Estimating size at first maturity (L50) from Gonadossomatic Index (GSI) data

Fontoura, Nelson Ferreira; Braun, Aloisio Sirangelo; Milani, Paulo César Carvalho

doi:10.1590/s1679-62252009000200013

Cited by 71 publications

(64 citation statements)

References 8 publications

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“…When L 50 was estimated by using relative frequency of reproductive animals identified through testes or ovarian morphology, the values was 12.5 cm for males (R² = 0.89; p = 0.02) and 13.0 cm for females (R² = 0.97; p = 0.004). By using the G SI method proposed by Fontoura et al (2009), L 50 was estimated as 13.1 cm for males (R² = 0.95; p = 0.003) and 13.7 cm for females (R² = 0.95; p = 0.002). For males, values of L 50 and the stanza changing length (L sc ) were not different taking into account the 95% confidence interval (Table 2), although this was not the case for females, with estimates of L sc 0.5 to 1.0 cm below the estimates of L 50 . )…”

Section: Resultsmentioning

confidence: 99%

“…The other method, the G SI values were transformed into a percentage of the maximum value recorded for the species. As proposed by Fontoura et al (2009) ; where P = the proportion of reproductive/ adult individuals for each size class; A = the asymptote of the curve; r = rate of change between the non-reproductive and the reproductive phase; L t = total length (cm), and L 50 = size at fist sexual maturity, the estimated size (cm) at which 50% of the individuals have reached maturity. In the approach based on the scale of maturity, A = 1.0.…”

Section: Data Analysesmentioning

confidence: 99%

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Predicting size at first sexual maturity from length/weight relationship: a case study with an Amazonian catfish

Freitas

Almeida²,

Montag

et al. 2016

Neotrop. ichthyol.

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Relationship between length and weight (LWR) is used to describe aspects concerning the life cycle of fish, but does not considers possible changes during the lifetime mainly due to the sexual maturation. Thus, this study aims to identify the size at first maturity of Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) and infer if the reproductive engagement could change growth pattern, concerning the LWR. Estimates of the size at first maturity (L 50 ) were made by visual identification of gonadal development and through the gonadosomatic index (G SI ). L 50 was estimated as 12.5 cm for males and 13.0 cm for females when applied visual identification of gonads development. L 50 estimates increased to 13.05 cm for males and 13.7 cm for females when estimated from G SI values. LWR was adjusted by using a regular power function and through the polyphasic growth model, with proportionality and allometric coefficients changing in a two phases. The results indicate differences in the growth pattern concerning males and females, as well as polyphasic growth. The change in the growth pattern of the polyphasic LWR was estimated at 11.42 cm for males and 12.53 cm for females, suggesting that changes in the growth pattern can sign-out the attainment maturity in this catfish.O estudo da relação entre peso e comprimento é usado para investigar muitos aspectos do ciclo de vida dos peixes, mas não considera que o padrão de crescimento pode mudar durante o tempo vida, principalmente devido à maturação sexual. Desta forma, este estudo objetivou identificar o tamanho de primeira maturação do bagre Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) e testar se início do engajamento reprodutivo pode ser responsável por mudanças no padrão de crescimento da espécie, concernindo à relação peso/comprimento. Estimativas de tamanho de primeira maturação sexual (L 50 ) foram realizadas por meio da identificação visual dos estágios de maturação e pelos valores do Índice Gonadossomático (IGS). O L 50 foi estimado em 12,5 cm para machos e 13,0 cm para fêmeas quando aplicados a identificação visual dos estágios de maturação. A estimativa do L 50 aumentou para 13,05 cm para machos e 13,7 cm para fêmeas quando aplicados os valores de IGS. A relação peso/comprimento foi ajustada utilizando uma função potência e pelo modelo de crescimento polifásico, com coeficientes de proporcionalidade e alométrico diferentes para duas fases. Os resultados indicam diferenças no padrão de crescimento de machos e fêmeas, além de um crescimento polifásico para ambos os sexos. A mudança no padrão de crescimento foi estimada em 11,42 cm para machos e 12,53 cm para fêmeas, sugerindo que essas mudanças podem estar associadas ao início da vida reprodutiva desse bagre.

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Section: Resultsmentioning

confidence: 99%

Section: Data Analysesmentioning

confidence: 99%

Predicting size at first sexual maturity from length/weight relationship: a case study with an Amazonian catfish

Freitas

Almeida²,

Montag

et al. 2016

Neotrop. ichthyol.

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show abstract

“…Female histological classification of size at maturity was performed using standardized ovarian development classifications (Wallace and Selman 1981), with reproductive maturity assigned to individuals with vitellogenic oocytes, post ovulatory oocytes, or hydrated eggs, because these are signs of spawning activity. Size at maturity was assessed using GSI by classifying maturity using 5, 10, 15, and 20% of the maximum GSI as cutoffs for maturity (Fontoura et al 2009). GSI and histological assessment of size at maturity (L 50 ) were determined as the size at which 50% of individuals were mature for a given fork length (FL: length of the fish from the tip of the snout to the fork or middle of the tail) or age (Lowerre-Barbieri et al 2009).…”

Section: Size At Maturity and Spawning Season Assessmentsmentioning

confidence: 99%

The codevelopment of coastal fisheries monitoring methods to support local management

