NOTE Chittenden et al.: Spatial and temporal occurrence of Scomberomorus maculatus 



155 



Figure 4 



Estimates of daily Spanish mack- 

 erel Scomberomorus maculatus 

 catch-per-unit-effort (C/f, no. of 

 22.6kg boxes landed), June- 

 August 1989 by location. Com- 

 paratively few or no fish were 

 landed March-May and Septem- 

 ber-November, (x) Lynnhaven, 

 (▲> lower York River, (•) 

 Reedville, (O) Eastern Shore. 



Table 4 



Summary, by month, of Tukey's multiple comparisons tests to 

 evaluate specific differences between areas in Spanish mack- 

 erel Scomberomorus maculatus catches in 1989. Mean ranks 

 (of scores for catch-per-unit-effort, see Methods) without the 

 same letters are significantly different at a=0.05. There were 

 no significant differences in months not tabulated. 



Area 



Mean 

 rank 



Significance 



June 



Lynnhaven 

 Reedville 

 Eastern Shore 



July 



Lynnhaven 

 York River 

 Reedville 

 Eastern Shore 



11.50 

 6.40 

 4.75 



9.63 

 9.25 

 3.50 

 3.50 



a 



a b 



b 



the waters of Virginia. We found regular occurrences 

 at Reedville near the Potomac River mouth, occasion- 

 ally in high numbers as noted by Uhler & Lugger 

 (1876), although Hildebrand & Schroeder (1928) re- 

 ported few occurrences north of the Rappahannock 



River. Many fish may enter Maryland waters in years 

 of abundance (Butz & Mansueti 1962), such as in 1880 

 when landings were 8.2 1 (Earll 1883). However, catches 

 there have always been small compared with those in 

 Virginia, where landings made up 97-99% of the re- 

 ported bay- wide catch in 1880 (Earll 1883), in 1920 

 (Hildebrand & Schroeder 1928), in 1887-1967 (Lyles 

 1969), and in 1968-76 (Trent & Anthony 1979), and in 

 1978-90 (from annual printouts, "(Year) landings for 

 the U.S.," provided by the NMFS Office of Data Infor- 

 mation Management to VIMS library). 



Spanish mackerel may be abundant throughout 

 much of the Chesapeake Bay in Virginia. Large pound 

 and gillnet fisheries existed for it in the 1880s off 

 Gloucester and Mathews counties on the Western 

 Shore, off the Eastern Shore from Cape Charles to 

 Crisfield MD, and off Tangier Island VA (Earll 1883 

 and 1887, McDonald 1887). Fish also enter the more- 

 saline, lower parts of tributaries like the Potomac and 

 York Rivers (Baird cited in Goode 1888, Hildebrand & 

 Schroeder 1928). 



Though they may be useful for management and 

 environmental impact assessment, little data exist to 

 describe in fine detail the spatial distribution of Span- 

 ish mackerel in Chesapeake Bay. Such data would be 

 difficult and probably expensive to obtain without man- 

 datory catch-reporting by all the commercial fisheries, 

 because this is a pelagic, fast-swimming, and widely- 

 distributed species that is not well suited to most 

 fishery-independent collecting programs. However, the 

 large-scale distributional patterns of this species ap- 

 parently have been stable for over 100 years. Our data, 

 biological notes, and anecdotal information from the 

 years 1870-80 (Uhler & Lugger 1876, Earll 1883 and 

 1887, McDonald 1887) and 1920-60 (Hildebrand & 

 Schroeder 1928, Butz & Mansueti 1962), and long- 

 term landings data from Maryland and Virginia indi- 

 cate that this species primarily occupies waters which, 

 according to Lippson & Lippson (1984), are of poly- 

 haline salinity ( 18-30 ppt) and the saltier portions of 

 mesohaline waters (5-18 ppt). 



