Homing in rocky intertidal fish. Are Lipophrys pholis L. able to perform true navigation?

Abstract

Although navigation is common in many animals, only a few perform true navigation, meaning that they have the ability to return to a given place by relying on indirect cues obtained at the release site (i.e., by relying on information from a ''map and compass'' mechanism). The common intertidal fish, Lipophrys pholis, is thought to have homing abilities through a mechanism that primarily makes use of familiar landmarks (i.e., piloting). Anecdotal reports that individuals return to their home pools after release at unfamiliar sites suggest that L. pholis might use cues collected at the release site to find their way back (i.e., they might use map and compass information). Using a completely artificial setup, we tested the homing abilities of L. pholis as a function of age, sex, and familiarity with the release site. The findings showed that motivation for homing is present only in the adult phase and is independent of sex and/or familiarity with the release site. Moreover, adults released at a completely unfamiliar place oriented themselves in a direction roughly similar to that of their home pools. The fact that L. pholis were tested in a complete artificial environment means that hydrodynamic cues can be excluded as playing a role in this process and restricts the candidate options (e.g., magnetic cues). The ability to perform navigation based on a ''map and compass'' mechanism raises many interesting questions about the learning process, once these individuals have restricted home ranges during their lives. In vertebrate navigation, the cues used during the navigation process are a question of debate, and L. pholis offers an outstanding model to test hypotheses and ultimately provide answers.

Homing behaviour of rock pool blennyParablennius parvicornis(Pisces: Blenniidae)

“…Both sexes have different home ranges and this seems to be connected with morphological differences in brain areas related to orientation (Costa et al 2011). Their homing abilities could also be modulated by age because of breeding motivation or familiarity with the release site as has been demonstrated in other blennies (Jorge et al 2011). In this paper we studied the homing abilities of the rock pool blenny according to its sex and length.…”

“…As have many rocky intertidal fish, several blenny species have been shown to have good homing abilities (Santos et al 1989;Jorge et al 2011), and our aim is to determine whether P. parvicornis also has this ability. This blenny is an intertidal fish living in rock pools during low tide (Bath 1990).…”

“…Generally, displacement experiments consist of tagging fish, relocating them at distances varying from 1 to several hundred metres and observing their position at low tide to record movement patterns of identifiable individuals (Santos and Almada 1988;Matthews 1990;Montero et al 2004;Mitamura et al 2009). Alternatively, mechanisms prevalent in fish orientation can be studied in artificial environments, to highlight the cues relevant to homing (Jorge et al 2011).…”

“…Knowing the home range of intertidal species is important to implement faunal conservation strategies, particularly on islands where human pressure is high in coastal areas. Homing in intertidal zones is studied in the field with displacement experiments White and Brown 2013), or in a completely artificial environment (Jorge et al 2011). Generally, displacement experiments consist of tagging fish, relocating them at distances varying from 1 to several hundred metres and observing their position at low tide to record movement patterns of identifiable individuals (Santos and Almada 1988;Matthews 1990;Montero et al 2004;Mitamura et al 2009).…”

Spatial learning based on visual landmarks in the freshwater blenny Salaria fluviatilis (Asso, 1801)

“…The ability to include previous experiences within spatial behaviour is essential 51 for certain fish to survive and to adapt to environmental changes (Dodson, 1988). This 52 permits them to perform behaviours such as homing behaviour (Thyssen, 2010;Jorge, 53 Almada, Gonçalves, Duarte-Coelho, & Almada, 2012) and to remember and use visual 54 landmarks (Burt & Macias García, 2003). 55 An extensive bibliography on spatial learning based on visual landmarks in fish is 56 available.…”