نتایج جستجو برای: dasyatidae
تعداد نتایج: 156 فیلتر نتایج به سال:
Serum corticosterone was previously studied in numerous elasmobranch fishes (sharks, skates and rays), but the role of this steroid, widespread throughout many taxa, has yet to be defined. The goal of this study was to test whether corticosterone varied in response to acute and chronic capture stress, and across the reproductive cycle in the bonnethead shark, Sphyrna tiburo, and Atlantic stingr...
This study was conducted to determine the concentration of total mercury in the edible portion of 46 species of marine fish (n = 297) collected from selected major fish landing ports and wholesale markets throughout Peninsular Malaysia. Samples were collected in June to December 2009. Prior to analysis, the fish samples were processed which consisted of drying at 65 °C until a constant weight w...
An annotated checklist of chondrichthyan fishes (sharks, batoids, and chimaeras) occurring in Taiwanese waters is presented. The checklist is the result of a biodiversity workshop held in Mach 2012 as well as on-going systematic revisions by the authors. The chondrichthyan fauna of Taiwan is one of the richest in the world with the number of species totaling 181, comprising 52 families and 98 g...
This study characterizes the seasonal reproductive cycle of female round stingrays (Urobatis halleri) in an open coastal site at Seal Beach, CA and a protected estuary at the Seal Beach National Wildlife Refuge (SBNWR). Female round stingrays were sampled from August 2004 to July 2006, and assessed for reproductive parameters (GSI, maximum ova diameter, pregnancy status) and sex steroid (estrad...
Animals can perceive tourists as predators and will incur fitness costs should their predator-avoidance behaviours result in forgone resource acquisition. Not all wildlife, however, treat tourists as predators; animals can respond positively to tourists, especially when food is used as an attractant. We investigate the costs posed by novel grouping over a tourism-provisioned food resource in a ...
INTRODUCTION Accidents caused by fish are common in inland fishing communities in Brazil, being work-related injuries in the majority of cases. These populations have no information on the mechanisms of trauma or envenoming. METHODS Through a questionnaire administered to fishermen, we obtained clinical and epidemiological data on accidents in Rosana, Pontal do Paranapanema, State of São Paul...
Marine elasmobranchs maintain internal osmolality higher than their external environment, resulting in an osmotic gradient for branchial water uptake. This gradient is markedly increased in low-salinity habitats. The subsequent increase in water uptake presents a challenge to volume homeostasis. The Atlantic stingray is a marine elasmobranch that inhabits a remarkable range of environmental sal...
© 2008 International Society of Travel Medicine, 1195-1982 Journal of Travel Medicine, Volume 15, Issue 2, 2008, 102–109 A sharks may attack man without warning, stingrays are docile, usually nonaggressive, and do not attack man unless disturbed, by coastal waders or divers or caught or netted by fi shermen. Because stingrays are ubiquitous in all temperate and tropical oceans worldwide, and ev...
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