This study aims to investigate the links between body condition, temperature, and skipped spawning and post-spawning survival in capelin on the Newfoundland shelf. Capelin are a key forage fish but some females and males may survive to spawn again in subsequent years. The researcher will collect capelin during fall, winter and spring to examine proportions of repeat spawners using otolith-based reconstruction of thermal history, spawning checks, and histological analysis to determine skipped spawning and post-spawning survival. This will provide insight into how temperature influences capelin recruitment and population dynamics in light of climate change.

1. Repeat and skipped spawning in capelin (Mallotus villosus) on the eastern
Newfoundland Shelf
Capelin (Mallotus villosus) is a small, short-lived (3-6 years) forage fish species that
occurs in many northern marine food webs1
. Capelin are key prey for most top predators,
including piscivorous fish (e.g. Atlantic cod), marine birds and mammals, thereby providing an
important link between lower and higher trophic levels and mediating energy flow through
marine food webs1
. In coastal Newfoundland, capelin aggregate to spawn on beaches and in
shallow water (15-40 m). Post spawning mortality is thought to be very high because spawning
involves physical contact with the seabed, where eggs adhere and remain throughout incubation2
.
Males typically arrive at spawning sites first and remain throughout the spawning season to mate
with multiple females, whereas females deposit all their eggs at one time and then leave2, 3
, likely
resulting in sex-based differences in post-spawning survival4
. Some females may survive to
spawn again, as evidenced indirectly by otolith-based observations of a ‘spawning check’5
,
indicating previous spawning, and directly by residual eggs from the previous year in the
gonads6
. Although a lab-based study revealed that males are semelparous6
, tagged males in
spawning condition have been observed in subsequent years7
, which suggests that males either
survived to spawn again or skipped spawning, possibly due to extreme temperature conditions
during or prior to spawning8
. The goal of my study is to investigate links among body condition
(i.e. energy stores), temperature, and skipped spawning and post-spawning survival. Specifically,
I will test whether temperature influences body condition, skipped spawning and post-spawning
survival.
To test this hypothesis, I will combine novel techniques, including otolith-based
reconstruction of thermal history9
and spawning checks 5
with histological techniques to directly
determine skipped spawning8
and post-spawning survival10
. Capelin will be collected from the
Newfoundland shelf during fall, winter and spring aboard Fisheries and Oceans Canada research
vessels. At each sampling location, gonads will be removed and preserved in 10% buffered
formalin from 25 fish per sex and carcasses will be frozen. In the lab, total length (snout to tip of
tail, cm), total body mass (g) and gonad mass (g) will be measured and body condition, or energy
stores, will be quantified by calculating Fulton’s K (K = [(body mass (g) - gonad mass (g))/(total
length (cm)3
) x 1000]). Otoliths will be removed to determine fish age (years) by counting the
number of alternating winter (translucent) and summer (opaque) bands, with a pair of translucent
and opaque bands representing one year of growth11,12
. Otolith trace element concentrations will
be quantified throughout the lifespan of each fish using laser ablation inductively coupled plasma
mass spectrometry, with otolith concentrations of strontium and barium used as age-specific
proxies of environmental conditions (e.g., temperature, salinities) experienced12
. Finally,
histological techniques will be used to determine the presence of residual oocytes, evidence of
previous spawning10
, as well as skipped spawning8
.
Overall, the proposed study will quantify the proportion of repeat spawners and non-
reproductive male and female capelin in a given year and examine the influence of temperature.
This will provide a quantitative estimate of the effective population size of Newfoundland
capelin, thereby increasing our understanding of the influence of temperature on recruitment and
population dynamics, providing insight into the future impacts of climate change.

2. Bibliography
1
Carscadden J.E. and Vilhjalmsson H. 2002. Capelin – What are they good for? ICES Journal of
Marine Science. 59: 863 – 869.
2
Templeman W. 1948. The life history of the caplin (Mallotus villosus O. F. Muller) in
Newfoundland waters. Bulletin of the Newfoundland Government Laboratory No. 17: 1-
151.
3
Friis-Rodel E. and Kanneworff P. 2002. A review of capelin (Mallotus villosus) in Greenland
waters. ICES Journal of Marine Science. 59: 890 – 896.
4
Shackell N.L., Shelton P.A., Hoenig J.M., and Carscadden J.E. 1994. Age-spcecific and sex-
specific survival of Northern Grand Bank capelin (Mallotus villosus). Canadian Journal
of Fisheries and Aquatic Sciences. 51:642–649.
5
Winters G.H. 1971. Fecundity of the left and right ovaries of Grand Bank capelin (Mallotus
villosus). Journal Fisheries Research Board of Canada. 28(7): 1029 – 1033.
6
Burton, M.P. and Flynn S.R. 1998. Differential postspawning mortality among male and female
capelin (Mallotus villosus Müller) in captivity. Canadian Journal of Zoology. 76: 588 –
592.
7
Nakashima B.S. 1992. Patterns in coastal migration and stock structure of capelin (Mallotus
villosus). Canadian Journal of Fisherires and Aquatic Science. 49: 2423 – 2429.
8
Rideout R.M., Rose G.A., and Burton M.P. 2005. Skipped Spawning in female iteroparous
fishes. Fish and Fisheries. 6: 50 – 72.
9
Campana S.E. 1999. Chemistry and composition of fish otoliths: pathways, mechanisms and
applications. Marine Ecology Progress Series. 188:263 – 297.
10
Flynn S.R., Nakashima B.S., and Burton M.P. 2001. Direct assessment of post-spawning
survival of female capelin, Mallotus villosus. Journal of the Marine Biological
Association of the United Kingdom. 81: 307 – 312.
11
Hedeholm, R., Grønkjær, P., Rosing-Asvid, A., and Rysgaard, S. 2010. Variation in size and
growth of West Greenland capelin (Mallotus villosus) along latitudinal gradients. ICES
Journal of Marine Science. 67: 1128 - 1137.
12
Davoren, G. K., and Halden, N. M. 2014. Connectivity of capelin (Mallotus billosus) between
regions and spawning habitats in Newfoundland inferred from otolith chemistry.
Fisheries Research. 159: 95 - 104.