Diet of three commercially important shark species from Western Australian waters

2001 ◽  
Vol 52 (7) ◽  
pp. 975 ◽  
Author(s):  
Colin A. Simpfendorfer ◽  
Adrian Goodreid ◽  
Rory B. McAuley
Keyword(s):  
Stomach Contents ◽  
Shark Species ◽  
Rock Lobster ◽  
Gill Net ◽  
Wide Range ◽  
Carcharhinus Obscurus ◽  
Commercially Important ◽  
Specialized Diet ◽  
Western Australian ◽  
Benthic Prey

The diets of dusky (Carcharhinus obscurus), whiskery (Furgaleus macki) and gummy (Mustelus antarcticus) sharks from south-western Western Australia were examined by analysis of stomach contents. The majority of samples were obtained from catches of commercial gill-net fishers. Carcharhinus obscurus had a diverse diet dominated by pelagic teleosts and cephalopods. A wide range of demersal and benthic prey were also consumed, but represented only a small portion of the diet. As body size increased, importance of elasmobranchs in the diet of C. obscurus increased, while most other groups remained at similar levels. Furgaleus macki had a specialized diet, feeding almost exclusively on octopus and other cephalopods. The diet of M. antarcticus was dominated by benthic and epibenthic prey, including crabs, lobsters, tetraodontid fishes and octopus. As M. antarcticus increased in size there was an increase in the occurrence of rock lobster and a decrease in the occurrence of crabs in the diet. Differences in the diet were also noted between male and female M. antarcticus, but were confounded with differences between size classes.

Biology of two commercially important carcharhinid sharks from northern Australia

1986 ◽  
Vol 37 (6) ◽  
pp. 671 ◽  
Author(s):  
JD Stevens ◽  
PD Wiley
Keyword(s):  
Stomach Contents ◽  
Size At Maturity ◽  
Northern Australia ◽  
Gill Net ◽  
Average Litter Size ◽  
Commercially Important ◽  
Mature Fish ◽  
Reproductive Cycles ◽  
Size At Birth ◽  
Pelvic Fin

Sharks represent 78% of the total catch by weight of a Taiwanese surface gill-net fishery off northern Australia. Two carcharhinids, Carcharhrnus tilstoni (previously described as C. limbatus) and C. sorrah, together comprise 83% of this shark catch by number. C. tilstoni is distinguished from C. limbatus by differences in enzyme systems, vertebral counts, size data and pelvic fin coloration. Of the specimens of C. tilstoni and C. sorrah caught in the Arafura and Timor Seas from 1981 to 1983, 43% and 47%, respectively, were female; at birth these proportions were 46% and 50%, respectively. In both species, females tended to be relatively more abundant in catches of mature fish, except around March, when males predominated. In northern Australia, the usual size at maturity for C. tilstoni is 110 cm for males and 115 cm for females; for C. sorrah, it is 90 cm and 95 cm, respectively. Both species exhibit placental viviparity and have almost identical restricted reproductive cycles. Mating occurs in February-March, ovulation in March-April and the main parturition period is in January. The gestation period is 10 months and individual fish breed each year. The average litter size for both species is three. The size at birth is about 60 cm for C. tilstoni and 50 cm for C. sorrah. Stomach contents indicate that teleost fish are an important component of the diet of both species and there is some indication of a change in feeding depth with shark size.

Isolation, crystal structure and synthesis of arsenobetaine, a constituent of the western rock lobster, the dusky shark, and some samples of human urine

1981 ◽  
Vol 34 (4) ◽  
pp. 787 ◽  
Author(s):  
JR Cannon ◽  
JS Edmonds ◽  
KA Francesconi ◽  
CL Raston ◽  
JB Saunders ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Human Urine ◽  
Simple Synthesis ◽  
Rock Lobster ◽  
Dusky Shark ◽  
Carcharhinus Obscurus ◽  
Commercially Important ◽  
Panulirus Cygnus ◽  
Tail Muscle

