Diet and reproduction in the white-spotted eagle ray Aetobatus narinari from Queensland, Australia and the Penghu Islands, Taiwan

2010 ◽  
Vol 61 (11) ◽  
pp. 1278 ◽  
Author(s):  
V. Schluessel ◽  
M. B. Bennett ◽  
S. P. Collin
Keyword(s):  
Biological Data ◽  
Hermit Crabs ◽  
Group Index ◽  
Ductus Deferens ◽  
Important Prey ◽  
Disc Width ◽  
Dietary Shifts ◽  
Spotted Eagle Ray ◽  
Penghu Islands ◽  
Management And Conservation

Aetobatus narinari, a circumglobal batoid, is subjected to increasing fishing pressures, especially throughout South-east Asia. However, its management and protection is complicated by the lack of relevant life history information. It appears to be a late-maturing, long-lived stingray with a size-at-maturity of ∼130 and >150 cm in ventral disc width for males and females respectively. Like other myliobatids, A. narinari is a matrotrophic viviparous species exhibiting lipid histotrophy as indicated by trophonemata. Only the left ovary and uterus are functional. The presence of mature sperm in the testes, collecting ducts, epididymis and ductus deferens coincided with the estimated time of parturition and mating. Catches indicated an unbiased sex ratio. Aetobatus narinari is a hard-prey specialist that feeds mainly on gastropods, molluscs and hermit crabs (Diogenidae). Molluscs comprised numerically and gravimetrically the most important prey group (Index of Relative Importance (IRI): 85.9% in Australia, 99.9% in Taiwan) and were observed in 83.3% and 100% of stomachs containing food from Australia and Taiwan respectively. Minor dietary shifts from a gastropod–crustacean to a more gastropod–bivalve based diet occurred as body size increased. This study provides vital biological data for the effective management and conservation of A. narinari.

Comparison between the feeding habits of spotted eagle ray (Aetobatus narinari) and their potential prey in the southern Gulf of Mexico

2018 ◽  
Vol 99 (3) ◽  
pp. 661-672 ◽  
Author(s):  
F. Serrano-Flores ◽  
J.C. Pérez-Jiménez ◽  
I. Méndez-Loeza ◽  
K. Bassos-Hull ◽  
M.J. Ajemian
Keyword(s):  
Gulf Of Mexico ◽  
Prey Species ◽  
Prey Availability ◽  
Feeding Habits ◽  
Small Scale ◽  
Potential Prey ◽  
Important Prey ◽  
Ecological Aspects ◽  
Southern Gulf Of Mexico ◽  
Spotted Eagle Ray

In the southern Gulf of Mexico, the spotted eagle ray (Aetobatus narinari) is the second most frequently caught batoid in small-scale fisheries off Campeche. Ecological aspects of this ray are unknown in this region, hampering the understanding of the relationship between its distribution and prey availability in the fishing area. In order to study the feeding habits of this batoid and characterize its potential prey in the study area, stomachs and intestines of 154 specimens (68 females and 86 males) were analysed. The results indicated that A. narinari near Campeche is a specialist and selective predator that feeds mainly on gastropods (92.7% IRI), with no significant differences in the diet found between sexes, size groups, or between stomach and intestine contents. In addition, the results indicated that the most important prey species in the diet were among the most common benthic species in three of the four sampling transects positioned in or adjacent to fishing areas for rays. These most important prey species were Strombus pugilis (53.33% IRI) and Americoliva reticularis (25.6% IRI). Other prey species included Lobatus costatus (5.6% IRI) and Petrochirus diogenes (3.6% IRI). This study suggests that this widely distributed ray species feeds in Campeche's coastal waters and that the study of its potential prey increases the understanding of ecological aspects of the species, which emphasizes the added importance of monitoring fishery impacts on prey species (e.g. the conch fishery off Campeche) to help support integrated assessment and management of fisheries.

scholarly journals Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature

2012 ◽  
Vol 69 (10) ◽  
pp. 1812-1822 ◽  
Author(s):  
Sophy R. McCully ◽  
Finlay Scott ◽  
Jim R. Ellis
Keyword(s):  
Temporal Changes ◽  
Biological Data ◽  
Marine Science ◽  
British Isles ◽  
Conversion Factors ◽  
Total Length ◽  
Disc Width ◽  
Spatial Differences ◽  
First Maturity ◽  
The Relationship

