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Matthew J. O’Donnell

Publications and source records attributed to Matthew J. O’Donnell.

5 recordsLinked to original sources

How repeatable is CTmax within individual brook trout over short- and long-time intervals?

As stream temperatures increase due to factors such as heated runoff from impervious surfaces, deforestation, and climate change, fish species adapted to cold water streams are forced to move to more suitable habitat, acclimate or adapt to increased thermal regimes, or die. To estimate the potential for adaptation, a (within individual) repeatable metric of thermal tolerance is imperative. Critical thermal maximum (CTmax) is a dynamic test that is widely used to measure thermal tolerance across many taxa and has been used in fishes for decades, but its repeatability in most species is unknown. CTmax tests increase water temperature steadily over time until loss of equilibrium (LOE) is achieved. To determine if CTmax is a consistent metric within individual fish, we measured CTmax on the same lab-held individually-marked adult brook trout Salvelinus fontinalis at three different times (August & September 2016, September 2017). We found that CTmax is a repeatable trait (Repeatability ± S.E.: 0.48 ± 0.14). CTmax of individuals males was consistent over time, but the CTmax of females increased slightly over time. This result indicates that CTmax is a robust, repeatable estimate of thermal tolerance in a cold-water adapted fish.

Journal of Thermal Biology

Survival and density of a dominant fish species across a gradient of urbanization in North Carolina tidal creeks

Development in the southeastern U.S. coastal plain generates the need for a better understanding of how demographics (survival and abundance) of estuarine nekton respond to urbanization. Apparent survival and density of the dominant Atlantic coast salt marsh fish, Fundulus heteroclitus, were estimated in four North Carolina tidal creeks using a model simultaneously fitted to mark-resight and mark-recapture data. Rates of weekly loss (mortality plus emigration) were high (~10%). Sampling for tagged fish within- and outside of study creeks showed high site fidelity to each creek, suggesting that loss largely result from mortality rather than emigration. Estimated rates of apparent survival were lowest in the creek with the least instream- and watershed-level impacts relative to creeks with greater impacts; this was also the creek with direct (non-culvert) access downstream to a larger waterbody, suggesting that enhanced access by predators and/or greater rates of permanent emigration may have contributed to loss there. There was a positive relationship between minnow trap catch-per-unit-effort (CPUE) and density; CPUE was used to index density so that the relationship between it and habitat and urbanization effects could be examined in two additional (six total) study creeks. Highest CPUE estimates occurred early in each growing season and were associated with creeks possessing characteristics most representative of undisturbed salt marsh mosaics: high percentages of marsh coverage instream and downstream and greatest percentages of marsh edge. Given generally limited movement outside of creeks, differences in abundance among creeks likely result from different levels of recruitment that are related to salt marsh availability. Natural resource planners should prioritize preservation of salt marsh habitats to maintain abundance levels of this trophically important species.

North Carolina

Implanting 8-mm passive integrated transponder tags into small Brook Trout: Effects on growth and survival in the laboratory

Passive integrated transponder (PIT) tags are commonly used to investigate relationships between individual fish and their environment. The recent availability of smaller tags has provided the opportunity to tag smaller fish. In this study, we implanted 8-mm PIT tags into small Brook Trout Salvelinus fontinalis (35–50 mm FL; 0.35–1.266 g) and compared tag retention, growth rates, and survival of PIT-tagged fish with those of fish subjected to handling only or to handling plus fin clipping. We also examined how initial size at tagging affected absolute and specific growth rates of PIT-tagged individuals over time. We found that survival was 100%, tag retention was 96.7%, and fish size did not vary across treatments at 29 and 64 d posttagging. Additionally, there was no evidence that growth rate (FL or mass) was influenced by the initial size of the fish that were PIT tagged. Our results indicate that retention rates of 8-mm PIT tags surgically implanted into small Brook Trout are high and that there is no discernible effect on growth or survival in the laboratory. The ability to implant smaller PIT tags into smaller fish earlier in the season would allow researchers conducting PIT tag studies to expand demographic models to estimate survival of age-0 fish through the summer of their first year.

North American Journal of Fisheries Management

Estimating movement and survival rates of a small saltwater fish using autonomous antenna receiver arrays and passive integrated transponder tags

We evaluated the performance of small (12.5 mm long) passive integrated transponder (PIT) tags and custom detection antennas for obtaining fine-scale movement and demographic data of mummichog Fundulus heteroclitus in a salt marsh creek. Apparent survival and detection probability were estimated using a Cormack Jolly Seber (CJS) model fitted to detection data collected by an array of 3 vertical antennas from November 2010 to March 2011 and by a single horizontal antenna from April to August 2011. Movement of mummichogs was monitored during the period when the array of vertical antennas was used. Antenna performance was examined in situ using tags placed in wooden dowels (drones) and in live mummichogs. Of the 44 tagged fish, 42 were resighted over the 9 mo monitoring period. The in situ detection probabilities of the drone and live mummichogs were high (~80-100%) when the ambient water depth was less than ~0.8 m. Upstream and downstream movement of mummichogs was related to hourly water depth and direction of tidal current in a way that maximized time periods over which mummichogs utilized the intertidal vegetated marsh. Apparent survival was lower during periods of colder water temperatures in December 2010 and early January 2011 (median estimate of daily apparent survival = 0.979) than during other periods of the study (median estimate of daily apparent survival = 0.992). During late fall and winter, temperature had a positive effect on the CJS detection probability of a tagged mummichog, likely due to greater fish activity over warmer periods. During the spring and summer, this pattern reversed possibly due to mummichogs having reduced activity during the hottest periods. This study demonstrates the utility of PIT tags and continuously operating autonomous detection systems for tracking fish at fine temporal scales, and improving estimates of demographic parameters in salt marsh creeks that are difficult or impractical to sample with active fishing gear.

Marine Ecology Progress Series

Use of portable antennas to estimate abundance of PIT-tagged fish in small streams: Factors affecting detection probability

Portable passive integrated transponder (PIT) tag antenna systems can be valuable in providing reliable estimates of the abundance of tagged Atlantic salmon Salmo salar in small streams under a wide range of conditions. We developed and employed PIT tag antenna wand techniques in two controlled experiments and an additional case study to examine the factors that influenced our ability to estimate population size. We used Pollock's robust‐design capture–mark–recapture model to obtain estimates of the probability of first detection ( p ), the probability of redetection ( c ), and abundance ( N ) in the two controlled experiments. First, we conducted an experiment in which tags were hidden in fixed locations. Although p and c varied among the three observers and among the three passes that each observer conducted, the estimates of N were identical to the true values and did not vary among observers. In the second experiment using free‐swimming tagged fish, p and c varied among passes and time of day. Additionally, estimates of N varied between day and night and among age‐classes but were within 10% of the true population size. In the case study, we used the Cormack–Jolly–Seber model to examine the variation in p , and we compared counts of tagged fish found with the antenna wand with counts collected via electrofishing. In that study, we found that although p varied for age‐classes, sample dates, and time of day, antenna and electrofishing estimates of N were similar, indicating that population size can be reliably estimated via PIT tag antenna wands. However, factors such as the observer, time of day, age of fish, and stream discharge can influence the initial and subsequent detection probabilities.

North American Journal of Fisheries Management