Factors Influencing Habitat Selection of Three Cryptobenthic Clingfish Species in the Shallow North Adriatic Sea

Domen Trkov,Marcelo Kovačić,Lovrenc Lipej,Danijel Ivajnšič

doi:10.3390/jmse9080789

Abstract

Cryptobenthic fishes were often overlooked in the past due to their cryptic lifestyle, so knowledge of their ecology is still incomplete. One of the most poorly studied taxa of fishes in the Mediterranean Sea is clingfish. In this paper we examine the habitat preferences of three clingfish species (Lepadogaster lepadogaster, L. candolii, and Apletodon incognitus) occurring in the Gulf of Trieste (Northern Adriatic). The results show that all three species have a cryptic lifestyle and are well-segregated based on their depth distribution and macro- and microhabitat preferences. L. lepadogaster inhabits shallow waters of the lower mediolittoral and upper infralittoral, where it occurs on rocky bottoms under stones. L. candolii similarly occurs in the rocky infralittoral under stones, but below the lower distribution limit of L. lepadogaster, and in seagrass meadows, where it occupies empty seashells. Such hiding places in seagrass meadows are also occupied by A. incognitus, which mostly occurs below the lower distribution limit of L. candolii. Despite the overlap of depth and macrohabitat, the probability of individuals of two species encountering each other or competing in the same habitat is low when the depth range is combined with the microhabitat preferences of these species.

Highlights

Published: 22 July 2021Knowledge of species habitat preferences is essential, since it provides basic information about the suitability of the environment for a particular species [1]
Such hiding places in seagrass meadows are occupied by A. incognitus, which mostly occurs below the lower distribution limit of L. candolii
The sex ratio of 182 specimens of L. lepadogaster whose sex was determined showed no statistical differences (χ2 = 2.66; df = 1; p > α; α = 0.05), the ratio was 1:1.3 in favor of males

Summary

Introduction

Published: 22 July 2021Knowledge of species habitat preferences is essential, since it provides basic information about the suitability of the environment for a particular species [1]. The individual chooses the habitat that positively affects its fitness by providing a sufficient amount of adequate food [6] or allowing the possibility of increased survival due to reduced predation and mortality risk [7] Such habitat choice is known especially in cryptobenthic fish species, based on Miller’s definition [8] as those whose “small body size permits exploitation of restricted habitats, where food and shelter are obtained in, or in relation to, conditions of substrate complexity and/or restricted living space, with a physical barrier likely to be interposed between the small fish and sympatric predators”. Smith-Vaniz et al [10] concluded that around 64%

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