Movement, connectivity and population structure of the intertidal fish Lipophrys pholis as revealed by otolith oxygen and carbon stable isotopes

ABSTRACT

The shanny Lipophrys pholis is an intertidal fish commonly found in Portuguese coastal waters. Spawning takes place from early autumn to mid spring, after which demersal eggs hatch and larvae disperse along the coast. Two to three months later, young juveniles return to the tide pools to settle. However, information on fish movement, habitat connectivity and population structure is scarce for this species. One hundred and twenty early juveniles (16–35 mm) were collected in April 2014 from six rocky beaches along the western and south Portuguese coasts (Agudela, Cabo do Mundo, Boa Nova, Peniche, Sines and Olhos de Água). δ¹⁸O and δ¹³C were determined by isotope-ratio mass spectrometry. Data were analysed to determine whether isotopic signatures could be used to assess the degree of separation between individuals collected from different locations. Mean δ¹³C and δ¹⁸O values ranged from −0.02‰ to 1.14‰ and −7.77‰ to −6.62‰, respectively. Both seawater temperature and salinity caused differences in otolith δ¹⁸O among the four main sampling areas. The variation among areas in δ¹³C was most likely related to slight differences in the diet, growth and metabolism of fish. The distinct isotopic signatures, at least for the northern and central areas, suggested low levels of connectivity across large spatial scales during the juvenile stage. Furthermore, similar isotopic signatures within the same area indicated some degree of larval oceanic retention at short spatial scales. This study suggests that stable isotope records in otoliths could provide information about the home residency, movements and habitat connectivity of intertidal fishes.

RESPONSIBLE EDITOR:

• Audrey Geffen

KEYWORDS:

• Blenniidae
• sagittae
• isotopic signatures
• fish life history

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Henrique Queiroga http://orcid.org/0000-0002-2338-0013

Alberto Teodorico Correia http://orcid.org/0000-0002-2831-025X

Additional information

Funding

This research was supported by the Fundação para a Ciência e a Tecnologia through the COMPETE – Operational Competitiveness Program and by national funds through FCT – Foundation for Science and Technology, under the projects ‘PEst-C/MAR/LA0015/2013’ and ‘PTDC/ BIA-BIC/120483/2010’.