Fish reproductive biology plays an important role for fishery management, especially in developing countries. The aim of this study was to compile all available information and analyze reproduction patterns of marine fishes in three Large Marine Ecosystems (LMEs): North, East, and South Brazil Shelves. We tested the hypothesis that the onset and duration of spawning season differ among these three LMEs; compared the ratio between length at first maturity and asymptotic length with the global trend observed; analyzed sex ratios; and tested whether females allocate more energy into reproduction than males. The following data were compiled from published sources and "gray" literature: sex ratio, spawning season, gonadosomatic indices (GSI), and length at first maturity (L m ). The reproductive load was estimated as L m /L ∞ . The median extension of the spawning season in the North, East, and South Brazil Shelves were 6.5, 6.0, and 5.0 months, respectively, with higher frequency during austral summer in South Brazil. Marine fishes from these three LMEs can be grouped in summer and non-summer spawners. About 96% of the cases the reproductive load was between 0.3 and 0.8, which is slightly shifted toward smaller values, compared with the global range of 0.4-0.9. Gonadosomatic indices for females were higher. Contrary to some expectations, there is seasonality in the reproduction of tropical fishes. However, seasonality is stronger in southern populations. Size at first maturity is not efficiently used as a tool for fisheries management in the ecosystems analyzed.
Duas espécies de Mytella ocorrem no estado de Sergipe, M. charruana e M. bicolor, sendo ambas explotadas, porém em proporção desconhecida. Um dos primeiros passos para se avaliar corretamente a importância de cada uma das espécies na economia local é avaliar o rendimento em carne. Assim, o presente trabalho foi concebido com o objetivo de avaliar o rendimento em carne e ao mesmo tempo as relações morfométricas de ambas as espécies. Foram coletadas amostras mensais de aproximadamente 2 kg para cada espécie nos meses de abril a junho de 2014. As relações entre a largura (LC) e o comprimento (CC) da concha estimadas para M. charruana e M. bicolor foram LC = 0,3391 CC + 3,7965 e LC = 0,3934 CC + 5,1308, respectivamente. As relações entre a altura (AC) e o comprimento (CC) da concha foram AC = 0,3546 CC – 1,9146 e AC = 0,2977 CC + 1,1267, respectivamente. Finalmente, as relações entre o peso total (PT) e o comprimento da concha (CC) foram PT = 0,0004 CC2,3976 e PT = 8E-05 CC2,8437, respectivamente. Em todos os casos, foi observada uma diferença estatisticamente significante na relação para ambas as espécies, havendo no geral uma alometria negativa. O rendimento médio de carne in natura para M. charruana e M. bicolor foi de 50,3 e 33,2%, respectivamente. Dessa forma, para obter um quilo de carne (catado) seria preciso coletar aproximadamente 2 kg de indivíduos inteiros (carne e concha) de M. charruana e 3 kg de M. bicolor.
Paralonchurus brasiliensis is one of the most common fish species found in the bycatch of shrimp trawling in Sergipe. We analyzed its population structure through four sampling programs, two using hired shrimp
The global COVID-19 pandemic resulted in many jurisdictions implementing orders restricting the movements of people to inhibit virus transmission, with recreational angling often either not permitted or access to fisheries and/or related infrastructure being prevented. Following the lifting of restrictions, initial angler surveys and licence sales suggested increased participation and effort, and altered angler demographics, but with evidence remaining limited. Here, we overcome this evidence gap by identifying temporal changes in angling interest, licence sales, and angling effort in world regions by comparing data in the ‘pre-pandemic’ (up to and including 2019); ‘acute pandemic’ (2020) and ‘COVID-acclimated’ (2021) periods. We then identified how changes can inform the development of more resilient and sustainable recreational fisheries. Interest in angling (measured here as angling-related internet search term volumes) increased substantially in all regions during 2020. Patterns in licence sales revealed marked increases in some countries during 2020 but not in others. Where licence sales increased, this was rarely sustained in 2021; where there were declines, these related to fewer tourist anglers due to movement restrictions. Data from most countries indicated a younger demographic of people who participated in angling in 2020, including in urban areas, but this was not sustained in 2021. These short-lived changes in recreational angling indicate efforts to retain younger anglers could increase overall participation levels, where efforts can target education in appropriate angling practices and create more urban angling opportunities. These efforts would then provide recreational fisheries with greater resilience to cope with future global crises, including facilitating the ability of people to access angling opportunities during periods of high societal stress.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.