Carlotta Mazzoldi

This study describes the first ever reported direct observation of a pair spawning event and the reproductive liveries of the white grouper, Epinephelus aeneus. Spawning took place on a rocky bank located in the Marine Protected Area (MPA) of Tavolara-Punta Coda Cavallo (NE Sardinia, Italy), in the Western Mediterranean Sea. In the evening of August 4th, 2018, the spawning of two large-sized individuals (~90 cm total length), displaying distinct colour patterns, was observed using SCUBA diving. This direct observation is the first record of E. aeneus male reproductive livery, characterized by a darker coloration on the head, the dorsal part of the body and the caudal fin. In addition, information on the environmental conditions in which reproduction occurred was collected. At the study site, relatively high seawater temperatures were recorded at the time of the E. aeneus spawning (24 °C at 24.7 m), as well as over the 2018 summer months (July-September), even in deep waters (>35 ...

The life history traits of bathydraconids, deep-living fishes distributed all around the Antarctic continent, are poorly known. In particular, very few data are available on the relatively rare genera Akarotaxis and Bathydraco. With the aim to fill this gap, sagittal otoliths and gonads were analysed to assess individual age and reproductive features of Akarotaxis nudiceps (Waite, 1916), Bathydraco macrolepis Boulenger 1907 and Bathydraco marri Norman, 1938 collected in the Weddell Sea. Based on the annual growth increment patterns, age estimates ranged between 6–11, 5–11 and 8–11 years for A. nudiceps, B. macrolepis and B. marri, respectively. Most of the gametogenetic processes could be described based on gonad histology for both sexes. Females shared the reproductive features commonly reported in notothenioids, such as group-synchronous ovary development and prolonged gametogenesis. Total fecundity estimates were comparable between the two species of Bathydraco (1500–2500 eggs/fe...

In many social species, when an individual is associated with familiar conspecifics, it displays an array of behaviours that may confer benefits (e.g., increased boldness and faster habituation to novel environments). In fish, these effects of familiarity have been studied using individuals of only one sex or juveniles. Since shoals often vary regarding sex composition and males and females show different social behaviours, we hypothesised that social familiarity's effects vary with group sex composition. We tested this hypothesis by comparing the exploratory behaviour of groups of two females, two males, and one male and one female Mediterranean killifish, Aphanius fasciatus, which were either familiar or unfamiliar. Pairs of familiar females were bolder than pairs of unfamiliar females, whereas males showed the opposite trend. Pairs of familiar females also showed faster habituation to the novel environment and, at the beginning of the test, were more cohesive compared to pair...

No-take fishery zones are expected not only to protect biodiversity, but also to act as a tool for fishery management. In 2002, a no-take zone was established in the northern Adriatic Sea, ground for the Chioggia's fleet, one of the main Italian fisheries. The protected zone is actually a network of four areas (from 1.3 to 22 km 2), constituted by offshore rocky outcrops surrounded by sandy-muddy bottom (depth: 18-24m). Establishment was primarily due to the environmental uniqueness, while its role in fishery management was poorly assessed. In 2004 and 2005, summer underwater visual census samplings on fish assemblages were performed on 12 sites, 8 inside and 4 outside the protected area to analyse spatial and temporal variability. A total of 33 species, belonging to 15 families were recorded. No differences between protected and unprotected sites, or between years in the protected ones, were detected. Spatial patterns of ecological indices and fish assemblage composition (multi...

The understanding of marine reserves functioning suffers of crucial gaps in scientific knowledge, such as data on environmental variables, physico-chemical properties of the water column, and plankton populations. • A no-take zone was established in 2002 in the northern Adriatic Sea, a basin deeply harvested by fishery. The protected zone is composed of four areas (size: 1.3÷22km 2) located 3÷8 miles off the Italian coast and constituted by rocky outcrops (depth: 17÷24m) surrounded by sandy-muddy bottom. • From February 2006 a pilot, interdisciplinary project was started, with the goal to integrate previous data (see grey box below) with measurements of physical and chemical parameters and estimation of composition and abundances of phyto-, zoo-and ichthyoplankton on a wider scale. • Eight sampling stations were chosen on outcrops inside (n=4) and outside (n=4) the protected areas, presenting a northern-southern distribution and different distances from the main rivers. • Cruises we...