Arsenobetaine has been isolated from the tail muscle of the western rock lobster (Panulirus cygnus George) and from the flesh of the dusky shark (Carcharhinus obscurus Le Sueur), both of which are commercially important seafoods. Trigonelline has also been isolated from the lobster and both arsenobetaine and trigonelline have been isolated from human urine obtained after ingestion of cooked rock lobster. The crystal structures of the monohydrates of arsenobetaine and trigonelline have been determined and a simple synthesis of arsenobetaine has been developed.

scholarly journals Diet of three shark species in the Ecuadorian Pacific, Carcharhinus falciformis, Carcharhinus limbatus and Nasolamia velox

2017 ◽  
Vol 98 (4) ◽  
pp. 927-935 ◽  
Author(s):  
Colombo Estupiñán-Montaño ◽  
Fabian Pacheco-Triviño ◽  
Luis G. Cedeño-Figueroa ◽  
Felipe Galván-Magaña ◽  
Jose F. Estupiñán-Ortiz
Keyword(s):  
Stomach Contents ◽  
Thunnus Albacares ◽  
Shark Species ◽  
Dosidicus Gigas ◽  
Katsuwonus Pelamis ◽  
Carcharhinus Limbatus ◽  
Lack Of Information ◽  
Bony Fishes ◽  
Carcharhinus Falciformis ◽  
Conservation Plans

We analysed the stomach contents of 69 silky sharks Carcharhinus falciformis, 44 blacktip sharks Carcharhinus limbatus and 24 whitenose sharks Nasolamia velox caught in the Ecuadorian Pacific from August 2003 to December 2004. Prey included bony fishes, elasmobranchs, molluscs, crustaceans and turtles, with bony fishes being the most important to the diets of all three sharks, suggesting they are piscivorous predators. Based on the index of relative importance, the C. falciformis diet includes Thunnus albacares, Thunnus sp. and Auxis thazard, as well as some squid, fish and turtles. Similarly, the C. limbatus diet was dominated by T. albacares, Exocoetus monocirrhus, A. thazard, Katsuwonus pelamis, members of the Ophichthidae family and other elasmobranchs. Meanwhile, N. velox consumed mainly Dosidicus gigas, Larimus argenteus, Cynoscion sp. and Lophiodes spilurus. There is little competition for food between these tertiary carnivores: C. limbatus prefers prey from coastal-oceanic habitats; C. falciformis consumes mostly oceanic prey and N. velox focuses on prey from coastal habitats. The lack of information on the biology of sharks in Ecuador hinders the development of appropriate management and conservation plans to protect shark resources. This study increases our knowledge and understanding of sharks in Ecuador, thus contributing to their conservation.

scholarly journals Population Genetics of the Red Rock Lobster,  Jasus edwardsii

2021 ◽  
Author(s):  
◽  
Luke Thomas
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
New Zealand ◽  
Genetic Differentiation ◽  
Microsatellite Markers ◽  
Rocky Reef ◽  
Rock Lobster ◽  
Wide Range ◽  
Jasus Edwardsii ◽  
Polymorphic Microsatellite

<p>Understanding patterns of gene flow across a species range is a vital component of an effective fisheries management strategy. The advent of highly polymorphic microsatellite markers has facilitated the detection of fine-scale patterns of genetic differentiation at levels below the resolving power of earlier techniques. This has triggered the wide-spread re-examination of population structure for a number of commercially targeted species. The aims of thesis were to re-investigate patterns of gene flow of the red rock lobster Jasus edwardsii throughout New Zealand and across the Tasman Sea using novel microsatellite markers. Jasus edwardsii is a keystone species of subtidal rocky reef system and supports lucrative export markets in both Australia and New Zealand. Eight highly polymorphic microsatellite markers were developed from 454 sequence data and screened across a Wellington south coast population to obtain basic diversity indices. All loci were polymorphic with the number of alleles per locus ranging from 6-39. Observed and expected heterozygosity ranged from 0.563-0.937 and 0.583-0.961, respectively. There were no significant deviations from Hardy-Weinberg equilibrium following standard Bonferroni corrections. The loci were used in a population analysis of J. edwardsii that spanned 10 degrees of latitude and stretched 3,500 km across the South Pacific. The analysis rejected the null-hypothesis of panmixia based on earlier mDNA analysis and revealed significant population structure (FST=0.011, RST=0.028) at a wide range of scales. Stewart Island was determined to have the highest levels of genetic differentiation of all populations sampled suggesting a high degree of reproductive isolation and self-recruitment. This study also identified high levels of asymmetric gene flow from Australia to New Zealand indicating a historical source-sink relationship between the two countries. Results from the genetic analysis were consistent with results from oceanographic dispersal models and it is likely that the genetic results reflect historical and contemporary patterns of Jasus edwardsii dispersal and recruitment throughout its range.</p>

