Food and initial size influence overwinter survival and condition of a juvenile marine fish (age-0 Atlantic cod)

In subarctic Newfoundland, age-0 Atlantic cod (Gadus morhua) settle into coastal habitats in several summer–autumn pulses, resulting in broad length-frequency distributions before winter. Low winter temperatures and potential decreases in food availability pose challenges for young-of-year fish. To examine how size variation affects overwintering success under contrasting food scenarios, we conducted 114-day laboratory feeding trials at ambient overwinter sea temperatures, using demersal age-0 cod collected from Newman Sound, Newfoundland. We reared two size classes of juvenile cod under four daily ration levels (starvation, low, medium, high). We used Fulton’s K condition factor to interpret effects of food availability and fish size on survival over winter. We showed that small amounts of consumed food (<1% BW·day−1) maximized winter growth and condition potential of juvenile cod in Newfoundland waters. With no food, survival of small cod dropped below 80% on Day 47, whereas survival of large juveniles remained >80% until Day 74. Therefore, we expect higher survival of earlier settlers and increased size-selective mortality in age-0 cod during either unproductive or protracted winters, when food abundance is often low.

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Allometric growth and condition factor of Atlantic cod (Gadus morhua) fed to satiation: effects of temperature and body weight

Journal of Applied Ichthyology ◽

10.1111/j.1439-0426.2009.01259.x ◽

2009 ◽

Vol 25 (4) ◽

pp. 401-406 ◽

Cited By ~ 9

Author(s):

T. Árnason ◽

B. Björnsson ◽

A. Steinarsson

Keyword(s):

Body Weight ◽

Gadus Morhua ◽

Condition Factor ◽

Atlantic Cod ◽

Allometric Growth ◽

Effects Of Temperature

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An individual-based analysis of the variability of eggs and their newly hatched larvae of Atlantic cod (Gadus morhua) on the Scotian Shelf

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-106 ◽

1995 ◽

Vol 52 (5) ◽

pp. 1083-1093 ◽

Cited By ~ 28

Author(s):

Thomas J. Miller ◽

Tomasz Herra ◽

William C. Leggett

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Seasonal Pattern ◽

Size Variation ◽

Seasonal Temperature ◽

Scotian Shelf ◽

Larval Size ◽

Newly Hatched Larvae ◽

Shelf Region ◽

Egg Diameter

We assessed the seasonal pattern of size variation in cod eggs on the Scotian Shelf region of the Northwest Atlantic during the period March 1991–May 1993. Cod eggs were present from October to May during the surveys. Spawning was not strongly bimodal. There was a dominant autumn peak, in contrast to the historically dominant spring spawning. Egg diameter varied seasonally. Seasonal temperature patterns explained 52% of the variation in egg diameter. By incubating the eggs on-board ship, we also assessed the seasonality of the standard length (SL) of larvae that hatched from these eggs. Larval SL also varied seasonally. Egg diameter and SL were significantly correlated, but the correlation was weak (r2 = 0.3). However, the strength of correlation was consistent with laboratory estimates based on individual data. The results suggest that previous estimates of the egg size – larval size correlations are inflated. Temperature exerted a significant effect on both egg diameter and larval size, and is hypothesized to be the agent responsible for the observed seasonal variation.

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An eighteenth century commercial length-frequency sample of Atlantic cod, Gadus morhua, based on archaeological data

Fisheries Research ◽

10.1016/0165-7836(93)90161-y ◽

1993 ◽

Vol 18 (3-4) ◽

pp. 335-347 ◽

Cited By ~ 3

Author(s):

T.J. Kenchington ◽

E.L.R. Kenchington

Keyword(s):

Eighteenth Century ◽

Gadus Morhua ◽

Atlantic Cod ◽

Length Frequency ◽

Archaeological Data

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Quality of Nephrops as food for Atlantic cod (Gadus morhua L.) with possible implications for fisheries management

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.06.017 ◽

2004 ◽

Vol 61 (6) ◽

pp. 983-991 ◽

Cited By ~ 5

Author(s):

Björn Björnsson ◽

Maria Álvaro Dongala Dombaxe

Keyword(s):

