Juvenile Common Snook Centropomus Undecimalis Research Articles

Nonnative Pike Killifish Do Not Exert Predatory Pressure on Juvenile Common Snook

AbstractThe Pike Killifish Belonesox belizanus is an established nonnative fish species that was first documented in south Florida, USA, in 1957 and secondarily in Tampa Bay tidal tributaries in 1994. Decreased abundance and altered size structure in small‐bodied fish populations have been linked to Pike Killifish introductions in both of these regions. Increases in the range and abundance of Pike Killifish in Tampa Bay waters and overlap in habitat usage with juvenile Common Snook Centropomus undecimalis have led to concerns about potential predation on early juvenile (≤125 mm TL) Common Snook. We investigated predation of Pike Killifish on early juvenile Common Snook through experimental predation trials and stomach content analysis of Pike Killifish from field sampling. During predation trials, fasted, large adult (≥104 mm TL) Pike Killifish were presented with one of three prey taxa: Common Snook (N = 139), Pike Killifish conspecifics (N = 68), and Eastern Mosquitofish Gambusia holbrooki (N = 68); the fate of the prey was recorded after 48 h. Common Snook with both intact (N = 70) and clipped (N = 69) anal spines were used as prey to investigate whether this structure deterred predation by Pike Killifish. Predation trials indicated that Pike Killifish were capable of consuming early juvenile Common Snook up to 60 mm TL and that the anal spine did not deter predation by Pike Killifish. Stomach content analysis was performed on 422 wild‐caught Pike Killifish from Tampa Bay tidal tributaries where early juvenile Common Snook co‐occurred, but no Common Snook remains were found in their diets. Combined, these studies indicate that despite being able to consume relatively large early juvenile Common Snook, Pike Killifish do not exert predatory pressure on early juvenile Common Snook in the wild and therefore do not appear to be a factor contributing to population‐level effects or delayed recovery in Common Snook populations.

Investigation into the Occurrence of Juvenile Common Snook Centropomus undecimalis, a Subtropical Estuarine Sport Fish, in Saltmarshes Beyond Their Established Range

Given recent trends of warming water temperatures and shifting fish distributions, detecting range expansion is important for resource management and planning. The subtropical common snook Centropomus undecimalis (hereafter referred to as snook) is an estuarine species that historically extended from the tropics to southern portions of Florida and Texas, but this range has been expanding for the past decade. We collected juvenile snook (n = 16; size range = 96–210-mm standard length [SL]) in saltmarshes of South Carolina, which is well outside their usual range but not unprecedented. Growth rates of juvenile snook in South Carolina (0.72-mm SL d−1) were similar to those reported for Florida during a cold period, but faster than rates reported for Florida during a recent period of mild winters (0.49-mm SL d−1). Based on collection and estimated hatch dates, and supported by winter water temperature records, juvenile snook overwintered for at least 1 year allowing them to grow to sizes that are typical for emigration from nursery habitats to open estuarine shorelines. Continued work is needed to determine whether there is potential for ongoing range expansion of snook to the region, and a strategy is proposed to focus on future research.

Coastal wetland restoration improves habitat for juvenile sportfish in Tampa Bay, Florida, U.S.A.

Increasing human populations and urban development have led to losses of estuarine habitats for fish and wildlife. Where resource managers are restoring coastal wetlands, in addition to meeting goals related to hydrologic connectivity, biodiversity, and recreational opportunities, efforts are being made to provide habitat that is suitable for juvenile sportfish. An 18-month study was conducted to compare juvenile sportfish use of natural, restored, and impacted sites along Tampa Bay, Florida, shorelines. Juvenile sportfish densities at restored sites were broadly comparable to natural sites and greater than at impacted sites. However, site-specific differences in sportfish use did occur within site types. For example, one restored site had significantly higher densities of red drum Sciaenops ocellatus than any other site, while black drum Pogonias cromis were found exclusively at another restored site. To evaluate whether the restored sites are providing suitable habitat for juvenile fish, we assessed growth (estimated from counts of daily rings on otoliths) and condition (determined by lipid analyses) of juvenile common snook Centropomus undecimalis, an archetypal coastal wetland-dependent species. Growth (0.43–0.56 mm SL/day) and condition (4.6–6.1% lipid of dry weight) exhibited only site-specific differences and did not vary among natural, restored, and impacted site types. Although mortality rates of juvenile sportfish were not determined, use of a 40-m seine found that densities of potential piscine predators in these coastal wetlands were relatively low compared to published studies of open estuarine shorelines. The restoration and creation of coastal wetlands in Tampa Bay provides improved habitat for juvenile sportfish.