scholarly journals Stomach Content of Tillapia zilli and Oreochromis nilocticus from Wanzun River, Lavun Local Government, Niger State Nigeria

2021 ◽  
pp. 15-20
Author(s):  
Y. M. Mohammed ◽  
M. D. Abubakar ◽  
A. M. Muhammad ◽  
A. S. Muhammad ◽  
B. L. Umar ◽  
...  
Keyword(s):  
Fish Species ◽  
Stomach Content ◽  
Stomach Contents ◽  
Empty Stomach ◽  
Plant Materials ◽  
Individual Fish ◽  
Fish Samples ◽  
Commercially Important ◽  
Fish Remains ◽  
The One

This study was conducted to investigate the stomach contents of two commercially important fish species (Tilapia zilli and Oreochromis nilocticus)  from Wanzun River, Northcentral Nigeria using frequency of occurrence and volumetric methods between January to April 2019. Fish samples were collected monthly with help of Fishermen using various fishing nets and traps. One hundred (100) individual fish of each species were collected and their stomach contents were examined. The results obtained expressed in mean percentage indicated that out of the one hundred (100) individual fish of each species examined,Twelve (12%) fish had an empty stomach contents in Tilapia zilli, and out of the 100 samples examined, Seventeen (17%) fish had an empty stomach content in Oreochromis nilocticus. The stomach contents of both Tilapia zilli and Oreochromis nilocticus consist of detritus, insects, fish remains. Algae/protozoans plant materials and molluscs. Both fish species are omnivorous feeders and occupy the same ecological niche.The study reveals the importance of algae, fish, insects and plant materials as food for fishes and they form important part in the diet of the species examined.

scholarly journals Food Habits and Diet Relationship in the Redbelly Tilapia (Tilapia zillii) and Guenther’s Mouthbrooder (Chromidotilapia guntheri) from an Abandoned Gold Mine Reservoir, Southwestern Nigeria

2018 ◽  
Vol 10 (2) ◽  
pp. 148-155
Author(s):  
Olusola Olaniyi KOMOLAFE ◽  
Timothy Olalekan AMOO ◽  
Michael Olufemi AWODIRAN
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Food Sources ◽  
Gold Mine ◽  
Southwestern Nigeria ◽  
Food Items ◽  
Tilapia Zillii ◽  
Gill Net ◽  
Food And Feeding ◽  
Index Value

The food and feeding habits of the redbelly Tilapia (Tilapia zillii) and Guenther’s mouthbrooder (Chromidotilapia guntheri) were investigated in an abandoned gold mine reservoir at Igun from June 2013 to May 2014. Using a cast net and gill-net fishing gears, 370 fish individuals were caught and their stomach contents were analysed by using the frequency of occurrence and numerical methods. Tilapia zillii comprised 53.78% (199 individuals), while Chromidotilapia guntheri covered up the remaining percentage (46.22%) which is made up of 171 individuals. Food items in the stomachs of T. zillii individuals predominantly consisted of detritus, mud and algae (77.97%), while those in C. guntheri individuals mostly consisted fish remains, detritus and algae (81.67%). T. zillii exploited more food items (23 of 27) as compared to C. guntheri (17 of 27). The Schoener’s index value for the species was 0.65. The study showed that T. zillii and C. guntheri exhibited benthopelagic exploitation and are mainly herbivorous and omnivorous respectively based on the food items observed in the stomach contents of these species. The fish species fed on related food items as confirmed by Schoener’s overlap index (0.65), suggesting that there was overlap in the dietary requirements of the two species. This index value, however, was probably not an indication of competition for food between these two species because they exploited abundant food sources.

