MFR PAPER 1283 Sea Scallop Resources off the Northeastern U.S. Coast, 1975 CLYDE L. MacKENZIE, Jr, ARTHUR S. MERRILL, and FREDRIC M. SERCHUK INTRODUCTION tion distribution, length and age com­ scallops on Georges Bank and the Mid­ position, and growth rates have been dle Atlantic Shelf. The sea scallop, Placopecten magel­ monitored. The St. Andrews Biological MATERIALS AND METHODS lanicus (Gmelin), is one of the com­ Station, New Brunswick, Canada, has mercial mollusks off the Atlantic coast also surveyed sea scallops on Georges Two sea scallop surveys on the RV of the United States and Canada. It is Bank. (Caddy, 1975; pers. commun.). Albatross IV extended from Georges harvested over its entire range, which An early survey of sea scallops on the Bank southward to Cape Hatteras in extends from the Gulf of St. Lawrence Middle Atlantic Shelf was made by the 1975. A standard lO-foot (3.05-m) sea (Posgay, 1957) to south-southeast of U.S. fisheries schooner Grampus in scallop dredge with a bag of 2-inch Cape Hatteras, N. C. (Porter, 1974). 1913 (Anonymous, 1914); a later one (5.08-cm) rings was used. Tows were Historically, the largest harvests by by the RV Delaware in 1960 (Merrill, of 15-minute duration at 6.3 km/hour U.S. fishermen have been from 1962). (3.5 knots). Scallop numbers, condi­ Georges Bank with smaller harvests The objectives of the 1975 surveys tion of the gonads, and shell lengths from the Gulf of Maine, Cape Cod Bay, were to make observations on the dis­ were recorded. Gonadal condition was and the Middle Atlantic Shelf, but since tribution and abundance, spawning determined using criteria established by 1975, more than 60 percent of the total season, and length frequency of sea Posgay and Norman (1958). Gonads U.S. scallop harvest has been from the latter area. Canadian fishennen harvest sea scallops from Georges Bank north­ ward to the Gulf of St. Lawrence. In Figure I.-Historical landings of sea scallops by U.S. fishermen. Sources: Lyles 1976, 8,712 metric tons of sea scallop (1969); Fishery Statistics of the United States (1968-73); Fisheries of the United meats were landed by U. S. fishermen States (1974-75); ICNAF (1977). (ICNAF, 1977), a quantity more than three times larger than that landed in 12 any year between 1969 and 1974 (Fig. 11 1); the Canadian landings were a record '0 high. <f) !;< 9 The Woods Hole Laboratory of the w Northeast Fisheries Center has studied ::Ii u. sea scallop stocks on Georges Bank o ~7 regularly since the late 1950's. Popula- Mo ;; 6 Clyde L. MacKenzie, Jr. is with the Sandy Hook Laboratory, Northeast Fisheries Center, National Marine Fisheries Service, NOAA, High­ lands, NJ 07732. Arthur S. Merrill and Fredric M. Serchuk are with the Woods Hole Laboratory, Northeast Fisheries Center, National Marine Fisheries Service, NOAA, Woods 1930 34 36 42 46 50 54 5. 62 66 70 74 Hole, MA 02543. YEAR February 1978 /9 ° NO SCALLOPS UNDER% BUSHEL NORTHEAST TO < 2 BUSHELS " % "". PIAK • 2 TO < 4 BUSHELS • \/ 42° • 4 TO 8 BUSHELS • i SMAll SCALLOP 1 DISTRIBUTION ". ./ /. ./ -' . SOUTH ( CHANNEL ... ,. SOUTHEAST PART \ ( .' .,/ / o~ ..../ 41° (J/. :-. :/- /--_.j " "" SOUTHWE5f 'An..V"..'" ..1-'. .: .. ....,...•..•... _.\~ SEA SCALLOP DISTRIBUTION-GEORGES BANK R/V ALBATROSS IV CRUISE 75-11 ........... ~--- SEPTEMBER 23 - OCTOBER 3,1975 " 501", 40° 70° 69° 68° 67° 66° Figure 2.-Station pallem and sea scaJJop distribution and abundance (bushels per IS-minute tow) on selected areas of Georges Bank. 23 September to 3 October 1975. Solid lines indicate probable limits ofdistribution of small scallops, mostly the 1972 year class. were divided into those spawned and tween eastern Long Island, N. Y., and stations averaged 0.4 bushels (range not spawned. Between 42 and 130 Cape Hatteras, N.C. 0-4.0 bushels) of scallops per tow. males and 51 to 116 females were ex­ Solid lines encircling areas of dis­ amined at five stations over the sur­ RESULTS tribution of small scallops, most of veyed area. The depths of the stations which belonged to the 1972 year class, Georges Bank were near the mean depth for scallops are also shown on Figure 2. Small scal­ on Georges Bank and the Middle Atlan­ Distribution and Abundance lops were taken at about two-thirds of tic Shelf. Temperature data were col­ stations on the Northern Edge, at all the lected from bathythermographic casts. The distribution of sea scallops sur­ Northeast Peak stations, and at about A total of 144 stations, mostly veyed on Georges Bank is shown in one-third of stations in the Southwest spaced about 8 km apart, was sampled Figure 2. Scallops were taken at 118 of Part and the South Channel. on Georges Bank between 23 Sep­ the 144 stations, on bottoms consisting Scallops were collected