Experimental Studies of the Reproductive Behaviour of the Parasitic Copepod Lernaeocera Branchialis (Pennellidae)

1989 ◽  
Vol 69 (2) ◽  
pp. 465-476 ◽  
Author(s):  
Morten Anstensrud
Keyword(s):  
Gadus Morhua ◽  
Experimental Studies ◽  
Reproductive Behaviour ◽  
Parasitic Copepod ◽  
Infective Stage ◽  
Free Swimming ◽  
Frontal Filament ◽  
Gill Cavity ◽  
Merlangius Merlangus ◽  
Early Larval Development

Egg-producing Lernaeocera branchialis (L.) are usually found in the gill cavity of cod (Gadus morhua (L.)) and whiting (Merlangius merlangus (L.)) (Kabata, 1979). The early larval development of the copepod includes two free-swimming nauplius stages followed by the first infective stage, the copepodite (Sproston, 1942). On an intermediate host, usually flounder (Platichthys flesus (L.)), the copepodite moults into a chalimus larva which is attached by its frontal filament to the gill tips of its host. After four successive chalimus stages, the parasite reaches maturity and copulation occurs on the flatfish host.

scholarly journals Role of kairomones in host location of the pennellid copepod parasite, Lernaeocera branchialis (L. 1767)

Parasitology ◽  
2013 ◽  
Vol 140 (6) ◽  
pp. 756-770 ◽  
Author(s):  
A. J. BROOKER ◽  
A. P. SHINN ◽  
S. SOUISSI ◽  
J. E. BRON
Keyword(s):  
Life Cycle ◽  
Adult Female ◽  
Gadus Morhua ◽  
Host Location ◽  
Parasitic Copepod ◽  
Homogeneous Population ◽  
Host Seeking ◽  
Merlangius Merlangus ◽  
Genetically Determined

SUMMARYThe life cycle of the parasitic copepod Lernaeocera branchialis involves 2 hosts, typically a pleuronectiform host upon which development of larvae and mating of adults occurs and a subsequent gadoid host, upon which the adult female feeds and reproduces. Both the copepodid and adult female stages must therefore locate and identify a suitable host to continue the life cycle. Several mechanisms are potentially involved in locating a host and ensuring its suitability for infection. These may include mechano-reception to detect host movement and chemo-reception to recognize host-associated chemical cues, or kairomones. The aim of this study was to identify the role of kairomones in host location by adult L. branchialis, by analysing their behaviour in response to fish-derived chemicals. Experiments demonstrated that water conditioned by immersion of whiting, Merlangius merlangus, elicited host-seeking behaviour in L. branchialis, whereas cod- (Gadus morhua) conditioned water did not. Lernaeocera branchialis are considered a genetically homogeneous population infecting a range of gadoids. However, their differential response to whiting- and cod-derived chemicals in this study suggests that either there are genetically determined subspecies of L. branchialis or there is some form of environmental pre-conditioning that allows the parasite to preferentially recognize the host species from which it originated.

Spawning behaviour of Atlantic cod, Gadus morhua: evidence of mate competition and mate choice in a broadcast spawner

1999 ◽  
Vol 56 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Jeffrey A Hutchings ◽  
Todd D Bishop ◽  
Carolyn R McGregor-Shaw
Keyword(s):  
Mate Choice ◽  
Gadus Morhua ◽  
Dna Analysis ◽  
Atlantic Cod ◽  
Multiple Paternity ◽  
Reproductive Behaviour ◽  
Male Dominance ◽  
Male Body ◽  
Experimental Conditions ◽  
Spawning Period

We quantified individual differences in Atlantic cod, Gadus morhua, reproductive behaviour at a field-reported spawning density under experimental conditions. Marked individuals (nine females, seven males) were observed twice daily and videotaped continuously for 9 weeks at ambient photoperiod and temperature in a large tank (60 m3). Agonistic interactions appeared to maintain a size-based dominance hierarchy among males. Multiple paternity per spawning bout, revealed by microsatellite DNA analysis, suggested a link between dominance and fertilization success. Interactions between sexes were dominated by the circling of females by males. Predicated by vertical separation from males, and after descending to the bottom, a motionless female would be circled up to 17 times, often by one male per circling bout but by several males throughout the spawning period. Although circling frequency increased with male dominance and male body size, initiation and termination of this behaviour appeared to be under female control. Circling provides opportunities for males to gain individual access to reproductive females and for females to assess the quality of potential mates. Our evidence for nonrandom mate choice and for male-male competition and display has implications for Atlantic cod mating systems and effects of fishing on their reproductive success.

