Abstract.— Commercial landings 

 data and research-vessel survey data 

 collected by the Northeast Fisheries 

 Science Center during 1982-86 were 

 analyzed to identify spatial and tem- 

 poral patterns as well as possible 

 mechanisms associated with juve- 

 nile cod Gadus morhua distribution. 

 Analysis of survey data indicated 

 that cod ages 1-2, age 3, and age 4 -i- 

 were distributed at different depths 

 during the spring; however, during 

 the autumn, age-3 fish co-occurred 

 with age 1-2 fish. 



Analysis of commercial landings 

 data revealed the following patterns 

 of distribution for age-2 cod: In 

 quarter 1, concentrations appeared 

 in the Nantucket Shoals region and 

 the central portion of Georges Bank; 

 in quarter 2, the concentration was 

 northeast of Nantucket Shoals and 

 also remained on Georges Bank; in 

 quarter 3, both aggregations moved 

 northeastward into deeper waters, 

 along the 100 m contour of the Great 

 South Channel and the Northern 

 Edge, respectively; and in quarter 4, 

 the Nantucket Shoals concentration 

 had moved southwestward to shal- 

 lower water, resuming locations iden- 

 tified in quarter 1 , while the Georges 

 Bank concentration remained as in 

 quarter 3. 



While intraseasonal spatial distri- 

 butions did not appear to be defined 

 by temperature, seasonal shifts in 

 concentration of juvenile cod were 

 most likely associated with temper- 

 ature. 



Spatial and temporal distribution of 

 juvenile Atlantic cod Gadus morhua 

 in the Georges Bank-Southern 

 l\le\A/ England region 



Susan E. Wigley 



Fredric M. Serchuk 



U/oods Hole Laboratory, Northeast Fisheries Science Center 



National Marine Fisheries Service. NOAA 



166 Water Street. Woods Hole. Massachusetts 02543-1097 



Manuscript accepted 20 May 1992. 

 Fishery Bulletin, U.S. 90:599-606 (1992). 



The Atlantic cod Gadus rnoriiua has 

 accotinted for more catch, by weight, 

 than any other species in the U.S. 

 Atlantic coast groundfish fishery dur- 

 ing the past two decades (Serchuk 

 and Wigley In press). Recent declines 

 in annual landings of cod from the 

 Georges Bank-Southern New Eng- 

 land region (N. Atl. Fish. Org. Div. 

 5Z) have generated concern for the 

 fishery. Total nominal catches (U.S. 

 and Canadian commercial landings, 

 plus U.S. recreational catch) from 

 this area dropped from a high of 

 64,000 metric tons (t) live weight in 

 1982, to 27,900 t in 1986. Although 

 catches increased to 33,700 1 in 1987, 

 64% of the catch in numbers and 36% 

 in weight consisted of age-2 fish from 

 the strong 1985 year-class (NEFSC 

 1988). Of the various commercial 

 market categories of cod, 'scrod' 

 generally represents the smallest size 

 grouping of cod landed. Scrod land- 

 ings paralleled the general decline of 

 Georges Bank cod landings, decreas- 

 ing from 8100 t in 1982 to 3400 t in 

 1986. In addition, Northeast Fish- 

 eries Science Center (NEFSC) re- 

 search-vessel survey abundance in- 

 dices for spring and autumn 1987 

 were among the lowest observed for 

 cod in the 25-year survey time-series 

 (Serchuk and Wigley In press). 



During the period December 1986- 

 March 1987, anomalously high dis- 

 card rates of juvenile cod below the 

 legal minimum landed size of 19 inches 



(48.3cm) TL were associated with 

 commercial trawling operations using 

 small mesh in the Nantucket Shoals 

 area. This high discard level led to an 

 emergency action extending large 

 mesh regulation (5.5-inch mesh in 

 codend) to this region during 23 Feb- 

 ruary-31 March 1988 to "reduce 

 fishing effort and mortality on juve- 

 nile Atlantic cod stocks found in high 

 concentrations in this area at this 

 time" (Federal Register, 50 CFR 

 Part 651, 26 Feb. 1988). Large mesh 

 regulation was permanently extended 

 to the Nantucket Shoals area in Jan- 

 uary 1989 (Federal Register, 50 CFR 

 Part 651, 31 Jan. 1989) (Fig. 1). In 

 addition, the "Nantucket Shoals 

 scrod slaughter" may have prompted 

 the development and implementation 

 of the Flexible Area Action System 

 (FAAS) by the New England Fishery 

 Management Council (NEFMC) and 

 the National Marine Fisheries Ser- 

 vice (NMFS). Under this plan, the 

 Regional Director, NMFS Northeast 

 Region, cotild close an area to fishing, 

 impose mesh size restrictions, or es- 

 tablish catch limits for a period of 3 

 weeks to 6 months to minimize dis- 

 cards of juvenile fish. This represents 

 a significant departure from the tra- 

 ditional uses of seasonal or areal clos- 

 ures, such as protection of adult had- 

 dock Melanogrammus aeglefinics dur- 

 ing spawning (Halliday 1987). 



For such a plan to be effective, 

 knowledge of fish distribution pat- 



599 



