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Several ecological, morphological and behavioural aspects of territorial males of Parablennius incognitus

Meijer-Kuiper, W. (1992) Several ecological, morphological and behavioural aspects of territorial males of Parablennius incognitus. Master's Thesis / Essay, Biology.

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Abstract

In this research, several ecological, morphological and ethological aspects of Parablennius incognitus males, which are territorial between May and August, were studied. Nest sites of territorial males are cavities in rocks and oscula of sponges, between depths of 0.5 and 4.8 in. These holes are situated in sunlit places not highly exposed to waves and are usually surrounded by a low vegetation of algae. The hole entrance (usually round) generally lies higher than the end of the hole. Minimum entrance diameter varies between 0.73 and 1.68 cm, maximum diameter between 0.73 and 4.27 cm, hole, depth between 1.54 and 5.87 cm and hole volume between 2 and 20 ml (respective means are 1.13 cm, 1.56 cm, 3.24 cm and 6.25 ml). Most territorial B.incognitus males leave their natural hole during July. Glass test-tubes, offered as artificial holes, are occupied by Blennius males from May onwards and are deserted by the end of August. Most B.incognitus males start to occupy a tube between late May and early June; this may depend on the water temperature, which is ±16°C during that time. Males occupy tubes at depths of 0.4, 0.9 and 1.6 in, but not at 2.1 in. B.sphinx mostly occupies large sized tubes at the former two depths, whilst B.incognitus occupies more large than small sized test-tubes with increasing depth. By the end of August, territorial males are 3.7-5.0 cm in length, weigh 0.49-1.27 g and have gonads of 0.003-0.008 g (respective means are 4.3 cm, 0.85 g and 0.0047 g). At the end of the season, smaller (lighter) males tend to have relatively heavy gonads compared to larger (heavier) males. Non-social activities displayed by B.incognitus, such as the manner of swimming, feeding, scratching and resting, are common to other blennies. Social behaviours, such as agonistic and courtship display, interspecific and intraspecific interaction, are more specific. Territorial males spend most of the day at rest (outwardly), followed by being inside their hole and by ventilating the nest (with eggs) using lateral fins; these behaviours are displayed in similar amounts of time throughout the day (as is interspecific interaction). Sexual behaviours and agonistic interactions mostly take place before noon; swimming, feeding and scratching occur most after noon. This species is diurnal, retreating into holes during the evening to rest during the dark period.

Item Type: Thesis (Master's Thesis / Essay)
Degree programme: Biology
Thesis type: Master's Thesis / Essay
Language: English
Date Deposited: 15 Feb 2018 07:47
Last Modified: 15 Feb 2018 07:47
URI: http://fse.studenttheses.ub.rug.nl/id/eprint/9963

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