151 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
& established in 1881 ■<?. 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Fecundity and reproductive life history 
of anadromous rainbow smelt (Osmerus mordax ) 
in coastal waters of Massachusetts 
Bradford C. Chase (contact author ) 1 
Scott Elzey 2 
Sara M. Turner 1 
Matt H. Ayer 2 
Email address for contact author: brad.chase@mass.gov 
1 Massachusetts Division of Marine Fisheries 
836 South Rodney French Boulevard 
New Bedford, Massachusetts 02744 
2 Massachusetts Division of Marine Fisheries 
30 Emerson Avenue 
Gloucester, Massachusetts 01930 
Abstract— Abundance and harvest 
of rainbow smelt (Osmerus mordax) 
in the northwest Atlantic Ocean have 
declined sharply in recent decades, 
with a concurrent reduction in the his¬ 
toric geographic range of this species. 
These declines have occurred while 
management responses have been 
limited by information gaps on the life 
history of this species. We assessed 
reproductive attributes of rainbow 
smelt caught in marine waters during 
winter and compared their size and 
age characteristics to those of fish 
sampled from spring spawning runs 
in 4 coastal rivers in Massachusetts. 
Total fecundity of rainbow smelt was 
4880-51,651 oocytes. Fecundity was 
positively related with total length 
(TL), total weight, ovarian weight, 
and age. Immature rainbow smelt 
were rarely caught during spawning 
runs but composed 10% of the marine 
samples. This observation, a maturity 
ogive for rainbow smelt from marine 
waters, and differences in TL of age-1 
fish between marine and river samples 
confirm that age-1 rainbow smelt are 
not fully recruited to spawning runs. 
Samples from spawning runs had a 
higher proportion of age-1 rainbow 
smelt, a lower proportion of those age 3 
or older, a higher instantaneous rate 
of total mortality, and a lower number 
of eggs produced per recruit than have 
been previously documented for rain¬ 
bow smelt—all indications of declining 
population health. 
Manuscript submitted 1 August 2018. 
Manuscript accepted 5 July 2019. 
Fish. Bull. 117:151-168 (2019). 
Online publication date: 17 July 2019. 
doi: 10.7755/FB.117.3.3 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The northwest Atlantic Ocean, includ¬ 
ing the Gulf of Maine, is among the 
fastest-warming marine areas in the 
world (Hare et al., 2016). The rain¬ 
bow smelt (Osmerus mordax) is an 
anadromous species that has adapted 
to thrive in cold-water environments 
(Driedzic and Ewart, 2004; Driedzic 
and Short, 2007) and is restricted 
to the northwest Atlantic Ocean. 
Improvements are needed in our 
understanding of the life history and 
population dynamics of rainbow smelt 
to determine conservation strategies. 
The rainbow smelt is a small, short¬ 
lived fish that matures in coastal 
waters and migrates in spring to 
spawn in coastal rivers. This species 
formerly supported important com¬ 
mercial and recreational fisheries in 
the Canadian Maritime provinces 
and the U.S. waters of the Gulf of 
Maine (Goode, 1884; Kendall, 1926; 
Enterline et al., 2012). Rainbow smelt 
fisheries in Massachusetts were regu¬ 
lated for rod-and-reel harvest only for 
most of the 20th century. For estuary 
ice-shack fisheries and fall shoreline 
fisheries, popular more than 30 years 
ago, participation and harvest have 
declined to low levels (Chase 1 ). Rain¬ 
bow smelt can be essential to inland 
aquatic food webs (Kircheis and Stan¬ 
ley, 1981; O’Gorman et al., 1987; Sayers 
et al., 1989) and are considered import¬ 
ant prey for a variety of fish and wild¬ 
life species in coastal rivers and marine 
habitats (Scott and Scott, 1988). 
Overall, diadromous fish species 
have experienced severe population 
declines since the 18th century with 
most species at historically low levels 
of abundance in the northwest Atlantic 
Ocean (Limburg and Waldman, 2009). 
Anadromous rainbow smelt have expe¬ 
rienced a substantial contraction of 
the southern part of their historical 
geographic range (Enterline et al., 
2012), but details on their popula¬ 
tion dynamics and life history remain 
poorly known. In response to concerns 
over populations of rainbow smelt in 
New England, NOAA listed anadro¬ 
mous rainbow smelt as a species of con¬ 
cern in 2004 (Federal Register, 2004). 
1 Chase, B. C. 2006. Rainbow smelt (Osmerus 
mordax) spawning habitat on the Gulf of 
Maine coast of Massachusetts. Mass. Div. 
Mar. Fish. Tech. Rep. TR-30, 173 p. [Avail¬ 
able from website.] 