Growth Rate ◽

Gadus Morhua ◽

Specific Growth ◽

Condition Factor ◽

Atlantic Cod ◽

Gonadosomatic Index ◽

Conversion Ratio ◽

Food Conversion ◽

The Mean

Abstract Nephrops was found to be of low quality as food for cod. In a laboratory experiment the mean specific growth rate of 1 kg cod was 0.184 and 0.415% d−1 when fed to satiation on Nephrops and capelin, respectively. This large difference in growth rate resulted not only from less intake of Nephrops (1.19 kg cod−1) than capelin (1.55 kg cod−1) but also because more Nephrops (4.6 kg) than capelin (2.2 kg) were required to produce each kilogramme of cod. Higher food conversion ratio was consistent with lower fat content of Nephrops (1.3%) than capelin (9.2%) but the exoskeleton also reduced the digestion rate of Nephrops. In the groups where Nephrops and capelin of equal mean weight were offered simultaneously, 40% of the diet consisted of Nephrops during the first week and 10% during the final seven weeks of the experiment. At the end of the experiment, condition factor, liver index, and gonadosomatic index were significantly lower for cod fed on Nephrops (0.967, 5.7, 7.1, respectively) than for those fed on capelin (1.086, 15.8, 11.2, respectively). These results suggests that predation by cod on Nephrops might be reduced by regular release of capelin or other similar food in the distributional areas of Nephrops.

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Abundance, seasonality and size of Atlantic salmon smolts entrained on power station intake screens in the Severn Estuary

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400047640 ◽

1994 ◽

Vol 74 (3) ◽

pp. 527-534 ◽

Cited By ~ 1

Author(s):

P.N. Claridge ◽

I.C. Potter

Keyword(s):

Atlantic Salmon ◽

Standard Length ◽

Condition Factor ◽

Early Summer ◽

Length Frequency ◽

Power Station ◽

Severn Estuary ◽

Frequency Distributions ◽

The Mean ◽

One Year

Atlantic salmon smolts were sampled from the intake screens of the Oldbury power station in the inner Severn Estuary at weekly intervals between July 1972 and June 1977. These catches, and those taken over nearly three years from the nearby Berkeley power station, demonstrated that the abundance of smolts in the estuary peaked in autumn (October) and, to a far greater extent, in spring (April and May). However, small numbers of smolts were occasionally found in all other months of the year except July. Standard length-frequency distributions of smolts remained unimodal throughout the year. Lengths ranged from 76 to 187 mm, mean 130·2 ±1·87 mm (95% CL), and wet weights ranged from 5·4 to 68·0 g, mean 26·9 ±1·17 g. The mean monthly standard length of smolts increased slightly between the autumn of one year and the spring/early summer of the next year, suggesting that, on average, the former were six months younger than the latter. The condition factor was significantly greater in autumn (1·40) than in spring (1·23). It is estimated that the total number of salmon smolts entrained annually on the screens at Oldbury during the five years ranged from 92 to 791, with a mean of 405. Total estimated numbers at Berkeley ranged from 196 to 788 per annum. The numbers at Oldbury are lower than those estimated for the downstream migrants of the Twaite shad, another anadromous species, and far lower than those of the most abundant of the marine fish species that use the Severn Estuary as a nursery area.

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Sperm competition and fertilization success in Atlantic cod (Gadus morhua): effect of sire size and condition factor on gamete quality

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-164 ◽

1999 ◽

Vol 56 (12) ◽

pp. 2315-2323 ◽

Cited By ~ 53

Author(s):

Ana Rakitin ◽

Moira M Ferguson ◽

Edward A Trippel

Keyword(s):

Body Size ◽

Sperm Competition ◽

Gadus Morhua ◽

Condition Factor ◽

Atlantic Cod ◽

Sperm Quality ◽

Fertilization Success ◽

Male Body ◽

Single Female ◽

Male Condition

Sperm competition experiments were conducted to test the null hypothesis that sperm quality is not affected by male body size in Atlantic cod (Gadus morhua). Genetic markers (allozymes) were used to determine the proportion of larvae sired by pairs of males when their sperm was combined with eggs of a single female simultaneously. Significant differences in fertilization success between males were not explained by differences in body size. Fertilization success was positively associated with male condition factor (K) and with spermatozoa density in each male's semen when equal volumes of semen from each male were used. Male K was positively associated with male fertilization success when the volume of semen used from each male was adjusted to add approximately equal numbers of spermatozoa from each male. The relative fertilization success of males varied depending on which female was the egg donor, suggesting that female "choice" at the gamete level may be occurring in cod.

