scholarly journals Spatial and seasonal variation in reproductive characteristics and spawning of southern calamary (Sepioteuthis australis): spreading the mortality risk

2004 ◽  
Vol 61 (6) ◽  
pp. 921-927 ◽  
Author(s):  
Natalie A. Moltschaniwskyj ◽  
Michael A. Steer
Keyword(s):  
Reproductive Output ◽  
East Coast ◽  
Biological Significance ◽  
Egg Masses ◽  
Spawning Aggregations ◽  
Southeast Coast ◽  
Spatial And Seasonal Variation ◽  
Risk Of Mortality ◽  
Spawning Behaviour ◽  
Oyster Bay

Abstract Southern calamary (Sepioteuthis australis) in Tasmania form spawning aggregations in Great Oyster Bay on the central east coast of Tasmania during spring/summer; these are targeted by commercial fishers. However, it is not known if there are similar aggregations farther south in Tasmania or at other times of the year, mainly because the species lives for less than a year. Therefore, this study describes and identifies differences in reproductive ecology of southern calamary on the east and southeast coasts of Tasmania, by sampling adults and surveying egg masses at inshore sites in both regions. Inshore populations on both coasts showed a similar seasonal trend of large gonosomatic index, reproductive output, and body size, and of greatest abundance during spring, and lowest in autumn. The number of egg masses was higher on the east coast, where mature calamary formed large spawning aggregations during spring and summer. However, there were no such aggregations during winter or autumn. Along the southeast coast, spawning activity was sporadic, resulting in isolated, low density, egg patches deposited over broader areas during spring, summer, and winter. There was no evidence of areas of seagrass or macroalgae associated with large depositions of egg masses at any time on the southeast coast. It appears that, by adopting different spawning behaviour in different locations and seasons, southern calamary may spread the risk of mortality in both space and time. The biological significance of this is unclear, particularly with respect to understanding the mechanisms that drive the development of spawning aggregations. Both spatial and seasonal spawning patterns appear to result from specific use of inshore sites at certain times of the year.

Additional Evidence Supporting Demic Behaviour of a Yellow Perch (Perca flavescens) Population

1990 ◽  
Vol 47 (10) ◽  
pp. 1959-1962 ◽  
Author(s):  
S. K. Aalto ◽  
G. E. (Buck) Newsome
Keyword(s):  
Yellow Perch ◽  
Perca Flavescens ◽  
Egg Masses ◽  
Spawning Site ◽  
Spawning Behaviour ◽  
Additional Support

To test the hypothesis that yellow perch (Perca flavescens) return to their natal location to spawn, the following experimental manipulations were performed. During the years 1978 through 1989, the egg-masses deposited by females along isobathic transects at a number of sites in Lochaber Lake were counted. During the years 1984 through 1987, egg-masses were removed from one of the sites in the lake during the spawning seasons. There was a statistically significant reduction in the proportion of egg-masses deposited within the boundaries of the site from which the egg-masses were removed. The analysis strongly suggests that the model of perch spawning behaviour which assumes that any perch selects a spawning site independently of its natal site may be rejected. This result provides additional support for the hypothesis that yellow perch exhibit demic behaviour.

scholarly journals An investigation of the spawning behaviour of the chokka squid Loligo reynaudii and the potential effects of temperature using acoustic telemetry

2009 ◽  
Vol 67 (2) ◽  
pp. 231-243 ◽  
Author(s):  
Nicola J. Downey ◽  
Michael J. Roberts ◽  
Dan Baird
Keyword(s):  
Acoustic Telemetry ◽  
Environmental Variability ◽  
Spawning Site ◽  
Spawning Aggregations ◽  
Spawning Behaviour ◽  
Effects Of Temperature ◽  
Continuous Presence ◽  
Receiver Arrays ◽  
Spawning Sites

Abstract Downey, N. J., Roberts, M. J., and Baird, D. 2010. An investigation of the spawning behaviour of the chokka squid Loligo reynaudii and the potential effects of temperature using acoustic telemetry. – ICES Journal of Marine Science, 67: 231–243. Spawning aggregations of chokka squid are influenced by environmental conditions. Acoustic telemetry was used to monitor the behaviour of spawning squid in relation to environmental variability. During the November squid-fishery closed seasons of 2003–2006, hexagonal VR2 receiver arrays were moored on and around active spawning aggregations in Kromme Bay, South Africa. In all, 45 squid were tagged (V9P-6L-S256 transmitters) and released within these arrays. Three presence–absence behaviours were identified: (i) arrival on the spawning site at dawn and departure after dusk, (ii) continuous presence for a number of days, and (iii) presence interrupted by frequent but short periods of absence. Movement between spawning sites was both diurnal and nocturnal. Squid presence at the monitored sites increased after dawn and decreased towards and after dusk. Occasionally, a core aggregation of squid remained on the spawning sites at night. Temperature data at the sites indicated occasional upwelling, and although the role of temperature in the spawning process is not well understood, data suggest that it is linked to the continuation and or interruption of spawning after an aggregation has formed. The initial formation of spawning aggregations appears to be triggered by upwelling events.

