Upstream migration of amphidromous gobies of La Réunion Island: implication for management

Borie²,

Blob

et al. 2018

Journal of Zoology

Self Cite

The morphology of an individual can affect functional performance and, ultimately, survival and fitness. To study these links, a first step is to evaluate the relationship between morphology and performance. Sicydiine fishes are an interesting model for such studies, because successful completion of their life cycle depends on a functionally demanding task: climbing waterfalls when they return to freshwater from the ocean. Previous studies identified two different climbing modes among sicydiines: ‘inching’ and ‘powerburst’. Relationships between morphology and climbing performance have been found for inching and powerburst species present on different islands from distant oceans (Pacific and Caribbean), but species from the same island have not been compared. In this study, we challenged two different sicydiine species from Réunion Island to an artificial climbing ramp: the inching climber Sicyopterus lagocephalus and the powerburst climber Cotylopus acutipinnis. For each species, we evaluated differences in morphology between successful and unsuccessful climbers. We predicted that species with similar climbing styles (S. lagocephalus and S. stimpsoni) would show differences between successful and unsuccessful climbers that more closely resembled each other than differences between successful and unsuccessful climbers across species from the same island (S. lagocephalus and C. acutipinnis). This prediction was only partially met. S. lagocephalus individuals with a streamlined body showed better climbing performance, as observed for S. stimpsoni. However, the size of the pelvic sucker, which fish use to attach to the substrate while resting, appeared less important for S. lagocephalus than for S. stimpsoni and C. acutipinnis. Instead, the size of the mouth, which inching species use to attach to the substrate while moving up, seemed important for S. lagocephalus but not for other species. Thus, differences in the morphology–performance relationship among sicydiines may relate not only to differences in climbing mode, but also to species‐specific specializations within each climbing mode.

Section: Discussionmentioning

confidence: 97%

Intra‐ and inter‐specific morphological diversity of amphidromous gobies influences waterfall‐climbing performance

Borie²,

Blob

et al. 2018

Journal of Zoology

Self Cite

“…The hypotheses explaining these displacements are generally related to fish competition for habitat (Fitzsimons & Nishimoto, 1990), extreme climatic events that induce fish flushing (Lagarde et al, 2015;Smith & Kwak, 2014a), or reproduction (Koster et al, 2013;Lord et al, 2011). The hypotheses explaining these displacements are generally related to fish competition for habitat (Fitzsimons & Nishimoto, 1990), extreme climatic events that induce fish flushing (Lagarde et al, 2015;Smith & Kwak, 2014a), or reproduction (Koster et al, 2013;Lord et al, 2011).…”

Section: Moreover the Steep Rivers With High Flow Velocity Of La Réumentioning

confidence: 99%

“…Downstream migration can be related to movement of adult fish towards spawning grounds close to the marine environment. For instance, Lagarde, Teichert, Boussarie, Grondin, and Valade (2015) documented upstream movements of Sicyopterus lagocephalus adults that were probably recolonising their initial habitats after having been washed down during flood events. However, fish movements between river reaches are not exclusively linked to reproduction, but can also be related to foraging behaviour or competition for food and/or territory, or caused by involuntary displacement due to periodic disturbances, such as cyclonic floods .…”

mentioning

confidence: 99%

“…However, fish movements between river reaches are not exclusively linked to reproduction, but can also be related to foraging behaviour or competition for food and/or territory, or caused by involuntary displacement due to periodic disturbances, such as cyclonic floods . For instance, Lagarde, Teichert, Boussarie, Grondin, and Valade (2015) documented upstream movements of Sicyopterus lagocephalus adults that were probably recolonising their initial habitats after having been washed down during flood events. Given the high diversity in movement patterns observed among amphidromous species, insights on the successive habitats crossed by individuals in both marine and freshwater environments are essential to understand populations dynamic and improve conservation efforts.…”

mentioning

confidence: 99%

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Site fidelity and movements of an amphidromous goby revealed by otolith multi‐elemental signatures along a tropical watershed

