Reproduction biology of large-scaled gurnard Lepidotrigla cavillone (Lacepède, 1801) from the southern Adriatic Sea (Croatia)

Abstract

Summary The aim of this study was to define the reproductive characteristics of the large‐scaled gurnard Lepidotrigla cavillone in the Adriatic Sea in order to understand the annual cycle of its reproductive development. A total of 1105 individuals were collected in the period from October 2011 to September 2012. The size of the samples ranged from 7.6 to 15.2 cm in total length with a male to female ratio of 0.83:1. Based on monthly values of the gonadosomatic index it was determined that the large‐scaled gurnard has a long spawning period extending from February to September with two peaks, one in May and another in August. Histological analysis demonstrated continuous reproductive activity since all stages of oocyte development were present in ovaries throughout the year with no inactive or resting periods. Spawning period in females was characterized by the increased number of oocytes in migratory nucleus or hydrated stage with the oocyte diameter ranging from 608.0 to 776.7 μm and in males with the abundance of spermatozoa. This study presents first information on the reproductive cycle of Lepidotrigla cavillone in the Adriatic Sea and contributes to our understanding of the biology of this important discard species necessary for its future stock management.

Reproductive strategy of spiny gurnard Lepidotrigla dieuzeidei Blanc and Hureau, 1973 from the south-eastern Adriatic Sea

“…dieuzeidei in the south Adriatic shows a prolonged spawning period (November to July), which is common among gurnards (LEWIS & YERGER, 1976;MCBRIDE & ABLE, 1994). This observation is in accordance with the results of a previous study on L. cavillone in the Adriatic Sea which reported maximum gonadal activity between January and August (DOBROSLAVIĆ et al, 2015). According to available literature spawning period in other Triglidae is shorter (MUÑOZ et al, 2001;MUÑOZ et al, 2003;İLHAN & TOĞULGA, 2007;BOUDAYA et al, 2008;VALLISNERI et al, 2014; -SERAFY et al, 2015) than those recorded for species of gender Lepidotrigla in the Adraitic Sea.…”

“…According to available literature spawning period in other Triglidae is shorter (MUÑOZ et al, 2001;MUÑOZ et al, 2003;İLHAN & TOĞULGA, 2007;BOUDAYA et al, 2008;VALLISNERI et al, 2014; -SERAFY et al, 2015) than those recorded for species of gender Lepidotrigla in the Adraitic Sea. Also, the male gonads of L. dieuzeidei were found significantly smaller than female gonads; the same characteristic was observed in previous studies of L. cavillone (COLLOCA et al, 1997;İLKAYAZ et al, 2010;DOBROSLAVIĆ et al, 2015).…”

“…A quantitative method of measuring the size of oocytes (expressed as oocyte diameter) was also employed in this study and it followed the pattern observed using qualitative histological methods. The maximum oocyte diameter recorded for L. dieuzeidei was 946.05 µm, which coincides with the maximum size report for L. cavillone at 974.85 µm (DOBROSLAVIĆ et al, 2015). The quantitative analysis of female gonads showed a continuous representation of all oocyte sizes throughout the year with no visible gaps between the first and the second stage of development, meaning that previtellogenic and vitellogenic oocytes were always present in the gonads.…”

“…The dominance of females recorded in this study was already observed for the majority of species within the Triglidae family (İLHAN & TOĞULGA, 2007;BOUDAYA et al, 2008;BEN JRAD et al, 2010;MARRIOTT, et al, 2010;VALLISNERI et al, 2011;DOBROSLAVIĆ et al, 2015). Fishing time and used fishing gear can enhance further fluctuation of male to female ratio in the population (RICK-ER, 1973).…”

“…Based on monthly gonad analysis, this study showed that L. dieuzeidei has multiple synchronous development of ovaries with multiple spawning events. This was also recorded for longfin gurnard C. obscura (MUÑOZ et al, 2001) and large-scaled gurnard L. cavillone (DOBROSLAVIĆ et al, 2015). The ovaries were always represented with a group of primary oocytes and a diverse population of vitellogenic oocytes, which are each specially recruited during the final stages of maturation in uniform or uneven phases.…”