Variation in population structure and life-history parameters of steentjies Spondyliosoma emarginatum: effects of exploitation and biogeography

Published source details Tunley K.L., Attwood C.G., Moloney C.L. & Fairhurst L. (2009) Variation in population structure and life-history parameters of steentjies Spondyliosoma emarginatum: effects of exploitation and biogeography. African Journal of Marine Science, 31, 133-143.
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This study is summarised as evidence for the following.

	Action	Category
	Control human activity in a marine protected area with a zonation system of restrictions Action Link

Control human activity in a marine protected area with a zonation system of restrictions

A site comparison study in 2006–2007 of three seabed sites in the Atlantic Ocean, off South Africa (Tunley et al. 2009) found that in a multi-zoned protected area steentjies Spondyliosoma emarginatum in a zone closed to all fishing were larger, and had a different age and sex structure, than a fished multipurpose zone and both showed differences to a distant unprotected fished site with low steentjie exploitation. Overall, average size of steentjies was larger in the no-fishing protected zone than the fished zone (non-fished: 238–271 mm, fished: 210–262 mm) and both were larger compared to a distant unprotected fished site (187–218 mm). The frequency of females was highest in the fished protected zone (reserve non-fished: 53%, reserve fished: 83%, distant non-targeted: 39%) and the frequency of males was highest at the distant site (reserve non-fished: 17%, reserve fished: 5%, distant non-targeted: 57%) (transitional males make up the difference). In addition, larger and older females and larger male steentjies were fewer in the fished protected zone compared to the no-fishing zone (data presented graphically). Steentjies were captured by line fishing at two sites inside Langebaan Lagoon reserve in April-September 2007. One site was a no-fishing zone permitting sailing and canoeing only and one was a multi-purpose recreational zone permitting fishing and other activities (year of implementation not reported). Steentjies were also caught at a third site off Struisbaai by research vessel from November 2006 to April 2007. Commercial and recreational fishing is permitted but steentjies are not generally targeted. A total of 319 steentjies were sampled for length, sex and age.

(Summarised by: Khatija Alliji)