Otoliths (ear stones) of the inner ears of teleost fishes, which develop independently from the skeleton and are functionally associated with hearing and the sense of equilibrium, have significantly ...contributed to contemporary understanding of teleost fish systematics and evolutionary diversity. The sagittal otolith is of particular interest, since it often possesses distinctive morphological features that differ significantly among species, and have been shown to be species- and genus-specific, making it an informative taxonomic tool for ichthyologists. The otolith morphology of the Caspian Sea gobiids has not been thoroughly studied yet, with data available for only a few species. The aim of the present paper is to examine the qualitative and quantitative taxonomic and phylogenetic information in the sagittal otoliths of these species. A total of 118 otoliths representing 30 gobiid species (including 53.5% of the Caspian gobiofauna) in three gobiid lineages (i.e., Gobius, Pomatoschistus, and Acanthogobius) and 11 genera (i.e., all Ponto-Caspian gobiid genera except Babka) were analysed at taxonomic levels using an integrated descriptive and morphometric approach. The results indicated high taxonomic efficiency of otolith morphology and morphometry at taxonomic levels for the Ponto-Caspian gobiids. Our qualitative and quantitative otolith data also (i) support the monophyly of neogobiin gobies, (ii) along with other morphological and ecological data, offer a new perspective on the systematics of Neogobius bathybius, (iii) suggest the reassignment of Hyrcanogobius bergi to the genus Knipowitschia, and (iv) question the phylogenetic integrity of the four phenotypic groups previously defined in the tadpole-goby genus Benthophilus; however, more studies are needed to complete these evaluations and confirm our otolith study findings.
In connection with the expansion of alien gobies in European waters, a question arises whether this process can be enhanced or inhibited by global warming. The gobies are of Ponto‐Caspian origin, ...where the climate is warmer than in invaded European areas. Therefore, they are likely to cope physiologically with climate warming better than native species. Our aim was to identify differences in metabolic traits under elevated summer temperature between the invasive gobies and their native counterparts.
Using a laboratory respirometer, we compared the effect of elevated summer temperature (25 vs. 17°C) on the metabolic responses of fish in two species pairs consisting of an invasive goby versus its native counterpart from the same ecological guild: the invasive racer goby Babka gymnotrachelus versus native European bullhead Cottus gobio, and the invasive monkey goby Neogobius fluviatilis versus native gudgeon Gobio gobio. The paired species share functional traits, including morphological characteristics, despite belonging to different fish families. After 4 weeks of acclimation, standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS = MMR–SMR) of the fish were determined.
We found that SMR increased under elevated temperature irrespective of species, yet it was always lower in the gobies than in natives. The MMR of the racer goby was lower than that of the bullhead across all temperatures, whereas no differences in MMR were found between the gudgeon and monkey goby. On the one hand, the elevated temperature did not affect the AS of the racer goby and bullhead. However, the AS of the racer goby was consistently lower than that of the bullhead across all temperatures. On the other, elevated temperature caused a decrease in AS in both the monkey goby and gudgeon. However, this temperature‐induced change in AS was higher in the gudgeon than in the monkey goby.
In terms of AS, the invaders did not always outperform the natives at higher temperatures. However, the invaders had lower living costs by maintaining a lower SMR. These results suggest that invasion by gobies may be facilitated by global warming, which is likely to increase their occurrence and effect on local fish communities in freshwater temperate systems.
Sulawesi is an island famous for its biodiversity, including many endemic species. In particular, Sulawesi has the highest number of gobies in the world, including species with potential as food ...and/or ornamental fishes. The exploration of freshwater ichthyofauna is important in the context of Indonesian and global biodiversity. This research aimed to identify gobies found in the Luwuk Banggai area of Central Sulawesi, as a contribution to the exploration of Indonesian ichthyofaunal biodiversity. Gobies were sampled from January to March 2019 in the Biak and Koyoan Rivers. The sampled fish were measured and identified based on morphological characteristics. A total of 52 specimens were collected, and identified as belonging to 17 species within two families, the Gobiidae and Eleotridae. Gobies from the Koyoan River comprised 32 specimens from 8 species, while 20 specimens belonging to species were found in the Biak River. Only two species were found in both rivers: Stiphodon semoni and Sicyopterus lagocephalus. These results augment the body of knowledge regarding the presence and distribution of gobies in Indonesia
The burrowing goby Trypauchen vagina has been reported from Brazil for the first time. This goby occurs naturally in the Indo‐Pacific region, where it is typically found burrowed in the bottom ...substrata of marine or brackish waters. Given its rapid development, extended longevity and multiple spawning cycles, the species is represented by large populations in Asian countries. The authors discuss the occurrence of this species in Brazilian waters and conclude that it was introduced via the ballast water of vessels arriving from Asia. They also compare this exotic taxon with the native Brazilian gobies, including Akko dionaea, Microdesmus and Gobioides, that have burrowing habits.
