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Fishery Bulletin 96(2), 1 998 
Figure 6 
Length-frequency distributions of northern searobins (open 
bars) and striped searobins (filled bars) for the Massachu- 
setts coastal survey. Sampling periods are the same as those 
shown in Figure 3. rc=number of fish. 
Murawski reported that after an anomalously warm 
period in the 1970’s (when northern searobin abun- 
dance did increase) temperatures in the 1980’s fluc- 
tuated without a trend (but northern searobin abun- 
dance declined dramatically; see Fig. 8). 
The indices of stratified mean weight per tow be- 
tween the Mid-Atlantic Bight (NMFS) and the Mas- 
sachusetts (MDMF) surveys were compared to ex- 
amine how robust these measures of abundance were. 
Correlation analyses revealed a significant relation 
between northern searobin abundance in spring 
(r s =0.51, P=0.032, n=18) between the two surveys, 
but autumn abundances in similar years were nega- 
tively correlated between the two surveys (r s =-0.60; 
P=0.QQ8, n = 18). There was a significant relation be- 
tween these surveys for striped searobin abundance 
in spring (r, =0.51, P=0. 029, n=18) but not for autumn 
(r s =0.077, P= 0.76, n = 18). These significant, positive 
relations between the two surveys support our use 
of spring but not autumn indices for examining north- 
ern and striped searobin population trends. 
implications for fishery ecology 
Northern and striped searobins belong to a “warm- 
temperate” group (Musick et ah, 1989), an assem- 
blage that migrates onshore and north as tempera- 
tures increase, offshore and south as temperatures 
Figure 7 
Length-frequency distributions of northern 
searobins (open bars) and striped searobins 
(filled bars) during five consecutive cruises for 
the New Jersey coastal survey (Table 2). Sam- 
pling periods are the same as those shown in 
Figure 4. n=number of fish. 
decline. Our descriptive analysis supports this char- 
acterization of both species but reveals interspecific 
differences in the timing and extent of seasonal move- 
ments, as well as in size and abundance. Selection of 
sampling strata for calculating abundance indices 
was constrained by our goal to compare the ecology 
of both species. Nevertheless, indices from spring 
cruises in the Mid-Atlantic Bight and along the Mas- 
sachusetts coast were significantly and positively 
