Improving macroscopic maturity determination in a pre-spawning flatfish through predictive modeling and whole mount methods

Midway, Stephen R.; White, J. Wilson; Roumillat, William A.; Batsavage, Christopher; Scharf, Frederick S.

doi:10.1016/j.fishres.2013.07.010

Cited by 9 publications

(7 citation statements)

References 35 publications

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“…Microscopic identification is the most accurate method to assign the maturity status of an individual, but it requires trained workers and high financial and time investment. On the other hand, macroscopic identification may display high accuracy as it considers the external morphological features of the gonads linked to the maturation stage, such as size and colour (Midway et al ., 2013; Peer et al ., 2012). Compared to the former, macroscopic identification requires less financial and time investment, but it is biased by individual perception (Hashiguti et al ., 2019) and exhibits high levels of misclassification ( e.g ., Ferreri et al ., 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Compared to the former, macroscopic identification requires less financial and time investment, but it is biased by individual perception (Hashiguti et al ., 2019) and exhibits high levels of misclassification ( e.g ., Ferreri et al ., 2009). Error in the classification of maturity status is primarily associated with classifying individuals in early maturation stages as mature or classifying resting individuals as immature (Midway et al ., 2013; Núñez & Duponchelle, 2009), which may bias L 50 estimates and the establishment of reproductive periods. Sampling should be performed during the main spawning period to avoid such bias (ICES, 2008), which may not be possible for species that spawn continuously, such as R. transfasciatus .…”

Section: Discussionmentioning

confidence: 99%

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Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid

Soares

Barros

Freitas

et al. 2020

Journal of Fish Biology

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Length at first maturity (L 50) is an important tool for the management and conservation of fish populations. Traditional approaches based on macroscopic and microscopic maturity staging exhibit high accuracy and precision, while alternative approaches (e.g., I g-based staging, stanza changing point) are less resource-demanding. Herein, we compare four approaches to estimate L 50 in a population of the heptapterid Rhamdioglanis transfasciatus from Atlantic Forest streams. Fish were sampled monthly during a year by using electrofishing. We measured the length (cm), mass (g), and gonad mass (g) of each specimen, then classified their maturity status macroscopically and microscopically. Alternative approaches were strongly discordant from traditional ones. Logistic curves considering mature individuals as those displaying at least 1% of the maximum I g in the sample greatly underestimated L 50 for females and overestimated L 50 for males. The stanza changing point derived from the polyphasic growth model underestimated L 50 in both cases. Despite the increasing development of less onerous approaches, it seems that they are not suitable for all fish populations and the requirements to use such approaches demand further investigation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid

Soares

Barros

Freitas

et al. 2020

Journal of Fish Biology

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show abstract

“…Building on the work of these authors, a number of additional statistical tests were conducted to produce even more extensive quantitative comparisons between macroscopic and microscopic phasing. Other authors should be encouraged to continue to advance these analyses, and also consider alternative approaches using predictive models to determine maturity status from demographic traits and macroscopic gonad features (Peer et al , ; Midway et al , ).…”

Section: Discussionmentioning

confidence: 99%

Success and failure assessing gonad maturity in sequentially hermaphroditic fishes: comparisons between macroscopic and microscopic methods

Klibansky

Scharf

2015

Journal of Fish Biology

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For two protogynous hermaphrodite fish species, the performance of visual gonad analysis techniques was evaluated to determine when the use of macroscopic methods was sufficient and when microscopic techniques were necessary. Simple macroscopic gonad analysis was found to be a powerful tool for distinguishing sex and whether or not females were spawning capable or ripe for black sea bass Centropristis striata (n = 1443) and red porgy Pagrus pagrus (n = 980), often producing results that were in close agreement with more complex and expensive microscopic techniques. Estimates of key reproductive variables, such as size-dependent sex-change ogives, spawning season duration, spawning fraction and batch number, were also very similar or equal between methods. Apparent seasonal spawning activity was also predicted similarly by each method and the patterns were highly correlated with seasonal patterns in gonado-somatic indices. In contrast, distinguishing between immature females and those that were mature, but inactive, proved difficult when using macroscopic methods and, in these cases, predictions often differed from those produced microscopically. In turn, maturity ogives differed significantly between methods for C. striata (maturity ogives could not be generated for P. pagrus as nearly all fish encountered were mature). Agreement rates among male phases were also very low. Macroscopic methods were able to identify signs of sex transition in very advanced specimens, but early signs were only evident microscopically. While much more detail is visible microscopically, here several population-scale parameters important for fisheries management were estimated equally well with the unaided eye for C. striata and P. pagrus. For comprehensive, fishery-independent surveys and long-term research programmes in particular, determining when microscopic techniques are and are not necessary can greatly improve efficiency and reduce costs without compromising data quality.