Gut content analyses have found that round gobies (Neogobius melanostomus) are highly dependent on dreissenid mussels but stable isotope analysis has often suggested that the dreissenid contribution ...is lower. However, estimation of dietary contributions with stable isotopes relies on accurate discrimination factors (fractionation factors). To test if discrimination values commonly used in aquatic food web studies are suitable for round gobies, we collected round gobies from Oneida Lake, raised them for 63 days under four different diets (Chironomus plumosus, Mytilus chilensis, Dreissenia spp., Euphausia superba) and measured the change in white muscle δ13C and δ15N. Gobies were also collected throughout Oneida Lake for gut content and stable isotope analysis. Diets changed as round gobies grew, with small round gobies (17-42mm) feeding mostly on cladocera and chironomids, intermediate sized gobies (43-94mm) transitioning from chironomid to dreissenid consumption, and larger gobies (95-120mm) predominantly consuming dreissenids, similar to findings in other studies. Discrimination factors were obtained by fitting a commonly used asymptotic regression equation describing changes in fish δ13C and δ15N as a function of time and diet stable isotope ratios. The discrimination factor determined for δ13C (-0.4‰ ± 0.32, SE) was lower than the "standard" value of 0.4‰, while that of δ15N (4.0‰ ± 0.32, SE) was higher than the standard value of 3.4‰. Turnover rates for both δ13C and δ15N were estimated as 0.02 ‰*day-1. The use of experimentally determined discrimination factors rather than "standard" values resulted in model estimates that agree more closely with the observed increasing importance of dreissenids in gut content of larger gobies. Our results suggest that the importance of dreissenid mussels inferred from stable isotope studies may be underestimated when using standard isotopic discrimination values.
With the onset and increasing frequency of multiple disturbances, the recovery potential of critical ecosystem-building species and their mutual symbionts is threatened. Similar effects to both hosts ...and their symbionts following disturbances have been assumed. However, we report unequal declines between hosts and symbionts throughout multiple climate-driven disturbances in reef-building Acropora corals and cryptobenthic coral-dwelling Gobiodon gobies. Communities were surveyed before and after consecutive cyclones (2014, 2015) and heatwaves (2016, 2017). After cyclones, coral diameter and goby group size (i.e., the number of gobies within each coral) decreased similarly by 28-30%. After heatwave-induced bleaching, coral diameter decreased substantially (47%) and gobies mostly inhabited corals singly. Despite several coral species persisting after bleaching, all goby species declined, leaving 78% of corals uninhabited. These findings suggest that gobies, which are important mutual symbionts for corals, are unable to cope with consecutive disturbances. This disproportionate decline could lead to ecosystem-level disruptions through loss of key symbiont services to corals.
Gobiidae is the most specious fish family in the world with almost 2000 species, however only 11% of them have been described for their larval stages. The entire life cycle information is essential ...to understand the biology and ecology of this important fish group. Previous studies on zooplankton samples from Ensenada de La Paz, Mexico, have shown the presence of several Gobiidae larvae and juveniles which were identified as Evermania zosterura. The main objective of this work was to describe the larval stages of this species, widely distributed in the Eastern tropical Pacific. Our conclusion is that the most useful characters to distinguish this species early-larval stages from those of similar species in the area, are the number of myomeres, the large melanophores (approximately uniformly in size) on the post anal ventral margin, and the elongate internal pigment under the notochord, anterior to the gas bladder.Original Abstract: La familia Gobiidae es la mas diversa de los peces en el mundo con casi 2000 especies, sin embargo solo el 11% de ellos han sido descritos en sus estadios larvarios. El conocimiento del ciclo de vida completo es esencial para entender la biologia y ecologia de este importante grupo de peces. Muestras de zooplancton obtenidas de la Ensenada de La Paz, Mexico, mostraron la presencia de varias larvas y juveniles de Gobiidae, las cuales fueron identificadas como Evermania zosterura. El principal objetivo de este trabajo fue describir los estadios larvarios de esta especie ampliamente distribuida en el Pacifico tropical Oriental. Se describio el desarrollo larvario de E. zosterura con base en 66 especimenes recolectados en la Ensenada de La Paz, Mexico. Solo 53 especimenes se usaron para describir la morfometria y el patron de pigmentacion, mientras que 13 ejemplares transparentados y tenidos se utilizaron para obtener las caracteristicas meristicas. Los especimenes transparentados tuvieron de 30 a 31 vertebras totales; los elementos de las aletas dorsales fueron IV; I, 13-14, los de la aleta anal 1, 13-14 y la mayoria tuvo una formula pterigioforica de 4-111100. La combinacion de estas caracteristicas, confirmo que pertenecen a E. zosterura. El patron de pigmentacion es muy similar a lo largo del desarrollo. Las larvas se caracterizan por tener de tres a cinco melanoforos de tipo dendritico sobre el borde ventral post-anal, de cuatro a nueve melanoforos mas pequenos sobre el borde ventral pre-anal, entre el istmo y el ano, otro melanoforo se presenta a la mitad del margen dorsal de la cola. Hay una pequena mancha de pigmento en el angulo de la maxila y otra en la punta del labio inferior. Hay un pigmento interno alargado por debajo de la notocorda, entre la cabeza y la vejiga natatoria. La flexion de la notocorda se inicia a los 3.5mm BL y termina a los 4.6mm BL; la transformacion al estadio juvenil es cercana a los 13.6mm BL. Nuestra conclusion es que los caracteres mas importantes para distinguir las larvas de esta especie de aquellas similares en el area son el numero de miomeros, los melanoforos grandes (aproximadamente iguales en tamano) en el margen ventral post-anal y el pigmento intemo alargado debajo de la notocorda, anterior a la vejiga gaseosa.
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