Date of Award

1996

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

First Advisor

J. Michael Fitzsimons

Abstract

Community structure and relative habitat preferences of intertidal fishes from the eastern Canary Islands of Fuerteventura, Gran Canaria, and Lanzarote were examined in a study of 354 tidepools at 33 localities. Habitat use and behavior of the most abundant fish Mauligobius maderensis were examined on Gran Canaria and Lanzarote. Of the 27 species encountered, 11 were common to each of the islands. The most abundant species were: M. maderensis, Parablennius parvicornis, Gobius paganellus, Coryphoblennius galerita, and Chelon labrosus. In a Two-way indicator species analysis Fuerteventura and Lanzarote localities clustered together. The same analysis differentiated between species that inhabited the upper intertidal shore and those that associated with lower shore pools. Canonical Correspondence Analysis revealed a weak relationship between abundant species and habitat preference variables. Transient species (e.g., Abudefduf luridus, Scorpaena maderensis, and Tripterygion delaisi) showed a greater affinity with variables: mean standard length (SL), number of species, pool depth, shelter, and volume. When habitat use of M. maderensis was assessed in terms of body size, larger individuals showed an affinity for downshore pools. A general downshore movement associated with increasing size was evident from the elevational distribution of size classes of M. maderensis and provides a mechanism by which the habitat heterogeneity of the rocky shore may be exploited by M. maderensis. Although the abundance and broad intertidal distribution of M. maderensis are consistent with a generalist strategy, differential habitat use by the size classes of M. maderensis supports the hypothesis that habitat use is constrained by size. Males of M. maderensis were territorial. Territoriality was associated solely with reproduction and did not involve the defense of food resources. In territorial encounters between resident males and intruding males, resident fish were never displaced. An intruding male decreased its probability of being displaced by responding to the defensive displays of the resident male with a "face-away" posture. Males were the sole participants in nest-guarding.

ISBN

9780591035087

Pages

143

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