Abstract McCully, S. R., Scott, F., and Ellis, J. R. 2012. Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature. –ICES Journal of Marine Science, 69: 1812–1822. Biological data on skates (Rajidae) from around the British Isles were collected between 1992 and 2010. The relationship between total length and weight for nine species (Amblyraja radiata, Dipturus batis-complex, Leucoraja fullonica, L. naevus, Raja brachyura, R. clavata, R. microocellata, R. montagui, and R. undulata) are provided for each sex and ICES ecoregion (when significantly different). Conversion factors for disc width to total length are provided. The lengths at first maturity and of the largest immature skates are reported for each sex, and the lengths at 50% maturity are estimated. Spatial differences in the length at maturity of R. clavata (females only) and L. naevus (both sexes) were observed. The lengths at maturity are discussed in relation to the results of earlier studies, and methodological differences are considered to have influenced reputed decreases in the length at maturity. A more standardized approach to collecting and reporting maturity information is required if potential spatial differences and temporal changes are to be investigated.

scholarly journals Perceptions of the use and value of fungi by two groups of young adults from Central America

2019 ◽  
Vol 11 (3) ◽  
pp. 345-351
Author(s):  
Carlos Rojas Alvarado ◽  
Sergio Molina-Murillo ◽  
Robin G. Doss
Keyword(s):  
Young Adults ◽  
Costa Rica ◽  
Central America ◽  
Formal Education ◽  
Biological Data ◽  
Social Aspects ◽  
Ecological Processes ◽  
Conservation Of Natural Resources ◽  
The City ◽  
Management And Conservation

Introduction: Integrated efforts for the management and conservation of natural resources require the availability of socio-cultural information. However, perceptional studies are rarely used along with biological data to design methodologies of biodiversity conservation. Objective: To explore the potential of perceptional information on fungi as a tool for developing culture-sensitive methods of management and conservation. Methods: Through a survey-based design, ethnomycological information from urban settings in Honduras and Costa Rica was collected and evaluated for a group of young adults (16-25 years old, N=615 surveys). Results: Fungi were not perceived to have the value of plants and animals, in both countries. The latter were mentioned as preferred by 74% of respondents. By country, 39% of Costa Ricans mentioned the most important use of fungi to be food, whereas 58% of Hondurans responded a medicinal application. Remarkably, 27% of respondents in Costa Rica mentioned that fungi are important in ecological processes, much higher than Hondurans with only 7%. Conclusions: Exposure to formal education or previous cultural background may not play such an important role in shaping perceptions of the group of fungi as it does social aspects associated with the city lifestyle in the populations studied.

Variability in the diet of bottlenose dolphin, Tursiops truncatus, in Galician waters, north-western Spain, 1990–2005

2007 ◽  
Vol 87 (1) ◽  
pp. 231-241 ◽  
Author(s):  
M.B. Santos ◽  
R. Fernández ◽  
A. López ◽  
J.A. Martínez ◽  
G.J. Pierce
Keyword(s):  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Total Consumption ◽  
Blue Whiting ◽  
Important Prey ◽  
Spawning Stock ◽  
Dietary Shifts ◽  
Western Spain ◽  
Mature Fish ◽  
North Western

We describe the diet of bottlenose dolphins Tursiops truncatus in Galician waters, north-western Spain, based on 82 non-empty stomachs recovered and analysed from stranded animals between 1990 and 2005, quantifying interannual and seasonal variation in the diet, as well as dietary variation related to sex and size. The most important prey species (in terms of numerical importance and biomass) were blue whiting (Micromesistius poutassou) and hake (Merluccius merluccius), both of high commercial importance in Galician waters. Most blue whiting eaten by dolphins were mature fish but the estimated total consumption was relatively low (around 10%) compared to Spanish fishery landings of this species. In contrast, most hake eaten by dolphins were probably immature but the estimated total consumption is more than 20% of current annual fishery landings. The diet of by-caught animals, which made up around one third of the sample, was very similar to that in the overall sample. Although bottlenose dolphins are often seen close inshore, evidence from the diet suggests that they feed at the shelf edge. Evidence was found of ontogenetic dietary shifts and differences between diets of male and female dolphins. There were also clear changes in average diet over the 16-year study period, although there was no evidence that they were in response to changes in fish abundance. The amount of hake in the diet remained stable against a background of falling local abundance while the amount of blue whiting declined despite an increase in spawning stock size.

Kryptorchismusdiagnostik mittels MRT: Ist der Nachweis des Ductus deferens hilfreich?

2005 ◽  
Vol 177 (S 01) ◽  
Author(s):  
J Gronau ◽  
LD Berthold ◽  
M Ludwig ◽  
G Alzen
Keyword(s):  
Ductus Deferens

Ameriflux Biological Data Template for Atqasuk Site

2008 ◽  
Author(s):  
W. Oechel, ◽  
J. Verfaillie,
Keyword(s):  
Biological Data ◽  
Data Template
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