First age and growth estimates in the deep water shark, Etmopterus spinax (Linnaeus, 1758), by deep coned vertebral analysis
Gennari, E.; Scacco, U. (2007). First age and growth estimates in the deep water shark, Etmopterus spinax (Linnaeus, 1758), by deep coned vertebral analysis. Mar. Biol. (Berl.) 152(5): 1207-1214. http://dx.doi.org/10.1007/s00227-007-0769-y
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
|  |
| Abstract |
The velvet belly Etmopterus spinax (Linnaeus, 1758) is a deep water bottom-dwelling species very common in the western Mediterranean sea. This species is a portion of the by-catch of the red shrimps and Norway lobsters otter trawl fisheries on the meso and ipo-bathyal grounds. A new, simple, rapid, and inexpensive vertebral preparation method was used on a total of 241 specimens, sampled throughout 2000. Post-cranial portions of vertebral column were removed and vertebrae were prepared for ageing readings. Band pair counts ranged from 0 to 9 in females, and from 0 to 7 in males. Von Bertalanffy growth equations estimated for both sexes suggested a higher longevity for females (males: L 8 = 394.3 mm k = 0.19 t 0 = -1.41 L 0 = 92.7 mm A 99 = 18.24 years; females: L 8 = 450 mm k = 0.16 t 0 = -1.09 L 0 = 72 mm A 99 = 21.66 years). Age estimations are discussed in the context of deep water shark species. This is the first successful attempt at delineating faint growth bands in the poorly calcified deep coned vertebrae of E. spinax. This technique may be used in other difficult poorly calcified species. |
|
