Appendix 3, continued. Species life history notes 



pups after 18-22 month gestation) and the juvenile 

 stage may last >10 years. Individual females produce 

 young only in alternate years. In the Gulf of Maine, 

 mating is assumed to occur in the colder months (Feb.- 

 Mar.) offshore (Bigelowand Schroeder 1 953, Nammack 

 et al. 1985). It has also been suggested that females 

 migrate into shallow water from November to January 

 to bear their young (Jensen 1966, Nammack et al. 

 1985). Nonetheless, there are few recorded observa- 

 tions of parturition and/or mating, and the actual occur- 

 rence of these events in particular estuaries and 

 embayments is somewhat questionable (Jensen 1966). 

 We have reflected this uncertainty by assessing the 

 mating and parturition stages as no information avail- 

 able in some systems. For the purposes of the ELMR 

 program, the spawning stage refers to mating (M) and 

 internal fertilization of eggs; and while no egg or larval 

 stages are recognized, the egg stage (E) is replaced by 

 parturition (P) data. 



• Skates: The most common species of Raja in the 

 inshore areas of the North Atlantic are little skate (R. 

 erinacea), winter skate (R. ocellata), and barndoor 

 skate (R. laevis). Thorny skate (R. radiata) and smooth- 

 tailed skate (R.senta) are less commonly found (Bigelow 

 and Schroeder 1953, Scott and Scott 1988). Skates 

 are oviparous, and generally extrude egg cases shortly 

 after fertilization. Spawning season differs between 

 species. Most species tend to migrate in response to 

 seasonal changes in temperature. For the purposes of 

 the ELMR program, the spawning stage refers to 

 mating (M) and internal fertilization of eggs and the egg 

 stage (E) refers to the period from egg extrusion to 

 hatching. Upon hatching, young skatesare considered 

 juveniles so there is no larval stage. 



• Shortnose and Atlantic sturgeons: Shortnose 

 sturgeon (Acipenserbrevirostrum) is considered to be 

 endangered throughout its range (USFWS 1993) and 

 is protected in Massachusetts and New Hampshire 

 (Johnson 1987). Atlantic sturgeon (Acipenser 

 oxyrhynchus) is protected in Massachusetts (R. 

 Iwanowicz pers. comm.) and is a species of special 

 concern in New Hampshire and Maine (Johnson 1 987). 

 Both species are anadromous, occur primarily in large 

 river systems, are slow growing, and long-lived. Spawn- 

 ing may occur in fresh or brackish water and presum- 

 ably does not occur every year for individual females. 

 Atlantic sturgeon eggs are demersal and adhesive, 

 larvae drift downstream, and juveniles remain in fresh/ 

 brackish water for their first summer, then migrate 

 seaward (Dadswell et al. 1984, Kieffer 1991) Little is 

 known about juvenile stages, which are not caught by 

 the large mesh gillnets used in most surveys. It is 

 unknown if there is migration of adult shortnose stur- 

 geon out of fresh/brackish water areas as is true for the 

 Atlantic sturgeon. In some areas strays have been 



encountered (e.g., shortnose sturgeon in Cape Cod 

 Bay), but are not considered to be regularly present. 



• American eel: Anguilla rostrata is catadromous with 

 spawning occurring in the Sargasso Sea in the spring 

 (Facey and VanDenAvyle 1987). The early pelagic 

 larvae, called "leptocephali," may spend over a year in 

 marine waters before being transported shoreward. As 

 the leptocephali reach the continental shelf, they begin 

 their metamorphosis into transparent "glass eels." As 

 glass eels migrate into estuaries and fresh water, they 

 develop pigment and are considered elvers, which 

 then grow into the "yellow eel" stage. Yellow eels 

 inhabit estuarine and fresh waters for years before 

 maturing into the "silver eel" stage and migrating sea- 

 ward. Forthe purposesof the ELMR program, emigrat- 

 ing silver eels are considered to be adults (A); yellow 

 eels and elvers are considered to be juveniles (J); and 

 glass eels are considered to be larvae (L) (leptocephali 

 are not regularly encountered in the coastal North 

 Atlantic). We retain spawning (S) and egg (E) stages in 

 our data presentation but stipulate that both occur only 

 in offshore waters. 



• Blueback herring and alewife: Alosa aestivalis and 

 A. pseudoharengus are often grouped together as river 

 herring. Spawning occurs in spring, with alewives 

 breeding 3-4 weeks earlier than bluebacks in the same 

 watershed. Spawning habitats also tend to differ, with 

 alewives spawning in slow flowing sections of slightly 

 brackish or freshwater, and bluebacks spawning in 

 more lotic sites (Mullen et al. 1986, Loesch 1987). 

 Alewives are usually more abundant than bluebacks in 

 the northern Atlantic region. Adults typically return to 

 sea after spawning, and may spawn repeatedly in their 

 natal river. Habitat alteration resulting from dams and 

 pollution have historically limited areas available for 

 the spawning of anadromous species throughout New 

 England, and thus many local stocks are reduced from 

 previous levels. Stocking and habitat mitigation pro- 

 grams exist for several rivers to attempt the restoration 

 of target species including river herring. 



• American shad: Alosa sapidissima is an anadro- 

 mous species with a strong natal homing tendency. 

 Adults tend to spawn only once in the freshwater 

 portions of rivers at the southern edge of its range. 

 However, with increasing latitude, the mean age at first 

 spawning increases, the number of eggs spawned 

 decreases, and the number of spawnings per lifetime 

 increase so that a large percentage are iteroparous in 

 the Gulf of Maine. Young of the year spend their first 

 summer in the river/estuary and then migrate to the 

 ocean in the fall. Shad tend to school during their 

 oceanic phase (Weiss-Glanz et al. 1 986, Dadswell et 

 al. 1 987). Johnson (1 987) listed shad as a species of 

 special concern in Maine. 



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