Recruitment Sources of Channel and Blue Catfishes Inhabiting the Middle Mississippi River

Abstract

Insight into environments that contribute recruits to adult fish stocks in riverine systems is vital for effective population management and conservation. Catfish are an important recreational species in the Mississippi River and are commercially harvested. However, contributions of main channel and tributary habitats to catfish recruitment in large rivers are unknown. Stable isotope and trace elemental signatures in otoliths are useful for determining environmental history of fishes in a variety of aquatic systems, including the Mississippi River. The objectives of this study were to identify the principal natal environments of channel catfish Ictalurus punctatus and blue catfish I. furcatus in the middle Mississippi River (MMR) using otolith stable oxygen isotopic composition (δ 18 O) and strontium:calcium ratios (Sr:Ca). Catfishes were sampled during July-October 2013-2014 and lapilli otoliths were analyzed for δ 18 O and Sr:Ca. Water samples from the MMR and tributaries were collected seasonally from 2006-2014 to characterize sitespecific signatures. Persistent differences in water δ 18 O and Sr:Ca among the MMR and tributaries (including the upper Mississippi, Illinois, and Missouri rivers as well as smaller tributaries) were evident, enabling identification of natal environment for individual fish. Blue and channel catfish stocks in the MMR primarily recruited from the large rivers (Missouri and Mississippi) in our study area, with minimal contributions from smaller tributaries. Recruitment and year class strength investigations and efforts to enhance spawning and nursery habitats should be focused in the large rivers with less emphasis in smaller tributaries.

Age‐0 blue catfish habitat use and population demographics in the middle Mississippi River

“…These variations in habitat use between the upper Mississippi and the MMR may be due to the pooled nature of the upper Mississippi River, where locks and dams have altered discharge regimes and the distribution of desirable mesohabitats by influencing the large‐scale river features (Phelps et al., ). Laughlin, Whitledge, Oliver and Rude () studying recruitment sources of Mississippi River blue catfish documented that the majority of recruits originated within the Mississippi and Missouri rivers rather than tributaries, further illustrating the importance of main channel habitats.…”

Recruitment sources and spatial patterns of population demographics of spotted bass in a large river–tributary network

“…Understanding patterns of movement and habitat use by fishes to fulfil life‐history requirements (including movement between rivers and tributaries) is key for assessing population dynamics and effects of riverscape fragmentation and for conservation of habitats that contribute to population persistence (Fausch, Torgersen, Baxter & Li, ; Schlosser, ). Furthermore, knowledge of spatial patterns in population demographics and fish movement and dispersal patterns in river–tributary networks is important for identifying relevant spatial scales for population assessment and management (Cooke et al., ; Laughlin, Whitledge, Oliver & Rude, ; Porreca et al., ). In many large rivers, channel geomorphology and hydrology have been severely altered through anthropogenic activities such as impoundments, channelisation and bank stabilisation (Nilsson, Reidy, Dynesius & Revenga, ), which has led to global declines in many riverine fish species (Rinne, Hughes & Calamusso, ).…”

“…Tributaries may be particularly important as recruitment sources for fishes and sustaining species richness in large, mainstem rivers through fish movement from tributary to main‐stem habitats (Pracheil, McIntyre & Lyons, ; Pracheil, Pegg & Mestl, ). Although tributaries can contribute substantially to recruitment of riverine fish stocks, the extent to which early life‐stage dispersal and movement of older juvenile and adult fishes result in exchange of individuals among main‐stem river and tributary habitats can vary considerably among river–tributary networks and species (Benjamin, Wetzel, Martens, Larsen & Connolly, ; Humston, Priest, Hamilton & Bugas, ; Humston et al., ; Laughlin et al., ; Pracheil et al., ; Sousa, Humston & Freitas, ; Spurgeon, Pegg & Halden, ). Thus, additional studies investigating the exchange of fishes among tributary and main‐stem environments across river systems and among fish species are needed to broaden understanding of the influence of river–tributary connectivity on fish population dynamics and to inform spatially explicit assessment and management of fish populations tailored to particular species and systems.…”

“…Elemental analysis of calcified structures has demonstrated utility as a tool for reconstructing fish environmental history where geologic variation provides persistent spatial differences in water chemistry (Pracheil, Hogan, Lyons & McIntyre, 2014), including large rivers and their tributaries in the Midwestern USA (Laughlin et al, 2016;Smith & Whitledge, 2010). Concentrations of some chemical elements in calcified structures reflect elemental concentrations in the waters in which a fish lives (Pracheil et al, 2014).…”

Spatial and Temporal Distinction of Microelemental Signatures of Missouri River Tributaries

“…Laughlin et al . () found that differences in δ 18 O and Sr:Ca persisted over an 8‐year period in the Middle Missouri River, USA. If isotope signatures are more constant than microelemental signatures, then they may provide some advantage in tracing life history of fishes or could be used in conjunction with those microelemental signatures.…”