The annual cycle of spermatogenesis in Lipophrys pholis (Blenniidae), a recently proposed sentinel species for pollution monitoring

Abstract

Since reproductive parameters are common endpoints in pollution monitoring, the description of the spermatogenesis of Lipophrys pholis, a recently proposed sentinel species, is of critical importance. Mature males were used to determine the annual maturation cycle, using a stereological approach. The spermatogenic cycle was classified into three stages: early spermatogenesis (May), mid spermatogenesis (September), and spawning (November and January). The testes were asynchronously arranged with various cell types observable during all seasons, although in different proportions. Gonadosomatic index and spermatozoa proportions confirmed the established reproductive season. Differences between the sampled populations and those from septentrional locations are discussed, namely the absence of ''resting'' and ''spent'' periods.

Age, growth and sex of the shanny, Lipophrys pholis (Linnaeus, 1758) (Teleostei, Blenniidae), from the NW coast of Portugal

“…Similar results were observed for males capable of multiple spawning episodes. Such results also agree with previous studies on the species (Ferreira et al., , ). Furthermore, the sex ratio of L. pholis observed here was most likely 1:1 throughout the year.…”

“…Histological observations showed that almost all stages of gonadal sexual development were present simultaneously in the ovaries and testes throughout the year. The observed five main stages of maturity corresponded to the existing literature for this species (Ferreira et al., , ; Ismail et al., 1990; Qasim, ).…”

“…The maximum and minimum GSI values for both adult females and males were recorded simultaneously during November and March, which also coincided with the higher percentage of spawning individuals. Observations from previous studies (Ferreira et al., , ) corroborate these findings, since most females and males are ready to spawn in November. Lower observed GSI values in our study were also recorded in June.…”

“…Sections were stained with haematoxylin–eosin, and examined at 40–1,000× by light microscopy (Olympus, CX41). Microphotographs were taken with a digital USB camera (Olympus, SC 30) in order to assign sex and gonadal maturity stages based on previous works (Ferreira, Santos, Reis‐Henriques, Vieira, & Monteiro, ; Ferreira et al., ; Ismail et al., ; Qasim, ; Santos, ). Individuals were considered as undetermined where it was impossible to identify the sex or developmental stage.…”

The annual cycle of oogenesis in the shanny, <i>Lipophrys pholis</i> (Pisces: Blenniidae)

“…Interestingly, GSI also produced fairly good results for L. pholis males (Ferreira et al 2011). The stereological approach, although highlighting several similarities between sites and sampling seasons (e.g.…”