Patterns and consequences of life history diversity in salinity exposure of an estuarine dependent fish

Abstract

While it is common knowledge that Red Drum (Sciaenops ocellatus) inhabit oligohaline waters (salinity <5), lifetime reconstructions of salinity histories have been lacking, and this study provides unique insight into interannual and ontogenetic patterns of oligohaline occupancy by this economically valuable sportfish. Growth consequences of oligohaline exposure and the relationship of oligohaline residency with river discharge were also investigated. Oligohaline exposure varied most during years 2 and 3 of life. During this time, 22% (n = 26/120 individuals) of Red Drum were oligohaline residents (≥ 90% of these years spent in oligohaline salinities), 34% (n = 41) were mesopolyhaline residents (< 10% of years 2 and 3 spent in oligohaline waters), and 44% (n = 53) spent time in both oligohaline and meso-polyhaline salinities. Trends in oligohaline residency match putative Red Drum life history. Oligohaline residents were present during years 1-6 of life; however, oligohaline residency peaked during the second year of life (n = 37, 31%) and by year 7 no oligohaline residents remained. Growth of oligohaline resident Red Drum during years 2-3 of life was lower than non-resident fish. However, long-term growth consequences of oligohaline residency were not apparent. The proportion of oligohaline residents during years 2 or 3 of life was positively related to river discharge. This divergence in salinity residency by juvenile Red Drum demonstrates that life history diversity was present in this population and that oligohaline waters provided important nursery habitat for fish that successfully recruited to the adult population.

Deciphering Eurasian otter (Lutra lutra L.) and seal (Phoca vitulina L.; Halichoerus grypus F.) diet: Metabarcoding tailored for fresh and saltwater fish species

“…Direct removal of fish caught in nets by seals is supposed to be almost nonexistent in the study area as passive fishing with gillnets or long lines is very limited (Döring et al, 2020). Additionally, wildlife tends to feed on fishes of a smaller size than those targeted by fisheries (Houle et al, 2016; Nelson et al, 2021; Tollit et al, 2011).…”

Life history of spinyhead croaker Collichthys lucidus (Sciaenidae) differentiated among populations from Chinese coastal waters

“…Finally, the average of the 12 data points (line length ~ 7 μm) was calculated as the element concentration at this point (Heimbrand et al 2020). This was a conservative approach to remove outliers, and the calculation clearly filtered out erroneous data that were likely a result of instrument noise rather than ecologically relevant values (McMillan et al 2017, Nelson et al 2021. The product between the analysis time and the scanning speed was used to calculate the distance from the otolith core to the edge.…”

Southern Flounder Life History Diversity and Contributions to Fisheries from Differing Estuarine Salinity Zones

“…2005; Rohtla and Vetemaa 2016; Nelson et al. 2021). Regardless of the exact underlying mechanism, differing habitat use can have important implications for growth, mortality, fitness, and vulnerability to fishery exploitation (Secor 1999; Hodge et al.…”

“…This can result from partial migration, in which a population has distinct groups of resident and migratory individuals that use different salinities as a result of migratory or resident behaviors (Secor 1999;Elsdon and Gillanders 2006;Chapman et al 2012). Conversely, a wide diversity of salinity and habitat-use variation can also exist when populations have no identifiable contingent structure but contain individuals that exhibit facultative use of various salinities throughout life (Cucherousset et al 2005; Rohtla and Vetemaa 2016; Nelson et al 2021). Regardless of the exact underlying mechanism, differing habitat use can have important implications for growth, mortality, fitness, and vulnerability to fishery exploitation (Secor 1999;Hodge et al 2014;Gillanders et al 2015).…”