Abstract
Gonad and pyloric caecum indices are widely used indicators of reproductive effort and nutritional condition in asteroids. Current methods of quantification generally require sacrificing multiple animals and the resulting reduction in local sea star density could have an unintended impact on benthic communities. Using the intertidal sea star Pisaster ochraceus, we developed and tested a method for estimating organ indices through the non-lethal sampling of single arms. Indices estimated via dissections of single arms accurately predicted the values obtained by sacrificing whole animals. In laboratory and field trials, we compared two methods of sampling single arms: (1) arm removal, and (2) organ extraction through an incision (without arm removal). Two years after these treatments, organs had regenerated in the affected arms of most sea stars, but were small relative to those in unmanipulated arms. The extent of organ recovery did not differ between the two treatments, but sea stars in the arm removal group were relocated in the field more frequently than those in the arm incision group. Our results suggest that sampling via the removal of single arms can be an effective, non-lethal method for estimating gonad and pyloric caecum indices in asteroids.
Original language | English (US) |
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Pages (from-to) | 372-380 |
Number of pages | 9 |
Journal | Invertebrate Biology |
Volume | 128 |
Issue number | 4 |
DOIs | |
State | Published - Sep 2009 |
Externally published | Yes |
Keywords
- Asteroidea
- Pisaster ochraceus
- Regeneration
- Reproduction
ASJC Scopus subject areas
- Animal Science and Zoology