Climate change and adaptive capacity in the Western Australian rangelands: a review of current institutional responses

2015 ◽  
Vol 37 (4) ◽  
pp. 331 ◽  
Author(s):  
Ellena Shaw ◽  
G. Bradd Witt
Keyword(s):  
Climate Change ◽  
Adaptive Capacity ◽  
Social Economic ◽  
Social Systems ◽  
Institutional Support ◽  
Sufficient Evidence ◽  
Agricultural Systems ◽  
Wide Range ◽  
Agricultural Industries ◽  
Western Australian

This research analysed contemporary publications concerning climate change adaptation in the agricultural systems of the Western Australian rangelands. The term ‘systems’ refers to the supportive economic and social systems as well as agricultural industries. The aim of the study was to evaluate how the adaptive capacity of agricultural systems is supported given the anticipated challenges of climatic changes. The conceptual framework of adaptive capacity was employed to evaluate progress towards improving adaptation and resilience. Eight key indicators of adaptive capacity formed the evaluative criteria, and were applied to a wide range of publicly available documents relevant to the Western Australian rangelands. Progress towards building adaptive capacity was also evaluated by classifying the documents as ‘aspirational’, ‘in action’ or ‘assessed’. The institutional support for adaptive capacity was found to be adequate, as there was sufficient evidence that relevant institutions were providing mechanisms for social, economic and environmental adaptation in the face of climate change. The viability of the agricultural systems of the Western Australian rangelands has been in decline for some time and, therefore, the degree to which efforts to improve adaptive capacity have been successful was difficult to assess. There were methodological limitations of this research due to the limited breadth of available data and subjectivity within the data analysis process, which may have inhibited the accuracy of the findings and recommendations. Also difficulties inherent in quantifying social, economic and environmental processes at differing geographic and temporal scales, were apparent. This raises important questions regarding the extent to which the literature is able to appropriately reflect actual adaptation within the rangelands, and the extent to which stakeholders (community, pastoralists and regional organisations) perceive that adequate institutional support is being provided.

Preliminary results of a study into the incidental mortality of sharks in Gill-nets in two Tasmanian Shark Nursery Areas

1992 ◽  
Vol 43 (1) ◽  
pp. 237 ◽  
Author(s):  
H Williams ◽  
AH Schaap
Keyword(s):  
Relative Abundance ◽  
Fishing Effort ◽  
Shark Species ◽  
Nursery Areas ◽  
Preliminary Results ◽  
Gill Net ◽  
Galeorhinus Galeus ◽  
Potential Rate ◽  
Incidental Mortality ◽  
Gill Netting

Since the early 1960s, certain sheltered bays and estuaries around Tasmania have been designated shark nursery areas, where the taking of either the school shark (Galeorhinus galeus) or the gummy shark (Mustelus antarcticus) has been prohibited. Recent assessments of Australian stocks of school and gummy sharks indicate that they are close to collapse, and the management of the fishery has come under review. With respect to shark nursery areas, concern has focused on the potential rate of incidental mortality of sharks caused by recreational gill-net fishing and poaching. In 1990, a study was begun in Frederick Henry Bay and Norfolk Bay, the largest proclaimed shark nursery areas in Tasmania, to estimate recreational net-fishing effort and incidental captures of sharks. School sharks were caught in waters deeper than 5 m; gummy sharks and dogfish were caught at all depths. The diversity and relative abundance of shark species increased with depth, whereas the diversity of teleosts decreased with depth. Most captured school and gummy sharks were between 1+ and 3+ years of age. Preliminary estimates of potential incidental mortality demonstrate that gill-netting in depths greater than 5 m may be a significant source of mortality for both species.