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Relationships between fish and otolith dimensions of Pomatomus saltatrix (Linnaeus, 1766) (Perciformes: Pomatomidae) in southeastern Brazil

Neotropical Ichthyology ◽

10.1590/1982-0224-20180032 ◽

2019 ◽

Vol 17 (1) ◽

Cited By ~ 2

Author(s):

Geysa M. de Souza ◽

Rafael de A. Tubino ◽

Cassiano Monteiro-Neto ◽

Marcus R. da Costa

Keyword(s):

Food Habits ◽

Condition Factor ◽

Specific Model ◽

Southeastern Brazil ◽

Length Frequency ◽

Pomatomus Saltatrix ◽

Relative Growth ◽

Frequency Distributions ◽

Growth Constants ◽

Species Specific

ABSTRACT The bluefish, Pomatomus saltatrix (Linnaeus, 1766), was used as a species-specific model to study morphometric relationships between otolith size and relative growth variables. Length-weight relationships between Otolith (Length-OL, Height-OH, and Weight-OW) and fish measurements (Total Length-TL and Total Weight-TW) were determined for fishes captured monthly during the year 2015 off the southeastern coast of Brazil. The ANCOVA and Kruskal-Wallis analysis did not indicate significant differences in the relative growth constants between sexes and length frequency distributions (p > 0.05). The condition factor also did not present significant differences between sexes, and right and left otolith measurements (p > 0.05). A total of 398 specimens were sampled: TL = 43.6-67.0 cm, TW = 365-2400 g, OL = 9.65-15.25 mm, OH = 3.65 - 5.45 mm and OW = 0.03-0.11 g. The LWR for grouped sexes was TW = 0.050TL2.55 and otoliths OW = 6.17E-05OL2.59. The best adjustments were TL vs OL (r2 = 0.90); OL vs OW (r2 = 0.90); TW vs OW (r2 = 0.81); and TW vs OL (r2 = 0.80). These results showed that such relationships are helpful tools for predicting the fish size and weight from otoliths, which may be used in food habits and paleontology studies, and other fisheries management applications.

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Some Aspects of the Growth Features and Condition Factor of Arius Gigas (Boulenger, 1911) from Obuama Creek (Rivers State, Nigeria)

Transylvanian Review of Systematical and Ecological Research ◽

10.2478/trser-2021-0015 ◽

2021 ◽

Vol 23 (2) ◽

pp. 63-74

Author(s):

Olaniyi Alaba Olopade ◽

Henry Eyina Dienye ◽

Esther Ifeyinwa Nwosu

Keyword(s):

Condition Factor ◽

Management Strategies ◽

Mean Value ◽

Basic Information ◽

Allometric Growth ◽

Length Frequency ◽

Frequency Distributions ◽

Biological Features ◽

Rivers State ◽

Growth Features

Abstract Length-frequency distributions, length-weight relationships, length-length relationships and condition factors (Fulton’s KF, allometric KA, and relative KR) of Arius gigas in the Obuama Creek in Rivers State, Nigeria were investigated. 217 samples were collected from artisanal fishermen fishing on the Obuama Creek from March to September 2019. The parameter b of the length-weight relationship was 2.52 indicating negative allometric growth. The KF ranged from 0.51 to 2.03 with a mean value of 0.85 ± 0 while the overall low values of KR and KA, in this study are generally a characteristic of fish in poor health. This study provides basic information on some of the biological features of A. gigas which should be useful for facilitating management strategies and regulations of the stocks.

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Pathogenesis of Trypanosoma murmanensis in marine fish of the northwestern Atlantic following experimental transmission

Canadian Journal of Zoology ◽

10.1139/z85-315 ◽

1985 ◽

Vol 63 (9) ◽

pp. 2141-2144 ◽

Cited By ~ 19

Author(s):

R. A. Khan

Keyword(s):

Marine Fish ◽

Gadus Morhua ◽

Condition Factor ◽

Atlantic Cod ◽

Infected Fish ◽

Pathological Feature ◽

Pseudopleuronectes Americanus ◽

Potential Pathogen ◽

Myoxocephalus Scorpius ◽

Hemopoietic System

The susceptibility of four species of marine fish (Gadus morhua, Pseudopleuronectes americanus, Myoxocephalus scorpius, and Myoxocephalus octodecemspinosus) to leech-transmitted Trypanosoma murmanensis was assessed 49–60 days after infection by comparing condition factor, organ somatic indices, parasitological, hematological, and histological findings with corresponding uninfected animals. The fish were maintained at temperatures (0–1 °C) to simulate the environment where transmission occurs naturally. High mortality occurred in juvenile Atlantic cod and winter flounder, but deaths decreased with increasing fish size. No adult fish died except flounder when fin rot was present. Anemia was the most common pathological feature observed in young fish at necropsy, but its severity was not always correlated with the level of parasitemia. The persistent anemia was probably associated with an inactive rather than an impaired hemopoietic system. Condition factor and somatic indices of liver, spleen, and heart were altered in some infected fish groups. It is concluded that T. murmanensis is a potential pathogen, especially to juvenile American plaice, Hippoglossoides platessoides, in which high prevalences of natural infections have been observed in some areas of the northwestern Atlantic Ocean.

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