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“…Therefore, reliable and cost‐effective alternatives based on macroscopic criteria and routinely collected biological information are needed by management agencies. For instance, Midway, White, Roumillat, Batsavage, and Scharf () achieved up to >90% success rates in predicting the reproductive status of the southern flounder Paralicthys lethostigma by including regularly collected biological information, such as ovarian morphology, sampling dates, and fish length, in predictive models. Similarly, using only morphological measures to discriminate sexually mature individuals from immature juveniles achieved a 72–80% correct classification in the American eel Anguilla rostrata (Cottrill, McKinley, & Van Der Kraak, ).…”

Section: Introductionmentioning

confidence: 99%

Maturity assignment based on histology‐validated macroscopic criteria: Tackling the stock decline of the Mediterranean swordfish (Xiphias gladius)

Marisaldi

Basili

Candelma

et al. 2019

Aquatic Conservation

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Effective stock assessment relies on the evaluation of the reproductive potential of a population, but this is often achieved using fast, inexpensive, and inaccurate macroscopic indicators of gonadal maturity. Indeed, this approach suffers from high error rates as a result of misclassification and operator errors. Although histology is considered the gold standard to assign reproductive stages, it represents a time‐consuming and expensive method. Therefore, cost‐effective approaches are currently needed to assess the species‐specific reproductive potential and define the correct size at first maturity (L50). In the present study a histology‐calibrated method based on the gonadal index (GI) was developed to assign maturity stages to the overfished Mediterranean swordfish (Xiphias gladius), supported by histological classification of gonadal development, an estimation of L50, and an analysis of the reproductive output of this species. The performance of this new method had an overall agreement of 90% with histological data, and the L50 calculated by the GI‐based method compared with histology analysis was not statistically different (p > 0.05). Moreover, in order to apply this method without bias, a thorough validation of the relationship between length and gonad weight was carried out and the suitability of the GI to compare individuals of different size and maturity stages was confirmed. The present findings provide a comprehensive picture of the patterns characterizing Mediterranean swordfish reproduction and a promising method to assign maturity stages based on a macroscopic indicator. This method has the potential to be extensively applied during routine fish sampling activities in the field because of its simple requirements.

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Improving macroscopic maturity determination in a pre-spawning flatfish through predictive modeling and whole mount methods

Cited by 9 publications

References 35 publications

Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid

Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid

Success and failure assessing gonad maturity in sequentially hermaphroditic fishes: comparisons between macroscopic and microscopic methods

Maturity assignment based on histology‐validated macroscopic criteria: Tackling the stock decline of the Mediterranean swordfish (Xiphias gladius)

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Improving macroscopic maturity determination in a pre-spawning flatfish through predictive modeling and whole mount methods

Cited by 9 publications

References 35 publications

Traditional approaches to estimate length at first maturity (L50) retrieve better results than alternative ones in a Neotropical heptapterid

Traditional approaches to estimate length at first maturity (L50) retrieve better results than alternative ones in a Neotropical heptapterid

Success and failure assessing gonad maturity in sequentially hermaphroditic fishes: comparisons between macroscopic and microscopic methods

Maturity assignment based on histology‐validated macroscopic criteria: Tackling the stock decline of the Mediterranean swordfish (Xiphias gladius)

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Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid

Traditional approaches to estimate length at first maturity (L₅₀) retrieve better results than alternative ones in a Neotropical heptapterid