The effects of mate switching tacticon reproductive performance of the severum cichlid, Herosseverus
نویسندگان
چکیده مقاله:
This study investigated the effects of mate switching on the reproductive performance of the severum cichlid, Herosseverus, by advancing the egg and larval production in hatcheries. Two reproductive tactic treatments of “monogamous pair” and “mate switching” were used for evaluating 4 reproductive traits of egg production, hatching rate, spawning intervals, and starvation tolerance of the larvae in 6 spawning activities. The number of eggs was not significantly different between the two reproductive tactic treatments in the 6 spawning activities, but the spawning intervals, hatching rate, and survival activity index were all significantly different. Daily average egg and larval production in the mate switching treatment were estimated to be 87.3 eggs and 43.1 larvae per pair of fish, respectively, which was 2.89 times and 1.99 times of those in the monogamous pair treatment, who produced about 30.2 eggs and 21.6 larvae per pair. Our results clearly showed that the reproductive tactic of mate switching is a suitable method for increasing the egg and larval production rate of the severum cichlid.
منابع مشابه
the effects of planning on accuracy and complexity of iranian efl students’ written narrative task performance
this study compared the different effects of form-focused guided planning vs. meaning-focused guided planning on iranian pre-intermediate students’ task performance. the study lasted for three weeks and concentrated on eight english structures. forty five pre-intermediate iranian students were randomly assigned to three groups of guided planning focus-on-form group (gpfg), guided planning focus...
15 صفحه اولthe effects of time planning and task complexity on accuracy of narrative task performance
هدف اصلی این تحقیق بررسی تاثیر برنامه ریزی زمانی، هم چنین افزایش میزان پیچیدگی تکالیف در نظر گرفته شده بصورت همزمان، بر دقت و صحت و پیچیدگی عملکرد نوشتاری زبان آموزان می باشد. بدین منظور، 50 نفر از دانش آموزان دختر در رده ی سنی 16 الی 18 سال به عنوان شرکت کنندگان در این زمینه ی تحقیق در نظر گرفته شدند و به دو گروه آزمایشی و کنترل بصورت اتفاقی تقسیم شدند. اعضای گروه آزمایشی هر دو تکلیف ساده و پی...
the effects of changing roughness on the flow structure in the bends
flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...
the effects of error correction methods on pronunciation accuracy
هدف از انجام این تحقیق مشخص کردن موثرترین متد اصلاح خطا بر روی دقت آهنگ و تاکید تلفظ کلمه در زبان انگلیسی بود. این تحقیق با پیاده کردن چهار متد ارائه اصلاح خطا در چهار گروه، سه گروه آزمایشی و یک گروه تحت کنترل، انجام شد که گروه های فوق الذکر شامل دانشجویان سطح بالای متوسط کتاب اول passages بودند. گروه اول شامل 15، دوم 14، سوم 15 و آخرین 16 دانشجو بودند. دوره مربوطه به مدت 10 هفته ادامه یافت و د...
15 صفحه اولon the effects of pictorial clues on the efl learners listening comprehension development
the following null hypothesis was proposed: there is no significant difference between the efl students listening comprehension development receiving pictorial cues and those receiving no cuse. to test the null hypothesis, 52 male and femal freshmen students of medicine studing at iran university of medical scinces were randomly selected from a total population of 72 students. to ensure that th...
15 صفحه اولمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ذخیره در منابع من قبلا به منابع من ذحیره شده{@ msg_add @}
عنوان ژورنال
دوره 13 شماره None
صفحات 1056- 1068
تاریخ انتشار 2014-10
با دنبال کردن یک ژورنال هنگامی که شماره جدید این ژورنال منتشر می شود به شما از طریق ایمیل اطلاع داده می شود.
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023