Sternal Spines as a Characteristic for Differentiating between Females of some Pandalidae

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: McCrary, Jerry A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1971
• Subjects: General Medicine; Pandalus borealis; Alaska
• Online Access: http://dx.doi.org/10.1139/f71-014; http://www.nrcresearchpress.com/doi/pdf/10.1139/f71-014

A life-history study of four commercially important species of pandalid shrimps in Alaska shows that with the exception of one species, a morphological characteristic is possessed that is useful in estimating age and survival of certain females. Pandalus borealis, P. goniurus, P. hypsinotus, and Pandalopsis dispar possess a series of small spines located on the median ventral surface of the abdomen or sternites. With the exception of P. dispar, the sternal spines are present throughout the postlarval life of the shrimp until the first molt into breeding dress as a female. Only females that are sexually mature and are very near egg extrusion undergo this molt. At this time, the spines are either completely lost or reduced to minute protuberances. Between spawning seasons, females that extruded eggs during a prior spawning season can be easily identified as those that do not possess abdominal spines or possess only minute protuberances. Therefore, females that possess spines during any time of year are those that have not previously spawned. This characteristic is especially useful during the period between successive spawning seasons when it can be an effective tool in determining the number of females surviving one or more spawnings. Age and survival of pandalids is usually estimated through analysis of length-frequency ranges. This is often difficult with respect to females because of overlapping length ranges between age classes. Sternal spines may be useful in studies of other pandalids and families of shrimp.