Emigration-corrected seasonal survival of a size‑structured fish population in a nursery habitat

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 514:191-205 (2014) - DOI: https://doi.org/10.3354/meps10982 Emigration-corrected seasonal survival of a size‑structured fish population in a nursery habitat Andrew B. Barbour1,*, Aaron J. Adams2, Kai Lorenzen1 1School of Forest Resources and Conservation, Program of Fisheries and Aquatic Sciences, 7922 NW 71st Street, University of Florida, Gainesville, Florida 32653, USA 2Florida Institute of Technology, Biological Sciences, Vero Beach Marine Laboratory, 150 W University Boulevard, Melbourne, Florida 32901, USA *Corresponding author: ufsnook@gmail.com ABSTRACT: We studied how emigration and seasonal dynamics affect apparent survival estimates in a nursery habitat, thereby altering habitat valuation. During a 3 yr study, we marked 1917 juvenile common snook Centropomus undecimalis and resighted 85.7% with a telemetry array in 4 mangrove creeks. We grouped individuals by size class, marking year, and creek, and estimated survival (φ) using the Barker joint-data model. Using telemetry data, we estimated seasonal emigration probabilities and simulated the effect of emigration on φ estimates. We found a minimal effect of emigration on φ estimates, the magnitude of which may be explained by emigration underestimates due to telemetry coverage or high resighting rates reducing bias. We found seasonal and size-based variation in φ estimates. Our approach allowed survival estimation during a severe thermal-disturbance event that reduced survival in 2 creeks and may have had its impact mitigated in a third creek by an anthropogenic habitat alteration serving as a thermal refuge. Significant fine-scale spatial segregation of size classes likely acted to reduce intercohort cannibalism, thereby maintaining the high survival rates. We recommend caution when estimating apparent survival, since the lack of estimated survival bias was likely due to our extensive telemetry data, which buffered against the effects of emigration. We conclude that temporal variability in juvenile habitat use and survival requires seasonal classification of nursery habitat value, the consideration of multi-habitat nursery mosaics, and an exploration of the role of predation on habitat use. KEY WORDS: Mark-resighting · PIT tags · PIT tag antenna · Charlotte Harbor Full text in pdf format PreviousNextCite this article as: Barbour AB, Adams AJ, Lorenzen K (2014) Emigration-corrected seasonal survival of a size‑structured fish population in a nursery habitat. Mar Ecol Prog Ser 514:191-205. https://doi.org/10.3354/meps10982 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 514. Online publication date: November 06, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Effects of salinity on physiological conditions in juvenile common snook Centropomus undecimalis

This study describes the effects of different salinities on oxygen consumption, ammonia excretion, osmotic pressure, apparent heat increment, postprandial nitrogen excretion, and oxygen:nitrogen ratio in juvenile common snook Centropomus undecimalis. Oxygen consumption of fish fasting and fish feeding was statistically different in relation with salinity. Fish maintained at 0, 25, and 35 ppt invested more energy processing feed than fish maintained at 12 ppt. Fasting fish had lower ammonia excretion than feeding fish and excretion was reduced at high salinities. Snook can change the energetic substrate in function with salinity, from a mixture of protein and lipids and carbohydrates at 35 ppt to a more acute preference for proteins at lower salinities. This species changes osmotic plasma concentrations at extreme experimental salinities. The different salinities were the snook inhabits (0-36 ppt), have a direct effect on the physiology, inducing changes on the oxygen consumption, nitrogen excretion, changes on the energetic substrate and plasma osmotic pressure.

Community ecology of metazoan parasites of the later juvenile common snook Centropomus undecimalis (Osteichthyes: Centropomidae) from the coastal zone of the state of Rio de Janeiro, Brazil

Between April and December 2000, seventy-nine specimens of Centropomus undecimalis from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 01'S, 44 degrees 19'W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Nine species of metazoan parasites were collected: 1 digenean, 1 monogenean, 1 acantocephalan, 1 nematode, 4 copepods, and 1 isopod, and 96.2% of the fishes were parasitized by one or more metazoan, with mean of 85.3 +/- 122.9 parasite/fish. The digenean Acanthocollaritrema umbilicatum Travassos, Freitas & Bührnheim represented the majority of the parasites specimens collected, totaling, 94.7%. This species was the most abundant, prevalent, and dominant, showing positive correlation with the host's total body length and parasite abundance. The copepod species Acantholochus unisagittatus Tavares & Luque presented differences in abundance in relation to sex of host. The mean diversity in the infracommunities of C. undecimalis was H = 0.095 +/- 0.116, with no correlation with the host's total body length but correlated with the host's sex. No pair of parasite species showed positive or negative association or covariation. The dominance of digenean A. umbilicatum in the later juvenile common snook parasite community could be related with the predatory food habits of common snook and an apparent feeding transition period which might occasion great exposure to infective forms.