185 



Areas, depths, and times of high discard rates 

 of scup, Stenotomus chrysops, during 

 demersal fish trawling off the 

 northeastern United States 



Steven J. Kennelly 



Manomel Center for Conservation Sciences 

 PO. Box 1770, Manomet, Massachusetts 02345 

 Present address: NSW Fishenes Research Institute 



PO. Box 21, Cronulla 2230, Australia 

 E-mail address, kennellsigfisheries. nsw.gov.au 



In the waters off the northeastern 

 United States, many stocks of com- 

 mercial and recreational species 

 have declined in recent years (An- 

 thony, 1993; Sissenwine and Rosen- 

 berg, 1994; Collins, 1995; Ma- 

 tthiessen, 1995; NEFSC, 1995). Al- 

 though much of the blame for these 

 declines is ascribed to sustained 

 overfishing, there also has been 

 substantial concern over bycatch 

 and discarding practices in key 

 fisheries of the region, especially 

 those involving demersal trawling 

 (Murawski, 1994; Howell and 

 Langan, 1987, 1992; Cadrin et al., 

 1995; Kennelly et al., 1997). 



For many years scup (or porgy, 

 Stenotomus chrysops) has been an 

 important commercial species in 

 the mid-Atlantic and southern New 

 England regions, caught princi- 

 pally by otter trawling and to a 

 lesser extent by pound nets, float- 

 ing trap nets, and fish traps (Shep- 

 herd and Terceiro, 1994). Like 

 many other key species in the re- 

 gion, annual commercial landings 

 of this species have declined mark- 

 edly in recent years from between 

 18,000 and 27,000 metric tons (tl 

 in the 1950s and 60s to 6000 t in 

 1992 and 4400 t in 1993 (NEFSC, 

 1995). There is also an important 

 recreational fishery for scup in this 

 region, and recreational landings in 

 recent years have accounted for 20 



to 50'7f of the total annual catch. 

 These have also declined from an 

 estimated 3,100 t in the 1980s to 

 2100 t in 1992 and 1300 t in 1993 

 (NEFSC, 1995). Scientists at the 

 1995 Northeast Regional Stock As- 

 sessment Workshop for the scup 

 stock in this region concluded that 

 1) it is currently overexploited; 2) 

 it is at a low level of biomass; and 

 3 ) current high rates of exploitation 

 of age 0-2 fish should be decreased 

 as much as possible (NEFSC^ ). 



As predicted by Wilk and Brown 

 (1980) some time ago, one of the 

 causes of mortality for young scup 

 in this region is thought to be the 

 incidental bycatch and subsequent 

 discarding of this species from de- 

 mersal trawlers that target other 

 species, particularly squid (Loligo 

 spp.). McKiernan and Pierce's^ 

 study of the inshore squid fishery 

 in Nantucket and Vineyard Sounds, 

 Massachusetts, showed significant 

 discard of scup but, like Cadrin et 

 al. (1995), they concluded that the 

 inshore abundances of this species 

 were more probably related to trawl 

 effort throughout the region than to 

 the relatively small effort of inshore 

 squid trawlers. They concluded 

 that significant numbers of small 

 scup may be discarded by squid 

 trawlers farther offshore where scup 

 are known to migrate in the autumn 

 (see also Finkelstein, 1971; Eklund 



and Targett, 1990) and recom- 

 mended an examination of the dis- 

 carding practices of these trawlers. 



The most reliable way to quan- 

 tify discards in commercial fisher- 

 ies is for observers to record data 

 during normal fishing operations 

 (e.g. Jean, 1963; Powles, 1969; 

 Young and Romero, 1979; Atkinson, 

 1984; Murawski et al., 1995). Infor- 

 mation from such programs is a 

 necessary prerequisite for the two 

 main management alternatives 

 used to reduce discards: 1) spatial 

 and temporal closures to fishing in 

 areas and times of high rates of dis- 

 card of key species (i.e. discard "hot- 

 spots") (Murawski, 1992; Hendrick- 

 son and Griffin, 1993; Alverson et 

 al., 1994, Kennelly, 1997); and 2) 

 modifications to fishing gears and 

 practices that improve selectivity 

 (Robertson and Stewart, 1988; 

 Isaksen et al., 1992; Hall, 1994; 

 Broadhurst et al., 1996; Broadhurst 

 and Kennelly, 1997). 



Since 1989, the National Marine 

 Fisheries Service's Northeast Fish- 

 eries Science Center (NEFSC) has 

 operated a large-scale observer pro- 

 gram in many of the fisheries off 

 the northeastern United States 

 from Maine to North Carolina 

 (Murawski etal., 1995; Kennelly et 

 al., 1997). The data collected from 

 demersal trawlers in this program 

 have provided an opportunity to 

 examine the spatial and temporal 

 occurrences of discarded scup in the 

 offshore mid-Atlantic and southern 

 New England trawl fishery. 



' NEFSC (Northeast Fisheries Science 

 Center). 1995. Report of the 19th 

 northeast regional stock assessment work- 

 shop-the plenary. NOAA/NMFS/NEFSC, 

 Woods Hole, MA. NEFSC Ref Doc. 95-09, 

 57 p. 



- McKiernan, D. J., and D. E. Pierce. 

 1995. Loligo squid fishery in Nantucket 

 and Vineyard Sounds. Massachusetts 

 Div. Fish. Publ. 17648-75-200-1/95-3.47- 

 CR, 62 p. 



Manuscript accepted 7 April 1998. 

 Fish. Bull. 97:185-192 (1999). 