at depths that tember and 3 October 1975. Station of various combinations of sand, gra­ ranged from 37 to 100 m (two scallops depths ranged from 22 to 183 m. Sta­ vel, rocks, boulders, and shells of dead were caught at 183 m); mean depth for tions were in three sections of known mollusks-mostly surf clam, Spisula scallops was about 68 m: scallop abundance: I) Northern Edge solidissima (Dillwyn); ocean quahog, and Northeast Peak, 2) Southwest Part, Artica islandica (Linne); and sea scal­ Depth range Scallops and 3) South Channel. A survey of the lop. (m) (percent) 37-50 13 southeast part of Georges Bank was The abundance of sea scallops on 50-75 54 planned, but hurricane threats limited Georges Bank is indicated in Figure 2. 76-100 33 sampling operations. The largest collections were made on A total of 99 stations was sampled the Northern Edge and Northeast Peak, on the Middle Atlantic Shelf between 7 where stations averaged 1.2 bushels Spawning Season and 16 August 1975. Station depths (range, 0-7.5 bushels) (I bushel = 35.2 ranged from 26 to 148 m. Stations were liters) of scallops per tow. In the The gonadal condition ofthe scallops spaced along and among eight transects Southwest Part, stations averaged 0.75 indicated that spawning was in progress that were nearly perpendicular to shore bushels (range, 0-2.0 bushels) of scal­ in late September and early October. and equidistant from each other be- lops per tow. In the South Channel, The percentages of scallops that had 20 Marine Fisheries Review (IN) GEOAGES flANK \ o \\~. \ - ° . IOOrm -- .-'40° ." \ 0 CD . \ • • \ .', . " ., /-' . '. o@ .", tew) . ., . Figure 3.-Length-frequency histograms of sea scallops from three sections of Georges !~ 38' Bank. Number of scallops measured is indi­ cated. ·.1.~-.. ~)® SEA SCALLOP DISTRIBUTION-MIDDLE ATLANTIC SHELF R/V ALBATROSS IV CRUISE 75-8 spawned and the bottom temperatures AUGUST 7 -16,1975 -. --. __ .~® by section were: ° NO SCALLOPS UNDER 1;2 BUSHEL Bonom Percent spawned TO < 2 BUSHELS Depth temper- • • 112 Section Males Females ~ ature ('C) • ° • 2 TO < 4 BUSHELS Northern edge 60.2 36.6 68 11.2 SMALL SCALLOP DISTRIBUTION Southwest part 2.8 10.4 68 10.0 South channel SO.O 41.2 60 9.0 MAJOR TRANSECTS Collectively, the samples contained 216 males and 219 females, a I: I sex ---@ ratio. Length Frequency 76° 74° 72° 70° Figure 3 shows the length-frequency histograms of sea scallops within the Figure 4.-Station pattern and sea scallop distribution and abundance (bushels per IS-minute tow) on the Middle Atlantic Shelf. 7-16 August 1975. Solid lines indicate three sampled sections of Georges probable limits of distribution of small scallops, mostly the 1972 year class. Bank. A significant number of scallops ranged between 3.0 and 7.0 cm long; most represented the 1972 year class. consisting of sand and sand-gravel. als ranging from 3.0 to 8.0 centimeters Within the surveyed sections, the ap­ Scallops were distributed closer to long. and was offshore of the Vir­ proximate percentages of scallops be­ shore at the northern end than at the ginia-North Carolina border. tween 3.0 and 7.0 cm were: Northern southern end of the shelf. The south­ Small scallops that belonged mostly Edge and Northeast Peak, 28 percent; ernmost collection of scallops was to the 1972 year class were taken at half Southwest Part, 2 percent; and South taken off Oregon Inlet, N.C. (lat. the stations; their distribution is shown Channel, 50 percent. 35°53'N, long. 74°55'W). by solid lines in Figure 4. Small scal­ The abundance of sea scallops on the lops were distributed over nearly the Middle Atlantic Shelf Middle Atlantic Shelf is indicated in full width of the sampling area from Distribution and Abundance Figure 4. The largest collections were mid-Long Island to the mouth of Ches­ made south of Long Island and east of apeake Bay. In addition, they were also The distribution of sea scallops sur­ New Jersey where six stations had be­ found in two other discrete areas; one veyed on the Middle Atlantic Shelf is tween 1.0 and 2.0 bushels of scallops off the southeastern tip of Long Island shown in Figure 4. Scallops were taken per tow. The largest collection, 2.5 and another off Albemarle Sound, N. C. at 57 of the 99 stations, on bottoms bushels, consisted mostly of individu- Scallops were collected at depths that February /978 2/ {ItII ranged from 31 to 80 m (one scallop city ofolder year classes may lead to the 1 2 .. 5 e -~ was collected at 110m), mean depth for 1972 year class being overfished. ..r- --+---I.-,,,,,-,,-,,::=l scallops was about 55 m: Spawning Season i ,nc '"''' I Depth range Scallops 12 J N=t> '~7 I (m) (percent) The time of sea scallop spawning has 31·50 248 been infrequently documented.