Cryptic Lives of Conspicuous Animals: Otolith Chemistry Chronicles Life Histories of Coastal Lagoon Fishes

Frederick Feyrer,Rachel Johnson,Darren Fong,Matthew Young,Karin Limburg

doi:10.3389/fmars.2020.00417

Abstract

Bar-built coastal lagoons are dynamic ecosystems at the land-sea interface that are important habitats for a variety of species. This study examined the habitat ecology of two lagoon species, the imperiled Tidewater Goby (Eucyclogobius newberryi) and the Prickly Sculpin (Cottus asper) by reconstructing individual life histories from patterns in the concentration of the element Sr (as ratioed to Ca; Sr:Ca) in otoliths. Specific objectives were to (1) elucidate any movements of individual fishes among three primary habitat components of typical bar-built lagoon systems: coastal ocean, brackish lagoon, and freshwater watershed streams, and (2) determine if either species exhibited a consistent life history as defined by a stereotypical otolith Sr:Ca chronology, which could be indicative of a consistent range of salinity or temperature occupied through ontogeny. Results indicated that Tidewater Goby was a lagoon resident and that Prickly Sculpin exhibited migrations between lagoon and watershed stream habitats. There was no strong evidence in either species of ocean occupancy or of a stereotypical Sr:Ca chronology, the latter suggesting the full range of available lagoon habitat in terms of salinity and temperature was likely utilized at all life stages. These findings add to the body of evidence that bar-built lagoons are not isolated habitats and should be managed holistically with adjoining watershed and marine environments to ensure habitat connectivity across the landscape.

Highlights

Coastal lagoons are dynamic ecosystems at the land-sea interface that are important habitats for a variety of species (Barnes, 1980; Yáñez-Arancibia, 1985; Pérez-Ruzafa et al, 2019)
An increasingly popular tool to address the challenge of tracking fish among aquatic ecosystems and elucidating coastal dispersal/migration is the application of otolith chemistry as a natural marker of fish life history (Elsdon et al, 2008; Walther and Limburg, 2012; Shao et al, 2018)
The objective of this study was to elucidate the habitat ecology of two fish species common to bar-built lagoons in CA, United States, using the chemical composition of their otoliths: the small-bodied, demersal fishes Tidewater Goby (Eucyclogobius newberryi) and Prickly Sculpin (Cottus asper)

Summary

Introduction

Coastal lagoons are dynamic ecosystems at the land-sea interface that are important habitats for a variety of species (Barnes, 1980; Yáñez-Arancibia, 1985; Pérez-Ruzafa et al, 2019). They can be generally characterized as relatively small, shallow habitats typically connected to the ocean by a small inlet and exhibit a broad range of physical habitat and water quality conditions (Kjerfve, 1994). Quantifying the habitat and movements of small, demersal fishes is a challenge in marine science and presents obstacles to fully understanding the ecology of coastal lagoons and their biota.

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Methods

Conclusion