8 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Close examination of the available records reveals that the abundance of striped 

 bass on the Atlantic coast has shown tremendous fluctuations over a long period of 

 years. As will be shown below (see p. 13), this is because the striped bass is subject 

 to year-class dominance, a phenomenon which has received increasing attention in 

 the past quarter century, since it has been found to apply to so many different species. 

 Briefly explained, year-class dominance may be said to be the production of such 

 unusually large quantities of any species in a single year that the members of this age- 

 group dominate the population for a considerable period, and are noticeably more 

 abundant than the individuals produced in the preceding and following years. Such 

 dominant year-classes usually make their appearance only at fairly lengthy intervals. 



Year-class dominance in any species does not, of course, insure the maintenance 

 of the population at a consistently high level. It is also clear that dominant year- 

 classes are often produced by a comparatively small parental stock (see p. 14), and 

 that therefore — at least down to a certain point — their appearance is not correlated 

 with an unusual abundance of mature and spawning fish. There may even be an 

 inverse correlation between these two factors— that is, a large production in any season 

 by a comparatively small population of mature individuals. Such a correlation has 

 been suggested by Bigelow and Welsh (1925) for the mackerel (Scomber scombrus), 

 the "years of great production always falling when fish are both scarce and average 

 very large ..." This phenomenon is probably most common in particularly prolific 

 species that produce a large number of eggs. Such a species is the striped bass, and 

 such a production of a dominant year-class took place in 1934 (see p. 11). 



In the case of the striped bass a study of the size of the stock over short-term 

 periods may, therefore, be most deceptive. Thus the first manifestation of a large 

 year-class might give the impression of increasing abundance, or, if the study started 

 shortly after an exceptionally productive year, a sharp decline in the population 

 would be apparent under the conditions of the existent intensive fishery. To get a 

 true picture of the trend in abundance, it is therefore essential to study the fluctua- 

 tions over long-term periods. 



Accurate catch records, which form the most reliable means of studying the rel- 

 ative size of the population in different periods, are unfortunately not available 

 farther back than the latter half of the nineteenth century. Bigelow and Welsh 

 (1925), however, state: "... that a decrease was reported as early as the last half 

 of the eighteenth century." Nor is it surprising that such a decline was noticed so 

 long ago°when it is considered that the striped bass is a strictly coastwise species, 

 and one that is easily available throughout the year. If haddock (Melanogrammus 

 aeglefinus) (Herrington, 1935), halibut (Hippoglossus hippoglossus) (Thompson and 

 Herrington, 1930), and other offshore fishes have become scarcer through the in- 

 tensity of fishing, and this is admitted, it is much more likely that a purely coastal 

 species such as the striped bass, which is far more accessible and therefore unceas- 

 ingly the object of fishermen's attention, should soon have shown a marked decrease 

 in numbers. Also, the availability of the striped bass and the resultant heavy drain 

 on the stock is not the only factor involved. Since this fish is anadromous, there 

 has been every chance for civilization to do irreparable damage to valuable spawn- 

 ing areas. There is abundant evidence to show that such destruction has often 

 occurred (see p. 16). In view of these facts it was not an unreasonable expecta- 

 tion that the supply should soon have diminished, and that in spite of the produc- 

 tion of dominant year-classes the stock could not be maintained at its original high 



level. 



Even in the absence of catch records or figures to prove the point, there can be 

 no question but that the numbers of striped bass along the Atlantic coast have de- 

 creased during at least the past 2 centuries. There have undoubtedly been periods 

 when the population showed sudden and pronounced increases, presumably due to 

 the presence of unusually good year-classes. But these peaks have probably been 

 short-lived, and the general trend over long periods has been downwards. 



Two series of accurate catch records going back to the latter half of the nineteenth 

 century have been made available to the author. Both of these bear out the above 

 contention and substantiate such a hypothesis. The first record is that of the numbers 

 of striped bass taken annually from 1865 to 1907, on rod and line, by the members of 