ABSTRACT Accessory structures to the male reproductive system are known in several fami-lies of teleost, but their role in sperm production patterns and fertilization dynamics is still un-clear. The intraspecific variability in seminal vesicles, shown by the grass goby Zosterisessor ophiocephalus, presents an opportunity to examine both its possible correlation to alternative male mating tactics and the function of these accessory structures. In this species, males are known to release sperm in the form of sperm trails, bands of mucosubstances in which sperm are embedded. Surgical removal of seminal vesicles and histochemistry demonstrate that mucins, involved in the production of sperm trails, are secreted by the seminal vesicles. Gametes show a high longev-ity; sperm motility lasts on average 80 minutes. Eggs can be fertilized for several hours and do not need to be laid over trails because sperm are able to reach them via the surrounding water. Gonosomatic and seminal vesicle somatic indices, histology and histochemistry of gonads and seminal vesicles, sperm counts, and sperm trail longevity, suggest the presence of alternative male mating tactics in this species. Larger males have smaller testes and larger seminal vesicles compared to those of smaller males. The major role of seminal vesicles is mucin secretion in larger males, sperm storage in smaller ones. Trails of larger males last longer and release sperm more constantly over time than those of smaller males. Overall differences between males support the presence of differences in the intensity of sperm competition, with larger males performing nesting behaviour while smaller ones sneak spawnings. J. Exp. Zool. 283:81– 90, 1999. © 1999 Wiley-Liss, Inc. Sperm competition, defined as the competition between the sperm of two or more males to fertil-ize the eggs of a female (Parker, '70), is well known to strongly influence not only the behaviour of males but also their reproductive anatomy and physiology (Smith, '84). In fish, it has been dem-onstrated that males exposed to higher levels of sperm competition have relatively larger testes and release an absolute higher number of sperm per spawn or ejaculate (Robertson and Warner, '78; Warner and Robertson, '78; Shapiro et al., '94; Stockley et al., '97; Petersen and Warner, '98). Testes and the associated structures of the male reproductive system have roles that go beyond sperm production. The production of substances that may serve hormonal or pheromonal roles, fa-cilitating sperm delivery and sperm storage, are important roles of the testis and its accessory structures (Fishelson, '91; Van den Hurk and Resink, '92). These accessory structures often are embedded within the testes, or lay adjacent to them. It is unclear how these structures are related to sperm production patterns, both evolu-tionarily and functionally. Current sperm compe-tition models that use gonosomatic indices to estimate sperm production within or between spe-cies assume that functions other than sperm pro-duction are either not important or are constant across comparisons. The family Gobiidae is a large family of small, freshwater and marine species with demersal spawning and male parental care. Male sperm duct glands, usually called seminal vesicles, are accessory structures of the reproductive appara-tus of all species of the suborder Gobioidea (Miller, '92). However, neither the significance of their

The cuttlefish Sepia officinalis is an important fishery resource in the Northern Adriatic Sea (Italy). During reproduction, fertilised eggs are released by adult females in coastal waters and embryo development can take over two months. During this period, embryos rely on nutrients and other substances, such as immune factors, provided by the female in egg yolk. In cephalopods in general, and specifically in the common cuttlefish, little information is available on yolk biochemical composition and substances included in egg envelopment. In the present study, the main biochemical components of egg yolk and the presence of antimicrobial substances in egg envelopment of S. officinalis were determined for the first time. Statistically significant differences in total egg weight and egg yolk weight were observed among batches from different females. Egg and yolk weights were positively correlated, with yolk representing the 13% (±5%) of the total egg weight. Total proteins were the main biochemical component (46%) of egg yolk, followed by total carbohydrates plus glycogen (39%) and lipids (15%). Statistically significant differences among batches were recorded in egg yolk total protein amounts, lipids, carbohydrates and glycogen, but no correlations were found between egg yolk weight and the biochemical components. The Petri dish and the quantitative spectrophotometric assays revealed the presence of lysozyme-like activity in egg gelatinous envelopment.

ABSTRACT The role of natural and sexual selection in generating variability in biological traits between populations represents an intriguing issue in evolutionary biology. Considering their occurrence in different environments and the extensive incidence of post-copulatory sexual selection, elasmobranchs represent an interesting, yet still poorly investigated group. In this study, the life history and reproductive traits of two populations of Scyliorhinus canicula from the northern Adriatic Sea and the Strait of Sicily were compared. Differences in maximum size and size at sexual maturity were observed. The two populations also displayed differences in male and female genitalia. Males in the northern Adriatic Sea presented heavier testes, longer epididymis, seminal vesicles and claspers compared with those in the Strait of Sicily, suggesting the occurrence of stronger sperm competition at the former site. Similarly, females in the northern Adriatic Sea showed heavier oviducal glands and longer reproductive tracts compared with those in the Strait of Sicily. The coevolution between male and female genitalia suggests the occurrence of stronger sexual conflict and/or cryptic female choice in the population from the northern Adriatic Sea. Therefore, natural selection, represented by the different selective pressures occurring at different latitudes, and sexual selection, represented by potentially differing strengths of post-copulatory sexual selection and sexual conflict, may act individually in driving divergence in life history and reproductive traits in these two populations of S. canicula.

