Lamprey (Entosphenus sp. and Lampetra sp.) estuarine occupancy is regionally variable and constrained by temperature

Abstract

Temperature and sea level are predicted to rise with climate change, bringing an urgency to evaluating future viability of native fish. Lamprey are confronted with widespread habitat degradation, migratory barriers, and episodes of environmental change projected to be commonplace in the future. In California, range contraction likely shifted lamprey rearing downstream, but the extent and physiological constraints that restrict estuarine rearing are unclear. We used a single-season occupancy model to describe juvenile lamprey estuarine distribution and found occupancy was regionally variable and constrained by temperature. Habitat and hydrology providing thermal refugia may be critical for future persistence. K E Y W O R D Sammocoete, climate change, Entosphenus sp., Lampetra sp., single-season occupancy model, temperature

Space‐for‐time is not necessarily a substitution when monitoring the distribution of pelagic fishes in the San Francisco Bay‐Delta

“…The SKT and EDSM were both initiated with the aim of monitoring the distribution and relative abundance of Delta Smelt to inform policy and management decision making in the Bay-Delta. It is clear that monitoring data collected in the Bay-Delta are complicated by the observation process and that capture efficiency can vary considerably (Goertler et al, 2020;Latour, 2016;Mahardja et al, 2017Mahardja et al, , 2021Mitchell et al, 2017Mitchell et al, , 2019Newman, 2008;Peterson & Barajas, 2018;Polansky et al, 2019;Thomson et al, 2010;this study). Although trends in occupancy and relative abundance of fishes in the raw catch data for a few species and monitoring programs (with different sampling extents and resolutions) in the Bay-Delta appear unbiased when compared to estimates from multistate occupancy models (Peterson & Barajas, 2018), there are at least two primary reasons why not separating the ecological and observation process is problematic with respect to the goals of SKT, EDSM, and management in the Bay-Delta.…”

“…Over the years, additional monitoring programs that rely on trawl surveys have been initiated by different management agencies to monitor fishes for different objectives. Although fish catch data from these surveys have long been used to inform policy and management decision making, it was not until relatively recent that the effect of the observation process on inferences regarding the distribution and relative abundance of fishes in the Bay‐Delta was considered (Goertler et al, 2020; Latour 2016; Mahardja et al, 2017, 2021; Mitchell et al, 2017, 2019; Newman 2008; Peterson & Barajas, 2018; Polansky et al, 2019; Thomson et al, 2010). Overall, this collection of work has demonstrated that fish capture efficiency varies markedly across species, time, location, and monitoring program within the Bay‐Delta.…”

“…Given the above findings, it is clear that the data collected by fish monitoring programs in the Bay-Delta need to be corrected for incomplete capture to properly inform decision making. Like many monitoring programs across the world (Budy et al, 2015;Duarte et al, 2021;Kéry et al, 2010;Sadoti et al, 2013;Van Strien et al, 2013;Whitlock et al, 2020; and many more), occupancy models are increasingly being used to accomplish this for fishes in the Bay-Delta despite sampling designs not explicitly considering occupancy models when many of these monitoring programs were established (Goertler et al, 2020;Mahardja et al, 2017Mahardja et al, , 2021Peterson & Barajas, 2018). However, one of the long-term monitoring programs used to monitor the distribution and relative abundance of Delta Smelt (Hypomesus transpacificus) in the Bay-Delta, the Spring Kodiak Trawl (SKT), lacks temporal replicate surveys (Newman et al, 2017).…”

Lampreys in California (Lampetra spp. and Entosphenus spp.): Mitochondrial phylogenetic analysis reveals previously unrecognized lamprey diversity

“…This suggests that the biogeographic distribution of lamprey diversity may follow the same patterns observed in other native fish taxa. Although the abundance and distribution of lamprey species have not been systematically assessed throughout California, evidence strongly suggests that both range contractions (Goertler et al 2019) and population declines (Moyle et al 2009) have occurred.…”

Sampling Methods and Survey Designs for Larval Lampreys

“…Studies have determined the baseline occupancy and detection probabilities of larval lampreys (Harris et al 2020), evaluated larval use of pools and riffles in small streams (Starcevich and Clements 2013), and determined larval distribution in deepwater habitats (Jolley et al 2012; Harris and Jolley 2017). In addition, Goertler et al (2019) described larval distribution in estuaries, although it is unclear whether their specimens were in fact larvae or juveniles (see Clemens 2019 for life stage terminology). These studies provide information on occupancy and detection probabilities for larval lampreys in a range of habitats, which could be used to guide the selection of survey designs and methods to improve survey efficiency in future studies.…”