142 
National Marine 
Fisheries Service 
NOAA 
Abstract —Migrations of anadromous 
sea lamprey (Petromyzon marinus) 
from marine ecosystems serve as 
vectors of nutrients into freshwa¬ 
ter food webs. Larval sea lamprey 
reside in streams for 6-8 years as 
deposit feeders before metamorphos¬ 
ing into juveniles and migrating to 
the ocean. Previous work has shown 
that carcass nutrients, which result 
from the death of adult lamprey af¬ 
ter spawning, increase stream pro¬ 
ductivity and are consumed by lar¬ 
vae. This may increase larval growth 
rates and enhance earlier metamor¬ 
phosis. We examined the sensitivity 
of life-history parameters and influ¬ 
ence of nutrients from carcasses of 
sea lamprey on the age and growth 
of larval conspecifics with a deter¬ 
ministic stock-recruitment model. 
We hypothesized that variability in 
growth among larval populations is 
productivity mediated and we com¬ 
pared modeled populations in which 
larvae receive added growth benefits 
from carcass nutrients with popula¬ 
tions that do not. The results of our 
simulation indicate that increases 
in larval growth and lower age at 
metamorphosis over time lead to 
an increase in spawner abundance. 
Increased growth rates may also 
improve fitness and bolster subse¬ 
quent spawning stocks. Our research 
characterized 2 potential ecosystem 
states, one in which larval sea lam¬ 
prey benefit from adult conspecifics 
and another in which the larvae do 
not. 
Manuscript submitted 30 June 2017. 
Manuscript accepted 8 January 2018. 
Fish. Bull. 116:142-152 (2018). 
Online publication date: 2 February 2018. 
doi: 10.7755/FB.116.2.3 
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. 
Fishery Bulletin 
fy- established in 1881 •&. 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
The influence of nutrients from carcasses of sea 
lamprey (Petromyzon marinus) on larval growth and 
spawner abundance 
Daniel M. Weaver (contact author) 1 
Stephen M. Coghlan Jr. 1 
Joseph Zydlewski 2 
Email address for contact author: daniel.weaver@maine.edu 
1 Department of Wildlife, Fisheries, and Conservation Biology 
University of Maine 
5755 Nutting Hall 
Orono, Maine 04469 
2 U.S. Geological Survey 
Maine Cooperative Fish and Wildlife Research Unit and 
Department of Wildlife, Fisheries, and Conservation Biology 
University of Maine 
5755 Nutting Hall 
Orono, Maine 04469 
Anadromous fish link freshwater 
and marine ecosystems through the 
seaward emigration of juveniles and 
subsequent immigration of adults. 
These adult fish serve as vectors of 
marine-derived nutrients into fresh¬ 
water via metabolic waste, gametes, 
and the carcasses of dead spawners 
(Gende et ah, 2002; Nislow and Ky- 
nard, 2009; Naslund et ah, 2015). 
The resulting nutrients may have a 
bottom-up effect on freshwater sys¬ 
tems through the stimulation of pri¬ 
mary and secondary production (Wip- 
fli et ah, 2003; Kohler et ah, 2008; 
Weaver et ah, 2016). Concurrently, a 
proportion of liberated nutrients may 
be assimilated by larval and juvenile 
fish that reside in freshwater before 
their migration to the ocean (Lang et 
ah, 2006; Kiernan et ah, 2010; Rinel- 
la et ah, 2012; Weaver, 2017). Unfor¬ 
tunately, dam construction, habitat 
modification, and overfishing have 
reduced or eliminated many popula¬ 
tions of anadromous fish (Saunders 
et ah, 2006; Sheer and Steel, 2006; 
Limburg and Waldman, 2009), by 
severing linkages between freshwa¬ 
ter and marine ecosystems. Reduced 
connectivity diminishes the exchange 
of energy and nutrients and signifi¬ 
cantly alters stream food-web struc¬ 
ture and productivity (Lamberti et 
ah, 2010). The resulting decrease in 
adult returns to freshwater systems 
may, therefore, decrease the supply 
of nutrients to these systems. 
Anadromous populations of sea 
lamprey, (Petromyzon marinus ) sub¬ 
sidize Atlantic coastal freshwater 
systems during the spring with 
pulses of marine-derived nutrients 
(Nislow and Kynard, 2009; Weaver 
et ah, 2015). Sea lamprey spend 1-2 
years in the ocean as a top parasitic 
predator of marine vertebrates (Sil¬ 
va et ah, 2014) before migrating into 
temperate Atlantic coastal freshwa¬ 
ter rivers and streams. There they 
mature, construct nests, spawn, and 
subsequently die (Beamish, 1980). 
Their carcasses release marine nu¬ 
trients to the freshwater environ¬ 
ment. During summer, rising water 
temperatures and increased pho- 
