Related Experiment Video
Updated: May 31, 2026
08:13
RNA In situ Hybridization in Whole Mount Embryos and Cell Histology Adapted for Marine Elasmobranchs
Published on: April 12, 2013
The reproductive cycle of the roundel skate Raja texana
L J Williams1, A M Cicia, G B Pellegrin
1Marine Science Department, University of New England, Biddeford, ME 04005, USA. lwilliams8@une.edu
Journal of Fish Biology
|July 5, 2011
Abstract:
The reproductive cycle of Raja texana was determined from 63 females (510-630 mm total length, L(T)) and 81 males (355-546 mm L(T)) collected from the Gulf of Mexico. The results, based on follicle size, mature spermatocysts and gonadosomatic index (I(G)) suggests year-round reproductive activity.
Related Concept Videos
01:06Fixed Action Patterns
A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs.
00:51Energy Budgets
Organisms must balance energy intake with the energy required for growth, maintenance and reproduction. These trade-offs result in a variety of survivorship and reproductive strategies, including semelparity and iteroparity. Semelparous species, like annual plants, have only one reproductive episode in their lifetimes and consequently have short lifespans. Iteroparous species, by contrast, have many reproductive events during their lifetimes but have relatively few offspring. These two...
01:29Life Histories
Overview
01:17What is a Species?
Overview