To study some early life history traits of Lipophrys pholis, 110 recruits (TL ≤ 30 mm) were collected in April and May 2013 during the low tide periods in four rocky beaches along the west (Cabo do Mundo, Peniche and Vale do Homem) and south (Olhos de Água) Portuguese coasts. Pelagic larval duration, size at settlement and age at coastal recruitment were back-calculated from the microstructure of otoliths. Pelagic larval duration estimated from micro-increment counts until the settlement marks ranged from 57 to 73 days and showed a latitudinal reduction trend from north to south. This variable seems to be related in 30% with the regional seawater temperatures probably through the direct effect on the somatic growth. Settlement sizes (~19 mm) did not show any regional differences suggesting that this is a more conservative character within species. The mean age at coastal recruitment varied between 69 and 93 days, but northern individuals were recruited at an older age. Back-calculated spawning, hatching and settlement dates appear to be unrelated to the lunar cycle for L. pholis.
To assess the periodicity of micro-increment formation in otoliths of Lipophrys pholis, 90 early juveniles were immersed in alizarin red S or tetracycline hydrochloride for 24 h and sacrificed after 10, 20 and 30 days. The number of micro-increments viewed under light microscopy was significantly related to the duration of the experimental period, and the slopes of the linear regressions were not significantly different from 1. This study indicates that micro-increments in sagittae were deposited daily and can be used as reliable sources of age information for L. pholis.
Summary
Age, growth, sex and gonadal maturation of the shanny, Liphorys pholis, were determined in specimens caught in a rocky intertidal area in northern Portugal in order to provide essential ecological data on the species. This study represents the first available reference in the literature for L. pholis in a southern European location. Totals of 251 individuals (115 females, 99 males, 37 undetermined; total length: 30–172 mm) were collected seasonally (November 2013, March, June, and September 2014) in a northern Portuguese rocky beach (Póvoa do Varzim: 41°23′47.79″N; 08°46′45.48″W) using fine‐mesh aquarium fishnets during low tides. Marginal increment analysis showed that one translucent and one opaque zone was formed each year in the sagittal otoliths. Ages of L. pholis ranged from 0 to 6 years. Males were larger and older than females. The von Bertalanffy growth equation parameters considering all individuals were L∞ = 184 mm, K = 0.26 mm/year, t0 = −1.34. The annual variation of the fish condition and hepatosomatic indexes appeared to be related to the mobilization of the somatic reserves prior to reproduction. Maximum gonadosomatic index for males and females coincided with the breeding seasons (November and March). The sex ratio was close to 1:1, all maturity stages included. Furthermore, some stages of sexual development in males and females were observed during the same season, and several germinal cells were also observed at the same time within a single ovary or testis, indicating that L. pholis is an asynchronous and multiple spawner. Maturation for both sexes appears to be around 70 mm TL and prior to reaching 1 year of age.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.