scholarly journals Catch assessment of artisanal marine fishing gears in Cox’s Bazar and Teknaf of Bangladesh

2016 ◽  
Vol 27 (2) ◽  
pp. 228-234
Author(s):  
SK Ghosh ◽  
MK Ahsan ◽  
MK Ahmmed ◽  
SI Ahmed ◽  
MM Hasan ◽  
...  
Keyword(s):  
Fish Species ◽  
Fishing Gear ◽  
Catch Per Unit Effort ◽  
Beach Seine ◽  
Gill Net ◽  
Fishing Gears ◽  
Dominant Fish ◽  
Commercially Important ◽  
Marine Fishing ◽  
Harpadon Nehereus

Studies were conducted on catch assessment of some artisanal marine fishing gears operated in Cox’s Bazar and Teknaf areas from April 2014 to April 2015. Sixteen types of fishing gears were identified, of which gill net, beach seine net, estuarine set bag net, marine set bag net and trammel net occupy major fishing activities. Although estuarine set bag net (ESBN) is a legally restricted fishing gear recorded the highest catch per unit effort (CPUE) (110 kg/gear/day) in July followed by marine set bag net (MSBN) (105 kg/gear/day) in Cox’s Bazar and the highest CPUE was recorded 100 kg/gear/day by ESBN in June followed by MSBN (90 kg/gear/day) in Teknaf. Out of 52 species of fishes, the major fish species abundantly caught by these gears were Poa (Otolithoides argenteus), Churi (Trichiurus haumela), Loittya (Harpadon nehereus), Ranga choukha (Lutjanus johni), Lal poa (Johnius argentatus), Olua (Coilia dussumieri), Rup chanda (Stromateus chinensis), (Stromateus argenteus) and Ilish (Tenualosa ilisha). Besides these fish species, 10 commercially important shrimp species and 3 important crab species were also recorded during the study period. The peak season of availability of most fish species was June and July while lean season was December and January. This study indicated that Otolithoides argenteus) was the dominant fish species followed by Trichiurus haumela, Harpadon nehereus and Coilia dussumieri.Progressive Agriculture 27 (2): 228-234, 2016

Fish predators of the western rock lobster (Panulirus cygnus George) in a nearshore nursery habitat

1988 ◽  
Vol 39 (3) ◽  
pp. 307 ◽  
Author(s):  
RK Howard
Keyword(s):  
Fish Species ◽  
Fish Community ◽  
Carapace Length ◽  
Nursery Habitat ◽  
Rock Lobster ◽  
Lack Of Information ◽  
Gill Net ◽  
Fish Predators ◽  
Panulirus Cygnus ◽  
A Current

Nearshore limestone reefs of Western Australia represent an important nursery habitat for juveniles of the western rock lobster (Panulirus cygnus). As part of a trophic study of the fish community associated with these reefs, fishes were examined for evidence of predation on western rock lobsters. Six fish species were found to have ingested P. cygnus. Of these, Psammaperca waigiensis (sand bass), Pelsartia humeralis (sea trumpeter), Pseudolabris parilis (brown-spotted wrasse) and Plectorhyncus flavornaculatus (gold-spotted sweetlips) were among the ten most abundant fish in gill-net collections from the study site. P. cygnus formed a significant portion of the diet of P. waigiensis, but was < 5% of the dietary volume of other species. Predation occurred at all times of the day and was concentrated on small, newly-settled P. cygnus (8-15 mm carapace length). The vulnerability of lobsters to predation appears to be strongly related to size, and the cryptic habits that are unique to newly-settled stages can be explained in terms of the risks of predation. Assessment of the proportion of mortality of P. cygnus due to predation is hampered by a current lack of information on the natural densities of both fishes and small rock lobsters. However, conservative estimates indicate that an annual removal by fish of thousands of lobsters per hectare is likely, suggesting that predation is a major factor affecting the survival of P. cygnus on nursery reefs.

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