Age and growth determination of blackspotted smooth-hound (Mustelus punctulatus Risso, 1827) in the northern Adriatic Sea

Polak, Tanja (2015) Age and growth determination of blackspotted smooth-hound (Mustelus punctulatus Risso, 1827) in the northern Adriatic Sea. Diploma thesis, Faculty of Science > Department of Biology.

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Abstract

Blackspotted smooth-hound (Mustelus punctulatus Risso, 1827) belongs to a group of meso-predator sharks which are commercially exploited in the Adriatic Sea. According to the IUCN Red List blackspotted smooth-hound is classified as data deficient species, and very little is known about important aspects of its biology, including data on age and growth rate, which are missing for the Adriatic and Mediterranean Sea. Therefore, the aim of this study was to estimate the age and somatic growth rate, important for planning and sustainable management of this species. Age was estimated on sectioned vertebrae of 94 females (46.8 to 136.2 cm total body length, DT) and 93 males (44.6 to 126.5 cm DT), by applying skeletochronological method and morphometric measurements of vertebrae. Marginal increment analysis was conducted to assess patterns in seasonal growth, which justified the use of vertebrae for ageing of these sharks. Age-length data were used to estimate parameters for the von Bertalanffy growth function: k = 0.05/yr, Linf = 193.00 cm and to = -4.72 for females, and k = 0.08/yr, Linf = 144.00 cm and to = -3.95 for males. The oldest female was aged 20 years and male 15 years, while in the collected sample prevailed animals with age 3+ and 4+. According to these results, blackspotted smooth-hound is a slow-growing species, extremely vulnerable to exploitation.

Item Type: Thesis (Diploma thesis)
Keywords: elasmobranch, skeletochronology, the impact of fisheries, Triakidae, vertebrae, von Bertalanffy
Supervisor: Lacković Venturin, Gordana
Date: 2015
Number of Pages: 38
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Grozdana Sirotic
Date Deposited: 16 Apr 2015 12:48
Last Modified: 16 Feb 2016 14:02
URI: http://digre.pmf.unizg.hr/id/eprint/3820

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