Reproductive behaviour of free-ranging convict cichlids,Cichlasoma nigrofasciatum

1995 ◽  
Vol 43 (2) ◽  
pp. 121-134 ◽  
Author(s):  
Brian D. Wisenden
Keyword(s):  
Reproductive Behaviour ◽  
Cichlasoma Nigrofasciatum ◽  
Convict Cichlids ◽  
Free Ranging

Factors affecting reproductive success in free-ranging convict cichlids (Cichlasoma nigrofasciatum)

1994 ◽  
Vol 72 (12) ◽  
pp. 2177-2185 ◽  
Author(s):  
Brian D. Wisenden
Keyword(s):  
Growth Rate ◽  
Reproductive Success ◽  
Stream Habitat ◽  
Factors Affecting ◽  
Cichlasoma Nigrofasciatum ◽  
Brood Survival ◽  
Spawning Site ◽  
Convict Cichlids ◽  
Significant Difference ◽  
Free Ranging

This study examines the effect of parent size, fry growth rate, and habitat-related brood predation pressure on two measures of reproductive success (percent brood survival and fry number at independence from their parents) of free-ranging convict cichlids (Cichlasoma nigrofasciatum). Four populations in Costa Rican streams were studied, two in "pool" habitat and two in "stream" habitat. The number of fry that emerged from the spawning site (as free-swimming young) was positively correlated with female standard length (SL) for sites with a relatively wide size range of breeding females. SL of males had no effect on fry number at emergence, nor did size of either parent affect the probability of a brood reaching fry independence. Large parents reared more fry to independence than small parents in stream habitat but not in pool habitat. There was a significant difference among sites in fry number at emergence but not at independence (mean = 27 fry), suggesting a maximum number of fry that two parents can economically defend. Fry growth rate had no effect on either measure of reproductive success. Reproductive success was largely determined by the effect of habitat. Adult Cichlasoma dovii in pool habitat may have reduced mean brood survival from 47% (n = 126 broods) in stream habitat to 14.9% (n = 141 broods) in pool habitat. Predators such as juvenile C. dovii may be more effective in the dim ambient light in pool habitat, overwhelming the effect of parent size on brood defence.

Changes in Aggressive Interaction in Adjacently Territorial Convict Cichlids (Cichlasoma Nigrofasciatum): a Study of Habituation

Behaviour ◽  
1971 ◽  
Vol 40 (1-2) ◽  
pp. 43-54 ◽  
Author(s):  
Michael J. Herz ◽  
Harman V.S. Peeke ◽  
James E. Gallagher
Keyword(s):  
Ecological Niche ◽  
Prolonged Exposure ◽  
Continuous Exposure ◽  
Aggressive Interaction ◽  
Minute Exposure ◽  
Cichlasoma Nigrofasciatum ◽  
Uniform Pattern ◽  
Convict Cichlids ◽  
Stimulus Source ◽  
Exposure Conditions

AbstractPairs of male Convict Cichlids (Cichlasoma nigrofasciatum) were isolated from each other and then exposed in adjoining territories under one of two exposure conditions, either daily 20 minute exposure for 38-44 days or a massed continuous exposure for 24 or 28 hours. The incidence of biting and the duration of chin display for each fish was recorded. The duration of the chin display described a near uniform pattern of attenuation for both exposure conditions. The waning of the biting response was evident but it was more variable than the chin display. It was concluded that these behaviors both tend to habituate with repeated or constant exposure to the same stimulus source and that prolonged exposure facilitates the habituation of aggressiveness between territorial neighbors, thus promoting peace in a particular ecological niche.

Technique for Tagging Small Fish with I131 for Evaluation of Predator–Prey Relationships

1978 ◽  
Vol 35 (1) ◽  
pp. 143-145 ◽  
Author(s):  
Gerard J. FitzGerald ◽  
Miles H. A. Keenleyside
Keyword(s):  
Content Analysis ◽  
Key Words ◽  
Stomach Content ◽  
Stomach Content Analysis ◽  
Small Fish ◽  
Short Term ◽  
Predator Prey ◽  
Cichlasoma Nigrofasciatum ◽  
Quantitative Studies ◽  
Convict Cichlids

Experiments to test the feasibility of using radioactive I131 as a technique for evaluation of conspecifïc predation on fry by adult convict cichlids (Cichlasoma nigrofasciatum) are described. The technique is useful for short-term quantitative studies of predator–prey interactions where it is not possible to observe and quantify predation directly or where stomach content analysis of adults is not feasible. Key words: radioactive tagging, predator–prey interactions, Cichlasoma nigrofasciatum