Schemmel

Friedlander

Andrade

et al. 2016

E&S

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ABSTRACT. Small-scale fisheries across the globe provide critical food security, livelihoods, and human well-being, but are threatened by a combination of local and global stressors, including overexploitation, pollution, and climate change. Participatory approaches to management, especially those that incorporate local communities and customary knowledge can provide meaningful biological information that supports sustainable fisheries management and builds local adaptive capacity to changing ocean conditions. Through a collaboration between fishers, scientists, NGOs, and regulating agencies, we developed a low-cost, low-tech method to assess the seasonal spawning peaks, lunar spawning cycles, and size at maturity (L 50 ) for key targeted reef fish, combining traditional knowledge and practice with modern scientific approaches, including gonadosomatic index (GSI) and histology. Two years of community-based monitoring resulted in data from 57 species and 15 families of reef and nearshore fishes (n = 2595), with detailed information for 10 species at 4 locations across the Hawaiian Islands. Comparisons between community-collected GSI data and scientifically (histologically) assessed spawning cycles and size at reproductive maturity produced similar results suggesting that these approaches can be applied in data-poor fisheries to assess spawning seasons and size at maturity (L 50 ), both of which are critical needs for effective fisheries management. Semistructured surveys revealed a large body of local knowledge on spawning times and harvest practices based on allowing spawning to occur before harvesting and protecting small and large size classes, but little evidence that fishers understand temporal patterns of spawning. This suggests that monitoring methods that fill key gaps such as this and are congruent with these local knowledge systems and customary harvest practices may be key for local stewardship and adaptive management.

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“…In the present study, we aimed to estimate the length at first maturity (L 50 ) according to the Gonadossomatic Index (GSI) using a mathematical approach (Marques et al, 2007;Fontoura et al, 2009) and identify if a polyphasic growth pattern is present for C. paleatus, verifying a possible relationship between the stanza changing length and aspects of the fish biology, as the attainment of sexual maturity.…”

Section: Palavras-chavementioning

confidence: 99%

Polyphasic growth in fish: a case study with Corydoras paleatus (Siluriformes, Callichthyidae)

Barradas

Lermen²,

Larre

et al. 2016

Iheringia, Sér. Zool.

Self Cite

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]; where W is the expected weight for a specifi c length L, a 1 and a 2 are the proportionality coeffi cients for stanzas 1 and 2, b 1 and b 2 are the allometric coeffi cients for stanzas 1 and 2, R sc is the stanza changing rate for the switch function and SCP is the stanza changing point for the switch function. The stanza changing point was estimated as 5.28 cm, corresponding with the length at fi rst maturity for this species L mat (5.29 cm). Our data suggest that a complex growth pattern can be in nature, and perhaps not often identifi ed because trends are obscured by natural variability.KEYWORDS. Allometric growth, length at fi rst maturity, reproduction, sexual maturity, length-weight relationship.RESUMO. Crescimento polifásico em peixes: estudo de caso com Corydoras paleatus (Siluriformes, Callichthyidae). Foi estabelecida uma relação peso-comprimento para Corydoras paleatus (Jenyns, 1842) (Siluriformes, Callichthyidae) (n = 596) a partir de amostras obtidas em novembro-dezembro de 2009 e março-abril de 2010, na lagoa da Pinguela (29°46'57"S; 50°11'16"W), Rio Grande do Sul, Brasil. A espécie apresentou um padrão de crescimento alométrico polifásico, cada estágio descrito por uma equação de potência independente e controladas por uma função de interruptora:; onde W é o peso esperado para um comprimento L, a 1 e a 2 são os coefi cientes de proporcionalidade para as fases 1 e 2, b 1 e b 2 são os coefi cientes alométricos para as fases 1 e 2, R sc é a taxa de mudança de fase e SCP é o ponto de mudança de fase. O ponto de mudança fase foi estimado em 5,28 cm, correspondendo com o comprimento de primeira maturação desta espécie (L mat ) (5,29 cm). Nossos dados sugerem que um padrão de crescimento complexo pode ser frequente na natureza, e que talvez muitas vezes não seja identifi cado porque as tendências são obscurecidas pela variabilidade natural. PALAVRAS-CHAVE.Crescimento alométrico, tamanho de primeira maturação, reprodução, maturação sexual, relação peso-comprimento.The weight-length relationship (WLR) is considered frequently as "second class" science (Froese, 2006), and just regular task for any fi shery biologist. Research about WLR are frequently published only as short-communication for species that this information is not yet known (Froese, 2006). As a result, specifi c work on weight and length do not stand out, restricting knowledge of the WLR to a very small number of species (Kulbicki et al., 2005).Of course, it's easy to understand the need of WLR for commercial fi shery, when we need to convert both measurements as an ordinary task. However, the parameters of the WLR, as the proportionality coeffi cient (a) and the allometric coeffi cient (b) could inform several aspects of the fi sh biology, as the general growth pattern or seasonal changes in the fi sh condition (Froese, 2006). The amount of information that could be inferred using this general approach makes it very useful the understand ecological patterns, even for small and not commercial fi sh species. Froese et al. (2014) made a rece...

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Estimating size at first maturity (L50) from Gonadossomatic Index (GSI) data

Cited by 71 publications

References 8 publications

Predicting size at first sexual maturity from length/weight relationship: a case study with an Amazonian catfish

Predicting size at first sexual maturity from length/weight relationship: a case study with an Amazonian catfish

The codevelopment of coastal fisheries monitoring methods to support local management

Polyphasic growth in fish: a case study with Corydoras paleatus (Siluriformes, Callichthyidae)

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