Cod courtship song: a song at the expense of dance?

1999 ◽  
Vol 77 (4) ◽  
pp. 542-550 ◽  
Author(s):  
Frode Engen ◽  
Ivar Folstad
Keyword(s):  
Mate Choice ◽  
Gadus Morhua ◽  
Reproductive Behaviour ◽  
Courtship Song ◽  
Sexually Dimorphic ◽  
Individual Quality ◽  
Allocation Of Resources ◽  
Parasite Resistance ◽  
Sperm Density ◽  
Tentative Explanation

Sexually selected characters may reveal information about individual quality during mate choice. Fin display and sound emitted with the aid of specific drumming muscles are characters described as being of importance in the reproductive behaviour of cod (Gadus morhua L.). We examined whether the mass of drumming muscles or fin size was sexually dimorphic, and whether these characters could provide information about male cod that was potentially of benefit to mate-seeking females. The mass of drumming muscles, but not fin size, was sexually dimorphic, with males having larger muscles than females. Neither the mass of drumming muscles nor fin size apparently revealed information about traits that may be associated with parasite resistance in males (i.e., parasite intensities and leukocyte densities). However, variation in fertilization potential (i.e., spermatocrit level) among males was related to both mass of drumming muscles and fin size. Thus, by evaluating sound and fin size, mate-seeking females may obtain information about fertilization ability among males. This may be of particular importance for females in a species whose eggs commonly remain unfertilized. Furthermore, males with large drumming muscles and small fins had low spermatocrit levels. This may reflect reductions in sperm density resulting from frequent ejaculations by attractive males. A costly allocation of resources for the development of drumming muscles at the expense of fin muscles used for propulsion is presented as a tentative explanation as to why females should pay attention to these particular traits during courtship. Increased investment in "song" may thus appear at the expense of "dance."

Seasonal and between-year variations in the diet of harbour seals in the Moray Firth, Scotland

1996 ◽  
Vol 74 (6) ◽  
pp. 1110-1121 ◽  
Author(s):  
D. J. Tollit ◽  
P. M. Thompson
Keyword(s):  
Diet Composition ◽  
Gadus Morhua ◽  
Prey Species ◽  
Temporal Variations ◽  
Short Term ◽  
Harbour Seals ◽  
Faecal Samples ◽  
Poor Indicator ◽  
Moray Firth ◽  
Merlangius Merlangus

Predictions concerning the effect of seals upon prey stocks require an understanding of temporal variations in diet composition. This study examined the extent of between-year and seasonal variations in the diet of harbour seals (Phoca vitulina) from the Moray Firth, Scotland, between 1989 and 1992. Analyses of fish otoliths and cephalopod beaks collected from 1129 faecal samples were used to derive estimates of the contribution made by each of 35 prey species, based on the number and mass consumed. The key prey, by mass, were sand eels (Ammodytidae) (47%), lesser octopus (Eledone cirrhosa) (27%), whiting (Merlangius merlangus) (6%), flounder (Platichthys flesus) (5%), and cod (Gadus morhua) (4%). Between-year and seasonal fluctuations in the contributions of these species were observed. Sand eels contributed 86–20% in summer and 91–49% in winter. Lesser octopus contributed 0–62% in summer and < 5% in winter, whilst whiting and cod contributed 2–34% in winter and 1–4% in summer. In contrast to 1988, clupeids were unimportant in winter. Differences in diet composition appeared to reflect local changes in the availability of food, especially overwintering clupeids. Results indicate that dietary information obtained from short-term studies can be a poor indicator of subsequent diet composition and should be treated with caution when used to predict the effect of seals on prey populations.

