Schaffler J.J.,Old Dominion University |
Schaffler J.J.,Virginia Marine Resources Commission |
Young S.P.,Shawn Paul Young Environmental Consulting LLC |
Herrington S.,The Nature Conservancy |
And 2 more authors.
Transactions of the American Fisheries Society | Year: 2015
Abstract: Recent fish passage work in the Apalachicola–Chattahoochee–Flint (ACF) river system has coincided with an increase in the abundance and population estimates of adult Alabama Shad Alosa alabamae. Juvenile Alabama Shad are now common in the Flint River and Lake Seminole above Jim Woodruff Lock and Dam where they have historically been absent. Fish passage work has successfully restored spawning adults to these habitats; however, whether these juveniles are contributing to the observed population increases is unknown. Our objective was to determine the natal origins of adult Alabama Shad returning to spawn in the ACF river system, specifically whether fish passage efforts at the dam were contributing recruits to the adult population. Juvenile otolith chemistry profiles were significantly different between nursery locations above and below the dam but were complicated by temporal variation. However, including short term temporal variation in a discriminant function analysis (DFA) resulted in 88% correct classification, indicating that for the ACF river basin, short-term temporal variability in otolith chemistry does not pose a significant problem for predicting natal origins from cohorts that were not sampled. This finding relied most heavily on strontium, which did not exhibit temporal variation. Our data show that juvenile Alabama Shad produced upstream and downstream of the dam in the ACF can be reliably discriminated with an otolith chemistry approach. This discriminant function was applied to 140 adult Alabama Shad collected during 2010 and 2011 from below the dam and indicated that 86% of adults returning to spawn in the ACF system recruited from the Flint River above the dam. Neither collection year, sex, nor age affected the shad origins. These data indicate that juvenile Alabama Shad are able to emigrate successfully downstream through at least one lock and dam and contribute to the adult stock. © 2015, © American Fisheries Society 2015.
McBride R.S.,National Oceanic and Atmospheric Administration |
Snodgrass D.J.G.,National Oceanic and Atmospheric Administration |
Adams D.H.,Florida Fish And Wildlife Conservation Commission |
Rider S.J.,Fisheries Section |
Bulletin of Marine Science | Year: 2012
Dolphinfish, Coryphaena hippurus Linnaeus, 1758, reproductive biology is well known, but this study, which examined gonad histology, substantially increases estimates of dolphinfish spawning fraction and annual egg production. Ovaries were collected from 621 females in three Florida regions: the Keys, Cape Canaveral, and the panhandle. maturation and spawning were evident in all three regions. median size at maturity, 419 mm fork length (FL; 16.5 in, ∼3 mo), was not regionally specific around Florida. Recruitment of primary oocytes to vitellogenesis occurred asynchronously throughout the spawning season, and mature oocytes developed group-synchronously as batches. Thus, an indeterminate method was required to estimate egg production. Once mature, females spawned 70-180 d yr-1. Some females spawned in all months of the year, but spawning fraction was highest in winter and spring. Batch fecundity (BF) ranged from 20,000 to 620,000 eggs and was significantly related to FL: BF = 0.000005 × FL3.62. An egg production model estimated a range from 15 to 174 million eggs yr-1, two orders of magnitude higher than the previous estimate (0.24-3.0 million eggs yr-1) in the Florida Straits. This new, higher estimate arises because our large sample size of gonad histology permitted estimation of spawning fraction throughout the year. Spawning early and often should make C. hippurus resilient to overfishing, but other data gaps-particularly regarding bycatch mortality-confound our ability to evaluate the effectiveness of size regulations in the fishery. © 2012 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.
Rider S.J.,Fisheries Section |
Schell W.,PO Box 1133
Southeastern Naturalist | Year: 2012
We report on the first records of Acantharchus pomotis (Mud Sunfish) from Alabama. Three specimens were collected over a ten-year period from Beaver Dam Creek of the Tombigbee River drainage in Washington County, near Chatom, AL. These records represent the most western distribution and the only known population from the Mobile Basin for the Mud Sunfish.