Teichert

Tabouret

Ecology of Freshwater Fish

et al. 2018

Otolith microchemistry can provide crucial information to address gaps of knowledge in spatio‐temporal ecology of fish species. However, understanding the seasonal variability of water chemistry and its effect on otolith signatures is needed to interpret fish movements. Otolith multi‐elemental signatures were used to examine the diadromous migration and small‐scale movements of a tropical goby (Sicyopterus lagocephalus) within a watershed in La Réunion Island, Indian Ocean. The elemental ratios Sr:Ca, Ba:Ca and Sr:Ba recorded monthly in the water of nine sampling sites varied between localities and were correlated with otolith signatures, whereas the Mg:Ca signature was not. The incorporation of some trace elements in otoliths was influenced by the size of fish and site where they were caught, reflecting an effect of endogenous and exogenous factors. Despite these sources of variation, the elemental signatures did not overlap for three river sections distributed along the 26‐km‐long watershed. The diadromous migration and fish lifetime movements between these river sections were reconstructed using an original process based on random forest analysis. This approach revealed distinct migratory behaviours after fish entered in the river, with some individuals progressing slowly in the watershed whereas other rapidly reached the upper localities. As adults, S. lagocephalus showed a restricted exploratory behaviour and a strong site fidelity to a particular part of the watershed. The detection of adult movement was typically only between adjacent locations and is possibly explained by shifts in local intraspecific hierarchies and/or displacement during extreme discharge caused by cyclones.

“…This hypothesis has been developed by Lord, Tabouret, Claverie, Pécheyran, and Keith (2011) based on the variations in otolith elemental composition in adults of Sicyopterus lagocephalus and S. aiensis in Vanuatu rivers. However, a recent study focused on the migration of adults and juveniles of two Sicydiinae species, including S. lagocephalus, in tropical rivers (Lagarde, Teichert, Boussarie, Grondin, & Valade, 2015), suggested that the downstream displacements of adults depend solely on hydrological disturbances during cyclonic floods. If spawning location is not intended to reduce the time spent by larvae in freshwater, the only strategy for reaching the ocean more rapidly would be that larvae drift faster, mainly during periods of elevated river discharge.…”

mentioning

confidence: 99%

Artificial daily fluctuations of river discharge affect the larval drift and survival of a tropical amphidromous goby

Ecology of Freshwater Fish

Teichert

Faivre³

et al. 2017

Amphidromous fish species reproduce in rivers, and their larvae immediately drift to the sea after hatching. Most of these larvae survive in freshwater for a few days only, rapidly reaching sea water is thus essential. Being of small size, especially among species of the Sicydiinae subfamily, the larvae possess poor swimming abilities; their drift dynamics is considered to be mainly passive and influenced by flow conditions. The influence of daily fluctuations in flow regime on Sicyopterus lagocephalus (Sicydiinae) larval drift patterns was studied using drift nets at three sites along the dammed Langevin River in Reunion Island. The river flow was stable at the upstream site when frequent anthropogenic river flow fluctuations were observed at the two sites downstream to the dam. Weak diel larval drift dynamics were detected at the upstream site and the first site under anthropogenic river flow conditions. In contrast, larval drift dynamics at the most downstream site was strongly influenced by anthropogenic daily fluctuations of discharge: the abundance of drifting larvae increased with peaks of discharge, regardless of the time. As higher mortality rates of drifting larvae were observed during discharge peaks, the benefit of a more rapid travel to the ocean associated with these peaks should be lower than expected. It is concluded that peaks of discharge increase the number of larvae drifting to the sea probably due to higher physical constraints on the egg clutches, but also decrease the chance of survival for larvae that may be nonfully developed. K E Y W O R D Sdiadromy, downstream migration, hydrology, mortality, Sicydiinae, Sicyopterus lagocephalus