Interpopulational variation of the mating system in the peacock blenny Salaria pavo

Saraiva, João L.; Pignolo, Giulia; Gonçalves, David; Oliveira, Rui Filipe

doi:10.1007/s10211-011-0104-y

Cited by 16 publications

(14 citation statements)

References 31 publications

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“…In the artificial conditions provided by human farming activities, it is likely that the most successful phenotypes of farmed animals are different from those under natural conditions. However, that does not mean that these selected phenotypes carry differential genotypes, especially due to phenotypic plasticity which is remarkably relevant in fish: different populations of the same species present contrasting yet plastic behavioural responses to environmental and social conditions [32][33][34][35][36][37][38]. Nevertheless, artificial selection experiments demonstrate that almost any quantitative trait could be permanently altered, that responses (mostly) occurred as a consequence of changes in the frequencies of genes affecting the traits, and not from mutations, and that many genes must be involved [39,40].…”

Section: Genesmentioning

confidence: 99%

Domestication and Welfare in Farmed Fish

Saraiva¹,

Castanheira²,

Arechavala-López³

et al. 2019

Animal Domestication

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The domestication of fish species is still in its early stages when compared to terrestrial animals. The effects of domestication on welfare of farmed fishes are complex to study because fish differ from livestock in genetics, physiology and behaviour, and experience different sensory worlds. Consequently, empathy with fish and understanding of their needs becomes more problematic than with land animals. Additionally, the acknowledgement and study of mental dimensions of fish existence is very recent. We discuss that higher levels of domestication in fish do not necessarily correspond to better welfare because (1) artificial selection by the aquaculture industry is mostly focused on production-related traits such as growth, and this selection process may have unknown negative effects on welfare-related traits; (2) the number of fish species presently farmed (circa 300) is 10-fold higher than land animals, rendering the establishment of standard welfare guidelines extremely complicated; (3) the current paradigm of the Five Freedoms guiding welfare is outdated and was designed for livestock; and (4) there are still severe knowledge gaps in the biology of farmed fishes, especially in welfare-related traits. The implementation of humane farming systems should integrate industry, science and ethics in an open dialogue in order to produce relevant results.

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Section: Genesmentioning

confidence: 99%

Domestication and Welfare in Farmed Fish

Saraiva¹,

Castanheira²,

Arechavala-López³

et al. 2019

Animal Domestication

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“…; Saraiva et al . ). Nest‐holder males are larger and older, and express a suite of secondary sex characters, namely a head crest and an anal gland that produces a sex pheromone (Gonçalves et al .…”

Section: Methodsmentioning

confidence: 97%

“…The S. pavo population studied inhabits the intertidal zone of a coastal lagoon in the south of Portugal. In this population, two reproductive phenotypes are present: nest-holders and sneakers (Gonc ßalves et al 1996;Saraiva et al 2012). Nest-holder males are larger and older, and express a suite of secondary sex characters, namely a head crest and an anal gland that produces a sex pheromone (Gonc ßalves et al 1996;Serrano et al 2008).…”

Section: S T U D Y S P E C I E Smentioning

confidence: 99%

Birth date predicts alternative life‐history pathways in a fish with sequential reproductive tactics

Fagundes¹,

Simões²,

Saraiva

et al. 2015

Functional Ecology

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Summary In species with plastic expression of alternative reproductive tactics (ARTs), individuals of the same sex, usually males, can adopt different reproductive tactics depending on factors such as body size. The ‘birth date hypothesis’ proposes that condition‐dependent expression of ARTs may ultimately depend on birth date, because individuals born at different times of the year may achieve different sizes and express different reproductive tactics accordingly. However, this has rarely been tested. Here, we tested this hypothesis in a fish with ARTs, the peacock blenny (Salaria pavo). A long‐term (6 years) mark–recapture study demonstrated that ARTs in the peacock blenny were sequential and that males may follow at least two alternative life‐history pathways: a nest‐holder pathway, in which males express the nest‐holder tactic from their first breeding season onwards, and a parasitic pathway, where males reproduce on their first breeding season as sneaker males and subsequently as nest‐holders. We have found evidence of a birth date effect on the expression of ARTs in the peacock blenny. Males following the nest‐holder pathway are born earlier and are larger at the first breeding season than males following the parasitic pathway, but they have similar growth curves. The mechanisms underlying a birth date effect are far from clear and might be diverse. We have not found support for a mechanism of body size threshold triggering sexual maturation and subsequent ARTs. A mechanism of tactic determination that is strictly based on timing of first maturation is also unlikely. A proxy of lifetime reproductive success shows crossing (body size associated) fitness curves for the two main life‐history pathways.

