Grubby 



The grubby is found in coastal waters, com- 

 monly in eelgrass habitats, along the Atlantic 

 coast of North America from the Gulf of St. 

 Lawrence to New Jersey (Bigelow and Schroeder 

 1953). They spawn throughout the winter (Lund 

 and Marcy 1975) and Richards (1959) reported 

 finding larvae in shallower areas of US from Feb- 

 ruary to April. The grubby tolerates a wide range 

 of temperatures and salinities (Bigelow and 

 Schroeder 1953). 



The grubby is a resident in the Millstone area 

 and both larvae and adults were collected in the 

 monitoring programs. However, eggs were rarely 

 taken because they are demersal and adhesive 

 (Lund and Marcy 1975). Juveniles and adults 

 were rarely collected in the shore zone by seine. 



Grubby larvae accounted for about 4% of the 

 total larval collection in entrainment samples (Ta- 

 ble 4). Annual entraiimient estimates have ranged 

 from 8.9 to 50.0 million and the estimates during 

 three-unit operations were similar to those in pre- 

 vious years during the 1980s, even with the addi- 

 tion of Unit 3 (Table 16). Larvae were collected 

 at both EN and NB, primarily in February 

 through May and the dates of peak abundance 

 varied from mid March to early April (Table 17). 

 The a parameters calculated from the Gompertz 



TABLE 16. Annual entrainment estimates and 95% confi- 

 dence intervals for grubby larvae at MNPS. 



TABLE 17. Estimated date or peak abundance for grubby 

 larvae based on the inflection point of the Gompertz function 

 for stations EN and NB. 



equation (all R values exceeded 0.98) were used 

 as indices of annual larval abundance (Fig. 9). 

 larvae were most abundant from 1981 to 1983 

 at EN and the abundance during 1984 to 1987 

 decreased to a level similar to the late 1970s. 

 Annual abundance at NB was consistently lower 

 than at EN. Larval abundances during three-unit 

 operation were within the range of historical data 

 at EN and NB. 



In impingement collections, the grubby was the 

 third most abundant taxon, accounting for over 

 1 1 % of the total (Table 4). Most were adults (60 

 to 120 mm) taken during their winter spawning 

 season (December through April). As was found 

 for other species, there was a recent decline in 

 impingement at Unit 2 with the estimated number 

 in 1987 the lowest recorded (Table 2). 



Almost 80% of the grubby taken by trawl were 

 found at the nearshore stations (IN, JC, and NR) 

 (Appendix III). They were collected throughout 

 the year at JC and NR, and primarily during their 

 spawning season at IN. At these stations, 5-mean 

 catches during three-unit operations were within 

 the historical range (Table 18). Highest annual 

 catches at IN and NR occurred in the early 1980s 

 and corresponded to high larval abundance at EN 

 during the same time period. The annual mean 

 length at IN and JC has remained fairly consistent, 

 but at NR mean length decreased during the 

 1980s (Fig. 10). This smaller mean length at NR 



Fish Ecology Studies 277 



