Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management

Abstract

The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/018671 doi: bioRxiv preprint first posted online May. 7, 2015; in the main stem rivers of the Amazon Basin and make up the regions largest fishery.

Unmasking continental natal homing in goliath catfish from the upper Amazon

“…Recent evidence regarding the migration patterns of B. rousseauxii (Hegg, Giarrizzo and Kennedy, 2015;Duponchelle et al, 2016;Hermann et al, 2016; this study) clearly indicate that its exceptional life history, involving the largest known migration in freshwaters (>11,000 km, Barthem et al 2017), is more diverse than previously thought. It will be critical to further characterise the extent of this diversity, which suggests a certain amount of plasticity and adaptability, in order to better anticipate the potential consequences of current and future perturbations, particularly overfishing and hydropower development.…”

“…Reproducing during the receding water period, when the river returns to its natural bed, probably reduces the risk of eggs and larvae being lost in the adjacent floodplains and therefore maximises their chances to reach the estuarine nursery area thousands of km downstream (García-Vasquez et al, 2009). By contrast, breeding during the high-water periods would increase this risk and lost juveniles that survive on the floodplain may become residents, as hypothesised by García-Vasquez et al (2009) (Hegg, Giarrizzo and Kennedy, 2015).…”

“…The existence of variable life histories may indeed increase resilience of species, allowing them to withstand environmental changes (Hegg, Giarrizzo and Kennedy, 2015;Waldman, Wilson, Mather, & Snyder 2016). The literature on anadromous fishes, and salmons in particular, have shown that diversity in life-history strategies and the existence of various source populations provide further protection against decline or extinction in the face of environmental disturbance (Hilborn, Quin, Schindler and Rogers, 2003;Copeland and Venditti, 2009;Beechie, Buhle, Ruckelshaus, Fullerton and Holsinger, 2006, see also Hegg, Giarrizzo and Kennedy, 2015 It will also be important to assess whether the disruption of the seemingly compulsory nursery period in the lower Amazon estuary alters growth and reproductive patterns of resident fish.…”

“…By contrast, strontium (Sr) isotopic ratios in otoliths, which depend almost exclusively on the age and bedrock geological composition of watersheds, and thus barely vary across years, represent accurate habitat signatures in freshwaters (Kennedy, Folt, Blum, & Chamberlain 1997;Kennedy, Blum, Folt, & Nislow 2000;Barnett-Johnson, Pearson, Ramos, Grimes, & MacFarlane 2008). Recently, the use of 87 Sr: 86 Sr has proved effective in determining migratory patterns of freshwater fishes in complex and extensive river systems, such as the Amazon Basin (Pouilly, Point, Sondag, Henry, & Santos 2014;Garcez, Humston, Harbor, & Freitas 2015;Souza, Humston, & Freitas 2016), including in goliath catfishes (Hegg, Giarrizzo, & Kennedy 2015;Duponchelle et al, 2016). Otolith 87 Sr: 86 Sr analyses using laser ablation-multi-collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) have confirmed a >8,000-km migration and revealed natal homing in populations of B. rousseauxii from the largest white-water Amazon River tributary-the Madeira River (Duponchelle et al, 2016; Figure 1).…”

Genetics and telemetry indicate unexpected movements among structured populations for Brachyplatystoma platynemum in the Amazon

“…Ochoa et al () have discussed possible reasons for the high levels of haplotype diversity and the occurrence of two structured populations with high values for F ST in B. platynemum , including climate changes, drainage isolation and differences in water chemistry. Dam construction, with the consequent blockage of migratory routes, may change the natural life cycle of fish species inhabiting the affected area, as well as the usual distribution of populations (Forsberg et al, ; Hegg et al, ). Our analyses indicate a dominance of B. platynemum specimens of Madeira population downriver of the recent dam constructed in the Madeira River and a movement of the Amazon population specimens to Madeira River.…”