Free-living stages of the parasitic copepod Lernanthropinus labracoglossae Izawa, 2014 (Siphonostomatoida, Lernanthropidae), reared from eggs

Crustaceana ◽  
2014 ◽  
Vol 87 (14) ◽  
pp. 1691-1698 ◽  
Author(s):  
Kunihiko Izawa
Keyword(s):  
Ovigerous Female ◽  
Parasitic Copepod ◽  
Free Living ◽  
Frontal Filament

Free-living stages, comprising two naupliar stages and the infective copepodid I, of the parasitic copepod Lernanthropinus labracoglossae Izawa, 2014 are described. The larvae were reared from eggs detached from an ovigerous female, recovered from the branchial lamellae of the Japanese actinopterygian fish Labracoglossa argentiventris Peter, 1866 (Kyphosidae). The number of naupliar stages prior to copepodopid I in the Lernanthropidae is the same as in the Caligidae, Pseudohatschekidae and Trebiidae. The copepodid I of the species has a frontal filament, as do representatives of the Caligidae, Pandaridae and Trebiidae. However, this is regarded as a vestigial feature in the last two families. Copepodid I of L. labracoglossae has a 6-segmented antennule, including the naked first segment, as do the first copepodids of eudactylinid copepods.

The Copepodid of Peniculisa Shiinoi Izawa, 1965 (Copepoda, Siphonostomatoida, Pennellidae), a Single Free-Swimming Larval Stage of the Species

Crustaceana ◽  
1997 ◽  
Vol 70 (8) ◽  
pp. 911-919 ◽  
Author(s):  
Kunihiko Izawa
Keyword(s):  
Larval Stage ◽  
Egg Size ◽  
Parasitic Copepod ◽  
Free Swimming ◽  
Nauplius Stage ◽  
Puffer Fish ◽  
Copepodid Stage

AbstractThe copepodid stage of the parasitic copepod Peniculisa shiinoi Izawa, 1965 (Siphonostomatoida, Pennellidae), parasitic on the fins of a puffer fish, Canthigaster rivulatus, is described based on specimens reared from eggs. This is the only free-swimming larval stage of P. shiinoi. The copepodid is distinctly smaller than those of the known pennellids. However, the dispensability of the free-swimming nauplius stage is independent of the egg-size. The copepodid antennae of the pennellids are certainly uniramous. The setation of the rami of the copepodid legs varies among pennellids.

The parasitic copepod Lernaeocera branchialis negatively affects cardiorespiratory function in Gadus morhua

2014 ◽  
Vol 84 (5) ◽  
pp. 1599-1606 ◽  
Author(s):  
J. W. Behrens ◽  
H. Seth ◽  
M. Axelsson ◽  
K. Buchmann
Keyword(s):  
Gadus Morhua ◽  
Parasitic Copepod ◽  
Cardiorespiratory Function

scholarly journals The vertical separation of fish in the aft end of a demersal trawl

2009 ◽  
Vol 66 (4) ◽  
pp. 772-777 ◽  
Author(s):  
Ludvig Ahm Krag ◽  
René Holst ◽  
Niels Madsen
Keyword(s):  
Vertical Distribution ◽  
Gadus Morhua ◽  
Melanogrammus Aeglefinus ◽  
Multinomial Model ◽  
Vertical Separation ◽  
Commercially Important ◽  
Merlangius Merlangus ◽  
The Vertical Distribution ◽  
Haddock Melanogrammus Aeglefinus ◽  
Important Fish

Abstract Krag, L. A., Holst, R., and Madsen, N. 2009. The vertical separation of fish in the aft end of a demersal trawl. – ICES Journal of Marine Science, 66: 772–777. Two multi-compartment separator frames were used to study the vertical separation of some commercially important fish species in the aft end of a trawl, with the aim of separating cod (Gadus morhua) from other species. A non-linear multinomial model with random effects was used to analyse the data and to compare the performance of the two frames. The vertical distribution of cod in the aft end of the trawl was close to uniform, whereas haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and lemon sole (Microstomus kitt) showed more uneven distributions. The use of guiding bars in the separator frame significantly (p < 0.05) increased the catch of cod, plaice, and lemon sole in the upper compartment. The vertical separation of cod was density-dependent; high densities of fish resulted in a more uniform distribution of cod. The species separations found differ from those reported from the studies of species separation in the region of the trawl mouth.

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