haven Inlet to Shark River Inlet region 



TABLE 4. — 1978 Limulus polyphemus survey results. Area 

 means are expressed as the number of crabs per standard tow, 

 as defined in the text. CV = coefficient of variation. Data were 

 log transformed prior to Analysis of Variance. Area locations 

 are shown in Table 1. 



386 



