Spatial and temporal occurrence of 

 Spanish mackerel Scomberomorus 

 maculatus in Chesapeake Bay* 



Mark E. Chittenden Jr. 

 Luiz R. Barbieri 



Virginia Institute of Marine Science, The College of William & Mary 

 Gloucester Point. Virginia 23062 



Cynthia M. Jones 



Applied Marine Research Laboratory, Old Dominion University 

 Norfolk, Virginia 23529 



The Spanish mackerel Scombero- 

 morus maculatus is a pelagic, 

 warm-temperate, or subtropical spe- 

 cies that inhabits continental wa- 

 ters from Cape Cod, Massachusetts, 

 south along the Atlantic coast to 

 Florida and through the Gulf of 

 Mexico to the Yucatan Peninsula 

 (Collette et al. 1978, Collette & 

 Russo 1984). In summer, it is con- 

 sidered common along the U.S. east 

 coast north to Chesapeake Bay 

 (Bigelow & Schroeder 1953, Musick 

 1972). This species was abundant 

 in Chesapeake Bay in the late 

 1800s, and the most extensive fish- 

 ery for it in the U.S. occurred there 

 then (Earll 1883). In recent years, 

 Spanish mackerel have again be- 

 come abundant in Chesapeake Bay 

 (Chittenden et al. In review). 



Much work has been done on 

 Spanish mackerel (see Berrien & 

 Finan (1977) and Lukens (1989). 

 However, other than Chittenden et 

 al. (In review), no studies have been 

 directed at this species in the cold- 

 temperate waters north of Cape 

 Hatteras NC, since Ryder (1882) 

 and Earll ( 1883) over 100 years ago. 

 As a result, little information ex- 

 ists from which to plan collection of 

 basic biological data on this species 



'Contribution 1786 of The College of 

 William & Mary, Virginia Institute of 

 Marine Science. 



in the Chesapeake Region, much 

 less to manage it there. 



The objectives of the present 

 study are to describe spatial and 

 temporal distributions of Spanish 

 mackerel in Chesapeake Bay using 

 catch estimates from direct obser- 

 vations of catches and interviews of 

 commercial fishermen, and to relate 

 the temporal distribution of this 

 species to water temperature. This 

 basic information is needed to plan 

 other research on this species in the 

 Bay. 



Methods 



Our data cover the period 1988-90, 

 but primarily 1989, and were ob- 

 tained from commercial pound-net 

 fisheries that cover a broad area of 

 the Virginia waters of Chesapeake 

 Bay (Fig. 1). The individual Chesa- 

 peake Bay fisheries are generally 

 small in scale, usually fishing 1-7 

 nets in the local waters of each 

 fishery. The nets are usually emp- 

 tied daily, depending on wind con- 

 ditions, size of the local catch, and 

 market conditions. Reid ( 1955) and 

 Chittenden (1991) describe the 

 Chesapeake Bay pound-net fisher- 

 ies, e.g., gear, fishing, and catch- 

 processing procedures. 



We present next our sampling de- 

 sign for 1989, the major period of 



study. At weekly or fortnightly in- 

 tervals, we made 51 on-site obser- 

 vations and 66 telephone calls to 

 cooperating fishermen to get daily 

 catch-record information to estimate 

 the size of Spanish mackerel catches 

 at their commercial pound-net fish- 

 eries (see Fig. 2 for the spatial and 

 temporal distribution of these data 

 contacts). We studied four fisheries, 

 which were chosen because they 

 were usually cooperative in provid- 

 ing information, were widely-spaced 

 along the Chesapeake Bay, and 

 were among the major fisheries in 

 their areas. These characteristics fa- 

 cilitated data collection, giving the 

 study widespread geographic cover- 

 age and pertinence to major por- 

 tions of the Chesapeake Bay pound- 

 net fishery. Three of the contacted 

 fisheries were located along the 

 'Western Shore' of Chesapeake Bay 

 (Fig. 1), off (1) Lynnhaven, (2) the 

 lower York River, and (3) Reedville; 

 the fourth was located along the 

 lower 'Eastern Shore' near Kip- 

 topeke. Though not all the nets were 

 emptied every day, in 1989 these 

 fisheries fished 21 pound-nets 

 (Table 1), about 10% of the roughly 

 200 net licenses issued in the 

 Chesapeake Bay pound-net fishery. 

 The pound-net fisheries begin fish- 

 ing each year (and our initial con- 

 tacts were made) well before Span- 

 ish mackerel enter Chesapeake Bay; 

 the fisheries continue operating 

 (and our later contacts were made) 

 well after this species leaves the 

 Bay (see the occurrence of zero 

 catches in Fig. 2). 



Findings in 1989 were supple- 

 mented with information from 1988 

 and 1990, which was obtained us- 

 ing the same sampling design and 

 procedures as in 1989 but with less 

 regular and extensive contacts. In 

 1988 contacts were primarily made 

 in the last half of the fishing sea- 

 son; we used this data to describe 

 when Spanish mackerel disap- 



Manuscript accepted 8 October 1992. 

 Fishery Bulletin, U.S. 91:151-158(1993). 



151 



