نتایج جستجو برای: pelagic
تعداد نتایج: 5978 فیلتر نتایج به سال:
Several commercially and ecologically important species in the southern Benguela have undergone southward and eastward shifts in their distributions over previous decades, most notably the small pelagic fish sardine Sardinops sagax and anchovy Engraulis encrasicolus. Understanding these changes and their implications is essential in implementing an ecosystem approach to fisheries in the souther...
Based on an extensive sampling regime from both nesting populations and bycatch, frequency analyses of mitochondrial (mt) DNA control region haplotypes in the Mediterranean were used to assess the genetic structure and stock composition of the loggerhead sea turtle, Caretta caretta, in different marine fisheries. The analyses show the following. (i) In drifting longline fisheries working in Med...
Stable isotopes of carbon and nitrogen were used to assess the relevance of 4 primary carbon sources (the macroalga Cystoseira balearica, decaying blades of the seagrass Posidonia oceanica, seagrass epiphytes and pelagic particulate organic matter [POM]) for consumers inhabiting 3 adjoining subtidal habitats in the Western Mediterranean: seagrass meadows, unvegetated sandy patches and the overl...
1. Stream fragmentation alters the structure of aquatic communities on a global scale, generally through loss of native species. Among riverscapes in the Great Plains of North America, stream fragmentation and hydrologic alteration (flow regulation and dewatering) are implicated in the decline of native fish diversity. 2. This study documents the spatio–temporal distribution of fish reproductiv...
Introduction 242 Biology of the Antarctic silverfish 243 Pleuragramma and the neutrally buoyant clade of nototheniids 243 The evolution of the neutrally buoyant clade and the Antarctic silverfish 243 Paedomorphy and the pelagic lifestyle of the Antarctic silverfish 244 Body morphology 244 Depth and geographic distribution 244 Early life history 245 Reproduction 246 Age, growth and mortality 247...
Diet of kingfish was examined in the Iranian coastal waters in the Persian Gulf and Oman Sea during the year 2005-08. With the examination of 1655 kingfish stomachs caught by drifting gillnets, it was revealed that this species fed three groups of preys including fish, Cephalopods, and Crustaceans, of which the fish group accounted for the highest in the frequency of number (99.3%) and in the f...
Some Fe and Fe-Mn deposits are found within sedimentary pelagic rocks and radiolarian cherts of the Khoy ophiolite. Mn-Fe mineralizations in Safo area north of Chalderan City are examples of them. In Safo area, deposition of manganese occurred as lense-like orebodies in different horizons within pelagic rocks. They are stratiform and have syn-sedimentary origin. Mineralogically, braunite, pyrol...
Escherichia coli and fecal coliform bacteria were isolated from five benthic and four pelagic fish species to determine their role in the fecal contamination of recreational waters. All fish were collected during fall 2006 from Southworth Marsh in the Duluth-Superior Harbor, a public beach that is commonly posted to minimize water contact due to high E. coli levels. Although fecal coliform bact...
We examined the relationship between the pelagic environment and the lunar timing of reproduction and recruitment of a coral reef fish by comparing patterns exhibited by fish under normal oceanographic conditions with patterns exhibited by fish that experienced significantly different pelagic conditions (i.e. encounter with meso-scale, low-salinity North Brazil Current [NBC] rings passing by th...
In species with complex life cycles, laboratory studies have shown that variations in the traits of settling larvae can affect post-settlement survival and influence recruitment and benthic− pelagic coupling. However, we still know little about the magnitude and spatial scale of natural trait variation. We studied spatial variation in body size and nutritional reserves (carbon, nitrogen and lip...
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