SPAWNING AND FECUNDITY OF ATLANTIC MACKEREL, 

 SCOMBER SCOMBRUS, IN THE MIDDLE ATLANTIC BIGHT 



Wallace W. Morse ' 



ABSTRACT 



Collections of Atlantic mackerel, Scomfcerscomirus, were made during spring 1977 from Maryland to 

 Rhode Island. Length-weight relationships were determined for total and fork lengths and total and 

 gutted weights. Spawning time was determined from gonad somatic indices and peak spawning 

 occurred between 21 April and 4 May. Egg diameter frequencies from running ripe ovaries indicated 

 five to seven egg batches are spawned by each female during the spawning season. Fecundity was 

 estimated and ranged from 285,000 to 1,980,000 for fish between 307 and 438 mm fork length. 

 Fecundity was related to fork length, gutted weight, and age. 



The Atlantic mackerel, Scomber scombrus Lin- 

 naeus, is a schooling, pelagic species ranging from 

 the Gulf of St. Lawrence to North Carolina in the 

 northwest Atlantic and from Norway to Spain in 

 the northeast Atlantic. The northwest Atlantic 

 population has been separated into northern and 

 southern contingents on the basis of size composi- 

 tion, spawning times, summer distributions, and 

 tagging studies (Sette 1950; Moores et al. 1975; 

 MacKay2).The northern contingent spawns in the 

 southern Gulf of St. Lawrence from about the end 

 of May to mid-August (Ware 1977). The southern 

 contingent spawns from mid-April to June from 

 North Carolina to Massachusetts (Berrien 1978). 

 Fecundity estimates of northwest Atlantic 

 mackerel are limited to a few observations rang- 

 ing from about 500,000 to 1,000,000 eggs (Brice 

 1898: 208-213; Sette 1943). Fecundity of northeast 

 Atlantic mackerel ranged from approximately 

 130,000 to 1,100,000 eggs for fish 28.5-46.0 cm 

 total length (Macer^; Lockwood'*). This paper pre- 

 sents the results of a fecundity and spawning time 

 investigation of the southern contingent. 



METHODS 



Atlantic mackerel were collected between 9 

 April and 21 May 1977 from recreational and 



'Northeast Fisheries Center Sandy Hook Laboratory, Na- 

 tional Marine Fisheries Service, NOAA, Highlands, NJ 07732. 



^MacKay, K, T. 1973. Aspects of the biology of Atlantic 

 mackerel in ICNAF Subarea 4. Int. Comm. Northwest Atl. 

 Fish., Res. Doc. 73/70, 11 p. 



^Macer, C. T. 1976. Observations on the maturity and 

 fecundity of mackerel {Scomber scombrus L.) Int. Counc. 

 Explor. Sea, CM 1976/H:6, 7 p. 



■•Lockwood, S. J. 1978. The fecundity of mackerel. Scomber 

 scombrus L. Int. Counc. Explor. Sea, CM 1978/H:9, 5 p. 



commercial catches from Maryland to Rhode Is- 

 land (Table 1). Length frequencies of males and 

 females are shown in Figure 1. All fish were mea- 

 sured to the nearest millimeter fork length (FL) 

 and total length (TL), and weighed to the nearest 

 gram total weight (TW) and gutted or somatic 

 weight (GW). Otoliths were extracted for age de- 

 termination. Ovaries of all mature females were 

 exsected, weighed to the nearest 0.01 g, and pre- 

 served in 10% Formalin.^ 



Preliminary observations of eggs from ovaries 

 in the spawning condition revealed that three egg 

 types were present: 1) small, translucent eggs; 2) 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



Table l. — Catch data of Atlantic mackerel sampled in 1977. 



Manuscript accepted August 1979 

 FISHERV BULLETIN: VOL 



103 



78, NO. 1, 1980. 