The smooth-hounds represent a significant proportion of the elasmobranch catch in the Adriatic basin of the Mediterranean Sea, where the common (Mustelus mustelus) and blackspotted (Mustelus punctulatus) smooth-hounds co-occur. The 2 species share several morphological and morphometric characters that lead to frequent misidentification. In order to provide information useful for their species identification, we performed a morphological identification of several Mustelus specimens to select individuals unambiguously attributed to 1 of the 2 species, and assayed these with 3 new molecular tests. First, we developed and validated a mitochondrial DNA assay based on species-specific amplification of the cytochrome c oxidase subunit 1 (COI). Second, a fragment analysis of 15 microsatellites cross-amplified from several triakid species was performed to identify diagnostic loci. Finally, a length difference was identified in the internal transcribed spacer 2 (ITS2) region and a diagnostic ...

ABSTRACT The Western Antarctic Peninsula (wAP) is globally one of the systems most heavily impacted by climate change, notably steep declines in sea ice extent. In forage species, reproductive resilience to change is particularly important because population fluctuations are rapidly communicated through the system via trophic interactions. The reproductive traits of the ice-dependent forage species Antarctic silverfish (Pleuragramma antarctica) from different areas along the wAP and at the tip of the Antarctic Peninsula were investigated through macroscopic and histological analyses of gonads, with the aim to assess its reproductive potential and to test for spatial differences in fecundity and spawning season. Fish samples were collected in late summer off Charcot Island, in Marguerite Bay and off Joinville Island; no fish were caught in the central wAP. Samples from Charcot Island and Marguerite Bay consisted of adults in developing gonad stage, whereas those from Joinville consisted almost exclusively of juveniles. Mean GSI was relatively low (2–3%) and similar in both sexes, as specimens were still far from being actively reproducing. Developing females exhibited two discrete, though partially overlapping modes of oocytes of different size, with vitellogenic oocytes measuring 0.5–1.0 mm. Absolute and relative fecundity ranged between 3000 and 12,000 eggs per female and between 80 and 190 eggs·g−1, with a strong relationship between absolute fecundity and body size. These results were consistent with a single population at Charcot Island and Marguerite Bay and indicated substantial reproductive potential, which may mitigate population isolation and reductions in habitat availability but cannot ultimately offset catastrophic loss of spawning habitat linked to sea-ice retreat.

... 1 Department of Biology, University of Padova, Padova, Italy; 2 College of the Atlantic, Bar Harbor, ME, USA. *Correspondence: Authors' addresses: Carlotta Mazzoldi (for correspondence), Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy. ...

ABSTRACT In the field, parental males of the black goby Gobius niger were always >9 cm LT, showed a conspicuous elongation of the first dorsal fin, and were darkly coloured. Larger parental males did not occupy larger nests or obtain more eggs, suggesting that over a threshold size reproductive success was not correlated with male size. The mating system was polygynous with different egg clutches simultaneously present in a nest. Smaller sexually mature males were observed around and inside nests in which spawning was occurring. These opportunistic males ranged in body size between 6 to 8 cm LT. In contrast to parental males, they did not show an exaggeration of the first dorsal fin and were cryptically coloured, thus resembling small females in their external morphology. Aquarium experiments confirmed that smaller males perform a sneaking behaviour, releasing sperm when parental males spawn. As a consequence, it is possible to define three male types: type I are small, without an elongated dorsal fin and adopt a sneaking mating tactic; type III are large, have a pronounced elongation of the dorsal fin and perform parental behaviour; type II are intermediate both in size and elongation of the first dorsal fin and behave as either as sneakers or, possibly, as parental males according to nest availability and male competition.

... Petersen, CW, Mazzoldi, C., Zarrella, KA and Hale, RE (2005), Fertilization mode, sperm characteristics, mate choice and parental care patterns in Artedius ... Oviposition sites were also tagged in the intertidal at Mitchell Bay, San Juan Island (48°34′ N; 123°10′ W) to determine ...

... Antimicrobial egg cleaning by the fringed darter (Perciformes: Percidae: Etheostoma crossopterum): implications of a novel component of parental care in fishes. Proceedings of the Royal Society of London B 270, 2405–2411. ... Innate immunity of fish (overview). ...