The Effects of a Trade-Off Between Foraging and Brood Defense On Parental Behaviour in the Convict Cichlid Fish, Cichlasoma Nigrofasciatum

Behaviour ◽  
1992 ◽  
Vol 120 (1-2) ◽  
pp. 123-138 ◽  
Author(s):  
Robert W. Rangeley ◽  
JEAN-GUY J. Godin
Keyword(s):  
Cichlid Fish ◽  
Net Energy ◽  
Activity Levels ◽  
Parental Effort ◽  
Trade Off ◽  
Cichlasoma Nigrofasciatum ◽  
Investment Theory ◽  
Convict Cichlids ◽  
Brood Defense ◽  
Energy Gains

AbstractParental convict cichlids, Cichlasoma nigrofasciatum, responded to the presence of a potential brood predator by decreasing net energy gains (food intake decreased and energy expenditure increased) while increasing parental effort (large allocation of time to brood defense). These behaviours are important factors in the life-history trade-off between current and future reproductive investments. The allocation of energy into defense behaviours and elevated activity levels, combined with a voluntary reduction of food consumption, represent an investment in the current brood which could (in nature) reduce future reproduction. Contrary to parental investment theory predictions, consistent increases in parental effort with brood age were not evident.

Weight asymmetry and sequential assessment in convict cichlid contests

1993 ◽  
Vol 71 (3) ◽  
pp. 475-479 ◽  
Author(s):  
Marten A. Koops ◽  
James W. A. Grant
Keyword(s):  
Weight Ratio ◽  
Assessment Model ◽  
Convict Cichlid ◽  
Cichlasoma Nigrofasciatum ◽  
Convict Cichlids ◽  
Temporal Overlap

We staged contests between pairs of convict cichlids (Cichlasoma nigrofasciatum) that varied in weight ratio (larger/smaller) from 1.02 to 4.86 to test the predictions of the sequential assessment model. As predicted, contests proceeded in a consistent sequence of behaviour (lateral display, biting, mouth wrestling, and circling), the duration of contests was inversely correlated with weight ratio, and the duration of complete phases of behaviour was independent of weight ratio (a phase is complete if the contest escalates to the next behavioural phase). However, there was temporal overlap in the occurrence of different behaviour patterns and variation in the duration of contests that are not explained by the model. Nevertheless, the structure of convict cichlid contests is consistent with the logic of the sequential assessment model.

scholarly journals Implementing immunocontraception in free-ranging African elephants at Makalali Conservancy

2007 ◽  
Vol 78 (1) ◽  
Author(s):  
A.K. Delsink ◽  
J.J. Van Altena ◽  
D. Grobler ◽  
H.J. Bertschinger ◽  
J.F. Kirkpatrick ◽  
...  
Keyword(s):  
Mode Of Delivery ◽  
Cost Effective ◽  
Reproductive Behaviour ◽  
Limpopo Province ◽  
Management Tool ◽  
African Elephants ◽  
Population Growth Rates ◽  
Implementation Costs ◽  
Population Sizes ◽  
Free Ranging

The goal of programmes to provide contraception for elephants should be to formulate an approach that does not require the relocation or immobilisation of the same individual year after year, which would be long-lasting and cause minimal disruption to social and reproductive behaviour. The programmes should be simple to administer, safe and cost-effective, and must meet the objectives defined by managers in the field. An immunocontraceptive programme was initiated in a small free-roaming population of elephants at the Greater Makalali Private Game Reserve in Limpopo Province in 2000 to determine whether the porcine zona pellucida (pZP) vaccine can successfully control population sizes. Further objectives were to determine implementation costs and efficiency through a multi-faceted approach. We have demonstrated that immunocontraception meets the objectives set by managers in the field. Minimal social disruption was observed over the course of treatment, with the mode of delivery (ground or aerial vaccinations) determining the degree of stress within herds and speed of resumption of normal movement patterns. Aerial vaccinations resulted in the least disturbance, with target herds being approachable within a day. In 2005, implementation costs were R880-R1000 / elephant / year, inclusive of darts, vaccine, helicopter and veterinary assistance. Irrespective of the source or method of vaccine delivery, a non-pregnant elephant is rendered infertile from 1st vaccine administration. The sooner immunocontraception is implemented, the sooner population growth rates can be controlled. pZP contraception is a realistic alternative management tool, particularly if used as part of a long-termmanagement strategy. Mass-darting from the air eliminates the need for detailed individual histories of each elephant or for employing a person to monitor elephants. Thus, implementation of immunocontraception in larger populations is feasible and practical.

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