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“…In this way, subordinate males may maintain their female-like morphology and reproduce as parasitic males. This might explain why the frequency of parasitic males is higher in populations with a shortage and aggregation of nest sites [60], as these conditions are likely to increase the frequency of subordinate juveniles. 11-KT, most likely secreted by the testicular glands, seems to be responsible for the conversion of the dominance status to the expression of SSC but exactly which neuroendocrine mechanisms promote the development of testicular glands remains a crucial question.…”

Section: Discussionmentioning

confidence: 99%

Social cues in the expression of sequential alternative reproductive tactics in young males of the peacock blenny, Salaria pavo

Fagundes¹,

Simões

Gonçalves

et al. 2012

Physiology & Behavior

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Phenotypic change in response to variation in environmental cues has been widely documented in fish. Transitions in social dominance, in particular, have been shown to induce a rapid switch in reproductive phenotypes in many species. However, this effect has been mainly studied in adults and focused on behavioural transitions. The way social cues constraint the phenotypic development of juveniles remains poorly studied in fish. We tested the importance of social dominance and density in the phenotypic development of juveniles of the peacock blenny Salaria pavo. This species shows sequential male alternative reproductive tactics. In the first breeding season males can reproduce as nest-holders or as parasitic males (female-mimicking), or postpone reproduction; from the following season afterwards all males reproduce as nest-holders. Parasitic males have relatively larger testes that lack a testicular gland, present in the testes of nest-holders. The testicular gland is the main source of androgens in the testes and accordingly nest-holders have higher circulating androgen levels. In addition, exogenous androgen administration to parasitic males promotes the development of secondary sexual characters (SSC) only present in nest-holders such as a head crest and an anal gland. We raised juveniles under a high or low-density treatment and monitored social interactions for 1 month. No significant effect of density on the development of juvenile males was detected. However, within each replicate, the relative body size of juvenile males at the beginning of the experiment determined their dominance status, with dominant males developing towards the nest-holder morphotype. Dominant males engaged in more nest defence behaviour, showed larger testicular glands, had higher levels of 11-ketotestosterone (11-KT) and testosterone (T) and developed more SSC, as compared to subordinate males. However, these effects of social dominance were moderated by body condition as only dominant males in good body condition developed SSC. The effect of social dominance and of the area of the testicular gland on the development of SSC was mediated by 11-KT and on the expression of nest defence behaviour by T. Interestingly, in spite of the higher androgen levels and more pronounced morphologic development of SSC in dominant individuals, gonadal development was independent of social dominance and most fish still had underdeveloped testis at the end of the experiment. In conclusion, social dominance promoted the development of the testicular gland, an increase in circulating androgen levels and the development of SSC, but did not promote testicular development. This suggests a dissociation of mechanisms underlying sexual maturation and the expression of male reproductive traits. This dissociation seems to be the key for the occurrence of female-mimicking males in this species, which are sexually mature despite lacking the SSC typical of nest-holders.

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Interpopulational variation of the mating system in the peacock blenny Salaria pavo

Cited by 16 publications

References 31 publications

Domestication and Welfare in Farmed Fish

Domestication and Welfare in Farmed Fish

Birth date predicts alternative life‐history pathways in a fish with sequential reproductive tactics

Social cues in the expression of sequential alternative reproductive tactics in young males of the peacock blenny, Salaria pavo

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