Length–weight relationships, morphometric characteristics, and thorniness of thorny skate (Raja radiata) from the northwest Atlantic. Journal of Northwest Atlantic Fishery Science 7(2):89–98
Research on length-weight, morphometries and thorniness of thorny skate in the Northwest Atlantic was carried out in 1947-72. Length-weight data for the northern and southern regions, where sexual maturity begins at smaller and larger sizes respectively, were compared by sex and maturity. Slopes of...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1987
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.631.2465 http://journal.nafo.int/j07/templeman3.pdf |
| Summary: | Research on length-weight, morphometries and thorniness of thorny skate in the Northwest Atlantic was carried out in 1947-72. Length-weight data for the northern and southern regions, where sexual maturity begins at smaller and larger sizes respectively, were compared by sex and maturity. Slopes of the log-log length-weight regressions were lower for matures than for immatures, and, consequently, mature fish had lower average weights than immatures of the larger size-groups. Morphometric characteristics by sex and maturity, as percentages of total length of fish, indicated that tail length was shorter than disc length in mature skate, and that length from snout to posterior tip of pelvic fin was greater, and head width across mid-pupils and distance between the fifth pair of gill slits were less in mature males than in mature females, immature males and immature females. Dorsal thorniness decreased with increase in skate length and advance toward sexual maturity, with males showing a much greater and earlier loss of thorniness than females. Thorniness decreased at smaller sizes in northern waters, where sexual maturity occurs at small sizes, than in southern waters, where sexual maturity occurs at larger sizes. |
|---|