scholarly journals Multiple mating in the traumatically inseminating Warehouse pirate bug, Xylocoris flavipes : effects on fecundity and longevity

2012 ◽  
Vol 8 (5) ◽  
pp. 706-709 ◽  
Author(s):  
Amy Backhouse ◽  
Steven M. Sait ◽  
Tom C. Cameron
Keyword(s):  
Reproductive Output ◽  
Multiple Mating ◽  
Indirect Costs ◽  
Lifetime Reproductive Success ◽  
Adult Longevity ◽  
Egg Viability ◽  
Female Fecundity ◽  
Risk Of Mortality ◽  
Increased Risk ◽  
Population Consequences

Optimal mating frequencies differ between sexes as a consequence of the sexual differentiation of reproductive costs per mating, where mating is normally more costly to females than males. In mating systems where sexual reproduction is costly to females, sexual conflict may cause both direct (i.e. by reducing female fecundity or causing mortality) and indirect (i.e. increased risk of mortality, reduced offspring viability) reductions in lifetime reproductive success of females, which have individual and population consequences. We investigated the direct and indirect costs of multiple mating in a traumatically inseminating (TI) predatory Warehouse pirate bug, Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae), where the male penetrates the female's abdomen during copulation. This study aimed to quantify the effects of TI on female fecundity, egg viability, the lifetime fecundity schedule, longevity and prey consumption in this cosmopolitan biocontrol agent. We found no difference in the total reproductive output between mating treatments in terms of total eggs laid or offspring viability, but there were significant differences found in daily fecundity schedules and adult longevity. In terms of lifetime reproduction, female Warehouse pirate bugs appear to be adapted to compensate for the costs of TI mating to their longevity.

Dualistic spawning behaviour of the cunner, Tautogolabrus adspersus (Pisces: Labridae), in Bonne Bay, Newfoundland

1981 ◽  
Vol 59 (8) ◽  
pp. 1582-1585 ◽  
Author(s):  
Robert A. Pottle ◽  
John M. Green ◽  
Guy Martel
Keyword(s):  
Tautogolabrus Adspersus ◽  
Spawning Aggregations ◽  
Single Location ◽  
Group Spawning ◽  
Spawning Behaviour ◽  
Blue Phase ◽  
Recorded Occurrence

Group spawning and pair spawning cunners, Tautogolabrus adspersus, were studied at Bonne Bay, Newfoundland. This is the first recorded occurrence of both types of spawning behaviour of this species at a single location. Group spawning occurred within aggregations of 30 to > 150 fish. Cunners in group spawning aggregations ranged in length from 80 to 180 mm. Those with brown phase colouration outnumbered those with male nuptial (blue phase) colouration by at least 3:1. All courtship was initiated by males with nuptial colouration, but some brown-phase males participated in group spawnings. Pair spawning involved territorial males and was observed within 5 m of an aggregation in which group spawning was occurring. Territorial males were larger than 200 mm and had nuptial colouration. They were not observed where small (< 180 mm) cunners were most abundant. Group spawning occurred in the afternoon, being most frequent between 1800 and 1900 hours.

Physiological characteristics of crab Portunus sanguinolentus egg mass extract from southeast coast of India

2014 ◽  
Vol 0 (0) ◽  
Author(s):  
Subramanian Bragadeeswaran ◽  
Nadarajah Sri Kumaran ◽  
Lakshmanan Pandimuthu ◽  
Rajagopal Prabahar
Keyword(s):  
Physiological Characteristics ◽  
Egg Mass ◽  
Cytotoxic Activities ◽  
Egg Masses ◽  
Southeast Coast Of India ◽  
Standard Methods ◽  
Southeast Coast ◽  
Antimicrobial Assay

AbstractThe present investigation was undertaken to evaluate the physiological characteristics of crab egg mass (Assays were followed by standard methods.A maximum of 256 hemolytic units (HU) and a minimum of 128 HU were found in chicken and goat erythrocytes. In an antimicrobial assay,The results indicate that crab egg masses have remarkable antimicrobial, hemolytic and cytotoxic activities.

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